天津地区一次对流性降水过程雨滴谱特征分析

Characteristic Analysis of a Convective Precipitation Event in Tianjin Based on Laser-Optical Disdrometer Data

激光雨滴谱仪是天津人影部门近年新引入的探测设备,它对降水过程的即时监测具有重要意义。本文基于LPM-THIES激光雨滴谱仪探测资料,对天津地区2015年7月19日的对流性降水过程进行了分析。研究显示:雨滴谱仪和翻斗雨量计所获取的逐时降水其变化趋势存在一致性,但雨滴谱仪获得的累积雨量要偏大;降水过程的时空差异性大,不同测站雨强差异明显,4站降水粒子平均直径介于0.40~0.64mm,且2.0mm以下的降水粒子占到了粒子总数的95%以上;降水时段的雨强与雷达反射率的起伏变化十分明显,雨滴数浓度基本上处于103量级;蓟县站3个时次的瞬时谱均呈现单峰型分布,且峰值位于0.5mm附近。

The laser-optical disdrometer is a new kind of measuring instrument which the Tianjin Weather Modification Office purchased in recent years.It has great influence on the real-time monitoring of precipitation.Based on the laser-optical disdrometer（LPM-Thies）data,the raindrop spectrum characteristics of a convective precipitation in Tianjin is analyzed.The analysis results show that the variation trend of hourly precipitation between laser-optical disdrometer and tilting rain gauge are well consistent.But the accumulated precipitation detected by the laser-optical disdrometer was heavier.This convective precipitation had large spatial and temporal variation.The rainfall intensity had marked differences between four meteorological stations.The average diameter of precipitation particles was between 0.40 and 0.64 mm.Raindrops with the diameters being below 2.0 mm accounted for more than95% of the total number of precipitation particles.The fluctuation of rainfall intensity and radar reflectivity was obvious,and raindrop number concentration reached 103 in magnitude basically.The instantaneous spectrums at the three times in Jixian Station presented a unimodal distribution,and the peak value was near 0.5 mm.