The Relationship between the Onset Date of Preceding Winter and Following Summer Rainfall in Eastern China

By using NCEP/NCAR reanalysis datasets, the starting dates of preceding winters in eastern China have been divided from 1961 to 2010, the authors investigate the relationship between the onset date of preceding winter and the following summer precipitation in eastern China. Results indicate that there are two positive correlation bands and two negative correlation bands. The four bands are corresponding with the main rainbelts in eastern China in summer. The positive ones are located in South China, Southwest China, the region north of the Yellow River with latitudes between 39°N and 42°N, and central and southern Northeast China. The negative ones are in Huanghuai, Jianghuai, the middle and lower reaches of the Yangtze River, and most regions north of latitude 42°N. The statistical results show that the frequency of rainfall pattern II is larger than that of the climate state, those for both rainfall patterns I and III are less than that of the climate state when earlier preceding winters come. While for later winters, that for pattern I is larger than that of the climate state, those for both rainfall patterns II and III are much smaller than that of the climate state. The rainbelt outcomes from the statistics and composition analysis in the typical years are consistent with each other. The statistical results show that the later preceding winters are prime when it is pattern I, earlier winters for pattern II, and there is not significant relationship between the winter starting dates and pattern III. In a word, the patterns of precipitation are closely related to the starting dates of the seasons. The different starting dates of winters are corresponding to different air-sea interactions which result in different patterns of precipitation.