| Zhang Xueyan,Dai Haijin,Zhao Jun,Yin Heqing. 2020. Sensitivity study of the wave-driven current in an Arctic frazil-pancake ice zone. Acta Oceanologica Sinica, 39(3):123－129 |
| Sensitivity study of the wave-driven current in an Arctic frazil-pancake ice zone |
| 北极薄冰-煎饼冰区域中不同重力波驱动形成海流的敏感性分析 |
| Received:May 20, 2019 |
| DOI：10.1007/s13131-020-1560-x |
| Key words:marginal ice zone frazil-pancake ice wave dissipation ice-edge jet mesoscale eddy genesis |
| 中文关键词: 海冰边缘区 薄饼-煎饼冰 波衰减 冰边缘急流 中尺度涡生成 |
| 基金项目:The National University of Defense Technology under contract No. ZK18-03-29. |
| Author Name | Affiliation | E-mail | | Zhang Xueyan | College of Meteorology and Oceanography, National University of Defense Technology, Changsha 410073, China | | | Dai Haijin | College of Meteorology and Oceanography, National University of Defense Technology, Changsha 410073, China | hj_dai@nudt.edu.cn | | Zhao Jun | College of Meteorology and Oceanography, National University of Defense Technology, Changsha 410073, China | | | Yin Heqing | College of Meteorology and Oceanography, National University of Defense Technology, Changsha 410073, China | |
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| Abstract: |
| A coupled ocean-ice-wave model is used to study ice-edge jet and eddy genesis during surface gravity wave dissipation in a frazil-pancake ice zone. With observational data from the Beaufort Sea, possible wave dissipation processes are evaluated using sensitivity experiments. As wave energy dissipated, energy was transferred into ice floe through radiation stress. Later, energy was in turn transferred into current through ocean-ice interfacial stress. Since most of the wave energy is dissipated at the ice edge, ice-edge jets, which contained strong horizontal shear, appeared both in the ice zone and the ocean. Meanwhile, the wave propagation direction determines the velocity partition in the along-ice-edge and cross-ice-edge directions, which in turn determines the strength of the along-ice-edge jet and cross-ice-edge velocity. The momentum applied in the along-ice-edge (cross-ice-edge) direction increased (decreased) with larger incident angle, which is favorable condition for producing stronger mesoscale eddies, vice versa. The dissipation rate increases (decreases) with larger (smaller) wavenumber, which enhances (reduces) the jet strength and the strength of the mesoscale eddy. The strong along-ice-edge jet may extend to a deep layer (> 200 m). If the water depth is too shallow (e.g., 80 m), the jet may be largely dampened by bottom drag, and no visible mesoscale eddies are found. The results suggest that the bathymetry and incident wavenumber (magnitude and propagation direction) are important for wave-driven current and mesoscale eddy genesis. |
| 中文摘要: |
| 本文利用海洋-海冰-波浪耦合模式研究了在以薄冰-煎饼冰为主的海冰边缘区域里，冰边缘急流和中尺度涡在表面重力波衰减过程中的形成机制。利用楚科奇海的观测和恢复数据，设计敏感性实验，研究可能发生的重力波衰减过程。当波能量被耗散时，能量通过辐射应力的形式传递到浮冰中，进而由于海水和海冰之间的摩擦应力传递到海流中。因为大部分波能量耗散在海冰边缘，在海冰区域和海洋中都会产生具有很强水平剪切的冰边缘急流。波的传播方向决定沿冰边缘和垂直冰边缘方向上的速度分量，进而决定沿冰边缘方向急流的强度和垂直冰边缘方向海流的速度。沿冰边缘（垂直冰边缘）方向动量随着入射角的增大而增加（减少），有利于产生更强的中尺度涡，反之亦然。耗散率随着波数的增大（减小）而增加（减少），急流强度和中尺度涡的强度增加（降低）。较强的冰边缘急流可以延伸到更深的海水中（大于200米），如果水深较浅（例如80米），被底部摩擦耗散掉的急流动量会大幅增加，以至于没有中尺度涡生成。结果表明，水深和入射波数（大小和传播方向）对波驱动的海流和中尺度涡生成的影响非常重要。 |
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