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Iowa Fields Are Focus of Moisture Detection Experiment
By Luis Pons
June 20, 2002
Corn 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.
