1.Key Laboratory of Cloud-Precipitation Physics and Severe Storms,Institute of Atmospheric Physics,Chinese Academy of Sciences;2.School of Geoscience and Technology,Zhengzhou University
位于青藏高原东北部的祁连山是石羊河、黑河和疏勒河等多条重要河流的发源地，云微物理特征对于了解该区域大气降水形成过程具有重要作用，但关于祁连山地形云的飞机观测研究很少。本文利用青海省人工影响天气办公室空中国王飞机观测数据，分析研究了祁连山2020年8月16日的一次降水层状云的微物理特征。研究表明：祁连山地区此次降水层状云的形成，与偏南气流由低海拔河湟谷地区向高海拔山区运动过程中受地形强迫抬升过程密切相关，云中过冷液态水含量最大值为1.13 g m-3。低海拔山区和高海拔山区的云物理特征有明显差别，低海拔山区由于水汽相对丰富，地形抬升形成的过冷液态水含量较高。山区不同高度粒子形成机制存在显著差异：5600 m（-5.1 ℃）层过冷液态水含量较高，冰粒子主要通过凝华、聚并生长，也存在弱凇附过程；6560 m（-9.9 ℃）层存在大量聚合状冰粒子，粒子谱拓宽明显，凝华和聚并过程起主导作用；7850 m（-17.0 ℃）层基本为冰粒子，存在大量枝状冰粒子聚合体，说明冰粒子以凝华和聚并生长为主
Located in the northeastern Tibetan Plateau, the Qilian Mountains（QM）are the main source of several important rivers including the Shiyang, Heihe and Shule rivers. The cloud microphysical properties have a critical role in understanding the precipitation formation. However, the aircraft measurements on the cloud microphysical properties over the QM are few. By using the aircraft measurement data of KingAir-350 of the Weather Modification Office of Qinghai Province, the cloud microphysical properties of a precipitating stratiform cloud event over the QM was investigated. The results show that the formation of the precipitating stratiform event was primarily produced by the terrain lifting of nearly southerly airflow from the low topographic valley area to high mountain area. The maximum supercooled liquid water content in the orographic precipitating stratiform cloud was 1.13 g m-3. The liquid water content was relatively high in low-altitude areas due to the existence of more water vapor. The formation and growth processes of ice particles varied at different altitudes in mountainous areas. At the level of 5600 m (-5.1 ℃), the formation and growth processes of ice particles primarily depended on deposition and aggregation processes with weak riming process; at the level of 6560 m (-9.9 ℃), a large number of aggregated ice particles were observed and the spectrum broadening was obvious, indicating that the dominant formation and growth process for ice particles were deposition and aggregation processes; at 7850 m (-17.0 ℃), there were almost ice phase particles with abundant aggregated dendritic ice particles, indicating that the deposition and aggregation processes were dominant at this high altitude.