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A Prototype Physical Database for Passive Microwave Retrievals of Precipitation over the US Southern Great PlainsAn accurate understanding of the instantaneous, dynamic land surface emissivity is necessary for a physically based, multi-channel passive microwave precipitation retrieval scheme over land. In an effort to assess the feasibility of the physical approach for land surfaces, a semi-empirical emissivity model is applied for calculation of the surface component in a test area of the US Southern Great Plains. A physical emissivity model, using land surface model data as input, is used to calculate emissivity at the 10GHz frequency, combining contributions from the underlying soil and vegetation layers, including the dielectric and roughness effects of each medium. An empirical technique is then applied, based upon a robust set of observed channel covariances, extending the emissivity calculations to all channels. For calculation of the hydrometeor contribution, reflectivity profiles from the Tropical Rainfall Measurement Mission Precipitation Radar (TRMM PR) are utilized along with coincident brightness temperatures (Tbs) from the TRMM Microwave Imager (TMI), and cloud-resolving model profiles. Ice profiles are modified to be consistent with the higher frequency microwave Tbs. Resulting modeled top of the atmosphere Tbs show correlations to observations of 0.9, biases of 1K or less, root-mean-square errors on the order of 5K, and improved agreement over the use of climatological emissivity values. The synthesis of these models and data sets leads to the creation of a simple prototype Tb database that includes both dynamic surface and atmospheric information physically consistent with the land surface model, emissivity model, and atmospheric information.
Document ID
20160005125
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Ringerud, S. (Universities Space Research Association Greenbelt, MD, United States)
Kummerow, C. D. (Colorado State Univ. Fort Collins, CO, United States)
Peters-Lidard, C. D. (NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
April 18, 2016
Publication Date
September 22, 2015
Publication Information
Publication: Journal of Geophysical Research: Atmospheres
Volume: 120
Issue: 19
Subject Category
Meteorology and Climatology
Earth Resources and Remote Sensing
Report/Patent Number
GSFC-E-DAA-TN31297
Funding Number(s)
CONTRACT_GRANT: NNH15CO48B
Distribution Limits
Public
Copyright
Other
Keywords
microwave
precipitation
great plains