1. Consider the following statements :
1. In the tropical zone, the western sections of the oceans are warmer than the eastern sections owing to the influence of trade winds.
2. In the temperate zone, westerlies make the eastern sections of oceans warmer than the western sections.
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
[I.A.S. (Pre) 2021]
Ans. (c) Both 1 and 2
- In the tropics, the wind blows from east to west, making the ocean to the west of the landmass warmer.
- In the temperate zone, the wind blows from west to east, so the eastern side of the ocean gets warmer.
- Both of these statements are true.
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2. Assertion (A): Wind patterns are clockwise in the northern hemisphere and anti-clockwise in the southern hemisphere.
Reason (R): The directions of wind patterns in the northern and southern hemispheres are governed by the Coriolis effect.
Code :
(a) Both (A) and (R) are true, and (R) is the correct explanation of (A)
(b) Both (A) and (R) are true, but (R) is not the correct explanation of (A)
(c) (A) is true, but (R) is false
(d) (A) is false, but (R) is true
[I.A.S. (Pre) 2005]
Ans. (a) Both (A) and (R) are true, and (R) is the correct explanation of (A)
- Winds near the ground are affected by 3 forces –
- the pressure gradient force,
- Frictional Force
- the Coriolis force, which is named after G-G Coriolis.
- Due to the Earth’s rotation, the Coriolis force causes winds to turn right in the Northern Hemisphere and left in the Southern Hemisphere.
- This means that both the statement and its explanation are correct.
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3. Assertion (A): Wind patterns are clockwise in the southern hemisphere and anticlockwise in the northern hemisphere.
Reason (R): The directions of wind patterns in the northern and southern hemispheres are governed by the Coriolis effect.
Code :
(a) Both (A) and (R) are individually true, and (R) is the correct explanation of (A).
(b) Both (A) are (R) are individually true, but (R) is not the correct explanation of (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.
[M.P.P.C.S. (Pre) 2008]
Ans. (d) (A) is false, but (R) is true.
- The winds close to the ground are affected by three forces: pressure gradient force, friction, and the Coriolis force.
- This Coriolis force is named after the French physicist G-G Coriolis, and it makes the wind flow to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.
- Both statement A and the explanation of it, reason R, are true.
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4. Westerlies in the southern hemisphere are stronger and more persistent than in the northern hemisphere because?
1. The southern hemisphere has less landmass as compared to the northern hemisphere
2. Coriolis force is higher in the southern hemisphere as compared to the 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
[I.A.S. (Pre) 2011]
Ans. (a) 1 only
- The westerlies are prevailing wind from the west towards the east between the sub-tropical high-pressure zone (300 –350 ) and sub-polar low pressure (600 –650 ).
- These winds are more complicated in the northern hemisphere due to the larger expansion of land.
- These are less active during summer and more active in winter.
- As these pass over the sea, they carry moisture and cause rain.
- Due to the lesser expansion of land in the southern hemisphere, these winds become extremely powerful and turn into a storm.
- Due to its intensity in the southern hemisphere, it is called ‘Roaring Forties’ at 400 latitudes, ‘Furious Fifties’ at 500 latitudes, and ‘Shrieking Sixties’ at 600 latitudes.
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5. What are roaring forties, furious fifties, and shrieking sixties?
(a) Oceanic storms
(b) Westerlies in the Southern hemisphere
(c) Westerlies in the Northern hemisphere
(d) Pacific Ocean currents
[M.P.P.C.S. (Pre) 2015]
Ans. (b) Westerlies in the Southern hemisphere
- The westerlies are winds that blow from the west to the east in between the sub-tropical high-pressure zone and the sub-polar low-pressure zone.
- In the northern hemisphere, these winds are more complex because of the larger land area.
- They are weaker in the summer and stronger in the winter.
- This wind carries moisture as it passes over the sea, causing rain.
- In the southern hemisphere, the land area is smaller which causes the wind to become more powerful, creating storms.
- This intense wind is known as ‘Roaring Forties’ at 400 latitude, ‘Furious Fifties’ at 500 latitude, and ‘Shrieking Sixties’ at 600 latitude.
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6. Consider the following statements about the ‘Roaring Forties’:
1. They blow uninterrupted in the northern and southern hemispheres
2. They blow with great strength and constancy
3. Their direction is generally from north-west to east in the southern hemisphere
4. Overcast skies, rain, and raw weather are generally associated with them
Which of these statements are correct?
(a) 1, 2 and 3
(b) 2, 3 and 4
(c) 1, 3 and 4
(d) 1, 2 and 4
[I.A.S. (Pre) 2000]
Ans. (b) 2, 3 and 4
- The Roaring Forties are powerful winds that blow from west to east in the Southern Hemisphere, usually between 40° and 50° latitude.
- These winds are stormy and they are caused by air being pushed from the Equator towards the South Pole and the Earth’s rotation.
- This brings cloudy weather, rainfall, and cold temperatures so statements two, three, and four are correct.
- Wellington in New Zealand is the only capital city at the latitudes of the Roaring Forties.
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7. In which of the following regions long forties winds blow:
(a) North Sea
(b) Indian Ocean
(c) Caribbean Sea
(d) Corel Sea
[R.A.S./R.T.S. (Pre) 1993]
Ans. (b) Indian Ocean
- The Roaring Forties are strong winds that come from the west and blow in the Southern Hemisphere between the latitudes of 40° and 50°.
- These winds are stormy and caused by air being pushed from the Equator to the South Pole and the Earth’s rotation.
- They bring cloudy skies, rain, and cold temperatures, which makes statements 2, 3, and 4 true.
- The only capital city located in the Roaring Forties latitudes is Wellington, New Zealand.
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8. The term “Roaring Forties” refers to:
(a) Strong ocean winds between 40-60 degree south
(b) Strong tidal waves between 40-60 degree south
(c) The sailors heard a loud stormy voice between 40-60 degrees south
(d) Loud voices of volcanic eruptions between 40-60 degree south in the sea
[R.A.S./R.T.S. (Pre) 1993]
Ans. (a) Strong ocean winds between 40-60 degree south
- The Roaring Forties are powerful winds in the Southern Hemisphere between 40° and 50° latitude.
- They are caused by air being pushed from the Equator to the South Pole and the rotation of the Earth.
- The Roaring Forties often bring cloudy skies, rain, and cold temperatures.
- This means that statements two, three, and four are correct.
- Wellington in New Zealand is the only capital city that lies in the “Roaring Forties” latitudes.
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9. What is the effect of Chinook winds in the central plains in the USA?
(a) Temperature of winter rises
(b) The temperature of summer reduces
(c) Uniform temperature
(d) No effect on temperature
[Jharkhand P.C.S. (Pre) 2013]
Ans. (a) Temperature of winter rises
- Chinook winds are known as “snow-eaters” and usually blow during the winter and early spring in the Rocky Mountains, from Colorado in the US to British Columbia in Canada.
- These hot winds cause the temperature to rise quickly, melting the snow and making pastures available for grazing animals.
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10. What causes the wind to deflect toward the left in the southern hemisphere?
(a) Temperature
(b) Magnetic field
(c) Rotation of the earth
(d) Pressure
[I.A.S. (Pre) 2010]
Ans. (c) Rotation of the earth
- Winds are pushed in different directions in the northern and southern hemispheres because of the Coriolis force.
- This force is caused by the earth spinning on its axis.
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11. The winds flowing from a high-pressure area toward the Mediterranean Sea are-
(a) Westerly
(b) Trade wind
(c) Monsoonal wind
(d) Sea wind
[U.P.P.C.S. (Pre) 1992]
Ans. (b) Trade wind
- The Mediterranean Sea is found between 300 and 400 degrees latitude.
- This area is in a subtropical high-pressure area.
- In the summer, the trade winds blow from these latitudes to the northwest, while the westerly winds blow from these latitudes to the northeast in the winter.
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12. The seasonal reversal of winds is the typical characteristic of –
(a) Equatorial climate
(b) Mediterranean climate
(c) Monsoon climate
(d) All of the above climates
[I.A.S. (Pre) 2014]
Ans. (c) Monsoon climate
- Monsoons are seasonal winds that change direction depending on the season.
- In the summer, they blow from the ocean to the land, and in the winter, they blow from the land to the sea.
- According to Dr. Rama Shastry, monsoon winds move over a large area, and their direction changes with the season.
- Dr. H.G. Dubey says that the change in wind direction is what defines monsoon climate, so option (c) is correct.
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