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Title: Regional and temporal patterns of soil moisture during CLASIC using passive microwave satellite observations

Author
item BINDLISH, R - Science Systems, Inc
item Jackson, Thomas
item WANG, Y - Chinese Academy Of Sciences
item SHI, J - University Of California

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/25/2010
Publication Date: N/A
Citation: N/A

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. The effect of atmospheric water vapor of the microwave observations was studied. Atmospheric water vapor effects are significant for high frequency microwave observations (50 K for 89 GHz and 20 K for 36.5 GHz). The effect of atmospheric water vapor decreases significantly for low frequency observations (4K for 10 GHz). Soil moisture estimates were validated using ground and meteorological observations. The estimated soil moisture was in good agreement with in situ observations (SEE=0.044 m3/m3). 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). Reliable soil moisture estimates will contribute to the study the interaction between cloud formation and land surface.