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 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 Inversion

Temperature increases with increasing elevation.
Occurs when:

Annual Temperature Cycle

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

8 Controls on Atmospheric Temperature

1.
2.
3.
4.
5.
6.

7. Four Thermal Properties of Land vs Water

Penetration
Specific Heat
Convection
Evaporation

Inland areas:
Coastal areas:

8. Cloud/Ground Cover: Albedo

Clear sky days are warmer than cloudy days
Clear sky nights are cooler than cloudy nights
Why?

Impact of cloud cover on annual temp.
Air above dark surfaces will be:
Air above light surfaces will be:

Urban Heat Island

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