On The Influence Of The Heat Source On The Asian Summer Monsoon And The Recipitation Of China In Summer

Using the daily and monthly NCEP/NCAR reanalysis data from 1951 to 2000 and monthly precipitation of 160 stations in China in summer from 1951 to 2000, the climatic distribution of every season of heat source are computed. The laws of seasonal variation of the heat source in Asian monsoon area are analysed. The responses of Asian monsoon circulation to the heat source annual anomalies over the Bay of Bengal and Philippines in summer and the annual relationships between the heat sources over the Bay of Bengal and Philippines and the precipitation of China in summer are studied emphatically, with the results as follows:(1) The coverage and intensity of atmospheric heat source are the largest and strongest in summer and then turn smaller and weaker in autumn and winter, and in turn begin to become larger and stronger in spring again. There are three strong atmospheric heat source heating centers in Asian monsoon area in summer, of all the heat source centers that over the Bay of Bengal is the strongest, the heat sources over Philippines and the west of India peninsula take the second and third place respectively. (2)There exist obviously interannual and interdecadal changes in the heat sources over the Bay of Bengal and Philippines. (3) When the heat source over the Bay of Bengal is abnormally strong(weak), the Sourthern Asian High extends westward(eastward), and the Western Pacific Subtropical High extends eastward(westward),and the Indian summer monsoon is stronger(weaker), and the eastern Asian tropical summer monsoon is weaker (stronger). The influence of the heat source anomalies over the Bay of Bengal on the Southern Asian High and the south Asian summer monsoon and the Western Pacific Subtropical High is significant, which on the eastern Asian tropical summer monsoon is not very significant. (4) There exists obviously negative correlation between the heat source over the Bay of Bengaland the precipitation of the sourtn of the Yangtze River and the parts of the east of south China in summer, and there exists obviously positive correlation between the heat source over the Bay of Bengal and the precipitation of the area from the sourth west in China to the west of south China. (5) When the heat source over Philippines is abnormally strong,the Southern Asian High becomes two parts. One exists the east area of 100E, the other exists the west area of 80'E,but their locations extend northward. When the heat source over Philippines is abnormally weak, the Southern Asian High becomes only one part and its location extends southward, the Indian summer monsoon is stronger, the eastern Asian tropical summer monsoon is weaker, and the Western Pacific Subtropical High extends southward; The influence of the heat source strong anomalies over Philippines on the east part of the Southern Asian High and the Western Pacific Subtropical High and the east Asian tropical summer monsoon is significant and which on the Indian summer monsoon is not significant; The influence of the heat source weak anomalies over Philippines on the east Asian tropical summer monsoon and the Indian summer monsoon and the Western Pacific Subtropical High and the Southern Asian High is significant. (6) When the heat source over Philippines is abnormally strong, the Western Pacific Subtropical High abnormally extends northward, and the main rainfall area in China is divided two parts including southern rainfall area and northern rainfall area. One is located in south China and south east inshore of China, mainly affected by the eastern Asian tropical summer monsoon;The other is located in Shandong peninsula and Liaodong peninsula and Heilongjiang of China, mainly affected by the eastern Asian subtropical summer monsoon. When the heat source over Philippines is abnormally weak, the Western Pacific Subtropical High abnormally extends southward, and the main rainfall area is located in the south of the Yangtze River,mostly affected by the eastern Asian subtropical summer monsoon.