新疆天山山区降雨的微物理结构特征

使用GBPP-100型雨滴谱仪，于2001年6月12日至7月31日在天山北坡的小渠子气象站和牧业气象试验站，对27次降雨过程进行了雨滴谱观测，共获取了4 719个雨滴谱样本。通过观测资料分析新疆中天山山区积状云、层状云、积状-层状混合云降雨的微物理结构特征。观测分析表明，天山山区降雨雨滴的平均直径0.41~0.55 mm，以积状云最大，混合云次之，层状云最小。最大平均直径0.88~1.12 mm、平均雨强1.18~2.78 mm·h^-1、平均含水量5.23~11.62 g·m^-3，混合云的这三个特征量均为最大。三类云的雨强与数密度呈正相关。积状云、层状云降雨的雨滴谱服从M-P分布，混合云服从Γ分布。由于山区地形的作用，使云中降雨粒子的生长时间受到限制，天山山区降雨小滴浓度高、尺度小，人工降雨潜力大。

Micro-structural characteristics of raindrop spectra of precipitation in the Tianshan Mountains

Using GBPP-100 Surface Raindrop Spectrometer (PMS Co.), 27 rainfall events were monitored continuously from June 12 to July 31, 2001. A total of 4 719 raindrop spectrum samples was obtained in Xiaoquzi Weather Station and animal husbandry weather test station on the north slopes of the Tianshan Mountains. Micro-structural characteristics of raindrop spectra of cumulus, stratus and merging cloud precipitation processes in the Tianshan Mountains were analyzed based on these observation data. Observation and analysis showed that the average diameter of the raindrops of precipitation in the Tianshan Mountains was 0.41~0.55 mm. Diameter of the raindrops of the cumulus cloud was the maximum, followed by the merging cloud and then by the stratus cloud. In addition, the maximum average diameter of raindrop was 0.88~1.12 mm, the average rainfall intensity was 1.18~2.78 mm·h^-1 and the average water content was 5.23~11.62 g·m^-3. These three characteristic values for stratus cloud were the maximum. Furthermore, rainfall intensity of the three clouds was positively correlated with number density. The raindrop size distribution of cumulus and stratus cloud followed M-P distribution, while that of merging cloud followed Γ distribution. Due to mountainous terrain, the growth time of precipitation particle in cloud was limited. Therefore, the high concentration and small-scale of the rain droplets in the Tianshan Mountains make artificial rainfall has great potential.