What is wind and how do wind patterns form?

What is wind?

•Movement of air •caused by unequal heating of

earth’s atmosphere•results in movement of air due to a

type of energy transfer called convection

•Wind speed or velocity depends on the change in air pressure called the pressure gradient

• lines of equal pressure are called isobars

•where the lines are close together, the wind speed increases

•Winds will blow from high pressure to low pressure

Wind Speed

Air Pressure systems•High Pressure System: winds move clockwise and away the

center

• Low Pressure System: winds move counter clockwise and towards the center

H L

•These are the planetary winds-see ESRT•They are influenced by the earth’s

rotation-they are deflected to the right in the northern hemisphere and to the left in the southern hemisphere. This is known as the Coriolis Effect

•Winds originate in the opposite direction they move.

Prevailing Winds

•Currents of very fast moving winds high in the troposphere

•They influence the movement and development of storm systems

•see esrt

Jet Stream

Wrap up

•What causes wind?•How do winds move across the USA?•Where is it windy on a weather map?•How does the jet stream influence

weather patterns?•Why do winds curve?