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Fitting VAD winds to aliased Doppler radial‐velocity observations: A global minimization problem in the presence of multiple local minima
Author(s) -
Xu Qin,
Nai Kang,
Wei Li
Publication year - 2010
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.589
Subject(s) - maxima and minima , aliasing , radial velocity , minification , radar , azimuth , doppler effect , classification of discontinuities , computer science , doppler radar , geodesy , geology , algorithm , mathematics , filter (signal processing) , physics , geometry , mathematical analysis , computer vision , mathematical optimization , telecommunications , stars , astronomy
When the horizontal vector wind is estimated by the traditional velocity azimuth display (VAD) analysis from radar radial‐velocity observations on a selected range circle, the observations should be thoroughly de‐aliased first. When the effect of aliasing is formulated into the cost function, the VAD analysis can be applied to raw aliased radial‐velocity observations, but the minimization problem for the VAD fitting is complicated by the multiple local minima caused by the zigzag‐discontinuities of the aliasing operator. An efficient two‐step VAD algorithm is thus developed in this paper to find the global minimum in properly transformed subspaces of the VAD wind parameters. The algorithm is then extended into a three‐step volume velocity processing (VVP) method to estimate the vertical profile of horizontal winds from each volume of radar radial‐velocity scans. Examples are presented to illustrate the capability and robustness of the method. Copyright © 2010 Royal Meteorological Society