
Iowa Fields
Are Focus of Moisture Detection ExperimentBy Luis Pons June 20, 2002Corn and soybean fields in central Iowa
are being viewed from land, sky and space from June 17 through July 12 as part
of a soil moisture-detection experiment that compares computer-generated
meteorological models to real conditions. According to Agricultural Research
Service hydrologist Tom Jackson, Soil Moisture Experiments in 2002 (SMEX02)
marks the first time satellites are providing soil moisture data. It is also
testing sensors aboard Aqua, a National Aeronautics and Space Administration
(NASA) satellite launched in May that
collects information on Earth's water cycle. SMEX02 involves ARS, the U.S. Department of
Agriculture's main scientific research agency, as well as NASA, the
National Oceanographic and Atmospheric Administration (NOAA) and numerous universities. The National Soil Tilth Laboratory (NSTL)
in Ames, Iowa, and the Hydrology and
Remote Sensing Laboratory in Beltsville, Md., are the ARS entities taking
part in SMEX02. More than 50 researchers, including ones from Japan and Canada, are
participating, according to NSTL director Jerry Hatfield. The goal is to verify
moisture values given by weather models by comparing them to actual readings
gathered from Earth's surface; airplanes at various altitudes; and NASA, NOAA
and European Space
Agency satellites. Soil moisture greatly influences summer precipitation over the central
United States and is key in predicting seasonal weather patterns. Improving
computer models' abilities to predict its movement will improve weather
forecasting. Sensors aboard five aircraft will get readings at altitudes ranging from
25,000 feet down to 100 feet. On land, researchers in 78 fields will measure
changes in soil water in the upper four inches of terrain. Many instruments have been placed around Kelley, Iowa, including Light
Detection and Ranging (LIDAR), which is similar to Doppler radar and can
measure moisture movement across whole fields. According to Hatfield, this experiment may provide new understanding of how
cropping-system management in the Midwest can influence weather on a large
scale. Story contacts Hydrology and Remote Sensing Laboratory Jerry L Hatfield U.S. Department of Agriculture |