1. Global Climates and Biomes
Chapter 4
Global Climates and Biomes

2. Floods, Droughts and Famines
Western Kenya - April 2003 – heavy rains
Flooded villages, roads, bridges
Results…
People could not recover or start rebuilding
In northern Kenya – drought resulting from lack of summer rain
Rains did not come until 2006
What happened??
Global processes drive rainfall patterns
Not understood why the rain clouds did move northward in 2003

3. Global Processes Determine Weather and Climate
Include temperature, humidity, clouds, precipitation, wind speed and atmospheric pressure
Cannot predict weather more than a few days
Climate

4. Earth's Atmosphere 5 layers of gases
Troposphere- the layer closest to surface extending roughly 16 km above Earth
Stratosphere- above the troposphere, this extends from roughly 16 to 50 km
Ozone layer
Mesosphere - temperature decreases with altitude
Thermosphere -
Aurora
Exosphere - Outermost layer

5. Unequal Heating of Earth
As the Sun's energy passes through the atmosphere and strikes land and water, it unequally warms the surface of Earth – WHY?
The variation in angle at which the Sun's rays strike
The amount of surface area over which the Sun's rays are distributed
Some areas of Earth reflect more solar energy than others (albedo)

6. Unequal Heating of Earth: Variation in angle at which the Sun's rays strike

7. Unequal Heating of Earth: The amount of surface area over which the Sun's rays are distributed

8. Unequal Heating of Earth: Albedo

9. Atmospheric Convection Currents
Air has four properties that determines its movement:
Density-
Water vapor capacity- warm air has a higher capacity for water vapor than cold air
Saturation point
Adiabatic cooling-
Adiabatic heating
Latent heat release- when water vapor in the atmosphere condenses into liquid water and energy is released

10. Formation of Convection Currents
Atmospheric convection currents are global patterns of air movement that are initiated by the unequal heating of Earth
Read through explanation on pages for more detail
Hadley cells-

11. Formation of Convection Currents
Intertropical convergence (ITCZ) - the area of Earth that receives the most intense sunlight
Polar cells-
3rd area of air circulation – does not form distinct convection cell

12. Earth's Rotation and the Coriolis Effect
Earth’s rotation has important influence on climate
The surface moves much _______________________ at the equator than in mid-latitude and polar regions

13. Earth's Rotation and the Coriolis Effect
Coriolis Effect- the deflection of an object's path due to Earth's rotation.

14. Earth's Rotation and the Coriolis Effect
The prevailing winds are produced by a combination of atmospheric convection currents and the Coriolis effect
Trade winds
Westerlies
Easterlies

15. Earth's Tilt and the Seasons
Earth's axis of rotation is tilted 23.5˚
Earth’s orbit therefore causes most regions to experience seasonal changes

16. Earth’s Seasons

17. Ocean Currents Ocean currents are driven by a combination of:
Warm water, like warm air, expands and rises.
Gyres- the large-scale patterns of water circulation
Redistribute heat in the ocean

18. Upwelling
Upwelling- as the surface currents separate from one another, deeper waters rise and replace the water that has moved away
Important!

19. Oceanic Circulation

20. Thermohaline Circulation
Thermohaline circulation- oceanic circulation that drives the mixing of surface water and deep water
Takes hundreds of years to complete

21. Heat Transport
Ocean currents can affect the temperature of nearby landmasses
Concern about global warming

23. El Nino-Southern Oscillation
Interaction of the Earth's atmosphere and ocean cause surface currents in the tropical Pacific Ocean to reverse direction
Occurs every 3 to 7 years
Video to check out:
(start ~0:50)

24. El Nino-Southern Oscillation

25. La nina

26. Rain Shadows
Rain shadow – warm, dry air on leeward side of mountain, formed via:
Adiabatic cooling and heating

27. Variations in Climate Determine the Dominant Plant Growth Forms of Terrestrial Biomes
Climate affects the distribution of species
Biomes- areas possessing similar temperature and precipitation patterns
Therefore contain similar producer species

28. Location of World’s Biomes

29. Tundra

30. Boreal Forest

31. Temperate Rainforest

32. Temperate Seasonal Forest

33. Woodland/Shrubland

34. Temperate Grassland/ Cold Desert

35. Tropical Rainforest

36. Tropical Seasonal Forest/Savanna

37. Subtropical Desert

38. Aquatic Biomes are Categorized by Salinity, Depth, and Water Flow
Salinity – amount of salt dissolved in water
Temperature still important…
2 broad categories:
Freshwater
Marine

39. Freshwater Ecosystems

40. Streams and Rivers Flowing fresh water
Originates from underground springs or as runoff from rain or melting snow.
Streams (creeks) - narrow and carry relatively small amounts of water
Rivers - wider and carry larger amounts of water
Water flow affects biological communities
Rapids – stretches of turbulent water in streams and rivers

41. Lakes and Ponds Standing water Lakes are larger than ponds
Distinct zones:
Littoral zone – shallow area of soil and water near shore
Limnetic zone – open water, as deep as light can penetrate
Profundal zone – deep under the limnetic zone where light can no longer reach
Benthic zone – muddy bottom of lake or pond

42. Lakes and Ponds

43. Freshwater Wetlands
Aquatic biomes that are submerged or saturated by water for at least part of each year
Shallow enough to support emergent vegetation
Includes:
Very productive biome
Provide several critical ecosystem services
Problem?

44. Marine Ecosystems

45. Salt Marshes Found along the coast in temperate climates
Contain non woody emergent vegetation
One of the most productive biomes in the world
Ecosystem services

46. Mangrove Swamps Found along tropical and subtropical coasts
Contain trees whose roots are submerged in water
Ecosystem services

47. Intertidal Zone Tide conditions: High tides – stable environment
Low tides – harsh environment
Waves that crash onto the shore

48. Coral Reefs Found in warm, shallow waters beyond the shoreline
Coral – tiny animals that secrete a layer of limestone (calcium carbonate) to form external skeleton
But water is relatively poor in nutrients and food
Coral bleaching

49. The Open Ocean – Past the Intertidal Zone
The depth that light can penetrate in the open ocean is dependent on the amount of sediment and algae suspended in the water
Zones:
Photic zone –
Aphotic zone - the deeper water that lacks sufficient light for photosynthesis
Chemosynthesis
Bioluminescence
Benthic zone – ocean floor