Abstract:By the use of NCEP/NCAR reanalysis dekad sensible heat flux (SHF) dataset from 1979 to1995,the spatial and temporal distribution of SHF over the Asian monsoon region is investigated based on the Rotated Empirical Orthogonal Function(REOF).Results show that the variations of SHF in the Indian Peninsula and the Indochina Peninsula have strong connections to the onset and evolution of Asian monsoon,and these are probably the leading key regions for the monsoon onset.According to the seasonal variation of time coefficient,the accumulations of SHF over the Indian Peninsula and the Indochina Peninsula are probably one of the triggers of east Asian monsoon onset.Moreover,the sudden change of SHF over north of the Indian Peninsula during summer monsoon period probably plays an important role in the evolution of the Indian summer monsoon.In addition,the difference of SHF between the north of the Indian Peninsula and west of the Tibetan Plateau plays an important role in the onset and maintenance of Indian monsoon.However,the difference of SHF between Northeast Asia and Northwest Pacific has influence on the evolution of east Asian summer monsoon only but has no direct connection to winter monsoon.Above all,the forcing of SHF in the north of the Indian Peninsula and the northwest of the Tibetan Plateau plays a leading role in the onset of east Asian monsoon.