1. 12.1 notes: The Causes of Weather
Main Idea 1: Weather is affected by winds carrying air masses.

2. Air Masses Characteristics Temperature:
Determined by the amount of solar radiation received & the heat capacity of the area over which it forms.

3. Air Masses Characteristics Humidity:
Measurement of moisture content in the
air.

4. c= Continental m= Marine
Four Major Types of Air Masses: (T) tropical cT Warm, Dry mT Warm, Wet (P) polar cP Cool, Dry mP Cool, Wet

5. Map example of air masses

6. Long term variations of the weather in a region.
It’s the average of 30+ yrs. or more of “weather”.
Weather vs Climate: The current state of the atmosphere. Ie.. short-term variations in a region.

7. Bubble Concept Map of Weather Vs
Bubble Concept Map of Weather Vs. Climate to help you see the different factors.

8. Balancing The “Budget”:
Due to continual air movement & ocean circulation, heat energy is constantly moving between air, land, & water.
Heat is always being redistributed around the globe.

9. The Ocean’s Conveyor Belt:
The Earth’s “Air conditioner”
The Earth’s Major Winds

10. Main Idea 2: The large water or land area over which an air mass forms is called the source region.

11. Air Masses:
Describe: A large body of air that takes on characteristics of the area over which it forms.

12. Classify Air Masses: . Warm, dry = formed over land, near tropics.
Cold, dry= formed over land, near poles.
Warm, wet= formed over ocean, near tropics.
Cold, wet = formed over water, near poles. .

13. Source Regions:
Ex A: A huge, empty parking lot at Disney World in July = hot, dry air mass!
Ex B: Malaspina Glacier near the ocean= cold, wet.

14. Air Mass Modifications:
Always on the Move: Air masses do not
stay in one place forever!
Describe Modification: When an air mass moves over new land or water, it acquires new characteristics from the new surface beneath it.