Transcript What causes Winds? - Mona Shores Blogs

Key Idea #15
The warming of the Earth by the sun
produces winds and ocean currents.
What causes winds?
http://www.weatherquestions.com/wind.jpg
Air will rise if it is warmer
than the surrounding air.
The upward movement of
warm air and the
downward movement of
cool air form convection
currents.
If cool air is present, warm
air will rise to great heights
and eventually cool.
Cool air holds less water
vapor than warm air.
Local Winds
blow over short distances.
form when no winds are blowing from farther away.
are caused by the unequal heating of the Earth’s surface
within a small area.
Sea (Lake) Breeze
Land Breeze
Sea (Lake) Breeze
Unequal heating often
occurs on land that is next
to a large body of water.
Land heats up more quickly
than water.
The warmer air over the
land expands and rises,
creating a low pressure area.
Cooler air blows inland from
the water and moves
underneath the warmer air
creating a wind known as a
sea or lake breeze.
Land Breeze
At night land cools more quickly than water, so the air over
the land becomes cooler than the air over the water.
As the warmer air over the water rises, cooler air moves
from the land to take its place.
This flow of air from land to a body of water is called a land
breeze.
Uneven Heating of the Earth
Global Winds
are the movement of air between the equator and the poles
caused by the unequal heating of the Earth’s surface.
blow from specific directions over long distances.
Coriolis Effect
is the way Earth’s
rotation makes winds
curve.
In the Northern
Hemisphere all global
winds gradually turn to
the right.
In the Southern
Hemisphere all global
winds gradually turn to
the left.
An ocean current is
the movement of
ocean water.
made up of hot or
cold water.
Note:
The movement of
ocean water is similar
to the movement of
warm and cold air in
the atmosphere.
Convection currents move warm water through the oceans.
Convection in oceans occur because
the ocean waters heat up becoming
less dense.
The warm water moves above the
cooler water, and give off its heat to
the surrounding environment.
As the water cools, it begins to sink,
and the process begins again.
Convection results in the continual
circulation of ocean water on a
global scale.
FYI: How is Wind Measured?
Wind speed is measured using an
anemometer.
The force of the wind causes the
cups to spin on an axle which
activates a speedometer.
Wind direction is measured using a
wind vane.
The arrow points in the direction
the wind is blowing from.
FYI: Beaufort Wind Scale