Arctic precipitation recycling and hydrologic budget changes in response to sea ice loss

摘要

With a declining sea ice cover, atmospheric moisture and precipitation in the Arctic increases because of the potential for increased evaporation, especially at the regional scale. We quantify the impact of sea ice decline on increasing atmospheric moisture availability from a locally-derived Arctic Ocean source. Between 1950 and 2019, Arctic precipitation recycling has increased from a predominant remote moisture source of 42% to a locally-driven cycle of more than 53% at a rate of 1.3% per decade. While there are almost no significant recycling trends in the summer months in any region, cold-season recycling increases are strongest in the Beaufort-Chukchi, Laptev, Kara, and East Siberian Seas, where sea ice area losses exhibit a strong negative relationship with regional recycling and local evaporation. Arctic-wide sea ice loss accounts for 32% of the in-crease in precipitation recycling, dominated by losses in the Beaufort-Chukchi Seas and the Central Arctic Basin. End-of-century model projections indicate further intensification of Arctic-wide recycling with rates of 60-64% by 2100, but are questionable at the regional scale due to a mismatch of evaporative and advected water vapor fluxes as compared to historical data. Models with realistic sea ice decline indicate that end-of-century net precipitation is higher than other previously reported estimates and will be between 2318 and 2734 km(3) yr(-1).