Atmospheric Composition Flashcards
Where is Earth’s atmosphere densest?
Sea level
What is the atmosphere for?
provides a filter/shield during the daytime and acts as a blanket as night
Where are most molecules in the atmosphere found and why?
Earth’s surface because of gravity
What is the atmospheric composition?
Nitrogen - 78%
Oxygen - 21%
Argon - 0.93%
Carbon dioxide - 0.04%
Water vapor - 0-4%
What are the non-variable gases?
N, O2, Ar, CO2
What is the main variable gas?
water vapor
How are atmospheric layers defined? and what is that?
via lapse rates, which is the change of temp with height
What is the order of the atmospheric layers? bottom to top
Troposphere (tropopause), stratosphere (stratopause), mesosphere (mesopause), thermosphere, exosphere
Troposphere
- lowest layer
- most molecules here
- temp decreases 3.5F with height
- most weather happens here
- top boundary is higher where it’s warm, lower where it’s cool
- sea level to approx 11 miles
- ranges from 60F to -60F
Stratosphere
- temperture increases with height due to ozone
- atmospheric ozone is here
- 11miles to 30mi
- ranges from -60F to 5F
Thermosphere
- technically part of Earth’s atmosphere but air density is so low, parts of it is considered outer space
- spacecraft orbit here
- Northern Lights occur here
- 50mi to 375mi
- temp increases due to high insolation absorption
-62mi is where space begins
Exosphere
-uppermost portion
- gradually fades into the vacuum of space
- air is very thin
What causes the Northern Lights
Charged particles (protons, electrons, and other ions) from space collide with atoms and molecules in thermosphere, exciting them into higher energy states. The molecules and atoms shed that extra energy by emitting light photons
