The Intergyre Chaotic Transport

Zhengyu Liu UCAR Visiting Scientist Program, Atmospheric and Oceanic Sciences Program, Princeton University, Princeton, New Jersey

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Huijun Yang Department of Geophysical Sciences, University of Chicago, Chicago, Illinois

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Abstract

The effect of the annual migration of the wind field on the intergyre transport is investigated in a double-gyre circulation. It is found that the trajectories of the water columns advected by the gyre-scale circulation exhibit a strongly chaotic behavior. The resulted cross-gyre chaotic transport amounts to about one-third of the Sverdrup transport.

The chaotic intergyre transport causes strong mixing between the two gyres. The study with a passive tracer shown that the equivalent diffusivity of the chaotic mixing is at the order of 107 cm2, s−1, comparable to that estimated for strong synoptical eddies in the region of the Gulf Stream. It is suggested that the chaotic transport may contribute significantly to the intergyre exchange.

Further parameter sensitivity studies show that the chaotic transport is the strongest under the migration with frequencies from interannual to decadal, and with the migration distance about 1000 km. Some possible applications of the chaotic transport to the general oceanic circulation are also discussed.

Abstract

The effect of the annual migration of the wind field on the intergyre transport is investigated in a double-gyre circulation. It is found that the trajectories of the water columns advected by the gyre-scale circulation exhibit a strongly chaotic behavior. The resulted cross-gyre chaotic transport amounts to about one-third of the Sverdrup transport.

The chaotic intergyre transport causes strong mixing between the two gyres. The study with a passive tracer shown that the equivalent diffusivity of the chaotic mixing is at the order of 107 cm2, s−1, comparable to that estimated for strong synoptical eddies in the region of the Gulf Stream. It is suggested that the chaotic transport may contribute significantly to the intergyre exchange.

Further parameter sensitivity studies show that the chaotic transport is the strongest under the migration with frequencies from interannual to decadal, and with the migration distance about 1000 km. Some possible applications of the chaotic transport to the general oceanic circulation are also discussed.

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