Influence and prediction value of Arctic sea ice for spring Eurasian extreme heat events

Abstract

In spring, Eurasia has experienced significant warming, accompanied by frequent extreme heat events. Whether the Arctic sea ice has contributed to the variation of spring Eurasian extreme heat events is still unclear. Here, through conducting statistical analyses of observed and reanalysis data, we demonstrate that the winter sea ice anomalies over the Barents-Kara Seas dominate the leading mode of interannual variation of spring extreme heat events over mid-to-high latitude Eurasia in the recent two decades. With faster decline rate and larger variability, the winter sea ice anomalies over the Barents-Kara Seas significantly enhance the troposphere-stratosphere interactions and further exert influence on the spring atmospheric circulations that favor the formation of Eurasian extreme heat events. Cross-validated hindcasts of the dipole mode index of spring extreme heat events using winter sea ice anomalies over the Barents-Kara Seas yield a correlation skill of 0.71 over 2001–2018, suggesting that nearly 50% of its variance could be predicted one season in advance.