1. Chapter 4
Biogeography

2. Weather
Short – term properties: Temp., pressure, humidity, precip, sunshine, cloud cover, wind direction/speed
Wind – regulates global temp., transports nutrients, transports harmful pesticides, toxic metals, viruses, bacteria, fungi (coral reef killer), algae (red tides)

3. Climate – general weather over long- term (avg. temp./precip)
Microclimate – local climatic conditions resulting from topographic features of Earth (sea/land breezes, cities)

4. Composition Nitrogen (N2, 78%) Oxygen (O2, 21%) Argon (Ar, 1%)
myriad of other very influential components are also present which include the Water (H2O, 0 - 7%), "greenhouse" gases or Ozone (O3, %), Carbon Dioxide (CO2, %),

5. Factors That Influence Climate
Air Mass
Air Pressure – Gravity on an air mass, measured in millabars, decreases with altitude, low pressure = cloudy stormy weather, high pressure = cool, dense air that descends toward Earths surface and becomes warmer, usually fair weather
Albedo – reflectivity of surface, snow = high, dark = low
Human Activity - Greenhouse Effect - greenhouse gases (water vapor, CO2, ozone, methane, NO2, CFCs) trap heat in the atmosphere warming the planet

6. Greenhouse Effect
Without the natural greenhouse effect, the Earth would be a cold, mostly lifeless planet.

7. Factors That Influence Climate
5. Altitude - 1,000 feet rise in elevation = 3 degrees F drop in Temp., Influence regional climate
6. Angle of Sunlight – Winter for U.S.A closest to sun (Contributes to seasons)
Clouds – collection of water droplets, warm air rises, clouds expand and thus drops in temperature; therefore, it cannot hold as much water

8. Factors that determine global air circulation patterns
- Uneven heating of the Earth’s surface - Seasonal changes occur because the Earth’s axis is tilted.
Fig. 6-8 p. 116

9. Factors That Influence Climate
8. Distance to oceans – heat holding capacity of water is 5 times greater than air
9. Fronts - Cold Front – cold air mass collides with a stationary warm air mass, cold air (ground) replaces warm air (thunderstorms, then cool clear skies) Warm Front – warm air collides with cold air mass, warm air (rising) replaces cool air (clouds, drizzle)

10. Factors That Influence Climate
10. Land Changes – urbanization, deforestation
11. Latitude
12. Location
13. Moisture Content of Air (humidity) – desert
vs. rainforest
14. Pollution
Rotation of Earth – nights get colder, days
warmer with sunlight
Revolution around the sun (Contribute to seasons)

11. Figure 6-9a Page 117 Cold Cool Temperate Warm Temperate Tropical
(equator)
Tropical
Warm Temperate
Cool Temperate
Cold
Climate type

12. b Clouds, rain on
windward side of
mountain range
c Rain shadow on
leeward side of
mountain range
a Winds carry
moisture inland
from Pacific Ocean
Dry habitats
Moist habitats
16. Mountains - Rainshadow Effect - moist ocean air hits mountains produces rain/snow on windward side, dry conditions on other (Nevada)

13. Rain Shadow Effect

14. Factors That Influence Climate
Wind Patterns
a. Coriolis Effect – caused by rotation of Earth on axis, relates to wind patterns, changes directions of winds all around Earth
b. Jet Streams – wind patterns in the upper portion of the troposphere, travel west to east
b. Long term variations in the amount of solar energy
striking the Earth.
*Milankovitch Cycles--Earth’s wobble (22,000 yrs.), tilt (44,000 yrs.) and changes in the shape of the Earth’s orbit (100,000 year cycle)

15. Wind Patterns
c. Hadley Air Circulation Cells – Air heated near the equator rises and spreads out north and south. After cooling in atmosphere, the air sinks back down within subtropical climates. Surface air from subtropical regions returns toward the equator to replace rising air. Tropical - High humidity, high clouds, heavy rains; Subtropical – low humidity, little cloud formation, high ocean evaporation (deserts)

16. Figure 6-9b,c Page 117 Easterlies (from the east) Westerlies
© 2004 Brooks/Cole – Thomson Learning
Easterlies
(from the east)
Figure 6-9b,c Page 117
Westerlies
(from the west)
60°N
Northeast
tradewinds
30°N
(Doldrums)
equator
Southeast
tradewinds
30°S
Westerlies
60°S
Easterlies
Initial pattern of
air circulation
Deflections in the
paths of air flow
near the earth’s surface 

17. Factors That Influence Climate
Ocean Currents- Current redistributes heat
- Upwelling – trade winds blow offshore pushing surface water away from land bringing water from the bottom to the top
- El Nino – 3-5 yrs, Pacific Ocean, surface waters off the coast of North America become warmer, wacky weather, upwelling stops, reduces populations of fish species
- La Nino – water does not move towards U.S., cooling trends, more Atlantic hurricanes, colder winters in the north and warmer winters in the South, increase in tornadoes

18. What is El Nino-Southern Oscillation (ENSO)?
During an El Nino, the prevailing westerly winds weaken or cease.
This causes upwellings to cease.
Surface water along North and South America becomes warmer.
Nutrients are not brought to the surface causing a sharp decline in the numbers of some fish species.
Can trigger extreme weather changes over most of the globe, especially the Pacific and Indian Oceans.

19. Figure 6-13 Page 119 Movement of surface water Wind Diving birds Fish
Upwelling
Zooplankton
Phytoplankton
Nutrients

20. Figure 6-15 Page 120 El Niño Drought Unusually high rainfall
Unusually warm periods

21. ENSO (El Nino Southern Oscillations)
1. El Nino yrs, normal trade winds are reduced causing warmer than normal ocean water to develop off the west coast (Pacific Ocean, wacky weather, upwelling stops, reduces populations of fish species
2. La Nino – water does not move towards U.S., cooling trends, more Atlantic hurricanes, colder winters in the north and warmer winters in the South, increase in tornadoes

22. What is La Nina? Sometimes El Nino is followed by La Nina.
Westerly winds are stronger than normal resulting in more upwellings.
Also results in extreme weather changes over most of the globe.
Colder waters in the pacific
More Atlantic hurricanes

23. Short-Term Climate Changes:
Fig p. 119

24. Hurricanes: Good or Bad?
Negative effects:
Positive effects:
Kill and injure people, property, and agriculture production.
Flush excess nutrients from land runoff
Carve channels through barrier islands allowing huge quantities of fresh seawater to flood bays and marshes which can increase production of commercially important species of shellfish and fish.

25. Biomes
Annual precipitation, temperature, and soil are the most important abiotic factors that influence the location of biomes.

26. Figure 6-6 Page 115 Climate latitude altitude ocean currents is
© 2004 Brooks/Cole – Thomson Learning
Climate
Figure 6-6 Page 115 is
the average weather patterns for an area over
a long period of time (30 - 1,000,000 years).
It is determined by
Average Precipitation
and
Average Temperature
which are influenced by
latitude
altitude
ocean currents
and affects
what they
grow and eat
where people live
how people live