孟加拉湾超级风暴费林对西藏强降水的影响分析

Analysis on Impact of Superstorm Phailin on Severe Precipitation in Tibet

利用NCEP/NCAR(2.5°×2.5°)再分析资料和常规、非常规观测资料,通过环境场和中尺度特征较全面细致地分析了孟加拉湾风暴费林(Phailin)对西藏特大暴雪的影响。研究表明:"费林"对强降水的影响主要是登陆减弱为低压后,低压云系分两个阶段形成三个中尺度对流云团,对流云团在南支槽的作用下上高原。而强降水的发生和南风风速的大小有直接的对应关系,西南低空急流建立后西藏南部才出现强降水,而低空急流的建立是靠南支槽的贡献。南风风速和强降水的这一重要关系为此类天气提供了预报着眼点。

Using NCEP/NCAR （2.5°×2.5°） reanalysis data, conventional and unconventional data and based on the environmental and mesoscale characteristics, this paper analyzes the impact of the superstorm ＂Phailin＂ in the Bay of Bengal on the severe precipitation in Tibet. The results show that after Phailin＇s landing, it weakens into a low pressure. The development of the low pressure clouds is divided into two stages, forming three mesoscale convective cloud cluster, which controls the Tibetan Plateau severely un- der the influence of southern branch. The occurrence of severe precipitation has direct corresponding rela- tions with the speed of southern winds. The southern part of Tibet does not see severe precipitation until the establishment of the low-level southwestern jet while the establishment of the low-level jet results from the contribution of the southern branch. The important relationship between the speed of southern winds and severe precipitation is quite conductive to forecasting such weather events.