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首页> 外文期刊>Journal of Geophysical Research, C. Oceans: JGR >Oceanic controls on the mass balance of Wilkins Ice Shelf, Antarctica
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Oceanic controls on the mass balance of Wilkins Ice Shelf, Antarctica

机译:海洋控制南极威尔金斯冰架的质量平衡

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Several Antarctic Peninsula (AP) ice shelves have lost significant fractions of their volume over the past decades,coincident with rapid regional climate change. Wilkins Ice Shelf (WIS),on the western side of the AP, is the most recent,experiencing a sequence of large calving events in 2008 and 2009.We analyze the mass balance for WIS for the period 1992-2008 and find that the averaged rate of ice-shelf thinning was m a~(-1),driven by a mean basal melt rate of (w_b) = 1.3 ± 0.4 m a~(-1).Interannual variability was large,associated with changes in both surface mass accumulation and (w_h).Basal melt rate declined significantly around 2000 from 1.8 + 0.4 m a~(-1) for 1992-2000 to ~0.75 ± 0.55 m a~(-1) for 2001-2008;the latter value corresponding to approximately steady-state ice-shelf mass.Observations of ocean temperature T obtained during 2007-2009 by instrumented seals reveal a cold,deep halo of Winter Water (WW; T≈-1.6℃) surrounding WIS.The base of the WW in the halo is ~170 m,approximately the mean ice draft for WIS.We hypothesize that the transition in (w_b) in 2000 was caused by a small perturbation (~10-20 m) in the relative depths of the ice base and the bottom of the WW layer in the halo.We conclude that basal melting of thin ice shelves like WIS is very sensitive to upper-ocean and coastal processes that act on shorter time and space scales than those affecting basal melting of thicker West Antarctic ice shelves such as George VI and Pine Island Glacier.
机译:在过去的几十年中,与快速的区域气候变化相吻合,几个南极半岛(AP)的冰架失去了很大一部分体积。 AP西部的威尔金斯冰架(WIS)是最近的一次,在2008年和2009年经历了一系列的大产犊事件。我们分析了1992-2008年WIS的质量平衡,并将其平均值冰架变薄的速率为ma〜(-1),受平均基础融化速率(w_b)= 1.3±0.4 ma〜(-1)的驱动。年际变化较大,与表面质量累积和变化有关。基本熔解速率在2000年左右从1992-2000年的1.8 + 0.4 ma〜(-1)显着下降到2001-2008年的0.75±0.55 ma〜(-1);后者大约对应于稳态冰架质量。2007-2009年通过仪器海豹获得的海洋温度T的观测结果表明,WIS周围有冬季深冷的冬季水(WW;T≈-1.6℃)晕。WW晕的基数约为170。 m,大约是WIS的平均冰吃水量。我们假设2000年(w_b)的转变是由WIS相对深度的较小扰动(〜10-20 m)引起的。我们得出的结论是,像WIS这样的薄冰架的基础融化对上层海洋和沿海过程非常敏感,与影响较厚西部的基础融化的过程相比,它们在较短的时间和空间尺度上起作用南极冰架,例如乔治六世和松岛冰川。

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