A raindrop spectrum inversion method and device

Abstract

The invention provides a raindrop spectrum inversion method and device. The method includes: obtaining a first horizontal polarization reflectivity factor and a first differential reflectivity factor; the first horizontal polarization reflectivity factor and the first differential reflectivity factor are determined by Obtained from dual-polarization radar observations in the target area; based on the first horizontal polarization reflectivity factor and the first differential reflectivity factor, the first pair of the sixth-order moment of the raindrop spectrum, the seventh-order moment of the raindrop spectrum and the target shape factor are determined; according to the first The sixth-order moment of the raindrop spectrum, the seventh-order moment of the raindrop spectrum and the target shape factor are used to obtain the initial raindrop spectrum of the target area by using the pre-established raindrop spectrum model. The invention utilizes the horizontal polarization reflectivity factor and the differential reflectivity factor to obtain the pair of the sixth and seventh order moments and the shape factor of the raindrop spectrum, and further utilizes the pre-established raindrop spectrum model to obtain the initial raindrop spectrum of the target area, thereby avoiding differential propagation. The error of the phase shift rate affects the inversion of the raindrop spectrum, which improves the accuracy of the inversion of the raindrop spectrum.

Description

technical field [0001] The invention relates to the technical field of atmospheric science, in particular to a raindrop spectrum inversion method and device. Background technique [0002] In the dual-polarization radar, the raindrop spectrum of the precipitation process can be inverted by the observed polarization radar parameters. The raindrop spectrum is the distribution of the number of raindrops in a unit volume with the size of the raindrops. Raindrop spectrum inversion using dual-polarization radar is often based on a certain raindrop spectrum model, such as: constrained Gamma model, normalized Gamma model, etc. [0003] In the method of the constrained Gamma model, the so-called constraint is to assume that the shape factor (μ) and the slope factor (Λ) in the standard Gamma model are not independent, there is a certain deterministic relationship, and based on this, we can obtain The relationship between the droplet spectrum parameters and the polarization radar param...

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Problems solved by technology

However, the assumption that μ and Λ are not independent has been questioned by some scholars: the fact that μ and Λ are not independent is due to the excessive quality control of the data, especially the μ-Λ relationship in convective cloud precipitation. reliable

[0004] The existing technology (Estimation of raindrop size distribution parameters from polarimetric radar measurements. Journal of the Atmospheric Sciences, 59, 2373-2384.) determines the parameters of the normalized Gamma model according to the slope corresponding to the axial ratio relationship of the particles, so as to realize the analysis of the raindrop spectrum Inversion, although this method does not have the inversion defect caused by excessive quality control, but this method adds the difference propagation phase shift rate K DP Inverting the raindrop spectrum, but because of the K DP The error is more sensitive, and the inversion result is not ideal

Existing technology (Retrieval of the raindrop size distribution from polarimetric radar datausing double-moment normalization. Atmospheric Measurement Techniques, 10(7), 2573-2594), using X-band dual-polarization radar observation parameters, through the third and sixth moments of the raindrop spectrum When inverting the raindrop spectrum, K is also required DP participation, so when K DP In the presence of significant errors, the results obtained are often unreliable

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