Decadal topographic change in the McMurdo Dry Valleys of Antarctica: Thermokarst subsidence, glacier thinning, and transfer of water storage from the cryosphere to the hydrosphere
Decadal topographic change in the McMurdo Dry Valleys of Antarctica: Thermokarst subsidence, glacier thinning, and transfer of water storage from the cryosphere to the hydrosphere
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南极洲麦克默多干谷的年代际地形变化：热岩溶沉降、冰川变薄以及水储存从冰冻圈转移到水圈
DOI：
10.1016/j.geomorph.2018.09.012
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发表时间：
2018
期刊：
影响因子：
3.9
通讯作者：
Van Horn, D.J.
中科院分区：
文献类型：
--
作者：
Levy, J.S.;Fountain, A.G.;Obryk, M.K.;Telling, J.;Glennie, C.;Pettersson, R.;Gooseff, M.;Van Horn, D.J.
最近对南极洲麦克默多干谷（MDV）冰川、河流和土壤表面的局部尺度观测记录了与地冰融化相关的快速冰损失、冰川变薄和地表沉降的证据。为了评估MDV中十年尺度景观变化的范围，幅度和位置，我们收集了2014-2015年的机载激光雷达高程数据，并将这些数据与2001-2002年的机载激光雷达活动进行了比较。这种区域评估的海拔变化跨越了最近的加速变暖和融化观察到的长期气象和生态系统响应实验，使我们能够评估MDV表面变暖和潜在的解冻反馈的反应。我们发现，热岩溶沉降的位置与过量的地下冰的存在和接近地表或浅层地下（活动层）水密切相关。沉降发生在各种土壤类型和地貌上，在排水不畅的低洼、低坡地区，也在陡峭的谷壁高处。冰川变薄是普遍存在的，并与细尺度粗糙度的增长有关。在MDV的大多数封闭流域湖泊中，所有小气候区的池塘水位都在上升。这些观测结果突出了MDV中日照驱动融化的持续重要性。区域融化模式是一致的水存储从当地的冰冻圈（冰川，永久冻土）到水圈（封闭的盆地湖泊和池塘以及罗斯海）的整体过渡。我们解释这种区域融化模式，以反映过渡到北极和阿尔卑斯式，水文介导的永久冻土和冰川融化。
Recent local-scale observations of glaciers, streams, and soil surfaces in the McMurdo Dry Valleys of Antarctica (MDV) have documented evidence for rapid ice loss, glacial thinning, and ground surface subsidence associated with melting of ground ice. To evaluate the extent, magnitude, and location of decadal-scale landscape change in the MDV, we collected airborne lidar elevation data in 2014–2015 and compared these data to a 2001–2002 airborne lidar campaign. This regional assessment of elevation change spans the recent acceleration of warming and melting observed by long-term meteorological and ecosystem response experiments, allowing us to assess the response of MDV surfaces to warming and potential thawing feedbacks. We find that locations of thermokarst subsidence are strongly associated with the presence of excess ground ice and with proximity to surface or shallow subsurface (active layer) water. Subsidence occurs across soil types and landforms, in low-lying, low-slope areas with impeded drainage and also high on steep valley walls. Glacier thinning is widespread and is associated with the growth of fine-scale roughness. Pond levels are rising in most closed-basin lakes in the MDV, across all microclimate zones. These observations highlight the continued importance of insolation-driven melting in the MDV. The regional melt pattern is consistent with an overall transition of water storage from the local cryosphere (glaciers, permafrost) to the hydrosphere (closed basin lakes and ponds as well as the Ross Sea). We interpret this regional melting pattern to reflect a transition to Arctic and alpine-style, hydrologically mediated permafrost and glacial melt.
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作者：
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DOI：
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发表时间：
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作者：
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