Effects of Quasi-Biennial Oscillation and Summer Monsoon over South China Sea on Interdecadal variability of Summer Precipitation over South China

摘要

There is obvious Quasi-Biennial variability both in summer precipitation over South China (SCSPR) and Summer Monsoon over South China Sea (SCSSM). And interdecadal variations of averaged SCSPR variance in quasi-biennial oscillation play an important role on their interdecadal variations after 1970s. Commonly, the larger variance corresponds on the more precipitation, and vice versa. But there is not clear relation before then. The analyzed results suggest that it is due to interdecadal variation of the quasi-biennial relationship between SCSPR and SCSSM. In the interdecadal phase of 1953-1976, they exhibit weak negative correlation in the quasi-biennial scale, while there is strong positive correlation in the non-biennial scale; in 1977-2000, TBO of SCSPR and SCSSM vary in phase, and they are not clear relation in the non-biennial scale. Further analysis indicate that the catastrophe of general circulation in 1970s make quasi-biennial variation of SCSPR great important in its interannual scale.