HPU NCS2200 earth science for elementary education majors summer 2014 online class function and structure of the atmosphere part 2

1. Heating the atmosphere
• Solar energy (UV radiation) is absorbed
– Darker objects absorb more radiation than
lighter objects which reflect radiation
• Albedo – ability to reflect light radiation
• Absorbed radiation converted to heat
(infrared radiation)
• Heat radiates off object and warms
surrounding air

2. Earth’s Warming Mechanism
• Greenhouse effect
– Natural and Essential Process
– Global Warming is a DESIRED result of the
greenhouse effect
– Without this process the earth would be
uninhabitable
• An INCREASED RATE of Global Warming could
cause global climate consequences

3. Greenhouse gases
• Contained in the upper troposphere
– Carbon dioxide (CO2)
– Water Vapor (H2O)
– Methane (CH4)
– Nitrogen Oxide (N2O)
• Form a barrier that reflects infrared
radiation and traps it

4. Greenhouse Effect
UV radiation (short-fast
wavelengths) from sun
penetrates atmosphere
UV Radiation is absorbed
by the earth surfaces
UV Radiation is converted
to heat (infrared radiation –
long-slow wavelengths)
Infrared radiation rises
into the atmosphere
Long slow wavelengths
cannot penetrate the
greenhouse gases in
atmosphere
Heat is trapped in
troposphere warming the
earth’s air and surface.

5. Circulation of air
• Recall Convection
– Transfer of heat
through a fluid
– Energy warms the air
– density decreases
– Warm air rises
– As air rises it cools –
density increases
– Cool air falls
– repeats

6. Atmospheric circulation
• Uneven heating of the
earth’s surface
causes temperature
differences
• Temperature
differences create
pressure differences
• Pressure differences
cause air to move
• High pressure air
moves and pushes
low pressure air –
WIND is generated

7. Coriolis effect
• Non Rotating Earth model
– Winds would blow only from north pole to
equator
• Rotating Earth model
– Rotation of earth creates Coriolis Effect
• Deflection of actions due to earth’s rotation
• Northern Hemisphere rotate to the right
• Southern Hemisphere rotates to the left
– Creates Atmospheric circulation cells and wind
belts

8. Coriolis efffect

9. Wind Belts
Three major wind belts created by Coriolis effect
– 60 – 90 degrees latitude Polar Easterlies – winds blow FROM the
east
– 30 – 60 degrees latitude Westerlies – winds blow FROM the west
– 0 – 30 degrees latitude (equator) Trade Winds – blow from east to
west

10. The
convection
cells
redistribute
heat and
moisture
creating
the climate
regions
north and
south
of the
equator.