Factors that Affect Climate

1. Factors that Affect Climate

2. Deep space is very cold. The temperature in deep space is – 272°C. • Earth is much warmer than that! So where does the heat come from? • The Sun!

3. Effect of Distance from the Sun • Mercury is 1/3 as far from the sun as Earth • The mean daytime temperature on Mercury is +350°C.

4. Effect of Distance from the Sun • Pluto is 40 times as far from the sun as Earth. • The mean daytime temperature on Pluto is -230°C.

5. Does Earth’s Distance from the sun vary? • Yes, the orbit varies from circular to elliptical. • An elliptical orbit means that the sun is closer at some seasons that at others. • This is referred to as eccentricity.

6. Is the Earth tilted on its axis? • Yes! • Evidence? • The Seasons • The NorthernHemisphere gets more solar energy in the summer and therefore it is warmer then.

7. Is this tilt constant? • No. • The tilt varies from 22.0° to 24.5°. • This change in tilt affects the energy arriving at different parts of the Earth.

8. Does the location on a sphere affect how much solar radiation arrives at that place? • Yes. • The closer to the Equator, the more days the sun is directly overhead.

9. But that energy is distributed over a larger areaas we move away from the Equator The sameamount of light energy comes from the sun The result is that polar areas are coolerthan Equatorial areas

10. Does the atmosphere affect Climate? How can we tell? • The Earth and the Moon get the same amount of energy from the Sun and yet… • Moon Temperatures • Day  +100°C • Night  -150°C • Earth Temperatures • Day  +22°C • Night  +14°C

11. So clearly the atmosphere has two effects • It keeps the Earth cooler during the day • It keeps the Earth warmer at night

12. How does the atmosphere keep the Earth cooler during the day? • The atmosphere acts as an umbrellato keep some of the sun’s rays from reaching the Earth

13. B E A C D F

14. How does it keep the Earth warmer at night? • The atmosphere acts like a blanket to keep heat in.

15. Does the atmosphere affect other aspects of climate? • Winds! What causes wind to blow? Air now cools away from warm ground Warm, less dense air is pushed up Cool, more dense air falls Sun’s rays warm the ground warm Surface winds move energy around the planet

16. How else do winds affect climate? • Winds push ocean currentsthat also move energy around the Earth

17. Volcanoes and Climate • Volcanic ash rises high into the atmosphere as it is hot • It blocks the sunlight from reaching the Earth and so causes coolingof the climate • It may also act as a nucleus for cloud formation and increase rainfall

18. 2 1 3 Question! • Places #1, #2 and #3 are all at the same latitude. • Yet they do not experience the same climate? Why?

19. Activity: Comparing heat Absorption of Water and Soil • get a beaker with 100mL of room temperature water • get a beaker with 100mL of room temperature soil • place a thermometer in each beaker • place a lamp close to both beakers & switch it on • take a reading from both thermometers every minute for 7 minutes • switch off lamp and continue recording temperature every minute for 5 minutes

20. Results • Which one warmed up faster? • Which one cools down faster?

21. Hydrosphere and Climate • Water has a higher specific heat capacity than land. So? • Therefore it takes longer to warm upa lake or an ocean than it does a field or a continent. • Similarly, an ocean or a lake takes longer to cool down.

22. 2 1 3 • Which place will be fastest to warm-up in the Spring? Why? • #2 is far from any water and land warms quickly.

23. 2 1 3 • Which place will be slowest to cool down in the fall? • #1 as it is by a large ocean.

24. 2 1 3 • Which place will have the most moderate climate? • #1 • Which place will have the most extreme climate? • #2 • Which place will be most like Oakville? • #3

25. Albedo and Climate • Albedo  Relative amount of the Sun’s energy reflected • What types of surface reflect sunlight? • Water? No! • Land? No! • Snow? Yes!

26. Demonstrating Albedo Effects • We have just done a lab to demonstrate the relative heat capacity of water and soil. • Now we will use white sugar and brown sugar to demonstrate the influence of albedo on temperature. • “Create a hypothesis that relates the albedo of white and brown sugar to the change in temperature above and below the surface of sugar samples.” • Plan how you will do this demonstration and then show you plan to the teacher. • Conduct the experiment for 5 – 10 minutes based on time available.

27. Albedo and ClimateEffects of Albedo on the Arctic • white snow reflects lots of light and heat • ice is darker and so reflects less heat and so starts to melt • water is much darker and absorbs much more heat and start to warm

28. Effects of changing vegetation on Albedo • cutting down a forest and planting crops cools the Earth • cutting down trees and paving the field warms the Earth • cutting down a forest and concreting the area cools the Earth!

29. Positive Feedback Loop • A positive feedback loop increases the effect of the interacting parts • Albedo Warming: albedo decreases as ice become water darker water absorbs more heat ice melts Arctic gets warmer

30. During Ice Ages we see the opposite • Albedo Cooling albedo increases as water become ice lighter ice absorbs less heat ice forms Arctic gets cooler

31. Negative Feedback Loops and Climate Change • A negative feedback loop decreases the effect of the interacting parts clouds increase clouds shade the ground evaporation increases ground cools sun warms the ground clouds dissipate evaporation decreases

32. Can you think of any other examples of positive or negative feedback loops affecting local climate? • a cold, wintery day at the cottage • you burn wood to stay warm • ash from the wood dirties the snow and lowers albedo • dirty snow now absorbs more heat so area warms • feeling warmer, you burn less wood • the new snow is cleaner and so reflects more heat • you now have another cold, wintery day at the cottage • Is this positive or negative? • Negative