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Affiliation: UMBC/JCET, Code 614.6 / Instrumentation Sciences Branch
Event Date: Wednesday, August 16, 2006
Location: NASA GSFC, Building 33, Room A128
Time: 11:30 AM - 12:30 PM
Passive and Active Microwave Remote Sensing of Cold-Cloud Precipitation
Precipitating clouds, over both land and ocean, are critically important to local and global climate, energy balance, and hydrologic cycles. Our understanding of cold-cloud precipitation, dominant in the middle and high latitudes, remains lacking in several areas. Microwave remote sensing techniques, both active and passive, exploit relationships between ice/water and particle sizes/shapes to both separate frozen and melted precipitation and to infer geophysical properties of interest. The process is complicated by the fact that observations are often an "integrated" response within a finite field of view, which may contain a variety of precipitation types. The research described in this talk describes an amalgamation of methods by which one can untangle the relationship between the observation and the geophysical properties of interest, such as particle size distribution or precipitation rate. Using aircraft radar and radiometer data obtained during the Wakasa Bay 2003 winter field campaign over the Sea of Japan, several rain and snow events were observed. The PR-2 active radar operated at microwave frequencies of 13.4 and 35.6 GHz, and the MIR radiometer made passive observations at 89, 150, 220, near 183, 220 and 340 GHz. A radar retrieval method based on the dual wavelength ratio technique described in Meneghini et. al., 1997 is used to infer particle size distribution properties, while simulated MIR brightness temperatures are compared to observed brightness temperatures to further constrain the radar retrievals. The result is a dataset of retrieved particle properties, such as size distribution and density, that are consistent with both simulation and observation. The techniques are being developed with an eye toward the Global Precipitation Measurement Mission (GPM). Parameterizations based on these retrievals will be used to identify and communicate the key characteristics of cold-cloud precipitation to the larger remote sensing and climate modeling community. This research constitutes a portion of the author's Ph.D. dissertation research from the University of Wisconsin.
Posted or updated: Monday, August 14, 2006
Editor: Paul Przyborski
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