Download Air pressure and Weather

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Weather and Climate Power
Point
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Atmospheric Composition
Our “air” is made up of:
78% Nitrogen
21% Oxygen
0-4% Water Vapor
0.93% Argon
.038% Carbon
Dioxide
0.01% Trace Gases
(Carbon dioxide has increased
from 0.028% over the past 150
years)
Layers of the Atmosphere:
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Exosphere- the traditional boundary
between Earth’s atmosphere and outer
space.
Thermosphere: The layer has extremely
low density which causes the
temperature, temp is more than 1000°C.
Last/Outer Layer
of our
Atmosphere
This layer also contains the Aurora from solar wind!
Mesosphere: This layer actually
decreases in temperature.
This is the layer that protects us from meteoroids!
Stratosphere- Here temperature
increases with altitude, especially in the
Ozone Layer. The UV absorption of UV
radiation in the ozone causes the
temperature to rise.
The OZONE layer protects humans from the
extremely dangerous UV waves from the Sun.
Surface of Earth
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Air Pressure
• Air Pressure is the weight of the air pressing
down on you.
• Air Pressure and Elevation- As you go higher
in elevation, the air molecules are more
spread out, therefore the air is less dense.
Also, there is less air above you being pulled
down on you by gravity.
• Air pressure and Weather:
Sunny Weather= High Pressure (approx the
weight of a school bus!)
Cloudy/Rainy Weather = Low Pressure (approx
the weight of a Volkswagen beetle)
Why don’t humans crush if we are always
under such extreme pressure?
Air Pressure is measured
with a barometer.
Heat TransfersThe way heat is exchanged on Earth.
Radiation: The direct transfer of
heat through the air.
Ex: sunlight, heat given off from
a fire or stove
Conduction: The transfer of
heat from one object to another.
Ex: heat from the hot pot to your
hand
Convection: The circulation of
heat through a liquid or gas.
Ex: Convection currents in the
mantle or a boiling pot of water.
Why does warm air rise?
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Cirrus tell that there will be
a storm in a couple of days
Fair
sunny
weather
These are the
only vertical
clouds and
are the huge
thunderstorm
and tornado
clouds.
Rain but not
thunderstorms
Cloud Formation- clouds form by tiny water droplets attaching to dust
particles in the sky. Eventually the drops will build up on the dust until it
becomes heavy enough for gravity to pull it to the Earth’s surface as
precipitation.
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The Water Cycle
Global Wind Systems:
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Polar Easterlies
Prevailing Westerlies
Northern Trade
Winds
ITCZ Low Pressure
Intertropical
Convergence Zone
Southern Trade Winds
Prevailing Westerlies
Polar Easterlies
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Types of Precipitation
A. Rain- liquid precipitation
B. Sleet- frozen ice pellets (less
than 5cm)
C. Freezing Rain- comes down as
a liquid but freezes on contact
leaving a glaze of ice.
D. Snow- frozen, six-sided
crystals.
E. Hail- (only forms in
cumulonimbus clouds) ice
pellets that circulates vertically
in the clouds and forms layers
as it grows bigger.
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Air Mass- large volume of air
that has characteristics of the
area over which it forms.
A (Arctic)- Extremely cold and
dry, forms over northern
Canada.
cP (Continental Polar) dry
and cold, forms over central
Canada.
mP (Maritime Polar) Cold and
wet, forms over northern
Pacific and Atlantic oceans.
mT (Maritime Tropical) warm
and wet, forms over southern
Pacific and Atlantic Oceans.
cT (Continental Tropical)
Warm and dry, forms over
Mexico in the SUMMER
ONLY.
•Types of Air Masses
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Examples of Areas that
have specific Air
Masses
cP- Central Canada, North
Dakota, Siberia
mP- Maine, Northern
Canadian Coast, Washington
and Alaska
mT- Florida, Rainforests,
Northern Australian Coast
cT- Texas, Mexico, Los
Vegas, Arizona
A- Northern Siberia, Arctic
Circle, Northern Canada and
Alaska and Greenland
cP
mP
mT
mT
cT
A
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Fronts- The boundary at the front of an air mass
The front created depends on the characteristics of the air
mass..
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Cumulonimbus Clouds- these are the dangerous thunderstorm clouds,
they are also called thunderheads. These clouds usually form on a hot
and humid day when the warm air rises quickly
Lightning- is a sudden spark or discharge released from energy within a
cumulonimbus cloud. Lightning can be up to 30,000°C.
Thunder- is the sound of the explosion. Since light travels so much
faster than sound, you always see the lightning first, than HEAR there
explosion within seconds of the lightning.
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Tornadoes- is a rapidly whirling, funnel-shaped cloud that
reaches from the cloud to the Earth’s surface.
Tornadoes usually last less than 15 minutes but within that
time, tornadoes can have winds speeds up to 320 miles per
hour and be up to half a mile wide!
TV Warning vs WatchThunderstorm or tornado Warning means that there IS A
STORM or funnel cloud and it is heading your way!
Watch means that there is a very good chance that the
thunderstorm and tornado COULD FORM.
Tornado Safety- safest places are a strong cement basement
or bath tub with a mattress over your body. If in a car, get out!
Get to a bridge overpass or lie in a ditch with your hands over
your head away from any objects that could become
projectile.
Cause for Tornado Alley:
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1. cP Air Mass from the north mixes with the mT from the south. The large
temperature contrasts cause the formation of supercells (extremely powerful
thunderstorms). The rotation begins within the thunderstorm clouds and the
updrafts create a column which increases rotation. The air pressure lowers in
the center causes a violent increase in wind speed.
The Fujita Scale Rates
Tornadoes :
F0-F1 (last 1-10 minutes
and winds up to 45-120
mph)
F2-F3 (last 20 minutes,
winds up to120-220mph)
F4- F5 (Last up to 1 hour,
winds are up to 220340mph)
What is the most violent
season for tornadoes?
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Location of Tornado Alley
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Hurricanes:
Hurricane Irene
Hurricane Formation:
1.
2.
3.
4.
5.
6.
7.
8.
9.
Warm air absorbs moisture from the
ocean.
Water Vapor is lifted into the
atmosphere.
As the water vapor rises, the cooler
upper air condenses it into liquid
droplets.
Condensation releases latent heat into
the atmosphere, making the air less
dense.
As the lighter air rises, moist air from the
ocean takes its places creating a wind
current.
Moving air begin the rotate due the
Coriolis Effect (the process curving
large wind and water systems due to the
very fast rotation of the Earth)
Tropical Depression- Some
thunderstorms and winds are 25-40 mph
Tropical Storm- thunderstorm wall
becomes more solid, winds 42-78mph
Hurricane or Cyclone- distinguished
eye with a surrounding eyewall (layers of
thunderstorms that surrounds the eye)
and winds are more than 78 mph.
Hurricane Katrina
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Climate- the average year after year
conditions of temperature, precipitation,
wind, and clouds of an area.
Tropical Moist Climates (Af) rainforest-Rainfall is heavy, more than 250
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*cm. (100 in.),temperatures of 27°C (80°F),Humidity is between 77 and
88%.
Wet-Dry Tropical Climates (Aw) savanna-there is a very wet season and
a very dry season. It gets a little cooler during this dry season but will
become very hot just before the wet season.
Dry Tropical Climate (BW) desert biome-These desert climates are
found in low-latitude deserts approximately between 18° to 28°This
makes for a very dry heat. The dry arid desert is a true desert climate,
and covers 12 % of the Earth's land surface.
Moist Continental Climate (Cf) Deciduous Forest biome- This climate is
in the polar front zone - the battleground of polar and tropical air
masses. Seasonal changes between summer and winter are very large.
Daily temperatures also change often. Abundant precipitation falls
throughout the year.
Dry Midlatitude Climates (Bs) grasslands biome- Annual temperatures
range widely. Summers are warm to hot, but winters are cold. These dry
climates are limited to the interiors of North America and Eurasia.
Boreal forest Climate ( Dfc) taiga biome-This is a continental climate
with long, very cold winters, and short, cool summers. Very cold air
masses from the arctic often move in.
Tundra Climate (E) tundra biome- Polar and arctic air , The winter
season is long and severe, A short, mild season exists, but not a true
summer season, technically a desert due to very little precipitation
Highland Climate (H) Alpine Biome- Highland climates are cool to cold,
found in mountains and high plateaus. Climates change rapidly on
mountains, becoming colder the higher the altitude gets. The climate of
a highland area is closely related to the climate of the surrounding
biome.
Marine Biome- All fresh and saltwater ecosystems.