1. The Atmosphere

2. 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

3. 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.

4. Atmospheric Concentrations

5. 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
Troposphere
Stratosphere
Mesosphere
Thermosphere ( contains the ionosphere)

6. The Atmosphere Troposphere
First layer above Earth’s surface (reaches from 7-20km 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

7. 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.

8. Kinds of Clouds 3 basic kinds…
Cirrus – light and feathery. Made of ice crystals at 10,000m
Cumulus – big and puffy. Made from rising currents of warm air that build to great heights
Stratus – sheet like. Form layer upon layer at low altitudes.

9. 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

10. 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.

11. Let’s Name that Cloud….

12. Let’s Name that Cloud….

13. Let’s Name that Cloud….

14. Let’s Name that Cloud….

15. Let’s Name that Cloud….

16. The Atmosphere Stratosphere
2nd layer from Earth’s surface (between 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)

17. 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.

18. PCSs

19. 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

20. 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"

21. PMCs

22. The Atmosphere Thermosphere
4th layer from the Earth (goes from 90km – between km high)
Temperatures sharply increase the higher you go in the thermosphere and is influenced by solar activity (from degrees C or 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

23. Atmospheric Temperatures

24. 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.

25. Radio waves and the Ionosphere

26. 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