Surface currents
Topic: Movements of Ocean Water: Waves, Tides and Currents · NCERT: Class 11, Ch 13 "Movements of Ocean Water"
Meaning
Surface currents are ocean currents in the upper 400 m of the sea. They hold about 10% of all ocean water. Wind mainly drives them, so they follow the pattern of the planetary winds (the large, steady wind belts such as the trade winds and westerlies). They are the fastest currents, often up to 5 knots. They carry heat towards the poles and shape coastal climates.
Example
The Somali Current off the coast of Somalia, in the Arabian Sea, flows north in summer, when it is one of the fastest currents. It flows south in winter. It reverses because it follows the monsoon winds.
Don't confuse with
- Deep water currents: these move the other 90% of ocean water. They are slow and driven by differences in density, not by wind.
Related concepts
- Ocean current
- Forces driving ocean currents
- Ekman transport
- Gyre
- Deep water currents
- Warm current
- Cold current