Transcript 15.3 Winds - Cobb Learning

Please take out your Skills
WS and check your work
with a desk partner. Be
ready to ask any
questions on 15.2.
Objectives:
1. Explain the
relationship
between air
pressure and
wind direction.
2. Describe global
wind patterns.
3. Explain the
causes of local
wind patterns.
15.3 Global
Winds and
Local Winds
Copy into your
IAN!
Why Air Moves
 Wind-movement
of air caused by
differences in air pressure
 Greater pressure difference=faster wind
Air Rises at the Equator and
Sinks at the Poles
 Differences
in air pressure are generally
caused by unequal heating of the Earth.
 Equator




Receives more direct solar energy
Air is warmer and less dense
Warm air rises and creates low pressure
area
Warm air flows to poles
National geographic video
clip
 http://video.nationalgeographic.com/vid
eo/player/science/earth-sci/weather-101sci.html?referrer=epals
Air Rises at the Equator and
Air Sinks at the Poles, cont’d
 Poles




Air is cooler and more dense
Cold air sinks
Creates high pressure area
Cold air flows toward equator
 AIR
Moves from H to L !!!
Pressure Belts Are Found Every
30 Degrees
 Pressure
belts-bands of high pressure and
low pressure found every 30 latitude.
 Sinking air causes areas of high pressure
because sinking air presses down on the
air beneath it.
The Coriolis Effect
 Apparent
curving of
the path of winds
and ocean currents
due to the Earth’s
rotation.
 North- winds going
north curve east
 South- winds going
south curve west
Global Winds
 Patterns
of air circulation
 Named from direction from which they
blow
 Major global wind systems



Polar easterlies
Prevailing Westerlies
Trade winds
Global winds
Polar Easterlies
 Poles
to 60 latitude in both hemispheres
 Cold, dense air moves from poles to 60
 Can bring cold air to US making snow and
freezing weather
Prevailing Westerlies
 30
and 60 latitude in both hemispheres
 Flow from west to east
 Can bring moist air to US making rain and
snow
Trade Winds
 30
latitude almost to equator in both
hemispheres
 Due to Coriolis-curve to west in N.
Hemisphere and east in S. Hemisphere
 Traders used winds to move from Europe
to Americas.
Doldrums
•located where the
trade winds of the
two hemispheres
meet at the equator
• means “dull” or
“sluggish”
•an area of Low
pressure
The Horse Latitudes
 30
north and south latitude
 Very weak winds
Jet Stream: Atmospheric
Conveyor Belts
 Narrow
belts of high speed winds
 Blow in the upper troposphere and lower
stratosphere
 Can affect movement of storms and
airplane flights
Local Winds
 Move
short distances
 Blow from any direction
 Caused by temperature differences
 Sea breeze moves from sea to land
 Land breeze moves from land to sea
How does wind blow?
 Wind
will flow from high to low!!!
Wrapping it up
 What



role does the Sun play?
Sun heats the land and water, changing
temperatures
Different heating causes density
differences, causing wind!
UNEQUAL HEATING CAUSES THE WIND!
Temperature of Coast vs.
Inland
 Avg
temperature Atlanta: low-23 to 51:
28 degree difference for January
 Avg temp. for Savannah: low-38 to 60: 22
degree difference
 Avg for July: Atlanta-88

 Why


Savannah- 92
is Savannah warmer?
Gulf Stream runs by it and there is a
constant breeze blowing near the ocean
Lower temp range on coast
Sea Breeze
(Draw your own picture)
LOCAL WINDS
Sea Breeze vs Land Breeze
Label the diagram below, using the following terms:
Air moves to complete the cell
warm air rising
L (low pressure)
air currents move from water to land
cool air sinking
32°
23°
7.
6.
2.
4.
3.
Label the diagram below, using the following terms:
1.
C
Temperature of Coast vs.
Inland
 Coastal
areas don’t get as warm or as
cold as inland areas because it has the
ocean to moderate their temperatures.
Land Breeze
(draw your own picture here)
air moves to complete the cell
H (high pressure)
14°
warm air rising
cool air sinking
18°
air currents move from land to water
7.
2.
6.
4.
5.
C
3.
1.
C
Mountain Breeze vs,.
Valley Breeze