一次远距离台风暴雨过程的熵流指数演变

EVOLUTION OF THE ENTROPY FLOW INDEX IN A STORM RAINFALL FAR FROM A TYPHOON

应用耗散结构理论,结合河南省一次远距离台风暴雨过程,分析了大气排熵指数、边界层上部广义相当位温及广义相当位温平流等三个熵流指数与暴雨的发生和落区的关系,得到: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;暴雨落在大气排熵指数负值中心或负值轴线附近区域;远距离台风暴雨产生前,有高熵空气在边界层上部聚集,边界层高熵中心往往与暴雨落区对应;边界层上部高熵平流的移向往往预示了强降水的未来移向。

Based on the theory of dissipation structure,one weather process of storm rainfall far from a typhoon was taken into account and the relation between the entropy flow index and the placement of heavy rainfall was analysed. The results show that the evolution of remove entropy index from high value to low one helps develop convection and leads to the heavy rainfall formation. The placement of storm rainfall is always in the negative center of the remove entropy index or the area nearby its axes line. High entropy air will be accumulated at the top of boundary layer before the storm rainfall far from a typhoon occurs. The high entropy center always accords with the placement of rainfall. The motion direction of high entropy advection at the top of boundary layer indicates the future placement of the heavy rainfall.