Previous Year Question

Due to the rotation of the Earth, moving air and water appear to undergo a deflection relative to the Earth's surface. This apparent effect is known as the Coriolis Force or Coriolis effect. Because of this effect, moving winds are deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

The Coriolis Force does not itself generate wind. Wind flow is mainly initiated by the pressure gradient; the Coriolis Force changes the direction of the moving air. Therefore, the combined action of pressure and the Coriolis effect is important in determining large-scale atmospheric circulation.

The Coriolis effect is approximately zero at the Equator and increases with increasing latitude. This is also why tropical cyclones generally do not develop immediately near the Equator and why their direction of rotation differs between the Northern and Southern Hemispheres.

Therefore, the deflection of winds towards the left in the Southern Hemisphere is caused by the Coriolis Force.