HOW CAN ENERGY BE TRANSFERRED?

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# HOW CAN ENERGY BE TRANSFERRED?

## HOW CAN ENERGY BE TRANSFERRED?

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##### Presentation Transcript

1. 1. CONDUCTION: HOW CAN ENERGY BE TRANSFERRED? 2. CONVECTION: 3. ADVECTION: 4. RADIATION:

2. CONDUCTION

3. CONVECTION

5. RADIATION - - + - -

6. Before you leave this section • 1. Be able to list the 4 means of energy transfer, and identify the one which transfers all energy into and out of the Earth’s climate system. • 2. Be able to describe the means by which energy is transferred in each. • 3. Be able to reproduce, with explanation, four concept sketches of the energy transfer mechanisms.

7. What controls the quantity and type of energy the Earth System receives? • How much? • What type?

8. STEFAN-BOLZMAN • E= • T = • d =

9. WEIN • Wmax= • T =

10. SUN AND EARTH Surface Energy Wmax Temp (Wm-2) (μ) Sun Earth

11. Before you leave this section • 1. Name the laws and understand the physical concepts behind the control that the surface temperature of an object exerts on the quantity and dominant wavelength of Electromagnetic Radiation that it emits. • 2. Understand why these two properties of Electromagnetic Radiation are related in the opposite fashion to the temperature of the object. • 3. Be aware of what the term “temperature” of an object actually means in terms of energy and the various scales that we use to measure it.

12. PLANCK’S LAW Sun

13. Sun and Earth

15. Before you leave this section • 1. Graph the types and quantities of radiation being emitted by the Sun and Earth. • 2. Know the relative ordering of the various components of the Electro-magnetic Radiation spectrum based on wavelength, including the colors of the visible portions of that spectrum.

16. SOLAR CONSTANT

17. Before you leave this section • 1. Be able to describe conceptually the derivation of the Solar Constant. • 2. Know the numerical value of the Solar Constant and be able to provide a verbal definition. • 3. Explain why the Solar Constant may not actually be a true “constant”, but vary periodically with a frequency of about 11 years

18. WHAT IS THE ZENITH ANGLE AND WHY SHOULD WE CARE?

19. Before you leave this section • 1. Be able to define the zenith angle. • 2. Know what the zenith angle will be at sunrise and sunset and when it will at its minimum. • 3. Explain how the zenith angle controls the proportion of the Solar Constant falling on a unit area (square meter) of the Earth’s surface.

20. Why are some places hot and others cold? Why are some times of the year warmer than others? A. SPATIAL B. TEMPORAL 1. Annual 2. Seasonal 3. Daily

21. CAN WE QUANTIFY THE EFFECT OF THE ZENITH ANGLE AND LATITUDE AT NOON? SUN N Equator Center of Earth S

22. CAN WE QUANTIFY THE EFFECT OF THE ZENITH ANGLE AND LATITUDE AT NOON? SUN N Equator Center of Earth S

23. CAN WE QUANTIFY THE EFFECT OF THE ZENITH ANGLE AND LATITUDE AT NOON? SUN N Equator Center of Earth S

24. CAN WE QUANTIFY THE EFFECT OF THE ZENITH ANGLE AND LATITUDE AT NOON? SUN N Equator Center of Earth S

25. Before you leave this section • 1. Be able to sketch the relationship between the latitude of a locations and the zenith angle at noon on March and September 21. • 2. Be able to explain why the outside of the Earth’s atmosphere at various latitudes will receive varying portions of the solar constant at noon on these days. • 3. Understand the trigonometric way in which the zenith angle controls the proportion of the solar constant intercepted. • 4. Understand this trigonometric function sufficiently well to be able to explain why large/small zenith angles are associated with varying proportions of the solar constant.

26. HOW DOES THE EARTH’S ORBIT AROUND THE SUN AFFECT INSOLATION? BYLTS

27. Before you leave this section • 1. Be able to identify the dates of the Aphelion and Perihelion. • 2. Know approximate Earth-Sun distances at these times, and the average Earth-Sun distance. • 3. Understand how to make the appropriate adjustment to the value of the solar constant based upon actual Earth-Sun distance, and be aware of the potential magnitude of this impact.

28. June 21 N Sun on horizon z = 90° S U N S Cancer Equator U Sun overhead z = 0° N Antarctic s Sun on horizon z = 90°

29. WHERE IS THE SUN OVERHEAD AT NOON? December 22 N Sun on horizon z = 90° S U N S Arctic Z = >0° = 0 + 23.5 = 23.5° U Sun overhead z = 0° Equator Capricorn N 23.5°S Sun on horizon z = 90° s

30. BOTTOM LINE March and September: Summer (Jun. in N, Dec. in S): Winter (Dec. in N, Jun. in S):

31. Before you leave this section • 1. Given the latitude of a location and the time of the year, be able to estimate the zenith angle at noon. • 2. Know at which latitude the sun will be directly overhead at the varying times of year. • 3. Know the latitudes beyond which the sun is never directly overhead. • 4. Know the latitudes beyond which there is at least one day of total darkness (and one of light) and the seasons in which these occur.

32. Why do the lengths of Day and Night vary with the seasons? September 21 SUN June 21 December21 March 21

33. N N N Arctic C. Cancer Equator Capricorn Antarctic C. s s s

34. THE BOTTOM LINE 1. 2. 3. 4.

35. Before you leave this section • 1. Be able to sketch the orientation of the Earth’s axis of rotation with respect to the Sun during the course of the Earth’s annual revolution around the Sun, and identify the Circle of Illumination. • 2. Given key times of year and/or key geographic latitudes be able to estimate the length of daylight. • 3. Understand the 4 “bottom line” items with regard to controls on the seasonal and spatial variations in the length of daylight.

36. SEASONAL CHANGES IN INSOLATION WITH LATITUDE

37. GEOGRAPHY MATTERS!

38. Seasonal Changes in Daily Insolation 0° 10°N 30°N 50°N 70°N 90°N

39. PUTTING IT ALL TOGETHER