Write short notes on:
- Convectional rainfall
- Orographic rainfall
- Cyclonic rainfall
Convectional rainfall : When the temperatures are high, the air gets heated. Warm air rises higher into the atmosphere; it then expands and spreads at the top. Ascending currents of hot and humid air results in condensation and in the formation of cumulo- nimbus clouds of great vertical extent. Such clouds give heavy rainfall. Convectional rainfall generally occurs in the equatorial regions where the temperature and rate of evaporation is quite high.
Orographic rainfall : This type of rainfall is also known as relief rainfall. When moisture bearing winds strike a mountain range, it is forced to ascend or go up. As the wind rises up the mountains, it cools down to its saturation point bringing rainfall on the windward side of the mountains. These winds when they reach the leeward side of the mountains,are devoid of moisture and hence places located on the leeward side of the mountains get scanty rainfall.
Cyclonic or Frontal rain : This type of rainfall occurs when warm and cold air meets each other. Since warm air is lighter, it rises above the cold air. The rising air is then cooled beyond the saturation point resulting in heavy rainfall. Such rainfall lasts only for few hours. Rainfall is very heavy in the tropical cyclones.