Atmospheric Science Exam Notes

Atmosphere Basics

  • Most abundant gas: Nitrogen.
  • Weather occurs mainly in the troposphere.

Warming Mechanisms

  • Earth emits primarily infrared radiation.
  • Greenhouse effect: caused by water vapor and carbon dioxide.
  • Blackbody: absorbs and emits all radiation perfectly.

Air Temperature

  • Greatest daily temperature range: clear and calm conditions.
  • Thermometer measures temperature.
  • Land heats/cools faster than water.

Humidity

  • Relative humidity depends on temperature and vapor pressure.
  • Dew point: air becomes saturated.
  • High dew point: moist air.

Clouds and Fog

  • Cumulonimbus clouds: thunderstorms.
  • Radiation fog: cooling of moist air over cold surfaces.
  • Cirrostratus clouds: halos around sun/moon.

Stability

  • Unstable air parcel: continues to rise when lifted.
  • Dry adiabatic lapse rate: 10°C/km10°C/km
  • Conditional instability: depends on moisture.

Cloud Development & Precipitation

  • Bergeron process: ice crystal growth at the expense of water droplets.
  • Sleet: snowflakes melt and refreeze.

Pressure and Winds

  • Barometer measures atmospheric pressure.
  • Winds blow from high to low pressure.
  • Geostrophic winds: balance between pressure gradient and Coriolis force.

Local Winds

  • Sea breeze: during the day.
  • Katabatic winds: cold downslope winds.

Global Circulation

  • Subtropical jet stream: around 30°30° latitude.
  • Trade winds: between equator and 30°30° latitude.
  • ITCZ: rising air, storms.

Air Masses and Fronts

  • cP air mass: cold and dry.
  • Warm front: steady precipitation, warm air lifted.
  • Cold fronts move faster than warm fronts.

Severe Weather

  • Thunderstorm formation: requires moisture, lift, and instability.