Clear-air echo automatic recognition method and system for millimeter wave ceilometer

Abstract

The invention relates to a clear-air echo automatic recognition method and system for a millimeter wave ceilometer. The method includes the following steps that: the echo data of a target region are acquired; the reflectivity factors, velocity absolute values and echo heights of different regions are put into statistics; first classification is performed on the echo data according to an initial threshold value; data about the change of the amplitude of the signals of the millimeter wave ceilometer with the time are obtained; the echo data are preprocessed according to initial input information, so that power spectrum data are obtained, a zero-crossing point is obtained according to the intersection of a mean and a filtered power spectrum, and classification is performed; second classification is performed on the echo data according to a classification threshold value on the basis of the power spectrum data; clear-space echoes and weak cloud echoes which are obtained after the second classification are subjected to spatial-scale distribution statistics; and third classification is performed on the echo data according to the discriminant threshold value of spatial scale distributiondata. With the method and system provided by the technical schemes of the present invention adopted, the influence of clear-air echoes in an atmospheric boundary layer on the millimeter wave ceilometer in a measurement process is eliminated.

Description

technical field [0001] The invention relates to the fields of atmospheric detection and atmospheric remote sensing, in particular to a method for automatic recognition of clear-sky echoes of a millimeter-wave nephelograph and a system for automatic recognition of clear-sky echoes of a millimeter-wave nephelograph. Background technique [0002] Millimeter-wave nephelometer refers to a nephelometer that uses an all-solid-state Ka-band millimeter-wave transmitter and a parabolic antenna fixedly pointing to the vertical headspace. It is mainly used to detect the reflectivity factor, vertical motion velocity and spectral width of clouds and precipitation particles, and The characteristics of cloud height, cloud thickness, and liquid water content can be obtained by inversion. However, the atmosphere in the atmospheric boundary layer directly interacts with the underlying surface, and is greatly affected by human activities, resulting in extremely strong turbulent characteristics o...

AI Technical Summary

Problems solved by technology

[0005] Another object of the present invention is to provide a clear-sky echo automatic identification system of a millimeter-wave nephelometer, which can solve the problem of cloud body identification and clear-sky echo detection when the millimeter-wave nephelometer detects clouds affected by clear-sky echoes in the atmospheric boundary layer. Echo cancellation and other issues

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