1. Ch. 6 and 7 Weather, Climate and Biomes
Mr. Lesley APES

2. Weather
The short-term day-to-day changes in temperature, air pressure, humidity, precipitation, sunshine, cloud cover and wind direction and speed.
Most weather is predicted using:
weather balloons, aircraft, radar, and satellites

3. Weather Changes
Air Masses: large lump of air that similar temperature and moisture level throughout.
Air Masses that effect the US are

4. When air masses meet it causes changes in weather
Cold front: when a cold air mass collides with a stationary warm air mass. The result is: thunderstorms, short bursts of heavy rain

5. Warm Front:
when a warm air mass collides with a stationary cold air mass. The result is: warm steady rain

6. Weather is also affected by changes in atmospheric pressure
High pressure has descending air that moves outward from the center of the high-pressure system. Descending air is warm and dry. The result is: nice dry weather

7. Low pressure
has ascending air that flows towards the center of the low-pressure area. Ascending air-cools and condenses as it rises. The result is: clouds, rain

8. Weather Extremes
Hurricanes:
What is it? Tropical storm with winds greater than 75 mph
The bad: loss of life and property
The good: flushes out coastline

9. Tornadoes:
Form when cold dry air collides with warm moist air, which causes the warm air to rise quickly making a funnel cloud

10. Prince Williams
Sound
Gulf of Alaska
Risk of Tornadoes
CANADA
Highest
High
Medium
UNITED STATES
Low
Grand Banks
Hurricane Frequency
High
Moderately
high
Atlantic
Ocean
MEXICO
Fig. 6.2, p. 122

11. Climate
Climate is the long term average precipitation and temperature of an area
Climate is determined by global wind patterns, latitude, altitude and ocean currents

12. Average Precipitation
Climate 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
Fig. 6.3, p. 123
where people live
how people live

13. Polar (ice)
Warm temperate
Highland
Warm ocean current
Subarctic (snow)
Dry
Major upwelling zones
Cold ocean current
Cool temperate
Tropical
River
Fig. 6.4, p. 124

14. Global Air currents affect regional climates
Uneven heating of the Earth’s surface causes the equator to receive more sunlight making it hotter; the poles receive less light making them cooler. This causes: global circulation

15. near the earth’s surface
Easterlies
(from the east)
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 
Fig. 6.6b, p. 125

16. Cold Tropical (equator) Tropical Cold Climate type
Cool Temperate
Warm Temperate
Tropical
(equator)
Tropical
Warm Temperate
Cool Temperate
Cold
Fig. 6.6a, p. 125
Climate type

17. Seasons
Seasonal changes in temp and precipitation affect climate because the earth is tilted on its axis. It is colder in the winter and warmer in the summer because:

18. (sun aims directly at equator)
23.5
Spring
(sun aims directly
at equator)
Winter
(northern hemisphere
tilts away from sun)
Solar
radiation
Summer
(northern hemisphere
tilts toward sun)
Fall
(sun aims directly at equator)
Fig. 6.5, p. 124

19. Coriolis Effect
Rotation of the Earth on its axis prevents air currents from moving directly north or south causing the winds to curve in what is called:

20. Ocean Currents
Long term variations in the amount of incoming solar radiation
Heat from the sun evaporates water and transfers energy from the ocean to the atmosphere. This creates convection cells that transport heat to different latitudes. This leads to: ocean currents and weather

21. Polar (ice)
Warm temperate
Highland
Warm ocean current
Subarctic (snow)
Dry
Major upwelling zones
Cold ocean current
Cool temperate
Tropical
River
Fig. 6.4, p. 124

22. Ocean Currents Affect climate
Differences in water temp, winds and the rotation of the earth create currents.
Currents redistribute heat. For example the gulf stream brings heat to Europe

23. Upwelling is created when the trade winds blow offshore pushing surface water away from land. The outgoing surface water is replaced by nutrient bottom water. Upwelling support:

24. Wind Upwelling Nutrients
Movement of
surface water
Diving birds
Fish
Upwelling
Zooplankton
Phytoplankton
Nutrients
Fig. 6.9, p. 126

25. The El Nino Southern Oscillation occurs every few years in the Pacific Ocean
In an ENSO, prevailing westerly winds weaken or stop
Surface waters along the coast of North America and South America (west) become warmer
Normal upwelling stops
This reduces the population of some fish species
Also causes severe weather, storms in the US especially CA, and drought in southeast Asia

26. Warm water Thermocline Cold water Normal Conditions
Surface winds
blow westward
EQUATOR
Warm waters
pushed westward
SOUTH
AMERICA
AUSTRALIA
Warm water
Thermocline
Cold water
Normal Conditions
Fig. 6.10a, p. 127

27. Temperature/Change (°F)+3
El Nino conditions
1982–83
1997–98
La Nina conditions +2 +1
Temperature/Change (°F) -1 -2
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
Year
Fig. 6.12, p. 128

28. Warm water Thermocline Cold water El Niño Conditions
Winds weaken,
causing updrafts
and storms
Drought in
Australia and
Southeast Asia
EQUATOR
Warm water
flow stopped
or reversed
SOUTH
AMERICA
AUSTRALIA
Warm water deepens off
South America
Warm water
Thermocline
Cold water
El Niño Conditions
Fig. 6.10b, p. 127

29. El Niño Drought Unusually high rainfall Unusually warm periods
Fig. 6.11, p. 127

30. La Nina
La Ninas follow an El Nino and are characterized by cooling trends. La Nina brings more Atlantic hurricanes, colder winters in the north and warmer winters in the south, and an increase in tornadoes.

31. The chemical makeup of the atmosphere affects the weather.
Small amounts of water vapor, carbon dioxide, ozone, methane, nitrous oxide and chlorofluorocarbons trap heat in the atmosphere warming the planet. These gases are called: greenhouse gases
The greenhouse effect is when greenhouse gases allow light, infrared radiation and UV radiation through to the surface of the earth where it is reflected back into space. The greenhouse gases trap some reflected infrared radiation

32. As concentrations of greenhouse
Rays of sunlight penetrate the lower atmosphere and warm the earth's surface.
(b)
The earth's surface absorbs much of the incoming solar radiation and degrades it to longer-wavelength infrared radiation (heat), which rises into the lower atmosphere. Some of this heat escapes into space and some is absorbed by molecules of greenhouse gases and emitted as infrared radiation, which warms the lower atmosphere.
(c)
As concentrations of greenhouse
gases rise, their molecules absorb and emit more infrared radiation, which adds more heat to the
lower atmosphere.
Fig. 6.13, p. 128

33. Ozone Layer
The ozone layer is located in the stratosphere. It is created when ultraviolet light turns oxygen into ozone. The chemical reactions is:
Ozone blocks all short wavelength UV-C radiation, 50% of the UV-B radiation and almost no long wavelength UV-A radiation.
Ozone also forms a thermal cap which: traps heat

34. Topography of the earth also creates microclimates
A microclimate is small area that has a different climate than the general climate of an area.
Vegetation in an area influences climate: forests stay warmer in the winter and cooler in the summer because of the trees
Cities create heat islands that trap heat and decrease wind speeds

35. Water also changes climate by causing land breezes and sea breezes
Cool air
descends
Warm air ascends
Land warmer than
sea; breeze flows
onshore
Fig. 6.15a, p. 130

36. Cool air descends Warm air ascends Land cooler than sea; breeze flows
offshore
Fig. 6.15b, p. 130

37. The rain shadow effect changes climate
a Winds carry
moisture inland
from Pacific Ocean
b Clouds, rain on
windward side of
mountain range
c Rain shadow on
leeward side of
mountain range
4,000/75
3,000/85
2,000/25
1,800/125
1,000/25
Moist habitats
1,000/85
15/25
The rain shadow effect changes climate
Fig. 6.14, p. 129

38. Arctic tundra (polar grasslands) Desert
Tropic of
Cancer
Equator
Tropic of
Capricorn
Semidesert,
arid grassland
Arctic tundra (polar grasslands)
Desert
Boreal forest (taiga), evergreen coniferous
forest (e.g., montane coniferous forest)
Tropical rain forest,
tropical evergreen forest
Mountains
(complex zonation)
Temperate deciduous forest
Tropical deciduous forest
Ice
Temperate grassland
Tropical scrub forest
Fig. 6.16, p. 131
Dry woodlands and
shrublands (chaparral)
Tropical savanna,
thorn forest

39. Polar Subpolar Temperate Tropical
Tundra
Subpolar
Temperate
Coniferous forest
Desert
Deciduous
forest
Grassland
Chaparral
Tropical
Desert
Savanna
Rain forest
Tropical
seasonal
forest
Scrubland
Fig. 6.17, p. 132

40. Temperate Deciduous Forest Northern Coniferous Forest Arctic Tundra
Low
Alpine
Tundra
Montane
Coniferous
Forest
Elevation
Deciduous
Forest
Tropical
Forest
High
Tropical Forest
Temperate Deciduous Forest
Northern Coniferous Forest
Arctic Tundra
High
Moisture Availability
Low
Fig. 6.18, p. 133

41. Plant and animal adaptations to climate
For plants precipitation is generally the limiting factor in determining whether a climate is a desert, forest or grassland, but biomes are not uniform. They have the same general characteristics but there are microclimates that determine the actual plants you will find in any given area.

42. Plants exposed to cold year around or in the winter have:
Traits that keep them from losing too much heat or water
They stay small

43. Desert plants must be able to lose heat and conserve water
Desert plants must be able to lose heat and conserve water. They do this by:
Lose heat and store water
Fleshy tissue, vertical, no leaves, store water

44. In wet tropical climates the plants have
Broadleaf evergreen, maximize sunlight

45. In climates that are hot in summer and cold in winter, plants have:
Deciduous leaves that fall off in winter

46. In areas with cool short summers, the trees have:
Coniferous evergreen
Needle shaped leaves