Geothermal heat flux in the Amundsen Sea sector of West Antarctica: New insights from temperature measurements, depth to the bottom of the magnetic source estimation, and thermal modeling
Geothermal heat flux in the Amundsen Sea sector of West Antarctica: New insights from temperature measurements, depth to the bottom of the magnetic source estimation, and thermal modeling
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DOI：
10.1002/2016gc006755
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发表时间：
2017-07
期刊：
影响因子：
3.7
通讯作者：
R. Dziadek;K. Gohl;Alexander Diehl;N. Kaul
中科院分区：
文献类型：
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作者：
R. Dziadek;K. Gohl;Alexander Diehl;N. Kaul
对松岛冰川和Thwaites冰川的重点研究表明，近几十年来，由于各种原因，如温暖的洋流流入和反向基岩地形，出现了强烈的不稳定迹象，并已被确立为海洋冰盖不稳定假说。地球热通量（GHF）是南极洲一个约束条件较差的参数，并被怀疑影响冰盖的基本条件，即，基底融化和冰下水文学。热力学模型证明了地热通量边界条件对（古）冰盖稳定性的影响。由于西南极洲复杂的构造和岩浆历史，该地区被怀疑表现出强烈的非均匀地热热流变化。我们提出了一种方法，通过不同的方法来研究ASE中的实际热通量范围，讨论直接观测，以及结合各种地球物理研究得出的边界条件的3-D数值模型，包括我们新的磁源底部深度（DBMS）估计。我们在ASE的26个地点进行的现场温度测量是在南极洲西部直接进行GHF观测的三倍多。我们通过数值三维模型证明GHF在空间上从68到110 mW m−2变化。
Focused research on the Pine Island and Thwaites glaciers, which drain the West Antarctic Ice Shelf (WAIS) into the Amundsen Sea Embayment (ASE), revealed strong signs of instability in recent decades that result from variety of reasons, such as inflow of warmer ocean currents and reverse bedrock topography, and has been established as the Marine Ice Sheet Instability hypothesis. Geothermal heat flux (GHF) is a poorly constrained parameter in Antarctica and suspected to affect basal conditions of ice sheets, i.e., basal melting and subglacial hydrology. Thermomechanical models demonstrate the influential boundary condition of geothermal heat flux for (paleo) ice sheet stability. Due to a complex tectonic and magmatic history of West Antarctica, the region is suspected to exhibit strong heterogeneous geothermal heat flux variations. We present an approach to investigate ranges of realistic heat fluxes in the ASE by different methods, discuss direct observations, and 3‐D numerical models that incorporate boundary conditions derived from various geophysical studies, including our new Depth to the Bottom of the Magnetic Source (DBMS) estimates. Our in situ temperature measurements at 26 sites in the ASE more than triples the number of direct GHF observations in West Antarctica. We demonstrate by our numerical 3‐D models that GHF spatially varies from 68 up to 110 mW m−2.