Arctic sea ice decline and continental cold anomalies: Upstream and downstream effects of Greenland blocking

The influence of Greenland blocking on continental cold anomalies in the Northern Hemisphere is examined. It is found that westward moving Greenland blocking (WGB) events in the recent decade are more strongly related to the sea ice decline over the Baffin Bay, Davis Strait, and Labrador Sea (BDL), while the quasi‐stationary Greenland blocking (QGB) events are more strongly related to the negative phase of the North Atlantic Oscillation. The frequency of WGB events is significantly increased owing to reduced mid‐high‐latitude westerly winds in the North Atlantic and its upstream region because of intensified Arctic warming related to the large BDL sea ice decline. It is further revealed that North American low temperatures are more sensitive to the WGB, while European low temperatures are more sensitive to the QGB. For the WGB, an intense cold anomaly is seen over the eastern North America. But for the QGB, strong cold anomalies appear over the North Europe and eastern Asia. Thus, it is concluded that more winter cold air outbreaks should occur over the eastern North America, if large BDL sea ice decline continues in the recent decade.