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Abstract:
The Arctic has experienced dramatic climate changes over recent decades, in which Arctic amplification is the most prominent characteristic with broad influences on climate variability over mid-/low-latitude regions. Previous studies have indicated that Arctic surface warming is simultaneously accompanied by frequent cold winters over Northern Hemisphere mid-latitude continents, forming a "warm Arctic-cold continent" pattern. In addition, other studies suggest a lead-lag seesaw pattern of extreme temperature events with a cold spell over East Asia followed by a warm spell in North America. In this study, we reveal a dipole-like surface air temperature pattern between the Eurasian and North American continents in boreal winter induced by the Arctic sea-ice variability. This surface temperature dipole pattern works on both interannual and decadal time scales. Statistical analyses and atmospheric model experiments demonstrate that the sea-ice retreat over the Barents-Kara Seas can trigger a wavenumber one atmospheric circulation pattern over Northern Hemisphere high-latitudes, with a high-pressure center over north Siberia and a low-pressure center over high-latitude North America. The atmospheric circulation adjustment contributes to a cooling over central Eurasia and a warming in North America through thermal advection. Our finding helps improve the understanding of the relationship between Arctic sea ice and climate variability over Northern Hemisphere mid-latitude continents and has important implications on future climate prediction.
