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

Troposphere

0-12 km (9 to 16 km)
Lower atmosphere
Contains:

Tropopause

approx. 12 km
Varies in elevation with seasons and latitude
Level at which temperature stops decreasing and begins increasing

Stratosphere

14 - 50 km
High altitude air mass
Contains:

Mesosphere

50 - 80 km
Temperature decreases with higher elevations

Thermosphere

80+ km
Extremely rarified air
Temperatures increase to more than 1000°C

Ionosphere

80 - 400 km
Electrically charged layer of ionized Nitrogen and Oxygen
Created by shortwave solar radiation

Auroras

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

Increased elevation results in decreased air density
Less air means less insulation
Radiation is lost more readily.
Less air means more intense insolation

Temperature Inversion

Temperature increases with increasing elevation.
Occurs when:

Annual Temperature Cycle

Temperatures vary annually
Based on seasonal amounts of insolation (axial tilt)

Land vs. Water Temperatures

Coastal areas: Generally cooler than inland areas
Lower annual and daily variations

Four Thermal Properties

1 - Penetration:

2 - Specific Heat:

3 - Convection:

4 - Evaporation:

Inland vs. Coastal Temperatures

Coastal areas:
Inland areas:

Surface Temperature Variations

Air temperature over different surfaces:
Dark surfaces:
Light surfaces:

Urban Areas vs. Rural Areas

Urban Heat Island: warmer temperatures
Dark buildings, asphalt, water drained beneath the surface, air conditioners and engines
Rural Areas: cooler temperatures
Soil, vegetation, moisture in the soil