Chapter 11
Characteristics of the Atmosphere
- Gases: Nitrogen 78%, Oxygen 21% and Argon .93%
- Compounds: Carbon dioxide and Water vapor (0.0 to 4.0%) (water cycle)- regulate amount of energy absorbed in atmosphere
- Layered into zones
- Ozone- importance to humans (protection from UV radiation)
- Atmospheric Dust- small particles-example H2O
A. Troposphere- all weather takes place
Carbon dioxide and Water Vapor
Thickest layer over the equator and a thinner layer over poles
Temperature decreases as altitude increases
Tropopause- temp. remains constant
B. Stratosphere- ozone concentrated
Ozone- “heavy oxygen”: O3
C. Mesosphere- coldest layer of the atmosphere. Air thin and chemical reactions are taking place (-130° F)
D. Thermosphere- Nitrogen/Oxygen absorb solar energy. Sometimes called
Ionsphere- ions and free electrons.
Exosphere- indefinite altitude
I. Solar Energy- know figure 11-5
a. Radiation-transfer of energy through space by electromagnetic waves (remember the electromagnetic spectrum).
- Higher temperatures emit shorter wavelengths. More energy!
- 50% of incoming solar radiation is absorbed directly or indirectly.
- Water heats up and cools down more slowly than land
- Earth reradiates solar energy back into the atmosphere at larger wavelengths.
Conduction- transfer of energy that occurs when molecules collide
- Energy is transferred from surface to lowest layer of atmosphere.
- Substances must be in contact with each other
- Convection- transfer of energy by flow of heated substance. Similar to the Sun and ocean.
Temperature vs Heat
Temperature: how rapidly or slowly molecules move around (Kinetic Energy). Used to measure and interpret energy.
Heat: transfer of energy
-flow of heat from an object of higher temperature to an object of low temperature.
-Transfer of energy that fuels the atmospheric processes.
Temperature- Fahrenheit or Celsius
Fahrenheit = 1.8 x Celsius + 32.0
Celsius = (Fahrenheit-32.0)/1.8
Kelvin-
- Zero Degrees Kelvin= -523° F
- Lowest possible temperature-no motion
Dew Point- (condensation temperature)
- constant pressure, cooler temperature to reach saturation
- saturation-air holds as much water vapor as it possible can
- condensation- gas to liquid
ex. Water changes state to fall as rain
-Temperature decrease in troposphere with increasing distance from surface
- Individual air masses can be warmer or cooler and wetter or drier than air around it.
- Lifted Condensation level- clouds begin to form-base of clouds
Air Pressure/Density/Temperature:
Know table 11-2 pg. 280
- Pressure decreases with height
- Density- number of particles of air occupying a particular space
- Temperature varies according to the ratio of pressure to density
- Temperature Inversion- cool on surface warm above-pollution trapped
Wind & Relative Humidity
- Wind- imbalance between air masses-movement from high pressure to low pressure.
- Humidity-water vapor
- Relative humidity-how much air can hold-varies with temperature-warm air more moisture than cool
Cloud Formation
• Form when warm, moist air rises, expands and cools in convection current
• Condensation nuclei-small particles in the atmosphere around which cloud droplets can form.
• Air reaches its dew point, the water vapor in the air condenses around nuclei
Orographic Lifting
• Clouds form when warm moist air is forced to rise over a mountain
• When two air masses of different temperatures meet
Stability: ability of an air mass to resist rising. Cooling air resists rising-it is stable.
Latent Heat: condensation-heat is released. Energy is stored in water vapor and released when condensation occurs. Stored energy is called Latent Heat