In contrast, during November-December 2016 just below 20% of the Barents and Kara Seas were covered with sea-ice (Figure 1). This regional anomalies were the main driver of the lowest pan-Arctic sea-ice extent for those months to-date. Also in 2016, european averaged precipitation was the lowest in 116 years of record for the month of December. A persistent large scale anomalous high sea level pressure pattern located over the continent modified the typical atmospheric flow and was responsible for the low precipitation levels measured throughout the continent.
Large ensemble sensitivity climate model experiments with EC-Earth3.2 in forecast mode indicate that for western Europe, low sea-ice conditions (mostly over the Barents and Kara Seas) partially explain the anomalous atmospheric circulation and its effect on precipitation. However, the main drivers of the extreme low precipitation event were atmospheric (i.e. internal variability) and/or oceanic conditions (i.e. sea surface temperature patterns). The simulations also indicate a similar sea-ice effect on precipitation over northwestern North America during the same month. Coordinated experiments with more models and identical protocol (APPLICATE/PAMIP) will serve to confirm the results and shed light on the existing mechanisms linking sea-ice loss with mid-latitude winter climate.