Kelvin waves around Antarctica

• Published in: Journal of Physical Oceanography
• Main Authors: Kusahara, K, Ohshima, KI
• Format: Article in Journal/Newspaper
• Language: English
• Published: Amer Meteorological Soc 2014
• Subjects: Earth Sciences; Oceanography; Physical Oceanography; Antarctic; Drake Passage; Pacific; Southern Ocean; The Antarctic; Antarc*; Antarctica; Antarctica Journal
• Online Access: https://doi.org/10.1175/JPO-D-14-0051.1; http://ecite.utas.edu.au/109883

The Southern Ocean allows circumpolar structure and the Antarctic coastline plays a role as a waveguide foroceanic Kelvin waves. Under the cyclic conditions, the horizontal wavenumbers and frequencies for circumpolarlypropagating waves are quantized, with horizontal wavenumbers 1, 2, and 3, corresponding to periods ofabout 32, 16, and 11 h, respectively. At these frequencies, westward-propagating signals are detected in sea levelvariation observed at Antarctic coastal stations. The occurrence frequency of westward-propagating signals farexceeds the statistical significance, and the phase speed of the observed signal agrees well with the theoreticalphase speed of external Kelvin waves. Therefore, this study concludes that the observed, westward-propagatingsea level variability is a signal of the external Kelvin waves of wavenumbers 1, 2, and 3 around Antarctica. Aseries of numerical model experiments confirms that Kelvin waves around Antarctica are driven by surface airpressure and that these waves are excited not only by local forcing over the Southern Ocean, but also by remoteforcing over the Pacific Ocean. Sea level variations generated over the Pacific Ocean can travel to the westernside of the South American coast and cross over Drake Passage to the Antarctic continent, constituting a part ofthe Kelvin waves around Antarctica.