Multidecadal seesaw in cold wave frequency between central Eurasia and Greenland and its relation to the Atlantic Multidecadal Oscillation

During the winter, the cold wave activity over the mid-high latitudes has profound impacts on agriculture, economic and human wellbeing. Such extreme weather events have been connected with the East Asia winter monsoon system and significantly influence the climate over the Eurasian continent. However, the multidecadal variabilities and regional interconnections of the cold wave activity across the Northern Hemisphere are lesser-known. In this study, we investigate the multidecadal variations in the cold wave frequency (CWF) and find an inverse relationship between Greenland and central Eurasia. Observational and modeling evidence suggests that the Atlantic Multidecadal Oscillation (AMO) is likely to be the driving force of the multidecadal seesaw in CWF, while the effects of the Arctic sea ice are very limited. The increased sea surface temperature (SST) in association with the AMO warms the subpolar troposphere and weakens the predominant westerlies over mid-high latitudes, resulting in positive geopotential height anomalies over the subpolar region. This further weakens the Icelandic Low and strengthens the Siberian High, which directly induces the warming (cooling) over Greenland (central Eurasia). There is a strong coherence between the mean state of surface air temperature and temperature extremes. The AMO-induced warming/cooling in Greenland/central Eurasia corresponds well with less/more frequent cold wave activities. Our results provide new insight into the multidecadal variability of cold wave activities and suggest that the CWF in the Northern Hemisphere may be interlinked.