This document contains summaries of various atmospheric and weather concepts written by Jessica Keller for her Period 4 class. It discusses adiabatic temperature changes, orographic lifting, frontal wedging, convergence, localized convective lifting, stability, condensation, cloud types, precipitation processes, and fog. Citations are provided for the images used.

1. By: Jessica Keller
Period 4

2. Adiabatic Temperature Changes
and Expansion and Cooling
 These are the temperature changes that happen even though heat is not
added or subtracted, the result is when the air is compressed.
 When the air is allowed to expand, it cools, and when the air is compressed,
it warms.
 The latent heat works against the adiabatic cooling process, even though
the air will continue to cool.

3. Orographic Lifting
 When there are elevated terrains, like mountains, they act like a barrier
to the air flow.
 When the air goes up a slope on a mountain, the adiabatic cooling
makes clouds and precipitation.
 An example of this would be, the Great Basin, it lies a few hundred
kilometers from the Pacific Ocean, and it is cut off from the ocean’s
moisture by the Sierra Nevada Mountains.

4. Frontal Wedging
 Occurs when the masses of warm air, and the masses
of cold air collide a form a front.
 The cooler and denser air acts like a barrier over the
warm, less dense air, which rises.
 These weather producing fronts coordinate with
storms called middle latitude cyclones.

5. Convergence
 When air masses collide , it makes the air rise and
whenever air is in the lower atmosphere, the result is
lifting.
 When air flows in from more than one direction, the
air rises.
 And example of this would be the Florida Peninsula,
on warm days the flow of air is from the ocean to the
land, causing a pileup of air along the coasts and
causes convergence over the peninsula.

6. Localized Convective Lifting
 The uneven heating of the Earth’s surface may cause pockets of air to
be heated more than the air around them.
 The process of convective lifting produces thermals, which is the rising
air.
 Also, when the warm air rises above the condensation level, this is
clouds form using convective lifting.

7. Stability (Density Differences &
Stability & Daily Weather)
 When air rises, its temperature drops because it is expanding, but if it was
cooler than the air surrounding it then it would sink. This is called stable air,
which resists vertical movement.
 Stability Movements- The stability of the air is determined by measuring
the temperature at different heights.
 Degrees of Stability- Air is considered stable when the temperature
decreases with increasing altitude.
 Stability and Daily Weather- Has to do with the creation of clouds using
orographic lifting, frontal wedging, and convergence.

8. Condensation
 Condensation is when the water vapor in the air
changes to a liquid.
 It can occur in a form of fog, dew or clouds.
 For these condensation to occur, however, the air must
be saturated, which is when the air is cooled to its dew
point.

9. Types of Clouds
 There are three types of clouds, these include:
 Cirrus Clouds- These are high, white, and thin clouds. They occur as
patches or fibers and have a feather like appearance.
 Cumulus Clouds- These clouds are clouds that consist of round, big cloud
masses. They normally have a flat base and tend to be very big.
 Stratus Clouds- These clouds look like sheets because they are in layers and
cover most of the sky.

10. High Clouds
 The high clouds are made up of three different types of
clouds: Cirrus, Cirrostratus, and Cirrocumulus.
 The high clouds are often thin and white and made up
of ice crystals, which form because of the very low
temperatures.
 These clouds are not usually precipitation makers.

11. Middle Clouds
 The middle clouds appear in the sky in the middle
range, usually between 2000 to 6000 meters.
 Made up of Altocumulus clouds, which are composed
of rounded cloud masses. These clouds are also larger
and denser then most.
 These clouds may experience infrequent light snow, or
drizzle.

12. Low Clouds
 The low clouds are made up of three different types of
clouds: Stratus, Stratocumulus, and Nimbostratus.
 These clouds cover most of the sky, and may produce
some precipitation.
 However Nimbostratus clouds are one of the main
precipitation makers, and form during stable
conditions.

13. Clouds of Vertical Development
 Some of the clouds have their bases in the low height range but they
often extend up into the middle or even high altitudes, however they all
relate to stable air.
 Whenever there is a upward movement, the acceleration is powerful
and what forms is clouds with great vertical range.
 The end result is a Cumulonimbus cloud that produces rain and
thunderstorms.

14. Fog (By Cooling and By
Evaporation)
 Fog is defined as a cloud with its base at or near the ground.
 Fog cause by cooling is formed on cool, clear nights when the Earth’s
surface is cooled by radiation. When the air comes in contact with the
ground it is cooled below its dew point, which creates fog.
 Fog cause by evaporation when cool air moves over warm water and the
moisture is evaporated to produce saturation. When the rising water
meets the cold air, it condenses and causes fog.

15. Cold Cloud Precipitation (Bergeron
Process)
 Cold cloud precipitation relies on two physical
processes: super cooling and super saturation.
 When water is in the liquid state below zero degrees
Celsius it is super cooled.
 When the air is saturated, it is considered super
saturated.

16. Warm Cloud Precipitation
(Collision-Coalescence Process)
 In a warm cloud, the Collision- Coalescence Process is
what forms raindrops.
 When water absorbing particles, like salt, remove
water vapor from the air, at relative humidities less
than 100%, this forms large raindrops.
 As these large raindrops move throughout the cloud
they collide and join together with smaller droplets.

17. Rain and Snow
 The definition of rain is drops of water that fall from a
cloud and have a diameter of 0.5 mm.
 Also, when the surface temperature is 4 degrees
Celsius, the snowflakes usually melt and fall as rain.
 At very low temperatures, snow occurs, which is light,
fluffy, and made up of six sided ice crystals.

18. Sleet, Glaze and Hail
 Sleet is small particles that are clear, and form a layer
of air with temperatures above freezing.
 Glaze is like a freezing rain, and happens when
raindrops get super cooled as they go through
subfreezing air.
 Hail is made in Cumulonimbus clouds, and begin as
only small ice particles, but grow by collecting super
cooled water droplets.

19. Works Cited (Pictures)
 http://www.kidsgeo.com/geography-for-kids/0070-adiabatic-temperature-changes.php
Adiabatic Temperature Changes and Expansion and Cooling
 http://ocw.usu.edu/Forest__Range__and_Wildlife_Sciences/Wildland_Fire_Managemen
t_and_Planning/Unit_7__Atmospheric_Stability_and_Instability_3.html
Orographic Lifting
 http://www.geo.hunter.cuny.edu/~tbw/wc.notes/4.moisture.atm.stability/frontal_wedgi
ng.htm
Frontal Wedging
 http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/cld/dvlp/cnvrg.rxml
Convergence
 https://www.meted.ucar.edu/sign_in.php?go_back_to=http%253A%252F%252Fwww.met
ed.ucar.edu%252Fnorlat%252Fsnow%252Flake_effect%252Fprint_whole.htm
Localized Convective Lifting

20. Works Cited Cont. (Pictures)
 http://www.fas.org/irp/imint/docs/rst/Sect14/Sect14_1b.html
Stability
 http://keep3.sjfc.edu/students/kes00898/e-
port/condensation%20page%20for%20unit.html
Condensation
 http://www.enchantedlearning.com/subjects/astronomy/planets/earth/clouds/
Types Of Clouds
 http://cimss.ssec.wisc.edu/satmet/modules/clouds/highclouds.html
High Clouds
 http://www.climate4you.com/ClimateAndClouds.htm
Middle Clouds
 http://www.atmos.illinois.edu/earths_atmosphere/clouds.html
Low Clouds

21. Works Cited Cont. (Pictures)
 http://www.free-online-private-pilot-ground-school.com/Aviation-Weather-
Principles.html
Clouds of Vertical Development
 http://www.google.com/imgres?q=fog&hl=en&safe=active&biw=1365&bih=559&gbv=2&t
bm=isch&tbnid=VvVXTe2iWya2PM:&imgrefurl=http://www.brainharmonycenter.com/b
rain-
fog.html&docid=uZKGt4B2tjgIaM&imgurl=http://www.brainharmonycenter.com/images
/brain-fog.jpg&w=800&h=600&ei=-
6z0TsmVKqje0QHK5b2wAg&zoom=1&iact=rc&dur=218&sig=115237740818284051629&pa
ge=1&tbnh=119&tbnw=160&start=0&ndsp=23&ved=1t:429,r:4,s:0&tx=53&ty=62
Fog
 http://dnr.wi.gov/org/caer/ce/eek/earth/groundwater/precip.htm
Cold Cloud Precipitation
 http://all-free-download.com/free-vector/vector-clip-art/rain_cloud_clip_art_17461.html
Warm Cloud Precipitation

22. Works Cited Cont. (Pictures)
 http://www.windows2universe.org/earth/Atmosphere/precipitation.html
Rain and Snow
 http://www.edupic.net/weather_gr.htm
Sleet, Glaze, and Hail