Tendency prediction of precipitation and inundation in July in the Sichuan Basin, China

Abstract

AbstractIn July 1981, there occurred a comparatively severe flood and inundation in the Sichuan Basin. Before its occurrence, certain precursory phenomena appeared in the May 500 mb circulation field. The Western Pacific subtropical high apparently strengthened and extended westward, the mid‐latitudinal zonal circulation weakened, whereas the meridional circulation strengthened. At the same time, the astronomical background suggested a rainy period. All these precursory features unanimously indicated the probability of heavy precipitation and a tendency for flooding and inundation in July‐August, but especially in July, in the Basin. In this paper analysis and discussion emphasize the astronomical factors, the circulation factors and the prediction instrumentation which resulted in a successful prediction.