What is the term for the circuit of mid-latitude currents around the periphery of an ocean basin?

• A. Gyre
• B. Ekman Spiral
• C. ENSO
• D. El Nino

Answer: (A)

Circulation around the edge of an ocean basin forming a large, circular pattern of surface currents is called a gyre. In mid-latitudes, winds push surface water and the Coriolis effect deflects it, causing the water to loop around the basin’s perimeter. This creates a clockwise gyre in the Northern Hemisphere and a counterclockwise gyre in the Southern Hemisphere, with warm water moving poleward along the western boundary and returning equatorward along the eastern boundary. The term captures this broad, basin-wide circular flow, seen in the North Atlantic and North Pacific, among others. By contrast, the Ekman Spiral describes how wind-driven flow changes with depth, not the overall circular current pattern, and ENSO and El Niño are climate phenomena related to temperature and wind anomalies in the equatorial Pacific, not the general mid-latitude gyre.