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Interannual variations in meltwater input to the Southern Ocean from Antarctic ice shelves.
Nature Geoscience ( IF 18.3 ) Pub Date : 2020-08-10 , DOI: 10.1038/s41561-020-0616-z
Susheel Adusumilli 1 , Helen Amanda Fricker 1 , Brooke Medley 2 , Laurie Padman 3 , Matthew R Siegfried 4
Affiliation  

Ocean-driven basal melting of Antarctica’s floating ice shelves accounts for about half of their mass loss in steady state, where gains in ice-shelf mass are balanced by losses. Ice-shelf thickness changes driven by varying basal melt rates modulate mass loss from the grounded ice sheet and its contribution to sea level, and the changing meltwater fluxes influence climate processes in the Southern Ocean. Existing continent-wide melt-rate datasets have no temporal variability, introducing uncertainties in sea level and climate projections. Here, we combine surface height data from satellite radar altimeters with satellite-derived ice velocities and a new model of firn-layer evolution to generate a high-resolution map of time-averaged (2010–2018) basal melt rates and time series (1994–2018) of meltwater fluxes for most ice shelves. Total basal meltwater flux in 1994 (1,090 ± 150 Gt yr–1) was similar to the steady-state value (1,100 ± 60 Gt yr–1), but increased to 1,570 ± 140 Gt yr–1 in 2009, followed by a decline to 1,160 ± 150 Gt yr–1 in 2018. For the four largest ‘cold-water’ ice shelves, we partition meltwater fluxes into deep and shallow sources to reveal distinct signatures of temporal variability, providing insights into climate forcing of basal melting and the impact of this melting on the Southern Ocean.



中文翻译:

从南极冰架输入到南大洋的融水的年际变化。

在稳定状态下,南极浮冰架的海洋驱动基础融化约占其质量损失的一半,在那里,冰架质量的增加与损失的平衡。由于基础融化速率的变化而引起的冰架厚度变化,可调节地面冰原的质量损失及其对海平面的影响,而不断变化的融化水通量会影响南大洋的气候过程。现有的全洲范围的融化速率数据集没有时间变化,因此在海平面和气候预测中引入了不确定性。在这里,我们将卫星雷达高度计的表面高度数据与卫星衍生的冰速以及火层演化的新模型相结合,以生成时间平均(2010-2018)基础融化速率和时间序列(1994年)的高分辨率地图–2018年)大多数冰架的融化水通量。–1)与稳态值(1,100±60 Gt yr –1)类似,但在2009年增加到1,570±140 Gt yr –1,随后在2018年下降到1,160±150 Gt yr –1。我们将四个最大的“冷水”冰架划分为深水源和浅水源,以揭示时间变化的独特特征,从而洞悉基础融化的气候强迫以及这种融化对南大洋的影响。

更新日期:2020-08-10
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