Transcript air masses and fronts

AIR MASSES AND
FRONTS
Chapter 16 Section 2
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Air Mass
A large body of air where
temperature and moisture
content are similar throughout
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• Warm air forms over tropical regions near the
equator.
T- Tropical
•
Cold air forms over polar regions.
P- Polar
• Wet air masses form over water
m- maritime
• Dry air masses from over land.
c- continental
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• Moisture content - first letter.
m – maritime – wet
c – continental – dry
• Temperature - second letter.
P – polar – cool
T – tropical - warm
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Description of air masses:
– Continental polar (cP)- cool and dry
• Continental arctic-type of continental polar mass that is
much colder-forms in the arctic circle
– Continental tropical (cT)- warm (hot)
and dry
– Maritime polar (mP)- humid (wet) and
cold; unstable
– Maritime tropical (mT)- humid (wet)
and warm; unstable
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• mP- maritime polar air mass
• cP – continental polar air mass
• mT – maritime tropical air mass
• cT – continental polar air mass
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An air mass is a large body of air that has similar
temperature and moisture properties
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•
A boundary between air masses.
•
Four types of fronts and map symbols
1.
2.
3.
4.
Cold front
Warm front
Occluded front
Stationary front
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WARM FRONT
• Warm air mass meets a cold air mass
and pushes the cold air mass out of the
way.
• Brings drizzly precipitation followed by
clear warm weather.
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Symbol:
Clouds, Storms,
and rain accompany
warm fronts.
• Warm Front Animation:
– http://ww2010.atmos.uiuc.edu/(Gl)/guides/crclm/act/gifs/fpr
4.gif
– http://earthsci.org/processes/weather/weaimages/2e.gif
COLD FRONT
• Cold air mass meets a warm air mass and
pushes the warm air mass out of its way.
• Bring thunderstorms, rain or snow.
• Most tornadoes develop from
thunderstorms on the edge of a cold front.
• Followed by cooler, drier air.
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Symbol:
Cold Fronts can
cause heavy
snow or ice if
there is enough
water vapor in
the air.
STATIONARY FRONT
• Cold air meets warm air.
• Not enough force to move either front.
• Many days of cloudy, wet weather.
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Symbol:
• Where they meet, water
vapor in the warm air
condenses into rain,
snow, fog or clouds
• Can stall out for days
Stationary Fronts:
•
Stationary Front Animation:
–
http://www.usatoday.com/weather/tg/wsfront/wsfront.htm
OCCLUDED FRONT
• Warm air caught between two cold air
masses.
• Brings cool temperatures with large
amounts of rain or snow
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Occcluded Fronts:
The two cooler air masses
meet in the middle and
may mix.
The warm air mass is cut
off (or occluded) from the
ground.
•
http://www.uwsp.edu/geo/f
aculty/ritter/images/atmos
phere/weather/cold_occlus
ion.gif
Symbol:
Cold Front, Warm Front and
Occluded Front Animation
• http://www.3villagecsd.k12.ny.us/Murphy/me
dina/weather.html
• http://www.classzone.com/books/earth_scien
ce/terc/content/visualizations/es2002/es2002
page01.cfm?chapter_no=visualization
• Click on the above links.
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