Dynamics of Global Ocean Heat Transport Variability
A state-of-the-art, high-resolution ocean general circulation model is used to estimate the time-dependent global ocean heat transport and investigate its dynamics. Globally, the cross-equatorial, seasonal heat transport fluctuations are close to +/- 4.5 x 10(exp 15) watts, the same amplitude as the...
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| Format: | Text |
| Language: | English |
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1999
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| Online Access: | http://www.dtic.mil/docs/citations/ADA369166 http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA369166 |
| Summary: | A state-of-the-art, high-resolution ocean general circulation model is used to estimate the time-dependent global ocean heat transport and investigate its dynamics. Globally, the cross-equatorial, seasonal heat transport fluctuations are close to +/- 4.5 x 10(exp 15) watts, the same amplitude as the seasonal, cross-equatorial atmospheric energy transport. The majority of it is due to wind-induced current fluctuations in which the time-varying wind drives Ekman layer mass transports that are compensated by depth-independent return flows. The temperature difference between the mass transports gives rise to the time-dependent heat transport. The rectified eddy heat transport is calculated from the model. It is weak in the central gyres, and strong in the western boundary currents, the Antarctic Circumpolar Current, and the equatorial region. It is largely confined to the upper 1000 meters of the ocean. The rotational component of the eddy heat transport is strong in the oceanic jets, while the divergent component is strongest in the equatorial region and Antarctic Circumpolar Current. The method of estimating the eddy beat transport from an eddy diffusivity derived from mixing length arguments and altimetry data, and the climatological temperature field, is tested and shown not to reproduce the model's directly evaluated eddy heat transport. |
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