Atmosphere Contents

4. Energy Budgets

Conclusion

The sun emits a more or less constant energy but the input at the Earth's surface varies owing to seasonal, diurnal and stochastic factors. The immediate characteristics of the Earth's atmosphere varies with the amount and spectral composition of solar radiation reaching the Earth's surface. The spatial differences in heating of the oceans and the atmosphere generate the climatic climaxes found on Earth. The heating of the Earth's surface causes it to emit long wave radiation which becomes trapped in the atmosphere creating global warming. Anthropogenic activity is contributing to this phenomenon by increasing the amount of carbon dioxide (and other greenhouse gases) present in the atmosphere. This is augmenting the various natural processes of climate change: variations in the Earth's orbital characteristics, changes in the amounts of carbon dioxide from the oceans, volcanic eruptions, and variations in solar output.

Questions and answers

1.Assuming a solar constant, why is there not a theoretically uniform energy input to each point of the Earth's surface?

question 1 answers

2.What wavelength of radiation does the Earth emit, and why?

question 2 answers

3.How does a CO2 enriched atmosphere contribute to global warming?

question 3 answers

4.Name three common greenhouse gases.

question 4 answers

5.What is albedo?

question 5 answers

6.i) What is a black body, ii) What is a white body, and,
iii) Do they exist?

question 6 answers

7.What limited factors are responsible for climate change?

question 7 answers

8.What impact do the oceans have on atmospheric carbon dioxide?

question 8 answers

9.How do volcanic eruptions affect short term climate change?

question 9 answers

10.Which two large volcanic eruptions in the last century have had
an effect on climate?

question 10 answers

11.What are sunspots?

question 11 answers

Question 1 answer

Although there is an output constant from the sun, the input at the Earth's surface per unit area is markedly different as the Earth is not flat. Also orbital forcing, and variation with season and time of day will also affect the input.

Question 2 answer

The relatively cool Earth emits longwave radiation. This is because the wavelength of radiation emitted by an object is inversely related to the temperature of the body. Energy from the sun by way of contrast, is short-wave radiation.

Question 3 answer

Longer wavelength radiation, emitted by the Earth, is trapped by the CO2 enriched atmosphere.

Question 4 answer

Answers include:
- water vapour (especially effective in a moist atmosphere);
- carbon dioxide;
- methane;
- ozone;
- chlorofluorocarbons (CFCs)

Question 5 answer

Albedo is the proportion of the reflected solar energy (from the atmosphere, from clouds and from objects on the Earth's surface) to the incident energy.

Question 6 answer

i) Black Body = Perfect absorber of radiation
ii) White Body = Perfect reflector of light
iii) They are theoretical bodies; in reality everything absorbs and
reflects as if it is a different shade of grey

Question 7 answer

Answers include:
- variations in the Earth's orbital characteristics
- atmospheric carbon dioxide variations
- volcanic eruptions
- variations in the solar output

Question 8 answer

The oceans are a major store of carbon dioxide, controlling its
movement to and from the atmosphere. The amount in the
oceans is a function of temperature. It is released from the oceans
when global temperatures become warmer and absorbed when
temperatures are cooler.

Question 9 answer

Volcanoes eject large quantities of sulfur dioxide into the stratosphere which reacts with water vapour to form a dense optically bright haze layer. This reduces the atmospheric transmission of some of the sun's incoming radiation.

Question 10 answer

El Chichon, Mexico in April 1982
Mount Pinatubo, Philippines in June 1991

Question 11 answer

Sunspots are magnetic storms that are dark, cooler areas on the sun's surface, with the number and size of sunspots having a cyclical pattern reaching a maximum every 11, 90 and 180 years.