Soil Moisture Retrieval Using ALOS PALSAR: CLASIC Results

Thomas Jackson(1), R Bindlish(1), R. Sun(1), S. Yueh(2) and S. Dinardo(2)

(1) USDA ARS, 10300 Baltimore Blvd., Beltsville, MD 20705, United States
(2) NASA, JPL, Pasadena, CA, United States


This project is evaluating the potential use of L-band PALSAR observations for estimating high resolution soil moisture. PALSAR data are being acquired over sites, primarily watersheds in the U.S., which have been instrumented for in situ soil moisture measurement. In addition, several more intensive field campaigns are being conducted that will provide enhanced ground and aircraft observations. The Cloud Land Atmosphere Surface Interaction Campaign (CLASIC) took place in the Southern Great Plains, Oklahoma during June 2007. Land cover conditions include a range of dryland and irrigated agricultural conditions and grazing land. Record precipitation was observed over Oklahoma during June 2007 resulted in wettest conditions ever observed. A Passive Active L-band System (PALS) was installed on an aircraft and flown on multiple dates. PALS is a fully polarimetric radar along with a dual polarization radiometer and was operated at an incidence angle of 40o. The center operating frequency of PALS is 1.26 GHz. During the one-month long field campaign, PALSAR data was available for 2 days for two different sampling regions (June 9 – Forest site; July 1- Little Washita watershed). Field average PALSAR observations were compared with field average PALS observations. Comparison of data collected over test sites indicates comparative calibration and possibly linear scaling. Current research is focused on developing soil moisture retrieval algorithms and comparison with ground observations. Efforts will also be made to develop integrated radar-radiometer soil moisture algorithms using PALS radiometer and PALSAR radar observations. With the recent approval of the Soil Moisture Active Passive (SMAP) satellite mission by NASA, there is great interest in utilizing PALSAR data to develop and validate potential retrieval methodologies.


Symposium presentation


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