Editorial Type:
Article
Article Type:
Research Article

Southward Eddy Heat Transport Occurring along Southern Flanks of the Kuroshio Extension and the Gulf Stream in a 1/10° Global Ocean General Circulation Model

Kunihiro Aoki Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Japan

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Shoshiro Minobe Department of Natural History Sciences, Graduate School of Science, Hokkaido University, Sapporo, Japan

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Youichi Tanimoto Faculty of Environmental Earth Science, Hokkaido University, Sapporo, and Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan

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Yoshikazu Sasai Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan

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Print Publication:
01 Sep 2013
DOI:
https://doi.org/10.1175/JPO-D-12-0223.1
Page(s):
1899–1910
Restricted access

Abstract

The present study investigates meridional heat transport induced by oceanic mesoscale variability in the World Ocean using a ° global ocean general circulation model (OGCM) running on the Earth Simulator. The results indicate prominent poleward eddy heat transport around the western boundary currents and the Antarctic Circumpolar Current, and equatorward eddy heat transport in the equatorial region, consistent with the previous studies using coarse-resolution OGCMs. Such poleward eddy heat transport in midlatitude oceans suggests that the eddies act to reduce meridional background temperature gradients across the currents, as would be expected based on baroclinic instability. Interestingly, however, along the southern flanks of the eastward jets of the Kuroshio Extension and the Gulf Stream, southward eddy heat transport occurs in subsurface layers. This is likely due to the southward migration of warm water cores originating from southern areas adjacent to these currents. Southward movement of these cores is caused by interactions with unsteady meanders and cold eddies detaching from the meanders. The potential impact on biological production in the subtropical surface layers of these southward-traveling warm water cores is also discussed.

Corresponding author address: Kunihiro Aoki, Graduate School of Environmental Earth Science, Hokkaido University, N10W5, Sapporo 060-0810, Japan. E-mail: aokik@ees.hokudai.ac.jp

Abstract

The present study investigates meridional heat transport induced by oceanic mesoscale variability in the World Ocean using a ° global ocean general circulation model (OGCM) running on the Earth Simulator. The results indicate prominent poleward eddy heat transport around the western boundary currents and the Antarctic Circumpolar Current, and equatorward eddy heat transport in the equatorial region, consistent with the previous studies using coarse-resolution OGCMs. Such poleward eddy heat transport in midlatitude oceans suggests that the eddies act to reduce meridional background temperature gradients across the currents, as would be expected based on baroclinic instability. Interestingly, however, along the southern flanks of the eastward jets of the Kuroshio Extension and the Gulf Stream, southward eddy heat transport occurs in subsurface layers. This is likely due to the southward migration of warm water cores originating from southern areas adjacent to these currents. Southward movement of these cores is caused by interactions with unsteady meanders and cold eddies detaching from the meanders. The potential impact on biological production in the subtropical surface layers of these southward-traveling warm water cores is also discussed.

Corresponding author address: Kunihiro Aoki, Graduate School of Environmental Earth Science, Hokkaido University, N10W5, Sapporo 060-0810, Japan. E-mail: aokik@ees.hokudai.ac.jp
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