Pub. date: 2008 | Online Pub. Date: April 25, 2008 | DOI: 10.4135/9781412963893 | Print ISBN: 9781412958783 | Online ISBN: 9781412963893| Publisher:SAGE Publications, Inc.About this encyclopedia
Western Boundary Currents
Alexander Boris Polonsky
WESTERN BOUNDARY CURRENTS are intense jet currents at the western periphery of large-scale oceanic gyres in the World Ocean. As was shown in the pioneer paper of Henry Stommel in 1948, they are the result of two causes: the so-called β-effect (this term has arisen from traditional representation of Corio-lis force, f , in the following form: f = f 0 + βy, where f 0 is a Coriolis parameter at a definite latitude; in other words, the β-effect is to the result of the spherical form of the Earth turning around its axis), and low conservation of absolute vortex for the oceanic motions. Oceanic gyres are forced by horizontally inhomo-geneous large-scale wind fields (or wind vorticity). For instance, in the North Atlantic Ocean, anticy-clonic subtropical gyre is situated under northeastern trade wind and midlatitude westerly wind as a result of clockwise wind vorticity, whereas north tropical cyclonic gyre is ...