Study, 006-Earth Atmosphere

■ Summary

- Troposphere (대류권)

- Stratosphere (성층권)

- Mesosphere (중간권)

- Thermosphere (열권)

- Exosphere (외권)

■ Troposphere:

- Air heated by sun-warmed ground

- Warm closest to ground/sea level

- Heat from bottom causes convection

- 기상현상, 공기 75% 수증기 99% 분포, 극 지역 0-7km, 적도 지역 0-20km, 중위도 지역 0-17km

- 공기구성: 78.1% 질소, 21.0% 산소, 0.9% 기타 기체

- Planetary boundary layer: 지면과의 마찰력으로 공기흐름이 영향을 받음. 0.2-2km

- Tropause: 대류권/성층권 경계면. 온도가 고도에 따라 감소하지 않고 일정

- 온도가 높이에 따라 선형적으로 감소: -60ºC at 12 km

- Oxygen comes from biological processes

- Life on Earth for 3.8 billion years (Earth is 4.5 billion years old)

- Humidity, pressure, temperature decease with altitude

■ Tropopause

- Boundary between the troposphere and the stratosphere

- The jet stream is just below the tropopause: 400 km/h speed

■ Stratosphere

- Ozone layer (at 00 km) blocks the sun's UV light

- If the sun's UV light is not blocked, you will get a bad burn in 10 seconds.

- Ozone generated naturally in stratosphere by sunlight

- Temperature increases with altitude: no convection, stable air (no mixing, no turbulence)

- Maximum height: 45-50 km

- Air is very dry (little water vapor): no cloud except in polar regions in winter at 15-25 km and at -78ºC

- Air is very thin.

■ Stratopause

- Boundary between the stratosphere and the mesosphere

■ Mesosphere

- Altitude: 50-85 km

- Meteors

■ Thermosphere

- Altitude: 85-690 km

- Fades off into thin interplanetary gas

- UV radiation ionizes the gas in the thermosphere creating the ionosphere

- AM and short-wave radio waves bounce off of ionosphere

- Auroa

- Space Shuttle

■ Exosphere

- Altitude: 690-10,000 km

■ Gas pressure of atmosphere

- Each gas molecule attracted to a planet by gravity

- Gas molecules hit each other

- Balance of forces determines atmospheric pressure

- Highest at the surface and decreases smoothly as altitude increases

- On Earth, atmospheric pressure decreases by a factor of 2 every 5.5km

■ Vapor pressure (= equilibrium vapor pressure):

- Pressure exhibited by vapor present above a liquid surface

- Pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in a closed system.

- An indication of a liquid's evaporation rate.

- High vapor pressure = volatile.

- Vapor pressure vs temperature: nonlinear, Clausius-Clapeyron relation

- Boiling point: at a given atmospheric pressure, vapor pressure = ambient atmospheric pressure

- Partial pressure: h=0m, T=20ºC, saturated with water vapor, water vapor 2.3kPa, nitrogen 78kPa, oxygen 21kPa, 0.9kPa argon → a total of 102.2kPa standard atmospheric pressure

- Antoine equation: vapor pressure vs temperature

- Boiling point of water:

1 Torr = 1/760 atm = 133.3 Pa

- Saturation vapor pressure = equilibrium vapor pressure

- Equilibrium vapor pressure of water

- RH (relative humidity) = (partial pressure of water vapor) / (equilibrium vapor pressure of water)

■ Physical data by altitude

- Air density

- Temperature vs altitude

[Ref]

International standard atmosphere: cavcar