■ US- it WPL Digitized by the Internet Archive in 2012 with funding from LYRASIS Members and Sloan Foundation http://archive.org/details/wplwavepropagatiOOenvi £5$.&>OJ>'U) St WPL Advances in remote sensing have forever changed the way we observe our environment. Our ability to reach out with acoustic and electromagnetic waves has provided new insights into the behavior of the atmosphere and oceans. The Wave Propagation Laboratory celebrates its twentieth year of contributions to remote sensing. Through a blend of theory and applications, of science and technology, WPL has been able to perceive needs, conceive remote sensing solutions, and develop them for operational use. WAVE PROPAGATION LABORATORY m 1967-1987 The Boulder Atmospheric Observatory MPL's remote and in-situ sensors are being applied to a broad range of atmospheric studies. Meanwhile, the search for new techniques to probe the atmosphere and oceans continues. Our understanding of terrain effects on flows near mountain ranges and ocean channels has been advanced through coordinated computer modeling and remote sensor observations. The computer plots below illustrate the type of mutual verification possible. The distinctive eddy induced in the Santa Barbara channel by terrain features along the coast has implications for oil exploration in the channel. 1 5 H §*>s\\>y\ \\\\^ v Laser crosswind sensors monitor flow across beam paths several kilometers long. When a laser beam propagates through the atmosphere, turbulence breaks up the beam into irregular patches that move with the wind. By correlating the time delay between two adjacent optical receivers, a measure of the crosswind velocity is obtained. Laser beam after propagation through turbulent air. Two transmitter-receiver configurations lor flow measurement Radar measurement. Spatial arrays of transmitters and receivers can be devised to pinpoint measurements of transverse flow along the beam paths. Acoustic transmitters and receivers deployed in an array of moorings, transmitting sound in a criss-crossing network of paths, provide three-dimensional information on the temperatures and currents in the open oceans. The Boulder Atmospheric Observatory with its 300-m instrumented tower has served the needs of both boundary layer scientists and designers of remote sensors. Sophisticated turbulence sensors on the tower are useful for boundary layer experiments and for calibration of remote and in situ atmospheric sensors. / \ coustic and microwave remote sensors are providing detailed information on the / A \ structure of the lower troposphere for studies of events such as drainage winds, gust LJ \_A fronts, and microbursts that affect our environment, the quality of the air we breathe, and our safety. Doppler radar operating at 3-cm wavelength. Acoustic sounder measuring winds in a canyon. Echo returns from acoustic sounders trace a changing pattern of layers of laminar and turbulent air within the lowest 500 meters. With added Doppler wind-sensing capability, they measure velocity profiles of flow in canyons and drainage basins to aid in a wide variety of pollutant transport and diffusion studies. Color displays of gust fronts and microbursts from our Doppler radars allow us to analyze those hazardous events and to develop predictive tools for airport use. The radar systems operate in pairs, scanning the same spatial volume from different locations to provide information on the three- dimensional structure of the wind field. Strong downward velocities in microbursts, and the divergence created at the surface, are clearly apparent in wind field plots generated from dual-Doppler measurements made with our 3-cm radars. Vertical cross section ot wind field it a microburst. plotted from dual- Doppler measurements J \/ I ultibeam Doppler radars operating at wavelengths from 0.3 to 6 meters measure vertical profiles of horizontal winds throughout the troposphere. These "Wind Profilers" operate in the optically clear atmosphere to provide time-height cross sections of the horizontal wind field with temporal resolution ranging from 10 minutes to 1 hour. m Wind Profiler at Stapleton Airport operating at 0.33-m wavelength. Denver skyline viewed from Boulder on the evening of the second day oi the 3-day pollution episode. ewer and more powerful lidars are being deployed in field experiments to study flows within gust fronts and microbursts, over ridges and within canyons. WPL A gust front as observed by Doppler lidar (above) and Doppler radar (below) Multiwavelength lidars capable of measuring oil fog concentrations in the atmosphere have been used in controlled experiments to study plume dispersion over mountain ridges and other terrain features. Cross sections of concentrations at different points downwind of the source are obtained from vertical scans with the lidar. Oil log illuminated by a vertically scanning lidar in a study ol How over a uniform ridge. Our pulse Doppler lidar can map wind fields within long narrow canyons and city streets. The extremely narrow beam of the lidar permits wind measurement within a meter of obstacles and side walls. Vertical cross section of horizontal winds within a canyon, as measured by Doppler lidar Inlrared pulse Doppler lidar For further information: Dr. Steven F. Clifford Director, Wave Propagation Laboratory Environmental Research Laboratories 325 Broadway Boulder, Colorado 80303 (303) 497-6291 U.S. Department of Commerce National Oceanic and Atmospheric Administration Environmental Research Laboratories Q5$.(cU?'L0 St WPL Advances in remote sensing have forever changed the way we observe our environment. Our ability to reach out with acoustic and electromagnetic waves has provided new insights into the behavior of the atmosphere and oceans. The Wave Propagation Laboratory celebrates its twentieth year of contributions to remote sensing. Through a blend of theory and applications, of science and technology, WPL has been able to perceive needs, conceive remote sensing solutions, and develop them for operational use. WAVE PROPAGATION LABORATORY ■<>■ AQ0a013b0a7fl1