Dynamics and Thermodynamics of the Mean Transpolar Drift and Ice Thickness in the Arctic Ocean
Dynamics and Thermodynamics of the Mean Transpolar Drift and Ice Thickness in the Arctic Ocean
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DOI：
10.1175/jcli-d-19-0252.1
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发表时间：
2019-11
影响因子：
4.9
通讯作者：
M. Spall
中科院分区：
文献类型：
--
作者：
M. Spall
本文提出了北冰洋平均冰厚和跨极漂移的理论。冰的动量和厚度方程的渐近展开，推导出解析表达式的领先阶冰的厚度和速度场风应力强迫和热损失到大气中。该理论是最合适的北极东部和中部，但不适用于该地区的博福特环流受反气旋风应力旋度。尺度分析揭示了两个不同的制度：在北极东部的薄冰制度和厚冰制度在北极西部。在北极东部，冰的漂移是由风和海洋阻力之间的平衡控制的，而冰的厚度是由大气中的热量损失控制的。相比之下，在北极西部，冰的厚度是由风和内部冰应力之间的平衡决定的，而漂移是由大气中的热损失间接控制的。冰厚的横风向梯度迫使流向弗拉姆海峡的气流向南流动。冰厚度，热损失，冰量，冰出口的理论比较理想化的，耦合的海洋冰数值模型在很宽的参数空间的基本预测。该理论表明，大气温度或风速的增加会导致最大冰厚和冰量的减少。气温升高还导致通过弗拉姆海峡向大气的热损失和冰输出减少，而风力增加则导致热损失和冰输出增加。
A theory for the mean ice thickness and the Transpolar Drift in the Arctic Ocean is developed. Asymptotic expansions of the ice momentum and thickness equations are used to derive analytic expressions for the leading-order ice thickness and velocity fields subject to wind stress forcing and heat loss to the atmosphere. The theory is most appropriate for the eastern and central Arctic, but not for the region of the Beaufort Gyre subject to anticyclonic wind stress curl. The scale analysis reveals two distinct regimes: a thin ice regime in the eastern Arctic and a thick ice regime in the western Arctic. In the eastern Arctic, the ice drift is controlled by a balance between wind and ocean drag, while the ice thickness is controlled by heat loss to the atmosphere. In contrast, in the western Arctic, the ice thickness is determined by a balance between wind and internal ice stress, while the drift is indirectly controlled by heat loss to the atmosphere. The southward flow toward Fram Strait is forced by the across-wind gradient in ice thickness. The basic predictions for ice thickness, heat loss, ice volume, and ice export from the theory compare well with an idealized, coupled ocean–ice numerical model over a wide range of parameter space. The theory indicates that increasing atmospheric temperatures or wind speed result in a decrease in maximum ice thickness and ice volume. Increasing temperatures also result in a decrease in heat loss to the atmosphere and ice export through Fram Strait, while increasing winds drive increased heat loss and ice export.