Two interesting phenomena off the West African coast seen on 9th Oct 2007.

There are several Von Karman vortex streets south west of the Canary Islands and I noted lesser vortices south west of The Cape Verde Islands.
Also note a 'stone in pond' ripple effect heading from the African coast towards the Cape Verde Islands.  These are 'gravity waves'.
See http://en.wikipedia.org/wiki/Gravity_wave
[MSG Data © EUMETSAT 2007] (352Kb). Processed with David Taylor's MSG DataManager and GeoSatSignal. 
I have also posted a short animation of the effect (497Kb)   Right Click on this link & 'Save Link As' or 'Save Target As' to download