Transcript The Earth`s Atmosphere

The Earth’s Atmosphere
Layers of Air
• There are 4 basic layers of air:
• 1. Troposphere
• 2. Stratosphere
• 3. Mesosphere
• 4. Thermosphere
100 Miles
Thermosphere
80 Miles
Mesosphere
60 Miles
Stratosphere
40 Miles
Ozone
20 Miles
Troposphere
-120
-100
-80
-60
-40
-20
0
20
40
60
Temperatures in degrees Celsius
80
100
120
Troposphere
• The _______________ is where all
weather takes place; it is the region of
rising and falling packets of air.
• The air pressure at the top of the
troposphere is only 10% of that at sea
level (0.1 atmospheres).
Troposphere
• The troposphere starts at the Earth's
_______________ and extends 8 to 14.5
kilometers high (5 to 9 miles).
• This part of the atmosphere is the most
dense.
• As you climb higher in this layer, the
temperature drops from about 17 to -52
degrees Celsius.
Stratosphere
• The _______________ starts just above the
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troposphere and extends to 50 kilometers (31
miles) high.
Above the troposphere is the stratosphere,
where air flow is mostly _______________.
The thin ozone layer in the upper stratosphere
has a high concentration of
_______________, a particularly reactive
form of oxygen.
Stratosphere
• The thin ozone layer in the upper
stratosphere has a high concentration of
ozone, a particularly reactive form of
_______________.
• This layer is primarily responsible for
absorbing the _______________from the
Sun.
• There is considerable recent concern that
manmade fluorocarbon compounds may
be depleting the ozone layer
Mesosphere
• The _______________ starts just above
the stratosphere and extends to 85
kilometers (53 miles) high .
• In this region, the temperatures again fall
as low as -93 degrees Celsius as you
increase in altitude.
Thermosphere (Ionosphere)
• The _______________ is very thin, but it
is where aurora take place, and is also
responsible for absorbing the most
energetic _______________ from the
Sun, and for reflecting radio waves,
thereby making long-distance radio
communication possible.
Thermosphere
• The thermosphere starts just above the
mesosphere and extends to 600
kilometers (372 miles) high.
• Temperatures in this region can go as
high as 1,727 degrees Celsius. Chemical
reactions occur much faster here than
on the surface of the Earth.
• This layer is known as the
______________________________.
Composition of the Atmosphere
• The atmosphere is primarily composed of
– _______________ - 78%
– _______________ - 21%
– _______________ - 1%.
Winds
• Jet Stream
• Once air begins moving, the Earth's
rotation causes it to follow a curved path;
this is referred to as the
_______________.
Jet Stream
• The term "jet stream" is often used to
refer to the ________________________
high in the atmosphere - above about
20,000 feet .
• These winds help determine the locations
of areas of high and low air pressure at
the Earth's surface.
• A jet stream is "a relatively narrow river of
very strong _______________ winds.
• Jet streams form along the upper air
boundaries of large masses of warm and
cold air.
• During major cold outbreaks over the USA,
the jet stream often dives south - staying
above the warm-cold boundary sometimes moving well over the Gulf of
Mexico.
• During unusually mild winter weather and
during the summer, the jet stream retreats
northward into Canada.
Jet Stream Patterns
Jet Stream Patterns
Jet Stream Patterns
Clouds
• Cirrus
• Stratus
• Cumulus
• Nimbus - prefix
Cirrus Clouds
• Cirrus clouds are thin, wispy clouds that
usually form above 18,000 feet.
• Cirrus clouds generally move from
_______________ to _______________
across the sky and usually "point" to fair
weather.
• Cirrus clouds are thin because they form
in the higher levels of the atmosphere
where little water vapor is present.
Cirrus Clouds
Stratus Clouds - Fog
• Fog forms when the air cools to a point at
which water vapor in it begins to
condense into tiny water droplets.
• The temperature at which water vapor will
begin condensing from the air at any
particular time is called the
"_______________."
• Stratus clouds are uniform gray clouds
that usually cover the entire sky.
• Stratus clouds look like a layer of fog that
never reaches the ground.
• Precipitation rarely falls from true stratus
clouds, but light mist and drizzle can
sometimes accompany stratus clouds.
Stratus Clouds
Cumulus Clouds
Cumulus Clouds
• Cumulus clouds form as water vapor
condenses in strong, upward air currents
above the earth's surface.
• These clouds usually have
_______________ and
_______________.
• Most cumulus clouds form below 6,000
feet and are relatively thin and associated
with fair weather.
• When the atmosphere becomes unstable,
and very strong, upward air currents form,
cumulus clouds can grow into cumulus
congestus, or _______________.
• If the atmosphere is unstable enough,
cumulonimbus clouds, better known as
thunderstorms, form.
• Cumulus congestus and cumulonimbus
clouds can tower from below 6,000 feet to
greater than 50,000 feet.
Cumulus Clouds
Other Cloud Types
Contrails
Mammatus Clouds
Mammatus Clouds
• These pouch-like clouds often form
underneath a thunderstorm where cooler
air sinks into warmer below the storm
cloud.
• _______________ clouds look
threatening, but actually signal the
weakening of a thunderstorm.
Precipitation
• Rain
• Snow
• Sleet
• Freezing Rain
• Hail
Rain
Snow
Sleet
Freezing Rain
Hail
Hail
Hail
Weather
• Thunderstorms
– Cumulus clouds, strong winds, heavy rain,
lightning, and thunder.
– Single Cell
– Multi Cell
– Supercell
Single Cell
Single Cell
• Severe weather is limited to brief, isolated
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– downbursts, small hail, heavy rain, and weak
tornadoes
– low degree of predictability of severe events
– low to moderate danger to public
– moderate to high danger to aviation.
Multicell
Multicell
Supercell
Supercell
Lightning
• _______________ - electrical discharge
that travels between 2 oppositely charged
surfaces (friction occurs between the
raindrops and ice crystals as they are
being pushed up and down in the clouds).
Lightning
• The upper portion of the clouds become
positively charged and the lower portion
becomes negatively charged.
• Eventually the charge in the lower portion
of the clouds becomes great enough to
pull away from the ground, making it
positively charged.
• Difference is great enough, the electrical is
discharged from the cloud to the ground.
Lightning
• Lightning follows the shortest path striking the tallest or highest object.
• We hear thunder because lightning heats the air
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to more than 43,000 degrees, causing the air to
quickly expand. The air then quickly cools after
the flash, which causes it contract.
This quick expansion and contraction of air
around the lightning starts air molecules moving
back and forth, making sound waves, which we
hear as _______________.
Tornado
• Intense storm with high winds that circle a
small center of extremely low pressure.
• Form along cold fronts.
• Spin _______________.
• _______________ - tornado over a body
of water like a lake.
Tornado
Tornado
Tornado
• Dr. Theodore Fujita
– Well known researcher.
– Came up with the Fujita scale - F1, F2, F3, F4,
F5
– Scale is based on the wind speed of a
tornado.
Hurricane
• Cyclonic storms that develops over warm
ocean water. (Get their energy from the
water)
• Western Pacific Ocean - ______________
• Indian Ocean - _______________
• Named after females until the late 70’s.
Hurricanes
The seven main characteristics that
define a hurricane, are:
• Hurricanes have no _______________.
• Hurricane winds weaken with height
• The centers of hurricanes are warmer than
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their surroundings
Hurricanes and tropical systems form under
weak high-altitude winds.
Air sinks at the center of a hurricane
Hurricanes' main energy source is the latent
heat of condensation
Hurricanes weaken rapidly over land
Tropical systems are classified into four
categories according to its degree of
organization and maximum sustained wind
speed.
• _______________, tropical wave:
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Unorganized mass of thunderstorms, very little, if
any, organized wind circulation.
_______________: Has evidence of closed
wind circulation around a center with sustained
winds from 20-34 knots (23-39 mph).
_______________: Maximum sustained winds are
from 35-64 knots (40-74 mph). The storm is
named once it reaches tropical storm strength.
_______________: Maximum sustained winds
exceed 64 knots (74 mph).