| Using the day-to-day precipitation data of 60 stations in Jiangsu and 614 stations in China from 1961 to 1999, reanalysis day-to-day wind field and height data from NCEP/NCAR and SST data from NOAA. With the analysis methods of REOF, synthesis, correlation, wavelet and filter, precipitation climatic and abnormality character is studied in Jiangsu during the 1st.- 7th. May and the 1st.- Vth.October.The result indicates that the variation character of precipitation is related to the course of summer monsoon onset in the South China Sea. With its effect, the precipitation from the Ist.May to Vth.May in Jiangsu is the most during the whole spring, and Jiangsu is on the verge of the precipitation center in China. Near the 1st.-7th.October, the variation character of precipitation is related to the ridge position of the subtropical high pressure of the west Pacific. From the middle of September to the prophase of October, with the ridge southerly moving, the precipitation of Jiangsu is descendent. But the precipitation of Jiangsu isn't descendent in 1st.-7th.October because in this period, the ridge stagnates in 22-23掳 N.Jiangsu can be divided into two precipitation variation areas of south and north during the 1st.- 7th. May, and it is the same during 1st.- Vth.October. During the 1st.-7th. May, the precipitation distribution of south of Jiangsu is in phase with the middle-low reaches of the Yangtze River, while it is out of phase with the south and southwest in China. The precipitation distribution of north of Jiangsu is in phase with the drainage of Huai River and inter-Mongolia, but it is also out of phase with the south and southwest in China. The abnormal most times of precipitation of the two areas of Jiangsu is similitude, but the abnormal little times of precipitation of the south of Jiangsu is more than the north of Jiangsu. The frequency of the persistent rain is high and the frequency of persistent sun is low in north of Jiangsu, while it is contrary in south of Jiangsu. The weather of the abnormal most precipitation and the persistent rainall doesn't correspond well in the two area of Jiangsu, while the weather of the abnormal little precipitation is corresponding with the persistent sun. During 1st.- Tth.October, the precipitation distribution of south of Jiangsu is in phase with the middle-low reaches of the Yangtze River and Guangxi, while in north of Jiangsu it is in phase with the drainage of Huai River and the up-middle reaches of the Yangtze river. The precipitation distribution is all out of phase with southwest of China. The abnormal most times of precipitation of the two areas of Jiangsu is similitude during 1st.-Tth.October, but the non-precipitation times of the south of Jiangsu is less than the north of Jiangsu. The frequency of the persistent rain weather and the persistent sun weather is almost. The abnormal most precipitation is all corresponding with the persistent rain weather of the two areas in Jiangsu. Among the years of persistent sun weather, the frequency of non-precipitation weather is low in south of Jiangsu, while it is high in north of Jiangsu.During the 1st.- 7th. May, the abnormal precipitation is mostly effected by the east-westward location difference of the subtropical high pressure of the west Pacific and the trough of east Asia, while the cross equatorial flow streams at low level near 105 E almost have no effect to it. During 1st.- Vth.October, the abnormal precipitation is effected by the south-northward location difference of the subtropical high verge of the west Pacific. The effect of Bengal gulf though to the abnormal precipitation of south of Jiangsu is all strong, but it is all weak to the abnormal precipitation of north of Jiangsu during the 1st.- 7th. May and during the 1st.- 7th.October.No matter during 1st.- 7th. May or 1st.- 7th.October, the persistent rain and sun weather is all related with the quasi-biweekly oscillation of vortex.When the precipitation appears extreme abnormality during 1st.- 7th.May in the year of 1977,1985, and dur...
|
PDF Full Text Request