Distributed ice thickness and glacier volume in southern South America
Distributed ice thickness and glacier volume in southern South America
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DOI：
10.1016/j.gloplacha.2016.09.010
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发表时间：
2016-11-01
影响因子：
3.9
通讯作者：
Glasser, Neil F.
中科院分区：
文献类型：
--
作者：
Carrivick, Jonathan L.;Davies, Bethan J.;Glasser, Neil F.
南美洲的冰川，包括巴塔哥尼亚的冰川，目前是世界上单位冰川面积对海平面上升贡献最大的融水。然而，对相关冰川质量平衡变化背后机制的理解仍然无法量化，部分原因是由于缺乏对冰下地形的了解，阻碍了模式的发展。本研究采用沿冰川中心线的完美塑性模型推导出冰层厚度的一阶估计值，然后在冰川区域内插值这些估计值。该研究首次全面覆盖了南纬41度至55度之间、24个主要冰川区的617个冰川的分布冰厚、床地形和体积。最大模拟冰厚在南巴塔哥尼亚冰原（SPI）为1631 m +/- 179 m，在北巴塔哥尼亚冰原（NPI）为1315 m +/- 145 m，在达尔文科迪勒拉（Cordillera Darwin）为936 m +/- 103 m。NPI的模拟总冰积为1234.6 km(3) +/- 246.8 km(3)， SPI为4326.6 km(3) +/- 865.2 km(3)， Cordillera Darwin的模拟总冰积为151.9 km(3) +/- 30.38 km(3)。总体积为5955 km(3) +/- 1191 km(3)，相当于5458.3 Gt +/- 1091.6 Gt冰和15.08 mm +/- 3.01 mm海平面当量（SLE）。然而，海平面以下的冰总面积为655公里(2)，有282个单独的过深，平均深度为38米，如果充满水到102公里(3)的边缘，总体积为102公里(3)。根据海平面以下冰量和这些过深地区融水的最大潜在储存量调整潜在海平面上升（SLR），最大潜在海平面上升（SLR）为14.71 mm +/- 2.94 mm。我们提供了每个主要河流集水区目前冰量的计算，并讨论了南美洲南部冰川未来可能发生的变化。本研究模拟的冰厚和冰下地形将有助于未来冰动力学和冰川均衡调整的研究，并对预测水资源和冰川灾害具有重要意义。(C) 2016 Elsevier B.V.版权所有
South American glaciers, including those in Patagonia, presently contribute the largest amount of meltwater to sea level rise per unit glacier area in the world. Yet understanding of the mechanisms behind the associated glacier mass balance changes remains unquantified partly because models are hindered by a lack of knowledge of subglacial topography. This study applied a perfect-plasticity model along glacier centre-lines to derive a first order estimate of ice thickness and then interpolated these thickness estimates across glacier areas. This produced the first complete coverage of distributed ice thickness, bed topography and volume for 617 glaciers between 41 degrees S and 55 degrees S and in 24 major glacier regions. Maximum modelled ice thicknesses reach 1631 m +/- 179 m in the South Patagonian Icefield (SPI), 1315 m +/- 145 m in the North Patagonian Icefield (NPI) and 936 m +/- 103 m in Cordillera Darwin. The total modelled volume of ice is 1234.6 km(3) +/- 246.8 km(3) for the NPI, 4326.6 km(3) +/- 865.2 km(3) for the SPI and 151.9 km(3) +/- 30.38 km(3) for Cordillera Darwin. The total volume was modelled to be 5955 km(3) +/- 1191 km(3), which equates to 5458.3 Gt +/- 1091.6 Gt ice and to 15.08 mm +/- 3.01 mm sea level equivalent (SLE). However, a total area of 655 km(2) contains ice below sea level and there are 282 individual overdeepenings with a mean depth of 38 m and a total volume if filled with water to the brim of 102 km(3). Adjusting the potential SLE for the ice volume below sea level and for the maximum potential storage of meltwater in these overdeepenings produces a maximum potential sea level rise (SLR) of 14.71 mm +/- 2.94 mm. We provide a calculation of the present ice volume per major river catchment and we discuss likely changes to southern South America glaciers in the future. The ice thickness and subglacial topography modelled by this study will facilitate future studies of ice dynamics and glacier isostatic adjustment, and will be important for projecting water resources and glacier hazards. (C) 2016 Elsevier B.V. All rights reserved.