The impact of finite-amplitude bottom topography on internal wave generation in the Southern Ocean
Direct observations in the Southern Ocean report enhanced internal wave activity and turbulence ina kilometer-thick layer above rough bottom topography collocated with the deep-reaching fronts of the AntarcticCircumpolar Current. Linear theory, corrected for finite-amplitude topography based on idea...
| Published in: | Journal of Physical Oceanography |
|---|---|
| Main Authors: | , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Amer Meteorological Soc
2014
|
| Subjects: | |
| Online Access: | https://doi.org/10.1175/JPO-D-13-0201.1 http://ecite.utas.edu.au/96512 |
| Summary: | Direct observations in the Southern Ocean report enhanced internal wave activity and turbulence ina kilometer-thick layer above rough bottom topography collocated with the deep-reaching fronts of the AntarcticCircumpolar Current. Linear theory, corrected for finite-amplitude topography based on idealized, two dimensionalnumerical simulations, has been recently used to estimate the global distribution of internal wavegeneration by oceanic currents and eddies. The global estimate shows that the topographic wave generation isa significant sink of energy for geostrophic flows and a source of energy for turbulent mixing in the deep ocean.However, comparison with recent observations from the Diapycnal and Isopycnal Mixing Experiment in theSouthern Ocean shows that the linear theory predictions and idealized two-dimensional simulations grosslyoverestimate the observed levels of turbulent energy dissipation. This study presents two- and three-dimensional,realistic topography simulations of internal lee-wave generation from a steady flow interacting with topographywith parameters typical of Drake Passage. The results demonstrate that internal wave generation at three dimensional,finite bottom topography is reduced compared to the two-dimensional case. The reduction is primarilyassociated with finite-amplitude bottom topography effects that suppress vertical motions and thus reducethe amplitude of the internal waves radiated from topography. The implication of these results for the global lee wavegeneration is discussed. |
|---|