1.1.3 Ocean Currents

Question 1

Surface currents

Answer 1

-Winds cause surface currents.
-Surface currents transfer heat from the equator to cooler regions.
—> E.g. warm water is transferred to Western Europe from the Caribbean by the Gulf Stream.

Question 2

Deep ocean currents

Answer 2

-Deep ocean currents are caused by differences in water density.
-Thermohaline circulation:
—> Water freezing in polar regions causes the surrounding water to become saltier and therefore denser.
—> The sinking of this dense water lets warm water flow in near the surface. This warm water will then cool and sink. And so, the cycle continues.

Question 3

Tropical climate zones

Answer 3

-Air rises where the Hadley cells from each hemisphere meet. This creates a belt of low pressure.
—> Conditions in these regions are high rainfall and high temperatures.

Question 4

Arid climate zones

Answer 4

-Air sinks where the Ferrel and Hadley circulation cells meet. This creates a belt of high pressure.
—> Conditions in these regions are high temperatures and low rainfall.
-Air from the Polar cells also sinks, creating high-pressure systems around the poles.
—> Conditions at the poles are low temperatures and low rainfall.