Advective Heat Transport in Frozen Rock Clefts: Conceptual Model, Laboratory Experiments and Numerical Simulation
Advective Heat Transport in Frozen Rock Clefts: Conceptual Model, Laboratory Experiments and Numerical Simulation
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DOI：
10.1002/ppp.737
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发表时间：
2011-10
影响因子：
5
通讯作者：
A. Hasler;S. Gruber;M. Font;A. Dubois
中科院分区：
文献类型：
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作者：
A. Hasler;S. Gruber;M. Font;A. Dubois
由水渗透到冻土中的不连续面中的平流热量可以迅速增加深层的温度，因为它提供了大气和地下之间的热捷径。在这里，我们开发了一个概念模型，它包含了岩石裂隙中的主要热交换过程。基于该模型的实验室实验和数值模拟结果表明，冰川初始堆积释放的潜热可以迅速升温冰层，并为以后平流感热对裂隙冰的热侵蚀创造条件。如果初始沉积和随后的侵蚀是相同量级的，水的渗透时间和持续时间都会影响冰面的变化。多余的平流热量被裂隙冰的流失和裂隙的径流吸收，因此在地面温度记录中无法直接检测到这种能量。我们的发现表明，即使在寒冷的永久冻土中，如果融水的生产和流动特征发生重大变化，与融化有关的崩塌也是可能的。平流变暖可以迅速影响大型岩体下的破坏平面，因此破坏事件可能与常见的震级反应时间关系有很大不同。版权所有©2011 John Wiley&Sons，Ltd.
Advective heat transported by water percolating into discontinuities in frozen ground can rapidly increase temperatures at depth because it provides a thermal shortcut between the atmosphere and the subsurface. Here, we develop a conceptual model that incorporates the main heat‐exchange processes in a rock cleft. Laboratory experiments and numerical simulations based on the model indicate that latent heat release due to initial ice aggradation can rapidly warm cold bedrock and precondition it for later thermal erosion of cleft ice by advected sensible heat. The timing and duration of water percolation both affect the ice‐level change if initial aggradation and subsequent erosion are of the same order of magnitude. The surplus advected heat is absorbed by cleft ice loss and runoff from the cleft so that this energy is not directly detectable in ground temperature records. Our findings suggest that thawing‐related rockfall is possible even in cold permafrost if meltwater production and flow characteristics change significantly. Advective warming could rapidly affect failure planes beneath large rock masses and failure events could therefore differ greatly from common magnitude reaction‐time relations. Copyright © 2011 John Wiley & Sons, Ltd.