Question

What causes differential heating of land and water?

Answer 1

Differential heating refers to the difference in how land and water surfaces absorb heat. Heat absorbed by the oceans is distributed, through mixing, over a greater depth than is the heat absorbed by land surfaces. So in the summer, when the amount of solar radiation is highest, the difference between the land and ocean temperatures is highest. This causes the air over the land to heat up and expand causing it to become less dense and rise. This rising air is then replaced with neighboring moisture rich air from over the oceans surface .
The degree and direction of the differential heating between land and sea is determined by the amount of solar energy reaching the earths surface. In summer the difference is greatest with the land surface warmer than the oceans causing surface winds to move onshore. In the winter the ocean surface is warmer than the land, but the effect on winds due to this difference is less than in summer. In this case the surface winds are reversed and less intense.
Diurnal variability of differential heating results in a "sea breeze". When the differential heating persists over several months, as in winter and summer, strong prevailing winds are produced. These persistant prevailing winds are characteristic of a monsoon climate.
Since the Indian Ocean is bounded to the north by the largest land mass on the planet, the effects of differential heating are intense.