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United States Department of Agriculture

Agricultural Research Service

Research Project: Dual Assimilation of Microwave and Thermal-Infrared Satellite Observations of Soil Moisture into Nldas for Improved Drought Monitoring

Location: Hydrology and Remote Sensing Laboratory

2013 Annual Report

1a.Objectives (from AD-416):
To improve model predictions of soil moisture, evapotranspiration and surface runoff used for operational drought monitoring by assimilating remotely sensed signals of soil moisture conditions derived from microwave and thermal band satellite imagery.

1b.Approach (from AD-416):
Assemble remote sensing thermal and microwave remote sensing soil moisture datasets covering North America for 2003-present. Quantify incremental improvement in LIS-Noah model predictions of soil moisture obtained by assimilating thermal and microwave signals and develop optimized assimilation strategy. Compare moisture anomalies from optimized system with standard drought metrics: including operational NOAA drought products, U.S. Drought Monitor drought classifications, and known drought/flooding events.

3.Progress Report:

The primary objectives of this project are to.
1)generate soil moisture estimates from thermal infrared (TIR) and microwave (MW) band satellite imagery for assimilation into the National Land Data Assimilation System (NLDAS);.
2)execute a sequence of data assimilation experiments involving single assimilation of TIR and MW soil moisture estimates, and then demonstrating the value added by dual assimilation of both TIR and MW data; and.
3)optimize the formalism for deriving the TIR-based soil moisture estimate.

In Year 2 of this project, the primary accomplishments were to perform a detailed intercomparison of TIR and MW soil moisture estimates with model output from the NLDAS system. Regions of significant NLDAS-satellite discrepancy were identified and addressed to the extent possible, in many cases by moving toward input data fields that were more consistent between modeling systems. Remaining discrepancies have been evaluated for physical basis, revealing important differences in model capabilities to accurately retrieve soil moisture over irrigated land areas and regions influenced by shallow water table. These critical findings are being summarized in a manuscript for submission to a peer-reviewed journal.

Last Modified: 9/3/2015
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