This document provides information about types of wind and wind mechanisms. It discusses three types of wind: permanent winds like trade winds and westerlies; seasonal winds that change direction with the seasons, like monsoons; and local winds that influence small areas, such as land and sea breezes. It also describes the mechanisms that drive wind circulation globally in three cells - the Hadley cell near the equator, the Ferrell cell in the mid-latitudes, and the polar cell near the poles. Air flows from high to low pressure in each cell, transporting heat around the world.

1. Geography
WIND
Group
• Prof. Mudassar
Shahzad Wahla
• I n t r o d u c t i o n
• Ty p e s & i t s
M e c h a n i s m
• 05
Group Members:
Mr. Shafeeq Ur Rehman (29)
Saud Ameer (11)
Misbah Hassan (49)
Taibah Najib (35)
Areej Iqbal (03)
Class:
BS URDU 4th (Evening)
Department:
Urdu & Oriental Languages
University of Sargodha,Sargodha

2. Wind
Content
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Content
Introductio
to Wind
Types of
Winds
Mechanism
of Wind
Wind
Circulation
on World
Map

3. Introduction of Wind
&
Types of Wind
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4. WIND:
 The movement of air.
From high pressure to low pressure.
Wind blow gently and also in strong form.
 Wind can broadly divided into three types:
The trade winds, westerlies and easterlies are the
permanent.
Blow seasonally, These winds change the direction in
different seasons.
E.g. Monsoons in Pakistan.
Permanent wind
Seasonal wind
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5. WIND:
These below only during a particular period of the day
or year in a small area.
E.g. Land or sea breeze.
Local wind
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Wind
Sea breeze Land breeze

6. Permanent Winds
Permanent winds
The winds that blow
constantly throughout
the year are called
permanent winds. They
also blow constantly in a
particular direction. They
are Trade winds known
as westerlies and
Easterlies.
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Wind

7. Wind
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Winds
its Types

8. Seasonal Winds
The winds that
change their direction
with onsets of different
seasons.
E.g.
o A Monsoon is a
type of seasonal wind
that seasonally
changes direction
between winter and
summer.
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Forecast of Monsoon 2011

9. Monsoon
A monsoon is a seasonal wind, found especially in Asia that reverses
direction between summer and winter and often brings heavy rains,
In the summer, a high pressure area lies over the Indian Ocean while a low exists
over the Asian Continent. The air masses move from the high pressure over the
ocean to the blow to the low over the continent, bringing moisture-laden air to
south Asia. During winter, the process is reserved and a low sits over the Indian
Ocean while a high lies over the Tibetan plateau so air flows down the Himalaya
and south to the ocean. The migration of trade winds westerlies also contributes
to the monsoons. Smaller monsoons take place in equatorial Africa, northern
Australia and in the southwestern United States.
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10. Year Actual onset Date Forecast onset Date
2005 7th June 10th June
2006 26th May 30th May
2007 28th May 24th May
2008 31st May 29th May
2009 23rd May 26th May
2010 31st May 30th May
PMD Data
 Over the years the Pakistan Meteorological Department (PMD) forecasts
Onset on Monsoon over Punjab & other provinces, which can seen on the
above given Table.
 The PMD has predicted that will hit Lahore on 31st May (Normal Date)
through forecast changes in June but as of now they are from on their earlier
decision that is the monsoon will enter Pakistan on the May 31.
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11. When will Monsoon start over Karachi?
The monsoon generally reaches Pakistan during the
first week of July while Karachi gets hit by monsoon
during the second week of July that is till July 7.
Following are the dates of monsoon onset in Karachi
during the last few years;
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Which large rainstorms are crucial for people in some
parts of the world?
India, Pakistan, and other nations in southern Asia are
great places to go to see monsoon rains. The region
depends on the water they bring. Parts of the
Southwestern United States also receive monsoon
rains. These rains break the summer heat. They also
provide water to desert plants. With winter rains and
summer rains, these deserts are more lush than many

12. Locall Winds
Local winds:
are winds that blow
over a limited
area. Local winds blow
between small low and
high pressure systems.
They are influenced
by local geography.
Nearness to an ocean,
lake, or mountain range
can affect local winds.
E.g. Land Breeze
&
Sea Breeze
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13. Land & Sea Breeze
The land and sea absorb and transfer heat differently.
• During the day the land heats up faster and becomes warmer than the sea.
• Therefore, over the land the air rises giving rise to a low pressure area, whereas the
sea is relatively cool and the pressure over the sea is relatively high.
Impact
• The Wind blows from the sea to the land as the sea breeze.
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14. Land & Sea Breeze
Situation in night
Reversal of
condition
takes places.
The land
loses heat
faster and is
cooler than
the sea.
Land breeze
usually occur
at night
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Land Breeze
Land breeze a local wind system
characterized by a flow from land to
water late at night.
CONCLUDE
Both are included by
differences that occur
between the heating or
cooling of the water
surface and the adjacent
land surface.

15. WIND MECHANISM
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16. Mechanism of Winds
 Winds acts as an active agent of erosion, especially in desert.
Sand Dunes
When the wind blow, it lifts and transports sand from one
place to another. When it stops blowing the blowing the sand
falls and gets
deposited in low hill. The structures created are called sand
dunes.
 When the grains of sand are very find
and light, wind can carry it over very
long distances are formed in this
process.
Mongolia Gobi desert in China
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17. • Mushroom Rocks, are another structures formed by wind.
• Wind blows Carries sand particle near the surface of earth.
These winds erode the lower section of the rock
more than the upper part.
Such Rocks have narrower base and wider top.
Mushrooms
Rocks
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18. Mechanism Of Wind
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19. WIND CIRCULAION ON
WORLD MAP
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20. The Wind circulation
Over the major parts of the Earth's
surface there are large-scale wind
circulations present. The Wind
circulation can be described as the
world-wide system of winds by
which the necessary transport of
heat from tropical to polar latitudes
is accomplished.
Wind Circulation on the World Map
Hadley
cell,
Ferrell cell Polar cell
In each hemisphere there are three cells:
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21. Wind
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Ferrell Cell
Ferrell Cell

22.  The first cell is called the Hadley cell.
At the equator, the ground intensely heated
by the sun.
 The largest cells extend from the equator
to between 30 and 40 degrees north and
south, and are named Hadley cells, after
English meteorologist George Hadley.
Hadley cell Circulation
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Hadley Cell

23. Ferrell cell Circulation
Ferrell
Cell
Ferrell
Cell
In the middle cells, which are known as
the Ferrell cells, air converges at low
altitudes to ascend along the boundaries
between cool polar air and the warm
subtropical air that generally occurs
between 60 and 70 degrees north and
south. This often occurs around the
latitude of the UK which gives us our
unsettled weather. The circulation within
the Ferrell cell is complicated by a return
flow of air at high altitudes towards the
tropics, where it joins sinking air from the
Hadley cell.
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24. Polar
cell
The smallest and weakest cells are the Polar cells, which extend
from between 60 and 70 degrees north and south, to the poles.
Air in these cells sinks over the highest latitudes and flows out
towards the lower latitudes at the surface.
.
At the poles, air is cooled and sinks towards the ground forming
high pressure, this known as the Polar high
The boundary between the warm and cold air is called the
Polar front
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25. Wind
Wind Circulation on the World Map
Coriolisn Effect
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26. Do you
have any
Questions .
Friendly
may ask?
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27. Wind
The End