Atmospheric Movement and Local Weather

*Let’s Review

*Air Masses

*Air Pressure

0 o Equator 30 o S 60 o S 90 o S30 o N60 o N90 o N

MoreDirect Sun Hot

*Convection Currents

*Global Convection Cells

*Global Wind Patterns

*The Coriolis Effect

*Jet Stream

*Jet Stream

*Forms high in the upper Troposphere between two air masses of different temperatures

*Higher temperature difference = faster speed

*Due to the Coriolis Effect, it flows around air masses.

*Polar Jet:

*It dips southward when frigid polar air masses move south.

*It tends to stay north in the summer months

*Jet Stream Animation

http://www.pbs.org/wgbh/nova/vanished/jetstr_five.html

Abnormally high surface ocean temperatures off the coast of South America

Causes unusual weather patterns across the globe

*El Nino

*A strong surface current

*Begins at the tip of Florida

*Flows up the eastern coastline of the

U.S.

*Crosses the Atlantic Ocean

*Causes warmer climate in NW Europe

*Gulf Stream

*Reflection Question

*Why does the Earth have wind and ocean currents?

*Variables Affecting Local Weather

*Fronts

*When convection and winds cause air masses to move, they bump into one another.

*The area where two air masses meet is called a front.

*Most severe weather occurs near frontal boundaries.

*Cold Front- Cold air meets warm air- Fast moving and stormy, severe weather is likely

*Cold Front Symbol

*Warm Front- Warm air meets cold air- Slow moving with less severe weather

*Warm Front Symbol

*Stationary Front

*Warm and cool air masses that are not strong enough to move one another

*Sits still for a long period of time

*Stationary Front Symbol

*Friction

*Frontal Boundary Simulations

http://www.stevemcentee.com/animation3.html

*High and Low Pressure Circulation

*Air Pressure and Wind

*Air pressure is measured with a barometer in millibars.

*Millibars are represented by connected lines of equal pressure. This is a lot like the topographic map lines.

*The closer together the lines are, the faster the wind speed.

*The farther apart the lines are, the slower the wind speed.

*The Earth’s Insulator

*The Sun heats the water and land every day.

*Land heats up rapidly, but cools off rapidly.

*Desert

*Water heats up slowly, but cools off slowly.

*Swimming at night

*The heat retained by the oceans is what keeps our planet insulated.

*Land and Sea Breezes

*The heating and cooling of water and land produces land breezes and sea breezes.

*High pressure moves toward low pressure, pushing the warm air upward.

*As warm air rises, cooler air moves in and replaces it.

*Land Breeze

*Sea Breeze

*Sea Breeze and Land Breeze

Simulation

http://www.classzone.com/books/earth_science/terc/content/visualizations/es1903/es1903page01.cfm?chapter_no=visualization

*Reflection Question

*How do global patterns of atmospheric movement affect local weather?