Unit 6: Atmospheric Systems & Society Flashcards
What are the 3 main gases in our atmosphere?
- nitrogen
- oxygen
- argon, ozone, CO2, water vapor, etc.
What percent of our atmosphere is made up of nitrogen?
78%
What percent of our atmosphere is made up of oxygen?
21%
What percent of our atmosphere is made up of argon, ozone, CO2, water vapor, etc.?
1%
How do we divide our atmosphere into 4 layers? (what factor determines how we divide our atmosphere)
temperature
What are the four layers of the atmosphere? (from lowest level of elevation to highest)
troposphere, stratosphere, mesosphere, thermosphere
troposphere
the layer closest to the Earth’s surface
How much of the atmosphere’s mass does the troposphere contain?
75%
In which layer of the atmosphere do most of the clouds/weather exist?
troposphere
How are temperature and pressure affected as you travel up the troposphere?
temperature and pressure drop
How far does the troposphere extend from the Earth’s surface?
about 10-15 km
In the stratosphere, why does temperature increase with altitude?
- the ozone layer absorbs the greater part of the solar ultraviolet radiation
- the air in the stratosphere is much less dense (thinner) than in the troposphere, so it doesn’t take as much energy to warm this air as it would to warm denser air closer to the ground
How far does the stratosphere extend from the Earth’s surface?
about 15-50 km
How far does the mesosphere extend from the Earth’s surface?
about 50-80 km
In the mesosphere, how is temperature affected with an increase in altitude?
temperature decreases
What unique process occurs in the mesosphere?
meteors burn up
How far does the thermosphere extend from the Earth’s surface?
about 80-320 km
Despite having hot temperatures, why would the thermosphere feel very cold to us?
this layer of the atmosphere is very thin, meaning there are not enough gas molecules to transfer heat to you
What two natural processes does our atmosphere do?
- greenhouse effect
- ozone shield/ozone layer
What does the greenhouse effect do?
keeps the planet warm by trapping long wave radiation from the planet
What does the ozone shield do?
blocks unwanted UV radiation, protecting life on Earth from cataracts, skin cancer, etc.
Why do temperature and pressure decrease with increasing altitude in the troposphere?
the gases in the troposphere do not absorb/emit solar radiation, instead the Earth’s surface absorbs this radiation; therefore, as a result of conduction and convention, the tropospheric heat is most concentrated at lower altitudes
Why does temperature decrease with increasing altitude in the mesosphere?
There are fewer gas molecules to absorb the Sun’s radiation (no ozone layer)
Why does the thermosphere get so hot?
the few molecules that are present in the thermosphere receive extraordinary amounts of of energy from the Sun, causing the layer to warm to high temperatures