Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA.
Nat Commun. 2013;4:2857. doi: 10.1038/ncomms3857.
Analysis of ICESat-1 data (2003-2008) shows significant surface lowering of Totten Glacier, the glacier discharging the largest volume of ice in East Antarctica, and less change on nearby Moscow University Glacier. After accounting for firn compaction anomalies, the thinning appears to coincide with fast-flowing ice indicating a dynamical origin. Here, to elucidate these observations, we apply high-resolution ice-ocean modelling. Totten Ice Shelf is simulated to have higher, more variable basal melting rates. We link this variability to the volume of cold water, originating in polynyas upon sea ice formation, reaching the sub-ice-shelf cavity. Hence, we propose that the observed increased thinning of Totten Glacier is due to enhanced basal melting caused by a decrease in cold polynya water reaching its cavity. We support this hypothesis with passive microwave data of polynya extent variability. Considering the widespread changes in sea ice conditions, this mechanism could be contributing extensively to ice-shelf instability.
对ICESat-1 数据（2003-2008 年）的分析表明，东南极最大冰量的托滕冰川的表面显著降低，而附近的莫斯科大学冰川变化较小。在考虑到积雪压实异常后，冰层变薄似乎与快速流动的冰一致，表明这是一种动力起源。在这里，为了阐明这些观测结果，我们应用了高分辨率的冰-海建模。托滕冰架的模拟显示出更高、更易变的底部融冰率。我们将这种可变性与冷水量联系起来，这些冷水源源于海冰形成时的冰间湖，到达冰下腔。因此，我们提出，托滕冰川观察到的变薄增加是由于到达其腔的冷冰间湖水量减少导致的基底融化增强所致。我们用冰间湖范围变化的被动微波数据来支持这一假设。考虑到海冰条件的广泛变化，这种机制可能会广泛导致冰架不稳定。
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