Bamber J L, Tedstone A J, King M D, Howat I M, Enderlin E M, van den Broeke M R, Noel B
School of Geographical Sciences University of Bristol Bristol UK.
Byrd Polar Research Center Ohio State University Columbus OH USA.
J Geophys Res Oceans. 2018 Mar;123(3):1827-1837. doi: 10.1002/2017JC013605. Epub 2018 Mar 5.
The freshwater budget of the Arctic and sub-polar North Atlantic Oceans has been changing due, primarily, to increased river runoff, declining sea ice and enhanced melting of Arctic land ice. Since the mid-1990s this latter component has experienced a pronounced increase. We use a combination of satellite observations of glacier flow speed and regional climate modeling to reconstruct the land ice freshwater flux from the Greenland ice sheet and Arctic glaciers and ice caps for the period 1958-2016. The cumulative freshwater flux anomaly exceeded 6,300 ± 316 km by 2016. This is roughly twice the estimate of a previous analysis that did not include glaciers and ice caps outside of Greenland and which extended only to 2010. From 2010 onward, the total freshwater flux is about 1,300 km/yr, equivalent to 0.04 Sv, which is roughly 40% of the estimated total runoff to the Arctic for the same time period. Not all of this flux will reach areas of deep convection or Arctic and Sub-Arctic seas. We note, however, that the largest freshwater flux anomalies, grouped by ocean basin, are located in Baffin Bay and Davis Strait. The land ice freshwater flux displays a strong seasonal cycle with summer time values typically around five times larger than the annual mean. This will be important for understanding the impact of these fluxes on fjord circulation, stratification, and the biogeochemistry of, and nutrient delivery to, coastal waters.
北极和亚极地北大西洋的淡水收支一直在变化，主要原因是河流径流量增加、海冰减少以及北极陆地冰融化加剧。自20世纪90年代中期以来，后一个因素经历了显著增长。我们结合卫星对冰川流速的观测和区域气候模型，重建了1958 - 2016年期间格陵兰冰盖以及北极冰川和冰帽的陆地冰淡水通量。到2016年，累积淡水通量异常超过了6300±316立方千米。这大约是先前一项分析估计值的两倍，先前的分析未包括格陵兰岛以外的冰川和冰帽，且仅延伸至2010年。从2010年起，总淡水通量约为每年1300立方千米，相当于0.04 Sverdrup，约占同一时期估计流入北极总径流量的40%。并非所有这些通量都会到达深对流区域或北极和亚北极海域。然而，我们注意到，按海盆分类的最大淡水通量异常位于巴芬湾和戴维斯海峡。陆地冰淡水通量呈现出强烈的季节性循环，夏季值通常约为年平均值的五倍。这对于理解这些通量对峡湾环流分层以及沿海水域生物地球化学和营养物质输送的影响至关重要。
