Modeling 5 years of subglacial lake activity in the MacAyeal Ice Stream (Antarctica) catchment through assimilation of ICESat laser altimetry
Modeling 5 years of subglacial lake activity in the MacAyeal Ice Stream (Antarctica) catchment through assimilation of ICESat laser altimetry
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通过 ICESat 激光测高同化，对 MacAyeal 冰流（南极洲）流域 5 年的冰下湖泊活动进行建模
DOI：
10.3189/002214311798843421
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发表时间：
2011
影响因子：
3.4
通讯作者：
D. Young
中科院分区：
文献类型：
--
作者：
S. Carter;H. Fricker;D. Blankenship;Jesse Johnson;W. Lipscomb;S. Price;D. Young
摘要南极快速冰流下的冰下湖泊在每年的时间尺度上经历了∼1千米的体积变化。以MacAyeal Ice Stream(Macis)湖泊系统为研究对象，通过同化ICESat激光测高估算的湖泊体积变化，建立了冰下水分布对湖泊流量事件响应的简单模型。我们构建了一个稳态水传输模型，在该模型中，已知的冰下湖泊被视为汇或源，取决于ICESat导出的充填率或排泄率。模拟的5个大型冰下湖泊的体积变化率表明，如果考虑所有上游湖泊的动态，则模拟的体积变化率与观测的充盈速率一致。然而，最北端湖泊的可变填充率表明，上游存在一个类似大小的未被探测到的湖泊。总体而言，我们表明，对于这种快速流动的冰流，大多数冰下湖泊90%的水来自整个集水区内遥远的分布式来源，我们证实，水从净基面融化的区域输送到净基面冻结的区域。我们的研究提供了一种验证南极冰下水模型的基于地球物理的方法，并为在有足够数据可用的大规模冰盖模型中对冰下湖泊排放事件进行参数化提供了一种潜在的方法。
Abstract Subglacial lakes beneath Antarctica’s fast-moving ice streams are known to undergo ∼1 km3 volume changes on annual timescales. Focusing on the MacAyeal Ice Stream (MacIS) lake system, we create a simple model for the response of subglacial water distribution to lake discharge events through assimilation of lake volume changes estimated from Ice, Cloud and land Elevation Satellite (ICESat) laser altimetry. We construct a steady-state water transport model in which known subglacial lakes are treated as either sinks or sources depending on the ICESat-derived filling or draining rates. The modeled volume change rates of five large subglacial lakes in the downstream portion of MacIS are shown to be consistent with observed filling rates if the dynamics of all upstream lakes are considered. However, the variable filling rate of the northernmost lake suggests the presence of an undetected lake of similar size upstream. Overall, we show that, for this fast-flowing ice stream, most subglacial lakes receive >90% of their water from distant distributed sources throughout the catchment, and we confirm that water is transported from regions of net basal melt to regions of net basal freezing. Our study provides a geophysically based means of validating subglacial water models in Antarctica and is a potential way to parameterize subglacial lake discharge events in large-scale ice-sheet models where adequate data are available.
影响因子：
18.3
作者：
Rignot, Eric;Bamber, Jonathan L.;Van Meijgaard, Erik
通讯作者：
Van Meijgaard, Erik