ABSTRACT

Variability of winter sea ice in the Barents Sea and its correlations with external atmospheric forcing have been investigated in a statistical approach based on NSIDC sea ice concentration (SIC) and ECWWF surface air temperature (SAT), wind velocity datasets for the period 1979–2016. The relative SIC, defined as the ratio between sea ice area and extent, indicates that the ice regime is towards lower-concentration conditions. The SIC regression results reveal that the most remarkable ice loss occurs in the northeastern Barents Sea, particularly between 74°-78°N and 42°-67°E. The empirical orthogonal decomposition of SIC has distinguished two principal modes of SIC anomaly. The first principal mode describes 57.7% of the total variance and represents SIC multi-year decreasing trends. The SAT and wind field play a fundamental role in sea ice loss. Additionally, the second principal mode (11.3%) behaves as southeast/central anomaly seesaw, revealing sea ice anomalies are in anti-phase in both corresponding zones. Besides, the wavelet variances of the time coefficient of the two principal components for SIC, SAT and wind velocity anomaly have been analyzed. The most significant peaks for three parameters are with similar variation periods. Accurately, the sea ice is experiencing a decreasing process with uncertain oscillations in some periods due to unsteady synoptic process.

INTRODUCTION

For the past few decades, the Arctic sea ice cover has been decreasing at a sharp pace than before and has become a focus on climate change research. A series of investigations reveal that the most remarkable sea ice loss in summer has occurred in the Pacific sector while in winter the most pronouncing ice plummet is in the Barents Sea and Kara Sea (Johannessen et al., 2004; Su et al., 2011; Yang et al., 2016). Hence, a large number of scholars have concentrated on the dynamical and thermodynamic mechanism of atmosphere-ice-ocean in the Barents Sea.

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