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Dr. Hooda
Text Book page # 442 - 449
What is an air mass?
A large body of air having nearly
uniform conditions of humidity and
temperature at any given altitude.
1. According to humidity
• Wet air masses form over water
m- maritime
• Dry air masses form over land.
c- continental
2. According to Temperature
• Warm air forms over tropical regions near the equator.
T- Tropical
•
Cold air forms over polar regions. P- Polar
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• Moisture content is noted by the first
letter, which is lower case.
m – maritime – wet
c – continental – dry
• Temperature is noted by the second
letter, which is upper case.
P – polar – cold
T – tropical - warm
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• (cP) Continental Polar , “dry and cold ”
– closer to the Poles over land-locked regions.
• (cT) Continental Tropical , “dry and warm”
– closer to the Tropics over land-locked
regions.
• (mP) Maritime Polar , “wet and cold ”
– closer to the Poles over water.
• (mT) Maritime Tropical , “wet and warm”
– closer to the Tropics over water.
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Influence of an air mass over the
weather of an area
• As an air mass moves into an area, the
weather changes.
• Give an example.
The advancing edge of
a mass of cold or warm
air.
A front is a boundary
between air masses.
Four types of fronts and map symbols
The directions that the bumps face is the direction the front is
moving.
1. Cold front
2. Warm front
3. Stationary front
4. Occluded front
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When a fast moving cold air mass runs into a
slow moving warm air mass and the thicker cold
air slides under the lighter warmer air.
• Bring thunderstorms, rain or snow.
• Most tornadoes develop from
thunderstorms on the edge of a cold
front.
• Cold front followed by cooler drier air.
• http://www.mesoscale.iastate.edu/agron
206/animations/05_cnWfronts.html
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When a moving warm air mass collides with a
slowly moving cold air mass and the warm air
moves over the cold air.
• Brings drizzly precipitation.
• Followed by clear warm weather.
http://www.mesoscale.iastate.edu/agron206/animations/05_c
nWfronts.html
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When a cold air mass and warm air mass meet,
but neither air mass has enough force to move the
other air mass.
• Many days of cloudy, wet weather.
http://www.youtube.com/watch?v=VwI1NmESxss
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When a warm air mass is caught between two
cooler air masses and the thicker cold air masses
move underneath the thinner warm air mass and
push it upward.
• Brings cool temperatures with large amounts of
rain or snow
http://www.youtube.com/watch?v=4gc7puH279s
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Cold Front, Warm Front and
Occluded Front Animation
• http://www.phschool.com/atschool/phsciexp/active_art
/weather_fronts/
• http://www.classzone.com/books/earth_science/terc/c
ontent/visualizations/es2002/es2002page01.cfm?chap
ter_no=visualization
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• When air masses collides, fronts_ are
formed.
• Sometimes fronts becomes distorted.
• Distortion can be caused by surface
features, such as mountains, or
strong winds (jet stream).
• Bends can develop along the front.
• Air begins to swirl.
• Gives rise to Cyclones and
Anticyclones.
• Area with lower pressure than
surrounding area.
• Winds spiral toward the
center.
• Rising air causes stormy
weather.
• Hurricanes that form over the
Indian Ocean are called
cyclones.
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• Rotation of air
around high
pressure center.
• Dry, clear weather
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Quiz
1.
Describe a maritime polar (mP) air mass, in terms of
moisture and temperature.
2. What is the name of an air mass that forms over water?
3. What is the name of an air mass that forms over land?
4. What is the name of an air mass that forms in a cold
region?
5. What is the name of an air mass that forms in a warm
region?
6. Describe a continental tropical (cT) air mass, Moisture and
temperature.
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Quiz
7. The boundary between two air masses is called a
______________________.
8. A cold air mass meets and pushes a warm air mass out of
the way. What type of front am I?
9. A warm air mass is trapped between to cold air masses.
What type of front am I?
10. A warm air mass meets and pushes a cold air mass out of
the way. What type of front am I?
11. I am a front that brings drizzly rain and am followed by
warm clear weather. Name me.
12. A cold air mass meets a warm air but neither is very
strong. They are separated and many days of wet ,
cloudy weather occur.
13. Which types of fronts can you
find on this map?