Characteristics of solar activity and its possible relationship with east asian summer monsoon

Abstract

In order to study the variation of solar activity and reveal its relationship with the intensity change of East Asian summer monsoon (EASM), the sunspot time series and EASM intensity index are calculated by using sunspot relative number (SRN) data and sea level barometric data respectively. Then, Morlet wavelet analysis and correlation analysis are used to reveal the interdecadal characteristics of solar activity and EASM changes with their relationship. The results show that after the 1940s, the SRN and the fluctuation amplitude of the EASM index increased gradually, and reached the maximum from the 1950s to the mid-1960s. The influence of solar activity on the interdecadal variations of EASM is significant, with the same 40-year and 11-year cycles. The correlation between them is relatively good on the centennial scale, showing a "- + -" correlation with time change.