Below-surface ice melt on the coastal Antarctic ice sheet
Below-surface ice melt on the coastal Antarctic ice sheet
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DOI：
10.3189/s0022143000001775
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发表时间：
1999-06
影响因子：
3.4
通讯作者：
G. Liston;J. Winther;O. Bruland;H. Elvehøy;K. Sand
中科院分区：
文献类型：
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作者：
G. Liston;J. Winther;O. Bruland;H. Elvehøy;K. Sand
摘要 在南极洲 Dronning Maud 地的 Jutulgryta 地区，观测到冰盖地下融化。融化发生在夏季，在空气和表面温度低于冰点的条件下，蓝冰地区发生融化。邻近的积雪地区具有相同的气象和气候条件，地下融化很少或没有。为了帮助解释和理解在蓝冰和雪覆盖区域观察到的融化速率差异，开发了一个基于物理的耦合大气、辐射、雪和蓝冰系统的数值模型。该模型包括传热方程，其中包括光谱相关的太阳辐射源项。辐射对雪和蓝冰的渗透取决于太阳辐射光谱、表面反照率以及雪和蓝冰的颗粒尺寸和密度。此外，该模型使用完整的表面能量平衡来定义表面边界条件。它在整个年度周期中运行，模拟整个夏季和冬季的温度分布以及融化和冻结量。该模型使用 1996-97 年挪威南极考察 (NARE) 期间收集的实地观测数据进行驱动和验证。模拟表明，观察到的地下雪和蓝冰融化之间的差异很大程度上可以通过两种介质之间的反照率、晶粒尺寸和密度差异引起的辐射和传热相互作用来解释。
Abstract In the Jutulgryta area of Dronning Maud Land, Antarctica, subsurface melting of the ice sheet has been observed. The melting takes place during the summer months in blue-ice areas under conditions of below-freezing air and surface temperatures. Adjacent snow-covered regions, having the same meteorological and climatic conditions, experience little or no subsurface melting. To help explain and understand the observed melt-rate differences in the blue-ice and snow-covered areas, a physically based numerical model of the coupled atmosphere, radiation, snow and blue-ice system has been developed. The model comprises a heat-transfer equation which includes a spectrally dependent solar-radiation source term. The penetration of radiation into the snow and blue ice depends on the solar-radiation spectrum, the surface albedo and the snow and blue-ice grain-sizes and densities. In addition, the model uses a complete surface energy balance to define the surface boundary conditions. It is run over the full annual cycle, simulating temperature profiles and melting and freezing quantities throughout the summer and winter seasons. The model is driven and validated using field observations collected during the Norwegian Antarctic Research Expedition (NARE) 1996–97. The simulations suggest that the observed differences between subsurface snow and blue-ice melting can be explained largely by radiative and heat-transfer interactions resulting from differences in albedo, grain-size and density between the two mediums.