The tilt of the Earth's axis as it revolves around the sun causes the seasons.

1. Climate Regions

2. What is Climate?
 Weather is the day-to-day changes in
atmospheric conditions
 Climate is long-term weather conditions
 Temperature and precipitation are the most
important expressions of climate

3. What aspects of the environment are
influenced by climate?
 Vegetation
 Animal life
 Soils
 Landforms
 Water resources

4. Ecosystems
 What is an ecosystem?
 An area of interaction between plants,
animals,and their environment
 Unique ecosystems evolve as a result of
differing climate conditions
 Climatology studies the climate regions that
have evolved in response to different moisture
and temperature conditions

5. What is the Impact of Climate Upon
People’s Lives?
 Regions of climatic handicap have few
people
 deserts, rainforests, polar regions
 Climate influences agriculture - the choice of
crops grown and animals raised
 Tourism and recreation
 Water resources
 Climate and disease

6. Does Climate Affect Temperament?
 Aristotle - the nations in cold places are full of
spirit but deficient in intelligence and skill
 Jean Bodin - Northern peoples physically vigorous
but mentally slow
 Hot South - lazy, but politically passive and satisfied
living under despots
 Temperate zone - ideal mix of intelligence and
industry favoring monarchy
 Buckle - Mild, moist British climate favors the
steady work and perseverance of the English

7. Does Climate Repeat Itself?
Koppen’s Climate Region Map

8. Can we make any generalizations?
 Latitude
 Single most important factor-Why?
 Maritime versus continental locations
 Windward coasts have cooler summers and warmer
winters
 Precipitation related to pressure and
wind belts
 High pressure – dry, Converging winds - rainy
 Mountains have different climates
 Mountains are cooler than lowlands

9. Greek’s Climate Regions
Latitude Frigid
Temperate
Torrid
Temperate
Frigid

10. Maritime and Continental Climates
Continental climates are
under the influence of
winds from the
continental interior
Crescent City New York
Maritime climates are Chicago
under the influence of Continental
westerly winds climate
dominated by
continental
Cold California
temperatures
Current brings
cooler
temperatures to the
coast in summer

11. Herbertson’s Climate Regions

12. Herbertson’s Regions
v Isotherms reflect influence of land and
sea
v Polar climates cooler than 50 F in the
warmest month
v Tropical climates warmer than 65 F all
year - winterless
v Middle latitude climates are
changeable

13. Pressure and Wind Belts
What is the climate of each of these pressure and wind belts?
 Polar High
 Polar Easterlies
 Polar Front
 Westerlies
 Subtropical
High
 N E Trade
Winds
 Intertropical
Convergence
Zone
 SE Trades

14. What happens to all these pressure
and wind belts?
 They shift north and south with the overhead
sun
 Do they shift as far north and south as the
Tropics of Cancer and Capricorn?
 No, about 5º N and 5º S

15. Where in the World is it Raining Today ?
The world’s rainy places coincide with
global pressure and wind belts

16. Three Major Rain Belts
 The Northern Hemisphere Polar Front
 Midlatitude Cyclonic Storms - low pressure
 The Intertropical Convergence Zone (ITCZ)
 Trade winds converge along the equatorial low
 Convectional lifting produces cumulus clouds
 The Southern Hemisphere Polar Front
 Midlatitude Cyclonic Storms - low pressure

17. Animation Showing Monthly Rainfall

18. Mean Annual Precipitation
STH STH
STH STH
STH

19. Africa’s Climate Regions
Tropic of Cancer
Equator

20. North America Climates

21. Koppen’s Climate Classification
 Most widely used map of climate regions
 Empirical-quantitative approach that uses climate
statistics compiled over 30 years
 Designed with plants in mind
 Each climate is defined according to set values of
mean monthly precipitation and mean monthy
temperature

22. Koppen’s Climate Regions

23. Koppen Classification
 (A) Tropical rainy climates
 Every month over 64.4 F
 (B) Dry climates
 Evaporation exceeds precipitation

24. Koppen Classification
 (C) Mild, humid climates
 Coldest month below 64.4 F but above 26.6 F
 (D) Snowy-forest climates
 Coldest month below 26.6 F but warmest month over
50F
 (E) Polar climates
 Warmest month below 50 F

25. Why is the Bay Area rainy in
winter and dry in summer?
 The jet stream and the Polar Front move into
the Bay Area in winter
 The Subtropical High dominates our weather
in Summer

26. Global Regions of Mediterranean and Marine
west-coast “C” climates.
Mediterranean Climate Zones: West coasts ~30-40° Latitude

27. Global Regions of Moist Subtropical Climate
East coasts ~25-35°
Latitude.

28. East vs. West Coast Climates
Mediterranean Climate in Moist subtropical climate in
Monterey, CA Charleston, South Carolina.

29. West Coast Precipitation
Dry summer wet
winter ~30-40°
Dry all year
~20-30°
Dry summer wet
winter ~30-40°

30. Reality Check
 Most climates between the
tropics of Cancer and  Does the U.S. have any A
Capricorn are: (tropical moist) climates?
 Which major climate group is  Does the U.S. have a BWh (hot
not in the Southern desert)?
hemisphere?  What major climate group
 Which major group forms the dominates Canada and
cold summer climates of the Russia?
Arctic?  What climate makes up most of
 Which climates are dry? Western Europe?
 What climate dominates  What climate is not classified
Australia? using Koppen?

31. Berkeley and San Jose Climographs
Annual rainfall – 22.3 inches Annual rainfall – 14.6 inches

32. Review Questions
1. What do clouds need in addition to saturation?
Cloud condensation nuclei
2. Consider the topographic profile diagrammed below.
C
Prevailing winds
A B
Ocean
This would induce what “type” of lifting?
What is the process that causes condensation?
How would the amount of precipitation at A, B, and C
compare?

33. C
Prevailing winds
A B
Ocean
rain shadow
Point B above is said to be in the ________________ of the
mountain shown.
What type of local wind is commonly experienced at B? Is it
a hot or cold wind?
Chinook wind. It’s a hot wind.

34. What is the cause of the seasons?
 Tilt of earth’s axis as it orbits the sun
 Revolution
 Parallelism