Link Between Autumnal Arctic Sea Ice and Northern Hemisphere Winter Forecast Skill

J C Acosta Navarro,L Batté,P Ortega,E Tourigny,V Sicardi,V Guemas,F Massonnet,P A Bretonnière,V Torralba,F J Doblas‐Reyes,D Smith

doi:10.1029/2019gl086753

Abstract

AbstractDynamical forecast systems have low to moderate skill in continental winter predictions in the extratropics. Here we assess the multimodel predictive skill over Northern Hemisphere high latitudes and midlatitudes using four state‐of‐the‐art forecast systems. Our main goal was to quantify the impact of the Arctic sea ice state during November on the sea level pressure (SLP), surface temperature, and precipitation skill during the following winter. Interannual variability of the November Barents and Kara Sea ice is associated with an important fraction of December to February (DJF) prediction skill in regions of Eurasia. We further show that skill related to sea ice in these regions is accompanied with enhanced skill of DJF SLP in western Russia, established by a sea ice‐atmosphere teleconnection mechanism. The teleconnection is strongest when atmospheric blocking conditions in Scandinavia/western Russia in November reduce a systematic SLP bias that is present in all systems.

Highlights

The Arctic region is undergoing a profound transformation: in the past four decades, the Arctic has warmed twice as fast as the global average (Overland et al, 2015), due to the effect of Arctic amplification (Pithan & Mauritsen, 2014)
Previous studies have found that the sea ice variability in the Barents‐Kara region during autumn exerts an influence on mean winter sea level pressure (SLP) and surface (2‐m) air temperature (SAT) in large areas of northern Eurasia
Our results support this by showing that filtering out the signal explained by detrended Barents and Kara Sea ice (BKSI) anomalies in November significantly degrades skill in predictions of winter (DJF) SLP and precipitation in western Russia and SAT in northern central and East Asia

Summary

Introduction

The Arctic region is undergoing a profound transformation: in the past four decades, the Arctic has warmed twice as fast as the global average (Overland et al, 2015), due to the effect of Arctic amplification (Pithan & Mauritsen, 2014). The quickly evolving climatic conditions have already led to ecological and social changes in the region (Meier et al, 2014; Post et al, 2013). Scientific and nonscientific interest in the remote effects of Arctic warming and sea ice loss on midlatitude weather and climate has quickly grown in the last decade. While there is observationally based evidence that Arctic warming and in particular sea ice loss have led to changes in the climate conditions at the midlatitudes (Mori et al, 2019), the findings are not conclusive (Blackport et al, 2019), and the large natural variability together with the relatively short time covered by observational records may still forbid distinguishing the signal from the noise (Jung et al, 2015)

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