Multiple analysis of variation of the East Asian Monsoon during the Holocene

摘要

Abrupt climate shifts at centennial to millennial scale and the periodicities of climate variation are the hot spots in the research of paleoclimates and paleoenvironments. A novel multiple time-scale analysis method. Empirical Mode Decomposition (EMD), is used to diagnose the periodicities and their forcing of East Asian Monsoon variation with a high-resolution numerical-dated Holocene record. The results show that: (1) the variation of East Asian Monsoon can be completely decomposed into eight quasi-period oscillations on various time scales including 13-, 25-, 60-, 111-, 214-, 472-, 974- and 1600-year time scales as well as a trend; moreover, 13-, 25-, 111- and 974-year time scale oscillations are the most prominent periodicities; (2) 11-year and centennial-scale solar activities have not only mixing frequency modulation, but also mixing amplitude modulation on East Asian Monsoon; (3) oscillations at 214-, 472- and 942-year time scale are in wave troughs, which demonstrates that East Asian Monsoon intensity will strengthen in future decades.