This document contains definitions and descriptions of various atmospheric and meteorological phenomena. It defines dry adiabatic and wet adiabatic rates as how air temperature changes with compression and expansion. It also describes how winds interact with mountainous terrain, creating warmer and drier conditions on the leeward side. Various cloud types like cirrus, cumulus and stratus clouds are defined based on their appearance and composition. Precipitation types such as rain, snow, sleet and hail are also explained in terms of the temperature and environmental conditions required for their formation.

1. By: Nicole Irvine

2.  Definition: when air
compresses it gets warmer,
when it expands, it cools
 Air at high pressures, that
compresses and heats to 10
degrees Celsius, moves
downward; which is called
dry adiabatic rate
 Air that cools after
condensation begins and is
released, heat then works
against the adiabatic
cooling; which is called wet
adiabatic rate
http://www.bio.georgia
southern.edu/bio-
home/harvey/lect/lectu
res.html?ccode=el&mda
=scrn&flnm=abel&ttl=P
opulations%20and%20th
eir%20environment

3.  Definition: elevated
terrains act like
barriers to air flow
(Ex: Mountains)
 On a mountain, the
windward side would
be cold and moist;
leeward side is dry
and warm
 When air descends, it
warms adiabatically
https://earthscience-in-the-
nationalparks.wikispaces.com/Death+
Valley

4.  Definition: large masses
of warm and cold air
meeting, causes a front
 When the two masses of
air meet, colder air is
denser and is like a
barrier against the
warmer air
 Fronts that are weather
producing have to do
with specific storm
systems; called middle-
latitude cyclones
geo.hunter.cuny.edu

5.  Definition: when air in
lower atmosphere
flows together it then
lifts
 May lead to adiabatic
cooling and/or
possible cloud
formations
 Depending on patterns
of air movement,
thunderstorms may
form or occur
http://zebu.uoregon.edu/ph121/conv
erge.html

6.  Unequal heating of
Earth’s surface, on hot
days, can cause pockets
of air to be warmed more
than the surrounding air
 Localized convective
lifting is a process that
produces rising thermals
 When parcels that are
warm rise above the
condensation level,
clouds form
santasusana.org

7.  If temperatures drop
because of expansion its
because the volume of the
air was forced to rise
 Stable air: remains in it’s
position; Unstable air:
tends to rise
 Clouds that have air that’s
unstable are more likely
to cause
thunderstorms/tornadoes
academic2.american.edu

8.  Air must be saturated for
condensation to occur
 For water vapor to
condense, it must have a
surface
 When condensation
happens, air above the
ground have condensation
nuclei appear
 When condensation takes
place the growth rate of
cloud droplets increase
decorating.visitacasas.com

9.  Cirrus: high, white,
thin, wispy fibers
 Cumulus: flat
base, appearance
of rising towers
 Stratus: sheets or
layers that cover
the sky
windows2universe.org

10.  3 types: Cirrus,
Cirrostratus,
Cirrocumulus
 All of these are thin,
white, and made of
ice crystals
 They aren’t
considered
precipitation makers
eo.ucar.edu

11.  Appear at 2,000-
6,000 meters high
 Larger and denser
than other clouds
 Light snow or drizzle
may come from
these clouds
braindanceisawayoflife.blogspot.com

12.  3 types: Stratus,
Stratocumulus,
Nimbostratus
 May produce light
precipitation
 “Nimbus”- means rainy in
Latin
 “Stratus”- means cover w/
layer in Latin
chr.wikipedia.org

13.  Some clouds don’t fit
into specific
categories
 Some have low
height, and expand
upward
 When upward
movement happens
and the acceleration
is powerful, clouds
then have great
vertical range to form
kidsresearchexpress-3.blogspot.com

14.  Has the same
appearance and
structure of a cloud
 Defined as a cloud with
its base close to the
ground
 Fog can produce in
mornings or nights
when Earth’s surface
cools by radiation
brainharmonycenter.com

15.  When water is cooled
below 0 degrees Celsius
its called “super cooled”
 Ice crystals grow as cloud
droplets do, when they’re
big enough they will fall
 When the surface
temperature is above 4
degrees Celsius,
snowflakes will melt
before reaching the
ground
physorg.com

16.  Rainfall is related to clouds
located below the freezing
level
 Rain drops formed in warm
clouds have a process
called “collision-
coalescence” process
 When large droplets move
through clouds they collide
and coalesce
web.me.com

17.  In meteorology, rain
means drops of water
that fall from a cloud
 At low temperatures,
light snow made of
individual six-sided ice
crystals may form
 Temperatures warmer
than -5 degrees Celsius,
cause crystals to join in
large clumps
madmikesamerica.com

18.  Small particles of clear ice
is called sleet
 Sleet can form by a layer
of air (with temperatures
above freezing) overlie
subfreezing near the
ground
 Hail produces in
cumulous clouds by ice
pellets growing by
collecting super cooled
water droplets
pix.10tv.com