The key atmospheric drivers linking regional Arctic amplification with East Asian cold extremes

Across the winters of 1999-2011, both the frequency of extreme cold events in East Asia and the Arctic Amplification showed an upward trend. Here we constructed regional AA index in the winters of 1979-2019, and examine the atmospheric driver that linked with strong AA scenarios and cold extreme in EA. Results show that the local atmospheric blocking are key drivers for regional AA occurrence on the intraseasonal timescale. Ural-Siberia blocking, which is tightly linked to the warming over Barents-Kara Seas (BK), is the primary atmospheric mode when regional AA corresponds with extreme East Asian cold days. However, when there is no warming over BK during the associated cold days in EA, the warming over western hemisphere become prominent, accompanied by the negative phase of the North Atlantic Oscillation (NAO-) and blocking dipole system located at mid-Siberian and East Asian continent. Under this circulation configuration, not only does EA exhibits extremely cooling, but also northeastern North America experiences significant cold anomalies. Furthermore, precursor signals at 2-10 days are found between NAO- and each regional AA event when the days of BK warming are excluded. Our results highlight the importance of atmospheric circulation on linking the warming of different Arctic sectors and cold extremes in the mid-latitude continent, and point out the independent role of NAO- and BKS warming on regional AA.