● The Factors affecting the velocity and Direction of Wind are:

1.             The pressure gradient force

2.             The frictional force

3.             The Coriolis forces

Pressure Gradient Force

●  The difference in atmospheric pressure produces a force. The rate of change of pressure with respect to distance is the pressure gradient.

●  The pressure gradient is strong where the isobars are close to each other and is weak where the isobars are apart.

●  If the pressure gradient is strong the velocity of wind is higher.

Frictional Force

●  It affects the speed of the wind. It is greatest at the surface and its influence generally extends up to an elevation of 1- 3 km.

●  Over the sea surface, the friction is minimal. The velocity of the wind decreases with the increase in frictional force.

Coriolis Force

●  The rotation of the earth about its axis creates Coriolis force that affects the direction of the wind.

●  This Coriolis force deflects the wind to the right direction in the northern hemisphere and to the left in the southern hemisphere.

●  The deflection is more when the wind velocity is high.

●  The Coriolis force is directly proportional to the angle of latitude. It is maximum at the poles and is absent at the equator.

●  The Coriolis force acts perpendicular to the pressure gradient force. The pressure gradient force is perpendicular to an isobar.

●  The higher the pressure gradient force, the more is the velocity of the wind and the larger is the deflection in the direction of the wind.

Ferrel’s Law

●  According to this law, the winds turn toward their right in the Northern Hemisphere and to their left in the Southern Hemisphere.

●  The winds are deflected from their true gradient course as a result of the Coriolis force which is generated by the rotation of the earth.