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Cloud model-based simulation of spaceborne radar observationsSimulations of observations from potential spaceborne radars are made based on storm structure generated from the three-dimensional (3D) Goddard cumulus ensemble model simulation of an intense overland convective system. Five frequencies of 3, 10, 14, 35, and 95 GHz are discussed, but the Tropical Rainfall Measuring Mission precipitation radar sensor frequency (14 GHz) is the focus of this study. Radar reflectives and their attenuation in various atmospheric conditions are studied in this simulation. With the attenuation from cloud and precipitation in the estimation of reflectivity factor (dBZ), the reflectivities in the lower atmosphere in the convective cores are significantly reduced. With spatial resolution of 4 km X 4 km, attenuation at 14 GHz may cause as large as a 20-dBZ difference between the simulated measurements of the peak, Z(sub mp) and near-surface reflectivity, Z(sub ms) in the most intense convective region. The Z(sub mp) occurs at various altitudes depending on the hydrometeor concentrations and their vertical distribution. Despite the significant attenuation in the intense cores, the presence of the rain maximum is easily detected by using information of Z(sub mp). In the stratiform region, the attenuation is quite limited (usually less than 5 dBZ), and the reduction of reflectivity is mostly related to the actual vertical structure of cloud distribution. Since Z(sub ms) suffers severe attenuation and tends to underestimate surface rainfall intensity in convective regions. Z(sub mp) can be more representative for rainfall retrieval in the lower atmosphere in these regions. In the stratiform region where attenuation is negligible, however, Z(sub mp) tends to overestimate surface rainfall and Z(sub ms) is more appropriate for rainfall retrieval. A hybrid technique using a weight between the two rain intensities is tested and found potentially usefull for future applications. The estimated surface rain-rate map based on this hybrid approach captures many of the details of the cloud model rain field but still slightly underestimates the rain-rate maximum.
Document ID
19950037164
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Yeh, H.-Y. M.
(Caelum Research Corporation Silver Spring, MD, United States)
Prasad, N.
(Science Systems and Applications, Inc. Lanham, MD, United States)
Meneghini, R.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Tao, W.-K.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Jones, J. A.
(Hughes STX Corporation Lanham, MD, United States)
Adler, R. F.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 16, 2013
Publication Date
January 1, 1995
Publication Information
Publication: Journal of Applied Meteorology
Volume: 34
Issue: 1
ISSN: 0894-8763
Subject Category
Meteorology And Climatology
Accession Number
95A68763
Distribution Limits
Public
Copyright
Other

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