Supraglacial weathering crust dynamics inferred from cryoconite hole hydrology
Supraglacial weathering crust dynamics inferred from cryoconite hole hydrology
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DOI：
10.1002/hyp.10602
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发表时间：
2016-01-30
影响因子：
3.2
通讯作者：
Irvine-Fynn, Tristram D. L.
中科院分区：
文献类型：
--
作者：
Cook, Joseph Mitchell;Hodson, Andy J.;Irvine-Fynn, Tristram D. L.
在澳大利亚布罗格布赖恩(斯瓦尔巴群岛)上，以高分辨率在3周的时间里监测到了低温球果洞穴中的水位。这些数据与融化和能量平衡模型相结合，为冰川近地表水文学的演变提供了洞察力，并证实了被称为“风化壳”的近地表多孔冰的水文学是动态的，类似于浅层含水层。在风化壳中，熔体的辐射强迫与排水效率呈正相关。这很可能是由于表面能量平衡中辐射通量和湍流通量的变化导致间质孔隙空间的昼夜收缩和扩张，偶尔会导致“突然排水事件”。还观察到低温球洞中的水位呈线性下降，这归因于测量期间近地表冰孔隙率的累积增加。颗粒物质和微生物在多孔风化壳中的传输取决于风化壳的水力学和颗粒大小。因此，冷锥石孔提供了风化地壳的水文动力学的指示，并为冰川表面的低温锥石提供了长期的储存场所。这项研究强调了风化壳作为冰川生态系统和冰川化地区的水文、生态和生物地球化学的重要组成部分的重要性，并证明了冰川表面的天然压力计--低温孔洞的用途。版权所有(C)2015 John Wiley&Sons，Ltd.
Water levels in cryoconite holes were monitored at high resolution over a 3-week period on Austre Broggerbreen (Svalbard). These data were combined with melt and energy balance modelling, providing insights into the evolution of the glacier's near-surface hydrology and confirming that the hydrology of the near-surface, porous ice known as the 'weathering crust' is dynamic and analogous to a shallow-perched aquifer. A positive correlation between radiative forcing of melt and drainage efficiency was found within the weathering crust. This likely resulted from diurnal contraction and dilation of interstitial pore spaces driven by variations in radiative and turbulent fluxes in the surface energy balance, occasionally causing 'sudden drainage events'. A linear decrease in water levels in cryoconite holes was also observed and attributed to cumulative increases in near-surface ice porosity over the measurement period. The transport of particulate matter and microbes between cryoconite holes through the porous weathering crust is shown to be dependent upon weathering crust hydraulics and particle size. Cryoconite holes therefore yield an indication of the hydrological dynamics of the weathering crust and provide long-term storage loci for cryoconite at the glacier surface. This study highlights the importance of the weathering crust as a crucial component of the hydrology, ecology and biogeochemistry of the glacier ecosystem and glacierized regions and demonstrates the utility of cryoconite holes as natural piezometers on glacier surfaces. Copyright (C) 2015 John Wiley & Sons, Ltd.