Atlantic Ocean Leakage/Rings, which brings salty Indian Ocean waters into the South Atlantic, and the "Atmospheric Bridge", which evaporates subtropical Atlantic waters and exports it to the Pacific. The Atlantic Ocean consists of four major, upper water masses with distinct temperature and salinity. The Atlantic Subarctic Upper Water in the northern-most North Atlantic is the source for Subarctic Intermediate Water and North Atlantic Intermediate Water. North Atlantic Central Water can be divided into the Eastern and Western North Atlantic central Water since the western part is strongly affected by the Gulf Stream and therefore the upper layer is closer to underlying fresher
South Equatorial Current is driven directly by the trade winds which blow from east to west. In the Indian Ocean, the westward-flowing South Equatorial Current is well-developed only south of the equator. Directly on the equator, the winds reverse twice a year due to the monsoons, and so the surface current can be either eastward or westward. South Equatorial Current Ocean current in the Pacific, Atlantic, and Indian Ocean that flows east-to-west between the equator and about 20 degrees south. In the Pacific and Atlantic Oceans, it extends across the equator to about 5 degrees north. Within the southern hemisphere, the South Equatorial