LONG-RANGE WEATHER ANALYSES OF THE CHANGE OF FOOD YIELD OVER TAI HU PLAIN

In this paper, the climatic background of high or low yield in the food production over Tai Hu Plain is analysed on the basis of yield and meteorological data in the period 1960-1979. Both relational types of the high yield/less rainfall years and low yield/more rainfall years are indicated. Furthermore, the 500 mb circulation patterns of both relational types are analysed comparatively. The middle-high latitude area in North America-Greenland can be treated as a key area of circulation evolution. It is possible to show the difference of circulation patterns of high or low years using the west wind index of this area. Finally, the relationship between the food yield in the region and the yearly change of the monsoon over Easten Asia is discussed.