Energy Balance and Circulation Systems

2 of 12 Importance Energy from Sun (Energy Budget) –“Drives” Earth’s Atmosphere  Creates Circulation Circulation Systems –Create Weather and Climate

3 of 12 Solar Radiation Entering the Atmosphere Absorbed by gases and clouds – goes to heating (19%) Scattered and Reflected by Gas Molecules, Clouds, Aerosols, and the Earth’s surface (30%) About 51%

4 of 12 Albedo Percent of radiation returning from a surface compared to amount of radiation initially striking the surface Represents the reflectivity of a surface Varies depending upon surface Earth and atmosphere have a combined albedo of 30%

5 of 12 Albedo

6 of 12 Earth’s Energy Balance Earth’s overall average equilibrium temperature changes only slightly from year to year. A balance exists between incoming solar energy (shortwave radiation) and outgoing energy from Earth to space (longwave radiation).

7 of 12 Energy received at the surface depends on: 1) Sun angle with respect to surface. 2) Path of solar radiation through the atmosphere.

8 of 12 Same Amount of Energy, Larger Area

9 of 12 More direct radiation at Equator than at Poles –More energy at lower latitudes

10 of 12 The Energy to Drive the Atmosphere Atmospheric and ocean circulations redistribute energy from latitudes with a surplus into latitudes with a deficit. Unequal distribution in incoming solar radiation (red) and outgoing Earth’s radiation (blue)

11 of 12 Atmospheric Circulations

12 of 12 Rainforests near Equator Deserts near 30 o North and South

13 of 12 Atmospheric Circulations Why the easterlies and westerlies?

14 of 12 Coriolis Force An “apparent” force that is due to the rotation of the earth. Winds are deflected to the right in the Northern Hemisphere. Winds are deflected to the left in the Southern Hemisphere.

15 of 12 Coriolis Force Deflection Greatest deviation at the poles. Zero deviation at the equator.

16 of 12 Atmospheric Circulations Why the easterlies and westerlies?

17 of 12 Seasonal Changes January July

18 of 12 Ocean circulation

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20 of 12 Without greenhouse gases, the average surface temperature of the Earth would be –18° C No greenhouse gases (only permanent gases) The current atmosphere (with greenhouse gases) 33° C difference

21 of 12 The other extreme… CO 2 rich CO 2 poor Biotic Atmosphere Most of the early CO 2 is stored as calcium carbonate (CaCO 3 ) or limestone.

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