Question

Planetary winds are of three types including ______.

• A. Trade winds
• B. Westerlies
• C. Polar winds
• D. All of these

Answer 1

The correct option is D All of these

1. Planetary Winds:

The winds blowing through­out the year from one latitude to another in response to latitudinal differences in air pressure are called “planetary or prevailing winds”. They involve large areas of the globe.

2. Trade Winds:

These are extremely steady winds blowing from subtropical high-pressure areas (30°N and S) towards the equatorial low-pressure belt. These winds should have blown from the north to south in Northern Hemisphere and south to north in Southern Hemisphere, but, they get deflected to the right in Northern Hemisphere and to the left in Southern Hemisphere due to Coriolis effect and Ferrel’s law. Thus, they blow as northeastern trades in Northern Hemisphere and southeastern trades in Southern Hemisphere.

They are also known as tropical easterlies, and they blow steadily in the same direction. They are noted for consistency in both force and direction.

3. The Westerlies:

These winds blow from subtropical high-pressure belts towards sub-polar low-pressure belts. The westerlies of Southern Hemi­sphere are stronger and constant in direction than Northern Hemisphere. These winds develop be­tween 40° and 65°S latitudes and these latitudes are known as Roaring Forties, Furious Fifties, and Shriek­ing Sixties.

Periodic Winds:

Periodic winds change their direction periodically with the change in season, e.g., Monsoons, Land and Sea Breezes, Mountain and Valley Breezes.

a. Monsoon Winds:

These winds are seasonal winds and refer to wind systems that have a pronounced, seasonal reversal of direction. According to ‘Flohn’, monsoon is a seasonal modification of general Planetary Wind System.