Wind can be described as the movement of air from the high-pressure area to the low-pressure area. There are many types of wind such as permanent, seasonal and local winds. A wind is named after the direction from which it blows, e.g. the wind blowing from the west is called westerly.
Forces Controlling Winds
Pressure Gradient and Winds
- There is a close relationship between the pressure and the wind speed.
- The greater the difference in air pressure between the two points, the steeper is the pressure gradient and greater is the speed of the wind.
- The gentler the pressure gradient slower is the speed of the wind.
The Coriolis Effect and Wind
- Winds do not cross the isobars at right angles as the pressure gradient directs them.
- They get deflected from their original paths.
- One of the most potent influences on wind direction is the deflection caused by the earth’s rotation on its axis.
- Demonstrated by Gaspaved de Coriolis in 1844 and known as the Coriolis effect or coriolis force.
- Coriolis force tend to deflect the winds from their original direction.
- In northern hemisphere winds are deflected towards their right, and in the southern hemisphere towards their left (see fig.) This is known as Ferrel’s law.
- The Coriolis force is absent along the equator but increases progressively towards the poles.
Wind Movement,Wind Movement
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