MAPPING SOIL MOISTURE IN THE SOUTHERN GREAT PLAINS USING ERS-2 SAR DATA

Authors: OLDAK, ANNA - USDA/ARS CONTRACT; Jackson, Thomas; Dulaney, Wayne; Starks, Patrick; Heathman, Gary; ELLIOTT, R - OKLAHOMA STATE UNIVERSITY; TEJRAL, R - OKLAHOMA STATE UNIVERSITY

Submitted to: Intnl Conference On Geospatial Information In Agriculture And Forestry
Publication Type: Proceedings
Publication Acceptance Date: 8/26/2001
Publication Date: 8/5/2001
Citation: N/A

Interpretive Summary:

Technical Abstract: Soil moisture is an important hydrologic variable of great consequence in both natural and agricultural ecosystems as well as in the partitioning of radiant energy at the Earth's surface. Unfortunately, it is virtually impossible to accurately assess the spatial and temporal variability of surface soil moisture using conventional, point measurement techniques. Remote sensing, on the other hand, has the potential to provide areal estimates of soil moisture at a variety of spatial scales. This investigation evaluates the use of ERS-2 C band, vertically co-polarized, synthetic aperture radar (SAR) satellite data to provide regional estimates of surface soil moisture availability. Radar data have been acquired for three (3) contiguous ERS-2 scenes in the Southern Great Plains region of central Oklahoma from June 1999 through September 2000. Twelve (12) test sites (each approximately 800 m x 800 m) were sampled during the ERS-2 satellite overpasses in order to monitor changes in soil moisture on the ground. The radar backscatter coefficient was calculated as the average of each test field site. Landsat 5 and 7 Thematic Mapper (TM) scenes of the experimental sites that were near in time to the ERS-2 acquisition dates were also collected and processed. The TM scenes were used to monitor land cover changes and calculate the Normalized Difference Vegetation Index (NDVI). The land cover and ground truth information were used for interpretation of the radar soil moisture data.