What Causes Climate?

1. What Causes Climate? Chapter 9

2. Upside Down Climate • The climate conditions are reversed below the Equator in the Southern Hemisphere • Winter in Canada is Summer in Australia or anywhere in the Southern Hemisphere • In the same way Winter in Australia is Summer in Canada

3. The Reason for Season Reversal • When you look at a globe, you will see it tilts. • This represents the Earths tilt at 23.5 º • While the Earth orbits the sun it is always tilted in the same angle. • As a result, The Northern and Southern Hemispheres receive direct overhead rays at different time of the year.

4. Comparing Global Climates • (cf. Chapter 6) “Climate describes weather conditions that occur in a specific area over a long period of time • A climate graph shows temperature and precipitation information for a particular place • Temperature is represented in red • Precipitation in blue

5. The Effects of The Sun • Temperatures are different around the world because some locations receive more heat and light from the sun than others • Solar radiation, the sun’s rays, creates different climates in different parts of the Earth • Near the Equator, the rays strike directly making it intense • Further away from the Equator, the rays are spread out and cover large areas due to the curvature of the Earth’s surface

6. The Sun and Temperature • Temperatures are different around the world because there is more heat and light in some places • Solar radiation, the sun’s rays, create different climates in different parts of the Earth. • Near the Equator the suns rays hit directly and they are more powerful because they have less distance to travel due to the curve of the Earth.

7. The Sun and Precipitation • High temperatures and heavy precipitation often occur together • This is because of the water cycle – higher temperature cause more evaporation, which leads to condensation and precipitation • Clouds build up quickly (by late afternoon) and the moisture is released in a short heavy rainfall. • This type of rainfall is called convectional precipitation.

8. Altitude • High altitude affects precipitation • Wet regions are located beside oceans • Moist winds come ashore and encounter mountain chains • As air rises over mountains, it cools and condenses into clouds. The clouds then release the droplets and the water flows down the side of the mountain. • This is called orographic precipitation.

9. Winds And Air Masses • Winds blow out of air masses. • In January Canada is affected by a regular flow of air from the North (cold temperatures). • Changes in July as the sun warms the Northern Hemisphere that Canada receives warm air from the South • Air masses originate over ocean or land areas in warm or cold latitudes • As they move, they bring moisture and temperature conditions with them

10. Other Currents and Bodies of Water • Ocean Currents and the proximity of bodies of water also affect climate • Water absorbs heat to a greater depth than land. • Winter temperatures are milder in coastal areas when this stored heat is released • Summer temperatures are cooler when the heat is absorbed by the bodies of water