A simple model for the evolution of melt pond coverage on permeable Arctic sea ice
A simple model for the evolution of melt pond coverage on permeable Arctic sea ice
复制标题
可渗透性北极海冰融化池覆盖演变的简单模型
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
D. Abbot
中科院分区：
文献类型：
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作者：
P. Popović;D. Abbot
抽象的。随着融化季节的进行，北极的海冰往往变得具有足够的渗透性，可以几乎完全排出冰表面上收集的融水。排水后留下的融化池在水力上与海洋相连，相当于表面低于海平面的海冰区域。我们提出了一个简单的模型，在这种可渗透的海冰浮冰上的融化池覆盖的演变，我们允许空间变化的冰融化率，并假设整个浮冰是在流体静力平衡。该模型由两个简单的常微分方程表示，其中池塘覆盖率的变化率取决于池塘覆盖率。系统的所有物理参数都由四个强度来概括，这四个强度控制着方程中各项的相对重要性。该模型既符合观测结果，又使我们能够以一种更复杂的模型通常不可能实现的方式了解融化池的行为。我们可以从模型中获得的见解的例子是，（1）池塘的增长率是更敏感的变化裸海冰的冰比池塘的冰的变化，（2）池塘生长较慢的平滑的冰，（3）池塘响应最强的干舷下沉的第一年冰和侧壁融化多年的冰。我们还表明，在全球变暖的情况下，池塘覆盖率将增加，减少整体冰覆盖率，并导致冰变薄，这可能是由于直接强迫变薄。由于融化池覆盖率是控制海冰覆盖率的关键参数之一，了解控制池塘覆盖率分布的机制将有助于改善大尺度模型参数化和气候变暖中的海冰预测。
Abstract. As the melt season progresses, sea ice in the Arctic often becomes permeable enough to allow for nearly complete drainage of meltwater that has collected on the ice surface. Melt ponds that remain after drainage are hydraulically connected to the ocean and correspond to regions of sea ice whose surface is below sea level. We present a simple model for the evolution of melt pond coverage on such permeable sea ice floes in which we allow for spatially varying ice melt rates and assume the whole floe is in hydrostatic balance. The model is represented by two simple ordinary differential equations, where the rate of change of pond coverage depends on the pond coverage. All the physical parameters of the system are summarized by four strengths that control the relative importance of the terms in the equations. The model both fits observations and allows us to understand the behavior of melt ponds in a way that is often not possible with more complex models. Examples of insights we can gain from the model are that (1) the pond growth rate is more sensitive to changes in bare sea ice albedo than changes in pond albedo, (2) ponds grow slower on smoother ice, and (3) ponds respond strongest to freeboard sinking on first-year ice and sidewall melting on multiyear ice. We also show that under a global warming scenario, pond coverage would increase, decreasing the overall ice albedo and leading to ice thinning that is likely comparable to thinning due to direct forcing. Since melt pond coverage is one of the key parameters controlling the albedo of sea ice, understanding the mechanisms that control the distribution of pond coverage will help improve large-scale model parameterizations and sea ice forecasts in a warming climate.