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The impact of finite-amplitude bottom topography on internal wave generation in the Southern Ocean
Citation
Nikurashin, M and Ferrari, R and Grisouard, N and Polzin, N, The impact of finite-amplitude bottom topography on internal wave generation in the Southern Ocean, Journal of Physical Oceanography, 44, (11) pp. 2938-2950. ISSN 0022-3670 (2014) [Refereed Article]
Copyright Statement
Copyright 2014 American Meteorological Society
DOI: doi:10.1175/JPO-D-13-0201.1
Abstract
Direct observations in the Southern Ocean report enhanced internal wave activity and turbulence in
a kilometer-thick layer above rough bottom topography collocated with the deep-reaching fronts of the Antarctic
Circumpolar Current. Linear theory, corrected for finite-amplitude topography based on idealized, two dimensional
numerical simulations, has been recently used to estimate the global distribution of internal wave
generation by oceanic currents and eddies. The global estimate shows that the topographic wave generation is
a 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 the
Southern Ocean shows that the linear theory predictions and idealized two-dimensional simulations grossly
overestimate 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 topography
with 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 primarily
associated with finite-amplitude bottom topography effects that suppress vertical motions and thus reduce
the amplitude of the internal waves radiated from topography. The implication of these results for the global lee wave
generation is discussed.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Keywords: | ocean mixing, internal waves, mixing parameterization, lee waves, topography |
| Research Division: | Earth Sciences |
| Research Group: | Oceanography |
| Research Field: | Physical oceanography |
| Objective Division: | Environmental Policy, Climate Change and Natural Hazards |
| Objective Group: | Understanding climate change |
| Objective Field: | Climate change models |
| UTAS Author: | Nikurashin, M (Dr Maxim Nikurashin) |
| ID Code: | 96512 |
| Year Published: | 2014 |
| Web of Science® Times Cited: | 42 |
| Deposited By: | IMAS Research and Education Centre |
| Deposited On: | 2014-11-10 |
| Last Modified: | 2017-11-01 |
| Downloads: | 0 |
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