Secular Variability of the Upwelling at the Canaries Latitude: An Instrumental Approach

Abstract

Upwelling is a process in which sea water from intermediate depths rises toward the surface as a response to the wind friction along the west coast of continents. Upwelled water is rich in nutrients, creating areas of paramount importance for fisheries. A long-standing hypothesis contends that upwelling might be intensified because of global warming, but due to the impediments to quantify the upwelling intensity for long periods, the scientific community still debates whether the upwelling is changing. We have used historical wind observations taken aboard ships sailing along the coast of Northwest Africa to show that there, during the last two centuries, upwelling has not increased but it has oscillated synchronically with the temperature of the North Atlantic.