7: Atmosphere Flashcards
What is the atmosphere? What is it composed of?
- Layer of air surrounding earth, gravity keeps it from floating away
- 78% nitrogen, 21% oxygen, <1$ CO2, O3, water vapour, particles (pollen, pollution, dust)
What is atmospheric pressure? Avg?
The force exerted due to particles colliding, avg 101.3kPa at sea level
What is a kPa?
100kg of force over 1m^2
Where is air thinnest?
Higher altitude, bc there are less particles, less collisions
Why does warm air rise?
Temp increase = volume of particles increase = density decrease
What is wind?
Air particles moving from high pressure to low pressure ares (less concentration of particles)
Name the layers of the earth, how high they are, and their characteristics.
Troposphere: 0-15km, meteorological phenomena
Stratosphere: 15-50km, ozone, temp increase
Mesosphere: 50-80km, cold, few particles
Thermosphere: 80-500km, HOT, absorbs sun rays, aurora borealis/shooting stars here
Exosphere: 500km+, temp?, satellites, no air
What is general atmospheric circulation?
Warm air from equator rises to poles and cold air from poles flows towards equator (convection mvmt)
What is the coriolis effect?
Air masses deviating perpendicularly from their initial trajectory due to the earth’s axis rotation. AKA prevailing winds (winds circulating in loops)
Which direction does the coriolis effect go? In which layer of the Earth?
Right in the Northern hemi, left in the Southern; troposphere
What meteorological phenomena are influenced by the coriolis effect?
Cold/warm fronts, cloud formation
Name the 3 prevailing winds, their direction, and location in latitude
Polar cell (60N/S to pole): easterlies Ferrel cell (30-60N/S): westerlies Hadley cell (equator-30N/S): easterlies
What affects wind to blow in a certain direction?
Pressure
What are jet streams?
Powerful winds blowing between cells at high altitude (west>east)
How many jet streams are there? Names?
2 per hemi: subtropical, polar
What are air masses? What do they influence?
Large expanses of atmosphere with same temp/humidity; weather