The meridional flow of source-driven abyssal currents in a stratified basin with topography. Part II . . .
A numerical simulation is described for source-driven abyssal currents in a 3660 km 3660 km stratified Northern Hemisphere basin with zonally varying topography. The model is the two-layer quasigeostrophic equations, describing the overlying ocean, coupled to the finite-amplitude planetary geostroph...
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Text |
| Language: | English |
| Published: |
2006
|
| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.551.2615 http://pacific.math.ualberta.ca/gordon/publications/abstracts/abyssal2.pdf |
| Summary: | A numerical simulation is described for source-driven abyssal currents in a 3660 km 3660 km stratified Northern Hemisphere basin with zonally varying topography. The model is the two-layer quasigeostrophic equations, describing the overlying ocean, coupled to the finite-amplitude planetary geostrophic equations, describing the abyssal layer, on a midlatitude plane. The source region is a fixed 75 km 150 km area located in the northwestern sector of the basin with a steady downward volume transport of about 5.6 Sv (Sv 106 m3 s1) corresponding to an average downwelling velocity of about 0.05 cm s1. The other parameter values are characteristic of the North Atlantic Ocean. It takes about 3.2 yr for the abyssal water mass to reach the southern boundary and about 25 yr for a statistical state to develop. Time-averaged and instantaneous fields at a late time are described. The time-averaged fields show an equatorward-flowing abyssal current with distinct up- and downslope groundings with decreasing height in the equatorward direction. The average equatorward abyssal transport is about 8 Sv, and the average abyssal current thickness is about 500 m and is about 400 km wide. The circulation in the upper layers is mostly cyclonic and is western intensified, with current speeds about 0.6 cm s1. The upper layer cyclonic circulation intensifies in the source region with speeds about 4 cm s1, and there is an anticyclonic circulation region |
|---|