An inventory of supraglacial lakes and channels across the West Antarctic Ice Sheet
An inventory of supraglacial lakes and channels across the West Antarctic Ice Sheet
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DOI：
10.5194/essd-2021-257
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发表时间：
2021-08
影响因子：
11.4
通讯作者：
Diarmuid Corr;A. Leeson;M. McMillan;Ce Zhang;T. Barnes
中科院分区：
文献类型：
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作者：
Diarmuid Corr;A. Leeson;M. McMillan;Ce Zhang;T. Barnes
摘要。量化冰川上水文（即湖泊和溪流）的范围和分布，对于了解南极冰盖的物质平衡及其对全球海平面上升的影响非常重要。通过水力压裂和相关的融水向床的输送，冰面上存在的融水有可能影响冰架的稳定性和接地冰的流动。在这项研究中，我们对2017年1月由Sentinel-2和Landsat-8卫星获得的bbb2000图像应用半自动双ndwi（归一化差水指数）方法，系统地绘制了南极洲西部所有可观测的冰川上湖泊和溪流。我们使用K-Means聚类方法将水划分为湖泊和溪流，这对于理解水文系统的动态和互联性非常重要。与三个南极试验点手动划分的参考数据集相比，我们的方法分别达到了Sentinel-2和Landsat-8采集的灵敏度（85.3%和77.6%）、特异性（99.1%和99.7%）和准确性（98.7%和98.3%）的平均值。在南极西部冰原（WAIS）和南极半岛（AP）共发现10478个冰上地貌（10223个湖泊和255个河道），总面积为119.4 km2 （114.7 km2湖泊和4.7 km2河道）。27.3%的特征面积位于接地冰上，17.8%的特征面积由跨越接地线的湖泊组成，54.9%的特征面积位于浮冰架上。由于最近卫星数据供应的扩大，诸如此类的新大陆规模的清单成为可能，这些清单是第一次为WAIS和AP编制的。这些清单为今后的研究提供了一个基线，并为监测在变暖的世界中南极地表水文的发展提供了一个基准，从而提高了我们预测未来冰架崩塌的能力。该数据集可在https://doi.org/10.5281/zenodo.5109856上获得（Corr et al., 2021）。
Abstract. Quantifying the extent and distribution of supraglacial hydrology, i.e. lakes and streams, is important for understanding the mass balance of the Antarctic ice sheet, and its consequent contribution to global sea level rise. The existence of meltwater on the ice surface has the potential to affect ice shelf stability and grounded ice flow, through hydrofracturing and the associated delivery of meltwater to the bed. In this study, we systematically map all observable supraglacial lakes and streams in West Antarctica, by applying a semi-automated Dual-NDWI (Normalised Difference Water Index) approach to > 2000 images acquired by the Sentinel-2 and Landsat-8 satellites during January 2017. We use a K-Means clustering method to partition water into lakes and streams, which is important for understanding the dynamics and inter-connectivity of the hydrological system. When compared to a manually-delineated reference dataset on three Antarctic test sites, our approach achieves average values for sensitivity (85.3 % and 77.6 %), specificity (99.1 % and 99.7 %) and accuracy (98.7 % and 98.3 %) for Sentinel-2 and Landsat-8 acquisitions, respectively. In total, we identified 10,478 supraglacial features (10,223 lakes and 255 channels) on the West Antarctic Ice Sheet (WAIS) and Antarctic Peninsula (AP), with a combined area of 119.4 km2 (114.7 km2 lakes, 4.7 km2 channels). 27.3 % of feature area was found on grounded ice, 17.8 % of feature area comprised lakes which crossed the grounding line, while 54.9 % of feature area was found on floating ice shelves. New continental-scale inventories such as these, the first produced for WAIS and AP, are made possible by the recent expansion in satellite data provision. The inventories provide a baseline for future studies and a benchmark to monitor the development of Antarctica’s surface hydrology in a warming world, and thus enhance our capability to predict the collapse of ice shelves in the future. The dataset is available at https://doi.org/10.5281/zenodo.5109856 (Corr et al., 2021).