雷達定量降水預報研究─子計畫:利用模擬風場資料評估移動式都卜勒雷達輔助反演近地面三維風場之效益(I)
Date Issued
2005
Date
2005
Author(s)
DOI
932625Z002012
Abstract
Many Doppler wind constrains can be
obtained in multiple radars observation area,
but the three orthogonal wind components can
not be acquired in full domain. In order to
compensate the lost information of observation,
continuity equation or other constrains
combined with many Doppler wind constrains
are used. Besides, under the assumption of
certain characters of the wind field, regression
equations can be applied for representing the
wind components to reduce the unknown
numbers. Scialom and Lemaitre (1990)
addressed the concept of a three dimensional
analytical wind field and brought it into the
cost function, and thus converted the
variational problem into the regression problem
which can be solved by the least square error
method. The present research is devoted to the
application of MANDOP analysis in retrieving
the typhoon wind field and introducing the
cylinder coordinates to improve the accuracy of
the result.
The present paper adopts the cylinder
coordinates in which the center axis is typhoon
center and assumes that the analytical wind
components, with respect to each coordinate,
may be written as a product of three functions
of each coordinate. The base functions are
power series in radial, Fourier series in
tangential and Lengendre series in vertical
direction. In the respect of constrains, except
for using Doppler wind and continuity
constrains, the boundary condition at ground,
top of troposphere and typhoon center are
included.
Besides using uniform flow and vortex for
testing, the simulated typhoon Herb data,
produced from MM5 model, are used as the
real typhoon wind field. Doppler wind
observations are simulated from two to three
radars which are at different places. The wind
retrieval method above is used to evaluate the
results and the affects by comparing the
retrieval wind with the true wind under
different conditions.
Subjects
Doppler radar
3D wind retrieval
MANDOP
Publisher
臺北市：國立臺灣大學土木工程學系暨研究所
Type
report
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