Observed and Simulated Linkage between Ural Blocking and East Asian Winter Climate

Abstract:

Winter Ural blocking (UB) is a potential trigger of cold extremes in the East Asia. The interannual and decadal variations of the UB frequency are closely related to the winter-mean temperature and the cold extreme frequency in East Asia. In the past decade, its increasing frequency was a possible cause of some unprecedented cold events in the region, such as the persistent snowstorm and icy rains in southern China in early 2008. An accurate projection of the UB frequency is one of the crucial factors for evaluating the East Asian winter climate.

We will first present the observational linkage between UB and the East Asian winter climate, where the possible role of large-scale teleconnections (e.g., North Atlantic Oscillation, ENSO) is highlighted. Then, we will assess the ability of 25 CMIP5 GCMs to simulate the UB‒East Asian winter climate linkage. Afterward, we will focus on the future changes of UB in RCP4.5 and 8.5 scenarios and their implications on East Asian winter circulation. Our results show that, in the late 21^st century, the year-to-year variation of the UB frequency form a stronger linkage with the large-scale circulation over the Kara and Laptev Seas. Meanwhile, UB likely exerts a stronger impact on East Asia on synoptic and seasonal timescales.