Code 610 Seminar: Mircea Grecu

GEST/UMBC, Code 613.1
Abstract: Precipitation estimation from single-instrument satellite microwave observations is an ill-posed problem, i.e. no unique solution insensitive to errors in the input data exists. Traditionally, to make this problem well-posed, additional information from independent instruments and/or cloud-resolving models is incorporated into the solution. In this presentation, I will describe an algorithm to derive well-determined precipitation estimates by combining satellite radar and microwave radiometer observations. Results from the application of this algorithm to observations from the Tropical Rain Measuring Mission (TRMM) will be presented. A major benefit of combined satellite-radiometer retrievals consists of the fact that they facilitate the development of enhanced retrievals of precipitation and latent heating from radiometer-only observations. Examples of enhanced radiometer-only retrievals will be provided. Cloud resolving models represent tools to further condition and enhance satellite retrievals. Although computationally expensive and potentially deficient in representing precipitation processes, cloud resolving model can reduce the number of assumptions needed in combined retrievals and provide insight into variables that are not directly related to satellite observations. Moreover, methodologies to extend combined satellite radar-radiometer retrievals to incorporate cloud model information exist. A new methodology based on an ensemble filter, as well as results from its application and its relationship to data assimilation, will be presented and discussed. Biography Dr. Mircea Grecu received a B.S. degree from the Technical University of Civil Engineering, Bucharest, Romania in 1993, and a M.S. in civil engineering from the University of Iowa in 1996, followed by a Ph.D. from the same university in 1999. After a Postdoctoral association with the University of Connecticut, he joined Goddard Earth Sciences and Technology Center in 2002. His research interests include rainfall estimation from space and ground observations, assimilation of vsatellite observations in atmospheric models, and cloud modeling. Dr. Grecu is currently involved in the Precipitation Measuring Mission (PMM) project at the Mesoscale Atmospheric Processes Branch of NASA GSFC. His work is focused on the refinement and extension of algorithms for rain estimation from combined radar-radiometer observations.