Reduction of residence time of air in the Arctic since the 1980s
Summary
The Arctic has seen dramatic changes in temperature, snow cover, and sea ice in recent decades. Here we use a simple metric, the Arctic residence time of air, that is, the time air spends uninterruptedly north of 70°N, to evaluate how these changes have affected the high-latitude atmospheric circulation in the last 40 years. We find that, on average, near-surface air resides between 7 (summer) and 12 (winter) days in the Arctic. This residence time has decreased almost year-round since the 1980s, especially pronounced in the seasonal transition periods (fall: -1 day; spring: - 1.5 days). In spring, it is likely linked to sea ice loss, a decrease in snow cover, and an increase in temperature. These findings indicate a speed-up of the circulation, effectively making the Arctic less isolated and more prone to influences from mid-latitudes, with consequences for heat, moisture, and pollution import.
