2. CONTENTS
• Wind
• Formation of wind
• Coriolis effect
• Types of winds: Global and Local wind
• Prevailing wind
• Location of Nepal
3. WIND RELATES TO AIR
• Air is the combination of all the gases –
that surrouds the earth atmosphere-
• -like carbon dioxide, argon, oxygen,
nitrogen, hydrogen and many more
• The movement of Air from place to place,
typically from a high-pressure area to a
low-pressure area i.e, wind
• Winds behave differently in many
different places and conditions around the
earth.
A 'wind' is simply the flow of a huge
amount of air, usually from a high
pressure-area to a low-pressure area.
Fig: layers of atmosphere
Fig: pressure and
wind direction
4. FORMATION OF WIND
• Begins with sun’s radiation- absorbed
differently on the earth’s surface and
heated differently –
• Due to cloud cover, water bodies,
vegetation, uneven surface like mountains,
valleys
• Variation of temperature on earth surfaces
• Air on surfaces with higher temperatures
-begin to rise - it is lighter, - creates low
atmospheric pressure
• Air on surfaces with cooler temperatures
sink - sinking creates higher atmospheric
pressure.
Fig: formation of wind
5. FORMATION OF WIND
• The behaviour when warm gases or liquids
moving upward and being replaced by
cooler particles is called Convection.
• The energy moving during convection is
called convectional current.
• Convection occurs in liquids and gases –
land breeze and sea breeze
• Sea breeze occurs at day time where as
land breeze at night time
Fig: formation of wind
Sea breeze
Land breeze
6. CORIOLIS EFFECT
• Wind appears to curve due to earth’s
rotation
• Northern hemisphere- wind curves to the
right
• Southern hemisphere- wind curve to the
right
8. TYPES OF WINDS
• Different classified winds like gentle
breeze, moderate winds, strong winds gale
winds(end up as tornadoes and hurricane)
• Types are: Local wind and Global wind
• Local wind- created as a result of scenery
such as mountains, vegetation, water
bodies and so on-
• ex:sea breezes and land breezes, and
mountain and valley breezes.
Slope
wind
9. TYPES OF WINDS
• Global wind - large air masses - created
mainly as a result of the earth’s rotation, the
shape of the earth and the sun’s heating
power.
• Types –
1. Polar easterlies
2. Prevailing westerlies
3. Tropical easterlies/ trade winds
4. Doldrums
10. TYPES OF WINDS
1. Polar easterlies- covers from 60° latitudes to the
north and south poles- wind blows from east to
west
2. Prevailing westerlies- covers 30° to 60° latitude
to the north and south - wind blows opposite
direction from west to east-Horse latitudes:Where
the Westerlies meet the trade winds at about 30
degrees (Jacksonville, Florida) is the Horse
latitudes, also Variables of Cancer, Subtropical
High, or Subtropical ridge. This is a region of
high pressure, dry air, and variable winds, and is
associated with deserts over land.
3. Trade wind- covers 0° to 30° latitude- wind
blows from east to west
4. Doldrums - 0° to 5° latitude to the north and south
of equatorial area- very low pressure area caused
by constant heating of the sun – calm area with
very little wind
11. PREVAILING WINDS
• Prevailing winds are the directions that
wind typically come from a location
• Distribute large amounts of solar
energy across the world
• Cause variety of precipitation like rain
or snow
12. LOCATION OF NEPAL
• The main latitude and longitude of
Nepal is 28° North and 84° East.
• small Asian country falls within the
Tropic of Cancer and the Arctic
Circle.
• The climatic condition of Nepal is
not typically a temperate one as the
country is located at the foothills of
the Himalayas.
13. CONCLUSION
• Hot/moist air rises up and cool/dry air
sinks down
• Low pressure due to hot air
• High pressure due to cool air
• Coriolis –curve wind due to earth’s
rotation
• Types local and global wind
