A Mathematical Model of Melt Lake Development on an Ice Shelf
A Mathematical Model of Melt Lake Development on an Ice Shelf
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DOI：
10.1002/2017ms001155
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发表时间：
2018-02-01
影响因子：
6.8
通讯作者：
Flocco, D.
中科院分区：
文献类型：
--
作者：
Buzzard, S. C.;Feltham, D. L.;Flocco, D.
表面融水在冰架上的积累会导致融水湖的形成。融湖与冰架崩塌有关；据观测，在2002年南极洲的拉森B冰架崩塌之前，有大量的表面融化湖。这种崩塌会影响海洋环流和温度，造成栖息地丧失，并通过支流冰川加速导致海平面上升。我们提出了一个理想冰架上表面融湖的数学模型。该模型计算了冰架表面能量平衡、冰架内部的热量传递、冰架内部融水的产生和渗透、冰透镜的形成以及冰架表面融水湖的形成和再冻结。该模型应用于拉森C冰架，在那里已经观测到融化湖。上个世纪，该地区的变暖程度是全球平均水平的几倍，到本世纪末，拉森C冰层可能会被融水饱和。当使用气象站数据时，我们的模式产生的地表融化、融水积累和融湖发展与观测结果一致。我们研究了湖泊形成对不确定参数的敏感性，并提供了证据，证明了侧向融水输送等过程的重要性。我们的结论是，融水湖影响地表融水和冰密度，因此有必要将其纳入气候模型中冰架演化的动态热力学模型，而我们的模型可以成为热力学成分的基础。
The accumulation of surface meltwater on ice shelves can lead to the formation of melt lakes. Melt lakes have been implicated in ice shelf collapse; Antarctica's Larsen B Ice Shelf was observed to have a large amount of surface melt lakes present preceding its collapse in 2002. Such collapse can affect ocean circulation and temperature, cause habitat loss and contribute to sea level rise through the acceleration of tributary glaciers. We present a mathematical model of a surface melt lake on an idealized ice shelf. The model incorporates a calculation of the ice shelf surface energy balance, heat transfer through the firn, the production and percolation of meltwater into the firn, the formation of ice lenses, and the development and refreezing of surface melt lakes. The model is applied to the Larsen C Ice Shelf, where melt lakes have been observed. This region has warmed several times the global average over the last century and the Larsen C firn layer could become saturated with meltwater by the end of the century. When forced with weather station data, our model produces surface melting, meltwater accumulation, and melt lake development consistent with observations. We examine the sensitivity of lake formation to uncertain parameters and provide evidence of the importance of processes such as lateral meltwater transport. We conclude that melt lakes impact surface melt and firn density and warrant inclusion in dynamic-thermodynamic models of ice shelf evolution within climate models, of which our model could form the basis for the thermodynamic component.