Abstract:The influence of El Niño on the East Asian climate has been studied extensively.Generally,East Asia is warmer than normal in winter when El Niño occurs.During winter 2015/2016,an extreme El Niño event took place-one that was almost the strongest since records began.However,the winter of 2015/2016 was not much warmer than usual.By contrast,East Asia was even colder than normal in January 2016.At the same time,the Arctic experienced extreme warming in winter 2015/2016,which might have had an influence on the winter climate of East Asia.Therefore,in this study,the influences of Arctic warming and the super El Niño during winter 2015/2016 on the East Asian winter climate was investigated using the ENSO index of the Climate Prediction Center of NOAA,along with NCEP/NCAR reanalysis data,for the period 1980-2016.In winter 2015/2016,a super El Niño emerged in the central tropical Pacific.In January 2016,there was a dominant anomalous anticyclone over the western North Pacific and an anomalous cyclone over the Northeast Pacific.Meanwhile,a southerly anomaly was observed over East Asia,which was confined to the area south of 30°N.This meant that there was a particularly evident response of atmospheric circulation in January 2016 to the forcing of ENSO.However,significantly warmer conditions were not observed over East Asia as expected.On the contrary,it was much colder than normal in January.It is interesting to find that the northerly wind in the domain(30-50°N,110-125°E) was stronger in January 2016,which could explain the colder conditions over East Asia.The Rossby wave activity in January 2016 indicates a wave source over the Barents-Kara seas,suggesting that the colder conditions over East Asia might have been related to the Arctic warming that occurred in January 2016.To address this issue,an Arctic temperature index was defined as the area-weighted mean in the Barents-Kara seas(70-80°N,30-70°E).The statistical results from the reanalysis data during 1980-2016 revealed that the warming in the Barents-Kara seas was concurrent with a significant negative temperature anomaly over East Asia.The teleconnection between the Arctic and East Asian temperature was well supported by an obvious southeastward propagation of Rossby waves.Further analysis suggested that the warming in the Barents-Kara seas could induce anomalous ascending motion in situ.The anomalous ascending motion extended eastwards (around 70-90°E) and turned southwards due to the Coriolis force,and finally descended in Siberia(50-70°N,60-100°E).As the air mass accumulated over Siberia,the Siberian high was intensified,leading to anomalous northerly flow in its east,which favored the cold conditions over East Asia.To verify the combined effect of the Arctic warming and El Niño,a statistical prediction model was established via the multivariate linear regression of surface air temperature(SAT) onto the Arctic temperature index and Niño3.4 index.It was found that the hindcasted SAT anomaly over East Asia in January 2016 resembled the observed counterpart well,with a spatial correlation coefficient of 0.71.This implied that the Arctic warming and super El Niño during winter 2015/2016 can to some extent explain the colder than expected conditions in East Asia.