Insight on Poleward Moisture and Energy Transport into the Arctic from ERA5

With the new-generation reanalysis product (ERA5), the spatiotemporal characteristics of poleward atmospheric moisture and energy transport over the past four decades (1979-2020) were examined. The main channels of atmospheric transport entering the Arctic in the Northern Hemisphere include the Chukchi Sea at 170 degrees W, Baffin Bay at 50 degrees W, North Atlantic at 0 degrees E, and central Siberia at 90 degrees E. Summer (winter) is characterized by high moisture (energy) transport across 70 degrees N. No clear trend in moisture transport was found, whereas the winter and spring energy transport are declining significantly at a rate of -7.31 x 10(5) W/m/a (99% confidence) and -6.04 x 10(5) W/m/a (95% confidence), respectively. Meanwhile, an increasing trend was found in summer (4.48 x 10(5) W/m/a, 95% confidence) and autumn (3.61 x 10(5) W/m/a, not significant). The relationship between atmospheric moisture and energy transport and different large-scale atmospheric circulation patterns, including the Arctic Oscillation (AO), North Atlantic Oscillation (NAO), and Dipole Anomaly (DA), was explored. Among them, DA was identified as the most favorable pattern in relation to moisture and/or energy intrusion into the Arctic. As a result, the surface air temperature increases are more pronounced over most of the central Arctic under the regulation of DA.