The circulation of the deep ocean is driven by the increase in density of surface water due to changes in its temperature and/or salinity. A major mechanism whereby the density of surface waters at high latitudes increases is by

Cooling

Explanation:

In the higher latitudinal regions, the temperature remains much colder in comparison to the low latitudinal region. Due to this, there occurs rapid cooling of the seawater, and the surface water also remains moderately cool, along with the increasing salt concentration, the density of the seawater in this region is high.

The rate of cooling is relatively high here in comparison to the rate of evaporation or heating. So the cooling is one of the major mechanisms in the high latitude regions that are responsible for the formation of denser water.

net evaporation

Explanation: