Open AccessSensitivity of the Ocean State to Lee Wave–Driven Mixing
Author(s) -
Angélique Mélet,
Robert Hallberg,
Sonya Legg,
Maxim Nikurashin
Publication year - 2014
Publication title -
journal of physical oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.706
H-Index - 143
eISSN - 1520-0485
pISSN - 0022-3670
DOI - 10.1175/jpo-d-13-072.1
Subject(s) - internal wave , barotropic fluid , stratification (seeds) , internal tide , geology , baroclinity , mixing (physics) , geophysics , geostrophic wind , ocean dynamics , energy flux , thermohaline circulation , physical oceanography , ocean general circulation model , ocean current , climatology , breaking wave , oceanography , wave propagation , physics , general circulation model , climate change , seed dormancy , botany , germination , quantum mechanics , dormancy , biology , astronomy
Diapycnal mixing plays a key role in maintaining the ocean stratification and the meridional overturning\udcirculation (MOC). In the ocean interior, it is mainly sustained by breaking internal waves. Two important\udclasses of internal waves are internal tides and lee waves, generated by barotropic tides and geostrophic flows\udinteracting with rough topography, respectively. Currently, regarding internal wave–driven mixing, most\udclimate models only explicitly parameterize the local dissipation of internal tides. In this study, the authors\udexplore the combined effects of internal tide– and lee wave–driven mixing on the ocean state. A series of\udsensitivity experiments using the Geophysical Fluid Dynamics Laboratory CM2G ocean–ice–atmosphere\udcoupled model are performed, including a parameterization of lee wave–driven mixing using a recent estimate\udfor the global map of energy conversion into lee waves, in addition to the tidal mixing parameterization. It is\udshown that, although the global energy input in the deep ocean into lee waves (0.2 TW; where 1 TW51012W)\udis small compared to that into internal tides (1.4 TW), lee wave–driven mixing makes a significant impact on\udthe ocean state, notably on the ocean thermal structure and stratification, as well as on the MOC. The vertically\udintegrated circulation is also impacted in the Southern Ocean, which accounts for half of the lee wave\udenergy flux. Finally, it is shown that the different spatial distribution of the internal tide and lee wave energy\udinput impacts the sensitivity described in this study. These results suggest that lee wave–driven mixing should\udbe parameterized in climate models, preferably using more physically based parameterizations that allow the\udinternal lee wave–driven mixing to evolve in a changing ocean