Download Wind - Mr Young`s Geography Blog

Wind
What is wind?
• Wind is air in motion.
• It is produced by the
uneven heating of the
Earth’s surface by the sun.
• Since the Earth’s surface is
made of various land and
water formations, it
absorbs the sun’s radiation
unevenly.
What causes wind to blow?
• As the sun warms the Earth’s surface, the
atmosphere warms too.
• Some parts of the Earth receive direct rays from
the sun all year and are always warm.
• Other places receive indirect rays, so the climate is
colder.
• Warm air, which weighs less than cold air, rises.
• Then cool air moves in replacing the warm air.
• This movement of air is what makes wind blow.
Atmospheric pressure
• Low atmospheric pressure = areas where hot
air is rising.
• High atmospheric pressure = areas where cool
air descends toward Earth.
• Air moves:
high pressure areas
low pressure areas.
Facts about wind
• Winds are named after the direction from
which they blow.
Facts about wind
• The wind that is most frequent in an area is
called the prevailing wind.
• What is Ireland’s prevailing wind?
Facts about wind
• Winds that blow from the equator to the
poles are warm winds.
• Winds that blow from the poles towards the
equator are cold winds.
HP
LP
HP
LP
60ºN
30ºN
Equator
Coriolis Effect
Earth spins on its axis
from west to east.
This changes the
direction of winds:
•Winds are deflected
to the right of their
direction in the
northern hemisphere.
•Winds are directed to
the left of their
direction in the
southern hemisphere.