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Water
vapor is the most important gas in
the atmosphere.
Water changes state with the addition or
subtraction of heat energy.
Melting
Evaporation
Condensation
Sublimation
The
heat released during a change of
state.
Latent heat released during condensation
is an important energy source for severe
weather in the atmosphere (i.e.
thunderstorms, hurricanes, etc.)
The
general term used to describe the
amount of water vapor in the air.
Mixing Ratio = expresses the quantity of
water vapor contained in a specific amount of
air.
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The
ratio of the air’s actual water vapor
content to its potential water vapor
capacity at a given temperature.
The
Water
Temperature
vapor condenses to form clouds.
form when air is cooled below its
dew point temperature.
Clouds
temperature to which the air would
need to be cooled to reach saturation.
changes that occur without
the addition or subtraction of heat are
called adiabatic temperature changes.
The dry adiabatic rate is 10 ⁰ C per 1000
meters.
If
When air is
compressed, the
temperature raises
adiabatically.
When air expands, the
temperature drops
adiabatically.
a parcel of air rises high enough, it will
eventually cool to its dew point
temperature and water vapor will begin to
condense to form a cloud composed of
droplets.
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Above
the dew point, latent heat of
condensation stored in the water vapor will
be liberated, decreasing the rate of
adiabatic cooling.
The wet adiabatic rate of cooling is
between 5 and 9 ⁰ C per 1000 meters
Under
average atmospheric conditions, air
resists vertical movement.
There are 4 mechanisms that cause air to
rise:
• Orographic lifting
• Frontal wedging
• Convergence
• Localized convective lifting
Elevated
terrain acts as a barrier to air
flow.
It explains why the windward side of a
mountain is wet and the leeward side is
dry.
The result can be an arid landscape called
a rainshadow desert.
The Great Basin Desert is an example.
Cooler,
denser air acts as a barrier over
which warmer (more humid) less dense air
rises.
Air
in the lower atmosphere flows ****.
occurs when air moves from a
smooth surface such as the ocean, over
rough terrain where friction reduces its
speed.
It is also a major contributor to middlelatitude cyclones.
Often
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Localized Convective Lifting
Unequal
temperature of Earth’s surface
may cause parcels of air to be warmed
more than the surrounding air.
These warmer (more humid, less dense)
parcels of air will be lifted upward.
When
they rise above the condensation
level, clouds form and may produce midafternoon thunderstorms.
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Resists
vertical movement.
Produces
clear or partly cloudy skies.
If
there is precipitation, it will be light and
short.
Formed
when warm humid air is forced
aloft.
The energy needed to create unstable air
is provided by latent heat released during
condensation.
May produce towering clouds and rain.
May generate thunderstorms or even a
hurricane.
Cirrocumulus
http://www.diracdelta.co.uk/science/source/c/l/clouds/cirrocumulus-001.jpg
http://interactive.usc.edu/members/jchen/cloudchart.gif
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Cirrus
Cumulonimbus
http://www.freewebs.com/thomp730/Cirrus%20clouds-Horz.jpg
http://upload.wikimedia.org/wikipedia/commons/8/82/Wagga-Cumulonimbus.jpg
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Altocumulus
Altostratus
http://quest.arc.nasa.gov/aero/virtual/demo/w
eather/tutorial/images/altostratus.jpg
http://cl0uds.files.wordpress.com/2009/02/altocumulus.jpg
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Stratocumulus
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Stratus
http://ocw.usu.edu/Forest__Range__and_Wildlife_Sciences/Wildland_Fire_Management_and_Planning/indicator1.jpg
http://quest.arc.nasa.gov/aero/virtual/demo/weather/tutorial/images/altostratus.jpg
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Cumulus
2. http://www.sinap.ac.cn/water08/pic/350px-Water_molecule_svg.png
5. http://sci.gallaudet.edu/Mary/latent-heat.jpg
6. http://i.usatoday.net/weather/_photos/2007/10/10/humidity-topper.jpg
7. Flasks:
http://www.geography.hunter.cuny.edu/~tbw/wc.notes/4.moisture.atm.stability/relative_humidity.htm
7. Circles:
http://geography.cst.cmich.edu/Franc1M/4Geo105/images/lectures/moisture/relativehumidity.gif
8. Grass: http://apollo.lsc.vsc.edu/classes/idm3020/tut_folder/nick_tutorial/Images/grass-dew.jpg
8. Table: http://wwc.weatherbug.com/images/bugtoday/dew_point.jpg
9. http://www.weatherquestions.com/Cloud_formation_convective.gif
11. Pump: http://i.ehow.com/images/GlobalPhoto/Articles/4797253/122840-main_Full.jpg
11. Tire: http://i.ehow.com/images/GlobalPhoto/Articles/4561378/valvestemcover-main_Full.jpg
17. http://web.mst.edu/~rogersda/umrcourses/ge301/press&siever12.3.png
18. http://www.geography.hunter.cuny.edu/~tbw/wc.notes/4.moisture.atm.stability/frontal.wedging.jpg
27. http://www.efluids.com/efluids/gallery/gallery_images/lenticular_cloud.jpg
http://www.caenz.com/info/downloads/photolibrary/PhotoLib/MiscOther/images/Cumulus%20clouds.jpg
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