ABSTRACT

The Kitikmeot Sea is a semi-enclosed, east–west waterway in the southern Canadian Arctic Archipelago (CAA). In the present work, the ice conditions, stratification, and circulation of the Kitikmeot Sea are diagnosed using numerical simulations with a 1/12° resolution. The physical oceanographic conditions of the Kitikmeot Sea are different from channels in the northern CAA due to the existence of a substantial ice-free period each year. The consequences of such ice conditions are twofold. First, through fluctuations of external forcings, such as solar radiation and wind stress, acting directly or indirectly on the sea surface, the seasonal ice coverage leads to significant seasonal variations in both stratification and circulation. Our simulation results suggest that such variations include freshening and deepening of the surface layer, in which salinity can reach as low as 15 during the peak runoff season, and significantly stronger along-shore currents driven directly by the wind stress during the ice-free season. The second consequence is that the sea ice is not landfast but can move freely during the melting season. By analyzing the relative importance of thermodynamic (freezing and/or melting) and dynamic (ice movement) processes to the ice dynamics, our simulation results suggest that there is a net inflow of sea ice into the Kitikmeot Sea, which melts locally each summer. The movement of sea ice thus provides a significant freshwater pathway, which contributes approximately 14 km³ yr⁻¹ of fresh water to the Kitikmeot Sea, on average, equivalent to a third of freshwater input from runoff from the land.

摘要

Kitikmeot 海是位于加拿大北极群岛 (CAA) 南部的一条半封闭的东西向水道。在目前的工作中，使用分辨率为 1/12° 的数值模拟来诊断 Kitikmeot 海的冰况、分层和环流。由于每年存在大量无冰期，Kitikmeot 海的物理海洋条件与 CAA 北部的航道不同。这种冰况的后果是双重的。首先，通过直接或间接作用于海面的太阳辐射和风应力等外强迫的波动，季节性冰层覆盖导致分层和环流的显着季节性变化。我们的模拟结果表明，这种变化包括表层的更新和加深，其中，在径流高峰季节盐度可低至 15，而在无冰季节直接由风应力驱动的沿岸水流明显增强。第二个后果是海冰不能固定在陆地上，但在融化季节可以自由移动。通过分析热力学（冻结和/或融化）和动态（冰运动）过程对冰动力学的相对重要性，我们的模拟结果表明，每年夏天都有海冰净流入 Kitikmeot 海，该海在局部融化。因此，海冰的移动提供了一条重要的淡水通道，贡献了大约 14 公里 第二个后果是海冰不能固定在陆地上，但在融化季节可以自由移动。通过分析热力学（冻结和/或融化）和动态（冰运动）过程对冰动力学的相对重要性，我们的模拟结果表明，每年夏天都有海冰净流入 Kitikmeot 海，该海在局部融化。因此，海冰的移动提供了一条重要的淡水通道，贡献了大约 14 公里 第二个后果是海冰不能固定在陆地上，但在融化季节可以自由移动。通过分析热力学（冻结和/或融化）和动态（冰运动）过程对冰动力学的相对重要性，我们的模拟结果表明，每年夏天都有海冰净流入 Kitikmeot 海，该海在局部融化。因此，海冰的移动提供了一条重要的淡水通道，贡献了大约 14 公里³年^-1的淡水流入 Kitikmeot 海，平均相当于来自陆地径流的淡水输入量的三分之一。