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?
Correct Answer: Option A
Explanation
1. The Westerlies are prevailing winds blowing from the west between roughly 30° and 60° latitude in both hemispheres.
2. Statement 1 is correct. The Southern Hemisphere between these latitudes is dominated by ocean, whereas the Northern Hemisphere has large continental landmasses (North America, Eurasia).
3. Landmasses exert greater frictional drag on winds and present topographical barriers (like mountain ranges) compared to relatively smooth ocean surfaces. This disrupts the flow, making the Westerlies in the Northern Hemisphere weaker and less persistent.
4. The vast expanse of ocean in the Southern Hemisphere allows the Westerlies to blow with greater strength and consistency, leading to terms like the "Roaring Forties".
5. Statement 2 is incorrect. The magnitude of the Coriolis force is primarily a function of latitude (zero at the equator, maximum at the poles) and the speed of the moving object (wind). It is not inherently higher in the Southern Hemisphere than the Northern Hemisphere at corresponding latitudes.
6. Thus, the difference in landmass distribution is the key reason for the observed difference in the strength and persistence of the Westerlies.
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