Assertion (A) : Wind patterns are clockwise in the northern hemisphere and anticlockwise in the southern hemisphere. Reason (R) : The directions of wind patterns in the northern and the southern hemisphere are governed by the Coriolis effect.

Assertion (A) is false: large-scale wind circulations and cyclonic rotations are counter‑clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere, not the other way around [3]. Reason (R) is true: the Coriolis effect — an apparent deflection due to Earth’s rotation — causes moving air to be deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere; this deflection converts radial inflow toward lows into a rotational flow whose sense differs between hemispheres [1]. Thus R correctly states the governing mechanism, but A states the rotational senses incorrectly, so R does not validate A.

Sources

1. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 23: Pressure Systems and Wind System > Why Tropical Cyclones Do Not Form At The Equator? > p. 310
2. [3] https://education.nationalgeographic.org/resource/coriolis-effect-1/
3. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 23: Pressure Systems and Wind System > UPSC Prelims 2011] Which one of the following weather conditions is indicated by a sudden fall in barometer reading? > p. 308