BOULDER--From April 22 to May 22, low-flying planes and an array of new surface gauges in the Walnut River watershed east of Wichita, Kansas, are gathering data from the lowest few thousand feet of the atmosphere, called the boundary layer. Scientists Peggy LeMone of the National Center for Atmospheric Research (NCAR) and Bob Grossman of the University of Colorado are coordinating the experiment to learn more about the interactions between the boundary layer--which strongly influences weather and climate--and the watershed.
Scientists understand most of the surface--boundary layer interactions. "The real challenge," says LeMone, "lies in translating these processes into equations that can aid weather forecasters." To do that, researchers must measure the rates of heating and evaporation at the surface, as well as how quickly air in the lower part of the boundary layer mixes with air in the upper part. The Walnut River watershed (see map) was selected for its shape, size, land-use patterns, and hydrological characteristics. In addition, the existing watershed instrumentation provides a useful historical data base.
CASES researchers will share their observations and findings not only with other scientists, but with students as well. Data collected in this first and future experiments in the multiyear project will be available on the Internet for use by students from middle schools through university graduate departments.
The University of Wyoming's King Air and the National Oceanic and Atmospheric Administration's (NOAA) Twin Otter aircraft are gathering data to supplement information from surface weather stations, weather balloons, and radar provided by NCAR and the U.S. Department of Energy's (DOE) Argonne National Laboratory. Called the Cooperative Atmosphere-Surface Exchange Study (CASES), the experiment is a joint effort by the National Science Foundation (NSF), NOAA, and the DOE.
On the ground between Eldorado and Winfield, Kansas, 12 small towers measure evaporation, heating, and friction inside a triangular area marked off by three boundary-layer profilers that measure wind speeds and temperature. The two low-flying aircraft, equipped with computers and atmospheric sensors, fly in special patterns between 100 and 10,000 feet above the sparsely populated research area. Researchers are also releasing weather balloons at noon and 3:00 p.m. daily from two of the three profiler locations.