1. Warm Up 3/7/08
Earth receives energy from the sun through what method of heat transfer?
a. radiation c. convection
b. conduction d. none of the above
Which process involves mass movement within a substance?
a. radiation c. conduction
b. convection d. reflection
All matter is composed of atoms or molecules that have energy of motion, also known as ____.
a. solar energy c. potential energy
b. radiation d. kinetic energy
Answers: 1) a. 2) b. 3) d.

2. Temperature Controls
Chapter 17, Section 3

3. Why Temperatures Vary
A temperature control is any factor that causes temperature to vary from place to place and from time to time
Because variations in the angle of the sun’s rays and length of daylight depend on latitude, they are responsible for warmer temperatures in the tropics and colder temperatures toward the poles
Factors other than latitude that exert a strong influence on temperature include heating of land and water, altitude, geographic position, cloud cover, and ocean currents

4. Concept Check List three factors that influence temperature.
Latitude, differential heating of land and water, altitude, geographic position, cloud cover, ocean currents

5. Land and Water
Land heats more rapidly and to higher temperatures than water
Land also cools more rapidly and to lower temperatures than water
Temperature variations, therefore, are considerably greater over land than over water
The Southern Hemisphere shows smaller annual temperature variations, due to it having more water than the Northern Hemisphere

6. Mean Monthly Temperatures for Vancouver and Winnipeg

7. Variation in Annual Mean Temperature Range with Latitude

8. Geographic Position
A coastal location where prevailing winds blow from the ocean onto the shore (a windward coast) experiences considerably different temperatures than does a coastal location where the prevailing winds blow from the land to the ocean (a leeward coast)
The windward coast will experience all of the moderating effects of the ocean, cool summers and mild winters
The leeward coast will have a more continental pattern because winds do not carry the ocean’s influence to shore
Mountains may act as a barrier for a windward coast, and the opposite side will not receive the moderating effect of the ocean

9. Monthly Temperatures for Eureka, CA and New York City

10. Monthly Temperatures for Seattle and Spokane, WA

11. Altitude, Cloud Cover and Albedo
Two cities at the same latitude may have much different temperatures due to altitude, with the higher city’s temperature being colder
Albedo – the fraction of total radiation that is reflected by any surface
Many clouds have a high albedo, and therefore reflect a significant portion of the sunlight that strikes them back to space
During the day, clouds will keep the temperatures cooler by not allowing as much solar energy to get through
During the night, clouds act as a blanket by absorbing outgoing radiation and reradiating it back to the surface
The effect of cloud cover is to reduce the daily temperature range

12. Monthly Temperatures for Quito and Guayaquil, Ecuador

14. Clouds Reduce Daily Temperature Range

15. Concept Check
Why do many clouds reflect a significant amount of sunlight back to space?
Clouds reflect a significant amount of sunlight back to space because of their high albedos.

16. World Distribution of Temperature
Isotherms – lines that connect points that have the same temperature
The isotherms on a world isothermal map generally trend east and west and show a decrease in temperatures from the tropics toward the poles

17. World Distribution of Mean Temperature for January

18. World Distribution of Mean Temperature for July

19. Assignment Read Chapter 17 (pg. 476-493)
Do Chapter 17 Assessment #1-30 (pg )
STUDY for Chapter 17 Quiz!

20. Cool Down How do the heating of land and water differ?
Land heats and cools more rapidly and to greater temperature extremes than water does.
Why do some coastal cities experience a moderation of temperature from water, while other do not?
Some coastal cities are influenced more strongly from prevailing ocean winds than others are.
What is one new thing you learned today? Explain.