MONSOONS

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MONSOONS

• By Adrienne Dewsberry

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Table of Contents

• An Introduction to Monsoons
• Formation of Monsoons
• Diagrams of Monsoon Formation
• Location of Monsoons
• Appearance of Monsoons
• Maps
• How Monsoons Act
• Effects of Monsoons
• Social and Economical Impacts
• Characteristics
• History of Monsoons
• Sources

• Page 3
• Page 4 and 5
• Page 6
• Page 7
• Page 7
• Page 8 and 9
• Page 10
• Page 11
• Page 11
• Page 12
• Page 13
• Page 14

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An Introduction to Monsoons

• Monsoons comes from the Arabian word Mausin
  which means the season of the wind. It was
  given this name because the winds over the Indian
  Ocean and areas near by are blowing from the
  southwest for part of the year and from the
  northeast during the rest of the year. Areas in
  this region dont have winter, spring, summer and
  fall but they have a wet season (June to
  September) and a dry season (September to
  March). During the wet season there is lots of
  rain and not too many dry days but during the dry
  season there will be hardly any precipitation. To
  countries such as India and those in southern
  Asia count on these monsoons to bring them enough
  precipitation to last them the year. Monsoons may
  seem destructive but are very important to the
  everyday lives of some people.

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Formation of Monsoons
Monsoons are caused by many things. The tilt of
the Earth in relation to the sun is the main
thing that causes monsoons to form. Also the
differences in temperature of the land and the
ocean (or sea), the Coriolis effect and water are
very important to the creation of
monsoons. Upper-level winds such as jet streams
help to influence the cold and warm air masses on
the Earth. In the summer (wet season) in
southeast Asia, India and surrounding areas the
land is warmer then the oceans and seas. Over the
land the hot air rises and cool air from the
ocean comes in to replace it. As the cool air
comes in of the oceans it brings along moisture
which is then released over the land causing
heavy and long lasting rain. This goes on from
about June until September every year. During
this period, the areas affected by the monsoons
receive most, it not all, of their annual rain
fall.
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Formation of Monsoons
Between September and March is the winter, or
dry, season. During this time the circulation
reverses its self. Now the oceans and seas are
warmer then the surrounding land and as the warm
air off the ocean rises, the cool land air
replaces it. Therefore the moisture is carried
out to sea. At this time places like the northern
Australia, the eastern coast of India and Sri
Lanka are having their rainy season, opposite to
south-eastern Asia and west and central India
which are having their dry season. During this
time the Himalaya mountains act as a wall to cool
air and rain coming from the north of Asia. This
makes areas to the south hot and dry until the
next rainy season. It is impossible the predict
when monsoons will occur, how long they will last
and how much precipitation they will bring even
though they occur every year and have for
thousands of years. They are just so inconstant
and rely on constantly changing factors (wind,
temperature, etc.) that know one can yet know
exactly when they will come that year. In the
future this may become possible thanks to
generations to come.
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Diagrams of Monsoon formation
Strong Solar Radiation
Low pressure
High pressure cooler ocean
Hot land surface
Weak Solar Radiation
High Pressure
Low-pressure warmer ocean
Cold land surface
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Location of Monsoons
Monsoons occur near and around the equator where
the suns heat is strongest. Many countries such
as Australia, India and southern Asia receive
these torrential rains and long dry periods.
Other areas that are affected include the Gulf
coast of the U.S., central Europe and other
places near the equator, the Gulf Coast of the
U.S., central Europe, and other areas. (See the
maps on the next 2 slides to see all areas
affected by monsoons)
Appearance of Monsoons
Monsoons dont appear to look much like
anything. They are just types of weather that
bring very rainy weather during the summer months
and hot dry weather during the winter months. In
the summer months there will be lots of rain
which often causes flooding and very severe
damages. The sinter months bring heat and almost
no rain. During this time droughts can occur.
Other than that there is no way to describe the
appearance of monsoons.
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World Climates
In general, the countries with tropical weather
(in pink colours on this map) are affected by
monsoons
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Monsoons of the World
This is a map that shows what areas of the world
are affected by which monsoon since there are
many.
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How Monsoons Act
It is hard to describe how monsoons act since
they are very unpredictable. However the rainy
monsoons are like sheets of water coming in and
last for long periods of time where as the dry
monsoons are like saunas since they bring hardly
any rain, cool weather or moisture of any kind.
Monsoons act like clockwork though since the come
every year it is just hard to know exactly when.
Monsoons are very interesting weather patterns
and scientists are still trying to determine a
regular pattern or way to predict how they will
act that particular year.
A photo of a forest in a monsoons affected area
during the rainy season. Appears as a sheet of
rain.
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Effects of Monsoons
Monsoons have both positive and negative
effects. The dry monsoons (winter monsoons) bring
dry, hot weather and even droughts that causes
major problems for the people in the area. When
the wet monsoons (summer monsoons) come they
bring an end to the drought but bring floods and
destructive rains. Then when the dry monsoons
return again they bring an end to the torrential
and devastating rains but once again bring dry,
hot weather and droughts. The two monsoon seasons
relive each other for a little while but then
bring their own problems.
Social and Economical Impacts
Monsoons help and ruin farms in the areas they
affect. They bring the rains to keep the plants
growing in other wise dry, hot areas but
sometimes bring to much. They flood homes,
villages, towns and countries and cause horrible
damages that will need costly repairs. In the dry
season the farms can not produce what they need
and are ruined. Also it causes drought making
healthy, drinkable water hard to come by. Most of
the countries that are affected by these monsoons
are poorer countries and can not always afford
the costs related to the damages of monsoons or
can pay for ways to limit the amount of damages
done.
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Characteristics
Summer monsoons often cause much flooding in the
areas affected by them. Monsoons are also very
regular. About half the year in affected areas
the summer monsoons are there, known by their
torrential rains, floods, and cooler weather. The
other half is spent in the winter monsoons, known
by their dry, hot weather, droughts and almost no
precipitation or cool weather. This is all
monsoons are like. Thunderstorms are possible
like in all areas but never snow save up in the
mountains since all the areas are in the tropics.
There are no real characteristics to monsoons
save rain for one and no rain (or hardly any) for
the other.
Flooding at a camp caused by monsoons in 1969
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History of Monsoons
Monsoons have been around longer then anyone
knows. They have always been a part of tropical
weather and will continue to be so for thousands
of years to come. Also, sailors have been using
the monsoon winds for centuries to sail across
places such as the Indian Ocean. Throughout the
years monsoons have caused many deaths by
drowning and even deaths related to droughts. The
history of monsoons is not very different then
the present monsoons or the future monsoons. The
main difference is the knowledge of people world
wide. Now we know more about them then we did
centuries ago and can work with and around them
since they can not be avoided. Before no one knew
what they were or if they were only occasional
but know we know generally when and where they
will happen though that may change since the
Earth and the land forms on it are constantly
changing.
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Sources

• Alan J. Hirsch. Nelson, Science 10,Canada
  THOMSON LEARNING,2001
• http//snrs.unl.edu/amet351/ogren/monsoons.html
• http//www.ace.mmu.ac.uk/eae/Weather/Older/Monsoon
  s.html
• http//www.kjc.gov.my/htdocs3/english/education/we
  ather/monsoon01.html
• http//www.erin.utoronto.ca/w3env100y/env/ENV100/
  sci/weather.htm
• http//en.wikipedia.org/wiki/Monsoon
• http//www.chs.k12.nf.ca/socstud/ssgrssroots/Monso
  ons/causes.html

Monsoon rain