Atmosphere Flashcards
Atmosphere is a mixture of…
solids, liquids and gases that is held to the earth by gravitational force.
The outer limit of atmosphere is…
1000km.
Weather occurs…
up to 16-17 km from the ground.
About 99% of the atmosphere is…
concentrated in the lowest 40 km.
Above 40km the atmosphere is…
virtually a vaccum.
Composition of atmosphere:
Nitrogen (78%)
Oxygen (21%)
Argon (0.9%)
Trace gases such as CO2, helium and ozone are present.
In atmosphere there is also…
water vapour and solids such as dust and ash.
Ozone layer is concentrated…
at 25-30km. This is important for filtering out suns UV radiation.
In atmosphere there is a steep…
pressure gradient as air pressure decreases with height.
Air pressure exists because…
of the weight given to air by gravity, so at higher altitudes where air is thinner , it is also lighter.
Thinner air absorbs…
less solar energy so increase in height decreases temperature.
Thermosphere
Temperature increases rapidly with height (reach up to 1500 degrees). Increasing amount of atomic oxygen absorbs incoming radiation.
Thermosphere apart form this is…
virtually a vaccum.
Mesosphere
Temperatures fall rapidly(no water vapour, cloud, dust or ozone to absorb incoming radiation). Very strong winds up to 3000km/h
Stratosphere
- Temperature rises with height(temperature inversion) due to increase in ozone.
- Pressure continues to fall
- The air is dry, wind speed increases.
