Weather Systems

Weather SystemsWeather Systems

SWBAT describe how the rotation ofEarth affects the movement of air;compare and contrast wind systems;identify the various types of fronts.SWBAT describe how the rotation ofEarth affects the movement of air;compare and contrast wind systems;identify the various types of fronts.

Global Wind SystemsGlobal Wind Systems

Coriolis effectCoriolis effect

–The rotation of earth causes particles such asair to be deflected to the right in the northernhemisphere and to the left in the southernhemisphere–The rotation of earth causes particles such asair to be deflected to the right in the northernhemisphere and to the left in the southernhemisphere

With a partnerWith a partner

In your own words describe how the rotationof Earth affects air movement.In your own words describe how the rotationof Earth affects air movement.

–The Coriolis effect causes air molecules to bedeflected to the right in the northern hemisphereand the left in the southern hemisphere. This,along with the imbalance of heating due to theangle sunlight strikes the earth, creates distinctglobal wind systems that transport warmer air tocolder areas and vice versa. The result is abalancing of heat energy on Earth.–The Coriolis effect causes air molecules to bedeflected to the right in the northern hemisphereand the left in the southern hemisphere. This,along with the imbalance of heating due to theangle sunlight strikes the earth, creates distinctglobal wind systems that transport warmer air tocolder areas and vice versa. The result is abalancing of heat energy on Earth.

Global Wind SystemsGlobal Wind Systems

Trade windsTrade winds

–Occur at 30° north and south latitude.–Occur at 30° north and south latitude.

–Air sinks, warms and moves toward the equator in awesterly direction.–Air sinks, warms and moves toward the equator in awesterly direction.

–When the air reaches the equator it rises again andmoves back toward 30° latitude, where the processstarts again.–When the air reaches the equator it rises again andmoves back toward 30° latitude, where the processstarts again.

–At 30° latitude there is a high pressure belt that causesweak face winds.–At 30° latitude there is a high pressure belt that causesweak face winds.

–At the equator there is a low pressure zone called theintertropical convergence zone–At the equator there is a low pressure zone called theintertropical convergence zone

Global Wind SystemsGlobal Wind Systems

Prevailing WesterliesPrevailing Westerlies

–These winds flow between 30°N and 60°N aswell as 30°S and 60°S.–These winds flow between 30°N and 60°N aswell as 30°S and 60°S.

–They flow in a pattern opposite to the tradewinds, with surface winds blowing toward thepoles in a generally easterly direction.–They flow in a pattern opposite to the tradewinds, with surface winds blowing toward thepoles in a generally easterly direction.

–These are responsible for the weather in theUS.–These are responsible for the weather in theUS.

Global Wind PatternsGlobal Wind Patterns

Polar EasterliesPolar Easterlies

–These winds lie between 60°N and S and therespective poles.–These winds lie between 60°N and S and therespective poles.

–They are similar to the trade winds, flowing fromnortheast to southwest in the northernhemisphere, and southeast to northwest in thesouthern hemisphere.–They are similar to the trade winds, flowing fromnortheast to southwest in the northernhemisphere, and southeast to northwest in thesouthern hemisphere.

–They are characterized by their cold air.–They are characterized by their cold air.

Global Wind PatternsGlobal Wind Patterns

Jet streamsJet streams

–Narrow bands of fast, high altitude, westerlywinds. They can flow up to 185 km/h.–Narrow bands of fast, high altitude, westerlywinds. They can flow up to 185 km/h.

How does the jet stream affect weather?How does the jet stream affect weather?

–Jet streams cause disturbances, creating largescale weather systems. It affects the intensityof weather by moving air of differenttemperatures from one region to another.–Jet streams cause disturbances, creating largescale weather systems. It affects the intensityof weather by moving air of differenttemperatures from one region to another.

In groups of 2-3In groups of 2-3

You will create a model of a globe that illustrates the globalwind patterns we have studied .You will create a model of a globe that illustrates the globalwind patterns we have studied .

You must mark the following latitudes on your globe:You must mark the following latitudes on your globe:

–Equator = 0°–Equator = 0°

–Horse latitudes = 30°N and 30°S–Horse latitudes = 30°N and 30°S

–60°N and 60°S–60°N and 60°S

–Poles = 90°N and 90°S–Poles = 90°N and 90°S

Also label the northern and southern hemispheresAlso label the northern and southern hemispheres

You must include:You must include:

–Trade winds pattern–Trade winds pattern

–Prevailing westerlies pattern–Prevailing westerlies pattern

–Polar easterlies pattern–Polar easterlies pattern

–Coriolis effect–Coriolis effect

–Intertropical Convergence Zone–Intertropical Convergence Zone

–Polar jet stream–Polar jet stream

–Subtropical jet stream–Subtropical jet stream

FrontsFronts

FrontFront

–The narrow region separating two air masses ofdifferent densities (caused by differences intemperature, pressure, and humidity)–The narrow region separating two air masses ofdifferent densities (caused by differences intemperature, pressure, and humidity)

Front TypesFront Types

Cold frontCold front

–Cold dense air displaces warm air and forces itupward in a steep front.–Cold dense air displaces warm air and forces itupward in a steep front.

–Clouds, showers, and thunderstorms areassociated with cold fronts.–Clouds, showers, and thunderstorms areassociated with cold fronts.

–It’s represented on a weather map by a solidblue line with blue trianglespointing in the direction ofthe front.–It’s represented on a weather map by a solidblue line with blue trianglespointing in the direction ofthe front.

Front TypesFront Types

Warm FrontWarm Front

–Advancing warm air displaces cold air. Due tothe slow movement of the cold air it develops agradual slope.–Advancing warm air displaces cold air. Due tothe slow movement of the cold air it develops agradual slope.

–It’s characterized by extensive cloudiness andprecipitation.–It’s characterized by extensive cloudiness andprecipitation.

–It’s represented on a weather chart by a solidred line with semicircles facing in thedirection of the front’s movement.–It’s represented on a weather chart by a solidred line with semicircles facing in thedirection of the front’s movement.

Front TypesFront Types

Stationary FrontStationary Front

–When 2 air masses meet and neither advancesinto the other’s territory the boundary stalls.–When 2 air masses meet and neither advancesinto the other’s territory the boundary stalls.

–They seldom have clouds or precipitation, butcan be similar to the weather of a warm front.–They seldom have clouds or precipitation, butcan be similar to the weather of a warm front.

–It’s represented on a weather chart by acombination of warm andcold fronts symbols.–It’s represented on a weather chart by acombination of warm andcold fronts symbols.

Front TypesFront Types

Occluded FrontOccluded Front

–Occurs when a cold air mass moves rapidly andovertakes a warm front. The cold air wedgesitself under the warm air, forcing it upward.When it forces the warm out of the way itcollides with another cold front.–Occurs when a cold air mass moves rapidly andovertakes a warm front. The cold air wedgesitself under the warm air, forcing it upward.When it forces the warm out of the way itcollides with another cold front.

–Precipitation is common on both sides of anoccluded front.–Precipitation is common on both sides of anoccluded front.

–It’s represented on a weathermap with an alternating line ofpurple triangles and semicircles–It’s represented on a weathermap with an alternating line ofpurple triangles and semicircles

Pressure SystemsPressure Systems

Describe and illustrate air movement in ahigh pressure system.Describe and illustrate air movement in ahigh pressure system.

–Air sinks and then spreads away from thecenter. It moves in a clockwise direction in thenorthern hemisphere and counterclockwise inthe southern, due to the Coriolis effect.–Air sinks and then spreads away from thecenter. It moves in a clockwise direction in thenorthern hemisphere and counterclockwise inthe southern, due to the Coriolis effect.

–Associated with fair weather.–Associated with fair weather.

Pressure SystemsPressure Systems

Describe and illustrate air movement in alow pressure system.Describe and illustrate air movement in alow pressure system.

–Air rises from the surface and is replaced by airfrom outside the system pulling it toward thecenter. It moves in a counterclockwise directionin the northern hemisphere and a clockwisedirection in the southernhemisphere.–Air rises from the surface and is replaced by airfrom outside the system pulling it toward thecenter. It moves in a counterclockwise directionin the northern hemisphere and a clockwisedirection in the southernhemisphere.

–Associated with cloudsand precipitation.–Associated with cloudsand precipitation.

With a partnerWith a partner

Answer questions 1-6, on page 311.Answer questions 1-6, on page 311.

Be sure to answer in complete sentences.Be sure to answer in complete sentences.

If you don’t finish in class you mustcomplete this for homework.If you don’t finish in class you mustcomplete this for homework.