Abstract
The flow pattern of the North Atlantic Subtropical Gyre (NASG) is simulated using a highly idealised one-layer quasi-geostrophic wind-driven model. The novel feature of the model is the specification of the eastern boundary conditions. This is an upwelling favourable region with a quasi-permanent southward flowing coastal jet, which is fed by the eastern branch of the Canary Current. The corresponding boundary conditions are non-zero normal flux and constant potential vorticity, the latter being consistent with the generation of anticyclonic vorticity by the coastal jet. We examine the sensitivity of the model to the eastern boundary conditions and compare the results with recent observations for the region.
Highlights
The eastern region of the North Atlantic Subtropical Gyre (NASG) shows an anticyclonic loop formed by the Azores Current (AC), the Canary
Clearly illustrate the influence of the eastern boundary conditions in the eastern subtropical gyre, which makes it possible to reproduce a number of observational features
Despite the simplicity of the model, we find that the chosen specification of the eastern boundary conditions provides qualitative, and to a certain extent quantitative, features of the eastern boundary current regime which show similarities with the observations
Summary
The eastern region of the North Atlantic Subtropical Gyre (NASG) shows an anticyclonic loop formed by the Azores Current (AC), the CanaryCurrent (CC), and the North Equatorial Current (NEC). North of 30oN and off the African continental platform there is permanent onshore geostrophic transport of about 1-2 Sv. North of 30oN and off the African continental platform there is permanent onshore geostrophic transport of about 1-2 Sv This water flux necessarily recirculates south close to the coast until it rejoins the interior deep ocean between 20 and 25oN (Stramma, 1984; Stramma and Siedler, 1988), in what we may call the eastern branch of the CC. This eastern branch is so narrow that it does not show up in Stramma (1984) and Stramma and Siedler (1988) maps, which where obtained from deep ocean data. This eastern branch is so narrow that it does not show up in Stramma (1984) and Stramma and Siedler (1988) maps, which where obtained from deep ocean data. Arhan et al (1994), have inferred an eastward transport of about 11 Sv into the eastern boundary layer and at densities lower than 27.25 sigma-theta, which appears to feed southward alongshore currents
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
