速度谱低端法在MRR 反演雨滴谱中的应用研究
The Implementation about The Method of Low-bound Velocity Spectrum Reduce Errors in MRR Retrieval

摘要 针对微雨雷达(MRR)反演雨滴谱时, 大气垂直气流影响较大(下沉气流达到1 m/s 以上时, 反演滴径的误差超过40%)以及如何剔除垂直气流的问题, 应用速度谱低端法估计垂直气流, 将降水粒子数密度最大处的速度作为速度谱的低端, 并以此计算垂直气流的速度。为了检验这个垂直气流速度对MRR 反演的修正效果, 将与MRR 放置在一起的Parsivel 雨滴谱仪的测量值作为参考进行对比。大雨强条件下修正后的相对误差减小20%左右, 中、小雨强时修正后的相对误差减小10%以上, 说明用速度谱低端法计算的垂直气流可用于修正MRR 的反演。
Abstract Because the vertical air motion has a great impact on MRR (Micro Rain Radar) retrievals (when downdraft exceeds 1 m/s, relative errors exceed more than 40%), the velocity at maximum number density as lowbound of velocity spectrum is taken to calculate the velocity of vertical air motion. The effect on correction of the MRR retrievals by removing the vertical air motion is evaluated, and the measurements of parsivel raindrop spectrometer placed together with MRR is selected as the reference value. The results demonstrate that the relative deviation of correction retrieval reduce by 20% in the large rain rate, and by 10% in medium and small rain rate. The method of low-bound velocity spectrum is suitable for MRR.