1. Weather and Climate Determine Biomes
Chapter 6
Weather and Climate Determine Biomes

2. Core Case Study Climate Change: India
Severe Droughts
What are farmers doing to insure they can plant and harvest crops?
Figure 5-1

3. Layers of the Atmosphere

4. Layers of the Atmosphere

5. CLIMATE: A BRIEF INTRODUCTION
Weather is a local area’s short-term physical conditions such as temperature, precipitation and wind.
Climate is a region’s average weather conditions over a long time. Data for temperature and precipitation averages are used to determine predicted biomes.
Latitude and elevation help determine climate.
(Latitude is attitude, Longitude is longer dude)

6. Weather examples
Jet stream:
Tornadoes:
Hurricanes:

7. Earth’s Current Climate Zones
Figure 5-2

8. Climates and Biomes Biome Temperature Range Precipitation Polar Ice
S high 50 C, W Avg -27 C
10 inches
Subarctic
5 to 7 months sub zero
15 inches
Cool Temperate
NY, NY: 25 F to 81 F
28 to 62 inches, rain shadow
Highland
Mountains
Varies
Warm Temperate
North Carolina
25 inches
Dry
Range above freezing
< 20 inches
Tropical
64 F all year
28 inches (2.4 in/month)

9. Solar Energy and Global Air Circulation: Distributing Heat
Global air circulation is affected by the uneven heating of the earth’s surface by solar energy causing seasonal changes in temperature and precipitation.
Figure 5-3

10. Students try:
In groups of 5, imitate the photo with a globe and flashlight.
Discussion Questions:
What part of the earth receives the most sun?
Why are seasons different in Australia compared to the US?
What part of the earth receives the least sun?
Why is it dark for large lengths of time in Alaska?
What else did you notice?

11. (sun aims directly at equator)
Winter
(northern hemisphere
tilts away from sun)
Spring
(sun aims directly
at equator)
23.5 °
Solar
radiation
Summer
(northern hemisphere
tilts toward sun)
Figure 5.3
Natural capital: as the planet makes its annual revolution around the sun on an axis tilted about 23.5°, various regions are tipped toward or away from the sun. The resulting variations in the amount of solar energy reaching the earth create the seasons in the northern and southern hemispheres.
Fall
(sun aims directly at equator)
Fig. 5-3, p. 102

12. Heat released radiates to space Moist surface warmed by sun
LOW
PRESSURE
HIGH
PRESSURE
Heat released radiates to space
Condensation
and
precipitation
Cool, dry
air
Falls, is compressed, warms
Rises, expands, cools
Warm,
dry air
Hot, wet
air
Figure 5.5
Natural capital: transfer of energy by convection in the troposphere. Convection occurs when hot and wet warm air rises, cools, and releases moisture as precipitation and heat (right side). Then the more dense cool and dry air sinks, gets warmer, and picks up moisture as it flows across the earth’s surface to begin the cycle again.
Flows toward low pressure,
picks up moisture and heat
HIGH
PRESSURE
Moist surface warmed by sun
LOW
PRESSURE
Fig. 5-5, p. 103

13. Demo: Humidity Dew point: Temperature at which water vapor condenses
Relative Humidity: the amount of water vapor in a mixture of air and water vapor, when it reaches 100% we say the air is saturated.
Clouds creation and beaker Demo
Phet: gas-properties_en (1)

14. Tropical deciduous forest
Cold,
dry air
falls
Cell 3 North
Moist air rises — rain
Polar cap
Cell 2 North
Arctic tundra
Evergreen
coniferous forest
60°
Cool, dry
air falls
Temperate deciduous
forest and grassland
30°
Desert
Cell 1 North
Tropical deciduous forest
Moist air rises,
cools, and releases
Moisture as rain 0°
Equator
Tropical
rain forest
Tropical deciduous forest
30°
Desert
Cell 1 South
Figure 5.6
Natural capital: global air circulation and biomes. Heat and moisture are distributed over the earth’s surface by vertical currents, which form six giant convection cells at different latitudes. 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 biomes.
Temperate deciduous
forest and grassland
Cool, dry
air falls
60°
Cell 2 South
Polar cap
Cold,
dry air
falls
Moist air rises — rain
Cell 3 South
Fig. 5-6, p. 103

15. Cold deserts Westerlies Forests Northeast trades Hot deserts Forests
Equator
Figure 5.4
Natural capital: because of the Coriolis effect the earth’s rotation deflects the movement of the air over different parts of the earth, creating global patterns of prevailing winds that help distribute heat and moisture in the troposphere.
Southeast trades
Hot deserts
Forests
Westerlies
Cold deserts
Fig. 5-4, p. 102

16. Coriolis

17. Topography and Local Climate: Land Matters
Interactions between land and oceans and disruptions of airflows by mountains and cities affect local climates.
Figure 5-8

18. Dry habitats Moist habitats
Prevailing winds
pick up moisture
from an ocean.
On the windward
side of a mountain range,
air rises, cools, and
releases moisture.
On the leeward side of
the mountain range, air
descends, warms, and
Releases little moisture.
Dry habitats
Moist habitats
Figure 5.8
Natural capital: The rain shadow effect is a reduction of rainfall on the sides of mountains facing away from prevailing surface winds. Warm, moist air in prevailing onshore winds loses most of its moisture as rain and snow on the windward (wind-facing) slopes of a mountain range. This leads to semiarid and arid conditions on the leeward side of the mountain range and the land beyond. The Mojave Desert in the U.S. state of California and Asia’s Gobi Desert were both created by this effect.
Fig. 5-8, p. 105

19. Sea Breezes: Day

20. Sea Breeze: Day Vs. Night

21. BIOMES: CLIMATE AND LIFE ON LAND
Different climates lead to different communities of organisms, especially vegetation.
Biomes – large terrestrial regions characterized by similar climate, soil, plants, and animals.
Each biome contains many ecosystems whose communities have adapted to differences in climate, soil, and other environmental factors.

22. BIOMES: CLIMATE AND LIFE ON LAND
Figure 5-9

23. Tropic of Cancer Equator Tropic of Capricorn High mountains Polar ice
Polar grassland (arctic tundra)
Tropic of
Capricorn
Temperate grassland
Figure 5.9
Natural capital: the earth’s major biomes—the main types of natural vegetation in various undisturbed land areas—result primarily from differences in climate. Each biome contains many ecosystems whose communities have adapted to differences in climate, soil, and other environmental factors. Human ecological footprints (Figures 3 and 4 on pp. S12–S15 in Supplement 4) have removed or altered much of the natural vegetation in some areas for farming, livestock grazing, lumber and fuelwood, mining, and construction.
Tropical grassland (savanna)
Chaparral
Coniferous forest
Temperate deciduous forest
Tropical forest
Desert
Fig. 5-9, p. 106

24. Recognizing Climates:
In the biome map the southern tip of South America is brown, but the northern is green. Come up with a hypothesis why that happens.