Local and Global Winds 22­3.notebook November 28, 2016

Global Winds

Movement of Air

Earth rotates from west to east

The Coriolis Effect­rotation of the earth causes moving things in the Northern Hemisphere to turn in a clockwise motion (veer to the right)

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Local and Global Winds 22­3.notebook November 28, 2016

Winds move from areas of high pressure to areas of low pressure because the earth's surface is not flat, there is unequal heating of its surface.

The most radiation is received at the equator and the least at the poles; thus the reason for the difference in temperature

B/c cold air tends to sink this polar air wants to move toward the equator, this action forms major wind belts across the world

Local and Global Winds 22­3.notebook November 28, 2016

Types of Global Winds the doldrums­windless zone at the equator; also called the

intertropical convergence zone (ITCZ)

the trade winds­30o north or south of the equatoro trade wind from the north and south come together

near the equator in an area called the intertropical convergence zone (ITCZ)

o flow from the northeast to the southwesto sky is usually clear and has steady winds

the prevailing westerlies­between 30o and 60o north or south of the equator;

o responsible for much of the weather; o winds blow from the west to the easto strong winds

Local and Global Winds 22­3.notebook November 28, 2016

Types of Global Winds the polar easterlies­between 60o and the poles;

o flow from the northeast to the southwesto weak winds

The wind patterns are mostly at the surface. There are also higher altitude winds. Jet Stream­narrow belts of wind located at the top of

the troposphere;o flows from west to easto occurs where major wind patterns meeto altitude 12 Km

Hadley cells­3 cell circulation model of convection currents (cells); helps drive winds

Local WindsLand and Sea BreezesSea breezes occur during hot, summer days because of the unequal heating rates of land and water. During the day, the land surface heats up faster than the water surface. Therefore, the air above the land is warmer than the air above the ocean. Warmer air is lighter than cooler air. As a result, warm air rises. Therefore, the warmer air over the land surface is rising. As the warm air over the land is rising, the cooler air over the ocean is flowing over the land surface to replace the rising warm air. This is the sea breeze.

The bottom image illustrates the land breeze that occurs at night. The land surface cools quicker than the water surface at night. Therefore, the warmer air over the ocean is buoyant and is rising. The denser cool air over the land is flowing offshore to replenish the buoyant warm air and is called a land breeze.

Local and Global Winds 22­3.notebook November 28, 2016

Mountain and Valley Breezes

Local Winds

Similar to the land and sea breeze in its cycle are the valley and mountain breezes. Valley breezes occur in the day because air along mountain slopes is heated more intensely than air at the same elevation over a valley floor. Rapid radiational heat loss in the evening reverses the process to produce a mountain breeze.