Compare and contrast convectional and orographic rainfall.

Basis

Conventional rainfall

Orographic rainfall

Occurrence

Occurs when moist air over the heated ground becomes warmer than the surroundings. The hot air rises expand, cools and condenses forming rain.

Occurs when moist windblown over the sea is forced to rise over a mountain or other elevation in its path.

Required conditions

It generally occurs in the tropics where temperature and evaporation are high.

It generally occurs in the upwind sides of the mountain ranges.

Extent of rain

It generally results in heavy rainfall accompanied by thunder and lightning.

The leeward side of the mountain gets very less rainfall because of the lack of moisture in the clouds.

Locations

Equatorial regions and the interiors of continents experience rainfall.

High-pressure belt to the sub-polar low-pressure mountainous regions experience the rainfall

Examples

Countries near the equator

Western Ghats