Aircraft observation of cloud microphysical characteristics of pre-stratiform-cloud precipitation in Jiangxi Province

摘要

Based on Droplet Measurement Technologies data of a pre-stratiform-cloud precipitation event in Ganzhou, Jiangxi Province, on 11 November 2015, and combined with radar data, this paper comprehensively analyzes the macro- and microphysical characteristics of cloud in the upper trough. The results show that: (1) Detection takes place in the early stage of precipitation and the cloud has multiple layers. The cloud type is stratiform (Sc) and the height of the cloud base is 1009?m, 1009–1700?m is the low Sc layer, 1700–3000?m is the no-cloud level, and 3000 to the maximum height detected is another Sc layer. (2) The Sc is inhomogeneous in the horizontal and vertical directions. The particle number concentration and the effective diameter below the 0?°C layer is significantly higher than that above the 0?°C layer, which is in accordance with the ‘seeder–feeder’ mechanism. Above the 0?°C layer is seeder cloud, where needle, column ice crystals and water droplets coexist, and sublimation and coalescence are the main processes. The morphology of ice crystals changes from needle to column, plate, and polymer as height decreases. Below the 0?°C warm layer is a supply cloud, and the particles develop in the supply cloud with abundant liquid water content. Ice melting and coalescence dominate the warm layer, which makes the effective diameter significantly increase. Down to 4150?m, the ice melts completely into raindrops.摘要本文利用2015年11月11日江西省赣州市一次降水前期层状云的DMT资料，结合雷达数据，综合分析了在高空槽影响下云系的宏微观结构特征。结果表明: (1)探测属于降水前期，云系呈多层分布。(2) 层状云系在水平和垂直方向存在不均匀性， 0°C层上下满足播种云-供应云机制。0°C层以上为播种云，凝华，粘连增长占主要过程。 0°C层以下的暖层为供应云，粒子在液态水含量丰富的供应云体中长大，冰晶的融化聚并过程使得有效直径显著增大。下降到4150m的高度，冰晶完全融化变为雨滴。