Upwelling
The major upwellings in the ocean are associated with the divergence of currents that bring deeper, colder, nutrient rich waters to the surface. There are at least five types of upwelling: coastal upwelling, large-scale wind-driven upwelling in the ocean interior, upwelling associated with eddies, topographically-associated upwelling, and broad-diffusive upwelling in the ocean interior.
Haida Eddies
Haida eddies possess common physical characteristics that are dependent on the attributes of the water that is being transported, and how that influences the overall structure. Haida eddies are characterized as relatively long-lived, transient (departure from the average ocean current along the coast), medium-sized (mesoscale) ocean eddies that rotate clockwise (anti-cyclonic), and possess a warm, less-saline core, relative to the surrounding waters. These warm waters within the eddy are attributed to the baroclinic clockwise motion that results in a piling up of water near the center, and a downward displacement of surface water to depth (downwelling). This phenomenon is referred to as Ekman pumping, resulting from a conservation of mass, vertical velocity, and the Coriolis force. Downwelling of water from convergence produces what is called 'dynamic height anomalies' between the center and the surrounding waters. The anomaly is calculated by taking the difference between the surface of interest, for example the middle of a Haida eddy, and a reference point (in oceanography it is in reference to the geopotential surface, or the geoid). Haida eddies are capable of producing dynamic height anomalies between the center and the surrounding waters of 0.12-0.35 m.