Climate: Causes and Classification

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

What causes CLIMATE? An area’s climate is caused by a combination of three factors: Latitude Topographic Effects Air masses

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 solar radiation Poles = high tilt = little solar radiation

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

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.

Koppen Classification System

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

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

Koppen Classification System: Humid Tropical Climates Constant high temperatures Constant high humidity High amounts of precipitation

Koppen Classification System: Dry Climates Little to no precipitation Hot summers and cool winters Subtypes: Arid Semi-arid

Koppen Classification System: Humid Mid-Latitude Climates Mild winters & warm, humid summers Abundant rainfall Subtypes: Marine Humid subtropical Mediterranean

Koppen Classification System: Continental Severe winters and mild summers Primarily located north of the equator Subtypes: Temperate Highlands

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