1. Causes of Weather Chapter 12 Section 1

2. Meteorology Study of atmospheric phenomenon Meteor – Anything high in the sky Rain droplets Clouds Rainbows snowflakes

3. Weather vs. Climate Weather Short-term atmospheric phenomena that interact and interfere in the environment Climate Long-term average of variations in weather for a particular area

4. Heating Earth’s Surface Imbalanced heating – Earth’s axis of rotation is tilted relative to the plane of Earth’s orbit

5. Thermal Energy Redistribution Areas maintain the same average temperatures over time due to the constant movement of air and water over the surface. Weather moves thermal energy over the planet.

6. Air Masses Conduction- warm air rises and cool air sinks Warm air is less dense than cool air Air Mass: – A large volume of air that has the same characteristics of its source region.

7. Tropical Air Masses Maritime tropical air originates over bodies of water – Gulf of Mexico – Caribbean Sea – Tropical and subtropical Atlantic and Pacific Oceans – Brings hot humid weather to eastern 2/3 of North America Continental Tropical Air originates in Mexico and Southern United States. – Hot and dry

8. Polar Air Masses Maritime Polar Air Masses – Form over cold waters of the North Atlantic and North Pacific

9. Polar Air Masses Continental Polar Air Masses for over the interior of Canada – Cold frigid temperature in winter – Brings relief to hot summers

10. Arctic Air Masses Arctic Air Masses originate over snow covered surfaces above 60⁰ N Latitude – Areas get almost no solar radiation – Extremely cold especially during the winter

11. Air Mass Modification Air masses move constantly Thermal energy is transferred from one area to another when they move Air masses can take on characteristics of another region as it travels over it Modification occurs when this happens – Thermal energy is exchanged with the surface it travels over