Rainfall
Also called: Rain · Topic: Water in the Atmosphere: Humidity, Condensation, Clouds and Precipitation · NCERT: Class 11, Ch 10 "Water in the Atmosphere"
Meaning
Rainfall is precipitation that reaches the ground as liquid water drops. Precipitation means any moisture that falls from clouds. Rain falls when cloud droplets grow too heavy for the air to hold up. By how the air is lifted and cooled, rainfall is of three types:
- Convectional: from rising heated air.
- Orographic: from air forced up a mountain.
- Cyclonic (frontal): from warm air rising over cold air along fronts.
Rainfall is measured with a rain gauge, in millimetres or centimetres.
Example
The south-west monsoon winds rise up the windward Western Ghats and give Mumbai about 200–250 cm of rain. The leeward Deccan, for example around Pune, lies in a rain shadow, a dry area on the sheltered side of a mountain, and gets much less.
Don't confuse with
- Precipitation: the wider term. It also includes snow, sleet and hail. Rainfall is only the liquid form.