conditions of precipitation, their types and mechanism of orographic precipitation

1. Necessary Conditions
Cooling of
air (Lifting
mechanism of
air)
Condensation
and cloud
formation
An
accumulation
of moisture
The growth of
cloud
droplets
Mechanism of Precipitation

2. 1. Convectional Lifting:
• Heating of earth’s surface
causes air to rise rapidly
• Maritime air masses cross onto
land, experience surface heating
• Create low pressure as the air
rises, air cools
• Moisture condenses into clouds
and precipitation.
Mechanism of Precipitation
Air Lifting Mechanism
2. Frontal Wedging:
• When two contrasting
temperatures are there, air
masses and densities collides
• Precipitation occur at the
surface of contact.
• Warm air rises above cold air

3. 3. Orographic Mechanism
4. Convergence
• It occurs when mountains act
as a barrier to air flow
• Adiabatic cooling generate
clouds and precipitation
occurs at windward side
• Many of wettest places are
located on windward
mountain slopes.
•It occurs by collision of contrasting
large air mass which forces air to rise
vertically.
•Uplifting of these wind coming from
different direction result in cloud
formation.

4. Mechanism of Precipitation
Orographic and Rain Shadow Mechanism
Windward
Mountain Slope Leeward
Mountain Slope
Wet areas are
mostly present on
windward side
Air becomes warmer,
dry and humidity rate
drop
•High temperature on leeward is result
of latent heat release during
condensation at top of mountain.