Elemental Geosystems, 5th Edition - Chapter 3

3 Atmospheric Energy and Global Temperatures Earth's biosphere pulses daily, weekly, and yearly with flows of energy. Think for a moment of the annual pace of your own life, your wardrobe, gardens, and lifestyle activities—all reflect shifting seasonal energy patterns. Thus begins the culmination of the passage of energy from the Sun, across space, to the top of the atmosphere, down through the layers of the atmosphere to Earth's surface. This entire process should be thought of as a vast flow-system with energy cascading through fluid Earth systems. The beginning lecture can mention this flow-system and the journey of the past chapter. Air temperature has a remarkable influence upon our lives, both at the microlevel and at the macrolevel. A variety of temperature regimes worldwide affect entire lifestyles, cultures, decision-making, and resources spent. Global temperature patterns presently are changing in a warming trend that is affecting us all and is the subject of much scientific, geographic, and political interest. Our bodies sense temperature and subjectively judge comfort, reacting to changing temperatures with predictable responses. This chapter presents principles and concepts that are synthesized on the January and July temperature maps, and on the annual range of temperature map. The chapter then relates these temperature patterns and concepts directly to the student with a discussion of apparent temperatures—the wind chill and heat index charts. Focus Study 3.2 introduces some essential temperature concepts to begin our study of world temperatures. We take a look at how Earth's temperature system appears to be in a state of dynamic change as concerns about global warming and potential episodes of global cooling are discussed in Chapter 7. An overview of the latest scientific findings concerning global climate change is in that chapter. Outline Headings and Key Terms The first-, second-, and third-order headings that divide Chapter 3 serve as an outline for your notes and studies. The key terms and concepts that appear boldface in the text are listed here under their appropriate heading in bold italics. All these highlighted terms appear in the text glossary. Note the check-off box () so you can mark your progress as you master each concept. Your students have this same outline in their Student Study Guide. The icon indicates that there is an accompanying animation or other resource on the CD. The outline headings for Chapter 3: Energy Essentials Global Albedo Values Global Shortwave Radiation Global Net Radiation Global Latent Heat Flux Values Global Sensible Heat Energy Pathways and Principles transmission Insolation Input Scattering (Diffuse Radiation) scattering diffuse radiation Refraction refraction Albedo and Reflection albedo reflection Clouds and Atmosphere's Albedo cloud-albedo forcing cloud-greenhouse forcing Absorption absorption Conduction, Convection, and Advection conduction convection advection The Greenhouse Effect and Atmospheric Warming greenhouse effect Clouds and Earth's “Greenhouse” Earth–Atmosphere Radiation Balance Earth–Atmosphere Energy Balance Global Warming, Climate Change Energy at Earth's Surface Balance Daily Radiation Patterns Simplified Surface Energy Balance microclimatology Net Radiation net radiation (NET R) Temperature Concepts and Controls temperature Temperature Scales and Measures Measuring Temperature Principal Temperature Controls Latitude Altitude Cloud Cover Land–Water Heating Differences land–water heating differences Evaporation Transparency transparency Specific Heat specific heat Movement Ocean Currents and Sea-Surface Temperatures Gulf Stream Summary of Marine Effects vs. Continental Effects marine effect continental effect Earth's Temperature Patterns Global Sea-Surface Temperatures Global Surface Temperatures, Land and Ocean isotherm January Temperature Map thermal equator July Temperature Map Annual Range of Temperatures The Urban Environment urban heat island dust dome Summary and Review News Report and Focus Studies Focus Study 3.1: Solar Energy Collection and Concentration Focus Study 3.2: Air Temperature and the Human Body High Latitude Connection 3.1: Overview of Temperature Trends in the Polar Regions The URLs related to this chapter of Elemental Geosystems can be found at http://www.prenticehall.com/christopherson Key Learning Concepts After reading the chapter and using this study guide, the student should be able to: • Identify the pathways of solar energy through the troposphere to Earth’s surface: transmission, refraction, albedo (reflectivity), scattering, diffuse radiation, conduction, convection, and advection. • Describe the greenhouse effect, and the patterns of global net radiation and surface energy balances. • Review the temperature concepts and temperature controls that produce global temperature patterns. • Interpret the pattern of Earth’s temperatures for January and July and annual temperature ranges. • Contrast wind chill and heat index and determine human response to these apparent temperature effects. • Portray typical urban heat island conditions and contrast the microclimatology of urban areas with that of surrounding rural environments. Annotated Chapter Review Questions • Identify the pathways of solar energy through the troposphere to Earth's surface: transmission, refraction, albedo (reflectivity), scattering, diffuse radiation, conduction, convection, and advection. 1. Diagram a simple energy balance for the troposphere. Label each shortwave and longwave component and the directional aspects of related flows. The keys are Figures 3.1 and 3.10, which illustrate the Earth-atmosphere energy balance, which is referred to at the beginning of this section. This figure is reproduced in outline form without labels in the Student Study Guide. Students are instructed to fill in information, add labels, and even color in the illustrations as they move along through this discussion. If you use a chalkboard, this is an opportunity to draw the energy budget along with the students as you lecture. The illustration is also included in the overhead transparency packet with this chapter. 2. Define refraction. How is it related to daylength? To a rainbow? To the beautiful colors of a sunset? When insolation enters the atmosphere, it passes from one medium to another (from virtually empty space to atmospheric gas) and is subject to a bending action called refraction. In the same way, a crystal or prism refracts light passing through it, bending different wavelengths to different degrees, separating the light into its component colors to display the spectrum. A rainbow (Figure 3.3) is created when visible light passes through myriad raindrops and is refracted and reflected toward the observer at a precise angle. Another example of refraction is a mirage, an image that appears near the horizon where light waves are refracted by layers of air of differing temperatures (densities) on a hot day. An interesting function of refraction is that it adds approximately eight minutes of daylight for us. The Sun's image is refracted in its passage from space through the atmosphere, and so, at sunrise, we see the Sun about four minutes before it actually peeks over the horizon. Similarly, at sunset, the Sun actually sets but its image is refracted from over the horizon for about four minutes afterward. To this day, modern science cannot predict the exact time of sunrise or sunset within these four minutes, because the degree of refraction continually varies with temperature, moisture, and pollutants. Notes on Sky Color. The principle known as Rayleigh scattering—named for English physicist Lord Rayleigh, who stated the principle in 1881—relates wavelength to the size of molecules or particles that cause the scattering. The general rule is the shorter the wavelength, the greater the scattering, and the longer the wavelength, the less the scattering. Shorter wavelengths of light are scattered by small gas molecules in the air. Thus, the shorter wavelengths of visible light, the blues and violets, are scattered the most and dominate the lower atmosphere. And because there are more blue than violet wavelengths in sunlight, a blue sky prevails. As the atmosphere thins with altitude, there are fewer molecules to scatter these shorter wavelengths, and the sky darkens. At 50 km, even though it may be daylight, the sky appears as at night and the stars become visible along with the Sun. 3. List several types of surfaces and their albedo values. Explain the differences among these surfaces. What determines the reflectivity of a surface? A portion of arriving energy bounces directly back to space without being converted into heat or performing any work. This returned energy is called reflection, and it applies to both visible and ultraviolet light. The reflective quality of a surface is its albedo, or the relationship of reflected to incoming insolation expressed as a percentage (In Figure 3.6). In terms of visible wavelengths, darker colors have lower albedos, and lighter colors have higher albedos. On water surfaces, the angle of the solar beam also affects albedo values; lower angles produce a greater reflection than do higher angles. In addition, smooth surfaces increase albedo, whereas rougher surfaces reduce it. See Figure 3.6 for specific values. 4. Define the concepts transmission, absorption, diffuse radiation, conduction, and convection. See the Glossary section in the text and Figure 3.7 for illustration. • Describe the greenhouse effect, and the patterns of global net radiation and surface energy balances. 5. What are the similarities and differences between an actual greenhouse and the gaseous atmospheric greenhouse? Why is Earth's greenhouse changing? In the greenhouse analogy, the glass is transparent to shortwave insolation, allowing light to pass through to the soil, plants, and wood planks inside. The absorbed energy is then radiated as infrared energy back toward the glass, but the glass effectively traps the longer infrared wavelengths and warms the air inside the greenhouse. Thus, the glass allows the light in but does not allow the heated air out. In the atmosphere, the greenhouse analogy is not fully applicable because infrared radiation is not trapped as it is in a greenhouse. Rather, its passage to space is delayed as the heat is radiated and reradiated back and forth between Earth's surface and certain gases and particulates in the atmosphere. The present warming is associated with an increase in radiatively active greenhouse gases. This discussion is important to portions of the rest of the text relative to the greenhouse effect and global climate change. The operation of Earth's greenhouse sets the stage for the discussion of future temperature trends and global warming, and future climate patterns and consequences of climatic warming in Chapter 6, sea level changes in Chapter 13, the Antarctic ice sheet in Chapter 14, ecosystem stability and climate change in Chapter 16, and the summary overview comments in Chapter 17. The text author chose to present global change in this manner instead of in an isolated focus study because this present trend is so spatially pervasive through many of Earth's systems. We hope this integrated approach will assist the student in seeing the complex interconnections that link all Earth systems and the human population. 6. Generalize the pattern of global net radiation. How might this pattern drive the atmospheric weather machine? (See Figure 3.11.) In the equatorial zone, surpluses of energy dominate, for in those areas more energy is received than is lost. Sun angles there are high, with consistent daylength. However, deficits exist in the polar regions, where more energy is lost than gained. At the poles the Sun is extremely low in the sky, surfaces are light and reflective, and for six months during the year no insolation is received. This imbalance of net radiation from the equator to the poles drives the vast global circulation of energy and mass. Figure 3.11 summarizes the latitudinal distribution of net radiation. This completes a full cycle of discussion that began in Chapter 2 with energy measurements at the top of the atmosphere. This is the net radiation portrait of the entire Earth-atmosphere system. A useful analogy for the students could be some version of the following: Imagine that you are dealing with money instead of energy, so that at the equator there is the Tropical Branch Bank, and at the pole the Polar Branch Bank. You are in charge of accounts at both of these bank branches, and for reasons unknown to you, more deposits are made at the Tropical Branch than you are withdrawing. At the Polar Branch, you make more withdrawals than you do deposits. Fix in your mind that both accounts act as open-flow systems, with yourself in charge of the inputs and outputs. The resultant dollar amounts in your two accounts pose an interesting problem: one is full of surplus cash while the other account is in a deficit, with checks bouncing. Your solution? To balance your financial situation, you must transfer excess deposits from the surplus account to the deficit account. Of course this is what happens in the Earth-atmosphere system, with the transfer of energy and mass (water and water vapor). 7. In terms of surface energy balance, explain the term net radiation (NET R). Net radiation is the net all-wave radiation available at Earth's surface; it is the final outcome of the entire radiation balance process discussed in this chapter. Net radiation (NET R) is the balance of all radiation, shortwave (SW) and longwave (LW), at Earth's surface. As students travel about during the day (perhaps not as far afield as these sample stations), they can note the different surfaces and imagine each of the energy balance components. Ask them to consider the pathways for the expenditure of net radiation available at each surface: turbulent transfer, latent heat of evaporation, photosynthesis, conduction into the soil, or conduction and convection processes in bodies of water. And consider various alterations to those surfaces: clearing, paving, reforestation, and tilling. The students might speculate about what changes take place in the net radiation balance because of these alterations. As a contrasting example, work through the equation as if we were applying it to the lunar surface. The NET R at the surface of the Moon is totally expended for G. The surface increases in temperature to almost the boiling point of water and decreasing in temperature an equal amount below freezing in shadow or at night. An astronaut in a spacesuit will receive total G on his sun-facing side and total loss of G on his shady side as he stands in the direct sunlight. 8. What are the expenditure pathways for surface net radiation? What kind of work is accomplished? Output paths at the surface for the principal expenditures of net radiation from a nonvegetated surface include H (turbulent sensible heat transfer), LE (latent heat of evaporation), and G (ground heating and cooling). See bulleted items in the text chapter. 9. What is the role played by latent heat of evaporation in surface energy budgets? Latent heat refers to heat energy that becomes stored in water vapor as water evaporates. Large quantities of latent heat are absorbed into water vapor during its change of state from liquid to gas. Conversely, this heat is released in its change of state back to a liquid (see Chapter 5). Because the evaporation of water is the principal method of transferring and dissipating heat surpluses vertically into the atmosphere, latent heat is the dominant expenditure of Earth's entire NET R. Latent heat links Earth's energy and water (hydrologic) systems and for most landscapes is the key component in surface energy budgets. 10. Compare the daily surface energy balances of El Mirage, California, and Pitt Meadows, British Columbia. Explain the differences. El Mirage, California, at 35° N, is a hot desert location characterized by bare, dry soil with very little vegetation (Figure 3.14a). The summer day selected was clear, with a light wind in the late afternoon. El Mirage has little or no expenditure of energy for LE. With an absence of water and plants, most of the available radiant energy is dissipated as turbulent sensible heat, warming air and soil to high temperatures. The G component is higher in the morning, when winds are light and turbulent transfers are reduced. The NET R at this desert location is quite similar to that of midlatitude, vegetated, and moist Pitt Meadows, British Columbia (Figure 3.14b). The energy balance data for Pitt Meadows, at 49° N, are plotted for a cloudless summer day. The Pitt Meadows landscape is able to retain much more of its energy because of a lower albedo (less reflection), the presence of more water and plants, and lower surface temperatures. The higher LE values are attributable to the moist environment of rye grass and irrigated mixed-orchard ground cover for the sample area, contributing to the more moderate sensible heat levels throughout the day. 11. Why is there a temperature lag between the highest Sun altitude and the warmest time of day? Relate your answer to insolation and temperature patterns during the day. Incoming energy arrives throughout the illuminated part of the day, beginning at sunrise, peaking at local noon, and ending at sunset. As long as the incoming energy exceeds the outgoing energy, temperature continues to increase during the day, not peaking until the incoming energy begins to diminish in the afternoon as the Sun loses altitude. The warmest time of day occurs not at the moment of maximum insolation but at that moment when a maximum of insolation is absorbed. Thus, this temperature lag places the warmest time of day three to four hours after solar noon as absorbed heat is supplied to the atmosphere from the ground. Then, as the insolation input decreases toward sunset, the amount of heat lost exceeds the input, and temperatures begin to drop until the surface has radiated away the maximum amount of energy, just at dawn. The annual pattern of insolation and temperature exhibits a similar lag. For the Northern Hemisphere, January is usually the coldest month, occurring after the winter solstice, the shortest day in December. Similarly, the warmest months of July and August occur after the summer solstice, the longest day in June. • Review the temperature concepts and temperature controls that produce global temperature patterns. 12. Explain the effect of altitude on air temperature. Why is air at higher altitudes lower in temperature? Why does it feel cooler standing in shadows at higher altitudes than at lower altitudes? Air temperatures in the troposphere decrease with increasing elevation above Earth's surface (recall that the normal lapse rate of temperature change with altitude is 6.4°C/1000 m or 3.5°F/1000 ft). Thus, worldwide, mountainous areas experience lower temperatures than do regions nearer sea level, even at similar latitudes. Temperatures may decrease noticeably in the shadows and shortly after sunset. Surfaces both heat rapidly and lose their heat rapidly at higher altitudes. This is a result of lower density air having a lower specific heat, because a given volume of air can hold less heat energy than a denser volume of air. 13. What noticeable effect does air density have on the absorption and radiation of energy? What role does altitude play in that process? The density of the atmosphere also diminishes with increasing altitude, as discussed in Chapter 2. As the atmosphere thins, its ability to absorb and radiate heat is reduced. The consequences are that average air temperatures at higher elevations are lower, nighttime cooling increases, and the temperature range between day and night and between areas of sunlight and shadow also increases. 14. How is it possible to grow moderate-climate-type crops such as wheat, barley, and potatoes at an elevation of 4103 m (13,460 ft) near La Paz, Bolivia, so near the equator? The combination of elevation and low-latitude location guarantees La Paz nearly constant daylength and moderate temperatures, averaging about 9°C (48°F) for every month. Such moderate temperature and moisture conditions lead to the formation of more fertile soils than those found in the warmer, wetter climate of Concepción. 15. Describe the effect of cloud cover with regard to Earth's temperature patterns —review cloud-albedo forcing and cloud-greenhouse forcing. Clouds are moderating influences on temperature, producing lower daily maximums and higher nighttime minimums. Acting as insulation, clouds hold heat energy below them at night, preventing more rapid radiative losses, whereas during the day, clouds reflect insolation as a result of their high albedo values. The moisture in clouds both absorbs and liberates large amounts of heat energy, yet another factor in moderating temperatures at the surface. • Interpret the pattern of Earth's temperatures for January and July and annual temperature ranges. 16. What is the thermal equator? Describe its location in January and in July. Explain why it shifts position annually. The thermal equator, a line connecting all points of highest mean temperature (black dashed line on the maps in Figure 3.24 and 3.26), in January trends southward into the interior of South America and Africa, indicating higher temperatures over landmasses. The thermal equator shifts northward in July with the high summer Sun and reaches the Persian Gulf-Pakistan-Iran area. (relate this to specific heat). 17. Observe trends in the pattern of isolines over North America and compare the January average temperature map with the July map. Why do the patterns shift locations? Isotherms over North America vary with seasonal shifts in the Sun’s declination and daylength. As the ITCZ shifts toward the Southern Hemisphere, North America receives less solar radiation, due to reduced daylength and a lower angle of incidence this time of year. This correlates to reduced temperatures experienced during January in North America. As the ITCZ shifts toward the Northern Hemisphere, North America receives more solar radiation, due to increased daylength and a greater angle of incidence. Temperatures in North America will be more extreme. Due to the specific heat properties of land, North America will experience greater temperature extremes, the continent will lose energy rapidly in January due to land's low heat capacity, and the continent will heat rapidly in July due to the low amount of energy that is required to heat land. 18. Describe and explain the extreme temperature range experienced in north-central Siberia between January and July. As you might expect, the largest temperature ranges occur in subpolar locations in North America and Asia, where average ranges of 64°C (115°F) are recorded. The Verkhoyansk region of Siberia is probably the greatest example of continentality on Earth. The coldest area on the map is in northeastern Siberia in Russia. The cold experienced there relates to consistent clear, dry air, small insolation input, and an inland location far from any moderating maritime effects. Verkhoyansk and Omakon, Siberia, Russia, each have experienced a minimum temperature of –68°C (–90°F) and a daily average of –50.5°C (–58.9°F) in January. Verkhoyansk experiences at least seven months of temperatures below freezing, including at least four months below –34°C (–30°F)! July temperatures in Verkhoyansk average more than 13°C (56°F), which represents a 63C° (113F°) seasonal variation between winter and summer averages. You probably have your own favorite sets of stations to portray continental and marine characteristics. I present San Francisco and Wichita, Vancouver and Winnipeg, and Trondheim and Verkhoyansk and have included three pairs of cities in the overhead transparency packet. In simplest terms, these demonstrate continentality of the interior stations and the greater moderation of temperature characteristics of the coastal stations. With a more sophisticated analysis, cities in the western Basin and Range Province such as Elko, Nevada, probably exhibit the least maritime influence in the United States measured by indicator formulas, (i.e., the greatest degree of continentality). 19. Where are the hottest places on Earth? Are they near the equator or elsewhere? Explain. Where is the coldest place on Earth? The hottest places on Earth occur in Northern Hemisphere deserts during July. These deserts are areas of clear and dry skies and strong surface heating, with virtually no surface water and few plants. Locations such as portions of the Sonoran Desert area of North America and the Sahara of Africa are prime examples. Africa has recorded shade temperatures in excess of 58°C (136°F), such as a record set on 13 September 1922 at Al-Aziziyah, Libya (32° 32' N; 112 m or 367 ft elevation). The highest maximum and annual average temperatures in North America occurred in Death Valley, California, where the Greenland Ranch Station (37° N; –54.3 m or –178 ft below sea level) reached 57°C (134°F) in 1913. July is a time of 24-hour-long nights in Antarctica. The lowest natural temperature reported on Earth occurred on 21 July 1983 at the Russian research base at Vostok, Antarctica (78°27 S, elevation 3420 m or 11,220 ft): a frigid –89.2°C (–128.56°F). For comparison, such a temperature is 11°C (19.8°F) colder than dry ice (solid carbon dioxide)! Many sources of climatic data are available, including those on the Internet and accessed through our Home Page. A few print sources are suggested below: The National Weather Service maintains the Climatology of the United States for each of the 50 states and World Weather Records, updated in 1979. Local weather service offices prepare reports for metropolitan areas. One example is Tony Martini's “Climate of Sacramento, California,” NOAA Technical Memorandum NWS WR-65 Sacramento: Weather Service Office, April 1990, 70 pp. Check to see if your local or state climatologist has prepared such a report. For Canada, contact the Atmospheric Environment Service, Climatic Normals publications. Landsberg, Helmut E., ed. World Survey of Climatology, 15 volumes published 1969–1984. New York: Elsevier, North Holland. Pearce, E.A. and C.G. Smith. The World Weather Guide. London: Hutchinson and Company, 1984. Riordan, Pauline and Paul G. Bourget. World Weather Extremes. Fort Belvoir, VA: U.S. Army Corp of Engineers, 1985, available from USGPO. Rudloff, Willy. World Climates. Stuttgart,Germany: Wissenschaftliche Verlagsgesellschaft, 1981. Ruffner, James A. and Frank E. Blair, eds. The Weather Almanac. New York: Avon Books, 1977. Wernstedt, Frederick L. World Climatic Data. Lemont, PA: Climatic Data Press, 1972. Willmott, Cort J., John R. Mather, and Clinton M. Rowe. Average Monthly and Annual Surface Air Temperature and Precipitation Data for the World. Part 1, “The Eastern Hemisphere,” and Part 2, “The Western Hemisphere.” Elmer, NJ: C. W. Thornthwaite Associates and the University of Delaware, 1981. For a complete survey of CD-ROM resources see: Clifford F. Mass, “The Application of Compact Discs (CD-ROM) in the Atmospheric Sciences and Related Fields: An Update,” Bulletin of the American Meteorological Society, 74 no. 10, October 1993: 1901–1908. The article reviews CD-ROM technology and has two appendices: “Currently Available CD-ROM Titles in the Atmospheric Sciences and Related Disciplines,” and “Contact Information for CD-ROM Vendors.” The article references several data sets for climatological information. • Contrast wind chill and heat index and determine human response to these apparent temperature effects. 20. What is the wind chill temperature on a day with an air temperature of –12°C (10°F) and a wind speed of 32 kmph (20 mph)? 32 kmph (20 mph) of wind with a temperature of -12°C (10°F) results in a wind chill reading of -23°C (-9°F). 21. On a day when temperature reaches 37.8°C (100°F), how does a relative humidity reading of 50% affect apparent temperature? 37.8°C (100°F), with a relative humidity reading of 50% results in a heat index of category II (very hot) and an apparent temperature of 49°C (120°F). 22. What is the basis for the urban heat-island concept? Describe the climatic effects attributable to urban as compared with nonurban environments. What did NASA determine from the UHIPP overflight of Sacramento (Figure 3.30)? The surface energy characteristics of urban areas possess unique properties similar to energy balance traits of desert locations. See the six items of analysis in the chapter and the contents of Figure 3.28, 3.29, and 3.30. 23. Have you experienced any condition graphed in Focus Study 3.2, Figures 3.2.1 or 3.2.2? Explain. Personal analysis and response. 24. Assess the potential for solar energy applications in our society. What are some negatives? What are some positives? Solar energy systems can generate heat energy of an appropriate scale for approximately half the present population in the United States (space heating and water heating). In marginal climates, solar-assisted water and space heating is feasible as a backup; even in New England and the Northern Plains, solar-efficient collection systems prove effective. Kramer Junction, California, about 140 miles northeast of Los Angeles, has the world's largest operating solar electric-generating facility. The facility converts 23% of the sunlight it receives into electricity during peak hours. Rooftop photovoltaic electrical generation is now cheaper than power line construction to rural sites. Obvious drawbacks of both solar-heating and solar electric systems are periods of cloudiness and night, which inhibit operation. The success of solar energy appears tied to the political arena, for without tax incentives and formal encouragement, in amounts at least equal to those given the fossil-fuel industry, it is difficult to operate such a plant. I recommend that you write to the nonprofit organization listed below for their literature and designs. We purchased a simple box-cooker kit and find that it does extremely well for something made out of cardboard, one pane of glass, foil, and a reflector lid. The insulation in the walls is provided by crumpled newspaper and all the other materials are from recycled sources. You need about 15 minutes of direct sunlight per hour to cook food. We have cooked everything from pasta to bread to a whole turkey during the seven month period (April to October) at 40° N latitude. The only problem we have had was during the solar eclipse on July 11, 1991. With 59% of the Sun blocked by the Moon in Sacramento, California, temperature in the solar cooker dropped by 25°C (45°F). For a copy of “Your Own Solar Box—How to Make and Use,” “Teachers Guide Fun with the Sun,” and “Leaders Guide, Spreading Solar Cooking,” (all three for $12.) contact the following nonprofit group: Solar Cookers International (SCI), 1724 11th Street, Sacramento, California 95814; 916-444-6616; FAX-916-444-5379. The World Conference on Solar Cooker Use and Technology is held each year. A major effort is underway to place solar box cookers throughout the Third World. SCI also has videotapes, other teaching tools, and a newsletter dealing with solar cooking. Donations are tax deductible. Relative to solar energy and the focus study with this chapter, there are some key generalizations that help organize energy resources for analysis. A first step is to analyze the actual end-use energy demand in the United States, or any country. The pattern of consumer demand most accurately dictates what methods and modes should be selected to supply and meet that energy need. Presently in the United States, 58% of end-use energy need is for heat roughly split one-half above and one-half below the boiling temperature of water. Another 38% is for mechanical motion, including 4% for electric motors. And finally, 4% is classified as necessary electrical. If the taxpayer is worried about taxes and big government, and is basically conservative, then having such a localized consumer-driven energy plan would seem wisest and most conservative of capital, political power, and economic control. Secondly, let's briefly examine two categories of energy resources and their characteristics. The essays in the text on wind and solar resources should be viewed in the context of these two sets of energy characteristics. These two paradigms can form the basis of a class discussion if there is time. Energy Resource Characteristics Centralized energy Decentralized energy Nonrenewable sources Renewable sources Indirect to the consumer Direct to the consumer Capital intensive Labor intensive Limited domestic supply Unlimited domestic supply Large foreign imports No foreign imports Monopolies/cartels Widely available “Big” government control Home and neighborhood control Concentrated tax Diffused tax advantages advantages Overhead Transparencies for Chapter 3 Chapter 3 Atmospheric Energy and Global Temperatures 42. 3.1 Energy gained and lost by Earth’s surface and atmosphere 43. 3.2 Insolation at Earth’s surface 44. 3.4 Sun refraction photo and art 45. 3.5 Albedo values for various surfaces 46. 3.6 a, b; 3.8 a and b Effects of clouds SW and LW (top); energy effects of two cloud types (bottom) 47. 3.8c and CO3 Jet contrails (top); cloud development from contrail 48. 3.7 Heat energy transfer process 49. 3.9 a, b CERES shortwave (top) and longwave (bottom) global maps 50. 3.10 Detail of Earth-atmosphere energy balance 51. 3.11 Energy budget by latitude 52. 3.12 Daily radiation curves 53. 3.13 Surface energy budget 54. 3.15 Temperature scales (K, °C, °F) 55. 3.17 Temperature pattern variation by latitude 56. 3.18 Effects of altitude and latitude (La Paz and Concepción, Bolivia) 57. 3.20 Land-water heating differences 58. 3.22 a, b, scale Sea-surface temperatures Feb. 1999 (top); SSTs July 1999 (bottom) 59. 3.23 Comparison: San Francisco and Wichita 60. 3.24 a,b,c Global temperatures for January 61. 3.25 Comparison: Trondheim and Verkhoyansk 62. 3.26 Global temperatures for July 63. 3.28 Global annual temperature ranges 64. 3.29 and 3.30a Urban environment (top); Typical urban heat island profile (bottom) 65. H.L.C. 3.1.1 Loss of Arctic Ocean ice pack 1979, 2003 66. F.S. 3.2.1 and 3.2.2 Wind-chill temperature index (top); Heat index (bottom) 50 • Atmospheric Energy and Global Temperatures Atmospheric Energy and Global Temperatures • 50 • Atmospheric Energy and Global Temperatures Atmospheric Energy and Global Temperatures • 50 • Atmospheric Energy and Global Temperatures Atmospheric Energy and Global Temperatures • 50 • Atmospheric Energy and Global Temperatures Atmospheric Energy and Global Temperatures •