Explanation:

As we all know, the density of sea water varies from place to place according to its
temperature and proportion of salinity. The density increases with an increase in salinity
and decreases with a decrease in salinity. But when the temperature increases, density
decreases and when the temperature decreases density increases.
This increase and decrease in density due to the differences in temperature and salinity
causes the water to move from one place to another.
Earth’s rotation causes Coriolis force which deflects the air to its right in the northern
hemisphere and to its left in the southern hemisphere-Ferrel’s Law.
Similarly, oceans water also affected by the Coriolis force and follows the Ferrel’s Law.
Hence, ocean currents in the northern hemisphere move in a clockwise (towards right)
direction and ocean currents in southern hemisphere moves in an anti-clockwise (towards
left) direction.
The winds like trade winds and westerlies drive the ocean water in a steady flow in front of
them. When the direction of the winds changes, the direction of the current also gets
changed.