Enhancement of sea-ice drift due to the dynamical interaction between sea ice and a coastal ocean
Enhancement of sea-ice drift due to the dynamical interaction between sea ice and a coastal ocean
复制标题
海冰与沿海海洋之间的动力相互作用导致海冰漂移增强
DOI：
10.1175/jpo-d-11-018.1
复制
发表时间：
2012
影响因子：
3.5
通讯作者：
Yoshihiro
中科院分区：
文献类型：
--
作者：
Nakayama;Yoshihiro
风因子是海冰漂移速度与海面风速的比值，是海冰动力学的关键因子，一般约为2%。然而，在一些沿海海洋，风的因素往往在海岸附近更大。本文提出了海冰与近岸海洋动力耦合对海冰漂移的增强机制。在被海冰覆盖的沿海海洋中，风驱动的海冰漂移激发沿海被困波（陆架波）并产生波动的洋流。当海流方向与风驱动的漂移方向相同时，这种海流可以增强海冰的漂移。作者考虑了一个简化的设置，空间均匀的振荡风平行于海岸漂移海冰。当海洋响应假定为正压长陆架波时，得到了风和海洋共同驱动的海冰漂移的解析解。海洋驱动的海冰漂移和风驱动的海冰漂移的比率用于评估海洋对海冰漂移增强的贡献。海冰漂移的增强主要取决于陆架波的特征，在低频风强迫下，海冰漂移在靠近海岸的地方显著增强。通过与萨哈林海岸观测资料的比较，发现海冰漂移增强的程度及其在海岸附近增强幅度较大的特征与我们的理论解基本一致，表明这种机制在真实的海洋中是存在的。
Wind factor, the ratio of sea ice drift speed to surface wind speed, is a key factor for the dynamics of sea ice and is generally about 2%. In some coastal oceans, however, the wind factor tends to be larger near the coast. This study proposes the enhancement mechanism of the sea ice drift caused by the dynamical coupling between sea ice and a coastal ocean. In a coastal ocean covered with sea ice, wind-forced sea ice drift excites coastal trapped waves (shelf waves) and generates fluctuating ocean current. This ocean current can enhance sea ice drift when the current direction is the same as that of the wind-driven drift. The authors consider a simplified setting where spatially uniform oscillating wind drifts sea ice parallel to the coast. When a barotropic long shelf wave is assumed for the ocean response, sea ice drifts driven by wind and ocean are obtained analytically. The ratio of ocean-driven to wind-driven sea ice drifts is used for the evaluation of the oceanic contribution to the enhancement of sea ice drift. The enhancement is mostly determined by the characteristics of the shelf waves, and sea ice drift is significantly enhanced close to the coast with lower-frequency wind forcing. Comparison with the observation off the Sakhalin coast shows that the degree of enhancement of sea ice drift and its characteristic such that larger enhancement occurs near the coast are mostly consistent with our theoretical solution, suggesting that this mechanism is present in the real ocean.