A Study on the Relationship Between Late/Early Onset of The South China Sea Summer Monsoon and Intraseasonal Oscillation

摘要

The National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) Reanalysis data during 1953-1999 are used to analyze the relationship between intraseasonal oscillation intensity and the late/early onset of the summer monsoon in the South China Sea. It is found that the early (late) onset of summer monsoon over the South China Sea is closely related to the strong(weak) activity of atmospheric intraseasonal oscillation in April and May. The composite analysis shows, in early onset years, the intensity index of intraseasonal oscillation over the south of the Indo-china peninsular, the South China Sea, and the southeast of Philippine island is strong, while in late onset years weak. And it is also found that the 30～60 day filtered westerly wind at 850hPa appeared earlier in early onset years than in late onset years.