Comparer des méthodes

	Vitesse géostrophique	Transport d'Ekman
Domaine	Océanographie	Océanographie
Famille	Process / pipeline	Process / pipeline
Année d'origine	1942	1905
Auteur d'origine	Harald Sverdrup	Vagn Walfrid Ekman
Type	theoretical-method	theoretical-method
Source fondatrice	Sverdrup, H. U., Johnson, M. W., & Fleming, R. H. (1942). The Oceans: Their Physics, Chemistry, and General Biology. Prentice-Hall.	Ekman, V. W. (1905). On the influence of the Earth's rotation on ocean currents. Arkiv for Matematik, Astronomi och Fysik, 2(11), 1-52.
Alias	Geostrophic Current, Thermal Wind Equation	Ekman Spiral, Wind-driven Transport
Apparentées	3	3
Résumé	Geostrophic velocity is the current driven by balance between the pressure gradient force and the Coriolis force, derived from the thermal wind equation. In most of the ocean away from the equator and coastal boundaries, geostrophic balance is an excellent approximation to the actual flow. Developed by Harald Sverdrup and colleagues in the 1940s, geostrophic velocity calculation from hydrographic data enables estimation of ocean currents without direct current measurements.	Ekman transport is the net volume flux of water driven by wind stress balanced with Coriolis force in the surface boundary layer. Derived by Vagn Walfrid Ekman in 1905 from the principle that wind stress is transmitted through the water column in a spiral pattern, Ekman transport is responsible for coastal upwelling and important oceanographic transports. The theory links surface wind patterns directly to ocean circulation.