Submitted to: Specialist Meeting on Microwave Remote Sensing
Publication Type: Abstract Only
Publication Acceptance Date: 1/5/2010
Publication Date: 3/1/2010
Citation: Bindlish, R., Jackson, T.J., Wang, Y., Shi, J.C. 2010. Regional temporal patterns of soil moisture during CLASIC using passive microwave satellite observations [abstract]. Specialist Meeting on Microwave Remote Sensing. 2010 CDROM. Interpretive Summary:
Technical Abstract: The Cloud Land Surface Interaction Campaign (CLASIC) was conducted in Oklahoma during the summer of 2007. CLASIC was intended to examine the mechanisms that exist between land surface variables, such as soil moisture, and the atmosphere. Record levels of precipitation were encountered during the CLASIC field experiment. This rainfall resulted in widespread and repeated flooding throughout Oklahoma and Texas. A core element of CLASIC was high resolution monitoring and mapping of soil moisture using an aircraft based sensor. However, the frequency of the rainfall resulted in temporal variations in soil moisture that could not be adequately captured using the aircraft observations.. As a result we turned to the satellite-based soil moisture information derived from the TRMM Microwave Imager (TMI) and Advanced Microwave Scanning Radiometer (AMSR-E). The TMI provides low frequency microwave data within the maximum latitude bands of coverage (+/-38o). For Oklahoma, this results in multiple daily overpasses, as opposed to the 2-3 day coverage provided by the polar orbiters such as AMSR-E. In this study, TMI and AMSR-E observations were used to study the evolution of soil moisture conditions over the Southern Great Plains and to evaluate the potential of using this data to monitor and map flooded areas. Soil moisture estimates were validated using ground and meteorological observations. Results also showed the estimated soil moisture was able to capture the precipitation patterns. The range and variability of estimated soil moisture was a function of land surface variables (vegetation and soils). Microwave indices (Polarization Ratio (PR) and Microwave Vegetation Index (MVI)) were also used to study the spatial patterns. PR is influenced by both vegetation and soil emission, whereas MVI is influenced by vegetation emission only. It is difficult to separate the vegetation effect from soil moisture variations in rapidly changing conditions. Reliable soil moisture estimates will contribute to the study the interaction between cloud formation and land surface.