C65-5o^-/>^9 ,^*'" *'^^o. ^ATES O^ NOAA Program Development Plan for SEASAT-A Research and Applications Washington, D.C. March 1977 •' / ■^■/^ iX-- U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Environmental Satellite Service Digitized by the Internet Archive in 2012 with funding from LYRASIS IVIembers and Sloan Foundation http://archive.org/details/noaaprogramdevelOOunit '^""fiSToTco** C6-^-So^::2>f<:; ^S^, NOAA Program Development Plan for SEASAT-A Research and Applications Washington, DC. March 1977 a o :u 2. I U.S. DEPARTMENT OF COMMERCE to Juanita M. Kreps, Secretary '^ National Oceanic and Atmospheric Administration B Robert M. White, Administrator National Environmental Satellite Service David S. Johnson, Director Mention of a commercial company or product does not constitute an endorsement by the NOAA National Environmental Satellite Service. Use for publicity or advertising purposes of information from this publication concerning proprietary products or the tests of such products is not authorized. FOREWORD In the 1770s, Captain James Cook first discovered the vastness of the Southern Hemisphere water mass and took the first major step in mapping the coast- lines of its continents. The 1870s saw the develop- ment and sailing of the first oceanic research ship fully dedicated to ocean science; thus, the early cruises of the H.M.S. Challengev resulted in 50 vol- umes of scientific papers, some still the leading publications for many geographical areas. Only time will put the 1970s into perspective for activities most responsible for ocean development. The deep-sea drilling project of the Glomar Chal- lenger, the Law-of-the-Sea Conferences, and the evolution of satellite applications are certain to be significant in the annals of ocean history. This program development plan considers the mar- ine applications of NASA's SEASAT-A spacecraft, designed for launch in 1978. SEASAT-A is the first space research platform dedicated to ocean science and application. The plan proposed by NOAA using analyses of data from the five sensors on SEASAT-A contains two key elements, both focused on the national mission of NOAA. A research ele- ment, to extend our understanding of the dynamics of the world's oceans, will form a 1970s parallel to the H.M.S. Challengev. A demonstration element, to address NOAA's operational mission, will be counterpart to the early mapping endeavors of Captain Cook. Ill CONTENTS Foreword iii Executive summary ES-1 Section 1. NASA SEASAT-A Program 1-1 1.1. User requirements 1-1 1.2. Instrument description and capabilities 1-1 1.2.1. Radar altimeter 1-2 1.2.2. Scatterometer 1-2 1.2.3. Synthetic aperture radar 1-3 1.2.4. Microwave radiometer 1-3 1.2.5. Visible and infrared radiometer 1-3 1.2.6. Instrument summary 1-3 1.3. Orbit, data, and mission characteristics 1-3 1.4. SEASAT-A experiment teams 1-5 1.5 SEASAT follow-on systems 1-5 Section 2. Scope and goals 2-1 Section 3. Benefits 3-1 3.1. Summary of NASA benefits studies 3-1 3.2. Improvements in existing servides 3-3 Section 4. Technical plan 4-1 4.1. Overview of planned activity 4-1 4.1.1. Summary of research 4-1 4.1.2. Summary of operational demonstrations .... 4-3 4.1.3. Milestones 4-3 4.2. Activity plan 4-3 4.2.1. Research 4-3 4.2.1.1. Studies of the coastal zone and lakes . 4-6 4.2.1.2. Studies of the open ocean 4-7 4.2.1.3. Geodesy 4-8 4.2.1.4. Polar studies 4-8 4.2.1.5. Hydrology 4-9 4.2.2. Demonstration 4-9 4.2.2.1. Meteorology 4-i; 4.2.2.2. Oceanography 4-1] 4.2.2.3. Living marine resources 4-1] 4.2.2.4. Geoid comparisons 4-1] 4.2.2.5. Operational satellite system 4-i: 4.2.3. Data handling 4-12 4.3. Interface with other major programs 4-15 4.4. Relationship to other satellites 4-16 4.4.1. TIROS-N 4-16 4.4.2. GOES 4-16 4.4.3. LANDSAT 4-16 4.4.4. GEOS-3 4-18 4.4.5. NIMBUS-G 4-18 4.4.6. DMSP 4-18 IV Section 5. Management plan 5-1 5.1. Program organization 5-1 5.2. Program responsibilities 5-1 5.2.1. Program management team 5-1 5.2.2. SEASAT Project . 5-1 5.2.3. Research and demonstration team 5-1 5.3. Implementation 5-2 5.4. Oceanic community involvement 5-2 5.5. Management and reporting procedures 5-2 5.5.1. PDP updates 5-2 5.5.2. Project coordination meetings 5-2 5.5.3. NOAA progress and issues review 5-2 5.5.4. Budget reports and reviews 5-2 5.5.5. Experiment design reviews 5-2 5.5.6. Contractor reviews . 5-2 5.5.7. Project documentation 5-3 5.5.8. Technical reports . 5-3 5.5.9. Scientific and technical papers 5-3 5.6. Coordination with other agencies 5-3 Appendix I. SEASAT-A capabilities I-l Appendix II. Glossary of terms II-l Appendix III. Resource impacts III-l Appendix IV. Technical plan IV- 1 FIGURES Frontispiece. --SEASAT-A flight configuration viii ES-1.--N0AA SEASAT-A Program and interface activities ES-3 ES-2. --Basic Research Activity in support of NOAA goals and mission ES-6 ES-3. --Basic Demonstration Activity in support of NOAA goals and mission ES-7 1-1 . --Geophysical oceanographic measurement needs 1-2 1-2. --Geophysical oceanographic measurement capabilities for SEASAT-A 1-4 1-3. - -SEASAT-A sensor characteristics 1-4 2-1. --NOAA mission relationships to SEASAT-A data and information 2-2 4-1 . --Relationship between the NOAA program and budget structure and the SEASAT-A experimental activity 4-2 4-2. --Research-to-research relationships in the planned NOAA . ,. SEASAT-A experimental activity 4-3. --Altimeter geometry for geoid determination 4-8 4-4. --Research-demonstration relationships 4-10 4-5. --Performance and benefits study for a mid-80s operational environmental system 4-13 4-6. --Systems analysis methodology and decision-making 4-14 4-7. --NOAA SEASAT-A activities relevant to major oceanographic and atmospheric programs 4-17 I-1.--Skin depth vs. frequency characteristics in the microwave region I-l 1-2. --Skin depth vs. salinity at 1.35 GHz and 20°C 1-2 1-3. --Specular emissivity of model seawater vs frequency for 3°C 1-2 1-4. --Attenuation of electromagnetic energy by atmospheric gases 1-3 1-5. --Radar attenuation-brightness temperature relationships 1-3 1-6. --Geophysical oceanographic measurement capabilities for SEASAT-A 1-4 1-7. --SEASAT-A sensor characteristics 1-4 I -8. --SEASAT-A sensor swaths 1-5 1-9. --SEASAT-A spatial grids and swathing 1-6 I-IO. --Average radar cross section as a function of time 1-7 I-ll. --Comparison of the altimetry geoid profiles over the Puerto Rico Trench and land mass 1-8 1-12. --The S193 scatterometer response compared to in-situ measurements of wind at sea, 30 days into the first Skylab mission 1-9 1-13. --Radar backscatter as a function of azimuth angle for a 12.86 m s"^ windspeed 1-9 I-14.--SMMR nominal parameters I-IO 1-15. --Brightness temperature as a function of incident angle with wind-roughened ocean surface as a parameter I-ll 1-16. --JPL imaging radar, ocean swells, digital two dimensional intensity spectra and enhancement 1-12 1-17. --Principles of a Synthetic Aperture Radar system 1-13 1-18. --SEASAT-A trajectory and ground station coverage 1-14 1-19. --SEASAT-A global coverage • 1-15 vi 1-20. --SEASAT-A ground trace pattern (definition phase orbit) 1-16 1-21. --Elements of the SEASAT-A end-to-end data system 1-17 I-22.--SEASAT-A instrument data flow 1-18 1-23. --Near-real-time sea surface temperature analysis 1-19 1-24. --Experiment team interface data flow 1-20 lV-1 . --Relationship between wind and circulation-related experiments IV-2.--Life cycle of the menhaden IV-15 TABLES 1-1. --Basic orbital characteristics 1-3 3-1 . --Summary of most likely range of benefits exclusive to SEASAT 3-2 4-1. --Major SEASAT-A PDP milestones 4-4 I- 1. --Skin depth at SEASAT-A frequencies 1-2 1-2. --Basic orbital characteristics 1-14 1-3. --Data flow element responsibilities 1-17 111-1. --Activity cost for research elements ($K) 1II-2 111-2. --Activity cost for demonstration elements ($1^) 111-3 1 11- 3. --Block-funded asset requirements for aircraft ($K) 1 1 1-4 111-4. --Block-funded assets for computer requirements ($K) III-5 111-5. --Fiscal year summary of program development plan projected cost ($K) 1II-5 IV- 1.- -SEASAT-A support relationship to international experiments lV-17 IV-2. --SEASAT-A support relationships to National programs IV-18 IV- 3. --SEASAT-A support relationships to NOAA programs IV- 19 vii TRANET BEACON ANTENhM MULTI-CHANNa MICROWAVE RADIOMETER lASER RETROREFlfCTOR V/IR RADIOMETER SAR DATA LINK ANTENNA SEASAT-A flight configuration Vlll EXECUTIVE SUMMARY The application of satellite technology to marine problems and research will be focused sharply during 1978. two research satellites, seasat-a and nimbus-g, and one operational satellite, tiros-n, will be launched during THIS PERIOD. GOES OPERATIONAL SUPPORT WILL CONTINUE. ThE SEASAT-A SYSTEM IS UNIQUE BECAUSE ITS INSTRUMENT COMPLEMENT IS FULLY DEDICATED TO OCEANIC REQUIREMENTS, WHEREAS THE REMAINING SATELLITES HAVE SPECIFIC INSTRUMENTS THAT ADDRESS OCEANIC NEEDS. ADDITIONALLY, THE SENSORS ON SEASAT-A WILL PRO- VIDE NEAR ALL-WEATHER MONITORING OF THE OCEAN SURFACE BY UTILIZING THE MICROWAVE REGION; AND, WITHIN THE SUITE OF MICROWAVE INSTRUMENTS, EACH BASIC TYPE OF MICROWAVE SENSOR IS REPRESENTED. Because SEASAT-A offers an excellent opportunity to determine those BENEFITS THAT ACCRUE TO THE NATIONAL OcEANIC AND ATMOSPHERIC ADMINISTRATION (NOAA), A SPECIAL Program Development Plan (PDP) is offered to delineate a measurements and evaluation program that contributes to the mission of noaa: • Explore, map, and chart the global ocean and its living resources. • Manage, use, and conserve those resources. • Describe, monitor, and predict conditions in the atmosphere, ocean. Sun, and space environment. • Issue warnings against impending destructive natural events. • Develop beneficial methods of environmental modification. • Assess the consequences of inadvertent environmental modification over a period of time. ".•;■ The PDP focuses on two primary aspects, one dealing with research and THE OTHER DEALING WITH OPERATIONAL DEMONSTRATION. ThE RESEARCH ELEMENT IS NECESSARY FOR BASIC UNDERSTANDING OF SATELLITE-ACQUIRED MARINE DATAj THE DEMONSTRATION ELEMENT WILL ASSESS THE BENEFITS POSSIBLE WITH OPERATIONAL SEASAT-TYPE INSTRUMENTS. ES-1 The potential benefits to the marine community have been studied in de- tail BY the National Aeronautics and Space Administration (NASA) with bene- fits RANGING FROM $900 TO $2700 MILLION (1975 DOLLARS) FOR 1985-2000 (10% discount rate). Excluding costs of unique ground-data handling equipment needed to process^ disseminate^ or utilize the information produced from seasat-type data, the cost of an operational seasat system during this per- iod is around $600 million. although some benefits or costs are not direct- ly assignable to noaa, the major benefits are keyed to improvements in noaa's weather forecast program. similarly, cost assessment of a ground system to support an operational system can be accurately determined only by studying AND EXECUTING SEASAT-A DATA. HeNCE, A STRONG NEED EXISTS FOR ACTIVE RE- SEARCH AND OPERATIONAL PARTICIPATION BY NOAA IN THE SEASAT-A EFFORT. The ULTIMATE OBJECTIVES OF THE NOAA SEASAT-A Program are to: • Establish those environmental measurements and acquisition techniques that can be made from an operational system with efficiency and economy. • Determine the geoid to the accuracy needed to serve as a reference sur- face FOR SEA-SURFACE TOPOGRAPHY. • Continue to improve the understanding of the complex dynamic behavior of THE ocean and THE SEA-AIR INTERFACE. • Contribute to major ongoing international, national, and NOAA programs WITH synoptic environmental data. Each objective is necessary for fulfillment of the NOAA mission. Most im- portantly, THE coupling BETWEEN SEASAT-A AND THE OCEAN SURFACE PROGRAM IS MULTIFACETED. FiGURE ES-1 ILLUSTRATES THIS COUPLING. ThE ROWS IN THE UPPER ECHELON ARE THE MORE CONVENTIONAL DATA SOURCES AND ARE VALUABLE IN THEM- SELVES. Boxes B, E, F, and I represent the ongoing NOAA data collection, ANALYSIS, AND INFORMATION SYSTEMS LEADING TO NOAA PRODUCTS AND BECOME THE VEHICLE FOR SEASAT-A PERFORMANCE EVALUATION. BoXES B, C, F, AND G REPRESENT GROUND-BASED ACTIVITIES THAT COLLECT THE "SURFACE TRUTH" DATA FOR THE SEASAT-A PROGRAM. NASA and NOAA will be highly dependent on each other for ES-2 NOAA E NATIONAL. INTI RNATIONAL □ NOAA ACTIVITIES REQUIRED FOR SEASAT EVALUATION I I JOINT OR OTHER RELATED ACTIVITIES <- -1 NASA - LED SEASAT ACTIVITY ( I ^ NASA SEASAT-. PROJECT ^ -^ SEASAT DATA COLLECTION & REDUCTION r Figure ES-1.--N0AA SEASAT-A Program and interface activities THIS ELEMENT OF ACTIVITY. EXPERIMENTS CONDUCTED IN BOX B ARE SCHEDULED IN BOX A (the PDP) and WILL ALSO PROVIDE TAILORED SURFACE TRUTH SUPPORT^ AND DATA FROM AIRCRAFT AND OTHER SATELLITES. ThE NASA SEASAT-A PROJECT (bOX D) WILL PROVIDE GEOPHYSICAL DATA TO A WIDE VARIETY OF USERS FOR ANALYSES (BOX H) AND ULTIMATELY FOR SPECIFIC APPLICATIONS (BOX K) . ThE PDP OUTLINES THE NOAA ACTIVITIES IN BOXES H AND K AS INTEGRATED WITH THE ONGOING IN'SITU SYSTEMS. Performance Evaluation (box J) will be conducted by the appro- priate NOAA Major Line Components (PlLCs) and used as the basis for Cost- Benefit Studies (box L) to determine the best or optimum-mix system to sat- isfy THE four major OBJECTIVES OF THE NOAA SEASAT-A Program, SEASAT-A. WHICH WILL OPERATE IN AN ORBIT OF 800-KM ALTITUDE AND 108O IN" CLINATIONv WILL CARRY SENSORS TO PROVIDE THE DATA IN BOX D. ThE GENERAL sensor applications are summarized as: • The altimeter: This nadir-looking instrument provides a very short PULSE signal that MEASURES THE DISPLACEMENT BETWEEN THE SATELLITE AND ES-3 THE OCEAN SURFACE TO A PROCESSED ACCURACY OF 10 CM EVERY 18 KM AND THE RMS ROUGHNESS OF THAT SURFACE TO ABOUT 1 M. • The RADAR: A 100-km swath-width image of the ocean surface will be GENERATED WITH A SPATIAL RESOLUTION OF 25 M. On THE AVERAGE^ AN OCEAN AREA (within RANGE OF A READOUT STATION) WILL BE IMAGED EVERY 18 DAYS. • The scatterometer: Low to intermediate surface wind velocity will be determined over a swath width of about 1200 km^ providing global cover- AGE (175° latitude) EVERY 36 HOURS ON A 100 KM GRID BASIS. • The MICROWAVE radiometer: Atmospheric water vapor and liquid^ ice BOUNDARIES AND LEADS^ SEA-SURFACE TEMPERATURE^ AND INTERMEDIATE TO HIGH WIND SPEEDS ARE PROVIDED OVER A SWATH WIDTH OF ABOUT 1000 KM EVERY 36 HOURS. The spatial resolution ranges from 25 km for ice features to 125 KM FOR SEA-SURFACE TEMPERATURE. • The VISIBLE and IR (Infrared) Radiometer: the prime purpose of this INSTRUMENT IS TO PROVIDE 7-KM SPATIAL RESOLUTION IMAGERY FOR FEATURE identification of the MICROWAVE DATA. Figure ES-1 also represents the chronological sequence by which the NOAA EFFORT WILL BE ACCOMPLISHED. ThE ACTIVITIES IN THE COLUMN OF BoXES B^C^ AND D ARE CONDUCTED PRIMARILY DURING THE EARLY PERIOD OF THE PLANNED ONE-YEAR- LIFE OF SEASAT-A with EMPHASIS ON RESEARCH, GIVING WAY TO A MIXED RESEARCH AND DEMONSTRATION EFFORT (BOXES F^G, AND H) . ALTHOUGH THE ACTUAL CAPABIL- ITIES AND LIMITATIONS OF THE SEASAT-A SYSTEM ARE TO BE ESTABLISHED BY THE RESEARCH EXPERIMENTS, THE NOAA PROGRAM WILL EMPHASIZE OPERATIONAL DEMONSTRA- TION EXPERIMENTS DURING THE LATER PHASES OF THE SEASAT-A MISSION (BOXES LJ, AND K). The DEFINITION OF THE BEST POSSIBLE OPERATIONAL CONFIGURATION WILL be conducted last (boxes l and j). The PDP-allocated resources will principally support activities in those BOXES drawn with HEAVY LINES. ThE ANALYSES AND APPLICATIONS REQUIRED IN BOXES H AND K, AS RELATED TO NOAA ACTIVITIES, MUST ALSO BE SUPPORTED. NOAA SCIENTISTS ALREADY PARTICIPATE IN THE ACTIVITIES OF BOXES C,D, AND G AND WILL CONTINUE TO DO SO AT NO COST TO THE NOAA SEASAT-A PROGRAM. ES-4 The NASA SEASAT-A Project will distribute data to three agencies: NASA FOR internal use INCLUDING THE EXPERIMENT TEAMS (BOXES C AND G), THE NaVY'S Fleet Numerical Weather Central (FNWC), and NOAA's Environmental Data Ser- vice (EDS). EDS WILL then duplicate all data for the NOAA SEASAT-A experi- menters INCLUDED IN THIS PDP FOR THE MARINE COMMUNITY AT LARGE . EDS WILL BE REIMBURSED FOR COSTS OF DATA PROVIDED TO NOAA AND THE MARINE COMMUNITY; BUT BLOCK FUNDS (aS SPECIFIED IN THE PDP) WILL BE PROVIDED FOR NOAA SEASAT PDP INVESTIGATORS WHILE OTHERS WILL PAY FOR DATA SETS. Special attention will be given to the NOAA use of near real-time data. Presently^ it is planned that the near real-time data will be converted to geophysical units by FNWC and transferred to the National Meteorological Center (NFIC) of the National Weather Service (NWS) for analysis and in- gestion into numerical models. An option is to bypass FNWC and receive data DIRECTLY FROM THE FAIRBANKS^ ALASKA^ RECEIVING STATION. ThIS WOULD REQUIRE A COMMERCIAL SATELLITE RECEIVING STATION IN THE VICINITY OF NFIC, AND NEITHER THIS INSTALLATION NOR ADDITIONAL PROCESSING COST ARE INCLUDED IN THE PDP. A SUMMARY OF THE BASIC RESEARCH ACTIVITY IS SHOWN IN FIGURE ES-2. ThE RESEARCH IS IN THREE PRIME DISCIPLINE AREAS: METEOROLOGY, OCEANOGRAPHY, AND GEODESY. Two SPECIAL SUPPORT FUNCTIONS FOR BASIC OBSERVATIONAL DATA COL- LECTION AND ARCHIVING OF ALL DATA ARE INCLUDED. ThE DATA COLLECTION IN- CLUDES SPECIAL INSTRUMENTS AND AIRCRAFT SUPPORT ACTIVITIES NEEDED FOR THE "sea truth" ACTIVITY IN BOXES B,C,D, AND F OF FIGURE ES-1 . SCALE SIZES have been noted to establish the areal extent of the planned activity. Thus, sea truth is conducted on a local scale (up to hundreds of kilometers), meteorology at all scales including regional (up to thousands of kilometers), oceanography at local and regional scales, and geodesy at all scales. ex- cept for the eds archiving and data dissemination activity, each prime dis- cipline is supported by two or more mlcs, with all mlcs involved to various degrees in the oceanographic activity. ES-5 Figure ES-2. --Basic Research Activity in support of NOAA goals and mission An active interface with other major NOAA, national, and international PROGRAMS IS TO BE MAINTAINED ON A NONINTERFERENCE BASIS. MaJOR EXPERIMENTAL SCHEDULES WILL BE USED TO INFLUENCE THE SEASAT-A DATA COLLECTION PRIORITIES AS CONDUCTED BY NASA, ThE MOST SIGNIFICANT INTERFACE IS PLANNED FOR THE First GARP Global Experiment (FGGE) wherein it is anticipated that SEASAT-A WILL provide a large PORTION OF THE EQUATORIAL AND SOUTHERN HEMISPHERE DATA TO FGGE WHILE THE NORTHERN HEMISPHERE WILL SERVE AS A QUALITY CONTROL REGION ON SEASAT-A PERFORMANCE. ThE PDP does not CONTAIN RESOURCES TO SUPPORT EX- PLICITLY THESE OTHER PROGRAMS; BUT JOINT EXPERIMENTS WILL BE CONDUCTED TO EXPAND MUTUALLY THE DATA BASE AND DATA WILL BE EXCHANGED BETWEEN SEASAT AND THESE PROGRAMS. The RESEARCH PORTION OF THE PDP IS ORGANIZED WITH REGARD TO COASTAL ZONE AND Lakes, Open Ocean, Geodesy, Polar, and Hydrology activities. More than 20 research experiments or analyses are to be accomplished within the PDP, and these are noted by title in figure ES-2. ES-6 Figure ES-3. --Basic Demonstration Activity in support of NOAA goals and mission Figure ES-3 is a summary of the planned Demonstration Activity to be con- ducted BY NOAA. Initial results from the Research Activity will be used to MAKE the details OF THE DEMONSTRATION ACTIVITY FINAL. BaSED ON CURRENT knowledge of data needs and SEASAT-A capabilities, DEMONSTRATION PROGRAMS WILL BE UNDERTAKEN IN FOUR AREAS: LIVING MARINE RESOURCES, METEOROLOGY, OCEANOGRAPHY, AND GEODESY. ThE CULMINATION OF THESE DEMONSTRATIONS WILL BE THE DEFINITION OF A MID-80'S OPERATIONAL SATELLITE SYSTEM BASED ON BENEFIT ANALYSIS AND SYSTEM COST, INCLUDING BOTH SPACE AND SURFACE HARDWARE, SOFTWARE AND data/ INFORMATION DISTRIBUTION. EaCH OPERATIONAL DEMONSTRATION IS UNIQUE. As AN EXAMPLE, THE RESULTS OBTAINED IN THE FISHERIES AREA POTENTIALLY RE- PRESENT A DIRECT BENEFIT TO NOAA, THE OTHER BENEFITS BEING "SAVINGS" IN THAT IMPROVEMENTS IN MARINE WEATHER FORECAST OR GEOID DEFINITION LEAD TO A RE- DUCTION IN DAMAGE TO LIFE AND PROPERTY RATHER THAN INCREASED REVENUES. ThE FISHERIES DEMONSTRATION IS PARTICULARLY IMPORTANT IN THE LIGHT OF EXTENDED JURISDICTION NEEDS AND I^ARINE RESOURCES MONITORING, ASSESSMENT, AND PRE- DICTION (FIARMAP) EFFORTS. Equally critical to the long-term evaluation of ES-7 SEASAT-TYPE OPERATIONAL SYSTEMS IS IMPROVEMENT IN MARINE WEATHER FORECASTS THAT INVOLVE BOTH THE PLANNED METEOROLOGY AND OCEANOGRAPHY DEMONSTRATION. Ice ANALYSIS AND FORECAST IMPROVEMENT IS INCLUDED AS A PART OF THE MARINE WEATHER DEMONSTRATION PROGRAM. As NOTED EARLIER, A LARGE SEGMENT OF THE POTENTIAL BENEFITS FROM AN OPERATIONAL SYSTEM HINGE ON IMPROVED WEATHER FORECASTS THAT ARE OF DIRECT CONCERN TO NOAA. ThIS PDP^ WHEN EXECUTED, WILL ESTABLISH THESE BENEFITS IN A QUANTITATIVE MANNER. The GEODESY DEMONSTRATION DIFFERS FROM THE OTHER DEMONSTRATION ACTIVITIES IN THAT IF IT IS SUCCESSFUL (SEASAT'A MEETS ITS FULL PERFORMANCE SPECIFI- CATION), NO FOLLOW-ON OPERATIONAL SYSTEM NEEDS TO BE FLOWN FOR GEODETIC PUR- POSES, AT LEAST NOT IN THE MID-1980S. OtHER AREAS (PARTICULARLY WAVES AND tides) WOULD BENEFIT FROM CONTINUED OPERATIONAL USE OF A SEASAT-TYPE ALTI- METER USED FOR GEODETIC DATA. In contrast to the research activity where several MLCs are usually IN- VOLVED IN EACH EXPERIMENTAL AREA, FIGURE ES-3 ILLUSTRATES THE CLOSE TIE BE- TWEEN SPECIFIC OPERATIONS AND ONLY ONE OR TWO MLCs. NESS IS IDENTIFIED WITH EACH MLC IN A SUPPORTING ROLE, BUT ONLY THE APPROPRIATE FILC LEADS EACH DE- MONSTRATION EFFORT. This PDP is organized with an introduction to the NASA SEASAT-A charac- teristics, A DISCUSSION OF MANNER IN WHICH THE SEASAT-A CAf^ABILITIES RELATE TO THE MISSION OF NOAA, AN OUTLINE OF POTENTIAL BENEFITS TO NOAA, A TECHNI- CAL PLAN OF ACTIVITY, AND A MANAGEMENT PLAN. DETAILS ON THE NEEDED, BUT UNAPPROVED, RESOURCES ARE SUMMARIZED IN APPENDIX III, SPECIFIC CONTRACTS WILL BE GIVEN ON A COMPETITIVE BASIS TO THE MARINE COMMUNITY OF INDUSTRIAL, ACADEMIC, AND OTHER GOVERNMENT RESEARCHERS TO IMPLEMENT THE NOAA EFFORT. AlL PLANNED ACTIVITY IS SUBJECT TO SEASAT-A RESOURCE LIMITATIONS. ES- SECTION 1. NASA SEASAT-A PROGRAM The National Aeronautics and Space Admin- istration (NASA) is responsible for space research and the development of applications in response to user needs. The Earth and Ocean Physics Applications Program (EOPAP) within the NASA Office of Applications plans to launch in May 1978 a satellite system, designated SEASAT-A, dedicated to near all- weather observations of the ocean surface. The platform is unique in several ways. First, the prime payload is composed solely of microwave instruments, the exception being a visible and infrared scanner used for feature identification. Second, the microwave instruments consist of three active sensors and one passive sensor with characteristics having been defined for marine applications. The result is a pay- load dedicated to marine observations. Third, the selection of the instruments and instrument characteristics has been accomp- lished jointly by NASA and user scientists. Under the auspices of NASA, the User Working Group (now the Oceanology Advisory Sub- committee) is chaired by Dr. John R. Apel of NOAA. This group continues to provide a unique forum for user needs and requirements to be addressed. A second research satellite system that enhances and extends the SEASAT-A capabili- ties is planned for launch in mid-1978. This is the Nimbus-G system that carries a complement of eight sensors, one of which is a microwave radiometer system identical to the radiometer on SEASAT-A and hence will increase ocean coverage both temporally and geographically. This radiometer on Nimbus-G is considered an integral part of the NOAA SEASAT-A Program. 1 . 1 User Requirements In June 1973, a report was prepared by NOAA scientists (Apel and Sherman 1973)* to *Apel, John R., and Sherman, John W.,III, "Monitoring the Seas From Space: NOAA's Requirements for Oceanographic Satellite Data" (A Report to the NOAA Satellite Plans and Requirements Steering Group) , Report AOML-LORS 6.73.1, National Oceanic and Atmospheric Administration, U.S. Department of Commerce, Miami, Fla., June 1973, 38 pp. (Apel is now with NOAA's Pacific Marine Environmental Laboratory, Seattle, V/ash.) focus the attention of not only NOAA invest- igators but also the marine community in general on the evolving potential applica- tions of satellite systems. This report « "Monitoring the Seas from Space: NOAA's Requirements for Oceanographic Satellite Data," became a cornerstone in the require- ments planning by the Oceanology Advisory Subcommittee. Figure 1-1 is the summary statement of requirements for SEASAT-A. It is based on the measurement and monitoring needs for wave heights, directional spectra, and images; near all-weather measurement of sur- face temperature and winds; sea and lake ice dynamics; and the marine geoid, tides, currents, and oceanic pressure gradient, setup, and storm surge. The relationship of the SEASAT-A instruments to these require- ments is complex. Many of the instrument signatures will be used for quantitative analyses. Unlike the early meteorological and land-oriented research satellites, the primary products of SEASAT-A will not be images but will be environmental data in geophysical units. An exception will be the synthetic aperture radar, which does not have the same space heritage as the remaining instruments. New imagery inter- pretation techniques will be an important part of the radar analysis. The requirements have typically been specified with regard to operational data needs. Often, it has been difficult to translate the known in situ requirements into remote-sensing requirements. The value of the satellite lies in the near real-time synoptic acquisition of data, not neces- sarily in great precision at a specific number of points. The SEASAT-A surface wind data will be the equivalent of approximately 20,000 ship reports each day. This may not seem impressive until one notes this is about an order of magnitude larger than that now provided by surface vessels. Indeed, equally impressive is the uniform spacing of the satellite data compared with the concen- tration of in situ data along major shipping routes. The specific justification of the environ- mental requirements for SEASAT-A is an implicit part of the research and demon- stration program as described in paragraph 4.2. The economic benefits that potentially accrue to NOAA and the Nation when these environmental requirements are addressed operationally are discussed in section 3. 1-1 MEASUREMENT RANGE PRECISION/ACCURACY RESOLUTION SPACIALGRID TEMPORAL GRID TOPOGRAPHY GEOID 5cm - 200m <±10cm <10km WEEKLY TO MONTHLY CURRENTS, SURGES, Etc. lOcm - 10m 5 - 500cm/s <±IOcm + 5cm/s 10 - 1000m 50m 25m 25m 25m 2 -4/d ICEBERGS >10m 1 -50m 1 -50m OCEAN FEATURES OPEN OCEAN 50 - 500m TWICE DAILY TO DAILY COASTAL 10 -100m SALINITY - 30ppt ±0.1 - Ippt 1 - 10km 100km WEEKLY SURFACE PRESSURE 930 - 1030mb ±2-4mb 1 - 10km 1 -10km HOURLY Figure 1-1 .--Geophysical oceanographic measurement needs 1.2. Instrument Description and Capabilities The SEASAT-A satellite will carry four microwave sensors consisting of an alti- meter, scatterometer, radar and radiometer, and a visible and infrared scanner designed primarily for feature identification. There is a strong space heritage for each of the instruments with the exception of the radar. As such, each instrument has a high proba- bility of meeting its mission objective. Direct comparisons will be made between each instrument over the same regions of the ocean. The data rates on four of the in- struments will be sufficiently low so that global data can be processed within hours (a maximum of six) after acquisition and can be used in a real-time mode in existing models used for world weather prediction. The characteristics of each sensor will be dis- cussed as they relate: to the environmental measurements required by NOAA, and a more comprehensive description of the NASA SEASAT-A Program and instruments is given in appendix A. The NASA SEASAT-A Project is under the direction of the Jet Propulsion Laboratory (JPL) of the California Institute of Techno- logy at Pasadena. The SEASAT-A satellite bus is the Agena space vehicle. 1.2.1, Radar Altimeter The radar altimeter will provide a very short pulse (3 ns) by which both the dis- tance from the spacecraft to the ocean sur- face will be measured (< -20 cm rms) and the wave height determined from 1 to about 25 m (11 or 10%, whichever is larger). The in- strument, operating at 13.9 GHz, will pro- vide geodetic, topographic, and sea-state measurements along a narrow footprint below the spacecraft (1.6-12 km). The SEASAT-A altimeter is an improved instrument from the sensors flown on SKYLAB and GEOS-3. 1.2.2. Scatterometer The SEASAT-A Scatterometer System (SASS) is an active sensor operating at 13.9 or 14.595 GHz and is designed primarily to serve as a low to intermediate wind velocity anemometer measuring roughness related to winds with an accuracy of ±2 m/s or 10% (whichever is larger) and 120° in angle. The swath coverage is about 1000 km, and the range of the wind-field measurement is from about 3 m/s to potentially 25 m/s. Global coverage (95%) is accomplished in 36 h. The SASS is an advanced version of the scatter- ometer sensor flown on SKYLAB. 1-2 1.2.3. Synthetic Aperture Radar The Synthetic Aperture Radar (SAR) is a new space instrument designed to provide 25-m spatial resolution images and wave directional spectra over a 100-km swath width. The SAR will operate at the rela- tively low frequency of 1.37 GHz and as a result will have excellent cloud and rain penetration capability. Two prime appli- cations are for coastal wave refraction analyses and sea and lake ice dynamics. The SAR and SEASAT-A orbit characteristics are such that the orbit repeats exactly every 152 d, but a given surface feature may be seen in the SAR image for several conse- cutive days every 70 d. 1.2.4. Microwave Radiometer The Scanning Multifrequency Microwave Radiometer (SMMR) will be flown on both SEASAT-A and Nimbus-G. Accordingly, the SEASAT-A SMMR will provide global coverage every 36 h from tll^ latitude, whereas the Nimbus-G SMMR will require 72 h for global coverage but will fully cover the polar re- gions. The five frequencies (6.6, 10.69, 18, 22.235, and 37 GHz) of SMMR will permit the instrument to serve as an intermediate to high wind field anenometer (no wind dir- ection) and to measure brightness temper- ature related to atmospheric corrections for liquid and vapor water, sea-surface temper- ature, and ice fields. The SMMR system has a heritage from instruments flown on SKYLAB and Nimbus -5 and Nimbus -6. of several observations per day are re- quired, based largely on the needs of the existing -in situ network, while SEASAT will typically require 36 h (0.67 observations per day) for the environmental data cycle. As previously noted, however, certain forms of environmental data sets will be an order of magnitude greater than now available through in situ techniques, and the SEASAT-A temporal coverage is ascertained to be more than adequate for research and demonstration purposes. 1.3. Orbit, Data and Mission Characteristics The general orbital characteristics of SEASAT-A are defined in table 1-1. These parameters are not likely to change, but within them there remains considerable flex- ibility that establishes the detail charac- teristics of the orbit. The orbit is 172° latitude, but with the swath widths of the SASS, SMMR, and VIR the coverage exceeds i75°. The altimeter covers l72°, but the SAR covers 75°N and 69°S because of its right-oriented position with respect to the trajectory. One must distinguish between data to be acquired in near-real-time and data to be used for non-real-time applications. Only the readout station (ULA) at Fairbanks, Alaska, will acquire data for real-time use (up to 6 h after initial acquisition by the sensor) . The data interfaces are discussed in detail in appendix A. The only data loss for real-time use is from the central part of Europe and a small segment of the Pacific Ocean off South America. 1.2.5. Visible and Infrared Radiometer Table 1-1. --Basic orbital characteristics The Visible and Infrared Radiometer (VIR) is a modified Scanning Radiometer (SR) flown on the NOAA series of operational satel- lites. The two channels provide day-and- night coverage of both cloud conditions and major ocean features. The prime modifica- tion of the SR is to correct for altitude differences between SEASAT (800 km) and NOAA (1300 km). 1.2.6. Instrument Summary A summary of the SEASAT-A instruments in the preceding sections and in appendix A is given in figures 1-2 and 1-3. The most meaningful comparison is between the user requirements as specified in figure 1-1 and the sensor payload capability as given in figure 1-2. Temporal coverage requirements Period 100.75 min Altitude 794-808 km, non-sun- synchronous Orbits/d 14.3 Orbit repeat (exact) 152 d Inclination 108° Global coverage « 36 h for 95%. Payload Microwave radiometer; V§IR (oceanic radiometer; radar sensors) MEASUREMENT RANGE PRECISION/ACCURACY RESOLUTION, km SPAOALGRID TEMPORAL GRID TOPOGRAPHY GEOID ALTIMETER 5cm - 200m <±20cm 1.6-12 -10 LESS THAN 6 MONTHS CURRENTS, SURGES, Etc. 1 0cm - 1 Om SURFACE WINDS AMPLITUDE MICROWAVE RADIOMETER 7 - 50m/s ±2m/sOR±10% 50 SO 36h TO 95% COVERAGE SCATTER- OMETER 3 - 25m/s ±2m/sOR 10% 50 100 36h TO 95% COVERAGE DIRECTION - 360° ±20° GRAVITY WAVES HEIGHT ALTIMETER 0.5 -25m ±0.5 TO 1.0m OR ±10% 1.6-12 NADIR ONLY l/14dNEAR CONTINENTAL U.S. LENGTH IMAGING RADAR 50 -1000m ±10% 50m DIRECTION - 360° ±15% SURFACE TEMPERATURE RELATIVE V&IR RADIOMETER - 2 - 35°C CLEAR WEATHER 1.5° ~5 ~5 36h ABSOLUTE 2° RELATIVE MICROWAVE RADIOMETER - 2 - 35°C ALL WEATHER 1° 100 100 36h ABSOLUTE 1.5° SEA ICE EXTENT V&IR RADIOMETER ~5km ~5 ~5 36h MICROWAVE RADIOMETER 10 -15km 10-15 10-15 36h IMAGING RADAR ±25m 25 m l/14dNEAR CONTINENTAL U.S. LEADS >50m ±25m 25m ICEBERGS >25m ±25m 25m OCEAN FEATURES SHORES, CLOUDS, ISLANDS V&IR RADIOMETER ~5km ~S ~S 36h SHOALS, CURRENTS IMAGING RADAR ±25m 25m 25m l/14dNEAR CONTINENTAL U.S. ATMOSPHERIC CORRECTIONS WATER VAPOR & LIQUID MICROWAVE RADIOMETER ±25m SO 50 36h Figure 1-2. --Geophysical oceanographic measurement capabilities for SEASAT-A COMPRESSED PULSE ALTIMETER MICROWAVE SCATTEROMETER SYNTHETIC APERATURE IMAGING RADAR MICROWAVE RADIOMETER VISIBLE AND INFRARED RADIOMETER GLOBAL OCEAN TOPOGRAPHY GLOBAL WIND SPEED AND DIRECTION WAVELENGTH SPECTRA GLOBAL ALL-WEATHER TEMPERATURE GLOBAL CLEAR-WEATHER TEMPERATURE GLOBAL WIND AMPLITUDE GLOBAL FEATURE IDENTIFICATION GLOBAL WAVE HEIGHT LOCAL HIGH RESOLUTION IMAGES GLOBAL ATMOSPHERIC PATH CORRECTIONS 13.9 GHz 13.9 or 14.595 GHz 1.35 GHz 6.6,10.69,18, 22.235, 37 GHz 0.52-0.73 Mm 10.5-12.5 Mm l-m PARABOLA 5-2.7m STICK ARRAYS 14 X 2m ARRAY 0.8-m OFFSET PARABOLA 12.7 cm OPTICS 2.5-kWPEAK 125-W PEAK RF 800-W PEAK ±20-25 deg CROSS SCAN 360-deg SCAN 125-W AVE 165-W AVE 200-250W AVE SOW lOW ~8 kb/s 2 kb/s 15-24mb/s 4 kb/s 1 2 kb/s SKYLAB/GEOS-C SKYLAB APOLLO 17 Nimbus -G ITOS Figure 1-3. — SEASAT-A sensor characteristics 1-4 A limitation is placed on the SAR data acquisition compared with the other sensors because of its high data rate of about 100 million bit/s and the orbital parameters. Data from SAR will not be recorded onboard but will be directly readout at Fairbanks, Ak., Goldstone, Ca. , Rosman, NC, and St. John, Newfoundland. All the coastline of the United States, however, will be covered, the exception being Hawaii. Other SAR data capabilities and constraints are described in appendix A. 1.4. SEASAT-A Experiment Teams Each of the five sensors on SEASAT-A has a NASA/JPL experiment team responsible for instrument verification, validation, and continuing performance evaluation. The experiment teams will be highly interactive with the mission planning. The following are the NOAA scientists on these teams. Altimeter B. Chovitz NOS M. Byrne ERL Scatterometer L. Baer NOAA Hdq. Radar J. Sherman NESS D. Ross ERL C. Rufenach ERL Microwave D. Ross (Chairman) ERL radiometer J. Alishouse NESS As structured, it is only through the exper- iment teams that special data acquisition and processing can be accomplished during the mission. l.S SEASAT Follow-On Systems Potential follow-on systems are being con- sidered by NASA at both the project level at JPL and the program level at headquarters. NOAA will support the updating and revision of the program development plan of the Earth and Ocean Physics Applications Program (EOPAP) of NASA for which SEASAT-A is a part of the overall plan, but currently is unable to better define its marine requirements beyond those originally submitted for SEASAT-A, Nimbus-G, TIROS-N, and LANDSAT. NOAA will evaluate the data from SEASAT-A in terms of instrument capabilities to ad- dress NOAA requirements and information needs before attempting to specify the oper- ational characteristics. A major portion of the NOAA effort planned after May 1979 is a systems integration study of oceanic as well as meteorological requirements to define NOAA operational environmental data collection systems for the mid-80s. VIR P. McClain (Chairman) NESS 1-5 SECTION 2. SCOPE AND GOALS The mission of NOAA is to: # Explore, map, and chart the global ocean and its living resources. # Manage, use, and conserve those res- ources . 9 Issue warnings against impending de- structive natural events. 9 Describe, monitor, and predict con- ditions in the atmosphere, ocean, Sun, and jipace environment . # Develop beneficial methods of environ- mental modification. # Assess the consequences of inadver- tent environmental modification over a period of time. For establishing a close tie between the potential data and information derivable from the SEASAT-A system, the mission of NOAA will be addressed through the appropri- ate Major Line Components (MLCs) of NOAA. The SEASAT-A system is a unique platform in that it is the first space system to address needs within all of the NOAA components, and the PDP is structured accordingly. The scope of the overall mission and ob- jective structure is summarized in figure 2-1. It is not all inclusive with regard to the total MLC objectives, but is tailored to MLC objectives to which the SEASAT-A system can provide data and information. The mis- sion statements in figure 2-1 are an abbrev- iated form of those previously cited. The role of the National Environmental Satellite Service (NESS) supports the requirements of and serves the other MLCs. Historically, this support has been primarily through the National Weather Service (NWS) , with ar- chiving by the Environmental Data Service (EDS) . Figure 2-1 illustrates the NOAA mission relationships to SEASAT-A applications as well as the prime MLCs associated with each mission task. The figure does not illus- trate the significant interplay and cooper- ation between the MLCs in satisfying the NOAA mission. Additionally, the PDP is structured similarily to figure 2-1 in that, though NESS is the manager and coordinator of the NOAA SEASAT effort, most of the ap- plications will be by the appropriate MLCs. 2-1 MISSION PRIME MLC MLC OBJECTIVES EXPLORE, MAP, CHART NOS, NMFS, MANAGE, USE, CONSERVE NMFS WARNINGS DESCRIBE, MONITOR, PREDICT NWS, ERL, EDS BENEFICIAL WEATHER MOD ERL INADVERTANT WEATHER MOD CONSEQUENCES ERL, EDS NOS GEOID MAPPING & TIDE MODEL NMFS RESOURCE MANAGEMENT ALLOCATION & REGULATION NWS FORECAST & WARNING OF MARINE WEATHER ERL BASIC RESEARCH ON ATMOSPHERE, OCEAN, SUN & SPACE ENVIRONMENT EDS DATA ARCHIVING & DISTRIBUTION,* CLIMATE STUDIES L NESS ENVIRONMENT SATELLITE TECHNIQUES DEVELOPMENT &OPS SEASAT - A DATA & INFORMATION CAPABILITIES INERTIAL COORDINATES, GEOPOTENTIAL FIELD, MEAN SEA LEVEL MAXIMUM SUSTAINABLE YIELDS, RESOURCE SURVEYS, INVIRONMENTAL INDEXES, MARINE WEATHER FORECAST, VESSEL SURVEILLANCE SIGNIFICANT WAVE HEIGHT, SURFACE WINDS, SURFACE TEMPERATURE, ATMOSPHERIC LIQUID WATER VAPOR, SEA & LAKE ICE SELECTED ENVIRONMENTAL & GEODETIC DATA ALL ENVIRONMENTAL & GEODETIC DATA, HEAT BUDGET DEFINITION OF OPERATIONAL REQUIREMENTS, INSTRUMENT ASSESSMENT BENIFITS Figure 2-1.--N0AA mission relationships to SEASAT-A data and information 2-2 SECTIONS. BENEFITS If SEASAT performs as planned, data will be available (particularly for the data- sparse marine areas) to improve and upgrade services and products provided by NOAA, Accordingly, benefits can accrue to both NOAA in the form of an improved data collec- tion system (noting that SEASAT is consid- ered only a part of an observation system) and NOAA customers in the form of more effi- cient and safe operations due to more accu- rate and reliable information. Benefits of significant substance, how- ever, can be expected only when SEASAT is functioning routinely and continuously and the data are fully integrated into ongoing programs. This implies an operational SEASAT system. SEASAT-A, therefore, mainly is expected to provide the data for the re- quired research and demonstration to assess the applicability and utility of these data to requirements. The experiments contained within this PDP are directed toward making this assessment as well as immediate appli- cations where possible. Decision on the benefits to be derived from SEASAT, there- fore, is one of the results expected from the activity outlined in the PDP. In the interim, the best available infor- mation on the benefits expected from an op- erational SEASAT system is contained in reports prepared by ECON, Inc. (1975),* on behalf of NASA. The results of these re- ports are summarized in paragraph 5.1. Inas- much as a substantial portion of the bene- fits compiled in the ECON study depend on assumed improvements in weather forecasting, the rationale for these assumptions is dis- cussed in Volume II of the ECON study in a section entitled "Simulation Experiments to Quantify the Impact of SEASAT Data on Short Term Weather Forecasting" prepared by Dr. Isadore Halberstran of the Jet Propulsion Laboratory. In addition, several areas that are read- ily identifiable as benefits based on some of the experiments in the PDP are discussed in paragraph 5.2 and with the individual ex- periments detailed in appendix B. 3.1. Summary of NASA Benefits Studies Two benefits studies related to opera- tional SEASAT systems have been conducted by NASA. The initial study of the potential economic benefits was conducted during FY 1975. The results, reported in "SEASAT Economic Assessment" (ECON, Inc., 1974),** identified benefits from four of the appli- cation areas studied. These were: Optimum Track Ship Routing ($28M, $32M, and $36M in 1978, 1992, and 1995, respectively); Iceberg Reconnaissance ($5M in 1985 to $8M in 2000) ; Sea-Leg of the Trans-Alaska Pipeline ($6M- 7M initially to $1M by 2000 because of oil depletion) ; and Offshore Oil and Gas (North Sea example, $85M to $210M annually). All figures are in 1975 millions of dollars. The second, more detailed study conducted by ECON, Inc., during FY 1976 was directed toward confirming the benefit estimates in the three areas identified previously and also identifying other areas of application benefits. This study (Econ, Inc., 1975) provided an in-depth analysis of seven areas of civilian maritime activity and an evalua- tion of operational SEASAT system costs. The cumulative civilian benefits reported by this study range from $802M to $270M (1975 dollars) at a 10% discount rate. A summary of the specific cases is given in table 3-1 and outlined below: Offshore oil and natural gas. Two sepa- rate activities were treated in these case studies: (1) production platform erection and (2) pipelaying and exploratory drilling. The prime factor in these case studies was the determination of the influence that im- proved weather and sea condition prediction could have in reducing economic losses. Operational data were used from industry experience in the North Sea prior to 1971 and in the Gulf of Mexico off the Louisiana coast in 1972 for oil production and pipe- laying and from drill ship operations in the Celtic Sea during 1970-74 for explora- tory drilling. *ECON, Inc., "SEASAT Economic Assessment," Report Nos. 75-125-1A--10A, 10 vols., NASA (National Aeronautics and Space Administra- tion) Contract No. NASW-2558, Princeton, N.J., Aug. 1975. **ECON, Inc., "SEASAT Economic Assessment," Report Nos. 74-2001-11, 1 vol., NASA (Na- tional Aeronautics and Space Administration) Contract No. NASW-2558, Princeton, N.J., Oct. 1974. 3-1 Based on the assumption of highly precise short-range (24-48 h) weather and sea state forecasts, benefits for production plat- forms, pipelaying, and exploratory drilling are derived from lower contractual costs by reducing nonproductive labor and accidents. In Econ, Inc. (1975), the study conducted by Battelle was substantiated by an inde- pendent study conducted by the Canadian Centre for Remote Sensing. Arctic operations. Identified benefits are based on assumption (per projection by MARAD) of tanker operations from Alaska by northwest passage to east coast ports, at- tributable to improved ice data and forecasts. The study assumes that significant oil and gas resources will be found in the North American Arctic regions and that the produced fuels will be transported by tanker to east coast ports during the peri- od 1992-2000. Improved ice information and forecasts, primarily through the use of the Synthetic Aperture Radar (SAR) , are antici- pated to facilitate transit through the ice and avoid costly delay and damage. The SAR will permit "all weather" data gathering on location of thinner (winter) ice areas, lo- cate weakness areas (through cracks), and Table 3-1. --Summary of most likely range of benefits exclusive to SEASAT* Industry or sector Integrated benefit + Offshore oil and natural gas 214- 344 Ocean mining (Not estimated) Coastal zones 3- 81 Arctic operations 96- 288 Marine transportation 215- 525 Ocean fishing 274-1,432 Ports and harbors 0.5 Total 802-2,670 *From Econ, Inc. (1975), "SEASAT Econom- ics Assessment: Volume I, Siommary and Con- clusions". tMillions of 1975 dollars, 10% discount rate; planning horizon to year 2000. delineate formidable or impossible areas with a high degree of reliability. Ocean fishing. Benefits in this area were identified for improved productivity assessment and operations safety as a re- sult of improved weather and ocean fore- casts. Various elements of the U.S. commercial fishing industry were investigated to assess the economic benefits that might accrue from data provided by an operational SEASAT system. Two aspects were studied: production and sea damage. The fisheries studied were gulf shrimp, tuna, salmon, men- haden, and Atlantic groundfish. These pro- duced about 60% of the total volume and 53% of the total dollar value of U.S. landings in 1973. A conclusion was that SEASAT data could provide only limited assistance to the pro- duction end of the U.S. fisheries examined. Tuna and menhaden were the only fisheries that showed any production benefits. In this area, benefits could result if under- utilized species or new fishing areas were discovered (e.g., menhaden). Consideration was also given to prediction of productivity based on improved surface wind data and de- velopment of upwelling areas. The case study involving sea damage showed that fishing vessel casualties, cargo loss, and death or injury could be reduced with improved weather and sea state information. Marine transportation. Benefits were es- timated for three cases including U.S. trade routes: dry cargo, sea-leg trans-Alaska pipeline, and worldwide tanker operations based on improved optimum track routings. The SEASAT ocean condition data and re- sulting forecasts could be usefully employed to route ships around storms and provide benefits by reducing time delay on all U.S. trade routes and reducing hull damage, ma- rine insurance costs, and catastrophic losses. Three future systems were considered using data for the North Atlantic trade route 05 (United Kingdom, Ireland). The three sys- tems considered the present system (no change to 1985-2000) ; modified present system--uses advances in forecasting science and data collection for 1985-2000; and the SEASAT-aided system--normal advances plus further improvement in data collection for 1985-2000. Coastal zones. The study considers the impact of reliable, accurate, and timely predictions of the time, location, and dura- tion of destructive coastal zone phenomena. On the basis that a perfect prediction would encourage protection of life and property and increase the effectiveness of relief following the event, avoidable losses are 3-2 computed. Data introduced by an operational SEASAT and previously unavailable as to scope, quality, and frequency are factored into the study to compute expected improve- ment in information and reduction in avoid- able losses. Ports and harbors. The study shows a very small benefit based on improved precipita- tion forecasts for assisting in management decisions regarding berthing and offloading ships in U.S. ports. The study examines weather-dependent ac- tivity in harbors and ports of the United States, using the port of Philadelphia as a base. The consequent avoidable costs in- curred by inaccurate or unused weather data and forecasts were determined. The conse- quence of introducing SEASAT data for im- provement of precipitation forecasts during 1985-2000 was calculated and found to be re- latively small because of the judgment that SEASAT data will have little impact on the complex problem of precipitation predictions of the type required to afford owners cer- tainty of decision. Ocean mining. This was not estimated be- cause of the nature of the operations and the secrecy surrounding them. The industry consists of two basic parts: (1) near-shore mining--well established, competitive, and surrounded by operational data secrecy and (2) deep sea mining that is being created. Deep sea mining, being in its formative stages, lacks operational ex- perience and limits derivation of substan- tive benefits. Of course, operations are limited because of weather and sea conditions; thus, any improvement in description and prediction services to these industries is expected to result in more efficiant operations, lower operating cost, and fewer losses. 3.2. Improvements in Existing Services Observations of sufficient scope, distri- bution, and frequency are fundamental to improving environmental analysis and fore- casting services. Currently, observations for marine areas are concentrated primarily along the well-traveled shipping routes or obtained intermittently during special in- tensive surveys. With the exception of cloud information, sea ice, sea surface temperature, and atmospheric sounding data obtained by the operational NOAA satellites, most of the global oceans are not routinely monitored to obtain measurements. The mi- crowave sensors of SEASAT-A will provide data on surface wind fields, waves, storm surge and setup, surface temperature, cur- rents, sea and lake ice, geoid, tides, and ocean pressure gradients unobscured by clouds or light conditions. During the SEASAT-A experiment and demonstration peri- od, observational data equivalent to about 20,000 ship reports per day (surface wind) distributed globally will be obtained. The yet-to-be-defined operational SEASAT pre- sumably would produce an even greater number of observations and cover current "holiday" (data-sparse) areas. This increase in areal and temporal observational data is expected to contribute to improving description and prediction services in marine meteorology and oceanography. Services provided in fisheries, such as porpoise protection imposed by court order in 1976, are also expected to benefit not only from improved environmental data but also by monitoring fishing activity in the vast new area of jurisdiction to be imple- mented early in 1977. Obtaining improved data on the geoid will contribute directly to defining a standard reference surface for the oceans that will enhance derivation of currents, sea slope, ocean tides, and sea state. There are also some prospects for deriving gravity anom- alies in selected ocean areas that might serve as a basis for geophysical prospecting as on land. Also, the altimetry data from SEASAT are expected to provide measurements of sufficient accuracy to help resolve the current discrepancies in sea level between steric measurements (calculated from the density field) and spirit leveling along the coasts. We must emphasize that one of the objec- tives of the experiments to be conducted with SEASAT-A is to assess the impact of these new data on NOAA services and products and to assign quantitive values to the bene- fits. SECTION 4. TECHNICAL PLAN The application of SEASAT-A capabilities (section 1) can result in potential benefits (section 3) derived through a set of experi- ments in which advanced in situ measurement techniques are conducted in concert with SEASAT-A (and Nimbus-G) overflights. Air- craft and other satellite data will supple- ment and augment these data such that both surface and remotely acquired data can be fully interpreted. Experiments will be con- ducted on local, regional, and global scales. Specific experiments will quantita- tively define the response of microwave en- ergy to the ocean surface, and others will emphasize the application of satellite data to immediate NOAA problems. This section defines the NOAA technical program to be conducted during the 1978-80 time period. Preparation for Nimbus-G and SEASAT-A has been continuing and must con- tinue until time of launch so that an inte- grated set of experiments can be conducted. An overview of planned activity, including the approach and milestones for accomplish- ment, is followed by the details of experi- ments proposed for SEASAT-A and Nimbus-G studies. 4.1. Overview of Planned Activity Two main components of activity are planned: research and operational demon- stration. Research will receive primary emphasis during the first six months of sat- ellite life with increased emphasis on oper- ational demonstration experiments during the second six months. During the research phase, considerable attention will be given to the correlations between directly meas- ured surface data and the satellite data for purposes of quantitative definition. The operational demonstration phase will be con- cerned more with the quality of the satel- lite data. Except for the operational demonstration proposed by NWS for global analysis of sur- face winds, surface temperature, and signif- icant wave height, all experiments will be conducted using the satellite data in a non- real-time mode. All non-real-time data will be archived and distributed by the Satellite Data Services Branch (SDSB) of EDS which will be block funded to support the approved NOAA experiments. All other data users. whether NOAA or non-NOAA, will receive the data in the routine manner of reimbursement. The data in this non-real-time archive will be that processed by the Jet Propulsion Laboratory (JPL) . (See also figure 1-21.)* A decision is yet to be made on whether to archive the real-time data used by the Na- tional Meteorological Center (NMC) of NWS. An overview of the SEASAT-A planned activ- ity and its relationship to the NOAA program and budget structure is shown in figure 4-1. The matrix illustrates by solid circles those SEASAT-A experiments that directly relate to the NOAA mission and by open circles those that support NOAA activities. The matrix also shows that the planned NOAA SEASAT-A activity applies to just over 20% of all NOAA programs and offers a unique opportunity to quantitatively assess the benefits derivable from satellite supported systems. This 20% factor excludes the two categories dealing with satellite develop- ment; if these were included, the NOAA SEA- SAT activity would be applicable to more than 25% of the total NOAA program. 4.1.1. Summary of Research The research activity is a multifaceted set of experiments that will interact with ongoing NOAA, national, and international programs. The interaction will serve these programs as well as those specifically pro- posed for support within this PDP. Basic observations using in situ techniques will be carried out on local scales (up to hun- dreds of kilometers) which may support larger scale activities. Thus, local exper- iments may form elements of "ocean truth" for larger scaled experiments. These larger scale experiments may be regional in nature (up to thousands of kilometers) or global. For example, surface wind data may be ob- tained locally from surface and aircraft platforms for verification and calibration of systems performance of SEASAT/Nimbus data to be used in support of such programs as FGGE on a global basis. The manner of the coupling of discipline areas with scale sizes, the MLCs involved, the major programs, the research elements, and specific experiments are shown in fig- ure ES-2. Each element is discussed more fully in paragraph 4.2 and appendix IV. "See appendix I 4-1 «<,> >. 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E s? „, S "« ■>oo c 3 g "? 1 1 is > II o _l °-f "s-S 5 5||6 ^« r ^ s UJ "- en 4-2 4.1.2. Sunimary of Operational Demonstra- tions The operational demonstration is focused in four areas of application including liv- ing marine resources, meteorology, oceano- graphy, and geodesy. An added element of the demonstration program is to define the operational requirements for environmental satellites in the mid-80s. This will not require field analysis in itself, but will draw on the other research and demonstration elements. Figure ES-3 summarizes the basic activity planned for operational demonstration. The demonstration activity is sharply focused on specific problem areas relating to immediate and near-term needs of NOAA. In addition, the demonstration program contains a study of future operational systems based on actu- al satellite capabilities. This last ele- ment of study, when combined with the veri- fication of benefits potentially derivable from satellite systems, will allow instru- ment priorities to be established on a cost/ benefit basis; namely, how NOAA can best al- locate satellite funds. 4.1.3. Milestones The programmatic milestones necessary for the accomplishment of the technical plan are tabulated in table 4-1. A major interface must be maintained with NASA to support these milestones and insure successful com- pletion of joint experiment activity. 4.2. Activity Plan The activity proposed for SEASAT-A exper- imentation and operational demonstration is prepared as a total NOAA program rather than individual elements assigned to each MLC. A detailed experiment plan is available in draft form which describes the individual MLC programs. It will parallel this section with regard to section numbering. Further, the section numbering system will be used throughout the NOAA SEASAT-A Program to i- dentify experiments. Thus, Experiment No. IV. 2. 1.1. 3 (appendix IV) will be those re- search studies of Continental Shelf/Near- shore Circulation Processes, an element of the Studies of the Coastal Zone and Lakes. 4.2.1, Research The SEASAT-A research tasks that must be established or conducted fall into two cate- gories: (1) projects that relate the mea- surements taken from the spacecraft to pro- cesses taking place in and on the sea, 4.e., understanding and quantifying the functional relationships between the received signals and quantities such as wave height, sea tem- perature, etc.; and (2) the use of those calibrated and verified measurement techni- ques in oceanic and atmospheric research both ongoing and peculiar to SEASAT-A. One of NOAA's prime tasks will be to pro- vide expertise in the environmental sciences and capabilities for surface measurement which complement NASAs space science and re- mote sensor capabilities. Thus the problem of measuring oceanic and atmospheric quanti- ties on the surface in conjunction with air- craft and spacecraft overpasses becomes a task that NOAA is well equipped to perform. It is one, however, that will demand many resources and considerable time before the measurements made from SEASAT-A will be un- derstood and quantified before application to other experiments. The verification and calibration experi- ments will be conducted jointly with NASA. The experiments will be cooperatively de- signed so that satellite data and processing are provided by NASA and surface measure- ments and analyses are provided by NOAA. Joint interpretation and performance evalu- ation will establish the quantitative rela- tionships. In choosing programs in which investigations are to be carried out, maxi- mum use will be made of existing programs and resources. Thus, much can be done from ships and aircraft on a "ride-along" basis; meteorological observations, data buoys, and other NOAA environmental satellites can be used in support of SEASAT-A with only modest impact on their schedules; and the large flow of information on ocean, atmos- phere, and ice derived from concurrent re- search can be utilized because many SEASAT-A scientists are also investigators in these other programs discussed in paragraph 4.3, "Interface With Other Programs." For technical reasons, it is convenient to divide the research effort into several parts, not necessarily mutually exclusive. The parts are (1) studies of the coastal zone and lakes, (2) open ocean studies, (3) geodetic studies, (4) polar observations, and (5) experiments in hydrology. Each ex- periment to be conducted under these studies is described in more detail in appendix IV. An important ingredient in the research program is the relationship between the many research activities. The complex sea-air interaction system cannot be conveniently divided into independent studies of wind, waves, circulation, storm surge, etc., al- though the end products can be resolved. The strong coupling (solid circles) and the partially dependent coupling (open circles) between the research experiments are illustrated in figure 4-2. It is neces- 4-3 Table 4-1. --Major SEASAT-A PDP milestones 1976 June -------- -NOAA approval of PDP. August ------- -Draft of Experimental Plan. December ------ -Publication of Experiment Plan. December ------ -Identification of principal investigators. 1977 March -------- Coordination of Experimental Plan with NASA completed. May --------- Annoiincement of Opportunity for SEASAT-A participation. July -------- -Establish formal coordination with FGGE. July -------- -Deadline for SEASAT-A proposal submission. July-August ----- Proposal review and evaluation. September ------ Selection recommendations and approval of proposals. November ------ -Initiate awards of selected proposals. 1978 January ------- Finalize initial algorithms. April -------- Complete awards of selected proposals. May --------- SEASAT-A launch. June-July ------ Verification/evaluation - begin archiving. July -------- -Revise/up-date algorithms. August -September - - -Initiate basic SEASAT-A experiment. August ------- -Initiate data inputs to FGGE. August ------- -Initiate real-time data to NMC/NWS. October ------- Initiate data inputs to demo experiments. November ------ -Conduct SEASAT symposium on initial results. 1979 January ------- Initiate operational systems study. May --------- Concluded experiments and demonstrations. May --------- Review status of spacecraft health. May --------- Initiate benefits definition study. August ------- -2nd SEASAT symposium. December ------ -Publish major scientific results on SEASAT. 1980 February ------ -Workshop on demonstration/application. June -------- -Publish operational demonstration results. September ------ Define mid-80 's operational system. October ------- Final report to the Administrator. PMT/NOAA. RDT/Project. Project. RDT/Project. Project/PMT. PMT/NASA. Project/PMT. Project. RDT/Project. Project/PMT. Project. RDT/Project/NASA. Project. NASA. PI/NASA/EDS. PI/RDT. PI. Project/EDS. NASA/FNWC. PI/EDS. PMT/NASA. RDT/Project/ Contract . PI. Project/NASA. RDT/MLC. PMT/NASA. Project/NASA. RDT/Project/PMT. RDT/Project. RDT/PMT/Project. Project/PMT. 4-4 c c o o t; m ra (1) 0) CC OC o "JO V <-> O £ c c (1) tA e CL, 03 •H !-i jr W) I/) O c ^H o &, -H +-> 1— t rt 03 I— ( +J 0) C h (1) B x: ■H o ^H u (U 03 g^ I/) O re Q. Ph 0) 13 o 1/1 3 4-10 stration activity and the planned SEASAT-A research program. Only in the cases of oil detection (opportvmity basis only) and hy- drologic studies will there be no follow- through or related support of the research program to the operational demonstration. 4.2.2.1. Meteorology. Wind information de- rived from the SASS and the SMMR will be used in operational atmospheric forecast models at the National Meteorological Center (NMC) in two sets of controlled data impact studies. After the data have been vali- dated, they will be tested in (1) an opera- tional, global, large-scale, atmospheric, forecast model and (2) a limited area model with a finer grid designed to produce fore- casts in finer detail over shorter periods of time. Sets of control analyses and fore- casts produced from all operational data (A sets) will be compared with the sets of test analyses and forecasts produced for the same time period from the operational data set plus the SEASAT-A observations (B sets) . The sense and magnitude of the differences between the A and B sets will provide a measure of the operational value of the SEA- SAT system. 4.2.2.2. Oceanography. Wave height obser- vations from the altimeter will be used in real time to modify and extend the wave forecast guidance prepared by NMC, and the stored data will be used to verify model wave forecasts. Winds derived from SASS and SMMR will be used in controlled experiments with an operational wave forecast model. As with the atmospheric forecast models, A and B sets of analyses and forecasts will be produced for the same dates, and compared. In a similar manner, ice observations from the SAR will be added to sea and lake ice analyses prepared from the routine opera- tional ice observations yielding an A and B set of analyses for comparison. The sense and magnitude of differences between the A and B products provide a measure of the op- erational value of the SEASAT system. 4.2.2.3. Living Marine Resources. Effec- tive management of living marine resources in the new, 200-mile Extended Jurisdiction Zone depends in part upon effective monitor- ing programs and partly upon accurate envi- ronmental inputs to fisheries yield models and other related production forecasts. Effects of wind-induced turbulence on plankton distributions, and therefore on the survival of year-classes of fish larvae, will be determined by comparison of plankton and larvae distribution data in the Los Angeles Bight region with wind and sea sur- face temperature measurements from SEASAT. The all-weather temperature sensing capabil- ity of the SMMR will be employed to deter- mine sea surface temperature distribution in the normally cloud-covered Bering Sea where distribution and abundance of salmon stocks and marine mammals are significantly affect- ed by temperature. Wind driven (Ekman) transport will be derived from integration of SASS measurements for comparison with egg and larval survival data and with other known features of fishing species life cycles that affect year-class strength, rate of growth, availability, and production. 4.2.2.4. Geoid Comparisons. In order to extract the sea surface topography from the altimeter data, it is necessary to know the relation of the sea surface to the geoid dis- cussed in paragraph 4.2.1.3. The altimeter data yield only the distance to the sea sur- face. The geoid itself must be determined either indirectly by analysis, or directly by independent measurements. The most di- rect method is by gravity surveys at sea. This is impractical on a global scale, but is feasible if restricted to limited areas. Since the areas of greatest concern to the NOAA program are those parts contiguous to the continental U.S. , it is planned to ac- complish a detailed gravity survey extending out to approximately 800 km from the coasts by aggregating and analyzing available gravity data from NOAA and DOD files and by carrying out surface ship surveys to fill in gaps. The objective will be to achieve a mesh 15 minutes of arc on each side so that an ob- servation will be available in each square of the grid. 4.2.2.5. Operational Satellite System. The operational SEASAT system is defined as that system which, when combined with on- going, state-of-the-art, conventional, in situ, environmental data collection sys- tems, offers the best compromise between the capability to satisfy NOAA needs and the cost of the hardware, software, and ground support to maintain the satellite system. The "best" system will be optimized accord- ing to at least three criteria: minimum cost, maximum data utility, and minimum risk. Maximum data utility is that system which maximizes the availability and utility of data beyond the minimum-cost system (which satisfies the basic needs) to consider sec- ondary data applications or disciplines. Minimum risk is discussed at the end of this section. 4-11 The primary marine data needs of NOAA, po- tentially addressable by a SEASAT-type sys- tem, are: Surface winds Surface temperature Surface waves Sea and lake ice Circulation Atmospheric liquid water and vapor Geoid* The secondary data needs include: Storm damage assessment Hydrological applications Oceanic tides These data needs will be merged with the on-going environmental satellite operational requirements, which are primarily oriented toward meteorological data, to permit the operational satellite system to include the entire range of satellite derivable data. Marine data believed to be derivable from other satellite systems, such as the Coastal Zone Color Scanner on Nimbus-G, will be also included in this study, to satisfying various NOAA information needs, it will be necessary for a benefits analysis to accompany the conclusion of each experiment, in particular the demonstration experiments. These benefits analyses will occupy a considerable portion of the SEASAT-A activity in fiscal year 1980. When combined with the "best" operational satel- lite system(s), as defined by the three cri- teria noted above, the cost-benefits assign- able to a mid-80s operational system can be specified and the system selection made ac- cording to overall NOAA priorities. Figure 4-5 outlines the essential elements of the operational satellite systems study. This diagram contains a detailed analysis of the elements in Boxes I, J, K, L, and M in fig- ure ES-1. It should be specifically ob- served that the product of this study is a recommendation for definition of a mid-80s operational environmental system, not an op- erational SEASAT-type system. The data and information needs of NOAA will be viewed as a whole and used to establish the best mix of instruments and techniques based on cost- benefit analyses. The analyses which occur in the Operation- al SEASAT System Studies area of figure 4-5 will be modeled after the study conducted by ECON for NASA*. The essential methodology (figure 4-6) allows the operational system mix to be viewed not only on a cost-benefits basis, but also from that of the risk in- volved in each combination of possible mixes. This element of study will be led by NESS with strong support from the other MLC's, particularly NMFS and NWS. A major con- tract (s) will provide systems analysis, eco- nomic assessments risk determination, and cost-benefit tradeoffs. Requirements, in- formation needs, and benefits will be deter- mined within NOAA. The evaluation and com- parison of alternatives will consider not only the benefits, but also the associated levels of risk. As with the benefits anal- ysis, hard estimates on risk will be deter- mined within the SEASAT-A sensor evalua- tions. When coupled with the remaining ele- ments of the study, it will be possible to define a minimum-risk operational system as the final evaluation criterion. 4.2.3. Data Handling The Satellite Data Services Branch (SDSB) of EDS's National Climatic Center (NCC) will archive and distribute SEASAT data. These data will be available for entry into the archives as soon as 10 days after acquisi- tion from the satellite. The imagery data will be available in a variety of formats (contact print, positive or negative trans- parency, etc.) other than the archival form described below. The digital data will be provided on 9-track, 800 or 1600 BPI com- puter-compatible tapes (CCT) . Charges for these data will be made basically to cover the cost of reproduction. Block funds al- located within the PDP will be used to sup- port the approved NOAA experiments des- cribed elsewhere in this PDP. It is explicitly assumed, in defining the archiving and distribution roles of NOAA for SEASAT-A data, that all data will be in geophysical units. An exception will be the *Geoid requirements may be satisfied solely by SEASAT-A. *Vol. 10, SEASAT Economic Assessment, "The SATIL 2 Program: A Program for the Evaluation of the Costs of an Operational SEASAT System As a Function of Operational Requirements and Reliability," ECON, Inc., Contract No. NASW-2558, Oct. 31, 1975. 4-12 r 1 Experiment Evaluation ■ Ships - Buoys - Aircraft - Balloons Section 4.2.1/PDP U Data Requirements Definition Demonstration Benefits Information Requirements Definition Section 4.2.2/PDP Satellite Sensor Evaluation Operational Satellite Cost - SEASAT-A - NIMBUS-G - TIROS-N - GOES - Other Alternate Systems Operational SEASAT Systems Studies Sensors Platform Launch On-Board Processing Software Data Relay Ground Support Sensors Platform Deployment Telemetry Software Ground Support Systems Cost Mid-80s Operational Environmental System Definition Figure 4-5. --Performance and benefits study for a mid-80s operational environmental system. 4-13 Information Requirements Spacecraft Analysis Reliability Analysis Figure 4-6. --Systems analysis methodology and decisionmaking. 4-14 SAR system. No resources or facilities have been included that permit processing from engineering to geophysical units. There also remains a question, on the part of the NASA SEASAT-A Project, as to whether all data will be processed from all sensors (again, SAR is an exception) or whether the data will be processed and re- duced on a demand/request basis. Orbital Swaths: 25 x 25 cm negatives Format: N. Hemisphere daytime visible and IR on one negative, S. Hemisphere daytime visible and IR on one negative, and N. and S. Hemisphere nighttime IR on one negative. Quantity: Approximately 40 negatives per day. SAR Tape Products Scanning Multichannel Microwave Radiometer (SMMR) --Latitude, longitude and time lo- cated geophysical data of surface wind speed (no direction), sea surface tempera- ture, and integrated air column liquid water and vapor - 1 tape per day . Scatterometer--Latitude, longitude, and time located geophysical data of surface wind ve- locity - 1 tape per day . Altimeter--Latitude, longitude and time lo- cated geophysical data every 18 km along spacecraft track of the displacement of the spacecraft from the ocean surface and wave heights - 1 tape per day . Synthetic Aperture Radar (SAR)--A limited number of SAR images will be available on CCTs from this system. It will take approx- imately 4 tapes per minute of data collec- tion. Orbital Swath: mined. Negative size to be deter- Visible and IR Radiometer (V ^ IRR)--A lim- ited number of CCTs containing earth- located, time-oriented ocean radiance values will be available from this system - 1 tape per day . [Further analysis of data rates, data coverage (N.H. or S.H. only) and pack- ing density may permit more than one day's data on one tape for some of these instru- ments. ] Format: The desired product will be such that it preserves the 25 m resolution and an image size of 100 km square. Details on this are yet to be resolved. Quantity: Current plans call for only 260 passes to be processed during a one-year period. SMMR- -SMMR imagery in 105 mm color negative, positive transparency, or 25 x 25 cm black and white negative will be available from either SEASAT or Nimbus-G in the following formats and frequencies. Sea ice (horizontal polarization 37 GHz CH.). N. S S. polar stereographic maps, sea- sonally, monthly, and per cycle. Sea ice (vertical polarization 37 GHz CH.). N. £| S. polar maps same as above. World brightness temperature (horizontal and vertical polarization 37 GHz CH.). Mer- cator maps at same frequency as Polar maps. Snow cover, liquid water, droplet size and rainfall rate, and soil moisture on mer- cator and polar stereographic maps at same frequency as above. Potential users can obtain these data or information on prices and delivery schedules by contacting: Imagery Products V d, IRR--This two channel scanner obtains a continuous-strip image along the orbital track. The strip image obtained on each pole-to-pole, half-orbital traverse is called an orbital swath. On each full or- bital pass, the satellite obtains three image swaths: one visible and one infrared swath on the daytime half-orbital traverse and one infrared swath on the nighttime half-orbital traverse. Satellite Data Services Branch World Weather Building, Rm 606 Washington, D.C. 20233 Phone 301/763-8111 4.3 Interface with Other Major Programs The launch of SEASAT-A is scheduled to coincide with many major NOAA, national and international oceanographic and atmospheric research programs. The additional use of the environmental satellites planned for this period (GOES, TIROS-N, and Nimbus-G) 4-15 will provide the best synoptic view of the sea-air interaction phenomena yet provided to any major ocean-atmosphere program. Paragraph IV. 3 of appendix IV establishes the mutual benefit relationships between SEASAT-A and the NOAA, national, and inter- national programs and briefly describes the activities and data needs of these programs. These relationships are an important aspect of the NOAA SEASAT-A Program. It is more important here to show the direct and sup- portive relationships of the SEASAT-A re- search and demonstration activities to these major programs. Figure 4-7 summarizes the NOAA SEASAT-A activities which directly or indirectly support major program activity. SEASAT-A activity is relevant to about 30% of the total information required by all major NOAA, national and international pro- grams . The major programs will collect consider- able data and information needed by the SEASAT-A program, especially during the ver- ification and calibration phases, and will be representative of the major geographical areas and features associated with the ma- rine environment. Thus, the capabilities and limitations of the space sensors can be tested over a range of environmental condi- tions rather than singular or anomalous events. Conversely, satellite techniques can provide the synoptic view, but cannot totally satisfy the information needs of the marine community. 4.4. Relationship to Other Satellites During the period of activity covered by this PDP, several other satellites are planned as a continuation of the NOAA oper- ational satellite program (TIROS-N and GOES) or the NASA Research program (LANDSAT, NIMBUS-G, and GEOS-3). Although not dedi- cated to oceanographic measurements, these satellites will contribute data which will be employed in the SEASAT-A experiment pro- gram. 4.4.1. TIROS-N This is the prototype of the next genera- tion of polar-orbiting operational satel- lites scheduled for launch early in 1978. The operational system will include two sat- ellites in orbit, simultaneously, to provide global coverage and system reliability. The TIROS-N sensor package will include a new 4-channel scanner, the Advanced Very High Resolution Radiometer (AVHRR) which is ex- pected to improve sea surface temperature data and provide for improved snow/ice/ cloud/water discrimination. It will have spectral ranges of 0.S5-0.9 ym (cloud map- ping), 0.725->1.0 ym (surface water discrim- ination), 10.5-11.5 ym (thermal mapping), and 3.55-3.93 ym (thermal mapping). A fifth channel between 11.5 and 12.5 ym is planned for a follow-on system to improve thermal mapping. Data will be available in four modes: 1) direct readout to Automatic Pic- ture Transmission (APT) class ground sta- tions with panoramic distortion removed at 4 km resolution; 2) direct readout to High Resolution Picture Transmission (HRPT) class ground stations of all spectral channels at 4 km resolution; 3) global on-board record- ing of 4 km resolution data for central analysis; and 4) on-board recording of lim- ited, selectable portions of each orbit at 1.1 km resolution. In addition TIROS-N will have improved atmospheric sounder instruments and a Data Collection and Platform Location System (DCPLS) . The DCPLS will have a capability for interrogating ocean platforms and lo- cating them to an accuracy of 5-8 km. 4.4.2. GOES The Geostationary Operational Environ- mental Satellite (GOES) system, which is fully operational, provides frequent (every 20-minutes) visible (0.55 ym) and thermal (10.5-12.5 ym) imagery of the ocean areas 60°N to 60°S adjacent to the United States* with a resolution of about 1 km and 8 km, respectively, using the Visible/Infrared Spin Scan Radiometer (VISSR) . These data will provide correlative data for use in SEASAT experiments as well as assisting in planning data collection, particularly with aircraft. GOES also has a Data Collection System (DCS) which will facilitate relay of data from ocean platforms. 4.4.3. LANDSAT Multispectral data from the LANDSAT sat- ellites provide high spatial resolution imagery that may be of some correlative value when used together with SEASAT data. Coverage from LANDSAT is restricted to a narrow (180 km) swath beneath the satellite such that an area receives repeat coverage every 18 days. Since the orbits of SEASAT and LANDSAT are far from coincident, little benefit is expected by incorporation of *Global coverage may be available since both Japan and USSR plan to place geosta- tionary satellites in orbit in the time frame covered by this PDP. It is. presumed that the sensors will be similar to GOES. 4-16 u o r—^ nl . e W i= o CT) 4-> ^ W) ■M o C u cj ft > cu o 1— t •H flj in ^H 0) ji: t/5 u. OJ 1/) H o +J s 4-> T3 o C CO CtJ < O 1 •H H < &( C/1 c8 < ^H PJ M CO O C < oj 50m ±25m 25m ICEBERGS >25m ±25m 25m OCEAN FEATURES SHORES, CLOUDS, ISLANDS V&IR RADIOMETER ~5km ~5 ~5 36h SHOALS, CURRENTS IMAGING RADAR ±25m 25 m 25m l/14dNEAR CONTINENTAL U.S. ATMOSPHERIC CORRECTIONS WATER VAPOR & LIQUID MICROWAVE RADIOMETER + 25m 50 50 36h Figure 1-6. --Geophysical oceanographic measurement capabilities for SEASAT-A. COMPRESSED PULSE ALTIMETER MICROWAVE SCATTEROMETER SYNTHETIC APERATURE IMAGING RADAR MICROWAVE RADIOMETER VISIBLE AND INFRARED RADIOMETER GLOBAL OCEAN TOPOGRAPHY GLOBAL WIND SPEED AND DIRECTION WAVELENGTH SPECTRA GLOBAL ALL-WEATHER TEMPERATURE GLOBAL CLEAR-WEATHER TEMPERATURE GLOBAL WIND AMPLITUDE GLOBAL FEATURE IDENTIFICATION GLOBAL WAVE HEIGHT LOCAL HIGH RESOLUTION IMAGES GLOBAL ATMOSPHERIC PATH CORRECTIONS 13.9 GHz 13.9 or 14.595 GHz 1.35 GHz 6.6,10.69,18, 22.235, 37 GHz 0.52-0.73 /im 10.5-1 2.5 Mm 1-m PARABOLA 5-2.7m STICK ARRAYS 14 X 2m ARRAY 0.8-m OFFSET PARABOLA 12.7 cm OPTICS 2.5-kW PEAK 125-W PEAK RF 800-W PEAK ±20-25 deg CROSS SCAN 360-deg SCAN 125-W AVE 16S-W AVE 200-250W AVE SOW low ~8 kb/s 2 kb/s 15-24 mb/s 4 kb/s 12 kb/s SKYLAB/GEOS-C SKYLAB APOLLO 17 Nimbus -Ci ITOS Figure 1-7. --SEASAT-A sensor characteristics. 1-4 X V w u 3 o ra = 1 o _. s c: E 8 9- ^ '^ H, 8 I !K £^ rN -^ ,^ UJ s § '^ i ^ - k^ 5 E — o ui O 8 fo i !i: .^ ir\ ^ _ £K CSI ETER ( ADAR E RAD OMETE nEROM GING R ROWAV R RADI < < o — ■Li o s :? ^ < i/> — s > 1 'M r: < 0) f-l DO 1-5 {«? > z OL < ff (9 O Q. o cc O o u UJ D N I 9 I- K V lU - I K +1 > +1 H < g 5k*^ ^ rj *" "= "1 g w f .. -J o uj ifl O lu ,- ir M 2 > +1 < +1 CO vP QJ fc ^ t s s 5 HI j; O ^ Els u CO Gc e S < w S oc m O lu < UJ UJ -J > (J UJ < < oc St* O tc - oc 3 il 3 o UJ >« ^^ l2 CM tn +1 M M z o u oc oc o u u oc Ul z Q. (/) lU 51 Ul K H- < CO j£ oc 5 H % O UJ 2 N S UJ . 5S = < < o tc u- "; o > u Cfl e m " J< in v> — C u s z UJ S UJ oc 3 -, i i> 8 > J J o E .1. H B g B B S » P. 5 en < Hi 3 00 1-6 l.4r 1.2- 3|3 b| b CM " l.O .t .8- ^ .6- §' .4- < .2- Trailing edge; decay time determined by antenna beamwidth Leading edge rise time determined by roughness ! hh \. 1.6 m(Hi,3- 4.5 m, W* 10m/sec> 'h ■ 3.6 m •H <4-| o c o to •H nJ g' o u 3 60 1-8 .1 .08 A June 5, 1973 (Hurricane Ava) O June 6, 1973 D June 11, 1973 u C/3 .008 - .006 - .004 - .002 - .001 5 6 7 8 9 10 Windspeed, m/sec 20 *Resolution has direct impact on NOAA potential operational systems, since it is highly desirable to avoid two instruments to serve as anemometers. 40° NADIR ANGLE -6 p ~-7.48db -8 - / / \ ~ -9.62 db > -10 rTlj-i J L 1 > > to -12 - -* \ 1 J -L - -13.42 db -14 DOWNWIND UPWIND -16 , 1 1 1 1 1 1 1 1 1 1 90 180 270 360 Azimuth Angle (Degrees) J Figure 1-13. --Radar backscatter as a function _Q of azimuth angle for a 12.86 m s"^ windspeed measured by the Langley AAFE RADSCAT program. Figure 1-12. --The S193 scatterometer response (solid line) compared to in-situ measure- ments of wind at sea, 30 days into the first Skylab mission (horizontal polariza- tion; 50° angle with vertical). sea-air interactions in heavy storms where scientific measurements can be obtained only by high risk of life and property. 1.2.3.2. Scatterometer. The SE ASM- A Scat- terometer S^ystem (SASS) will serve primarily as a low- to intermediate-surface windfield anemometer and secondarily for measurement of surface roughness. The accuracy for wind measurement is ± 2 m/s or 10% (whichever is larger) and ± 20° in angle. The SKYLAB S193 scatterometer capability, illustrated in figure 1-12, shows the potential for SASS to measure surface winds. These data also show that SASS may serve as an anemometer over high windfields as well--a point of contro- versy over the past decade that will be resolved during the SEASAT-A experiments.* Besides technical improvements in the SASS instrument over the S193 scatterometer, two other features will extend SASS capabilities over those of its predecessor. First, SASS will have two fan beams looking forward to either side of the spacecraft at a 45° ori- entation with respect to the flight path and a duplicate set of fan beams behind the spacecraft. Each area of the ocean surface observed by SASS will be seen twice with orthogonal views. This will permit the determination of wind direction to ± 20° with a 180° ambiguity. The mechanism for this is illustrated in figure 1-13 as determined from aircraft measurements. The backscatter varies not only with surface wind speed but also with the direction of observation. The second feature that will extend SASS capability is in understanding the extent of the required surface truth. Analyses of the surface winds every 30 hours over a nine-month period by City University of New York scientists (Pierson and Cardone, as yet unpublished) revealed that the variance in the in-situ data is approximately equal to the wind speed being observed. That is, an analyzed wind of 15 knots showed individual 1-9 RESOLUTION PARAMETERS FREQUENCY (GHZ) WAVELENGTH (CM) DIFFRACTION APERTURE (M) BEAMWIDTH (DEG) CROSS-TRACK RESOLUTION (KM) IN-TRACK RESOLUTION (KM) CONTIGUOUS PERIOD (SEC) NO. CELLS PER SWATH NO. CELLS MOVED PER INTEGRATION INTEGRATION TIME PER CELL (MSEC) 6.600 10.690 18.000 22.050 37.000 4.545 2.806 1.667 1.351 .811 .80 .80 .80 .80 .80 3.98 2.46 1.46 1.19 .71 92.4 57.0 33.9 27.6 16.5 144.2 88.8 52.7 43.0 25.6 22.35 13.77 8.17 6.67 3.97 9.4 14,6 23.9 29.1 48.2 1.0 1.0 1.0 1.0 1.0 150.2 92.7 55.1 45.0 26,8 SENSITIVITY PARAMETERS RADIOMETER NOISE TEMP (K) 600. 600, PRE-DETECTION BANDWIDTH (MHZ) 100,00 100,00 SIGNAL LINE LOSS (DB) 1.20 1.20 SIGNAL LINE TEMP (K) 295. 295. SIGNAL TEMP (K) 200. 200. COMPARISON LOAD TEMP (K) 295. 295. SIGNAL DTRMS PER CELL (K) .58 ,74 600, 100,00 1.20 295. 200. 295. .97 600. 100.00 1.50 295. 200. 295. 1,15 600, 100.00 2, 295. 200. 295. 1. 00 68 Figure I-14.--SMMR nominal parameters. reports of 15 knots ± 8 knots. Hence, a portion of the variance found in figure 1-12 is attributable to the surface in-situ wind errors, a portion to errors in determining the wind direction as required by figure 1-13, and a portion due to instrument errors A major advantage to the SEASAT-A wind ex- periment is that a single platform will make global measurements, thus allowing the systematic errors to be calibrated and corrected. 1.2.3.3. Microwave Radiometer. The S^can- ning Multifrequency Microwave R^adiometer (SMMR) will operate at the five frequencies shown previously in figure 1-7 and will be identical to the SMMR on Nimbus-G. There are other important characteristics of this instrument which will have a conical scan of to 50° to the right of the flight track at a depression angle of 42° (angle of incidence at the surface is 50° due to the Earth's curvature). The nominal parame- ters of this instrument are shown in figure 1-14. The Nimbus-S and -6 platforms carried 19.4- and 37-GHz scanning radiometers, respectively. The theoretical ocean response at the Nimbus-5 frequency is shown in figure 1-15 for vertical and horizontal response and will be very similar to the 18 GHz response of the SMMR. The importance of the 50° angle of incidence is apparent in this figure. First the horizontal polar- ization will be most sensitive to surface roughness; and second, the vertical polar- ization is essentially independent of rough- ness at 50°. Both polarizations are equally sensitive to water vapor, but both are insensitive to sea surface temperature. The other frequencies have similar sensi- tivities, such that 6.6 GHz (vertical polar- ization, figure 1-3) is most sensitive to temperature, 10.69 GHz to roughness, 22 GHz to water vapor, and 37 GHz to ice conditions. All frequencies will be dual polarization. Algorithms and experiments will be designed to take advantage of the unique interactions that exist at each frequency in order to fully compensate for the varying environ- mental factors . In order to be brief, the problem of the measurement of environmental factors may have been simplified to the point of imply- ing that the answer exists. However, recall that the ocean is more a reflector than emitter of microwave energy. Unlike the situation with active microwave sensors, the energy comes from many sources. In figure 1-5, a curve labeled "Radiometer Below Attenuating Medium" was included since, for a microwave radiometer operating under an attenuating medium, the energy from that medium is partially reflected from the ocean surface and introduces an error. There is actually the equivalent of a two-way loss when the radiometer operates above the medium just as for active sensors. For spacecraft, all instruments are above the medium, but the radiometer will receive energy from the atmosphere that is reflected from the surface outside the normal field- of-view of the antenna. This contaminates true observational value. The amount and frequency of occurrence of this influence will be evaluated in the SEASAT-A experi- mental program. Further, this effect shows the strong need for a multiple-sensor approach to measure the same environmental phenomena . I-IO 220 r 10 20 30 40 50 O.deg Figure 1-15. --Brightness temperature as a function of incident angle with wind- roughened ocean surface as a parameter (frequency of 19.4 GHz, water tempera- ture of 290 K) . (Top) Vertical polari- zation (windspeed of 14 m s"-*-); (bottom) horizontal polarization. 1.2.3.4. Radar. The S^ynthetic Aperture Radar (SAR) will be a new Earth observation sensor having no space heritage beyond devel- opment work for Apollo 17. Technical design for the SAR on SEASAT is also quite differ- ent from what might be found on SAR's de- signed primarily for terrestrial observa- tions. The coherent nature of a SAR allows integration in a scene to achieve spatial resolution, but the ocean is a moving system. A spatial resolution of 25 m is desired in order to image gravity waves of 50 m in wavelength, but such a wave limits the amount of integration time to around 0.6 seconds owing to the wave's physical move- ment. Discussion of the SAR technical character- istics beyond the information in figure 1-7 is beyond the scope of this PDP. Quantita- tive data will be derived primarily from imagery analysis, rather than the data itself being quantitative in terms of geo- physical units as will be the case for the other three microwave sensors. The 100 km swath-width of SAR will collect data in a direct readout mode. The data rate of 20 x 10^ bits/s prohibits on-board recording. On the average, images from the same area will be collected once every 18 days only in the vicinity of readout sta- tions. The exact orbit selection, discussed in paragraph 1-3, has not been determined, but will not change the average. As an example, the same point could appear in three consecutive days of coverage and then not be in the SAR field-of-view for about 42 days. The orbit is planned to exactly repeat every 152 days. Additionally, the SAR will look to the right side of the spacecraft track so that the orbital cover- age is plus 75° North and minus 69° South latitude. The imaging radar can function through clouds and nominal rain to provide wave patterns, high resolution pictures of sea and lake ice, oil spills, current patterns manifested by wave modification, internal wave patterns, storm damage to coast lines, and fishing vessel surveillance. The value of wave patterns by the radar cannot be overemphasized. Wave energy convergence and dissipation, wave model development and verification, two-dimensional wave (or slope) spectra, shoal detection and poten- tially the interface between fresh and saline water masses can be measured by SAR. Figure 1-16 illustrates the imagery of waves and the derivation of wave spectra from the imagery. Because wave velocity varies with ocean wavelength, the radar doppler response alters which waves are focused in the image plane (fig. 1-17). I-ll Figure 1-16. --JPL imaging radar, ocean swells, digital two dimensional intensity spectra and enhancement. 1-12 Direction of Motion Resolution Elements Elements Resolved by Range Differencies 7 Elements Resolved, by Doppler Shift +Af Range determined resolution; Doppler determined resolution; function of frequency, pulse function of hardware and data length, and angle of incidence. processing capabilities Figure 1-17. --Principles of a Synthetic Aperture Radar system. 1-13 Table 1-2. --Basic orbital characteristics Period Altitude Orbits/day Orbit repeat (exact) Inclination Global coverage Payload Oceanic Sensors 100.75 min 794-808 km non- sun-synchronous 14.3 152 days 108° ~ 36 hours for 95% Microwave radiometer, altimeter, and scatter- ometer; Visible § IR radiometer; radar 1.2.3.5. Visible and IR Radiometer. The Visible and IniraTed Radiometer (VIR) is a modified version of the scanning radiometer currently used on the NOAA (ITOS) series of operational satellites. The modification corrects for the altitude differences between the NOAA and SEASAT-A satellites and the non-sun-synchronous nature of SEASAT-A. The two channels will be used principally for feature identification. The thermal channel will be used to compare SST observations in the infrared region with the SMMR temperature measurements . The capabilities of the VIR are well estab- lished. 1.3. Orbit and Mission Characteristics The general orbital characteristics of SEASAT-A are defined in table 1-2. These general parameters are not likely to change, but there remains considerable flexibility to establish the detail characteristics of the orbit. The SEASAT-A ground trajectory is shown in figure 1-18, and this basic orbit will remain unchanged. The orbit is ± 72° latitude, but with the swathwidths of the SASS, SMMR, and VIR, the coverage exceeds ± 75°. The altimeter covers ± 72°, but the SAR coverage is 75 °N and 69°S because of its right oriented position with respect to the trajectory. The global coverage build-up with time is shown in figure 1-19. Data will be collect- ed continuously by all instruments, except SAR. A 4 X 10^ bits/s recorder with a play- back rate of 640 x 10^ bits/s will permit global acquisition of all except SAR data. 180° 150° 120° 90° 80° 30° 0° 30° 60° 90° 120° 150° 180° 75" 4^^fi. i ^ ^ 1 OvA^^iflBSi V^- T -^C^^"-'^ )^ULA ^^^'^^^vyV^ T^ ^ 60° ^ iK^^^C^li^^^^v \/ 1 * ^^ '- •■: ''■■' Vp^/^v &^ /" 45° 30° A 1 \t /\ ^v\ /y^Ky^X^i^w^' """" / ^ ^%iJM yf / 15° 0° - V^Vw^^ V^ ^ ^V2V^¥ ■15° - . . \ \ \t\,^^ V ■ ' y ' }"{/•* A ' ^i.^T"'^ •30° ._. \ \ \l l\f \ \ \jf / / /■ Tvlx-^^L V ^ 45° •60° J' SIX STATION COVER ALASKA (ULAI GOLOSTONE (GDSI ROSMAN (flOSI MADRID (MAD) ORRORAL (ORRI ST. JOHN CANAC AGE \ l^ \ \ ^ NASA V^ \ \ \ IAN \^ \^ N. N. 'v////i 1 ^\N^ J^>^^^^^'^^^^^yz^ ' ~~ ^^^ 180° 210° 240° 270° 300° 330° 0° 30° 60° 90° 120° 150° Figure 1-18. --SEASAT-A trajectory and ground station coverage. 1-14 180° 75° 60° 45° 30° 15° 0° -15° -30° -45° -60° 100 min 12hn 36hr< Figure 1-19. --SEASAT-A global coverage. However, it is important to distinguish between data to be acquired in near-real- time and data to be lised for non-real-time applications. Only the readout station (ULA) at Fairbanks, Alaska, will acquire data for near- real-time use (up to 6 hours after initial acquisition by the sensor) . Although the details of the SEASAT-A orbit are not precisely determined, the basic requirement is to have global coverage at 18.5 km (10 nm) increments at the equator in 152 days. This is the Earth's geoid measurement requirement. The pass-to-pass separation at the equator will be about 2800 km, the exact value depending on the altitude. Figure 1-20 shows one possible configura- tion of the trajectory build-up. Both ascending and descending legs of the trajec- tory are shown. The 0th orbit on day one is shown at the right-hand segment of the curve for the ascending mode. The next orbit (No. 1) is displaced 2793.6 km to west. Observe, however, that orbits No. 21 and 43 pass within 18.5 km and 37.0 km, respective- ly, of orbit 0. Thus, in just over 32 days, three passes occur within 37 km; or in 4.47 days, four passes (orbit No. 64) occur with 54.5 km. IVhile these slight displacements do not affect the coverage of the SASS, SMMR and VIR, they do satisfy the altimeter re- quirement and permit consecutive daily coverage for three or four days by the SAR system (with no subsequent coverage for about 70 days for this particular orbit) . This is an important consideration in the selection and design of experiments which will utilize SAR data. A limitation is placed on the SAR data acquisition because of its high data rate of about 100 X 10^ bits/s and the orbital parameters. Data from SAR will not be recorded on-board, but will be directly read out at Alaska, Goldstone, Rosman, and St. John. (See figure 1-18.) All the coastline of the United States will be covered, with the exception being Hawaii. Such a limita- tion may be partially corrected should NASA be in a position to include one or two semi- transportable stations to augment existing ground-receive stations for the LANDSAT series of satellites. Other SAR data capa- bilities and constraints are delineated in section 1.4.1. 1-4. Data Flow and Interfaces The prime elements of the SEASAT-A end-to- end data system are sketched as a flow dia- gram in figure 1-21. The prime elements have been designated to key laboratories, facilities, and centers of capability with- 1-15 00 o p o SI oo O 1— 1 o a> SI z « • H^ o E 2 .^ ^^ o lf\ sO •— 1 (/) CO CVJ I^ g" m LU •— 1 II vO o E N o 1^ II lO. • CM •>- s 1^ E E .^ ^ . .^ ^ — . oo gf^ m ^ II ii T (/I O to to O Of o Of Q 1 L T¥HF'Ss s ^ CVJ ^ l-H OO CO — s — 4— <^ o- ^^ ^ oo C E E .^ -^ CVJ NO I— • . o . CO m a^ csj CM '^ i/> O* o C3 to o o to < -3 '^1 a|_ **^ r^ o ^ '*^ — *" s s t/\ 1^ "as 2 ^ -. "if- 5^ iTn (\i J5S ^ Sea _ 5S; 23- 3^ S O V (A § •H 4J u u 4-> o < < o tN (U 3 1-16 SCHEDULE AIDS SATELLITE SUBSYSTEM CMD TLM TRACKING TRACKING AND DATA ACQUISITION SUBSYSTEM CMD TLM TRACKING MISSION OPERATIONS AND CONTROL SUBSYSTEM MISSION PROFILf SAR DATA MISSION PLANNING SUBSYSTEM SAR DATA PROCESSING SUBSYSTEM LOW-RATE DATA ORBIT/ ATTITUDE SUPP DATA PROJECT DATA PROCESSING SUBSYSTEM r ALGORITHMS NEAR-REALTIME LOW-RATE T/M (LIMITED COVERAGE. ULA) OPERATIONAL DATA PROCESSING SUBSYSTEM SEQUENCE REQUESTS EDR EXPERIMENT TEAM SUBSYSTEM EDR's ALGORITHMS EXPT TEAM USERS PDR PDR USER DATA DISTRIBUTION SUBSYSTEM PROCESSED DATA USERS RAW DATA I ' 1 (SOURCE =TBD) INDEPENDENT" -H RAW DATA |— .PROCESSORS I MNDEPENDENT^ "H RAW DATA I . USERS I Figure 1-21 . --Elemer ts of the SEASAT-A end-to-end data system. in the Federal government. Specific respon- sibilities are summarized in table 1-3. The general features of data flow important to the NOAA interface are the following. First, the basic mission plan for data acquisition is established about five weeks in advance. This primarily affects the SAR data and is discussed in paragraph 1.4.1. It is anticipated that the mission plan can be altered up to one week before actual overflight. Second, the near-real-time data (0 to 6 hours) will be transmitted directly via satellite relay from Fairbanks, Alaska, to Monterey, California for processing at FNWC. Third, the non-real-time data will be assembled daily at GSFC's Mission Operations and Control element and transmitted to JPL . The downlink for all non-real-time, low- data rate acquisition is the unified S-band at 2287.5 MHz. Such data will be received at Alaska, Goldstone, Rosman, Madrid, and Orroral (fig. 1-18) and played back to GSFC via the STDN network giving complete global coverage (-± 75° latitude) for the low-data rate sensors. Further, the raw data will be archived at GSFC. Table I- 3. --Data flow element responsibilities Subsystem element Organization Mission planning JPL Satellite JPL/LSMC Tracking d, data acquisition GSFC/STDN Mission operations § control GSFC Project data processing JPL SAR data processing JPL Demonstration data processing FNWC Experiment teams Various User data distribution NOAA Fourth, the Project Data Processing com- ponent at JPL will be configured primarily to support the Altimeter, SASS, SMRR, and VIR Experiment Teams (paragraph 1.4.4.) and will process all data from these four sensors. Geophysically processed data, lo- cated in time and space, will be available 1-17 I UACMt V-T REAL TIffi (OPERATIOIIAL DBIONSTRATION) STOM NON-REAL TIME (RESEARCH) JPL Project Data Processing Subsystem 3 O- o e3 SAR Image Subsystem- < f KOAA & Ft;i!C Bulletin Ni;s/ f;MC !;cc/ Form /' iUbb K Otuvur —I rieETNUUERlCAL WEAThCS CCNikAL (UOMTCBEYI -t.1 -^±±11 *Om*IIONM_QfwONS1IAnON* I Up to 7 Hours After Acquisition About Two Weeks After Acquisition Detail of NOAA data flow Figure 1-22 . --SEASAT-A instrument data flow. from the altimeter, SASS, and SMRR. The VIR data will be processed for enhanced imagery of ocean surface features only. Lastly, all data processed at JPL and converted to geophysical information will be forwarded to NOAA, where it is to be archived and made available to the marine community. The data flow, data rates, and time delays in the SEASAT-A plan are sum- marized in figure 1-22. The NOAA interface with the planned data flow system is dis- cussed in paragraphs 1.4.2 and 1.4.3. 1.4.1. Special SAR Data Acquisition Limi- tations. As observed earlier, the SAR sensor will be a high-data rate instrument and requires a Unified S-band downlink of about 20 MHz bandwidth using analog modula- tion centered at 2265.5 MHz. The recording requirement is for a minimum of 100 x 10^ bits/s and, hence, only surface recording is feasible at present. As noted earlier, all major U.S. coastlines will be viewed by the SAR acquisition system. There is another major consideration in planning SAR experiments and activity. It is planned to collect data from only 400 orbits of SEASAT-A.* This is slightly over one per day. From these 400 passes, film images from 260 would be image processed by mosaic techniques into scenes of 100 km width by up to 4000 km in length with 25 m spatial resolution. Only 26 selected passes will be digitized and available on computer com- patible tapes (CCT's). One ten-minute pass will generate 18 image CCT's at 1600 bpi. All SAR data processed at JPL is to be geo- metrically corrected with absolute location to 200 m and relative location to 25 m. *This is the U.S. data acquisition capa- bility. The Canadians are now considering modification to their LANDSAT receiving system and development of a SAR processor which would significantly increase the SAR acquisition capability. 1-18 The limitations and capabilities of the SAR sensor will require judicious planning by NOAA and other users well beyond the five week mission planning leadtime. It also poses the problem of how best to plan perishable environmental systems which are relatively short-lived compared with the five-week lead time for mission planning for the SAR. For example, the relatively long wavelength of the SAR L-band is most likely to penetrate hurricane conditions and gain a synoptic view of such severe wind-wave conditions. In this instance, a lead time measured in days and hours would be needed. 1.4.2. Non-Real Time Interface. The inter- face for non-real time data between the SEASAT-A Project and NOAA will be through the EDS/NCC/Satellite -Data Services Branch. All data will be in geophysical units and available ten to twelve days after acquisi- tion. These data will be archived and dup- licated for those users requesting these data on a reimbursable basis. Except for selected data requested by members of the SEASAT-A Project Sensor Teams or for special DoD requirements, all geophysically proc- essed data will be available on a reimburs- able basis to the public and private inter- ests through EDS. The data format will be imagery for the SAR and VIR sensors and CCT's for the re- maining sensors and some SAR data. Reim- bursement costs have not been set, but will be established along the same guidelines as now used for LANDSAT and NOAA satellites. 1.4.3. Real-Time Interface The prime recipient of real-time data will be the National Meteorological Center (NMC) of NWS. The interface will be established directly between FNWC and NMC. NASA will be responsible for any additional data links between these two facilities. The algo- rithms developed that convert engineering lonits to geophysical units at FNWC are the joint responsibility of the Navy, NASA, and NOAA. FNWC will provide quick turn- around (about one hour) of data to geophysi- cal units and make it available to NMC for either model ingest or field analyses. The prime environmental features to be processed for near-real-time demonstration are surface winds, temperature, and wave height. All near-real-time data users will receive data from NMC. Special products may be generated outside NMC but made available to users through NWC facilities. For example, near-real-time sea surface temperature maps may be provided by the Environmental Prod- ucts Group (EPG) of NESS to supplement on- going NESS specialized products. This example is also useful to illustrate the complex interactions of the SEASAT-A sensors to derive a single product. Figure 1-23 is a flow diagram for the processing, cor- rection, and analysis to derive a single product from SEASAT-A. The algorithms at FNWC must be capable of processing the variable corrections if the analyses are to be accomplished in near-real-time. Other- wise, SST products will be derived on a non- real-time basis with availability about 15 days after acquisition rather than 2 to 3 days. 1.4.4. Experiment Teams. Each of the five sensors on SEASAT-A will have a NASA/JPL experiment team responsible for instrument verification, validation, and continuing performance evaluation. The experiment teams will be highly interactive with the mission planning element shown in figure 1-21. A number of NOAA experimenters are on these teams as noted in figure 1-24. As now structured, it is only through the experiment teams that requirements for special data acquisition can be accomplished. The team members will typically have the instrument data within ten days; and at the same time, it is transferred to EDS/NCC/SDSB. Instrumentation Variable Product Foam SMMR Water Vapor Sea Surface Temperature Liquid Water Wind SASS Altimeter Waves VIR Cloud Check 1 R Sior^^""* ^ 1 Figure 1-23. --Near-real-time temperature analysis. sea surface 1-19 SCAT EXPI TEAM SMMR tXPI TIAM INDEP RAW DATA USfRS ORBITAL SEQUENCE PROFILE tRACKlNC SUBfACt SU> SMMB CHOVITZ TOWNS END UcCOOGAN HALBta^ JONES MOOBE BLAC« flt»C£B!> BuFENACn SHERMAN MAvES BENEDICT KEUUEDEB CBOSCUP LOWBV BENEDICT OPEBATIONS OPEBATIONS OPS RAM IPl -ISSIUh ■lANMNC Figure 1-24. --Experiment team interface data flow. 1-20 APPENDIX II. GLOSSARY OF TERMS AIDJEX Arctic Ice Dynamics Joint Experiment AOML Atlantic Oceanographic and Meteorological Laboratory APL Applied Physics Laboratojpy (Johns Hopkins University) APOLLO NASA (Moon) Spacecraft Series APT Automatic Picture Transmission ARIES Astronomical Radio Interferometric Earth Surveying System AVHRR Advanced Very High Resolution Radiometer BLM Bureau of Land Management CEDDA Center for Experiment Design and Data Analysis CCT Computer Compatible Tapes COFI California Coastal Fisheries Investigation COTR Contractor Officer's Technical Representative CUNY City University of New York CZCS Coastal Zone Color Scanner DCPLS Data Collection and Platform Location System DCS Data Collection System DMSP Defense Meteorological Satellite Program DOD Department of Defense ECON ECON, Incorporated (NASA Benefits Contractor) EDS Environmental Data Service EODAP Earth and Ocean Dynamics Applica- tion Program EPA Environmental Protection Agency EPG Environmental Products Group ERDA Energy Resources Development Administration ERL Environmental Research Laboratories ESG Environmental Sciences Group ESNR Electrically Scanned Microwave Radiometer FGGE First GARP Global Experiment FNWC Fleet Numerical Weather Central GARP Global Atmospheric Research Program GATE GARP Atlantic Tropical Experiment GEMINI NASA Earth Orbiting Manned Spacecraft (pre-Apollo) GEOS Geodynamic Experimental Ocean Satellite GISS Goddard Institute of Space Science GOES Geostationary Operational Environ- mental Satellite GRDL Geodetic Research and Development Laboratory GSFC Goddard Space Flight Center HRPT High Resolution Picture Trans- mission IDOE International Decade of Ocean Exploration IGOSS Integrated Global Ocean Station System IOC International Oceanographic Committee IR Infrared ISOS International Southern Ocean Studies ITOS Improved TIROS Operational Satellite JASIN Joint Air/Sea Interaction Project JPL Joint Propulsion Laboratory LAGEOS Laser Geodynamic Satellite LAT'IDSAT Earth Resources Technology Satellite (Formerly ERTS) LRC Langley Research Center (NASA) MARAD Maritime Administration MAREP Marine Environmental Prediction MARMAP Marine Resources Monitoring, Assessment, and Prediction MBO Management by Objectives MESA Marine Ecosystems Analysis MLC Major Line Component MONEX Monsoon Experiment MSS Multi-Spectral Scanner NASA National Aeronautics and Space Administration II-l NAVAIR Naval Air Systems Command NCAR National Center for Atmospheric Research NCC National Climatic Center NCP National Climate Program NESS National Environmental Satellite Service NGS National Geological Survey NIMBUS-G NASA experimental research satellite NMC National Meteorological Center NMFS National Marine Fisheries Service NOAA National Oceanic and Atmospheric Administration NODC National Oceanographic Data Center NOIC National Oceanographic Instrumen- tation Center NORPAX North Pacific Experiment NOS National Ocean Survey NWS National Weather Service OCSEAP Outer Continental Shelf Energy Assessment Program ODAS Ocean Dynamics Advisory Subcom- mittee PDP Program Development Plan PEG Pacific Environmental Group PI Principal Investigator PMEL Pacific Marine Environmental Laboratory PMT Program Management Team POE Primary Organizational Element POLEX Polar Experiment POLYMODE Polygon Mid-Ocean Dynamic Ex- periment RDT Research and Demonstration Team RMS Root Mean Square S-193 NASA SKYLAB's Combination Micro- wave Radiometer/Radar Scatter- ometer /Altimeter SAIL Sea/Air Interaction Laboratory SAR Synthetic Aperture Radar SASS SEASAT-A Scatterometer System SEASAT-A Name of NASA's Ocean Dynamics Satellite SDSB Satellite Data Services Branch SEFC Southeast Fisheries Center SKYLAB Name of NASA's Manned Spacecraft Sky Laboratory (1972-73) SLAR Side Looking Array Radar SLOPE Sea Level Observation and Prediction Program SMMR Scanning Multichannel Microwave Radiometer SPOC Spacecraft Oceanography Group (NOAA/NESS) STDN Spaceflight Tracking and Data Network SWFC Southwest Fisheries Center TIROS-N Television Infrared Observational Satellite (Improved - 1978) ULA Fairbanks, Alaska, readout station VHRR Very High Resolution Radiometer VIR Visible and Infrared Radiometer VISSR Visible Infrared Spin Scan Radiometer VLBI Very Long Baseline Interferometer WMO World Meteorological Organization WISEX Winter Storm Experiments II-2 APPENDIX III. RESOURCE IMPACTS This Appendix discusses the resources required to conduct the experiments and analyses described in this PDP. These resources are not approved, but represent those requested for accomplishment of the planned activities in the prescribed time period. The SEASAT Program is a planned- for, single budget increase line item with major funding proposed as a FY 78 increase and remaining constant through FY 80. Beyond FY 80, re- quirements will be dependent on (a) the suc- cess of the various research and demonstra- tion programs, (b) the operational lifetime of SEASAT-A (design lifetime is one year but may extend well beyond that), (c) NASA plans for satellite programs beyond SEASAT-A, and (d) the potentials for an operational system in the future. The program will have an impact on both activity cost and block-funded asset require- ments. IIl.l. Activity Cost Each program element has an estimated activity cost for each of the program years. These estimates are subject to change through- out the program dependent on the priorities assigned to the various elements by the PMT. I II. 1.1. Research Elements Table 1 11-1 denotes the initial estimates of yearly activity costs for the research elements of the SEASAT Program. III. 1.2, Demonstration Elements Table III-2 denotes the initial estimates of yearly activity costs for the demonstra- tion elements of the SEASAT Program. III. 2. Block Funded Asset Requirements Block funded assets that will be required to carry out the SEASAT Program include aircraft, ships, buoys, and computers. Tables III-3 and III-4 list research and demonstration element requirements for block- funded assets. Computer requirements are based on the 360/195 system at an estimated $750 hourly charge. Aircraft costs for research elements are estimated at $1200/hr (C-130 or P-3 aircraft). Aircraft costs for demonstration elements are estimated at $500/hr (Buffalo or Aero Com- mander) . It is anticipated that the present comple- ment of moored buoys will be maintained and therefore no charges for moored buoys will accrue to the SEASAT Proj ect even though this data is vital to some program elements. Similarly, drifting buoys are either current- ly associated with on-going programs (AIDJEX) or will be purchased with program element funds and not as block funded assets. All block funded assets tabulated are in addition to other block funding on all current programs. I I I. 3. Projected Cost Summary Table III-5 summarizes the total activity costs including block funded assets, data archiving and distribution, and project administrative costs, of the recommended SEASAT-A Program. Data archiving and dis- tribution costs provide funds to establish and maintain an archive of geophysically processed data and provide these data to approved NOAA investigators as described in the PDP. (EDS will provide this service.) All other investigators, whether NOAA or non-NOAA, will obtain SEASAT-A data on a reimbursable basis. Project Activity costs cover a portion of Project Administration incurred by NESS. IIl-l Table III-l . --Activity cost for research elements ($K) Element FY77 FY78 FY79 FY80 Total Coastal zone and lakes Shallow water waves/shoals Internal waves Circulation Storm surge and setup Nearshore winds Oil Lake and Bering Sea ice TOTAL 90 90 120 300 50 50 25 125 15 50 50 SO 165 50 50 50 150 15 50 50 20 50 165 20 15 30 50 95 30 305 340 345 1020 Open ocean Wave spectra, surface winds, and wind stress Surface temperature Steady and transient open ocean currents Atmospheric liquid-water and water vapor Tsunami Deep sea tides TOTAL 300 550 550 400 1800 80 130 130 150 490 80 250 250 250 830 50 50 25 125 t t t t t 235 100 35 370 460 1215 1080 860 3615 Geodesy Geoid determination Precise ephemeris TOTAL 75 40 115 130 225 355 140 200 340 185 160 345 530 625 1155 Polar studies Ice dynamics Ice mapping Ice statistics Hydrology Snow extent Snow depth Flood mapping Soil moisture (Climatology) TOTAL TOTAL GRAND TOTAL tOpportunity basis only *Undefined portion of hydrology total 40 50 75 50 215 20 50 50 50 170 25 25 80 130 60 125 150 180 515 10 20 20 25 75 10 675 20 2020 20 1930 25 1755 75 6380 III-2 Table III-2. --Activity costs for demonstration elements ($K) Element FY77 FY78 FY79 FY80 Total Meteorology Data Acquisition and validation Model applications Boundary layer winds TOTAL 38 50 20 108 100 100 100 300 12 50 50 25 137 50 200 170 125 545 Oceanography Wave forecasting Sea ice chart improvement N.H. wave model applications TOTAL 15 25 40 25 105 30 25 55 30 30 50 110 15 55 100 100 270 Living Marine Resources Plankton distribution Bering Sea fisheries Surface layer transport TOTAL 10 75 75 75 235 10 100 100 75 285 45 100 100 75 320 65 275 275 225 840 Geodesy Geoid comparisons Operational systems study 25 50 25 10 110 TOTAL 25 50 20 25 70 10 550 110 640 TOTAL 20 70 550 640 GRAND TOTAL 155 600 640 1010 2405 III-3 Table I I I- 3. --Block-funded asset requirements for aircraft ($K) Element FY77 FY78 FY79 FY80 Total Research Coastal zones and lakes Wave spectra, surface winds and wind stress 80 70* 220 80 285 60 220 575 Demonstration Surface layer transport TOTAL 10 70 310 10 375 60 20 815 CLASS II/III SHIPS Research Open ocean currents Tides 90 50 115 60 30 235 110 Demonstration Plankton distribution Bering Sea fisheries Surface layer transport Geoid comparison TOTAL 130 40 150 460 100 50 325 30 130 100 90 150 815 *Additional 80 (96$K) hours would be required, but these will be flown in conjunction with other experiments. III-4 Table III-4. --Block-funded assets for computer requirements ($K) Element FY77 FY78 FY79 FY80 Total Research Coastal zone and lakes Open ocean currents Atmospheric liquid water and water vapor Geoid determination Precise ephemeris Lake and Bering Sea ice Tides 15 23 10 45 10 20 85 10 15 70 15 25 90 10 15 75 10 35 90 25 10 40 190 35 95 288 25 30 Demonstration Meteorological model applications Boundary layer winds Plankton distribution Bering Sea fisheries Surface layer transport Geoid comparisons Operational systems study Aircraft Ships Computers 8 8 22 12 12 24 8 23 24 4 50 46 24 8 12 70 32 50 TOTAL 46 230 300 369 945 SUMMARY 70 310 375 60 815 460 325 30 815 46 230 300 369 945 TOTAL 116 1000 1000 459 2575 Table 1 1 1-5 . --Fiscal year summary of program development plan projected cost ($K) Element FY77 FY78 FY79 FY80 Total Research Coastal zone and lakes Open ocean Geodesy Polar studies Hydrology TOTAL 30 305 340 345 1020 460 1215 1080 860 3615 115 355 340 345 1155 60 125 150 180 515 10 20 20 25 75 675 2020 1930 1755 6380 Demonstration Meteorology Oceanography Living marine resources Geodesy Operational systems study TOTAL 50 200 170 125 545 15 55 100 100 270 65 275 275 225 840 25 50 25 10 110 20 70 550 640 155 600 640 1010 2405 Block funded resources Data archiving and distribution Project activity cost 116 1000 1000 459 2575 50 200 250 150 650 100 150 150 150 550 GRAND TOTAL 1096 3970 3970 3524 12,560 III-5 APPENDIX IV. TECHNICAL PLAN This appendix supports and provides more detail on the technical activity described in section 4 of this PDP. Except for the use of 'IV as the first digit, the numbering of paragraphs in this appendix is identical to the corresponding paragraphs in section 4. IV. 1. Overview of Planned Activity The summary and discussion of the planned activity in the text provides sufficient overview to the experimental effort. IV. 2. Activity Plan The NASA SEASAT-A system is principally a research platform to provide microwave sig- natures of the ocean surface most responsive to environmental factors that make the ocean surface a dynamic force- -waves , wind, tem- perature, current, and level. Much of the NOAA plan is oriented toward research with SEASAT-A, but with the potential benefits to NOAA estimated to be quite large (section 3) . An important part of NOAA's plan during the second half of the SEASAT-A lifetime (planned for one year with expendables for three years) is in operational demonstration. The demonstration will be performed only after verification and calibration of the SEASAT-A sensors as a part of the research activity. IV. 2. 1. Research Considerable aircraft and satellite research has been used to develop the NOAA experimen- tation program. Certain experiments will involve significant field experimentation and others will be conducted on an opportun- ity bases. The research program will have a prime interest in the basic comparison of engineering and geophysical data produced from SEASAT-A as compared with in-situ data sources. In contrast, the operational demon- stration will have a major interest in the information produced from the SEASAT-A data. IV. 2. 1.1. Coastal Zone and Lakes. The increased pressure on the U.S. coastal region by competing resource requirements and the capabilities of SEASAT-A have guided the development of this activity. In cer- tain instances, there is redundancy between the coastal effort and that proposed for the open ocean effort which follows. This has been a necessary step dictated by the high- gradient features found in coastal regions as compared to the open ocean and the spa- tial resolutions of the SEASAT-S sensors to resolve these gradients in space and time in a useful manner. Certain experiments will take advantage of other satellite systems to supplement the SEASAT-A data or provide unique data sets. Such data will be most valuable in develop- ing the requirements for environmental satellite systems in the mid-80's. IV. 2. 1.1.1. Shallow water waves/shoals. The objective of the shallow water wave research effort will be to test refraction models by means of SAR imagery and to tune and vali- date hindcast models against observations of average wave height by the altimeter. Wave refraction, as directly measured in the SAR imagery, will be used to estimate water depth in shoal areas. Coastal wave climatology does not exist for most areas contiguous to the Continental U.S., Alaska, and Hawaii. Therefore, no modern data base exists upon which to base the technological requirements of the 1980 's in an efficient and cost effective way. This is true mainly because existing wave measurement programs have not been conducted at the required density level and have not been combined with validated shallow water hindcast models. Thus, oil, chemical, and nuclear pollution dispersion models are handicapped through insufficient knowledge of the effects of wave action and climatol- ogy on the general circulation. For exam- ple, the design of offshore rigs to with- stand high waves suffers from models which predict the 100-year highest wave in the Gulf of Alaska to be anywhere from 12.S feet to 175 feet. The SEASAT satellite can aid in the establishment of a proper data base by means of the altimeter and SAR images. In addition, the wind measuring sensors can aid in the hindcasting needed to supplement the measurements. The SAR defines a footprint by measure- ment of the transit time and the doppler frequency shift of the return energy. Since the reflecting waves are themselves in motion, an additional doppler shift is in- troduced which causes a "mis location" of the footprint. For images of swell, this problem does not appear to be significant. Thus, SAR should provide a useful data base for wave refraction studies. An entire wave climatology cannot be developed during the lifetime of SEASAT-A. Verification of existing refraction models can be accomplished to yield high confidence IV-1 or to correct the models. In contrast, the detection of shoals requires a swell system wavelength that is at least a factor of ten or less than the depth in the shoal region. Thus, one-time coverage with SAR can be very useful for depth measurement. The need to update navigational charts to eliminate doubtful hydrographic data has been a major concern of the International Oceanographic Committee (IOC) since 1965. An indication of the magnitude of this prob- lem is contained in Publication No. SP-20 of the International Hydrographic Bureau, which indicates that large numbers of shoals are inaccurately charted either in position or depth. Thousands of soundings show depths that are too deep because of curving acousti- cal paths between the ship platform and ocean bottom and too shallow where echo soundings occur from intermediate scattering layers or are improperly scaled or calibrated by the boat operators. Several approaches to remote sensing of water depth have been studied. Color/ density, thermal change, wave refraction, and direct laser ranging are examples. Air- craft and satellite experiments indicate that thermal changes depend on too many non- depth related variables. Laser ranging, while feasible from aircraft, appears impractical from satellites. The color/density approach has been demonstrated using variable filters, films, and photographic enhancement. Com- puter processing of multispectral electronic scanner data has shown that depths of 20 to 30 m in nonturbid water can be determined. Investigations have shown that wave length changes and wave refraction angles are detectable in optical transform systems to generate directional and frequency charac- teristics of imaged waves. The deep water transform compared with shallow water trans- form is an indication of the change in bottom depth. LANDSAT imagery has been processed so that nearshore depths could be estimated. SEASAT-A will afford an opportunity to use radar imagery for processing of wave refraction for depth determination. The wave refraction technique for depth determination may involve the measurement of a particular wave length appearing in a single image, or may require repeated coverage. In order to demonstrate the utility of SAR to improve charting of shoal positions and hazards to navigation in cloud covered areas, a wave refraction experiment for depth determination is proposed. The experiment will be carried out in two parts: (1) SAR imagery taken over the Bahamas test site will be processed and related to known reliable hydrographic charts. (2) Applying the Bahamas cali poorly charted s Islands will be on-site surface/ tion as a viable optical processi of wave lengths latter activity availability of the Pacific--pos the technique developed at bration site, SAR imagery of hoals in the Pacific Trust processed and compared with subsurface data for evalua- technique to chart depth by ng of sequential SAR imagery and wave refraction. This is highly dependent on the a SAR readout station in sibly Hawaii . IV. 2. 1.1. 2. Internal waves. The objectives of this investigation are to detect and ascertain the direction of the principal group velocity vector of internal waves and wave packets in any weather, day or night, in the deep ocean and the continental shelf areas. Additionally, an estimate would be obtained for a seasonal geographic distri- bution of the wave occurrences, with esti- mates of energy content and dissipation produced. The dissipation of energy in the continen- tal shelf region by transmission of energy from the barocline internal tide into internal waves and then subsequent breaking is currently an unknown quantity in the total earth-moon-tidal dissipation calcula- tion and could account for up to 10% of the dissipation on a world-wide basis. In addition, the transference of this dissipated energy into a bottom boundary layer shear flow is a possible mechanism for resuspension of sediment on the shelf. Experiments to determine these resuspension areas are currently being carried out by the MESA program. SEASAT SAR data should pro- vide a better estimate of the internal wave field than has been previously available. Previous investigations have been done using LANDSAT I and II data; however, this data is limited to clear weather and daytime observations. Analysis of selected SAR data will be performed over the deep ocean and continen- tal shelf areas. Comparisons will be per- formed with previous work using the LANDSAT I and II analysis. Intercomparison will be made with aircraft SAR data and conventional aerial photography. Additional ship of opportunity measurements made during other studies (see Coastal circulation, IV. 2. 1.1.5 and Surface layer transport, IV. 2. 2.3.3) will be correlated, and a final assessment of the utilization of SEASAT data for this type of study will be made. IV. 2. 1.1. 3. Storm surge and setup. The principal objectives of this study are to measure the setup of the ocean surface along coasts and in embayments in response to the onshore movement of large storms . IV- 2 Measurements of the surge response and onshore slope due to barometric loading and wind stress are necessary to validate the current modeling efforts for storm surge. Existing validation efforts are confined to protected onshore tide gauges and occasional offshore deep tide gauges. Initial work in this area has been per- formed using GEOS-3 data. However, the limited accuracy of about one meter and the extremely limited data set produced in the GEOS-3 operational mode have caused potential opportunities of collecting data on storms moving onshore during satellite overpass to be lost. The total SEASAT operational mode coverage should provide a much better data set to be assembled. To maximize the potential of this study, a weather watch of all large storms on the East, West, and Gulf coasts of the U.S. will be conducted with storm tracks and predicted movements plotted. SEASAT data will then be compared in areas where the altimeter, scat- terometer, and SAR data are coincident or in close proximity to the storm tracks. These measurements will form the inputs to the storm surge models and be used in hind- cast comparison. IV. 2. 1.1. 4. Nearshore winds. The nearshore forecast wind and climatology are now based mainly on coastal measurements and ship reports. Ship reports are infrequent and coastal measurements are often biased by the effect of land features near the local measurement site. The large footprint and the relatively infrequent satellite observa- tion preclude use of the SEASAT wind meas- uring sensors for monitoring a particular coastal location. The measurement of oceanic wind fields, however, Should be greatly improved so that coastal wind data can be improved by simple extrapolation or by cal- culation based upon an improved pressure field. Intracoastal traffic is largely composed of relatively small vessels that are highly susceptible to the effect of local mesoscale weathersystems. SEASAT can address this problem only indirectly by improved synoptic scale forecasts using oceanic scale wind field data. It is therefore feasible for the nearshore wind field to be developed based upon an iterative procedure utilizing the FNWC oceanic wind analyses which incorporate SEASAT measured winds. The wind field could be specified on a grid scale compatible with proposed shallow water wave models so as to provide optimum synergism. The case studies selected by the wave group would be appropriate for the purpose of wind analysis. Surface winds determined by low flying aircraft and surface vessels will be utilized to verify the procedure developed. I V . 2 . 1 . 1 . 5 . Continenta I She If /nearshore circulation -processes. Measurements from the SEASAT-A/NIMBUS-G satellites permit extrapolation of nearshore circulation processes by inferring distribution of nearshore surface winds. The nearshore wind field, and hence the near surface wind induced circulation, can be delineated with the use of the SASS and SMMR sensors. However, the spatial resolution of both these instruments (about 50 km) is marginal for measurement of nearshore winds. (About 25 km is desired.) The approach will be to combine the existing nearshore wind station measurements with the open ocean SEASAT-A wind data to generate a consistent local field in the coastal region. Data from buoys, TIROS-N, and GOES will support the windfield determination. The required wind analysis has been discussed in the previous paragraph (IV. 2 . 1 . 1 .4) . With conventional techniques, winds that are persistent will be used to determine basic circulation features. Using the TIROS-N and/or Nimbus-G thermal detectors, checks on the results will be made by moni- toring the thermal manifestations (sea sur- face temperature) of basic circulation features . This circulation study is highly dependent upon the results of the nearshore wind ex- periment (paragraph IV. 2. 1 . 1.4) . In turn, two demonstration experiments are highly de- pendent on the circulation study. Figure IV-1 illustrates the overall planned activi- ty. The two demonstration experiments, important to fisheries, are discussed in paragraphs IV. 2. 2. 3.1, Effects of wind induced turbulence on plankton, and IV. 2.2. 3. 3, Surface layer transport. IV. 2. 1.1.6. Oil. It is proposed, for those areas and times where oil spills occur, to examine the SAR data as an aid to oil spill detection. The detection of an oil spill and the determination of its trajectory are required by NOAA and other government agen- cies (EDS Deepwater Ports, ERL/OCSEAP, and the U.S. Coast Guard) to predict the environ- mental impact of oil spills and to assist in cleanup activities. The detection of surface pollution is possible with SAR for the more typical spills and potentially by SASS and SMRR for a very large spill. The continued monitoring of large spills by the latter two instruments will allow gross trajectory analysis. Other SEASAT data such as wind field, currents, wave field, etc., could be used as inputs to trajectory models. IV-; Oceanic Winds Effects of Wind on Plankton Distribution Continental Shelf and Nearshore Circulation Shoreline Wind Stations Coastal Wind Field and Analysis Surface Layer Transport Clear-Sky Checks on Circulation from TIROS-N, NIMBUS-G and LANDSAT Buoy, Ship, Satellite Coastal Winds 1 Figure IV- 1. --Relationship between wind and circulation-related experiments. Specific areas of research include: (1) the suitability of SEASAT-derived wind fields and wave fields as inputs to existing trajectory models and (2) the determination of the signature of oil by the SAR and other SEASAT sensor systems. Moreover, all oil spill experiments should be coordinated with the SEASAT-A orbit schedule to maximize the environmental data collected. IV. 2. 1.1. 7. Coastal and lake ice. The chief objective of this experiment is to demonstrate the effectiveness of all-weather/ day-night SAR for determining ice location, distribution, and type in the Great Lakes under various meteorological conditions and observation of shore-fast ice buildup and breakup along the Alaska coast. Second- ary objectives include demonstrating the value of the multisensor approach to ice studies in the selected areas and investi- gating the relation between signal attenua- tion as a function of cloud type and thick- ness as well as precipitation type and intensity. Ice distribution, location, and type are the items principal to transportation inter- ests in the Great Lakes and the Alaska North Slope. The all-weather/ day-night capability of this sensor is expected to demonstrate its superiority over other types of weather- dependent sensors. Aircraft SLAR flights have confirmed the usefulness of L-band frequencies for lake ice studies. The nar- row swathwidth (100 km) is more than compen- sated for by the fine resolution (25 m) . The primary experiments will be correlated with aircraft flights currently operated by NASA and the Coast Guard over the Great Lakes and a joint USGS /NASA/NO AA effort in the Beaufort Sea. Lake Erie is the most prodigious ice producing Great Lake and will be the focus of major efforts for air- craft and surface truth observations . The SMMR data may be marginally useful for large scale lake ice mapping and determing the attenuation effects of rain and snow at various SMMR frequencies. The SMMR will be used only in a correlative manner in this experiment. Studies relating to the freeze- up and breakup of Great Lakes and shore fast ice will benefit from the synoptic broad- scale data available during the very common cloudy periods. IV. 2. 1.2. Open Ocean. Experiments in the coastal zone and lakes will typically be local (up to hundreds of kilometers) in contrast to the open ocean (up to thousands of kilometers) and global research activi- ties. A major portion of the research is devoted to sea-air interactions. This emphasis is necessary because this research supports the Meteorological Demonstration effort (paragraph VI. 2. 2.1). A major portion of the benefits from a SEASAT-type operational system depend on the demonstra- tion element. IV. 2. 1.2.1. Wave spectra. The need for near real time wave forecasts cannot be overstated. For example, the transportation and installation of oil drilling rigs is critically dependent upon accurate wave fore- casts. The cost of delays in installation IV-4 of a drilling rig is measured in tens of thousands of dollars per hour. In addition, the maximum design wave height for a drilling rig is estimated to be two million dollars per foot. Therefore proper wave climatology as well as forecasts must be available to the industry. On a somewhat larger scale, as the cost and availability of fossil fuels become critical, the use of optimum ship routing programs becomes essential to the maintenance of the competitive position of U.S. shipping interests, both civilian and military. Knowledge of wave climatology and the ability to forecast wave spectra on a global scale are necessary for such programs. Wave climatology for a given area can best be determined by a proper hindcast model which has been tuned by measurements. For example, a hurricane wave model has been developed based upon data measured in the eyewall of hurricane CAMILLE, the most severe and destructive storm (in terms of dollars) to strike the Gulf Coast. The maximum significant wave height measured was 47 feet. Hindcasts of the 29 September, 1915 storm which struck New Orleans indicate significant wave heights were 55 feet as the storm moved over the offshore area south of the Mississippi delta. A measurement pro- gram, therefore, is not likely to measure the 100 year event. It will allow accurate prediction of the event, however, when com- bined with a proper model. While the accuracy of present spectral models is felt to be limited mainly by inaccuracies in the specification of the wind field, improvement is still needed in the treatment of swell propagation and the specification of the atmospheric input and the dissipation components of the spectral energy source function. Thus, determination of the impact of satellite data on wave forecasting may be limited by the adequacy of the physics of present models. Improved spectral wave forecasting models will be in operation by 1978. Extension of these models to a truly global scale is dependent primarily upon establishment of surface wind measurement techniques from satellites. The satellite systems do not measure wind directly but rather the surface roughness, which may be more directly related to surface stress than to windspeed. In any event, development of the satellite techniques is already underway. The research aspects of this plan will be accomplished by an approach which includes the following elements: (1) verifying fore- casts in densely traveled areas such as the Gulf of Alaska and the North Atlantic shipping lanes; (2) extending the validity of forecasting and physical models to regions of high winds that are both circular and have very long f6tch and duration such as in hurricanes and in the Southern Ocean; and (3) further refining the relationship between wind, surface stress, and surface roughness on a scale measurable by satel- lites. IV. 2. 1.2. 2. Surface winds. Next to the heating effect of the Sun, surface winds are the dominant force in the dynamics of the ocean. Through momentum transport, the wind provides the energy source of the major ocean current systems and forms the wave climatology. Thus, the global distribution of sea surface temperature is a manifesta- tion of wind forcing. The key to improved marine environmental prediction is there- fore dependent upon improved prediction of surface wind fields. Present models are mainly dependent upon a knowledge of the atmospheric pressure to establish, through models, a surface wind field. The pressure measurements are obtained from ship reports. Vast areas of the southern hemisphere oceans, however, have little ship traffic. Figure 1-18 (Appendix I) depicts the sub- satellite track of SEASAT for one day. It can be seen that global surface wind analy- sis and predictions can be extended to the majority of the world's oceans. The rough- ness parameter sensed by the satellite, however, is not windspeed per se, but a manifestation of momentum transfer or stress to the ocean. It is therefore a necessary objective to both improve and validate the physics of existing algorithms and develop numerical models capable of global scale analysis and predictions. Prior to laimch of the satellite, modeling efforts should be initiated. These models will use existing algorithms which relate the satellite measurement directly to sea surface stress at normalized windspeed. At the same time, efforts should be made to improve the physics of the models to account for nonlinear effects and rainfall. The post launch phase will consist of verifica- tion of the measurements and demonstration of the effects of the SEASAT data base on the analysis and forecast products. Veri- fication should be accomplished along with legitimate experiments addressing other real problems such as the NORPAX, JASIN, ISOS, FGGE, and STORMFURY. The goal of the verification program will be to establish the accuracy and sensitivity of the satellite measurement of stress or normalized windspeed. The most cost effec- tive way to accomplish this would be to expand the scope of a planned experiment, e.g., JASIN, by means of aircraft and buoys to benefit from previously scheduled ship time. IV-5 IV. 2. 1.2. 3. Wind stress. Specification of the stress field over the ocean cannot be accomplished without ambiguity because of the motion and deformation of the surface. SEASAT, however, will measure a parameter of ocean roughness which is more closely related to stress than to the mean surface winds. Therefore, it is a reasonable ob- jective to attempt to specify estimates of the stress field on a global scale. If we are to understand and predict the wind-driven factor in the general circula- tion of the ocean, then we must understand how the oceans (acting as a huge brake on the atmosphere above) extract momentum from the atmosphere and redistribute this momen- tiom partly to the ocean wave field, partly to the ocean currents, and partly to dissi- pation. We have very little realistic knowledge of the relationship between the mean and the dynamic structure of the winds over the open ocean. This is true particu- larly at wind speeds greater than 15 m/s since the majority of observations were made under much lower wind conditions. Ironical- ly, an enormous (but unknown) fraction of the turbulent energy balance may be associ- ated with the stronger wind situations. The understanding of the nature of this balance along with an observation program on a global scale will be required to develop realistic models of the wind-driven contri- bution to ocean circulation and global estimates of the ocean wave field. The latter exerts considerable, but again, poorly understood control on the manner in which energy is extracted and partitioned from the atmospheric boundary layer over the sea. Aircraft and satellite measurements of microwave emissivity and radar scattering have traditionally been related to the surface wind due to the difficulty of measuring a more specific parameter such as surface stress, dissipation, rms slope, or Bragg wave amplitude. Surprisingly, this approach was proved to be useful during the SKYLAB experiment, suggesting SEASAT could be used to initiate operational forecast models. Proof that the forecast product has been usefully improved, however, will be difficult and greatly dependent upon establishment of the accuracy and precision of the physical parameter estimated by the satellite. One of the major advantages of the SEASAT program will be the capability to derive spatial estimates of the mean wind or stress field in the lower part of the atmospheric boundary layer. This strongly suggests that measurements of every detectable parameter of the atmospheric turbulence associated with energy in sheared wind fields over the open ocean should be made on a similar spatial scale to the satellite footprint, say a few tens of square kilometers. Most experiments conducted to measure the parameters of these turbulent exchanges of momentum and heat have been made from fixed platforms. Thus, a large and often con- flicting body of data exists suggesting that drag coefficients range from a constant value of order 10"^ to a dependency on wind velocity, atmospheric stability, and the open ocean wave background. Past results, therefore, cannot be reliably used to inter- pret SEASAT data. It is much more desirable to interpret satellite derived parameters of the wind over the open sea in terms of corresponding temporal and areal averages of the stress field. Ideal platforms for these are buoys and fixed platforms together with low flying aircraft equipped to observe, in situ, the stress field in the atmospheric boundary layer, along with sensors to profile the sea surface directly to account for the influ- ence of the waves. Thus a modern approach to ocean-wide estimates of wind stress may be given as follows: arrays of deep moored buoys which measure winds, waves, and air and sea temperature will provide fixed-point ground truth that will specifically be used, in this context, to calibrate and furnish a first-order time listing of the mean wind and the wave height conditions. Special aircraft flight patterns should then be flown to obtain spatial coverage of the wind, wave, and stress field for combination with the temporal measurements to evaluate the satellite measurement. Hence, SEASAT measurements can be extended to useful estimates of wind stress on a global scale which will begin to provide a realistic data base to obtain better esti- mates of global budgets of heat, mass, and energy. IV. 2. 1.2.4. Surface temperature. The pri- mary objective is to establish the relative and absolute accuracies of the SMMR-derived surface temperature. The 6.6 GHz channel of the SMMR will sense temperature over exten- sive areas of the ocean where, because of clouds, such measurements are difficult or impossible with satellite infrared radiome- ters. Although the relatively coarse spatial resolution of the SMMR observations (of the order of 100 km compared with 1-10 km for the IR) will probably preclude or lessen their value for many types of oceanographic applications, it is anticipated that the SMMR's nearly all-weather capabilities will enable some useful broad-scale (spatial and/ or temporal) uses of interest to oceanogra- IV-6 phers or meteorologists (e.g. in global circulation or climate models). The technical approach proposed is com- parison of the SMMR-derived radiant sea surface temperatures with operationally- derived satellite IR temperatures and ship data. The results will be stratified with respect to several classes of surface wind speed, liquid water content, and cloud cover data in order to define limiting con- ditions and to facilitate possible modifi- cations to the algorithms for surface tem- perature deviation. After the temperature accuracies have been established, and if they are found to be adequate for the purpose, then it is proposed to test the usefulness of these coarse-resolution temperatures in the study of broad-scale oceanic thermal phenomena or processes, particularly in areas of wide- spread or persistent cloudiness. Phenomena that are sufficiently conservative in time to permit time-compositing of the tempera- tures should improve the absolute accura- cies of the SMMR temperature. The results of this research will be useful to other SEASAT-A activities and to other major programs such as FGGE, NORPAX, and the planned National Climate Program. IV. 2. 1.2. 5. Steady and transient open-ocean currents. The primary objectives are to measure the position and surface velocity of the principal wind driven current systems in mid and high latitudes. These include the following current systems: (1) The principal western boundary currents together with the position, population, and generation of associated rings and meanders (Gulf Stream, Kuroshio, Brazil Current, and East Australian Currents) . Use this infor- mation gathered from the SEASAT altimeter data together with conventional hydrographic data and climatological hydrographic data to compute the total flow field initially to ± 10 cm/sec or approximately 10% accuracy and eventually to ± 1 cm/sec or approxi- mately 1-2% when better ephemeris data is available. (2) The Antarctic Circumpolar Current (ACC) and the position of the Antarctic and Sub- tropical Convergence Zones (ACZ) and (STCZ) , ■the flow through Drake Passage and the deflection of the ACC over submarine ridges in the Pacific; surface current systems of the Northern Indian Ocean in response to the seasonal monsoon--in particular the Somali Current and associated offshore gyres; also the transient currents in mid-ocean areas. Little is known about the time variability of the current fluctuations. If their frequency is low as are the MODE eddies measured west of Bermuda, SEASAT should be able to monitor them. Secondary objectives dependent on a more accurate orbit include measuring wind setup in the open ocean and against continental boundaries and possibly detecting the sur- face signature of standing Rossby waves in the ACC east of the Campbell Plateau. Many economic catastrophes such as the failures of the rice crop in Japan and the anchovy fisheries off Peru or of years of unusual numbers of icebergs in shipping lanes are attributed to fluctuations in ocean currents. It takes years of careful and expensive conventional observation to produce even a crude description of them. Measurement of the flow of steady and tran- sient open- ocean currents on a global synop- tic basis is currently impossible using in situ techniques. SEASAT is the only system available in the near future which will be capable of meas- uring the pressure and motion fields on a global synoptic basis. It will provide the long-term survey needed to reveal fluctua- tions in some ocean currents and possibly transient currents in mid ocean. Measure- ments of this type will allow calculation of transport of heat and nutrients to be made more accurately than is currently possible. The SEASAT observations, even though they deal entirely with the upper layers of the ocean, will be very valuable in contributing to a better data base on ocean surface temperature and upper level currents (para- graph IV. 2. 1.2. 4). The SMIC report of 1971 stated, "We would like to be able to recommend a monitoring program for the temperature distribution and currents of the upper ocean; however, we recognize that there is at present no econ- omical and effective way to perform such monitoring." (SMIC report 1971, p. 16).* The SEASAT program will mark a major step toward giving the observational data re- quired for advances in the ocean-atmosphere modeling; such models are essential for understanding climate dynamics and forecast- ing seasonal climatic anomalies. These are the objectives of GARP that rate among the most compelling in atmospheric sciences. IV. 2. 1.2.6. Atmospheric liquid water and water vapor. To convert SEASAT measurements into environmental parameters, it is neces- sary to apply corrections to account for the emissivity of the lower atmosphere which *SMIC report, 1971: Study of Man's Impact on Climate, published jointly by Cambridge University and The Massachusetts Institute of Technology. IV-7 is primarily related to the amount of water, both liquid and vapor, in the atmosphere. It is proposed to conduct a set of definitive experiments to more fully define the emissi- vity of the lower atmosphere through better parameters displaying the amount and distri- bution of water in the troposphere. This would lead to more accurate corrections to account for atmospheric emissivity and should enhance the ability of SEASAT to measure the amount and distribution of moisture in the atmosphere by residual tech- niques using data from the different sensor frequencies . The desired approach will be to measure the amount and distribution of moisture in the troposphere using upper air soundings and digital weather radar measurements from a single ship in the Tropical ocean. These shipboard measurements will be taken under selected atmospheric conditions at times coordinated with SEASAT overpasses. Models developed from GATE and other programs would then be used to refine the parameters for distribution of moisture in the troposphere and relate them directly to the SEASAT sensor outputs. The desired objectives will be to develop improved emissivity correc- tions and parametric techniques for esti- mating moisture concentrations in the tro- posphere based on the interrelations of all the various outputs of the SEASAT sensors. IV. 2. 1.2. 7. Tsunamis. If, during the lifetime of SEASAT-A, a major tsunami occurs, efforts will be made to search for this signal in the altimetry data. Because the tsunami takes approximately 10 hours to cross the ocean basin, a reasonable proba- bility exists that one of the seven or so orbits crossing the Pacific during that time will pass over the wave packet. Since the amplitude is small (usually less than 100 cm) , the wavelength rather long (50- 500 km) , and the coherent wave train con- tains only three or four oscillations, this effort will tax the capabilities of the instriiment and of the theory and computer programs used in the analysis of the precise ephemeris and geoid determination. The errors in the orbit determination will have a comparable amount of power in the same frequency range as the Tsunami signature but are likely to be more random. Likewise, it will be difficult to distinguish the tsunami from the uncertainty in the geoid height or deep ocean tides, except for its absence on other passes. For any such occurrences, a nonroutine analysis will have to be made. These orbits will be examined very carefully on an individual basis and several methods of signal extraction will be attempted. Another possible observation type would be an estimate of the statistical roughness of the sea surface on the scale of a tsunami wavelength both before and during the decay of the tsunami. The goal is to determine if tsunamis decay in deep ocean regions in the same fashion as determined by shoreline observations. In addition to the altimeter pulse shape, the SAR and other SEASAT-A instruments, which have a relatively large sampling area, could be utilized. IV. 2. 1.2. 8. Deep sea tides. This program focuses on the S^ea L^evel Observation and P^rediction Experiment (SLOPE) within the National Ocean Survey. The primary objec- tives are determination of the slope of mean sea level along the west coast of the United States, calculation of a sea level surface for use with SEASAT altimeter measurements of oceanic tides and sea surface topography, provision of critically needed sea-truth for altimeter measurements during the SEASAT mission, and determination of oceanic tides in the Eastern North Pacific from SEASAT altimeter data. The determination of oceanic tides and mean sea level plays a central role in both geodesy and oceanography. However, geodetic and oceanographic determinations of mean sea level in the north-south direction along continental boundaries disagree seriously. The discrepancy is about 30 cm in Europe and along the east coast of the United States, nearly one meter long the west coast of the United States, and several meters along the west coast of Australia. Since these dif- ferences are far larger than the uncertainty associated with either geodetic or oceano- graphic determinations, it is imperative for the National Ocean Survey to resolve this discrepancy. In particular, this discrepan- cy must be resolved before NOS's National Geodetic Survey undertakes the computation of a new National Vertical Control Network. In addition, a main purpose of SEASAT alti- meter measurements is to monitor oceanic tides and currents associated with sea surface slopes. Effective use of SEASAT altimeter data will be difficult in the presence of unresolved controversies up to one meter or more in the height of mean sea level . The projects described in this plan pro- pose to uncover the reason (s) for the anomalous determinations of mean sea level by estimation of the position of the mean sea surface using techniques that are little affected by errors in geodetic and oceano- graphic parameters. The SEASAT altimeter will be used to measure the sea surface height directly, and Very Long Baseline Interferometry (VLBI) will be employed to IV- establish the relative heights of tide gages on the U.S. West Coast (San Diego, Santa Monica, San Francisco, Crescent City, Neah Bay) . VLBI is a radio antenna system with synchronized atomic clocks and determines positions by measuring the delay in arrival time between measurement sites of extra- galactic radio signals. The slope of sea level will be determined by averaging altimeter data from SEASAT passes and by computing sea level at the VLBI linked tide gages. These independent calculations of sea level will be compared with each other and to the previous geodetic and oceano- graphic results. To allow this comparison in a common reference system, an accurate gravimetric geoid will be computed at the tide gages . The successful completion of this effort will require placement of an open coast tide gage along the Washington coast and deploy- ment of up to four deep sea tide gages off the west coast of the United States. The open coast tide measurements will be used to correlate coastal tides to tides at the long-term station at Neah Bay, Washington. Long-term open coast tide measurements will be available near San Diego and San Fran- cisco and at Santa Monica and Crescent City. The deep sea tide measurements will estab- lish the relation of the broad oceanic tides to the coastal tides. In addition, the deep sea tide measurements will serve as point control and sea-truth for determination of oceanic tides from the SEASAT altimeter data. IV. 2. 1.3. Geodesy. The Geodesy studies mainly involve the use of the altimeter data from SEASAT-A, and the effort is centered in the National Ocean Survey. The experi- ments will augment the research on improving geoid determination and sea level computa- tions underway with data from GEOS-3. IV. 2. 1.3.1. Geoid determination. The prime geodetic objective is to determine the geoid to the accuracy needed for use as a refer- ence surface for the sea surface topography (also called dynamic heights) . This should be commensurate with the expected precision of the SEASAT-A radar altimeter (within 10 cm). Other objectives, utilizing the altimeter data, are to obtain gravity anom- alies in ocean areas, to help determine sea slope along the U.S. Pacific and Atlantic coasts as a check on geodetic leveling, to compute deflections of the vertical near the shores of the U.S. as added information for the orientation of the new North Ameri- can Datum, and to improve the global geoid for a better gravitational field determina- tion. The unique advantage of satellite alti- metry is that it provides uniform global coverage (over the oceans) and, at the same time, furnishes essentially a ground meas- urement. Since the altimeter actually measures to the sea surface, no information is directly provided by a single measurement on the sea surface topography--the discrep- ancy between this surface and the geoid. As a first step, this difference can be neglec- ted and the geoid height obtained to an approximation of about a meter, which is the average magnitude of the sea surface topography. In a second phase, further refinements must be taken into consideration to utilize measurements, analyses, and sup- porting data to the 10 cm level to distin- guish the various components of the sea surface topography. The most important factor bearing on the required accuracy is the determination of the radial position of the satellite. This requires an extremely precise determination of the satellite orbit. Other factors which must be taken into account are bias in the altimeter measure- ment, the effect of the atmosphere on the radar pulse, and transient oceanographic and weather effects. The above factors all bear on refining the measurement of the altimeter to the sea surface. A coordinate undertak- ing for the second phase will be to deter- mine the geoid in selected areas to the 10 cm level of precision by shipboard gravi- meters for the purpose of calibrating the SEASAT altimeter measurements. Periodic phenomena in the sea surface topography may be accounted for by analyzing repetitive altimeter observations over the same areas. Another approach would be to obtain high- frequency gravitational data from other satellite experiments, for example, from a satellite-borne gravity gradiometer. Theo- retical approaches involving the principle of downward continuation from satellite height to the sea surface will be tried. The solution will be an amalgamation from various sources. By utilizing all possible information, the approaches mentioned above, and iterative techniques, progress will be made toward the determination of an adequate reference surface for the sea surface topography. IV. 2. 1.3. 2. Precise satellite ephemeris . To exploit the 10-cm precision capability of the SEASAT-A altimeter, the radial component of the satellite ephemeris should be known to a comparable accuracy. This requirement will extend the current state-of-the-art orbit determination process by at least an order of magnitude. To satisfy this re- quirement, software and operational capa- bility for the computation of the precise IV-9 ephemeris will be developed. This involves the determination of improved models for the perturbing forces on the satellite, coordination with other agencies for the placement of sufficient and adequate track- ing stations, and the determination of data reduction procedures. NOS/GRDL has already delivered large scale orbital data reductiai and error analysis programs to JPL and is currently working with them to determine the optimum data reduction procedures. Incor- poration of altimeter data for orbit deter- mination, length of data arcs, and "multi- arc" methods are some of the topics current- ly being studied jointly between JPL and NOS/GRDL. Determination of a SEASAT-A gravity model obviously cannot begin until the satellite is launched. Information obtained from GEOS-3 altimeter studies will be very valuable in determining geopotential harmonic coefficients. However, SEASAT-A will be sensitive in its own unique way to perturbations from resonant terms. Prior to the launch of SEASAT-A, analyses will be performed to determine the geopotential model terms that will probably have to be estimated or improved for adequate ephemeris calculations. A proper modeling of the SEASAT-A area-to- mass function must be developed so that the effects of solar radiation and drag acceler- ations can be adequately evaluated. Unlike most geodetic satellites, SEASAT-A will have large pitched panels which may act as wings giving the satellite lift. This phenomenon will be analyzed to determine if the force function must be modified to account for this effect. Once the tracking station complement has been determined, the LAGEOS satellite, which was launched in 1976, is to be used for pre- cise determination of the SEASAT-A station locations. Since only laser tracking is available on LAGEOS, surveys will be made to tie the non- laser sites to any nearby laser sites whose coordinates can be determined from LAGEOS. During both the pre- launch and post- launch period, NOS/GRDL will continue to work closely with JPL and other agencies. IV. 2. 1.4. Polar Studies. Because of the proposed orbit of SEASAT-A, data will not be available from the Arctic Ocean or from the seas adjacent to Antarctica. However, data availability is expected for the north coastal Alaskan area as well as the Bering Sea and the Gulf of St. Lawrence. If the Canadian station is included, sea ice data may also be obtainable from the Labrador Sea and the Baffin Bay/Davis Strait area. Sup- plementary data will be used from the SMMR on NIMBUS-G for study of the higher latitude regions. The SAR will obtain the first space acquired radar data of sea ice, afford- ing opportunity for development of new tech- niques and better understanding of sea ice distribution and behavior. The SMMR on SEASAT and NIMBUS-G will provide new data to continue experiments started with the 19.35- and 37-GHg microwave data obtained by NlMBUS-5 and NlMBUS-6, respectively. IV. 2. 1.4.1. Ice dynamics. The objectives of this study are to (1) determine the quantitative accuracy and detail with which sea ice can be mapped employing the SAR and SMMR data from SEASAT-A and NIMBUS-G, (2) assess the capabilities of SAR and SMMR to collect the required "all-weather" tem- poral data for sea ice dynamics measure- ments, and (3) apply the multisensor- multispectral capabilities of SEASAT-A and NIMBUS-G to classification of ice types and distribution of features such as ridging and open water areas . The application of remote sensing tech- niques for acquiring sea ice data in inac- cessible polar areas has been studied for more than a decade. Attempts to obtain and interpret side- looking airborne radar (SLAR) imagery were made in the early 1960's; re- search in the interpretation of multispec- tral sea ice imagery in the visible and near infrared took place in the late 1960's. About the same period, a laser profilometer was used to obtain observations on surface roughness of sea ice. The first high- quality passive microwave data on sea ice was obtained in the spring of 1970. A considerable amount of these early remote sensor studies used aircraft to obtain data. Also, most of the studies involved interpretation of imagery since very little "surface truth" was available for verification. With advances in sensor development, the NOAA satellites [with the scanning radiometer (SR) and the Very High Resolution Radiometer (VHRR)] and LANDSAT with multispectral image- ry of even highe'r resolution were employed in sea ice studies and in conjunction with pro- grams such as BESEX and AIDJEX and their asso- ciated surface truth data. The data were employed to make quantitative investiga- tions of ice drift and deformation as well as to classify ice types, etc. Although microwave data were available on a limited scale, most of the satellite imagery was limited by clouds or to daytime observations. The availability of SAR and SMMR on SEASAT-A and SMMR and CZCS on NIMBUS-G affords an opportunity to further the study of sea ice dynamics. Although SEASAT-A will be limited in coverage to about 75°N, the Bering Sea and the north coast of Alaska IV-10 will be in view for study. Also, if the Canadian station for SAR reception is installed at St. Johns, Newfoundland (or, preferably, Frobisher Bay, NWT) , the highly variable ice packs in Baffin Bay/Labrador Sea area will be within the data collection capability of SAR. Data (SAR, SMMR, and SR) will be collected periodically in the Bering Sea and along the shear zone on the north coast of Alaska dur- ing the winter season and at a higher fre- quency during the transition periods, par- ticularly in July wnen the fast ice break- up occurs along the north coast of Alaska. These data will be analyzed in conjunction with data obtained from the proposed shore- based radar at Tin City, Alaska (Campbell, USGS) . In addition, the NASA Convair 990 will obtain sea ice data as part of the Polar Ice Studies Program during 1978- 1981 (Campbell, USGS; Gloersen, GSFC) . Pre- liminary SAR data may also be obtained during aircraft tests in 1977, and these data will be analyzed during the pre-launch period. IV. 2. 1.4. 2. loe mapping. A primary objec- tive using the 37-GHz SMRR data on both SEASAT-A and NIMBUS-G will be a continua- tion of the series of weekly polar area ice mosaics in both hemispheres that was begun with the NIMBUS- 5 ESMR data. Another objective is to explore synergis- tic use of low resolution VHRR-VIS and IR data as well as very high resolution SAR data for maximizing the ice information content of space data. The capability for broad-scale mapping of pack ice in the Arctic and Antarctic has been greatly improved in the past several years by the virtually all-weather observa- tions from the 19.5-GHz ESMR on NIMBUS-5 and the 37-GHz version on NIMBUS-6. The rela- tively coarse resolution of these microwave data (about 25 km) has precluded almost any delineation of ice features other than the main pack edge and very large polynyas. These observations have, nevertheless, been found quite useful by such groups as the Navy Five Ice Unit because of the limited coverage of other satellite observation re- sulting from cloudiness or (in the case of LANDSAT) orbital and sensor factors. It has been demonstrated with ESMR data that information on ice pack concentration and differentiation between first -year and multi- year ice are derivable from such microwave measurements . The satellite ice chart series based on SMR data should be continued using SMMR data, because seasonal and annual variations of ice over an extended period are needed for oceanographic, meteorological, and climatological purposes (e.g., global circu- lation and climate models). Studies related to ice pack concentration and ice type have been hampered by lack of surface or low-altitude aircraft observa- tions, and it is expected that the extremely high-resolution SEASAT-SAR data over ice areas will overcome this limitation. SAR data coverage of ice areas will be limited, however, so comparative studies with broader and more frequent coverage but coarser- resolution might well reveal useful syner- gistic type relationships. Data taken dur- ing the freeze-up period, the period of maximum cover and thickness, and the period of rapid melt and breakup are desired. IV. 2. 1.4. 3. Sea ioe statistics. The diffi- culties encountered during the sealift oper- ations on the north coast of Alaska during 1975 indicated a need for better statistical information on the removal of the shorefast ice and the behavior of the ice pack. SEA- SAT-A affords an opportunity to establish criteria for routine collection of sea ice data under all weather conditions. Indica- tions are promising for a continuing system of acquiring the needed data for such a sta- tistical treatment (a climatology) of ice information. This study will involve the derivation of statistics from the SEASAT-A sensor data for relevant sea ice parameters (age, open water features, ridging, freezeup and break- up in coastal areas, etc.) leading to com- pilation of an atlas for use in operations in areas where little or incomplete informa- tion is currently available. The study will involve the use of archived data to establish a basic climatology of sea ice in selected areas. Techniques would be developed to extract selected information from the data and integrate them into exist- ing data banks for use as a base for future compilations and improvements. IV. 2. 1.5. Hydrology. Although SEASAT sen- sors were not designed for hydrologic appli- cations, a careful examination of the SAR and SMMR data should be made for potential usefulness in snow, ice, and soil moisture applications. Just as LANDSAT has proven oceanographic applications, SEASAT can be expected to have hydrologic applications. IV.'2. 1.5.1. Snow areal extent. The SAR will be used as a snow mapping instrument to demonstrate its usefulness as a through- the-clouds snow sensor. The SMMR sensors on SEASAT and NIMBUS-G will be evaluated for broad-scale continental and hemispheric snow- cover mapping. Although snow mapping by satellite has been accomplished since 1967, IV- 11 only recently has it become operational. The inability to map snow during cloudy intervals with this system is especially vexatious, and the usefulness of SAR and SMMR to map snow is worthy of serious ex- perimentation . IV . 2 . 1 . 5 . 2 . Snow depth and physical proper- ties. The radar data from the 13.9-GHz Radar altimeter and the SAR will be exam- ined to determine their potential for meas- uring certain physical properties of snow. The broad- scale SMMR data will provide only limited information on snow. Experiments have been carried out on sur- face vehicles in which active and passive microwave signals were used to measure the thickness of a snow course. Further, atten- uation of the radar signal by the snowpack is related to snow density and snow "wet- ness." Ground collected snow data at selected NOAA test sites will be compared with the Radar Altimeter, SMMR, and SAR data. IV. 2.1.5.3. Flood inundation mapping . With the SAR, it is expected that we can demon- strate the most precise flood maps thus far prepared from satellite data and with cloucfy conditions. One of the problems commonly encountered in flood inundation mapping is that the flooded area is overcast during the flood. Owing to the limited area of obser- vation by the SAR and the unpredictable na- ture of floods, scheduling of this demon- stration will be serendipitous. IV. 2. 1.5. 4. Soil moisture. The main pur- pose of the soil moisture experiment will be to investigate and evaluate the NIMBUS-G and SEASAT SMMR data with regard to near- surface soil moisture over selected test sites. Soil moisture is an important, currently unmeasured variable in flood forecasting models. Passive, multifrequency microwave sensors, such as SMMR, have shown in past ground- level and aircraft experiments that they respond to changes in soil moisture at or very near the surface. Surface-truth data will be compared with concurrently collected microwave data. IV. 2. 2. Demonstration The demonstration program is concerned with tests involving the direct application of SEASAT-A data to ongoing operational products. Certain experiments, which in- volve improvement of products using SAR data, will be done retrospectively (10 days) because of the expected delay in processing these data. Unlike the research program. the nature of the demonstration program has most of the activity concentrated in the post-flight period. IV. 2. 2.1. Meteorology. The ability of NOAA to provide the required level of oceanic services is hampered by a lack of observa- tional data in the marine environment. The SEASAT-A is designed to measure certain of the variables needed for marine weather analysis and prediction. Tlie purpose of these meteorological demonstration elements is to test the impact of the SEASAT-A data on operational models and environmental services/products and to evaluate the poten- tial utility of an operational SEASAT program. IV. 2. 2. 1.1. Data acquisition and valida- tion. The objective of this task is to receive SEASAT-A data in near-real-time from FNWC, Monterey, in a format compatible with the operational forecast models that will be used to evaluate potential opera- tional utility. It is expected that the models currently being developed for the First GARP Global Experiment will be used. Close liaison will be needed betwen NMC, FNWC, and JPL so that characteristics of the operational forecast models will be well known by the FNWC and JPL staffs who are responsible for converting the SEASAT data to usable geophysical units. As soon as geophysical data are available from SEASAT- A, NMC will begin the validation procedure-- initially in concert with FNWC. SEASAT-A winds will be plotted and compared visually with nearby conventional wind observations and satellite cloud motion observations. As the data become available in near-real- time from FNWC, they will be tested statis- tically with computer programs for consis- tency with nearby conventional observations from weather ships and buoys for spatial coherence, for characteristics in the pres- ence of clouds, and to determine spatial error patterns. These tests will permit NMC to identify and delete those observations that appear to be grossly inconsistent or suspect. In addition, NMC will obtain selected data sets from JPL for backup and possibly for additional data impact tests should the JPL sets differ significantly in quantity or quality from the real-time data sets. IV. 2.2. 1.2. Global atmospheric model appli- cations. The objective of this demonstra- tion experiment is to assess the impact of wind data from the SASS on global, 36- to 72-hour atmospheric forecasts. Global atmospheric sounding data from the NOAA satellite system is available routinely to the forecast models. Sounding capability IV-12 was added to the satellite system to improve the accuracy of the 36 to 72 hour atmospheric forecasts. To date, these remote soundings have not had a noticeable impact on forecast accuracy. An accurate analysis of surface pressure conditions is needed to use the remote sounding data effectively. Current information on surface pressure distribution over oceans, particularly in the Southern Hemisphere, is inadequate for this purpose. Wind measurements from the SASS may permit an accurate surface wind analysis over oceans from which an adequate surface pres- sure analysis may be derived. Data sets, one consisting of data used routinely in the operational forecast models and one consisting of the operational data set plus SEASAT-A data, will be compiled in real-time as the SASS wind data are received. (A second SEASAT-A data set may be compiled after the fact from SASS wind data derived at JPL in the event problems arise in the real-time processing and transfer of these data through the FNWC.) A set of analyses and forecasts will be prepared from the set of operational data. This set will serve as the control. A set of analyses and fore- casts will be prepared for the same dates using the operational plus SEASAT-A data set. SEASAT-A impact on forecast accuracy will be evaluated by comparing the two sets of analyses and forecasts. IV. 2. 2. 1.3. Boundary layer winds — surface wind stress analysis. The objective of this demonstration experiment is to produce a surface wind stress field analysis for the Northeast Pacific--principally the Gulf of Alaska region. Surface wind stress relates directly to surface drift which in turn determines the dispersion of pollutants, nutrients, fish larvae, and other bodies suspended in the surface layer of the ocean.* Wind stress also is related directly to wave generation. Ability to forecast ocean sur- face drift will improve services to fishing and water quality programs. Wind stress analyses and forecasts, on a finer grid mesh than is now possible, may improve wave fore- cast service to shipping. Results from a limited fine mesh atmospheric model plus an estimate of the surface stress parameter will be used as a first guess to the surface wind *This demonstration element is closely related to the Nearshore Circulation Process- es research element (IV. 2. 1.1. 3) and two activities in the Living Marine Resources demonstration element (IV. 2. 2. 3.1 and IV. 2. 2. 3. 3). When this element is success- fully achieved, several demonstration prod- ucts will be available. stress field over the Gulf of Alaska region. Surface stress parameters derived from the SASS data will be added on a grid mesh of about 100 km. Observations from instrumented aircraft flights, flown in support of ERL experiments in this region, will be used to verify the resulting analysis. IV. 2. 2. 2. Oceanography. Oceanographic prod- ucts derived from satellite sensor systems have been an ongoing activity in NOAA since 1972. During this period, a limited number of products have been developed and distrib- uted to a growing user community. It is the objective of the oceanographic demonstration effort to integrate the new data source from SEASAT and to demonstrate and evaluate the improvement that this new data can provide. IV. 2.2.2.1. Wave forecasting. The object- ive of this demonstration experiment is to use wave height observations from the SEASAT- A altimeter to (a) evaluate and amend model forecast guidance from NMC in real-time and (b) verify model wave forecasts after the fact. Each of these activities may indicate ways we can improve the accuracy of wave forecasting service provided for safe ship operation. Wave height measurements ob- tained from the SEASAT-A altimeter will be sent to the Seattle Ocean Services Facility for real-time use in evaluating and modify- ing the model wave forecast guidance mater- ial received from NMC. Altimeter data from the GEOS-3 are being used now to develop techniques to do this real-time evaluation and forecast amendment. The altimeter meas- urements will be made available, after the fact, to the NWS Techniques Development Lab- oratory for use in verifying model output. IV . 2 . 2 . 2 . 2 . Sea ice chart improvements . The SAR and the microwave radiometer imagery to be obtained from SEASAT will be of comparable quality to the SLAR data from the Great Lakes and the ESMR data from NIMBUS-5 and -6. Both these data sources have been available to NESS with the SLAR data being used retrospec- tively to improve the Great Lakes Ice Analy- sis. It is proposed that both the SAR and microwave radiometer imagery be delivered to NESS 10 to 14 days after observation and be used to update and improve the analysis of Arctic Sea ice in the seas surrounding Alaska. Since the data will not be delivered in real-time, an "under-fire" test of its util- ity is not possible. However, delivery of these data within 10 to 14 days will create a realistic simulation for evaluation of the utility of SAR--the microwave radiometer to operational sea ice detection. The activity will closely relate to the ice studies in paragraphs IV. 2. 1.1. 7 and IV. 2. 1.4. IV-13 Northern Hemisphere wave model ns. The objective of this demon- xperiment is to assess the impact ta from the SASS on the Northern open ocean wave forecasts pre- MC from numerical models. Current r predicting ocean wave conditions sts of ocean wind conditions which ed from analyses based largely on om ships. These reports are not istributed--some areas have quite rts, many have none, and some are oo late to be used in the opera- ecasts. Observations from the SASS ed to provide information about ace winds that is timely and d evenly over the computational se data, when used in computer models, should increase the d reliability of ocean wind and asts, thereby improving services g, fishing, offshore oil explora- roduction, and coastal areas. Sur- ses and forecasts produced from B data sets (operational data set t composed of operational data plus inds) will be used to supply the ta sets for a data impact demon- sing the wave forecast model. Wave produced from the two data sets mpared to determine if the SASS have made a significant impression ecast, and the accuracy of the two ets will be spot checked against om weather ships and buoys. Living Marine Resources. SEASAT-A ariety of capabilities for poten- isfying needs of living marine anagers and users alike. Extended on, with its requirement for in- vironmental data, requires added o the research activities in para- l-l- Potential exists for signifi- vements in yield model forecasts utine monitoring of wind induced rrents and turbulence. Synoptic e temperatures from cloud occluded he Bering Sea may lead to a better ing of the mechanisms affecting ration. periments are identified to demon- utility of SEASAT for enhancing ment and utilization of living ources in waters of interest to States: Effects of wind induced on plankton distribution, appli- all weather sea surface tempera- rements to Bering Sea fisheries, e transport. Each experiment is o maximize participation by oups and to capitalize on planned investigations . IV. 2. 2. 3.1. Effects of wind induced turbu- lence on plankton distributions . The estab- lishment of a cause and effect relationship between surface wind field and plankton dis- tribution (and subsequently to the survival of larval anchovy) may result in the devel- opment of a prediction capability based upon satellite derived measurements of surface wind fields. The Southwest Fisheries Center of the National Marine Fisheries Service has been investigating environmental factors affect- ing the feeding regime of larval fishes in the California Current. Studies have demon- strated a direct relationship between larval anchovy survival and the concentration of plankton of a specific size. When oceano- graphic or meteorological conditions alter the normal stability of the oceanic regime and disrupt the aggregation in dense patches of larval food organisms, larval survival and the abundance of the next-year class of anchovy is probably diminished. During the period 1 September, 1978 to 1 May, 1979, the Southwest Fisheries Center will conduct monthly 5-day field surveys in the Los Angeles Bight area to determine the phytoplankton species composition and dis- tribution and to determine the structure of the water mass. SEASAT wind and sea surface temperature data will be used to determine the effect of varying wind regime upon the structure of the water mass and thence upon the species composition, abundance, and distribution of these larval fish food organ- isms. Information from SEASAT will be sup- plemented from drifting buoys and a land station. IV. 2. 2. 3. 2. Application of all-weather sea surface temperature measurement to Bering Sea fisheries. This experiment is designed to determine the usefulness of SEASAT sur- . face temperature data for fishing applica- tions in the Bering Sea. Extensive and persistent cloud cover over the Bering Sea severely limits sea surface temperature (SST) data available from con- ventional remote sensing techniques. The all weather capability of SEASAT may provide temperature information critical to the life cycle, distribution, and abundance of com- mercial species important to U.S. fishery interests. Investigators at the National Marine Fish- eries Service Laboratory at Auke Bay, Alaska, have been studying the effects of environ- mental fluctuations upon the spring and summer seaward migration of juvenile sockeye salmon in Bristol Bay, Alaska. Results show SST patterns vary significantly from year to year and appear to be correlated with shifts in the routes and timing of the seaward sal- IV-14 mon migration. Additional factors of par- ticular importance to fish and mammals of this region are the seasonal extent and persistence of ice cover and the extent of river flow into the Bering Sea. The relatively few sea surface temperature reports available, primarily from merchant ships and occasional research ships, will be used to compliment the SEASAT all-weather synoptic maps of SST over the entire Bering Sea. This information will be used to further document the relationships of tem- perature patterns to salmon migrations. An attempt will also be made to relate SST and wind data to the advance and retreat of ice cover. Studies also will determine whether outflow plumes of major rivers can be traced from SEASAT temperature data. SEASAT monitoring should provide much useful data for prediction of the movement and dis- tribution of valuable U.S. fishing stocks and marine mammals. IV. 2. 2. 3. 3. Surface layer transport. Scien- tists agree that the most critical survival period for many marine fishes is during the time of egg and larval drift. Over 90% of The objective of this experiment is to determine if SASS measurements can be used for improved estimates of wind driven trans- port. The SASS presumes a direct measure- ment of wind stress which is an essential parameter in surface transport models. The experiment will occur in three phases. The first phase will consist of a modeling program to establish the relationship of the shellfish and finfish catch in the Northern Gulf of Mexico is composed of shrimp, menhaden, and ground fish which spawn offshore and depend on surface currents to transport their eggs and larvae into estuar- ine nursery grounds (fig. IV-2) . If surface currents are unfavorable for providing this transport, the respective fishery will be severely affected. Accurate estimates of wind driven transport during critical spawning periods could serve as a basis for yield models designed to pro- vide harvest forecasts months in advance of fishing seasons. Year-to-year variations of more than 20% are not uncommon for some fish- eries, and the savings to the fishing indus- try if these variations could be accurately predicted would be substantial. LARVAL FISH (4 DAYS AFTER HATCHING) ADULT Figure IV-2. --Life cycle of the menhaden. IV-15 scatterometer backscatter to wind stress. This phase will be satisfied by the experi- ments in paragraphs IV. 2. 1.2.2. and .3. The second phase will consist of a surface current investigation relying principally on traditional techniques coupled with SEASAT-A and aircraft overflights. This second phase will be conducted concurrently with an NMFS fisheries oceanography program scheduled for the Northern Gulf of Mexico in FY 1978. Surface transport estimates derived from SASS measurements will be compared with in-situ measurements of surface transport (drifting buoys) to establish the value of SASS data for fishery applications. The third phase will consist of cataloging SASS measurements from regions of important U.S. fishing interests for comparison with traditional Ekman transport calculations and ultimately with yield data from selected fisheries (e.g., menhaden, shrimp, croaker, and anchovy) . Emphasis also will be given to evaluating small-scale wind stress dis- tributions with respect to known features in biological life cycles. This evaluation should provide insight into mechanisms affecting such characteristics as year-class strength and availability of various species. IV. 3. Interface with Other Major Programs The launch of SEASAT-A is scheduled to coincide with several major national and international oceanographic and atmospheric research programs. As such, a mutual bene- ficial relationship will exist whereby SEASAT-A will provide significant contribu- tions to the data sets to be collected and receive a significant amount of high quality surface truth data in return. IV. 3.1. International Programs. The Global Atmospheric Research Program and the Inter- national Decade of Ocean Exploration have scheduled a considerable number of ocean- atmosphere experiments during the 1978-1980 time period. In most of these investiga- tions, there are large-coverage data require- ments which can be partially fulfilled by SEASAT-A. Similarly, these large interna- tional experiments will utilize many ocean surface observing platforms which will pro- vide a significant amount of surface truth data for SEASAT-A. A listing of these international experiments and their support relationship to SEASAT-A is shown in table IV-1. IV. 2.2.4. Geodesy. The demonstration activity for geodesy is specifically directed into a geoid comparison program. The object is to obtain a determination of geoid heights, in areas of special interest off the Atlantic and Pacific Coasts of the U.S., that is independent of the method of satellite altimeter. A mesh size of 15 min- utes of arc is to be achieved--a scale size which corresponds to the 10 cm accuracy of the SEASAT-A altimeter. The gravity survey will extend seaward to as much as 800 km and will be based on existing data, the analysis of these data for detrimental gaps, and surface ship surveys to fill in these gaps. A comparison will be made in the test areas between the geoid as defined by SEASAT-A and the gravity definition. IV. 2. 2.5. Operational Satellite System. The method, considerations, and constraints on this study have been described sufficiently in the text. IV. 2. 3. Data Handling The data handling and interface require- ments between the NASA SEASAT-A Project and other users are now being determined. Beyaid the outline and mechanisms for distribution discussed in the text, no further detail can be firmly established. IV. 3. 2. National Programs In 1953, the Outer Continental Shelf (OCS) Lands Act (67 Stat. 462) was passed estab- lishing Federal jurisdiction over the sub- merged lands of the continental shelf sea- ward of state boundaries . The Act charged the Secretary of the Interior with the responsibility for the administration of the mineral exploration and development of the OCS. Subsequent to the passage of the OCS Lands Act, the Bureau of Land Management (ELM) was designated as the administrative agency for leasing submerged Federal land. The BLM environmental studies program (1) provides information about the OCS en- vironment that will enable the Department and the Bureau to make sound management decisions regarding the development of any mineral resource, (2) acquires information which will enable BLM to answer questions about the impact of oil and gas exploration and development on the marine environment, (3) establishes a basis for prediction of impact of OCS oil and gas activities in frontier areas, and (4) acquires impact data that may result in modification of leasing and operation regulations to permit more resource recovery with maximum environmental protection. Toward this end, the BLM and NOAA have entered into an agreement to jointly develop study plans for a program of environmental IV-16 Table IV-1. --SEASAT-A support relationship to international experiments International program area Estimated support from SEASAT-A Estimated support to SEASAT-A (surface truth) First GARP Global Experiment (FGGE) 1978-1979 Wind speed, magnitude, and direction (tropical) Sea surface temperature (global) Cloud temperatures (global) 30-55 ships 100-300 drifting buoys Monsoon and Indian Ocean Experiments (Monex and Index) 1. Ocean topography (Indian Ocean) 2. Wind speed, magnitude, and direction (Indian Ocean) 3. Sea surface temperature (Indian Ocean and Arabian Sea) 4. Cloud temperature (Monsoon area) 8-10 ships 1-2 aircraft X ships of opportunity Polar Experiment and International Southern Ocean Studies (POLEX and ISOS) 1. Ocean topography (50-65°) 2. Ice concentration (Arctic) 3. Wind speed, magnitude, and direction (Arctic and Antarctic) 4. Sea surface temperature (Arctic and Antarctic) 5. Ice boundary (Northern Hemisphere) X drifting buoys 2-3 ships X aircraft Polygon Mid Ocean Dynamics Experiment (Polymode) 1. Ocean topography 2. Wind speed, magnitude, and direction (North Atlantic) 3. Surface eddies and Gulf Stream boundary (Atlantic) 4. Sea surface temperature (Atlantic) 1-2 ships 1-2 aircraft North Pacific Experiment (NORPAX) and Investiga- tion of El Nino, 1978- 1980 1. Ocean topography (Pacific) 2. Wind speed, magnitude, and direction (Pacific) 3. Sea surface temperature (Pacific) 4. Upwelling areas (Tropics and Eastern Pacific) 5. Cloud temperature (Pacific) 4-6 ships 1-2 aircraft X drifting buoys X moored buoys X deep sea tide gages IV-17 data acquisition and analyses for the Alaskan OCS areas. In this regard, NOAA has created the Outer Continental Shelf Energy Assessment Program (OCSEAP) . It is a program which will require large sets of environmental baseline data and predictive information for impact assessments. Already, a significant amount of LANDSAT data has been acquired and proc- essed for interpretation of circulatory regimes, and it is anticipated that specific parameter measurements via SEASAT-A will contribute to an improved data base and information criteria for the determination of impact assessments. A listing of SEASAT- A measurements and supportive information is shown in table IV -2. The North Pacific Experiment (NORPAX) is a U.S. program to study the long-period, large- scale- interaction of the oceans and the atmosphere and to understand the processes responsible for air/sea coupling in the entire North Pacific. The program is currently in the planning phase and arrange- ments are being made to centralize a compre- hensive data base for the North Pacific that will include bathythermograph and station data, marine meteorological data, and sea level data. SEASAT-A related measurements are listed in table IV-2. The implementation of the SEASAT-A research and demonstration program will provide an essential input to climate studies in general and to the National Climate Program in par- ticular. Dominant factors in interannual climatic fluctuations are the dynamic proc- esses that take place within the oceans and between the oceans and atmosphere. This was emphasized in the GARP Report No. 16, Pkysiaal Basis of Climate and Climate Modeling, by the Joint Organizing Committee of the Global Atmosphere Research Program and in Understanding Climatic Change, pre- pared by the National Academy of Sciences. SEASAT-A, with its sensors dedicated to ocean measurements, will provide a unique opportunity to study the feasibility of making global oceanic measurements (which are a requirement for understanding climatic changes) and to apply these measurements to analytical studies of ocean dynamic processes. In particular, the dynamics of heat content and heat transport in the oceans will be Table IV-2. --SEASAT-A support relationships to National programs National program area Estimated support from SEASAT-A Estimated support to SEASAT-A (surface truth) Outer Continental Shelf Energy Assessment program (OCSEAP) Sea ice - distribution, type, fractures Surface winds - velocity, direction Surface waves - length, height, direction Surface oil - distribution North Pacific Experiment (NORPAX) Atmospheric profiles of liquid and vaporous water Sea surface temperature National Climate Program (NCP) Sea surface temperature Surface winds Surface waves Atmospheric profiles of liquid and vaporous water STORMFURY Surface winds, wave spectra and height in a hazardous endeavor IV-IS examined to see if these quantities can be predicted. SEASAT sensors will improve the measurement of sea surface temperatures sig- nificantly over existing satellites, and the techniques developed will increase the pre- cision of measurements even further. When coupled with subsurface measurements of heat content and transport, these SEASAT data will begin to yield an understanding of climate prediction. Other SEASAT instrumentation will provide data on the interaction of the ocean with the atmosphere (e.g., the deriva- tion of wind and waves) and will allow for investigation into the transfer of heat between the oceans and the atmosphere. This SEASAT technology and technical development will be important to the future success of climate investigation and the development of methods to predict inter- annual climatic fluctuations which have major impact on man's political, social, and economic activities. IV. 3.3. NOAA Programs The research and operational activities of several major NOAA environmental assess- ment and management programs coincide with the SEASAT-A schedule for data acquisition. These programs also have a need for large data coverage and the interpretation of large amounts of data. Planned experiments within these programs will provide for extensive in-situ platforms for data col- lection which can provide correlative infor- mation to SEASAT data sets. Relationships to the SEASAT-A and the NOAA programs are listed in table IV-3. The Marine Ecosystems Analysis (MESA) Pro- gram is concerned with describing, under- standing, and monitoring the physical, chemical, and biological processes of dis- crete marine environmental systems. The program provides information and expertise required for effective management of marine areas and analyzes the impact of natural or manmade alterations on the environment. Ongoing studies within the MESA Program are the New York Bight Project and the Puget Sound Project. The New York Bight effort has placed emphasis on problems of ocean dumping and its effect on the environment, marine life, and public health. The Puget Sound studies will be directed toward the impact of the trans- port of oil from Alaska through this region. The Marine Resources Monitoring Assessment and Prediction (MARMAP) Program is a National Marine Fisheries Service program providing Table IV-3. --SEASAT-A support relationships to NOAA programs NOAA Program area Estimated support from SEASAT-A Estimated support to SEASAT-A (surface truth) Marine Ecosystems Analysis (MESA) program Sea surface temperature Surface winds - velocity, direction Surface waves - height, length, direction Vector flow field (circulation) Ships Fixed buoys Aircraft Marine Resources Monitoring Assessment and Prediction (MARMAP) program Sea surface temperature Surface winds - velocity, direction Vector flow field (circulation ) NGS Vertical Net Adjustment program Mean sea level VLBI sites for intercomparisons of mean sea level IV-19 information needed for management and allo- cation of the nation's fishery resources. The program encompasses the collection and analysis of data to provide basic information on the abundance, composition, location, and condition of the commercial and recreational marine fishery resources of the United States. SEASAT-A altimeter data will provide an independent estimation of the position of mean sea level which will assist in the National Geodetic Survey (NGS) vertical net- work adjustment. The altimeter data, little affected by usual errors in measurement of oceanographic and geodetic parameters, will be used in conjunction with computations of mean sea level at sites of the Very Long Baseline Interferometry (VLBI) to more accu- rately determine sea surface height in the Eastern North Pacific as part of the SLOPE Project. These data are essential in estab- lishing a new National Vertical Control Net- work to resolve current discrepancies in sea level estimates.