2076 JOURNAL OF PHYSICAL OCEANOGRAPHY VOLUME 35 Adjustment of the Southern Ocean to Wind Forcing on Synoptic Time Scales
This study addresses the response of the Southern Ocean to high-frequency wind forcing, focusing on the impact of several barotropic modes on the circumpolar transport. A suite of experiments is performed with an unstratified model of the Southern Ocean, forced with a stochastic wind stress that con...
| Main Authors: | , , |
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| Format: | Text |
| Language: | English |
| Published: |
2004
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| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.411.8233 http://www-pord.ucsd.edu/~sgille/pub_dir/weijer_gille05.pdf |
| Summary: | This study addresses the response of the Southern Ocean to high-frequency wind forcing, focusing on the impact of several barotropic modes on the circumpolar transport. A suite of experiments is performed with an unstratified model of the Southern Ocean, forced with a stochastic wind stress that contains a large range of frequencies with synoptic time scales. The Southern Ocean adjustment displays a different character for frequencies below and above 0.2 cpd. The low-frequency range is dominated by an “almost-free-mode” response in the region where contours of f/H are obstructed by only a few bathymetric features; the truly free mode only plays a minor role. Topographic form stress, rather than friction, is the dominant decay mechanism of the Southern Mode. It leads to a spindown time scale on the order of 3 days. For the high-frequency range, the circumpolar transport is dominated by the resonant excitation of oscillatory modes. The “active ” response of the ocean leads to strong changes and even discontinuities in the phase relation between transport and wind stress. 1. |
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