Equatorial Currents

(in Russian, trade-wind currents), surface currents of the world oceans in the tropical and equatorial latitudes of the northern and southern hemispheres, caused by the trade winds. The regularity of the trade winds makes the equatorial currents very stable. The velocity of the currents is 0.2–1.0 m per sec, diminishing rapidly with depth; the flow rate is up to 45 million cu m per sec.

In the Atlantic and Pacific oceans the equatorial currents occur in the form of two broad streams separated by the narrow Equatorial Countercurrent, which is located at 3°-10° N lat. in the area where the northeasterly and southeasterly trade winds converge. In the Indian Ocean, owing to the monsoon circulation, the North Equatorial Current is observed only during the winter; in the summer it is replaced by monsoon currents flowing in the opposite direction. The Equatorial Countercurrent is at 2°-10° S lat. Flowing from the east, the equatorial currents carry water arriving from higher latitudes; therefore, the temperature of their waters rises from east to west, with temperatures of 20°-25° C in the east and 28°-29° in the west; salinity also increases, from 34.5 to 37.3 ‰ (per mill). In the western parts of the oceans, the equatorial currents give rise to powerful currents that move toward the poles: the Antilles and Brazil currents in the Atlantic, the Taiwan and East Australian currents in the Pacific, and the Southwest Monsoon Drift (winter only) and Mozambique Current in the Indian Ocean.