Earth Processes Part 3:
Atmosphere (weather)
Weather #1
The parts that make up
the universe:
Atmosphere- consists of the
“air”…gases.
Hydrosphere- consists of the “water”
Lithosphere- consists of the “land”
Biosphere Includes all three!!! All
organisms are found w/in the
biosphere.
Lithosphere
Hydrosphere
Atmosphere
What is Air?
It’s Got Us Covered
•Air is made up of
nitrogen, oxygen,
carbon dioxide, &
water vapor.
• Air is made up
of matter- it
takes up
space.
• Air is a mixture
of gases- tiny
fast moving
particles in
motion.
Composition
of the
Atmosphere
Weather
• Weather- The condition of the
atmosphere at a certain place and
time.
• When talking about weather, you
are actually describing what is
happening in the atmosphere.
• Weather is constantly changing.
• Without the atmosphere, there
would be no weather!
Feeling the Air
• Dark colored materials heat up quicker
than light colored materials. So air
above dark colored surfaces heats up
quicker.
• When air is warmed the particles spread
out.
• Warm air becomes lighter & rises. The
cooler air sinks.
• This movement of air is called WIND.
Wind is represented
by this symbol.
It is called a wind
barb.
The barbs point in the
direction from which
the wind is blowing
FROM.
The more
“tails”
there are
on the
barb…
the
stronger
the wind.
The circle
attached to the
wind barb tells
you the “cloud
cover”.
The top left
number
represents the
temperature in
degrees
Fahrenheit.
The number in
the bottom left
corner
represents the
dew point.
•Dew points
represent the
amount of
moisture in the
air.
The thing
dividing the
temperature and
the dew point is
called the
“weather
symbol”.
In this
case…there is
fog.
The number in the
right corner
represents sea level
pressure.
We will not get into
this.
Land & Sea Breezes
Land Breeze
(cool land/warm sea)
Sea Breeze
(warm land/cool sea)
• Cool air over land • Warm air over the
moves out toward
land rises.
the water and
• Cool air over the
takes the place of
water moves
rising air.
toward land and
• Warm air over the
takes the place of
water rises.
the warmer air
that has risen.
Weather terms you need to know…
•Humidity - measure of the amount of
water vapor (moisture) in the air.
•Dew point - When air is cooled to the
temperature at which it can hold no more
water vapor, it comes together and “dew”
(water droplets) form.
•Precipitation - moisture coming down
from the atmosphere. Rain, snow, hail,
sleet (frozen rain).
•Evaporation - water changing into
gas…going into atmosphere.
•Condensation - gas changing into
water. (dew)
•all three of these terms are involved in water
cycle
Barometric pressure- measure of the
pressure caused by Earth’s gravitational
force pulling on the column of air above
you.
High pressure (H) - fair weather,
sunshine
Low pressure (L) - gray, cloudy skies
and sometimes precipitation
Clouds
How do they form??
•Water vapor in the air reaches its dew
point and condenses into water droplets.
• Clouds are classified/named by their
HEIGHT & SHAPE
•Height will come 1st and shape 2nd!!!
•Clouds can give us clues of upcoming
weather.
Types of Clouds
3 main shapes:
Cirrus
Stratus
Cumulus
Based on height & shape…
Height will come 1st and shape 2nd!!!
Cirrostratus
Cirrocumulus
Altostratus
Altocumulus
Nimbostratus
Stratocumulus
Cumulonimbus
•SHAPE:
•Flat clouds = Stratus (St)
•Fluffy clouds = Cumulus
(Cu)
•Wispy clouds = Cirrus (Ci)
•HEIGHT:
•CirroHighest clouds
•AltoMiddle level clouds
•StratoLowest clouds (usually just name
of cloud with out a prefix)
Nimbus, nimbo =
Dark and rainy
Cumulonimbus = thunderstorm cloud
that takes up all levels…type of cloud to
form tornadoes.
What are fronts?
A front is where TWO air masses meet.
Changes in weather take place along a front.
•Cold Front
Leading edge of colder air that is replacing
warmer air.
•Warm Front
Leading edge of warmer air that is replacing
cooler air.
•Occluded Front
When a cold front catches up to a
warm front.
Moving together.
•Stationary Front
A front that is NOT moving!
http://ww2010.atmos.uiuc.edu/%28Gh%29// guides mtr/af/frnts/cfrnt/prcp.rxml
http://ww2010.atmos.uiuc.edu/%28Gh%29/guides/mtr/af/frnts/wfrnt/prcp.rxml
Reading weather maps…
Weather maps have many things going
on.
You need to know and be familiar with
all the symbols.
A thunderstorm is a storm with
lightning AND thunder, produced by
a cumulonimbus cloud, usually
producing gusty winds, heavy rain
and sometimes hail.
Thunderstorm Development
•Thunderstorms develop in warm, moist
air ahead of eastward-moving cold
fronts.
•Require strong updrafts and
downdrafts. (vertical winds)
•Weather systems (storms) move west
to east!
Fun Facts about Thunderstorms:
•The typical thunderstorm is 15 miles in diameter and
lasts an average of 30 minutes. Nearly 1,800
thunderstorms are happening at any moment around the
world.
• Every thunderstorm produces lightning, (but you
can’t always see it or it doesn’t touch down). It kills
more people each year than tornadoes. You can estimate
how many miles away a storm is by counting the
number of seconds between the flash of lightning and
the clap of thunder. Divide the number of seconds by
five to get the distance in miles.
•MYTH: If it is not raining, then there is no danger from
lightning.
FACT: Lightning often strikes outside of heavy rain and may
occur as far as 10 miles away from any rainfall.
•MYTH: The rubber soles of shoes or rubber tires on a car will
protect you from being struck by lightning.
FACT: Rubber-soled shoes and rubber tires provide NO protection
from lightning. However, the steel frame of a hard-topped vehicle
provides increased protection if you are not touching metal.
Although you may be injured if lightning strikes your car, you are
much safer inside a vehicle than outside.
•MYTH: "Heat lightning" occurs after very hot summer days and
poses no threat.
FACT: What is referred to as "heat lightning" is actually lightning
from a thunderstorm too far away for thunder to be heard.
However, the storm may be moving in your direction!
Lightning!!!!! The
attraction of opposite
charges (static electricity).
• When lightning strikes (touches the
ground)….actually half came down from
the bottom of cloud (stepped leader) and
half came up from the ground (streamers).
• Two opposite electrical charges are
attracted and meet halfway…once they are
connected….charges flow!!!
•What is Thunder???
•The sound that results from a flash of
lightning and is caused by sudden
expansion of the air in the path of the
electrical discharge.
•Lightning always produces thunder. They
actually happen at the SAME time.
•Light and sound move at different
speeds. Light travels faster than sound.
DOPPLER
RADAR - helps
detects
thunderstorms
Thunderstorm lingo:
•single cell - normal, one storm
•multicell clusters - many single cell
storms
•squall lines- a line of storms together
(multicell)
•supercell - severe thunderstorms with
strong winds that spin and spiral….can
develop into a tornado!!!! Also can
produce large hail.
Tornadoes!!!!!
•Tornadoes are produced inside powerful
thunderstorms, which in turn are created near the
junction between warm/moist air and cold/dry
air.
•The greatest activity occurs in April, May, and
June (Spring/Summer), but no month is free of
them.
•The most favorable areas for tornado activity
include Texas, Kansas, Oklahoma, and Missouri.
•“Tornado Alley” - most tornadoes occur (Texas
up to S. Dakota)
•Tornadoes that touch down on water are called
waterSPOUTS.
•Strong tornadoes can form from a “wall
cloud”
•Watch - before the weather develops…the
conditions are right.
•Warning - the weather condition is occurring
or has occurred close to your area…take
precautions.
Remember
that storms
have
UNSTABLE
air produced
by different
temperatures
and updrafts
& downdrafts
(lifts).
BEHAVIOR
BEHAVIOROF
OFTHE
THEAIR/GASES
AIR/GASES
Boyle’s
Boyle’sLaw
Law
•Robert
•RobertBoyle
Boyleinvestigated
investigatedthe
the
relationship
relationshipbetween
betweenthe
thevolume
volumeofofaagas
gas
and
andits
itspressure.
pressure.
•What
•Whatdoes
doespressure
pressuredo
dototothe
thespace
spaceaagas
gas
takes
takesup?
up?
•More
•Morepressure
pressure--smaller
smallergas
gasspace
space
•Less
•Lesspressure
pressure--bigger
biggergas
gasspace
space
Less pressure =
more volume
(larger gas space)
More pressure =
less volume
(smaller gas space)
Charles’s Law
•Jacques Charles investigated the
relationship between the volume of a gas and
temperature.
•He noted that the volume of a gas increased
with the temperature.
•Temperature increase = increase volume,
gas particles move faster (expand/rise)
•Temperature decrease = decrease volume,
gas particles slow down (sinks)