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Title: An approach to estimate the areal rain-rate distribution from spaceborne radar by the use of multiple thresholds

Abstract

Estimates of rain rate derived from a spaceborne weather radar will be most reliable over an intermediate range of values. In forming an area average of the rain rate, an alternative to the averaging of the high-resolution estimates, irrespective of their individual accuracies, is a multiple threshold approach. The method is based on the fact that the fractional area above a particular rain-rate threshold R(j) is related to the cumulative distribution of rain rates evaluated at R(j). Varying the threshold over the effective dynamic range of the radar yields the cumulative distribution function over this range. To obtain the distribution at all rain rates, a lognormal or gamma test function is selected such that the mean-square error between the test function and the measured values is minimized. Once the unknown parameters are determined, the first-order statistics of the areawide rain-rate distribution can be found. Tests of the method with data from the SPANDAR radar provide comparisons between it and the single threshold and the direct averaging approaches. 12 refs.

Authors:
;  [1]
  1. Texas A M Univ., College Station (United States)
Publication Date:
Research Org.:
National Aeronautics and Space Administration, Greenbelt, MD (United States). Goddard Space Flight Center
OSTI Identifier:
6459297
Resource Type:
Journal Article
Journal Name:
Journal of Applied Meteorology; (United States)
Additional Journal Information:
Journal Volume: 32:2; Journal ID: ISSN 0894-8763
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; EARTH ATMOSPHERE; REMOTE SENSING; RAIN; DISTRIBUTION; PROBABILISTIC ESTIMATION; ACCURACY; GAMMA FUNCTION; RADAR; ATMOSPHERIC PRECIPITATIONS; FUNCTIONS; MEASURING INSTRUMENTS; RANGE FINDERS; 540110*

Citation Formats

Meneghini, R, and Jones, J A. An approach to estimate the areal rain-rate distribution from spaceborne radar by the use of multiple thresholds. United States: N. p., 1993. Web. doi:10.1175/1520-0450(1993)032<0386:AATETA>2.0.CO;2.
Meneghini, R, & Jones, J A. An approach to estimate the areal rain-rate distribution from spaceborne radar by the use of multiple thresholds. United States. https://doi.org/10.1175/1520-0450(1993)032<0386:AATETA>2.0.CO;2
Meneghini, R, and Jones, J A. 1993. "An approach to estimate the areal rain-rate distribution from spaceborne radar by the use of multiple thresholds". United States. https://doi.org/10.1175/1520-0450(1993)032<0386:AATETA>2.0.CO;2.
@article{osti_6459297,
title = {An approach to estimate the areal rain-rate distribution from spaceborne radar by the use of multiple thresholds},
author = {Meneghini, R and Jones, J A},
abstractNote = {Estimates of rain rate derived from a spaceborne weather radar will be most reliable over an intermediate range of values. In forming an area average of the rain rate, an alternative to the averaging of the high-resolution estimates, irrespective of their individual accuracies, is a multiple threshold approach. The method is based on the fact that the fractional area above a particular rain-rate threshold R(j) is related to the cumulative distribution of rain rates evaluated at R(j). Varying the threshold over the effective dynamic range of the radar yields the cumulative distribution function over this range. To obtain the distribution at all rain rates, a lognormal or gamma test function is selected such that the mean-square error between the test function and the measured values is minimized. Once the unknown parameters are determined, the first-order statistics of the areawide rain-rate distribution can be found. Tests of the method with data from the SPANDAR radar provide comparisons between it and the single threshold and the direct averaging approaches. 12 refs.},
doi = {10.1175/1520-0450(1993)032<0386:AATETA>2.0.CO;2},
url = {https://www.osti.gov/biblio/6459297}, journal = {Journal of Applied Meteorology; (United States)},
issn = {0894-8763},
number = ,
volume = 32:2,
place = {United States},
year = {Mon Feb 01 00:00:00 EST 1993},
month = {Mon Feb 01 00:00:00 EST 1993}
}