FC composition and structure of the atmosphere Flashcards
What is the earths atmosphere a mixture of
a mixture of transparent, odourless gases and aerosols held to earth by gravity
What are the three main type of constituents in the earths atmosphere
permanent gases
Variable gases
Aerosols
Define permanent gases and give examples
a gas that remains in the atmosphere at nearly constant concentrations over time. They do not easily change in response to environmental or biological processes
Eg nitrogen, oxygen, argon
Define variable gas
a gas whose concentration changes over time and space due to natural and human activity. They play significant role in climate and weather
Eg water vapour, carbon dioxide, methane
Define aerosol and give examples
aerosols are tiny solid or liquid particles suspended in the atmosphere
Eg sea salt, volcanic ash and sea salt
What is the difference between natural and anthropogenic gases
natural gases are those released into the atmosphere through natural processes. Anthropogenic gases are those released or significantly increased by human activity
What is the importance of carbon dioxide
major contribution to the greenhouse effect but essential for photosynthesis
What is the importance of methane
major contribution to the greenhouse effect and acid rain
What is the importance of nitrous oxide
major contribution to the greenhouse effect
What is the importance of ozone in both the stratosphere and the troposphere
stratosphere: filters UV radiation
Troposphere: health hazard
What is the importance of water vapour
clouds and precipitation
Major greenhouse gas
What is the importance os sulphur dioxide
volcanic origin contributes to acid rain
What is the importance of nitrous dioxide
produced by combustion, contributes to acid rain and smog
How do permanent gases arise
mostly passive in weather related processes
How do variable gases arise
occur as a result of both natural processes and human activities
What do variable gases affect
affect transmission of radiation through atmosphere
What are the 4 main layers of the earths atmosphere
- troposphere
- stratosphere
- mesosphere
- thermosphere
Between what distance will you find the troposphere
from the earths surface to roughly 10km
Describe the troposphere
3/4 of the atmospheres mass
Heated from below
Temperature generally decreases with height by 6.5 degrees per km from 17 - -52 degrees
Most weather occurs here
Between what distance will you find the stratosphere
between 10 to 50 km above the surface
Describe the stratosphere
stable (not a lot of vertical mixing) and dry
Temperature increasing to -3 degrees with height, heated by ozone absorbing UV light
Jet aircraft frequently enter this layer
between what distance do you find the mesosphere
Between 50 to 80 km above the surface
Describe the mesosphere
mass of atmosphere 0.1%
Density is too low for ozone chemistry to heat. Temperature falls to -93 with increasing altitude. Place of noctilucent clouds
What are noctilucent clouds
ice coated meteor dust
Between what distance do you find the thermosphere
between 80-700 km above the suface
describe the thermosphere
heated by UV ionisation and the solar wind
Place of aurora ( polar light)
Between what distance do you find the exosphere
Between 700-10,000 km above the surface
Describe the exosphere
density so low that space shuttles orbit here with little drag
Hydrogen and helium are the primary elements
Between what distance do you find the ionosphere
50-1,000 km above the surface
Encompasses the mesosphere, thermosphere and exosphere
Describe the ionosphere
ionised part of the atmosphere by solar radiation
Reflect many types of radio waves
Forms the inner edge of the magnetosphere
