“达维”台风大暴雨过程熵流特征分析
Analysis of the Entropy Flow Characteristics During the Torrential Rainfall Event of Typhoon Damrey (2012)
中文摘要：
应用耗散结构理论，对2012年8月3—4日发生在河北省海岸带的一次台风暴雨过程进行诊断分析，着重分析了大气排熵指数、边界层上部平均广义相当位温与暴雨的发生和落区的关系。结果表明：副热带高压稳定少动和台风外围强盛的东南风急流造成了本次历史罕见的大暴雨局地特大暴雨天气；大气排熵指数由高值向低值的演变有利于对流的发展，从而导致对流暴雨形成；负熵流区涵盖了强对流或对流性大暴雨发生的主要区域，暴雨产生前5~6 h，有高熵空气在边界层上部聚集，暴雨区位于高熵中心附近、低空切变线和地面辐合线附近，与高熵舌伸展的区域相一致。
中文关键词：
台风暴雨，排熵指数，广义相当位温
KeyWords：
typhoon torrential rainfall, removing entropy index, generalized equivalent potential temperature
Abstract：
Based on the theory of dissipative structures, a typhoon rainstorm event, which took place in the coastal zone of Hebei Province on 3-4 August 2012, is analyzed with emphasis on the relationship between the rainfall zone and two diagnostic variables, i.e, the atmospheric removing entropy index and the average generalized equivalent potential temperature in the upper boundary. The results show that: the stable subtropical high and the strong southeast jet outside the typhoon lead to an extreme weather event, associated with local torrential-heavy rain; the removing entropy index changing from high values to lower ones denoted the development of convection leading to the formation of heavy rainfall; the negative entropy flow area covered the main area of strong convection and convection heavy rainfall, and the high entropy air converged in the top of the boundary layer 5-6 hours before the torrential rainfall occurred, also the rainfall areas located near the center of high entropy, which is consistent with the high entropy tongue stretched regions .