Fu, Yao (2013) Equatorial deep jets: Modelling and observation. (Master thesis), Christian-Albrechts-Universität Kiel, Kiel, Germany, 60 pp.

Preview

Text masterthesis_YFu.pdf - Published Version Available under License German copyright act UrhG. Download (1MB) | Preview

Abstract

The equatorial deep jets (EDJs) are strong vertically alternating zonal ows extending over almost the full depth of the equatorial oceans. They are trapped in a narrow equatorial band of roughly 1° latitude about the equator, associated with a vertical scale of between 300 m and 700 m; in the Atlantic Ocean, they have a time scale of about 4.5 years. The crossequatorial width of the EDJs is found to be roughly 1.5 times larger than implied by the linear inviscid theory based on their vertical scale. In this work, EDJs are simulated using a forced, dissipative low-frequency equatorial basin mode in a shallow water model associated with a high-order baroclinic vertical normal mode. The lateral mixing of momentum is found to result in a widening of the simulated EDJs; the widening of the EDJs by the lateral mixing of momentum is considered as one of the explanations of the enhanced cross-equatorial width of the observed EDJs. The zonal velocities measured by the Argo floats are used for comparison of the meridional profiles and the flow strength with the simulations. A value of 300 m2/s for the lateral mixing coefficient is found to be sufficient to account for the observed width of the EDJs; also, the implementation of the background barotropic mean flow leads to a better agreement with the observations at latitudes higher than 2,5° either side of the equator.

Actions (login required)

View Item