1. Science ~ chapter 9 climate
Miss Nelson

2. Section 1
What Causes Climate?

3. Anticipatory set
Differences in pressure, heat, air movement, and humidity result in changes of weather.

4. standards
S 6.4.a – Students know the sun is the major source of energy for phenomena on Earth’s surface; it powers winds, ocean currents, and the water cycle S 6.4.e – Students know differences in pressure, heat, air movement, and humidity result in change in weather

5. The big idea The main factors that influence temperature are: Latitude
Altitude
Distance from larger bodies of water
Ocean currents

6. Key terms
Climate – the average long-term conditions of temperature, precipitations, winds, and clouds in an area
Microclimate – climate conditions within a small area that differ from those in the surrounding area
Marine climate – the climate of some coastal regions, with relatively warm winters and cool summers
Continental climate – the climate of the centers of continents, with cold winters and warm or hot summers

7. Key terms
Ocean current – a large stream of moving water that flows through the ocean in a regular pattern
Windward – the side of a mountain range that faces the oncoming wind
Leeward – he side of a mountain range that faces away from the oncoming wind
Monsoon – sea or land breeze over a large region that changes direction with the seasons

8. Scientists use two main factors to determine climate:
What causes climate?
Scientists use two main factors to determine climate:
Precipitation
temperature

9. Factors affecting temperature
Main factors that influence temperature are:
Latitude
Altitude
Distance from large bodies of water
Ocean currents

10. latitude
Review World Temperature Zones for the effects of latitude on temperature

11. altitude
In the case of high mountains, altitude is a more important climate factor than latitude
As a result, highland areas everywhere have cool climates, no matter what their latitude

12. Distance from large bodies of water
Oceans or large lakes can affect temperature
Oceans make the temperatures of nearby land less extreme (than they would be without the ocean)
Water heats up more slowly than land
Water cools down more slowly than land
Winds off the ocean often prevent extremes of hot and cold in coastal regions

13. Ocean currents Marine climate are often influenced by ocean currents
Some warm surface currents move heat from the tropics toward the poles
Affects climate as the warm ocean water warms the air above it
The best warm water current is the Gulf Stream
View the Gulf Stream currents on page 349 of your textbook

14. Factors affecting temperature
Read Factors Affecting Temperature on pages 347 – 349 of your textbook

15. Factors affecting precipitation
The main factors that affect precipitation are:
Prevailing winds
The presence of mountains
Seasonal winds

16. Weather patterns depend on the movement of huge air masses
Prevailing winds
Weather patterns depend on the movement of huge air masses
These air masses are move from place to place by prevailing winds
The directional winds that usually blow in a region

17. Prevailing winds Air masses can be warm or cool, dry or humid
The amount of water vapor in the air mass influences how much rain or snow will fall
The amount of water vapor in the prevailing wind also depends on where the winds come from
Winds that blow inland from oceans or large lakes carry more water vapor than winds that blow from over land

18. Mountain ranges
A mountain range in the path of prevailing winds can also influence where precipitation falls
When humid winds blow from the ocean to the coastal mountains, they are forced to rise
As they rise the air cools and its vapor condenses, forming clouds

19. View Figure 4 on pages 350 – 351 of your textbook
Mountain ranges
The Sierra Nevada mountains have a major effect on California’s climate
Extremely dry areas (such as Death Valley) are located on the leeward side of the mountains
View Figure 4 on pages 350 – 351 of your textbook

20. Seasonal winds
A seasonal change in wind patterns can affect precipitation
Sea and land breezes over a large region that change direction with the seasons are called monsoons
Thailand and parts of India receive much of their rain from the summer monsoons
Monsoon winds also bring rain to coast areas in West Africa and northeastern South America

21. Regions affected by monsoons receive very little rain in winter
Seasonal winds
Regions affected by monsoons receive very little rain in winter
In the winter, the land cools and becomes colder than the ocean
A “land breeze” blows from the land to the ocean, which carries little moisture

22. Seasonal winds
The Santa Ana winds are hot, dry winds that often blow in Southern California during fall and early winter
Cool air from the desert blows toward the coast
As air flows down the mountain, it is compressed and warms up
The humidity of the air drops and vegetation dries out, creating a potential fire hazard

23. Factors affecting precipitation
Read Factors Affecting Precipitation on pages 350 – 351 of your textbook

24. The seasons
The seasons are caused by the tilt of Earth’s axis as Earth travels around the sun

25. View Figure 7 on page 353 of your textbook
Tilted axis
The axis is an imaginary line through Earth’s center that passes through both poles
The axis ALWAYS points in the same direction
The north end of the axis is pointed away from the sun for part of the year, and toward the sun for another part of the year
View Figure 7 on page 353 of your textbook

26. Effect of the tilted axis
In June the northern hemisphere receives radiation (heat) from the sun at a more direct angle
In December, the north end of Earth’s axis is tiled away from the sun

27. Read The Seasons on page 352 of your textbook

28. Check for understanding
Define climate. What are the factors that affect temperature?

29. Check for understanding
Define climate. Cimate refers to the long-term, average conditions of temperature, precipitation, winds, and clouds in an area. What are the factors that affect temperature? The facts that affect temperature are latitude, altitude, distance from large bodies of water, and ocean currents.

30. Modeling / guided / independent
Complete the Modeling, Guided Practice, and Independent Practice Sections of your Climate 9-1 Worksheet.