They are caused by the Coriolis force acting on currents driven by large scale wind patterns.
Latif and Barnett connected variations in climate to interactions between the Aleutian low-pressure system and one of these. Henry Stommel explained the dynamics of their boundaries. They can form Taylor caps near the surface. Circulation is often studied using a "double" model of these. Subtropical ones have a thicker thermocline than tropical ones. They intensify on their western boundary as can be seen in the Kuroshio boundary. One of these in the North Pacific creates an enormous garbage patch. Ekman transport moves water into their centers. They are caused by the Coriolis force acting on currents driven by large scale wind patterns. FTP, name these large rotating currents in oceans.
Latif and Barnett connected variations in climate to interactions between the Aleutian low-pressure system and one of these.
{gyres} [prompt on {oceanic currents} before mentioned]