The uneven heating of the Earth by the sun results in the wind, which is the movement of air. It acts as the atmosphere’s great equaliser, moving heat, moisture, pollutants, and dust over vast distances. 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
A force is created by the difference in atmospheric pressure. The pressure gradient is the rate at which pressure varies with respect to distance. Where the isobars are close to one another, the pressure gradient is strong, and where they are far apart, it is weak. Strong pressure gradients result in higher wind speeds.
It has an impact on the wind’s velocity. It is most powerful at the surface and typically has an impact up to an elevation of one to three kilometres. Over the sea surface, there is little friction. As the frictional force increases, the wind’s velocity decreases.
The Coriolis force, which is produced by the earth’s rotation about its axis, influences the wind’s direction. The wind is deflected to the right in the northern hemisphere and to the left in the southern hemisphere by the Coriolis force. The Coriolis force is directly proportional to the angle of latitude, and the deflection is greater at high wind speeds. At the poles, it is greatest, and it is nonexistent at the equator.
The Coriolis force opposes the pressure gradient force in a perpendicular manner. The pressure gradient force runs perpendicular to an isobar, and the higher it is, the faster the wind is moving and the larger the deflection of the wind’s direction.
The winds are deflected from their true gradient course by the Coriolis force, which is produced by the rotation of the earth. According to this law, the winds turn toward their right in the Northern Hemisphere and to their left in the Southern Hemisphere.