Soil moisture retrieval and AMSR-E validation using an airborne microwave radiometer in SMEX02

Field experiments were conducted to evaluate the effects of dense agricultural crop conditions on soil moisture retrieval using passive microwave remote sensing. Aircraft observations were collected using a new version of the Polarimetric Scanning Radiometer (PSR) that provided C band and X band channels. Observations were also available from the Aqua satellite Advanced Microwave Scanning Radiometer (AMSR-E) at the same frequencies. Soil Moisture Experiments 2002 (SMEX02) was conducted over a three-week period during the summer near Ames, Iowa, an area which is dominated by corn and soybeans. Aircraft data were processed and channels selected to minimize radiofrequency interference. A preliminary comparison of he aircraft (PSR) and satellite (AMSR-E) 10.7 GHz data showed comparable brightness temperature values. Sensitivity of brightness temperature to soil moisture was observed for nearly all the ground validation sites, even under dense corn canopies. Similar sensitivities were observed for C and X band channels. These results illustrate the potential to develop soil moisture retrieval techniques for wide range of agricultural conditions using AMSR-E frequencies.