The refreezing of melt ponds on Arctic sea ice
The refreezing of melt ponds on Arctic sea ice
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DOI：
10.1002/2014jc010140
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发表时间：
2015-02
影响因子：
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通讯作者：
D. Flocco;D. Feltham;E. Bailey;D. Schroeder
中科院分区：
文献类型：
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作者：
D. Flocco;D. Feltham;E. Bailey;D. Schroeder
北极海冰表面融化池的存在显著降低了其反照率，诱发了一个正反馈，导致海冰变薄。虽然融化池在促进海冰夏季融化方面的作用是众所周知的，但迄今为止，它们对抑制海冰冬季冻结的影响却很少受到关注。融化池通过在表面形成一个冰盖而冻结，这使它们与大气隔绝，并将池中的水困在下面的海冰和冰盖之间。池水是潜热的储存库，在重新冻结时释放出来。在池塘完全冻结之前，底层海冰的底部可能只有很小的冰增长。在这项工作中，我们提出了一个融池再冻结的模型，该模型包括冰盖、被困池和底层海冰中的热量和盐平衡。该模型使用双流辐射模型来解释相边界处的辐射散射。模拟和相关的敏感性研究表明，被困的池塘水可以存活一个多月。我们重点研究了池塘盐度对延迟再冻结过程和减缓基底海冰生长的作用。我们估计，对于一个典型的海冰池秋季覆盖，排除模式中被困池塘的影响，冰增长高估了2.65亿km3，高估了26%。
The presence of melt ponds on the surface of Arctic sea ice significantly reduces its albedo, inducing a positive feedback leading to sea ice thinning. While the role of melt ponds in enhancing the summer melt of sea ice is well known, their impact on suppressing winter freezing of sea ice has, hitherto, received less attention. Melt ponds freeze by forming an ice lid at the upper surface, which insulates them from the atmosphere and traps pond water between the underlying sea ice and the ice lid. The pond water is a store of latent heat, which is released during refreezing. Until a pond freezes completely, there can be minimal ice growth at the base of the underlying sea ice. In this work, we present a model of the refreezing of a melt pond that includes the heat and salt balances in the ice lid, trapped pond, and underlying sea ice. The model uses a two-stream radiation model to account for radiative scattering at phase boundaries. Simulations and related sensitivity studies suggest that trapped pond water may survive for over a month. We focus on the role that pond salinity has on delaying the refreezing process and retarding basal sea ice growth. We estimate that for a typical sea ice pond coverage in autumn, excluding the impact of trapped ponds in models overestimates ice growth by up to 265 million km3, an overestimate of 26%.