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| activités | bourse | liens | membres | contact | ||
date |
Mardi, 30 septembre 2008 |
lieu |
INRS-ETE
(salle 2417) |
| heure
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12h00 |
| Eric
Kunze SEOS
and Physics-Astronomy, University of Victoria
|
|
Ocean
Abyssal Mixing and the Meridional Overturning Cell
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The
ocean's meridional overturning circulation arises
from the formation of the world's coldest and densest water-masses
(Antarctic Bottom Water) on Antarctic shelves and seas, their sinking
and spreading to fill the bottom 1 km of the world ocean, and subsequent upwelling and warming through turbulent mixing. Bulk estimates of the turbulent diffusivity K are O(1 cm^2/s). But direct microstructure measurements typically find K~0.1 cm^2/s. This has led to the suggestion that mixing may be concentrated near rough ocean topography or where density surfaces outcrop at high latitudes. I will discuss the present state of confusion about deep-ocean mixing, including recent microstructure measurements near various kinds of topography and a global assessment using a mixing parameterization based on internal wave/wave interaction theory applied to O(3500 m) full-depth profiles. |
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