青藏高原东北部地区一次强对流天气特征分析

摘要

In order to study the occurrence and development mechanism of the strong convective weather in the northeastern Qinghai-Tibet Plateau,a short-time strong convective weather occurred in the morning on August 18,2016 in the northeast of Qinghai province is characteristically analyzed by using the conventional meteorological observation,satellite cloud map,automatic station observation,NCEP 1 × 1 ° reanalysis data and the weather diagnosis method.The results show that intersection of the southwest moist and warm air flows from periphery of subtropical high and eastward and southward-moving cold air in the northeast of Qinghai province is the main cause which triggers the strong convective weather.The Ki＞ 32 ℃ region corresponds to the strong convective region.The characteristics of water vapor is dry and cold on high-level,warm and moist on low-level.water vapor flux is 6 ～ 8 g/s.Infrared images shows the structure of cloud is dense,boundary clear and approximately elliptical mesoscale convective cloud cluster.There is a good corresponding relationship between region of TBB (black body temperature) ＜-73 ℃ and large gradient value region with heavy rain fall area.%为了研究青藏高原东北部地区强对流天气发生、发展机制,利用常规气象观测、卫星云图、自动站、NCEP1°×1°再分析等资料,采用天气学诊断方法,对2016年8月18日清晨发生在青海省东北部的一次强对流天气进行特征分析.结果表明,副热带高压外围的西南暖湿气流与东移扩散南下的冷空气在青海省东北部交汇是此次强对流天气的主要成因;Ki＞32℃区域与强对流区域相对应;水汽特征为高层干冷,中低层暖湿,水汽通量在6～8 g/s;红外云图为云团结构紧密,边界清晰,近似椭圆状的中尺度对流云团,TBB＜-73℃的区域和梯度大值区与短时强降水的落区相对应.