Transcript The Atmosphere - Bremen High School District 228

The Atmosphere
The Atmosphere
• Earth’s atmosphere serves a vital role in our
survival, it
– Blocks harmful uv rays
– Maintains our warm temperature
– Supplies the oxygen we need to breathe
• As we learned in out last unit, our activities
have comprised the atmosphere’s role in
protecting us
The Atmosphere
• Earth’s atmosphere is comprised of 78%
Nitrogen, 21% Oxygen, and 1% of other gases
that surround the planet.
• Water vapor makes up part of the “other” 1%,
but can fluctuate between 0 and 4%. The
higher the water vapor, the more Nitrogen
and Oxygen decrease.
Atmospheric Concentrations
The Atmosphere
• The further we go out from Earth’s surface, the
thinner the atmosphere is, until it reaches space
• The atmosphere is broken into four main layers
(we’ve reviewed the first 2 already) followed by
the exosphere – which is basically outer space
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Troposphere
Stratosphere
Mesosphere
Thermosphere ( contains the ionosphere)
The Atmosphere
• Troposphere
– First layer above Earth’s surface (reaches from 720km above the ground)
– Half of Earth’s atmosphere exists in the
troposphere
– Weather occurs in the troposphere
– We also previously learned that pollution in this
layer causes smog and bad ozone production
The Atmosphere
• Troposphere (cont)
– This layer is heated from the ground (as the sun
warms the Earth, the ground radiates, or heats)
the troposphere. So, the further upward we go
into the troposphere, the colder it gets.
– The air also gets thinner the higher up you go (this
is what it get’s harder for some people to breathe
in higher elevations, such as mountains
– Most the water vapor and dust particles in the
exist in this layer, so most clouds occur here.
Kinds of Clouds
• 3 basic kinds…
1. Cirrus – light and feathery. Made of ice
crystals at 10,000m
2. Cumulus – big and puffy. Made from rising
currents of warm air that build to great
heights
3. Stratus – sheet like. Form layer upon layer at
low altitudes.
Fog
• A cloud that forms near the ground is fog.
• Fog forms from condensation.
• You see this when cool air moves in over warm
air usually in…
– Valleys
– Rivers
– Lakes
– Other low areas
Cumulonimbus Clouds
• Cumulus clouds that are associated with
thunderstorms.
• Updrafts can raise high to the top of the
troposphere.
– The top flattened and looks like an anvil.
– An anvil is a good indication a thunderstorm is
coming.
Let’s Name that Cloud….
Let’s Name that Cloud….
Let’s Name that Cloud….
Let’s Name that Cloud….
Let’s Name that Cloud….
The Atmosphere
• Stratosphere
– 2nd layer from Earth’s surface (between 16-50 km
above the Earth)
– Very stable, allowing for jet aircraft to fly here to avoid
the turbulence they experience in the troposphere
– The ozone layer exists here, absorbing radiation from
the sun. This process heats the stratosphere.
– The further up you go into the stratosphere, the
hotter it gets (opposite of the troposphere)
– Very little water vapor here, so almost no clouds
(polar stratospheric clouds are the exception - PSCs)
PCSs
• Found at altitudes of 15 to 25 km (9.3 to 15.5
miles
• They appear to help create “Ozone Holes” by
encouraging certain chemical reactions that
destroy ozone.
PCSs
The Atmosphere
• Mesosphere
– Third layer up from the Earth. Goes from 50-85km
high
– The higher you go up in the Mesosphere, the colder it
gets (like the troposphere)
– We don’t know much about this layer, because
satellites orbit above it, and weather balloons and jet
aircraft can’t fly high enough to reach it
– We know that most meteors from space burn up in
this layer (so we don’t get hit by them often)
– One kind of cloud forms here – Noctilucent Clouds
Noctilucent Clouds
• A special type of clouds, called "noctilucent
clouds“ (PMCs), sometimes forms in the
mesosphere near the North and South Poles.
• They form much higher than any other type of
cloud
• There are also odd types of lightning in the
mesosphere. These types of lightning, called
"sprites" and "ELVES"
PMCs
The Atmosphere
• Thermosphere
– 4th layer from the Earth (goes from 90km – between
500-1000km high)
– Temperatures sharply increase the higher you go in
the thermosphere and is influenced by solar activity
(from 200-2000 degrees C or 360-3632 degrees F)
– Even though it’s considered part of Earth’s
atmosphere, the air density is so low that it’s
considered mostly the same as outerspace.
– Aurora (the Southern and Northern Lights) occur here
Atmospheric Temperatures
The Atmosphere
• Thermosphere
– The lower portion of the thermosphere is called
the Ionosphere
– The ionosphere is a layer of electronically charged
particles
– When solar energy collides with these particles, it
creates ions and free electrons, which interfere
with radio waves sent from Earth, bouncing them
back. This is how AM radio transmissions can
bounce from one side of the Earth to the other.
Radio waves and the Ionosphere
The Atmosphere
• Exosphere
– Above the Thermosphere, where outer space
starts. For most part, not considered Earth’s
atmosphere
– The is the layer where air molecules escape into
space
– Space shuttles orbit the Earth here
– There are so few to no air molecules, so there is
no wind. So the wings of the shuttles(which are
used in the lower layers) are useless here