4. This is called the
PRESSURE
GRADIENT it is the
spacing of the isobars
with indicates the
pressure changes
occurring over the given
distance.
Strong winds also occur in low
latitude due to stronger heating
and steeper pressure gradients.
HURRICANES and
TORNADOES are both tropical
phenomena.
WIND STRENGTH
Depends on the
different in pressure
between the high
pressure system, and
the distance between
them.
ISOBARS are line connecting places
of equal pressure
5.
6. High
In the north, winds
blow anti clockwise into
a low pressure system.
In the south, they blow
clockwise.
Low
Actual Wind
Which blows,
are diverted by
coriolis
The earth’s rotation diverts
this wind direction laterally.
This force is called the
CORIOLIS FORCE.
The coriolis force diverts
wind the right in the
northern hemisphere; to the
left in the south.
The effect is stronger at high
altitude where ground level
friction is less significant.
7. Strong polar winds due to
low friction.
Beach windbreaks reduce
wind speed by increasing
friction.
9. Local Winds
Winds we frequency encounter and these blow in any direction.
Produced on a local scale by processes of heating and cooling of lower
air.
10. Two Categories of Local Winds
Katabatic Wind
a category includes local winds in hilly or mountainous region,
where on clear and calm nights, heat is rapidly lost by grounds
radiation.
Katabatic Wind usually felt
on the great ice caps of
Greenland and Antartica
12. Prevailing Winds
• Winds that blow from the same direction and most often travel
long distance.
• Also known as Permanent Winds or Planetary Wnds.
• It is sub divided in to the trade winds, anti trade winds, and polar
winds.
13. Two factors that Affect the Direction of
Prevailing Winds
Unequal Heating of the Earth’s surface.
Earth’s Rotation
14. Periodic Winds
• Are also known as Seasonal winds or Monsoons.
• They blow from water bodies to land.
