Kelvin Waves around Antarctica
Kelvin Waves around Antarctica
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DOI：
10.1175/jpo-d-14-0051.1
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发表时间：
2014-11-01
影响因子：
3.5
通讯作者：
Ohshima, Kay I.
中科院分区：
文献类型：
--
作者：
Kusahara, Kazuya;Ohshima, Kay I.
南大洋允许环极结构，南极海岸线起着海洋开尔文波的波导作用。在循环条件下，绕极传播波的水平波数和频率被量化，水平波数为1、2和3，分别对应于约32、16和11 h的周期。在这些频率下，在南极沿海站观测到的海平面变化中检测到向西传播的信号。西传信号的出现频率远远超过统计显着性，观测信号的相速度与外开尔文波的理论相速度非常吻合。因此，本研究得出的结论是，观测到的向西传播的海平面变化是南极洲周围波数1、2和3的外部开尔文波的信号。一系列数值模型实验证实，南极洲周围的开尔文波是由地表气压驱动的，这些波不仅受到南大洋上的局部强迫的激发，而且还受到太平洋上空远程强迫的激发。太平洋上空产生的海平面变化可以传播到南美海岸的西侧，穿过德雷克海峡到达南极大陆，构成南极洲周围开尔文波的一部分。
The Southern Ocean allows circumpolar structure and the Antarctic coastline plays a role as a waveguide for oceanic Kelvin waves. Under the cyclic conditions, the horizontal wavenumbers and frequencies for circum-polarly propagating waves are quantized, with horizontal wavenumbers 1, 2, and 3, corresponding to periods of about 32, 16, and 11 h, respectively. At these frequencies, westward-propagating signals are detected in sea level variation observed at Antarctic coastal stations. The occurrence frequency of westward-propagating signals far exceeds the statistical significance, and the phase speed of the observed signal agrees well with the theoretical phase speed of external Kelvin waves. Therefore, this study concludes that the observed, westward-propagating sea level variability is a signal of the external Kelvin waves of wavenumbers 1, 2, and 3 around Antarctica. A series of numerical model experiments confirms that Kelvin waves around Antarctica are driven by surface air pressure and that these waves are excited not only by local forcing over the Southern Ocean, but also by remote forcing over the Pacific Ocean. Sea level variations generated over the Pacific Ocean can travel to the western side of the South American coast and cross over Drake Passage to the Antarctic continent, constituting a part of the Kelvin waves around Antarctica.