ABSTRACT
Winds are air masses in motion and the primary energy source behind this movement is the sun. The earth receives short wave radiation from the sun and the amount of energy so received is higher at the equator and lower latitudes than at poles and higher latitudes. Coriolis forces resulting from the rotation of earth, the moving air is deflected to its right side in the northern hemisphere. Friction has an important effect on the wind only in the first few kilometers of the Earth’s surface. Friction slows the movement of air. By slowing the movement of air, friction also reduces the Coriolis force, which is proportional to wind speed. The winds that change their direction periodically with the change in season are called secondary or periodic winds. It depends on monsoon, air masses and fronts, cyclones and anticyclones. Tertiary winds are generated by immediate influence of the surrounding terrain.
