山东一次暴雨过程的云降水微物理特征分析

Microphysical Properties of Cloud and Precipitation During a Rainstorm Process in Shandong Province

以2013年7月29日发生在山东的一次暴雨过程为例,利用高空间分辨率的MODIS极轨卫星资料以及布设在章丘的THIES激光雨滴谱仪连续采样获取的降水粒子谱资料,并采用Rosenfeld等提出的云微物理分析方法,对云和降水的微物理特征进行了分析。结果发现,这个暴雨云团由多种不同高度的云系组成,其中对流云团在-10℃以上存在深厚的混合相增长带和冰化增长带,冰化增长起始温度基本都在-20℃左右。系统性层云中存在凝结增长、碰并增长和混合相增长过程,但无冰化增长过程。此降水过程多次出现强度>100 mm·h^(-1)的高雨强值,最大雨滴数浓度达10~4量级,并存在接近8 mm的特大滴,降水强度与雨滴数浓度和谱宽的关系极为密切;直径>2 mm的雨滴数浓度不足1%,但对降水的贡献却占绝大多数。从雨滴谱谱型分布来看,多峰型结构所占比例最大,单峰型次之,指数型分布出现频率最少。

Taking the rainstorm that occurred in Shandong Province on 29 July 2013 as an example,microphysical properties of cloud and precipitation were investigated by using the microphysical analysis method developed by Rosenfeld and the high spatial resolution data of MODIS polar satellite and the precipitation particle spectrum data collected by the THIES laser rain droplet collector in Zhangqiu.The analyses show that the cloud cluster for the rainstorm is composed of various clouds with different heights.Deep mixed phase growth and glaciation zones exist in the convective cloud above-10℃ and the initial temperature of glaciation growth is about-20℃.There is condensation growth,coalescence growth and mixed phase growth in systematic stratus clouds but no glaciations growth.The high rainfall intensity greater than 100 mm·h^(-1)occurs several times with maximum rain droplet concentration up to 10~4,and the extremely big drop is close to 8 mm.So,there is a close relationship between rainfall intensity and rain droplet number concentration.The diameter of raindrops bigger than 2 mm is less than 1%of total concentration,but it is the vast majority of contribution to rain intensity.From the types of spectrum distribution,it can be seen that exponential distribution is less frequent,and multipeak structure has the largest proportion.