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Antarctic Topographic Realizations and Geostatistical Modeling Used to Map Subglacial Lakes
Journal of Geophysical Research: Earth Surface ( IF 3.9 ) Pub Date : 2020-03-24 , DOI: 10.1029/2019jf005420
E. J. MacKie 1 , D. M. Schroeder 1, 2 , J. Caers 3 , M. R. Siegfried 1, 4 , C. Scheidt 5
Affiliation  

Antarctic subglacial lakes can play an important role in ice sheet dynamics, biology, geology, and oceanography, but it is difficult to definitively constrain their character and locations. Subglacial lake locations are related to factors including heat flux, ice surface slope, ice thickness, and bed topography, though these relationships are not fully quantified. Bed topography is particularly important for determining where water flows and accumulates, but digital elevation models of the ice sheet bed rely on interpolation and are unrealistically smooth, biasing estimates of subglacial lake location and surface area. To address this issue, we use geostatistical methods to simulate realistically rough bed topography. We use our simulated topography to predict subglacial lake distribution across the continent using a binomial logistic regression, which uses physical parameters and known lake locations to calculate the probabilities of lake occurrences. Our results suggest that topography models interpolated without appropriate geostatistics overestimate subglacial lake surface area and that total lake surface area is lower than previously predicted. We find that radar‐detected lakes are more likely to occur in the interior of East Antarctica, while altimetry‐detected (active) lakes are expected to be found in West Antarctica and near the grounding line. We observe that radar‐detected lakes have a high correlation with heat flux and ice thickness, while active lakes are associated with higher ice velocity.

中文翻译:

用于绘制冰河湖底的南极地形实现和地统计学模型

南极冰河湖泊在冰盖动力学,生物学,地质学和海洋学中可以发挥重要作用,但是很难确定地限制其特征和位置。冰川下湖泊的位置与热通量,冰面坡度,冰厚和床形等因素有关,尽管这些关系尚未完全量化。河床地形对于确定水在哪里流动和积聚特别重要,但是冰盖河床的数字高程模型依赖于插值法并且不切实际地平滑,从而使冰湖底位置和表面积的估计值产生偏差。为了解决这个问题,我们使用地统计方法来模拟现实中的粗糙床层地形。我们使用二项式Logistic回归,使用模拟地形来预测整个大陆下的冰河湖分布,它使用物理参数和已知的湖泊位置来计算湖泊发生的概率。我们的结果表明,在没有适当地统计学的情况下进行插值的地形模型高估了冰川下湖的表面积,而总的湖面面积低于先前的预测。我们发现,雷达探测的湖泊更可能出现在南极东部内部,而高程探测的(活动)湖泊则有望在南极西部和接地线附近发现。我们观察到,雷达探测到的湖泊与热通量和冰厚高度相关,而活跃的湖泊与较高的冰速相关。我们的结果表明,在没有适当地统计学的情况下进行插值的地形模型高估了冰川下湖的表面积,而总的湖面面积低于先前的预测。我们发现,雷达探测的湖泊更可能出现在南极东部内部,而高程探测的(活动)湖泊则有望在南极西部和接地线附近发现。我们观察到,雷达探测到的湖泊与热通量和冰厚高度相关,而活跃的湖泊与较高的冰速相关。我们的结果表明,在没有适当地统计学的情况下进行插值的地形模型高估了冰川下湖的表面积,而总的湖面面积低于先前的预测。我们发现,雷达探测的湖泊更可能出现在南极东部内部,而高程探测的(活动)湖泊则有望在南极西部和接地线附近发现。我们观察到,雷达探测到的湖泊与热通量和冰厚高度相关,而活跃的湖泊与较高的冰速相关。预计在南极西部和接地线附近会发现经高程检测的(活动)湖泊。我们观察到,雷达探测到的湖泊与热通量和冰厚高度相关,而活跃的湖泊与较高的冰速相关。预计在南极西部和接地线附近会发现经高程检测的(活动)湖泊。我们观察到,雷达探测到的湖泊与热通量和冰厚高度相关,而活跃的湖泊与较高的冰速相关。
更新日期:2020-03-26
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