Question

Westerlies in southern hemisphere are stronger and persistent than in northern hemisphere. Why ?

1. Southern hemisphere has less landmass as compared to northern hemisphere.

2. Coriolis force is higher in southern hemisphere as compared to northern hemisphere.

Which of the statements given above is/are correct ?

(a) 1 only (b) 2 only (c) Both 1 and 2 (d) Neither 1 nor 2

Answer 1

(a) The higher speed and greater persistence of the westerlies in the Southern Hemisphere are caused by the difference in the atmospheric pressure patterns as well as its variation from that of the Northern hemisphere. The landmass in the southern hemisphere is comparatively less and average annual pressure decreases much more rapidly on the pole ward side of the high pressure belt. Statement 1 is correct. As far as coriolis force is concerned,it is strongest in the polar regions and zero at the equator. At the intermediate levels it varies directly as the sine of the latitude.