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首页> 外文学位 >Insights into Processes Affecting Greenland Ice Sheet Dynamics in a Changing Climate: Firn Permeability, Interior Thermal State, Subglacial Hydrology, and Heat Transfer Coefficients
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Insights into Processes Affecting Greenland Ice Sheet Dynamics in a Changing Climate: Firn Permeability, Interior Thermal State, Subglacial Hydrology, and Heat Transfer Coefficients

机译：洞察影响气候变化的格陵兰冰盖动力学的过程：渗透率，内部热态，冰川下水文学和传热系数

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摘要

Accurate projections of future sea level rise require detailed modeling of the relevant processes affecting glacier and ice sheet dynamics. Although sophisticated high-resolution ice sheet models have been developed in recent years, some processes are still not well understood. Through a combination of field experiments, numerical modeling, and theoretical analyses, this research explores several processes affecting dynamics of the Greenland ice sheet, particularly in a changing climate as melt increases further inland: a) A novel, low-cost in-situ method of inferring firn permeability is presented, which is especially useful in regions of the ice sheet experiencing increased melt and refrozen solid ice layers in the firn. b) Thermo-mechanically coupled flow line modeling of the Greenland ice sheet interior reveals insights about the distribution of temperate ice and sensitivity to different modeling parameters. c) A subglacial hydrology model is introduced (SHAKTI: Subglacial Hydrology and Kinetic, Transient Interactions) that allows for the coexistence of laminar and turbulent flow regimes and flexible geometry configurations that include both sheetlike and channelized drainage systems, while including melt from viscous dissipation. Application of the SHAKTI model to marine-terminating Store Glacier in west Greenland suggests a channelized system develops near the terminus with high meltwater input and collapses to a sheetlike system with low input, with some residual channel structure extending inland from the front. d) Heat transfer coefficients are obtained through modeling of internal viscous and turbulent dissipation (appropriate for subglacial and englacial hydrology) compared to the case of heated walls (the classical experimental case upon which most heat transfer coefficients are based). A difference of about a factor of two is found between the heat transfer coefficients for heated walls and the internal dissipation case.
机译：对未来海平面上升的准确预测需要对影响冰川和冰盖动力学的相关过程进行详细建模。尽管近年来已开发出复杂的高分辨率冰盖模型，但某些过程仍未得到很好的理解。通过野外实验，数值模拟和理论分析的结合，本研究探索了影响格陵兰冰盖动力学的多个过程，尤其是在融化进一步增加内陆气候变化的情况下：a）一种新颖，低成本的原位方法提出了推导熔炉渗透率的方法，其在冰盖的区域中尤其有用，该区域经历了熔炉中融化和固态冰层的增加。 b）格陵兰冰原内部的热力耦合流线建模揭示了有关温带冰的分布以及对不同建模参数的敏感性的见解。 c）引入了冰川下水文模型（SHAKTI：冰川下水文和动力学，瞬态相互作用），该模型允许层流和湍流状态以及灵活的几何构造并存，包括片状和通道化排水系统，同时包括粘性耗散引起的融化。将SHAKTI模型应用到格陵兰西部的海洋终结的Store Glacier上，表明通道化系统在具有高熔体水输入量的终点附近发展，并崩溃为低输入量的片状系统，并且一些残余的通道结构从前部向内陆延伸。 d）与加热壁的情况（大多数传热系数所基于的经典实验情况）相比，通过对内部粘性和湍流消散（适用于冰川下和冰川水文学）进行建模，可获得传热系数。在加热壁的传热系数与内部散热情况之间发现了大约两倍的差异。

著录项

  • 作者

    Sommers, A. N.;

  • 作者单位

    University of Colorado at Boulder.;

  • 授予单位 University of Colorado at Boulder.;
  • 学科 Civil engineering.;Hydrologic sciences.
  • 学位 Ph.D.
  • 年度 2018
  • 页码 196 p.
  • 总页数 196
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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