Wind What are winds?

Global Wind Patterns Circulation of air caused by pressure and temperature Polar regions are high pressure zones Equator is a low pressure zone Warm air is less dense, and rises Cold air is more dense, and sinks

Circulation Affected by Earth’s Rotation Northern Hemisphere deflects to the right Southern Hemisphere deflects to the left This is caused by the Coriolis Effect

Movement Low pressure, warm air rises at the equator 30 degrees N and S latitude = high pressure zone, air cools and sinks Three looping patterns are convection cells Convection the heating and cooling of gas particles

Trade winds Between the Equator and 30 ° N and S latitude Northeast trade winds Southeast trade winds

Trade winds Doldrums: Warm air moves upward Surface winds weak and undependable How does this affect sailing? Subtropical High Pressure Belt = Horse Latitudes Why is this called the HORSE LATITUDES?

Westerlies Northern Hemisphere = South westerlies Southern Hemisphere = North westerlies 30° to 60° Creating the Subtropic Jet Stream Constant flow of wind

Polar Easterlies Strongest off of Antarctica Very stormy region Sub polar Jet Stream = Inconsistent movement of air 10- 15 km altitude, 100 km wide, 2-3 high Moves at up to 500 km/hr Determine the flight path of planes

Wind and Pressure Shifts Pressure belts and Wind belts shift throughout the year Why : location of the sun’s rays

Local Winds Breezes: the movement of air that extends over a distance less than 100 km

Breezes Land and water receive the same amount of energy (heat) from the sun Land heats up and cools down faster than water Differences in temperature create local winds

Sea Breeze Cool wind moving from water to land Cool air is more dense than warm air Cool air over water replaces warm air over land When would this occur? Afternoon

Land Breeze Cool wind moving from land to water Cool air is more dense than warm air Cool air over land replaces warm air over water When would this occur? At night

Valley Breeze Breeze blowing up the slope of a mountain Warm air in valley rises up the mountain (cooler air) When would this occur? Daylight

Mountain Breeze Breeze blowing down the slope of a mountain into the valley Cool air in the mountains overtake warm air in the valley When would this occur? At dusk or sunset