Climate change in the Arctic: causes and mechanisms

Abstract

Atmospheric heat and moisture transfers from the North Atlantic make the main contribution to the Arctic warming in winter. The increase in transfer is associated with changes in atmospheric circulation in the Northern Hemisphere under the influence of the sea surface temperature (SST) in low latitudes, where the bulk of the heat influx from the Sun accumulated. The mechanism of influence includes the interaction between the circulation of the ocean and atmosphere, which enhances the oceanic heat influx into the Norwegian and Barents seas, and atmospheric transport to the Arctic. SST rises with participation of orbital-forced increase of the solar insolation. Changes in insolation are small, but their effect is enhanced by feedbacks between temperature, water vapour content and downward long-wave radiation in low latitudes. An increase in water inflow, heat and moisture transfers to the Atlantic Arctic lead to increase in air temperature, water vapour content, downward long-wave radiation, and a reduction of ice thickness growth and its extent in the Barents and Greenland Seas in winter.

Effects of Global Warming on the Poleward Heat Transport by Non-Stationary Large-Scale Atmospheric Eddies, and Feedbacks Affecting the Formation of the Arctic Climate

“…An obvious manifestation of Arctic warming is, among others, a decrease in the sea ice extent during the summer period [17]. As shown in [17,18], the correlation coefficient between changes in the Arctic surface temperature in the summer season and the sea ice in September is about −0.93.…”

“…When studying the essential features of Arctic climate change, one can use additional indicators that characterize the Arctic climate system. For instance, in [9,10], the following nine observational indicators were used to examine the status of the climate and ecosystem at high latitudes: In this regard, it should be emphasized that the Arctic sea ice plays the role of one of the most important indicators of trends in high latitude climate change [11][12][13][14][15][16][17][18][19]. However, the Arctic sea ice extent caused by natural and human-induced factors, in turn, affects the high latitude climate and northern hemispheric climate via feedbacks that, unfortunately, are not completely understood.…”

“…It should be noted that the entire scientific picture of the formation of the Arctic amplification has not yet taken final shape and the causes of this phenomenon are still being discussed within the scientific community. Many recent studies (see [17][18][19][28][29][30][31][32] and references therein) show that the possible causes of Arctic amplification include meridional (equator-to-pole) sensible and latent heat transport in the atmosphere, the decrease in sea ice extent, feedbacks of water vapor, cloud, lapse rate, surface albedo, and Planck feedback. It is clear that many of these physical processes are interdependent.…”

Influence of SST in Low Latitudes on the Arctic Warming and Sea Ice

“…Their impacts intensify the heat accumulation in the ocean; that is, the largest part of the low latitudes area, low albedo of the ocean surface, non-linear feedback between temperature, content of water vapor, and downward longwave radiation. As a result, the positive trend of the insolation in the spring and in the early summer is accompanied by a notable increase of the SST in the autumn (up to 50% of the observed SST trend), air temperature, water vapor content, and downward longwave radiation in the autumn [64]. Finally, in accordance with Figure 8 and the scheme in Figure 9, these changes are evident, such as sea ice reduction and warming in the Arctic in the third year.…”

Rise of Insolation of Low Latitudes Affects Arctic Warming

“…As a result, a slight long-term increase in insolation in spring and early summeris accompanied by a noticeableincrease in sea surface temperature, air temperature, water vapor content anddownward long-wave radiation in autumn, which ultimately affects warming in the Arctic in winter in 2-3years. [19][20][21] Thus, global warming develops with the participation of an increase in insolation of TOA at low latitudes and intensifies in the Arctic under the influence of atmospheric and oceanic transport of heat and moisture.Global climate models simulate ocean warming at low-latitudes insufficiently correct due to underestimation of rise in insolation of the top of the atmosphere and, thereby do not take into consideration one of thefactors of climate warming.…”