青藏高原东部“7·8”区域性暴雨特征分析

本文利用常规观测资料和NCEP再分析资料分析了2013年7月7日20时~8日20时发生在青藏高原东部的一次区域性暴雨过程。分析结果表明:(1)青藏高原北部的切变线是此次暴雨的主要影响系统,高原西南气流加强是此次暴雨的直接诱因;(2)高原东部低层辐合、高层辐散的配置和较强的上升气流为此次暴雨提供了动力条件,高原上高温、高湿的大气状态为此次暴雨提供了较好的热力条件;(3)高原"湿地"和西南气流建立的水汽通道为此次暴雨提供了充沛的水汽条件;(4)高原东部西南气流中气流轴的位置对这次暴雨落区和落点有较好的指示意义,青藏高原东部强西南气流轴的左前方正好是阿坝州暴雨发生的区域。

Signature Analysis of a Regional Rainstorm in Eastern Tibetan Plateau on July 8th

Using the routine observation data and NECP reanalysis data , a case of a regional rainstorm occurred in Eastern Tibetan Plateau from July 7th to 8th, 2013 was analyzed. The results show that：the shear line in northern Tibetan Plateau was the major affecting system and the strengthening of outhwesterly airstream was the direct infection. The coordination of convergence at the low levels and divergence at the high levels, which resulted in strong updraft motion, provided favourable ynamicconditions for this rainstorm. At the same time, the high - temperature and high - energy atmosphere provided suitable heat conditioris. Abundant water vapor condition was provided by the Plateau ＂wetland＂ and the water vapor channel that established by Southwesterly airstream. The position of air shaft in east plateau had a good indication of the heavy rain area and drop point. The area where Aba rainstorm occurred was just in left front of the southwest iet stream axis.