Ocean access to a cavity beneath Totten Glacier in East Antarctica
Ocean access to a cavity beneath Totten Glacier in East Antarctica
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DOI：
10.1038/ngeo2388
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发表时间：
2015-04-01
影响因子：
18.3
通讯作者：
Siegert, M. J.
中科院分区：
文献类型：
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作者：
Greenbaum, J. S.;Blankenship, D. D.;Siegert, M. J.
托滕冰川是极光冰下盆地的主要出口，是东南极洲变薄速度最快的(1，2)。变薄可能是由海洋过程(3)增强的基底熔融推动的，受Polynya活动(4，5)的调制。夏季和冬季，在附近大陆架400至500米的南极表层冷水(7，8)下观察到了与南极西部冰川退缩有关的暖修正环极深水(6)。在这里，我们根据重力(9)和磁学(10)数据以及冰层厚度测量(11)推导出该区域海底的水深测量。我们确定了400到500米深度以下的冰架洞穴的入口，如果流入的垂直结构与附近的观测结果相似，这些入口可能会允许暖水侵入。雷达探测揭示了一个以前不为人知的内陆海槽，它连接着主要的冰架洞穴和海洋。如果变薄的趋势继续下去，海槽上方更大的水体可能会允许更多的温水进入洞穴，这最终可能导致托滕冰川和流入雷诺兹海槽的类似深度的冰川之间的低洼地区不稳定。我们估计，至少3.5米的海平面可能会流经托滕冰川，因此这一地区的沿海过程可能会对全球产生影响。
Totten Glacier, the primary outlet of the Aurora Subglacial Basin, has the largest thinning rate in East Antarctica(1,2). Thinning may be driven by enhanced basal melting due to ocean processes(3), modulated by polynya activity(4,5). Warm modified Circumpolar Deep Water, which has been linked to glacier retreat in West Antarctica(6), has been observed in summer and winter on the nearby continental shelf beneath 400 to 500 m of cool Antarctic Surface Water(7,8). Here we derive the bathymetry of the sea floor in the region from gravity(9) and magnetics(10) data as well as ice-thickness measurements(11). We identify entrances to the ice-shelf cavity below depths of 400 to 500 m that could allow intrusions of warm water if the vertical structure of inflow is similar to nearby observations. Radar sounding reveals a previously unknown inland trough that connects the main ice-shelf cavity to the ocean. If thinning trends continue, a larger water body over the trough could potentially allow more warm water into the cavity, which may, eventually, lead to destabilization of the low-lying region between Totten Glacier and the similarly deep glacier flowing into the Reynolds Trough. We estimate that at least 3.5 m of eustatic sea level potential drains through Totten Glacier, so coastal processes in this area could have global consequences.