Chapter 10.1 – Global Systems and Solar Energy

1. Chapter 10.1 – Global Systems and Solar Energy (pages 364 – 374 in your text)

2. Systems • A system is the object or the group of objects that scientists wish to study. Systems have a boundary; everything other than the system is called the surroundings. Researchers can learn a lot about a particular system by observing what enters and leaves it. • Systems are classified according to the interactions of a particular system with its surroundings.

3. Open system • Open system: allows energy and matter to cross the system’s boundary. • example – an aspen tree; gases are exchanged and solar energy enters the tree.

4. Closed System • Closed system: allows only energy but not matter to cross the system’s boundary. • example – the Earth; solar energy enters the atmosphere, radiant energy is given off.

5. Isolated system • Isolated system: neither matter nor energy cross the boundary. • example – the Universe is the only true isolated system.

6. Earth as a system • The boundary of the system we call Earth is the atmosphere. Solar energy enters the atmosphere; some energy is reflected and some energy is absorbed. • Some of the energy absorbed by the atmosphere is absorbed by the surface of the Earth, some is reflected away. • All of the energy that is absorbed by the atmosphere and by the surface of the Earth is eventually radiated back into space.

7. Earth’s biosphere • Earth’s biosphere is a global system. When radiant energy from the Sun reaches Earth it interacts with a thin layer of air, land and water. This layer is called the biosphere because all life on Earth exists within this thin layer. The following terms are used when discussing the air, land and water: atmosphere, lithosphere, hydrosphere.

8. atmosphere • Atmosphere (air) is a mixture of nitrogen and oxygen and other gases that extend 800 km above Earth’s surface. Most of the atmosphere is concentrated in the lower two layers – the troposphere (0 – 12 km) and the stratosphere (13 – 50 km).

9. lithosphere • Lithosphere (land) is Earth’s crust that forms land (continental crust) above sea level and at the ocean bottom (oceanic crust), as well as the upper part of Earth’s mantle. The lithosphere varies in thickness from 100 – 200 km.

10. hydrosphere • Hydrosphere (water) is water on or near Earth’s surface; includes water in oceans, rivers, lakes, streams, underground reservoirs, and in the atmosphere. Earth’s surface is 70% water and 30% land; the hydrosphere plays an important role in the absorption of sunlight and the distribution of thermal energy. Clouds (water droplets found in the troposphere) reflect much of the incoming solar radiation. The cryosphere consists of water that is temporarily frozen in polar ice caps, snow, permafrost, and glaciers.

11. hydrosphere

12. Answer the Questions • 1. Two gases that make up 99% of Earth’s atmosphere are • A. carbon dioxide and oxygen • B. sulfur dioxide and nitrogen dioxide • C. oxygen and nitrogen • D. argon and methane

13. 2. Passenger airplanes cruise at an altitude of 11 000 m on long flights. In which layer of the atmosphere do these airplanes cruise? • A. mesosphere • B. stratosphere • C. thermosphere • D. troposphere

14. 3. Which layer of the atmosphere contains most of the carbon dioxide and water vapour in the atmosphere? • A. mesosphere • B. stratosphere • C. thermosphere • D. troposphere

15. 4. What are the three interacting components of the biosphere? • atmosphere (air), lithosphere (land), hydrosphere (water).

16. Earth’s radiation budget • The conditions in the biosphere remain uniquely suited for life. Constant flow of radiant energy into and out of the biosphere allows for the Earth’s temperature to remain fairly constant.

17. Earth’s radiation budget • Radiation is the mechanism of energy transfer in which atoms or molecules emit electromagnetic waves. These waves carry the energy through space and release the energy only when they interact with some form of matter. Radiation is the process by which solar energy reaches Earth.

18. Electromagnetic radiation

19. Earth’s radiation budget • Earth maintains an energy balance and a temperature balance by radiating as much energy into space as it absorbs from the Sun. This balance is known as the radiation budget. Radiation Budget = Total incoming energy – Total outgoing energy

20. Earth’s radiation budget

21. albedo • The colour of a surface affects the amount of energy it will absorb or reflect. Dark surfaces absorb energy and light surfaces reflect energy. The reflectivity of a surface is known as its albedo. For example, a snow-covered field has a high albedo; it reflects 70-80% of the energy striking it. In the summer the same field growing crops will have a lower albedo; it will only reflect 20% or less of the incoming energy.

22. albedo

23. The greenhouse effect • Greenhouse gases, such as water vapour, carbon dioxide, methane, nitrous oxide, ground level ozone, CFCs, and HFCs absorb infrared radiation in all directions, including back to Earth’s surface. The radiation warms the surface of the Earth and the atmosphere before it is lost to space. • The retention of heat by greenhouse gases is known as the greenhouse effect.

24. The greenhouse effect

25. ANSWER THE QUESTIONS • 5. List the following forms of radiant energy from longest to shortest wavelengths, number the blanks 1-6. ___visible light ___ ultraviolet ___ radio waves ___ microwaves ___ infrared light ___ cosmic rays

26. 6. Radiant energy can be reflected or absorbed by a substance. Which causes a rise in temperature — reflection or absorption? • 7. What is the percent of solar radiation reflected by a surface called?

27. 8.Use the picture at the top of the page 4 to answer the questions that follow: a. What percent of the incident solar energy is reflected? b. What percent of the incident solar energy is actually incoming energy for Earth’s net radiation budget? c. What percent of the incident solar energy is re-emitted to space by clouds and the atmosphere? d. What percent is re-emitted directly from Earth’s surface to space?

28. Complete the pie graph below to show what happens to the incident solar energy on Earth. Show the percent of incident solar energy reflected into space, the percent absorbed by clouds and the atmosphere, and the percent absorbed by land and oceans.

30. Climates and seasons • Average temperatures may fluctuate a great deal from summer to winter months. The average temperatures are quite different in various parts of the world. These characteristics are part of what we call climate. • Climate is the trend in temperature, atmospheric pressure, humidity, and precipitation over a period of time of many years. • Weather refers to these conditions as they are at one place and time.

31. Earth’s tilted axis • The 24 h rotation of the Earth on its axis results is warming during the day and cooling during the night. The tilt of the Earth is called the angle of inclination. • The angle of inclination is the angle of the equator with respect to the plane of Earth’s orbit around the Sun.

32. The north and south poles are tiled towards the Sun for approx. half the year. • When the pole is tilted towards the Sun it is summer; tilted away it is winter. • The seasons in the two hemispheres are opposite; when it is summer in the Northern Hemisphere it is winter in the Southern Hemisphere.

33. Summer is slightly longer in the Northern Hemisphere because of Earth’s slightly elliptical orbit around the Sun. If the Earth did not have a tilted axis of rotation we would not observe seasons.

34. Climate zones • The polar zones have 24 h of darkness during parts of the winter and 24 h of sunlight during parts of the summer. • The Sun’s rays are never perpendicular to Earth’s surface in the temperate zones; temperature and weather conditions are quite variable. • The Sun’s rays are perpendicular to Earth’s surface at some locations in the tropical zone throughout the entire year; average temperatures in these areas are warmer than those in other areas.

35. Answer this question