Environmental Science 102
Temperature Structure of the Atmosphere
Temperature and Elevation
Lower atmosphere: increased elevation = decreased temp.
Temperature decreases at constant rate
Lapse Rate of 6.4°C/1000 meters
Structure of the Atmosphere
0-12 km (9 to 16 km)
approx. 12 km
Varies in elevation with seasons and latitude
Level at which temperature stops decreasing and begins increasing
14 - 50 km
High altitude air mass
50 - 80 km
Temperature decreases with higher elevations
Extremely rarified air
Temperatures increase to more than 1000°C
80 - 400 km
Electrically charged layer of ionized Nitrogen and Oxygen
Created by shortwave solar radiation
Solar radiation and charged particles of the solar wind follow the Earth’s magnetic force lines and enter the atmosphere at the poles.
Air Density and Pressure
Increased elevation results in decreased air density and lower air pressure.
Less air means less insulation
Radiation is lost more readily.
Less air means more intense insolation
Temperature increases with increasing elevation.
Annual Temperature Cycle
Temperatures vary annually
Based on seasonal amounts of insolation (axial tilt)
8 Controls on Atmospheric Temperature
7. Four Thermal Properties of Land vs Water
8. Cloud/Ground Cover: Albedo
Clear sky days are warmer than cloudy days
Clear sky nights are cooler than cloudy nights
Impact of cloud cover on annual temp.
Air above dark surfaces will be:
Air above light surfaces will be:
Urban Heat Island