Transcript Wind:

Wind Notes:
Remember …
• Air has mass and takes up space.
• Air pressure – the mass of the air being
pulled down on an area of the earth’s
surface.
• It pushes in all directions - it does not
crush objects
Factors that affect Air Pressure:
1. Temperature
2. The amount of air above it
3. How fast it is moving
Wind:
Horizontal movement of air (fluid)
from an area of high pressure to
low pressure
High Pressure
Low Pressure
example
A
A to B movement= NO ENERGY (wind)
B to A movement= ENERGY (fan)
B
Wind facts:
1) The greater the pressure
difference, (temp difference)
The greater the WIND!
2) Described by original direction and
speed
ex: Northeastern wind at 50mph
Measurement of Wind:
1) Wind vane- measures wind direction
2) Anemometer:
measures wind speed
3) Wind-chill factor: increased cooling caused
by the wind
* cool breeze blowing by skin
removes heat
Two Types:
1) Local Winds
2)Planetary (or Global)
Winds
Local Wind:
effect small areas (beach, lake)
1) SEA BREEZE
P
P
land
water
Blue = Cool
Red = Warm
SEA BREEZE
* Land heats faster than the water
Air above land heats faster
• Warm air rises creating LOWER
pressure over land
• High Pressure over water
COOL air moves TOWARD
LAND= CLOCKWISE
2).Land Breeze
P
P
land
water
LAND BREEZE
• Land cools faster than
water
• Pattern of circulation is
reversed
• Air moves toward water
»COUNTERCLOCKWISE
Coriolis Force/Effect:
• Due to Earth’s rotation,
– Winds in Northern Hemisphere curve to the
RIGHT = CLOCKWISE
– Winds in Southern Hemisphere curve to
The LEFT= COUNTERCLOCKWISE
NH
equator
SH
PLANETARY/GLOBAL WINDS
*Caused by: Uneven heating of
Earth’s surface
*Warm air rises at the equator and
*Cold air sinks at the poles
Major Wind Systems
• 1) Trade Winds:- steady winds blowing to the
southwest. Ships used them (“traders”) to travel
with goods.
• 2) Prevailing Westerlies:-blow from
southwest to northeast. Moves WEATHER
across the United States and Canada
• 3) Polar Easterlies:due to the Coriolis effect,
winds at North pole rotate clockwise.
Winds at the South pole rotate
counterclockwise
4) Jet Stream:- fast moving streams of air
higher than other wind systems.
Narrow and Strong
Pilots use them
• 5) Doldrums:- windless zone at the
equator. (remember CONVECTION)
• 6) Horse Latitudes:- windless zone at
30 North and 30 south latitudes
(Tropic of Cancer/Tropic of Capricorn)
Diagram of winds