Seasonal and interannual variability of the Canary Current

Seasonal and interannual variability of the Canary Current on its passage t hrough the Canary archipelago and between 20-35 degreesN and 10-20 degreesN are studied with long series of historical tide gauge, sea surface tempera ture and hydrographic data. The variability of winds is more seasonal in th e north of the area, where they are weak and perpendicular to the coast in winter, than in the south, where winds are roughly parallel to shore all ye ar though strongest in summer. Temperature and salinity data maps show a cu rved structure indicative of the subtropical gyre, which varies seasonally from North to South and from the open ocean to the coast. Dynamic height an alyses show this seasonal variation of the gyre to depths of 200 m and indi cate the existence of a meander-like diversion around the Canary Islands. T he sea level in the Canary Islands also indicates a strong seasonal variati on of the north Atlantic subtropical gyre. The southward geostrophic surfac e flow, derived from sea surface slope, was strongest during spring and sum mer at the eastern islands while it was strongest in winter at the outermos t islands. The spatially averaged flow between the innermost and outermost islands shows the strongest southward flow in winter. Interannual variation of the flow between these islands, investigated during two periods, 1950-1 956 and 1960-1973, reveals a mainly southward flow, although several show a northward tendency. The maximum equatorward velocity of the current in bot h periods is around 5 cm s(-1), indicating a weak current.