ATM S 211: Climate and Climate Change Autumn 1999
D.L. Hartmann Sample Questions for Final Examination
Final, Friday, 10 December 1999, 8:30-10:20, Bring paper, calculator, pencils
1.0 Climate, the Earth System, and Human Activities (See Ch 11 of notes.)
1. Why does biomass decrease rapidly with increasing tropic level in an ecosystem? (11)
2. The amount of mass in the land biosphere is estimated to be around 2,000 Gigatonnes C. The global total rate of production of biomass by photosynbtheis is estimated to be around 100 Gigatonnes C per year. What is the mean residence time of carbon in the land biosphere?
4. What is the time scale for the tectonic recycling path? How is this time scale estimated?
5. What are the energy sources for the tectonic and the biological recycling paths?
6. Over the period from about 1700-1900AD has the human population growth been exponential? Explain why or why not. (11)
7. Briefly describe the theory of demographic transition. What experience is it based on? (11)
8. If demographic transition theory is correct, what problems does it pose for sustainability of renewable biotic resources. (11)
9. What information would you need to estimate Net Primary Productivity? How could you get this information? (11)
10. Summarize the arguments of the neo-Malthusians. What would their opponents say in answer to this argument? (11)
11. Describe the relationships among population growth, economic growth and energy consumption. (11)
12. Can the historic association between energy consumption growth and economic growth be broken? What would be necessary to break it? (11)
13. Do you think equity (fairness) is a central issue for sustainability of renewable resources? (11)
2.0 Energy, Radiation and Heat Balance
14. 100 kg of water flows over a dam 100 meters high. How much potential energy is released(give your answer in Joules). If the flow takes place in 2 seconds, how many Watts of power are provided? If the efficiency of the electrial power system using this energy release is 60%, what is the electrical power output?
15. You bring a pot of water to boil on the stove, then boil all the water away. Which takes longer, bringing the water to a boil from room temperature, or boiling all the water away? Explain your answer.
16. Explain why a supply of energy is needed to convert carbon dioxide and water into reduced organic matter and oxygen.
17. At what rate would coal need to be supplied to provide the electricity needed by a city of 1 million people, if the average person uses energy at the rate of 3kiloWatts, the energy content of coal is 29x10
18. Explain how ice-albedo feedback can increase the size of the warming of climate in response to an increased solar constant.
19. Explain water vapor feedback.
20. If the atmosphere filled with smoke that covered the planet and absorbed most radiation in the atmosphere, but the global albedo remained at 0.3, how do you think the surface temperature would change?
21. If the solar constant at Earth is 1380 Wm
-2, and Jupiter is five times as far from the Sun as Earth, what is the solar constant at Jupiter?22. Where does the daily average insolation reach its largest value, at the equator or at the poles? Explain.
23. Explain the natural greenhouse effect to a friend. In what ways is the atmospheric greenhouse effect like a garden greenhouse, and it what ways is this analogy misleading?
24. What is the atmospheric window? In what ways is it important?
25. Explain the relationships among the latent heats of vaporization, melting and sublimation.
26. What is specific heat?
27. Explain the differences between the radiative emissions of a body at 288K and one at 6000K. What are the kinds of radiation that are emitted from each body, and how much energy to you get from each.
28. Why does the insolation peak twice a year at the equator?
29. What would be the emission temperature of Mars, if Mars was twice as far from the sun as Earth and its albedo was 16%.
30. What would be the emission temperature of Earth, if the solar constant was doubled and the albedo of Earth was increased from 0.3 to 0.65?
31. If the sun was 30% less powerful 3 billion years ago, how could the Earth’s surface have remained unfrozen?
32. Explain the difference between emission and reflection. Why is the difference important for understanding the greenhouse effect?
33. Describe the two most important properties of the atmosphere that give us the natural greenhouse effect that warms the surface of Earth.
34. You are designing a satellite to orbit Earth and observe the weather. The instruments require 1 kilowatt of power, and the efficiency of the photovoltaic converters on the solar panel is 10%. What must be the area of the solar panel, if you can direct it so that its surface is always perpendicular to the sun’s rays?
36. Explain in scientific terms, why you might want to tilt a solar collector by lifting up its northern side.
37. Why are the poles colder than the equator?
38. The solar constant at Earth is 1380 W m-2, and the global average albedo is currently 0.3. The present greenhouse effect adds about 33K to the average surface temperature over what the average surface temperature would be if there was no atmosphere. Suppose the Earth was ice-covered and had an albedo of 0.7. What would the average surface temperature be, if the greenhouse effect remained the same? Would you expect the greenhouse effect to remain the same? Why?
39. Explain how the "greenhouse effect" works for a friend who has not taken an atmospheric science course. What is misleading about the use of the term "greenhouse effect"?
42. Suppose the greenhouse effect reduces the net longwave radiation lost by the surface of the Earth. Assuming no corresponding change in the solar energy components, what other changes would you expect to see in the surface energy budget in order to restore balance? How would these changes affect the hydrological cycle?
43. Over an annual cycle, there is a net surplus in Earth's radiative budget near the equator and net deficits near the poles. How does the climate system balance the surplus and deficits?
3.0 Atmospheric Composition and Climate
44. When did the level of oxygen in the atmosphere reach current levels?
45. Explain how animals at the bottom of the ocean that eat detritus (fallen biomass) can help to control the level of oxygen in the atmosphere through a negative feedback process.
46. Explain why tectonic recycling is important for life on Earth to be sustained?
47. Why does the lowest part of the atmosphere have temperature maxima at the ground and again up around 50 kilometers altitude?
48. Is there a habitable zone in which life like Earth's can exist, located at some distance from a star? What determines how far from the star this habitable distance would be?
51. If photosynthetic life had not developed on Earth, how do you think our atmosphere and climate would be different?
52. A huge amount of CO
53. Why will burning all the available coal have a huge effect on the CO
2 content of the atmosphere, but a negligible effect on the O2 content of the atmosphere?54. Why are there not more noble gases like Neon and Krypton in the atmosphere?
55. What would be the emission temperature of Earth, if the solar constant was doubled and the albedo of Earth was increased from 0.3 to 0.65?
56. How is limestone formed and why is this important for climate?
57. Why does Venus not have oceans? How did forming oceans make Earth’s atmosphere so different from that of Venus?
60. Mean residence time of water in the deep ocean is estimated to be about 1000 years from 14C dating. The amount of C stored in the ocean, mainly in the form of bicarbonate ion, is estimated to be about 40,000 gigatonnes. What is the approximate rate of carbon transfer from the surface layers of the ocean to the deep ocean via the overturning of the thermohaline circulation.
61. What processes have been responsible for buildup of oxygen in the atmosphere over geological history? What processes regulate the concentration of oxygen in the atmosphere at the present time?
62. As we continue to burn fossil fuels over the next century or two, do you think that loss of oxygen from the atmosphere a major concern? Why or why not?
64. What role does the weathering of calcium rich rocks play in the cycle of carbon?
66. Compare the climatic conditions at the surfaces of Mars, Venus, and Earth. How does the composition of Earth's atmosphere differ from those of Mars and Venus? What factors in the evolutionary history of these planets account for these composition differences?
67. Why is there no liquid water on either Mars or Venus at the present time?
4.0 Atmospheric and Oceanic Circulation and Climate
68. Explain how the principle of angular momentum conservation affects the shape of the Hadley circulation.
69. If the Hadley circulation were to weaken, how would this affect the distribution of precipitation in the tropics and subtropics?
70. What is meant by a monsoon circulation? Why are some monsoons wet and others dry? Why is the strongest monsoon circulation of the globe associated with the Asian continent?
72. Describe the coupling between atmospheric circulation and circulation of the oceanic mixed layer in the Walker circulation. Why are sea surface temperatures colder in the eastern than the western equatorial Pacific Ocean? Why are low clouds and dry conditions generally present near the eastern end of the Walker circulation while deep convective clouds and heavy precipitation are generally present near the western end?
75. Explain why early Spanish galleons traveled to the New World on a more southerly route than their return.
76. How does the distribution of precipitation and evaporation at the surface of the Atlantic Ocean influence the strength of the thermohaline circulation?
77. Describe one source of information about the pattern of water circulation in the deep ocean. How do we know the overturning time of water in the deep ocean?
78. Explain the relationship between the oceanic anticyclones associated with the Hadley circulation and the major current gyres of the world.
79. Why is the climate of western Europe generally milder than the climate of western north America at the same latitudes? (Note that Britain and most of France are at the latitude of British Columbia).
80. Why do the current systems of the northern Indian ocean reverse seasonally?
81. Where would you expect maximum upwelling to occur along the coasts of the Indian ocean in summer?
83. In what direction (poleward or equatorward) does the Hadley circulation transport energy of the following kinds? 1) Sensible heat, 2) Latent heat, 3) Potential energy, and 4) Moist static energy?
84. Why are so many deserts located in the latitude belts between 20 and 30š?
85. Why does it rain heavily in India during summer and hardly at all during winter. Explain the circulations that develop and what drives them.
86. You are in charge of the annual company picnic and softball tournament. If your objective is minimum rainfall, on what day of the year should you schedule it if it is to be held in: a) Seattle or b) Orlando, Florida? Why?
87. In what direction do the westerly winds in midlatitudes drive the surface water of the North Atlantic? How does this water get back to its place of origin?
88. Where are the two geographic locations where ocean deep water is formed and how is deep water formed there? How do we know this? What does it take to make water dense enough to sink to the bottom of the ocean? How do the deep water formation mechanisms in these two regions differ?
89. Where does the deep water go after it sinks to the bottom of the North Atlantic? Where does it come up again?
90. Why are coastal and high latitude oceans more productive than the subtropical gyre regions?
91. What is the thermohaline circulation? Why is it called this?
93. Explain why Seattle has a dry summer and a wet winter?
94. In middle latitudes, why is land warmer than ocean surface in summer and colder than the ocean in winter?
95. Draw a surface weather map of a mature midlatitude cyclone and explain how it transports heat and moisture poleward.
96. Draw a latitude (0-90N) versus height (0-20km) cross section showing the contours of zonal wind speed. Identify the easterlies, westerlies and the subtropical jet stream.
98. Why are the winds easterly equatorward of about 30š latitude?.
99. Southerly winds blow along the west coast of Australia. Describe the resulting ocean currents and sea surface temperature (SST) distribution.
100. Explain why SST is cold in the eastern Equatorial Pacific and warm in the western equatorial Pacific.
5.0 Water and Climate
101. Contrast the annual cycle of monthly precipitation in a) Seattle, b) Des Moines, Iowa, and c) Boston.
102. Why is the month of maximum precipitation October in Juneau and February in Los Angeles?
103. Why does Olympia (53 in) get more precipitation than Seattle (36 in), and both of these cities get more than Yakima (8 in).
104. Why do clouds form in rising air?
105. Why do evaporation and condensation represent a transfer of energy from surface to atmosphere?
107. The atmosphere holds about 25 kg of water in the form of vapor per square meter of surface area, on the average. The global average precipitation rate is about 1 meter per year. The density of water is about 1000 kg m-3 . Use these numbers to estimate the mean residence time of water vapor in the atmosphere.
110. Describe how surface moisture availability, surface temperature, and surface wind speed affect the local surface evaporation.
112. Why does ice float? Write a short paragraph speculating (intelligently) on the ways climate would be different if ice sank instead of floated?
113. Consider the Olympic west slopes (A), Puget Sound (B), the Cascade west slopes (C), and the Columbia River Valley of central Washington (D). List these locations in order of decreasing annual rainfall (from largest to smallest).
114. What is a Noonatak?
6.0 The History of Climate
115. Why would the period 30,000-15,000 years ago be a good time for the first Americans to have arrived from Asia?
116. Give two examples of proxy data for interpreting past climates, describe the advantages and disadvantages of each, and give the time frames for which each data type provides useful information.
118. Briefly describe the variations in global mean temperature over the Pleistocence Period (the past 1-2 million years or so). What is the evidence for these variations?
119. Describe the variations in global mean temperature and atmospheric composition over the past 140,000 years. What is the evidence for these temperature and composition variations?
122. Explain why you can infer the amount of land ice in the past from the
7.0 Natural Forcing of Climate
123. Describe the distinction between "weather" and "climate". What information would you require to adequately define the climate of a specific region?
124. Why is the water along the equator in the eastern Pacific ocean cold?
125. How does the distribution of water temperature along the equator change during the warm phase of the ENSO cycle? Why does it change in this way?
127. What is the evidence that Earth's orbital variations have triggered Pleistocene ice ages? Describe a plausible feedback mechanism in the triggering.
129. Explain the Milankovitch orbital parameter theory for ice ages. What is supposed to determine ice ages and how is this related to the orbital parameters? What are the key orbital parameters?
130. What are the critical characteristics of a volcanic eruption that determine its effect on climate and why?
131. Why was 1993 colder than 1990 or 1995?
132. Explain the sequence of events that leads to a warm event in the equatorial Pacific. How do La Niña conditions lead to El Niño conditions?
133. It is said that a meteorite hit the Earth 65 million years ago and killed off more than half of the species living at that time. Describe the evidence for this. Where did the meteor hit and at what angle and how do we know this?
134. What is the Dust Bowl, where did it occur and what caused it?
135. What are the three key orbital parameters and how do they influence climate? With what periods do they vary?
8.0 Greenhouse Warming
136. Give three reasons why CFCs can provide significant greenhouse gas forcing of climate even when they are present in tiny abundances of parts per billion by volume.
138. How can clouds provide either positive or negative feedbacks in the climate system?
139. Give some reason(s) why the rate of increase of temperature in global warming might be as serious a problem (or even more serious) than the magnitude of the warming itself.
141. What is the primary naturally occurring greenhouse gas? What is the gas that humans are increasing through their actions that is causing the most global warming?
142. Summarize the evidence supporting the statement that the anthropogenic greenhouse warming of climate has arrived.
9. Thinning of the Ozone Layer
143. In what latitude range (tropics, mid-latitudes, polar latitudes) is the thickness of the stratospheric ozone shield largest? At which latitudes is it least? At what seasons is it largest?
144. What is "UV-B radiation"? What specific human health effects would be expected to arise from an increase in UB-B radiation? How would an increase in UV-B radiation be likely to affect the marine biosphere? How do stratospheric ozone changes affect UV-B radiation? How does UV-B radiation depend on latitude and season?
145. Consider the following gas phase chemical reactions:
NO + O3
NO2 + O
Æ NO + O2.Why is this pair of reactions referred to as a catalytic cycle? What is the net reaction? What is (are) the catalyst(s) in this cycle?
149. Briefly explain how stratospheric ozone can be "good" for the biosphere while tropospheric ozone is "bad" for the biosphere.
150. What is the largest source of stratospheric chlorine atoms?
152. Why does free chlorine normally not catalytically destroy ozone in the lower stratosphere? What special circumstances allow chlorine atoms to efficiently destroy ozone in the lower stratosphere?
155. Critique the claim that CFCs do not reach the stratosphere because CFC molecules are heavier than air molecules.
162. Why is acid rain a much more serious problem in the eastern U.S. than in the western U.S.?
163. How can industrial sulfur dioxide emissions influence climate? How do the potential climate effects of these emissions complicate the problem of identifying a signature of increasing greenhouse gases in climatic records?
164. Why are HCFCs expected to destroy stratospheric ozone less effectively than CFCs? Which gases are expected to contribute most to increasing greenhouse effect - CFCs or HCFCs? Why?
10. Our Energy Future
166. Why is fossil fuel energy so cheap?
167. Give an example of an "externality" associated with production and/or consumption of a fossil fuel. State clearly what is meant by an externality.
168. How is the burden of the externality you identified in question 167 distributed between those who derive the benefits from the fuel consumption and those who do not? Do you consider this to be an equity issue? Explain why or why not.
169. Write a short paragraph describing the conditions under which deposits of petroleum are formed. What climatic and geological conditions were favorable for the formation of petroleum deposits? What conditions favored formation of natural gas deposits?
170. Write a paragraph on the future petroleum supply prospects for the U.S. describing the relative roles of domestic and imported petroleum, the likely trends in distribution of providers of imported petroleum, and some plausible economic, political, and international security implications of these anticipated trends.
171. Use the concept of energy profit ratio to explain why fossil fuels have played such a major role in the economic development of the modern world.
173. Why does petroleum production in a country or region typically have a rapid increase in production followed by a rapid decline?
175. Explain why, in the long-run, the problem of global warming is a problem of coal much more than it is a problem of petroleum or natural gas.