1. Climate: Causes and Classification

2. What is CLIMATE?
Long-term weather patterns for an area (climatology)
Variations in temperature, precipitation, and winds throughout the year

4. What causes CLIMATE?
An area’s climate is caused by a combination of 4 factors:
Latitude
Topographic Effects
Air masses
Side of Mountain Range

5. 1st Cause of Climate: Latitude
Most important cause!
The latitude (how far North or South of the equator) determines how much solar radiation an area receives due to Earth’s tilt
Equator = little tilt = high direct sunlight
Poles = high tilt = little direct sunlight

6. 2nd Cause of Climate: Topographic Effects
Land vs. Water (distance to water)
Coastal areas = wetter and moderate temperatures
Inland areas = drier and more extreme temperatures
Elevation
Mountains = cooler
Lower elevations = warmer

7. 3rd Cause of Climate: Air Masses
Same types of air masses move into the same area at the same time each year
Air masses bring the characteristics of their source regions (cP, mT, etc)
Air masses moving in interact with the air masses present to influence climate

8. 4th Cause of Climate: Side of Mountain Range
Windward Side
Moist air rises over a mountain & cools at the top
Wet climate forms
Leeward Side
Cold, dry air sinks down from the mountain & warms at the bottom
Dry/Desert climate forms

9. Koppen Classification System

10. Koppen Classification System
Uses average monthly and annual values of temperature, precipitation, and vegetation to classify climates

11. Koppen Classification System
Contains ~5 main divisions:
Humid Tropical
Dry
Humid Mid-Latitude
Continental
Polar

12. Koppen Classification System: Humid Tropical Climates
Constant high temperatures – no change in seasons
Constant high humidity
High amounts of precipitation
Near the equator

13. Koppen Classification System: Dry Climates
Little to no precipitation
Hot summers & cool winters
Subtypes:
Arid (desert)
Semi-arid

14. Koppen Classification System: Humid Mid-Latitude Climates
Mild winters & warm, humid summers
Abundant (lots of) rain
Subtypes:
Marine
Humid subtropical
Mediterranean

15. Koppen Classification System: Continental
Severe winters & mild summers
Primarily (mostly) located north of the equator
Subtypes:
Temperate
Highlands

16. Koppen Classification System: Polar Climates
Coldest regions on Earth (year-round)
Little precipitation
Winter days are (almost) all darkness; summer days (almost) all daylight
Antarctica