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Raindrop axis ratios and size distributions in Florida rainshafts: an assessment of multiparameter radar algorithms

Date

1998

Authors

Xiao, Rongrui, author
Chandrasekar, V., author
Bringi, V. N., author
IEEE, publisher

Journal Title

Journal ISSN

Volume Title

Abstract

Eleven penetrations of rainshafts by the University of Wyoming King Air (WKA) aircraft equipped with a two-dimensional (2-D) optical array probe are studied in coordination with multiparameter radar measurements from the National Center for Atmospheric Research (NCAR) CP-2 radar collected in a multicellular storm that occurred on August 8, 1991, of the Convective and Precipitation/Electrification (CaPE) experiment. A comparison is made between the mass-weighted mean diameter (Dm) and rainrate (R) computed from the nine-size spectra and their estimates from multiparameter radar algorithms based on Zdr and Zh. It was found that Dm could be estimated with a mean bias of 0.07 mm and a standard deviation of 0.35 mm. Rainrates (in the range of 10-60 mmh-1) could be estimated from Zh and Zdr with a mean bias of 1-4% and fractional standard error (FSE) of 30-40% depending on the estimator used. Raindrop axis ratios are analyzed as a function of volume equivalent spherical diameter (Deq) in the range 2-6 mm. The mean axis ratio versus the Deq relationship was found to be consistent with previous data from the High Plains (from Colorado and Montana). A study of fluctuations of axis ratio (about their mean value) showed that most drops have axis ratios close to their mean values with oscillation amplitudes to be typically ±10% in axis ratio, again consistent with the earlier High Plains results.

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Subject

size distributions
raindrop
radar
multiparameter

Citation

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