Please take out your Skills WS and check your work with a desk partner. Be ready to ask any questions on 15.2.

15.3 Global Winds and Local Winds

Copy into your IAN!

Objectives:1. Explain the

relationship between air pressure and wind direction.

2. Describe global wind patterns.

3. Explain the causes of local wind patterns.

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/

video/player/science/earth-sci/weather-101-sci.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 EffectApparent 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

Savannah- 92 Why 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 cool air sinking L (low pressure) air currents move from water to land 23° 32°

Label the diagram below, using the following terms:

7.

1. C

2.

3.

4.

6.

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 warm air rising cool air sinking H (high pressure) 14° 18° air currents move from land to water

7.

4.

2.

1. C 3.

6.

5. C

Mountain Breeze vs,. Valley Breeze