2008年初低温雨雪冰冻灾害期间青藏高原低值系统持续活跃机制分析

运用Ncep再分析资料和常规观测资料,针对2008年1月11~24日四川盆地长时间持续的低温雨雪天气,分析巴湖低涡长时间稳定的机制,以及巴湖低涡在稳定的同时怎么使得青藏高原低值系统持续活跃,分析发现巴湖低涡维持阶段其后部的乌拉尔山高压长时间稳定的同时,前侧深厚的北风气流使得高纬对流层高层的高位涡向对流层中层的巴湖地区输送,从而促使巴湖低涡稳定并维持。在巴湖低涡稳定期间,巴湖低涡一带维持正涡度,并不断的向青藏高原东部输送正涡度平流和冷平流,使得青藏高原上空低值系统持续活跃。

The Analysis of Continuing Active Mechanism of Low-value System in Tibetan Plateau during Freezing Rain and Snow Time in Early 2008

Aiming at the long time continuing low temperature rain and snow weather in Sichuan from 11th to 24th in Jan. 2008,the information of further analysis and conventional observation data is used to analyze the long time stable mechanism of Palestinian Lake's low vortex and how Palestinian Lake's low vortex keeps the low-value system in Tibetan Plateau continuing active as well as stable.Through analysis,it is found that high pressure in Ural Mountains maintains stable when Palestinian Lake's low vortex is at its sustainable period.At the same time,the strong north airstream in the front side makes the high vortex of troposphere at the high latitude transported to Palestinian Lake Area which is at the middle troposphere.Subsequently,it Palestinian Lake's low vortex to maintain stable.During the stability of Palestinian Lake's low vortex,this area keeps positive vorticity.Meanwhile,it transports stratosphere of positive vorticity and cold stratosphere to the eastern part of Tibetan Plateau continuingly.In this condition,the low-value system in Tibetan Plateau keeps continuing active.