Regional Arctic sea ice variations as predictor for winter climate conditions

Torben Koenigk,Mihaela Caian,Semjon Schimanke,Grigory Nikulin

doi:10.1007/s00382-015-2586-1

Torben Koenigk, Mihaela Caian + Show 2 more

Open Access

https://doi.org/10.1007/s00382-015-2586-1

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Abstract

Seasonal prediction skill of winter mid and high northern latitudes climate from sea ice variations in eight different Arctic regions is analyzed using detrended ERA-interim data and satellite sea ice data for the period 1980–2013. We find significant correlations between ice areas in both September and November and winter sea level pressure, air temperature and precipitation. The prediction skill is improved when using November sea ice conditions as predictor compared to September. This is particularly true for predicting winter NAO-like patterns and blocking situations in the Euro-Atlantic area. We find that sea ice variations in Barents Sea seem to be most important for the sign of the following winter NAO—negative after low ice—but amplitude and extension of the patterns are modulated by Greenland and Labrador Seas ice areas. November ice variability in the Greenland Sea provides the best prediction skill for central and western European temperature and ice variations in the Laptev/East Siberian Seas have the largest impact on the blocking number in the Euro-Atlantic region. Over North America, prediction skill is largest using September ice areas from the Pacific Arctic sector as predictor. Composite analyses of high and low regional autumn ice conditions reveal that the atmospheric response is not entirely linear suggesting changing predictive skill dependent on sign and amplitude of the anomaly. The results confirm the importance of realistic sea ice initial conditions for seasonal forecasts. However, correlations do seldom exceed 0.6 indicating that Arctic sea ice variations can only explain a part of winter climate variations in northern mid and high latitudes.

Highlights

Observations of the last decades indicate an ongoing climate change in the Arctic
Most of these studies found that a reduction or negative anomaly in late summer sea ice extent leads to winter atmospheric circulation anomalies resembling the negative phase of the North Atlantic Oscillation (NAO) and to cold mid-latitude winters
The September northern hemispheric (NH) ice area is highly correlated with ice area variations in the Laptev/East Siberian Seas (LAPSIB), Chukchi/Bering Seas (CHUBER) and Beaufort Sea (BEAU) (Table 2, upper right)

Summary

Introduction

Observations of the last decades indicate an ongoing climate change in the Arctic. The observed warming of near surface temperature in the Arctic is twice or more the rate of the global mean warming in the last decades (Stocker et al 2013; Richter-Menge and Jeffries 2011). Recent studies based on both observational based data sets and model simulations indicated a connection between variations of late summer Arctic sea ice extent and winter mid-latitude conditions (Petoukhov and Semenov 2010; Francis et al 2009; Yang and Christensen 2012; Overland and Wang 2010; Hopsch et al 2012; Garcia-Serrano and Frankkignoul 2014). Most of these studies found that a reduction or negative anomaly in late summer sea ice extent leads to winter atmospheric circulation anomalies resembling the negative phase of the North Atlantic Oscillation (NAO) and to cold mid-latitude winters. Such ice distributions might lead to an amplification of the atmospheric response or could reduce the signal but in any case make the interpretation of the signal difficult

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