Air Motions

Geology 390WSUV

Dr. Robert M MacKay

1st Law (Law of Inertia)

Every object continues in its state of rest, or of uniform motion in a straight line, unless it is compelled to change that state by forces impressed upon it.

acceleration = 0.0 unless the objected is acted on by an unbalanced force

Forces that influence the wind

1. Pressure Gradient Force

2. Coriolis Force

3. Friction

On average Gravity nearly balances the vertical Pressure gradient(hydrostatic balance)

Fig. 8-16, p. 203

Pressure Gradient=∆P/dist

Pressure Gradient

Centrifugal force an (Apparent Force)

Centrifugal force an (Apparent Force)

Coriolis Force (apparent force due to Earth’s rotation)

Coriolis Force

Deflects air to right in NH& Left in SH

Is always zero at the equator

Increases with latitude

Increases with wind speed

Increases as planet rotation speed increase

Coriolis Force

Coriolis Force

Geostrophic Winds

Geostrophic Winds