1. Do Now: Analyze the following images
Do Now: Analyze the following images. Why is one of the earth’s land surface a desert, another a grassland, and another a forest?

2. Aim: What factors influence climate?
Memory Check: What is the difference between weather and climate?
Flash Card

3. Generalized Map of the Earth’s Current Climate Zones
Generalized Map of the Earth’s Current Climate Zones. What is the general type of climate in NY?
Figure 7.2: Natural capital.
This generalized map of the earth’s current climate zones shows the major ocean currents and upwelling areas (where currents bring nutrients from the ocean bottom to the surface). See an animation based on this figure at CengageNOW. Question: Based on this map, what is the general type of climate where you live?
Fig. 7-2, p. 149

4. Climates vary due to: Air circulation in lower atmosphere due to:
Uneven heating of the earth’s surface by sun
Rotation of the earth on its axis
Properties of air, water, and land
Ocean currents
Prevailing winds
Earth’s rotation
Redistribution of heat from the sun
Surface currents and deep currents

5. Global Air Circulation
Figure 7.3: Global air circulation: The largest input of solar energy occurs at the equator. As this air is heated, it would naturally rise and move toward the poles (left). However, the earth’s rotation deflects this movement of the air over different parts of the earth. This creates global patterns of prevailing winds that help to distribute heat and moisture in the atmosphere and result in the earth’s variety of forests, grasslands, and deserts (right).
Fig. 7-3, p. 149

6. Coriolis Effect
A wind deflection pattern first identified by Gaspard-Gustave de Coriolis ( ) in 1835
Northern Hemisphere winds deflect to the right (clockwise)
Southern Hemisphere winds deflect to the left (counterclockwise)

7. Convection Currents Solar Energy warms Earth’s surface
Radiation heating transfers heat to the atmosphere
Warmed gases expand, become less dense, & rise
Creates a vertical column called a Convection Current

8. Surface winds
Warm air currents can hold a lot of moisture (water vapor) compared to the surrounding air
Why can warm air hold more water vapor?
When the warm air rises, cooler air flows along Earth’s surface in the warm air’s place
helps distribute heat and moisture in the atmosphere.

9. Sea v. Land Breezes

10. How do you think this loop affects climates of the coastal areas around it?
Figure 7.5: Connected deep and shallow ocean currents: A connected loop of shallow and deep ocean currents transports warm and cool water to various parts of the earth. This loop, which rises in some areas and falls in others, results when ocean water in the North Atlantic near Iceland is dense enough (because of its salt content and cold temperature) to sink to the ocean bottom, flow southward, and then move eastward to well up in the warmer Pacific. A shallower return current, aided by winds, then brings warmer, less salty, and thus less dense water to the Atlantic. This water then cools and sinks to begin this extremely slow cycle again. Question: How do you think this loop affects the climates of the coastal areas around it?
Fig. 7-5, p. 150

11. Homework: Re-read pages 152-166 Answer critical thinking 7-8 on pg 166
Factors Affecting Biome Distribution worksheet

12. Dew Point
Occurs when warm moist air rises into the cooler atmosphere & cools to the temperature that water vapor condenses into liquid water
Creates clouds

13. Global Air Circulation
Figure 7.3: Global air circulation: The largest input of solar energy occurs at the equator. As this air is heated, it would naturally rise and move toward the poles (left). However, the earth’s rotation deflects this movement of the air over different parts of the earth. This creates global patterns of prevailing winds that help to distribute heat and moisture in the atmosphere and result in the earth’s variety of forests, grasslands, and deserts (right).
Fig. 7-3, p. 149

14. Precipitation
When condensation continues, drops get bigger in clouds & are too large to be held up by gravity
They fall as precipitation, which can be frozen or liquid

15. Convection Cells
Heat and moisture are distributed over the earth’s surface via six giant convection cells at different latitudes.
2 Hadley Cells
2 Ferrel Cells
2 Polar Cells
The resulting uneven distribution of heat and moisture over the planet’s surface leads to the forests, grasslands, and deserts that make up the earth’s terrestrial biomes.

16. Winds Currents & Convection Cells Diagrams

17. Hadley Cells On a local level --> accounts for land & sea breezes
On a global scale --> cycle starts over equator, where warm moist air evaporates & rises into the atmosphere
Accounts for tropical rain equator line due to precipitation in that region
Then cool dry air descends 30 deg North & South of equator
Accounts for belts of deserts around Earth at that latitude

18. Global Air Circulation, Climates, & Biomes

19. Winds (Air Currents)
Wind is air that is moving because of unequal heating in the atmosphere
Usually flow from high pressure area to low
Moves heat, moisture, soil, and pollution around the planet

20. Tradewinds
Named for their ability to quickly propel trading ships across the oceans
TW that blow between 30 deg latitude & the equator are steady, strong & travel at a speed of mph
Northeast Tradewinds in the Nothern Hem.
Move south and west of the equator
Southeast Tradewinds in the Southern Hem.
Move north and west of the equator

21. Pic: Tradewinds across Pacific

22. Westerly
Moving air mass near the equator between 30 deg and 60 deg as a result of the Coriolis Effect
Northern hemisphere
Travels north and east
Southern hemisphere
Travels south and east

23. Polar Easterlies
Wind pattern formed from forces similar to the Coriolis Effect
Northern Hemisphere
Lie in latitudes between 60 degrees and the North Pole
blow south and west
Southern Hemisphere:
Lie in latitudes between 60 degrees and the South Pole
blow north and west

24. Pic: Tradewinds & Westerlies

25. Horse Latitudes (Subtropical Highs)
Air movement is less predictable
Could have no wind for days
Between latitudes of degrees No & So of equator
Region of subsiding dry air and high pressure resulting in very weak winds

26. Intertropical Convergence Zone ITCZ (Doldrums)
Air near the equator that is relatively still because the air is constantly rising & not blowing
Exist between 5 degrees No & So of the equator
Tradewinds converge here producing convectional storms that produce regions that have some of the heaviest precipitation in the world

27. Jet Stream
High speed currents of wind that occur in the upper troposphere
Have a large influence on local weather patterns

28. Pic: Winds & Hadley Cells

29. Pic: Horse Latitudes, ICZ, TW, W, PE

30. Weather Events Monsoons Rain Shadow Effect Tropical Storms Hurricanes
Typhoons
El Nino
Southern Oscillation
La Nina