University of Cambridge > Talks.cam > British Antarctic Survey - Polar Oceans seminar series > Deep-reaching global ocean overturning circulation generated by surface buoyancy forcing

Deep-reaching global ocean overturning circulation generated by surface buoyancy forcing

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If you have a question about this talk, please contact Dr. Shenjie Zhou.

In contrast with the atmosphere, which is heated from below by solar radiation, the ocean is heated and cooled at the surface. To drive a large-scale overturning circulation in this context, it is generally assumed that either interior mixing by winds and tides, or wind-driven pumping is required; in their absence, the circulation is thought to collapse to a shallow surface cell. We demonstrate, using a primitive equation model with an idealized domain, that surface temperature forcing alone can drive an inter-hemisphere overturning provided that there is a channel unblocked in the zonal direction, such as in the Southern Ocean. With this geometry, rotating horizontal convection, in combination with asymmetric surface cooling between the north and south, drives a deep-reaching two-cell overturning circulation. The resulting vertical stratification closely resembles that in the real ocean, suggesting buoyancy forcing plays a much larger role in the climate system than usually assumed.

This talk is part of the British Antarctic Survey - Polar Oceans seminar series series.

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