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The Role of Orograph and Parallax Corrections on High Resolution Geostationary Satellite Rainfall Estimates for Flash Flood ApplicationsThe current generation of geosynchronous satellites exhibits considerably improved capabilities in the area of resolution, gridding accuracy, and sampling frequency as compared to their predecessors. These improvements have made it possible to accurately observe the life cycle of small scale, short-live phenomenon like rapidly developing thunderstorms, at a very high spatial and temporal resolutions. While the gain in the improved resolution is not significant for synoptic scale cloud systems, it plays a major role on the computation of precipitation values for mesoscale and stonn scale systems. Two of the important factor on the accurate precision of precipitation from satellite imagery are the position of the cloud tops as viewed by the satellite and the influence of orographic effects on the distribution of precipitation. The first problem has to do with the fact that the accurate estimation of precipitation from data collected by a satellite in geosynchronous orbit requires the knowledge of the exact position of the cloud tops with respect to the ground below. This is not a problem when a cloud is located directly below the satellite; at large viewing angles the geographic coordinates on satellite images are dependent on cloud heights and distance from the sub-satellite point. The latitude and longitude coordinates for high convective cloud tops are displaced away from the sub-satellite point and may be shifted by as much as 20 Km from the sea level coordinates. The second problem has to do with the variations in rainfall distribution with elevation. Ground observations have shown that precipitation amounts tend to increase with height and that the slope of the hill or mountain that is facing the prevailing wind normally receives greater rainfall then do the lee slopes. The purpose of the study is to show the recent developments at the Office of Research and Applications (ORA) at the National Oceanic and Atmospheric Administration (NOAA/NESDIS) in Camp Springs, MD, USA, to adjust any satellite rainfall estimation technique and account for orographic and parallax corrections. Description and examples of the procedure applied to the current NOAA/NESDIS experimental satellite rainfall estimation technique for flash flood applications will be presented at the conference.
Document ID
19990103952
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Vicente, Gilberto A.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Davenport, Clay
(National Environmental Satellite Service Washington, DC United States)
Scofield, Rod
(National Environmental Satellite Service Washington, DC United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 1999
Subject Category
Meteorology And Climatology
Meeting Information
Meeting: 1999 EUMETSAT Meteorological Satellite Data User''s Conference
Country: United States
Start Date: January 1, 1999
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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