Observed winter Barents Kara Sea ice variations induce prominent sub-decadal variability and a multi-decadal trend in the Warm Arctic Cold Eurasia pattern

Rohit Ghosh (1, 2, 3) , Elisa Manzini (1) , Yongqi Gao (4) , Guillaume Gastineau (5) , Annalisa Cherchi (6, 7) , Claude Frankignoul (5) , Yu-Chiao Liang (8, 9) , Young-Oh Kwon (8) , Lingling Suo (4) , Evangelos Tyrlis (1, 10) , Jennifer Mecking (11) , Tian Tian (12) , Ying Zhang (13) , Daniela Matei (1)

1 MPI-M - Max Planck Institute for Meteorology
2 Department of Meteorology [Reading]
3 Alfred Wegener Institute [Potsdam]
4 NERSC - Nansen Environmental and Remote Sensing Center [Bergen]
5 VARCLIM - Océan et variabilité du climat
6 ISAC - CNR Institute of Atmospheric Sciences and Climate
7 Istituto Nazionale di Geofisica e Vulcanologia
8 WHOI - Woods Hole Oceanographic Institution
9 NTU - National Taiwan University [Taiwan]
10 NKUA - National and Kapodistrian University of Athens
11 NOC - National Oceanography Centre [Southampton]
12 DMI - Danish Meteorological Institute
13 NZC - Nansen-Zhu International Research Center

Abstract The observed winter Barents-Kara Sea (BKS) sea ice concentration (SIC) has shown a close association with the second empirical orthogonal function (EOF) mode of Eurasian winter surface air temperature (SAT) variability, known as Warm Arctic Cold Eurasia (WACE) pattern. However, the potential role of BKS SIC on this WACE pattern of variability and on its long-term trend remains elusive. Here, we show that from 1979 to 2022, the winter BKS SIC and WACE association is most prominent and statistically significant for the variability at the sub-decadal time scale for 5–6 years. We also show the critical role of the multi-decadal trend in the principal component of the WACE mode of variability for explaining the overall Eurasian winter temperature trend over the same period. Furthermore, a large multi-model ensemble of atmosphere-only experiments from 1979 to 2014, with and without the observed Arctic SIC forcing, suggests that the BKS SIC variations induce this observed sub-decadal variability and the multi-decadal trend in the WACE. Additionally, we analyse the model simulated first or the leading EOF mode of Eurasian winter SAT variability, which in observations, closely relates to the Arctic Oscillation (AO). We find a weaker association of this mode to AO and a statistically significant positive trend in our ensemble simulation, opposite to that found in observation. This contrasting nature reflects excessive hemispheric warming in the models, partly contributed by the modelled Arctic Sea ice loss.

Domaines: Planète et Univers [physics]

Rohit Ghosh, Elisa Manzini, Yongqi Gao, Guillaume Gastineau, Annalisa Cherchi, et al.. Observed winter Barents Kara Sea ice variations induce prominent sub-decadal variability and a multi-decadal trend in the Warm Arctic Cold Eurasia pattern. Environmental Research Letters, 2024, 19 (2), pp.024018. ⟨10.1088/1748-9326/ad1c1a⟩. ⟨hal-04498510⟩