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
What 2 abiotic factors cause changes in our atmosphere?
- temperature
- precipitation
Why is it important to use many forms of proxy data?
the accuracy of any particular one cannot be counted on 100% of the time
What 2 biotic factors cause changes in our atmosphere?
- plants
- animals
proxy data
preserved physical characteristics of the environment that can stand in for direct measurements
How can we measure the concentration of ancient atmospheric gas?
ice cores (bubbles trapped in ice)
What are 3 examples of proxy data?
- tree rings
- pollen fossils
- sediments
Without the greenhouse effect, how much cooler would the Earth be?
33°C cooler (91.4°F)
What does our average temperature allow for in terms of water?
our average temperature allows water to be liquid
What percent of incoming solar radiation is absorbed, scattered, or reflected by the atmosphere and clouds before it reaches the Earth’s surface?
almost 50%
What percent of incoming solar radiation reaches the Earth’s surface?
55%
What happens to the 55% of incoming solar radiation that reaches the Earth’s surface?
4% is reflected and 51% is absorbed in processes like photosynthesis, heating the ground and seas, and evaporation
What is incoming solar radiation mostly made up of?
visible light, UV light, and infrared light
How many bonds must greenhouse gas molecules have?
2 or more bonds
What are 4 greenhouse gases?
- water vapor (H2O)
- carbon dioxide (CO2)
- methane (CH4)
- ozone (O3)
ozone
a molecule made up of 3 oxygen atoms
How does ozone protect life on Earth?
ozone blocks incoming ultraviolet radiation
At what altitude are the highest ozone concentrations?
20-40 km
How is the ozone layer an example of a dynamic equilibrium?
ozone is continuously made from oxygen atoms and is continuously converted back to oxygen
How many parts per million is the ozone layer?
1-10 ppm
In what 2 layers of the atmosphere is ozone found?
the stratosphere (good) and the troposphere (bad)
How can UV radiation be absorbed in both the formation and destruction of ozone?
O2 is split under the influence of UV radiation resulting in two individual oxygen atoms, which can combine with another O2 to form ozone (O3); ozone can also absorb radiation and split into an oxygen molecule (O2) and and oxygen atom (O)
UV-C radiation
highest energy (shortest wave-length) and is therefore the most harmful type of radiation
How much UV-C radiation does the ozone layer absorb?
more than 90%
How much UV-B radiation does the ozone layer absorb?
about 50%
UV-A radiation
relatively harmless, low energy (longer wavelength)
What is the wavelength of UV-A radiation?
315-400 nm
What is the wavelength of UV-B radiation?
280-315 nm
What is the wavelength of UV-C radiation?
100-280 nm
What are 4 beneficial effects of radiation?
- stimulates the production of vitamin D
- can be used to treat skin diseases like vitiligo or psoriasis
- can be use to sterilize
- industrial uses like lasers, forensic analysis, or lighting
What are 7 damaging effects of radiation?
- genetic mutations
- damage to living tissues
- cataract formation in eyes
- skin cancer
- suppresses immune system
- damages phytoplankton
- damages zooplankton
How long have scientists been measuring the amount of ozone in the stratosphere above Antarctica?
since the 1950s
What did scientists observe in regards to the ozone in the stratosphere above Antarctica?
the amount of ozone decreased significantly during the spring and increased again in November
During the last 30 years, how has the ozone layer above Antarctica changed?
the minimum thickness of the ozone layer has reduced drastically and recovery is taking longer