Atmosphere Contents

3. Energy Variation

Conclusion

A number of factors influence the amount of solar radiation received by the Earth. These include the distance from the sun, the shape of the Earth's orbit, the distance from the equator, the Earth's obliquity and precession. Precession also alters the distribution of radiation across the Earth's surface. However, notwithstanding these variations, the average temperature of the Earth is fairly constant with surpluses of radiation at the equator balanced by deficits at the poles. Redistribution of this energy is continually occurring via transportation of heat through the general circulation of the atmosphere and oceans.

Question and answers

1.On what periodicity does orbital forcing occur?

question 1 answers

2.How does eccentricity affect the radiation reaching the surface?

question 2 answers

3.On what periodicity do changes in axial tilt occur?

question 3 answers

4.How does obliquity affect the radiation reaching the surface?

question 4 answers

5. On what periodicity does precession (or axial "wobble") occur?

question 5 answers

6.How is energy redistributed between surplus (equatorial) and deficit (polar, high altitude) regions?

question 6 answers

7.How are imbalances overcome in the amount of incoming energy from the sun and the amount outgoing from the Earth, and ii) At what latitudes is there a balance?

question 7 answers

Answer 1:

Orbital forcing (Eccentricity) occurs on a 100,000 year cycle.

Answer 2:

Variations in the orbital ellipse are responsible for changes in incoming solar radiation. In the present orbit the Earth is closest to the sun in late December and farthest from the sun in late June.

Answer 3:

The tilt of the axis varies between 22o and 24.5o over a period of 41,000 years. This and the spherical shape of the Earth alter the intensity of solar radiation reaching different global latitudes i.e. redistribute energy.

Answer 4:

The tilt of the axis vary between 22o and 24.5o . This and the spherical shape of the Earth alter the intensity of solar radiation reaching different global latitudes i.e. redistribute energy.

Answer 5:

Precession ("wobble") occurs on a cycle of approximately 23,000 years.

Answer 6:

Weather and currents represent the Earth's attempt to redistribute energy and eradicate geographical anomalies. They convert absorbed solar energy into kinetic and potential energy which generate motion as wind, waves glaciers and also rivers.

Answer 7:

i) Heat is being lost from the tropics and transported to the poles
within the general circulation of both the atmosphere and the
oceans. The transfer of heat varies according to latitude and
season.
ii) Only at around 37° north and south is there a balance.