Submitted to: IEEE Transactions on Geoscience and Remote Sensing
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/9/2002
Publication Date: 10/1/2002
Citation: Jackson, T., Gasiewski, A., Oldak, A., Klein, M., Njoku, E., Yevgrafov, A., Christiani, S., Bindlish, R. 2002. Soil Moisture Using the C-band Polarimetric Scanning Radiometer During the Southern Great Plains 1999 Experiment. IEEE Transactions Geoscience and Remote Sensing, 2002. 40:2151-2161. Interpretive Summary: A new era of satellite remote sensing for hydrology will begin with several satellites scheduled for launch within the next year. These will offer new soil moisture products for hydrology and climate studies. There have been few attempts to perform large-scale validation and mapping of soil moisture using C-band passive microwave radiometry. Since C band will be a component of many future research and operational satellite missions, efforts must be made to acquire appropriate data sets. In the Southern Great Plains 1999 experiment a new aircraft instrument was used for the first time. The single channel soil moisture algorithm was evaluated using SGP99 observations. When optimized for each specific test area, the algorithm yielded excellent predictions for two of the test areas. Results obtained using the full soil moisture retrieval algorithm were also good and resulted in small increases in the error levels obtained through optimization. Regional images were found to provide correct representations of conditions. The success of the instrument and the experiment represents a significant contribution to soil moisture algorithm development and validation, which will be of value in hydrologic modeling and climate analyses.
Technical Abstract: The Advanced Microwave Scanning Radiometer (AMSR) holds promise for retrieving soil moisture in regions with low levels of vegetation. Algorithms for this purpose have been proposed, but none rigorously evaluated due to a lack of data sets. Accordingly, the Southern Great Plains 1999 Experiment (SGP99) was designed to provide C-band data sets for AMSR algorithm development and validation. Ground observations of soil moisture and related variables were collected in conjunction with aircraft measurements using a C-band radiometer similar to the AMSR sensor (6.92 GHz), the Polarimetric Scanning Radiometer with its C-band scanhead (PSR/C). The study region has been the focus of several previous remote sensing field experiments and contains vegetation conditions compatible with the expected capabilities of C-band for soil moisture retrieval. Flights were conducted under a wide range of soil moisture conditions, thus providing a robust data set for validation. A significant issue found in data processing was the removal of anthropogenic radio frequency interference. Several approaches to estimating the parameters of a single channel soil moisture retrieval algorithm were used. PSR/C soil moisture images show spatial and temporal patterns consistent with meteorological and soil conditions and the dynamic range of the PSR/C observations indicates that the AMSR instrument can provide useful soil moisture information.