Write a short note on wind.
Answers
Wind occurs because of horizontal and vertical differences (gradients) in atmospheric pressure. Accordingly, the distribution of winds is closely related to that of pressure. Near the Earth’s surface, winds generally flow around regions of relatively low and high pressure—cyclones and anticyclones, respectively. They rotate counterclockwise around lows in the Northern Hemisphere and clockwise around those in the Southern Hemisphere. Similarly, wind systems rotate around the centres of highs in the opposite direction. Wind speeds and gustiness are generally strongest by day when the heating of the ground by the Sun causes overturning of the air, the descending currents conserving the angular momentum of high-altitude winds. By night, the gustiness dies down and winds are generally lighter.