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Title: TEMPORAL STABILITY OF THE LITTLE WASHITA WATERSHED SOIL MOISTURE MICRONET

Author
item Cosh, Michael
item Jackson, Thomas
item Starks, Patrick
item Heathman, Gary

Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: 2/27/2004
Publication Date: 4/29/2004
Citation: Cosh, M.H., Jackson, T.J., Starks, P.J., Heathman, G.C. 2004. Temporal stability of the Little Washita watershed soil moisture micronet. Abs.35, BARC Poster Day.

Interpretive Summary:

Technical Abstract: For validation of satellite soil moisture products, such as those provided by the new Aqua satellite Advanced Microwave Scanning Radiometer (AMSR), short-term experiments are important, but long term monitoring of surface soil moisture is also a necessity. As part of the AMSR validation and calibration program, large scale networks have been installed at four USDA-ARS Watersheds throughout the country to provide ground truth. However, it is not possible to gravimetrically monitor the surface at scales sufficient for validation, therefore an innovative statistical analysis technique, called temporal stability, is being investiaged for simpler estimation of large scale averages. With 13 continuous soil moisture monitoring sensors distributed throughout the watershed, the Little Washita River Watershed in southwestern Oklahoma is an ideal watershed for validation work. The Little Washita has a rich history of soil moisture experimentation, including the recent Soil Moisture Experiment in 2003 (SMEX03). At these monitoring stations, soil moisture is measured half-hourly at a depth of 5 cm, which is closely related the depth needed for satellite validation. A temporal stability analysis revealed that the area is stable in time with respect to an average soil moisture for the time period of May 2002 to September 2003. In conjunction with SMEX03, which provided independent estimates of soil moisture, it was also determined that the network accurately estimates the watershed average. Also, outlier or unstable sites are identified for future quality control.