East Greenland freshwater runoff to the Greenland-Iceland-Norwegian Seas 1999-2004 and 2071-2100

摘要

In this paper, we quantify the terrestrial flux of freshwater runoff from East Greenland to the Greenland-Iceland-Norwegian (GIN) Seas for the periods 1999-2004 and 2071-2100. Our analysis includes separate calculations of runoff from the Greenland Ice Sheet (GrIS) and the land strip area between the GrIS and the ocean. This study is based on validation and calibration of SnowModel with in situ data from the only two long-term permanent automatic meteorological and hydrometric monitoring catchments in East Greenland: the Mittivakkat Glacier catchment (65 °N) in SE Greenland, and the Zackenberg Glacier catchment (74 °N) in NE Greenland. SnowModel was then used to estimate runoff from all of East Greenland to the ocean. Modelled glacier recession in both catchments for the period 1999-2004 was in accordance with observations, and dominates the annual catchment runoff by 30-90%. Average runoff from Mittivakkat, ～3-7 × 10~(-2) km~3 y~(-1), and Zackenberg, ～21.9 × 10~(-2) km~3 y~(-1), was dominated by the percentage of catchment glacier cover. Modelled East Greenland freshwater input to the North Atlantic Ocean was ～440 km~3 y~(-1) (1999-2004), dominated by contributions of ～40% from the land strip area and ～60% from the GrIS. East Greenland runoff contributes ～10% of the total annual freshwater export from the Arctic Ocean to the Greenland Sea. The future (2071-2100) climate impact assessment based on the Intergovernmental Panel on Climate Change (IPCC) A2 and B2 scenarios indicates an increase of mean annual East Greenland air temperature by 2.7℃ from today's values. For 2071-2100, the mean annual freshwater input to the North Atlantic Ocean is modelled to be ～650 km~3 y~(-1): ～30% from the land strip area and ～70% from the GrIS. This is an increase of approximately ～50% from today's values. The freshwater runoff from the GrIS is more than double from today's values, based largely on increasing air temperature rather than from changes in net precipitation.