压能、湿焓场与暴雨落区的诊断分析

Diagnostic Analysis on Pressure Energy, Moist Enthalpy and Occurrence of Heavy Rainfall

通过分析压能场与湿焓场的分布特征， 讨论了它们对暴雨发生可能产生的影响。这种影响实质上是由于动力学与热力学的相互作用所造成的。在本文分析的暴雨个例中， 暴雨过程都与等压能线密集带和等湿焓线密集带有一定联系， 在暴雨发生前２４ ｈ一般有强的正湿焓平流， 暴雨主要落区一般出现在平流最强的地方。因此， 分析压能场与湿焓场可以获取一些新的信息， 这对提高暴雨的预报能力可以起到一定的作用。

The distribution characters of pressure energy field and moist enthalpy field were analyzed, and their possible influences on the occurrence of heavy rainfall also were estimated. It shows that there exists a strong dynamic and thermodynamic interaction in the processes of heavy rainfall. The analyzed results show that there were some close relationship between all the heavy rainfall cases and the density isograms bands of pressure energy and moist enthalpy. Usually, there was a strong positive moist enthalpy advection that appeared 24 hours before heavy rainfall occurring. The main heavy rainfall usually located at the area where is the strongest advection. So, it is possible to obtain some new information from pressure energy and moist enthalpy, which will be useful for improving the heavy rainfall forecasting skill.