THE ANALYSIS OF LONG-RANGE WEATHER PROCESS OF SUMMER DROUGHT AND FLOOD IN THE HAI RIVER BASIN

Based on the monthly 500 mb mean charts during the years of 1951-1976,we have analyzed the characteristics of general circulation at summer drought and flood occasions in the Hai River basin. There were obvious different characteristics between the drought and flood. It may be summarized types of drought and flood by the zonal index. The types and some indexes relating the long-range forecast of the drought and flood are given.It was verified that the types of drought and flood are feasible, and those indexes of the long-range forecast are usefulness through the inspection in 1977-1979.