PRESSURE GRADIENT- The change in Pressure measured across a given distance is called a “pressure gradient”.

The pressure gradient results in a net force called the “pressure gradient force”.

- The direction of pressure gradient is from high pressure to low pressure.
- Pressure gradient force is always perpendicular to the isobars.

- The pressure gradient force is responsible for triggering the initial horizontal movement of air called wind/advection.
- Pressure gradient force is always perpendicular to the isobars, thus wind movement is across/perpendicular to the isobars, wind makes acute angle against the isobar due to deflection by Coriolis force and rotation of earth. It is not exactly perpendicular to the isobars.
- PGF is stronger if isobars are closely placed and pressure changes more rapidly. Velocity of wind depends on magnitude on the magnitude of Pressure gradient, steeper/higher the pressure gradient higher is the velocity of the wind.

Pressure Gradient Force is expressed as force per unit volume, directed from high to low pressure:

PGF= Pressure change(mb)/distance(km)

Pressure gradient force, rotation of earth, Coriolis force, frictional force and centrifugal force affect the flow of wind on earth.

Menu

Menu