What are winds? Local - Caused by changing air masses Global - Caused by the earth's rotation (Coriolis Effect) and movement of warm air away from the equator

Local Winds
Sea Breezes	Land Breezes
Occur on warm sunny days Air over the land heats faster than the air over the cool ocean Warmer air rises Cool air flows in under it to fill the area over the land This air warms and the cycle continues	Occur at night and on cool days Air over water maintains an even temperature Air over land cools faster Cooler air flows from the land out under the warmer ocean air This air warms and the cycle continues
Changes in Pressure	Changes in Temperature
Air flows from high air pressure area toward a low pressure area High pressure usually brings clear weather Low pressure usually brings stormy weather	As air is heated by the sun, it begins to rise Cool air flows in under it and takes it's place This cycle is repeated continuously

Types of Global Winds Doldrums- An area of calm found at the equator. Also called the Intertropical Convergence Zone (ITCZ) Tropical Easterlies - When warm air from the equator rises, it cools, and flows back toward the equator. It appears to flow to the west because of the Coriolis Effect. Prevailing Westerlies - When air moves toward the poles, it flows from west to east. Polar Easterlies - Air over the poles cools and sinks back down, it eventually returns to the equator.

Interesting Facts

• Winds are named for the direction from which they begin, not the direction they flow.
• Tropical Westerlies are also called Trade Winds.
• Think of air pressure like a balloon - when you let go of it, the air rushes out because of the high pressure of the air inside.
• The sea breeze effect explains why it is usually cooler by the oceans or lakes.
• The Prevailing Westerlies wind pattern causes most of the weather changes in the USA.