On the Association between Spring Arctic Sea Ice Concentration and Chinese Summer Rainfall:A Further Study

摘要

In our previous study,a statistical linkage between the spring Arctic sea ice concentration(SIC)and the succeeding Chinese summer rainfall during the period 1968–2005 was identified.This linkage is demonstrated by the leading singular value decomposition(SVD)that accounts for 19%of the co-variance.Both spring SIC and Chinese summer rainfall exhibit a coherent interannual variability and two apparent interdecadal variations that occurred in the late 1970s and the early 1990s.The combined impacts of both spring Arctic SIC and Eurasian snow cover on the summer Eurasian wave train may explain their statistical linkage.In this study,we show that evolution of atmospheric circulation anomalies from spring to summer,to a great extent,may explain the spatial distribution of spring and summer Arctic SIC anomalies,and is dynamically consistent with Chinese summer rainfall anomalies in recent decades.The association between spring Arctic SIC and Chinese summer rainfall on interannual time scales is more important relative to interdecadal time scales.The summer Arctic dipole anomaly may serve as the bridge linking the spring Arctic SIC and Chinese summer rainfall,and their coherent interdecadal variations may reflect the feedback of spring SIC variability on the atmosphere.The summer Arctic dipole anomaly shows a closer relationship with the Chinese summer rainfall relative to the Arctic Oscillation.