C波段双偏振天气雷达偏振参量标准差分析与改进

Analysis and Improvement of Polarization Parameter Standard Deviation for C-band Dual Polarization Weather Radar

摘要:

标准偏差分析方法是有效评估雷达数据质量的关键。本文采用标准差分析法对C波段双极化雷达偏振参数进行了深入分析，以找出主要影响因素并优化参数配置。通过观测实验考察了典型天气过程中极化参数标准差的改善效果。结果表明：现有观测模式对C波段偏振参数的精度较低，并且不同仰角之间存在显著精度差异。其中，在1.5°仰角处，极化参数数据的精度高于0.5°仰角处。驻留时间、脉冲重复频率和脉冲数直接影响C波段双线极化雷达极化参数的标准差。通过优化脉冲重复频率和脉冲数，在不改变观测模式的情况下，提高了在相同停留时间内偏振标准差的精度。对两个典型天气过程中极化参数标准差的分析表明，在进行参数优化之前，冰雹过程中极化标准差普遍高于强降水事件；然而，在改进后，强降水事件中极化标准差精度通常优于冰雹事件。经过改进后的观测模式在一定程度上提升了C波段双极化雷达偏振参数数据的精确性。

Abstract:

The standard deviation analysis method is crucial for effectively evaluating radar data quality. This study applies the standard deviation analysis to analyse the polarisation parameters of C-band dual-polarisation radar, identifying the main influencing factors and optimising parameter configurations. The improvement effects on the standard deviation of polarisation parameters across typical weather processes are examined through observational experiments. The findings indicate that the accuracy of existing observational modes for C-band polarisation parameters is relatively low, with significant discrepancies in accuracy across different elevation angles. Specifically, the accuracy of polarisation parameter data at 1.5° elevation is higher than that at 0.5°. The dwell time, pulse repetition frequency, and number of pulses directly impact the standard deviation of C-band dual-linear polarisation radar’s polarisation parameters. By optimising the pulse repetition frequency and number of pulses, the accuracy of polarisation standard deviation is enhanced without altering the observational mode within the same dwell time. An analysis of the standard deviation of polarisation parameters during two typical weather processes reveals that, before parameter optimisation, the accuracy of polarisation standard deviation is generally higher during hail processes than in heavy precipitation events. However, post-improvement, the enhancement in the accuracy of polarisation standard deviation for heavy precipitation events is usually superior to that for hail events. The modified observational mode thus improves the accuracy of polarisation parameter data for C-band dual-polarisation radar to a certain extent.