Winds blowing over an ocean basin are the primary cause of ocean gyres and western boundary currents.
Surface winds drive Ekman transport that converge water in the centre of basins, causing sea surface gradients that drive the gyres. Changes in Coriolis with latitude and frictional effects mean that these gyres are asymmetric and form western boundary currents.
Welcome to the Stommel Basin Simulator. This interactive tool models ocean circulation in a simplified rectangular basin driven by wind stress.
The model solves depth-averaged shallow water equations on a C-grid using a simplified finite-difference scheme.
The first two equations are an expression of Newton's law F = ma. They say that the acceleration of water relates to pressure forces (related to sea surface height gradients), wind forces, and frictional forces (at boundaries and internally).
The third equation tells us that volume is conserved: water entering a region must be balanced by water exiting some other region.
The equations represent the combined effects of Ekman and geostrophic currents.
Critically, this app shows us that: