Antarctic Topographic Realizations and Geostatistical Modeling Used to Map Subglacial Lakes
Antarctic Topographic Realizations and Geostatistical Modeling Used to Map Subglacial Lakes
复制标题
DOI：
10.1029/2019jf005420
复制
发表时间：
2020-03
期刊：
影响因子：
--
通讯作者：
E. Mackie;Dustin M. Schroeder;J. Caers;Matthew R. Siegfried;C. Scheidt
中科院分区：
文献类型：
--
作者：
E. Mackie;Dustin M. Schroeder;J. Caers;Matthew R. Siegfried;C. Scheidt
南极冰下湖泊在冰盖动力学、生物学、地质学和海洋学方面发挥着重要作用，但很难明确地限制它们的性质和位置。冰下湖泊的位置与热通量、冰面坡度、冰层厚度和河床地形等因素有关，尽管这些关系尚未完全量化。河床地形对于确定水的流动和积聚位置特别重要，但冰盖河床的数字高程模型依赖于插值，并且不切实际地平滑，对冰下湖泊位置和表面积的估计存在偏差。为了解决这个问题，我们使用地质统计学方法来模拟真实粗糙的床地形。我们使用我们模拟的地形来预测整个大陆的冰下湖泊分布使用二项式逻辑回归，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。我们的研究结果表明，地形模型内插没有适当的地质统计学高估冰下湖泊表面积和总湖泊表面积低于先前的预测。我们发现，雷达探测到的湖泊更有可能出现在东南极洲的内部，而高度测量探测到的（活动）湖泊预计将在西南极洲和接地线附近发现。我们观察到，雷达探测到的湖泊与热通量和冰厚度有很高的相关性，而活跃的湖泊与更高的冰速度有关。
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.