Question

Which of the following names is given to the planetary winds blowing between the tropics
1. Monsoon
2. Polar winds
3. Westerlies
4. Trade winds

Answer 1

Correct Answer - Option 4 : Trade winds

The correct answer is Trade winds.

 

• The trade winds are those blowing from the sub-tropical high-pressure areas towards the equatorial low-pressure belt.
• Therefore, these are confined to a region between 30°N and 30°S throughout the earth’s surface.
• They flow as the north-eastern trades in the northern hemisphere and the south-eastern trades in the southern hemisphere.
• This deflection in their ideally expected north-south direction is explained on the basis of Coriolis force and Farrel’s law.
• Trade winds are descending and stable in areas of their origin (sub-tropical high-pressure belt), and as they reach the equator, they become humid and warmer after picking up moisture on their way.
• The trade winds from two hemispheres meet at the equator, and due to convergence they rise and cause heavy rainfall.
• The eastern parts of the trade winds associated with the cool ocean currents are drier and more stable than the western parts of the ocean.

  

• Westerlies
  • The westerlies are the winds blowing from the subtropical high-pressure belts towards the sub-polar low-pressure belts.
  • They blow from south­west to north-east in the northern hemisphere and north-west to south-east in the southern hemisphere.
  • The westerlies of the southern hemisphere are stronger and persistent due to the vast expanse of water, while those of the northern hemisphere are irregular because of uneven relief of vast land-masses.
  • The westerlies are best developed between 40° and 65°S latitudes.
  • These latitudes are often called Roaring Forties, Furious Fifties, and Shrieking Sixties – dreaded terms for sailors.
• Polar winds
  • The Polar easterlies are dry, cold prevailing winds blowing from north-east to south-west direction in Northern Hemisphere and south-east to the north-west in Southern Hemisphere.
  • They blow from the polar high-pressure areas of the sub-polar lows.
• Monsoon
  • Monsoon is a major wind system that seasonally reverses its direction—such as one that blows for approximately six months from the northeast and six months from the southwest.