1. Chapter 4 .1 What Causes Climate?

2. Climate vs. Weather
Weather is the condition of the atmosphere at a particular time and place
Climate is the average, year after year conditions of temperature, precipitation, winds and clouds in an area

3. What factors determine the climate of a region?
Two factors determine climate:
Temperature
Precipitation
Climate region – is a large area with similar climate conditions throughout

5. Factors affecting Temperature
Latitude
Farther from the equator, the cooler the climate
Tropical zone 23.5 degrees North and South of the equator
Temperate zone degrees North and South of the equator
Polar zone: degrees

6. Factors affecting temperature
Altitude:
high mountains will have cool climates independent of where the latitude is
ex. Mt Kilimanjaro in Africa has snow on its top even though it is 3 degrees from the equator.

7. Factors affecting Temperature
Distance from large bodies of water
Coastal areas have a marine climate (water heats up more slowly than land; it also cools down more slowly) warm winters, cool summers
Because of winds from the ocean, temperature extremes are not common.

8. Factors affecting Temperature
Continental climates - areas too far inland to be warmed or cooled by the oceans.
Interior areas of the US, Canada, Russia
have a more extreme climate, hot summers, bitterly cold winters

9. Factors affecting temperature
Ocean Currents – streams of water within the oceans that move in regular patterns.
“Warm” water currents originate from the Equatorial regions and move North or South
ex. Gulf Stream ( best known water current)
“Cold’ water current originate in the Polar regions and move south making climates cooler
ex. California current

11. Factors affecting Precipitation
Prevailing Winds
Air masses are moved by the prevailing winds. Air masses may be hot or cool, wet or dry.
Ex. Air masses near the equator are hot and humid, produce lots of rainfall and have thick vegetation
Ex. Winds blowing over land (trade winds in Africa), carry little moisture and produce deserts

12. Factors affecting Precipitation
Mountain Ranges
The presence of a mountain range will act to force air to move up the mountain side,
On the windward side the air is cooled and drops its moisture as rain or snow
on the leeward side the air is dryer producing desert like environments.

14. Microclimates Sometimes a small area (ex wooded park)
has a climate all its own because the moisture from transpiration from trees in the park keeps it cooler and more humid than the surrounding city environment.
This is called a microclimate

15. The Seasons Affected by the tilt of the earth’s axis (23.5)
Winter and summer are determined by the tilt towards (summer) or away (winter) of each hemisphere