1. biomes
What factors determine biomes?

2. Global Climates and Biomes
Chapter 4

3. Global Processes Determine Weather and Climate
Weather represents short-term, local change in temperature, humidity and precipitation.
It can only be predicted a few days in advance
Climate is a long-term pattern of average weather that occurs in a region. General predictions can be made.
Regional differences in climate determines which organisms can survive in a given region.

4. atmosphere details more dense at surface of earth
78% nitrogen, 21% oxygen gas, 1% = argon, neon, helium, methane, hydrogen krypton and carbon dioxide.
water vapor = 0.4% near earth’s surface

5. temperature fluctuates greatly
Earth’s Atmosphere
temperature fluctuates greatly
all weather

6. Name the layers of the atmosphere in order starting at Earth’s surface.
In which layer is the ozone located?
In which layer does weather occur?
What are the major gases and their amounts in the atmosphere
Where is the atmosphere most dense?
What is ozone?
How does the ozone layer affect earth?
What class of chemicals depletes ozone?
How might soil type affect biomes?

7. Reasons for the Unequal Heating of Earth
Angle of insolation varies the amount of energy that strikes the surface of the Earth. (FIGURE 4.3, PAGE 90)
The Sun strikes the tropics at a perpendicular angle. Mid-latitude and polar regions receive solar energy at more oblique angles.
Solar energy is lost as it passes through the
atmosphere. Solar energy travels shorter distances through the atmosphere at the tropic regions.

8. Reasons for the Unequal Heating of Earth
Variation in the amount of surface area receiving solar energy
Light at the mid-latitude and polar regions is distributed over a large surface area, giving each square meter of surface less energy.

9. Reasons for the Unequal Heating of Earth
Different surfaces have different albedo values based on how much light they absorb or reflect.
A white surface has a higher albedo than a black surface.
Earth has an average albedo value of 30%.
The tropics have albedo values that range from 10-20%
The snow covered polar regions have albedo values that range from 80%-95%
FIGURE 4.4, PAGE 90

10. Atmospheric Convection Currents
Properties of air that determine how it circulates: Density, water vapor, adiabatic heating/cooling and latent heat release.
Less dense air rises
Warmer air is less dense than colder air
Warmer air can hold more water vapor than cooler air.
The saturation point is the maximum amount of water vapor that air can hold at a given temperature.

11. Adiabatic Heating & Cooling
In addition to temperature, air responds to changes in pressure.
Air under lower pressure expands and this expansion causes the temperature to decrease. This is adiabatic cooling.
Adiabatic heating happens when cool air sinks, the pressure increases and this causes the temperature of the air mass to increase.

12. Latent Heat Release
It takes solar energy to convert liquid water to gaseous water vapor.
When water vapor condenses back to a liquid this heat is released from the water into the atmosphere.

13. How Convection Currents Form
Global patterns of air movement are initiated by unequal heating of Earth.
moist air is warmed and rises at the equator
Lower air pressure at high altitudes causes adiabatic cooling,
Air reaches saturation
Condensation forms clouds
This leads to latent heat release
Air continues to rise.
Adiabatic cooling happens again.

14. This cold dry air is displaced horizontally to the North and South as warm air continues to rise from the equator.
This displaced air eventually sinks at 30ْ N/S.
Increased air pressure causes adiabatic heating. This air is hot and dry (leads to deserts)
This air moves horizontally to replace the rising air at the equator- completing the cycle.
These are called Hadley Cells.

15. Earth’s Tilt and Seasons
The Earth’s axis of rotation is tilted 23.5ْ
This causes seasonal changes at the Earth orbits around the Sun

16. The Coriolis Effect
Earth’s rotation influences the directions of prevailing winds .
As the Earth rotates, its surface moves much faster at the equator than in mid-latitude and polar regions.
This difference in rotation speeds causes a deflection of objects that are moving directly north or south

17. Global Winds
The combination of convection cells and the coriolis effect create distinct wind patterns
The trade winds or ‘easterlies’ originate from the east and flow from the 30 N/S latitude towards the equator.
The Doldrums are where the trade winds converge at the ITCZ
Westerlies are winds that originate from the west and flow pole ward from 30 N/S to 60 N/S.
Polar easterlies originate from east and flow from the poles toward lower latitudes. 90 N/S to 60 N/S.

18. Rain Shadow Effect
These are created when global winds carry warm moist air onto the coast and the air mass encounters a mountain range
Windward side: Here warm air rises and adiabatic cooling leads to cloud formation and precipitation.
Leeward side: Here cold dry air descends and adiabatic heating creates hot dry conditions.
Watch this video about Death Valley as an example of the rain shadow effect.

19. Ocean Currents Influence Climate
Currents are driven by a combination of temperature differences, gravity, prevailing winds, the Coriolis effect, and locations of continents.
Warm water at the equator rises, while water at mid-latitudes remains at lower elevations. This gradient causes water to flow away from the equator
Gyres: Circulation patterns that redistribute heat in the ocean.
Flow is clockwise in Northern Hemisphere
Flow is counterclockwise in Southern Hemisphere.
Watch this video to better understand how ocean currents affect climate

20. Upwelling: deep waters rise to the surface and circulate nutrients and oxygen.
This happens along the western coasts of continents where surface currents diverge.
Leads to increased productivity in the ocean.
Thermo-haline Circulation: circulation is driven density differences based on temperature and salinity
This creates a great ocean conveyor belt that takes hundreds of years to complete.
One concern about global warming is that increased ice melt could make the North Atlantic less salty, and less likely to sink. This might shut down thermo- haline circulation.
Vertical Circulation

21. Ocean Currents Transport Heat
The Gulf Stream originates in the tropics near the Gulf of Mexico.
It flows Northeast and across the Atlantic Ocean towards Europe.
It brings heat to higher latitudes that would otherwise be much cooler.
Watch this video about the Gulf Stream

22. El Niño- Southern Oscillation - ENSO
Approximately every 3-7 years surface currents in the tropical Pacific Ocean reverse.
Movement of warm water and air toward South America suppresses upwelling and decreases productivity.
Globally this causes cooler and wetter conditions in the southeast U.S. & dry weather in southern Africa and southeast Asia.

23. Various Biomes are Identified by the Unique Adaptations in the Dominant Flora & Fauna
Plants that grow in a desert biome need to be adapted for hot & dry weather conditions. Plants need to be able to store water and resist evapotranspiration.
Organ pipe cactus are found in Arizona.
Euphorbia grow in Namibia. They have similar growth pattern as the cactus, but they possess distinctly different flowers and spines. Only members of the Euphorbia family produce a milky sap.

24. Climate Diagrams
Visualize annual temperature and precipitation of a given area or biome.
We can look for seasonal patterns.
Rainy times of the year
Growing season
How humans might use different biomes: farming or lumber.