Topic: Salient features of world’s physical geography. Important Geophysical phenomena such as earthquakes, Tsunami, Volcanic activity, cyclone etc.,
2. What aspects are responsible for the origin and modification of ocean currents? Explain with examples how they affect the climate of surrounding regions.(250 words)
Reference: physical geography by Savindra Singh
Why this question:
The question is from the static portions of GS paper I , theme physical geography of the world.
Key demand of the question:
One must discuss factors that are responsible for the origin and modification of ocean currents and their effect on the climate of the surrounding regions.
Explain – Clarify the topic by giving a detailed account as to how and why it occurred, or what is the particular context. You must be defining key terms where ever appropriate, and substantiate with relevant associated facts.
Structure of the answer:
Briefly define what ocean currents are.
First of all, bring out factors which are responsible for the origin and modification of the ocean currents and elaborate them briefly; origin, Other factors – Accumulation of water on east coasts leads to gravity induced movements down the slope. Expansion due to heat – Even though water is considered practically incompressible, minor expansion due to excess solar heat in equatorial regions causes a slight gradient and water tends to flow down the slope. Modification – Wind, Coast line and inundation, large river discharge, presence of partially enclosed seas. Periodic reversals due to heating and accumulation can also cause modification such as in case of ElNino current caused by a stronger counter equatorial current. Coriolis force etc.
Then, with examples, elaborate how ocean currents determine the climate of surrounding regions.
Conclude with significance.