Westseitenströmen

Westseitenströmen is a term used in marine science to describe persistent currents that run along the western boundary of a sea or ocean basin. The concept refers to a class of intensified, relatively narrow flows that are part of larger gyre circulation and are guided by the coastline on the western side of the basin.

The formation of Westseitenströmen is driven by a combination of wind forcing, the Coriolis effect, and the need to conserve angular momentum in a rotating system. In many basins with subtropical gyres, winds push water away from the interior, producing a poleward flow along the western boundary that is typically stronger and deeper than the surrounding water. These currents are often fast and persistent, capable of transporting heat, salt, and biological material over long distances.

Characteristics of Westseitenströmen include relatively high flow speeds for boundary currents, strong vertical shear, and notable seasonal and interannual variability tied to prevailing wind patterns and large-scale climate oscillations. They are monitored through satellite altimetry, in-situ instruments such as ADCPs, drifters, and hydrographic sections, which help to quantify their speed, depth, and variability.

Examples commonly associated with the broader concept of Westseitenströmen are the Gulf Stream in the North Atlantic and the Kuroshio in the North Pacific, both of which are major western boundary currents. These flows play a crucial role in regional climate by transporting heat poleward, influence nutrient transport and marine ecosystems, and affect regional weather and coastal climates.

See also: Western boundary current, Ekman transport, Sverdrup transport, ocean circulation.