Although there is a general consensus about the trends of current climate change, the North Atlantic region deserves special attention, as it is the key region for many climate processes. The aim of this study is to assess the climatic changes in this region for the period 1951–2016, based on the analysis of surface air temperature (SAT) observations from weather stations, and the North Atlantic Oscillation (NAO). Statistical modeling of time series for January, February and March shows a stepwise increase of SAT in Northern Europe in 1987–1989, with the stationarity increasing towards spring. The divided trends of the NAO and SAT indicate a good coherence at the level of climate tendencies. This research reveals the discontinuity of the present-day wintertime warming in Northern Europe, with a warming of about 2 °C after the stepwise jump of the SAT.

The causes of Arctic amplification are widely debated, and a cohesive picture has not been obtained yet. This study has investigated the role of the Atlantic meridional oceanic and atmospheric heat transport into the Arctic in the emergence of Arctic amplification. The integral advective fluxes in the layer of Atlantic waters and in the lower troposphere were considered. The results show a strong coupling between the meridional heat fluxes and regional Arctic amplification in the Eurasian Arctic on the decadal time scales (10–15 years). We argue that the low-frequency variability of Arctic amplification is regulated via the chain of oceanic heat transport — atmospheric heat transport — Arctic amplification. The atmospheric response to the ocean influence occurs with a delay of three years and is attributed to the Bjerknes compensation mechanism. In turn, the atmospheric heat and moisture transport directly affects the magnitude of Arctic amplification, with the latter lagging by one year. Thus, the variability of oceanic heat transport at the southern boundary of the Nordic Seas might be a predictor of the Arctic amplification magnitude over the Eurasian Basin of the Arctic Ocean with a lead time of four years. The results are consistent with the concept of the decadal Arctic climate variability expressed via the Arctic Ocean Oscillation index.

High-latitude atmospheric meridional energy transport plays a fundamental role in the Arctic climate system. However, despite numerous studies, there are no established clear regional features of the atmospheric energy transport components from a large-scale perspective. This study aims at investigating the internal energy and its instantaneous sensible and latent heat transports in the troposphere across the Arctic gate at 70°N using the high-resolution climate reanalysis ERA5. We have done a regional analysis of the time series of heat fluxes across the zonal section and found by decomposing them into empirical orthogonal functions that they have opposing features for the Eastern and Western Hemispheres. In particular, the sensible heat transport dominates in the Western Hemisphere, whereas the latent heat transport dominates in the Eastern Hemisphere. Moreover, we detected the existence of an anti-phase dipole pattern for each of these components in the entire troposphere, which is robust because it continued during the entire studied period 1950–2019. The hemispheric net fluxes indicate that the Arctic gains internal energy mostly due to the latent heat transport.

The causes of Arctic amplification are widely debated, and a cohesive picture has not been obtained yet. This study has investigated the role of the Atlantic meridional oceanic and atmospheric heat transport into the Arctic in the emergence of Arctic amplification. The integral advective fluxes in the layer of Atlantic waters and in the lower troposphere were considered. The results show a strong coupling between the meridional heat fluxes and regional Arctic amplification in the Eurasian Arctic on the decadal time scales (10–15 years). We argue that the low-frequency variability of Arctic amplification is regulated via the chain of oceanic heat transport – atmospheric heat transport – Arctic amplification. The atmospheric response to the ocean influence occurs with a delay of three years and is attributed to the Bjerknes compensation mechanism. In turn, the atmospheric heat and moisture transport directly affects the magnitude of Arctic amplification, with the latter lagging by one year. Thus, the variability of oceanic heat transport at the southern boundary of the Nordic Seas might be a predictor of the Arctic amplification magnitude over the Eurasian Basin of the Artic Ocean with a lead time of four years. The results are consistent with the concept of the decadal Arctic climate variability expressed via the Arctic Ocean Oscillation index.

Poleward transports of oceanic and atmospheric heat play an essential role in the Arctic climate system, and their variations in the future will strongly shape the climate of the Arctic. The main aim of this study is to evaluate the performance of the Coupled Model Intercomparison Project phase 6 (CMIP6) models in the historical experiment in simulating the meridional heat fluxes into the Atlantic sector of the Arctic. The secondary objective is to estimate the meridional oceanic and atmospheric heat fluxes up to the end of the 21st century using the best sub-ensembles of the CMIP6 models. According to our results, the CMIP6 models poorly reproduce the interannual variability of the heat fluxes in their historical simulations, and the multi-model ensemble mean values are systematically lower than the mean values derived from the Ocean ReAnalysis System 4 (ORAS4) and European Centre for Medium-Range Weather Forecasts Reanalysis version 5 (ERA5) reanalyses. Climate projections based on the selected CMIP6 models indicate that the future Arctic climate will be characterized by the significantly increased oceanic heat transport at the entrance to the Atlantic sector of the Arctic relative to the period 1958–2014. In contrast, the atmospheric heat and moisture transport will not have dramatic differences in the projected Arctic climate relative to the period 1958–2014. Based on the results obtained, we emphasize that any interpretation of future climate simulations should be done with caution.