The East Asian winter monsoon: re-amplification in the mid-2000s

Abstract

Based on several reanalysis and observational datasets, this study demonstrates that the East Asian winter monsoon (EAWM) recovered from its weak epoch and re-amplified in the mid-2000s. Accordingly, East Asia has experienced more cold winters and significant negative surface air temperature anomalies during the recent strong EAWM epoch spanning the period 2004–2012. The associated cooling was mainly located over inland northern East Asia with a west–east orientation. The cooling generally coincided with negative winter temperature trends in eastern Eurasia in the last two decades, possibly contributing to the observed regional cooling trend when the global mean temperature is still trending up. Enhanced wintertime blocking activity around the Ural mountain region and diminished Arctic sea ice concentration in the previous September are suggested to be the responsible internal atmospheric process and external driver for the recent re-amplification of the EAWM, respectively.