UPSC Physical Geography – Chapter 16: Global Climate Phenomena and Climate Change (21 MCQs)

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UPSC Physical Geography – Chapter 16: Global Climate Phenomena and Climate Change (21 MCQs) – 21 questions, subject: Geography. Every question has the correct answer with a one-line explanation; tap "Show Answer". Free practice for TNPSC, UPSC, SSC, Bank and RRB exams – Shanmugam IAS Academy, Coimbatore.

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1.  

During an El Niño, the sea surface off the coast of Peru becomes:

Correct Answer: B [warmer than normal]

Explanation:

Weakened trades let warm western Pacific water spread east, so the sea off Peru becomes warmer than normal.

2.  

According to NCERT, El Niño appears once every:

Correct Answer: D [three to seven years]

Explanation:

NCERT describes El Niño as a complex weather system that appears once every three to seven years.

3.  

The Southern Oscillation refers to changes in:

Correct Answer: C [sea-level pressure between the eastern and western tropical Pacific]

Explanation:

The Southern Oscillation is the see-saw of sea-level pressure between the eastern and western tropical Pacific, such as Tahiti and Darwin.

4.  

The Southern Oscillation was identified by:

Correct Answer: C [Gilbert Walker]

Explanation:

Gilbert Walker identified and named the Southern Oscillation in 1924 while searching for predictors of the Indian monsoon.

5.  

During La Niña, the trade winds over the Pacific:

Correct Answer: A [strengthen]

Explanation:

La Niña is marked by stronger-than-normal easterly trades that pile warm water in the west and strengthen upwelling off Peru.

6.  

A positive Indian Ocean Dipole means:

Correct Answer: B [the western Indian Ocean is warmer than the eastern]

Explanation:

In a positive IOD the western tropical Indian Ocean is warmer than the eastern part south of Indonesia.

7.  

The coastal fishery of Peru suffers in El Niño years mainly because:

Correct Answer: D [upwelling of nutrient-rich cold water weakens]

Explanation:

Warm surface water caps the coast and the upwelling of cold, nutrient-rich water weakens, so plankton and fish stocks fall.

8.  

A long, narrow band of concentrated water vapour that brings very heavy rain on reaching land is called a:

Correct Answer: B [atmospheric river]

Explanation:

Atmospheric rivers are long, narrow bands of concentrated water vapour in the lower atmosphere that bring very heavy rain or snow.

9.  

A heat dome is caused by:

Correct Answer: D [a persistent high-pressure ridge trapping hot air]

Explanation:

A persistent high-pressure ridge traps hot air, and the sinking air warms further, producing long heatwaves.

10.  

Consider the following statements:

1. The Madden–Julian Oscillation moves eastward along the tropics.
2. The polar vortex is a region of cold, low-pressure air around a pole.
3. The polar vortex is an ocean current.

Which of the statements given above is/are correct?

Correct Answer: B [1 and 2 only]

Explanation:

The MJO is an eastward-moving tropical pulse and the polar vortex is cold low-pressure air around a pole; statement 3 is false.

11.  

Assertion (A): A positive IOD can reduce the adverse effect of an El Niño on the Indian monsoon.

Reason (R): A warmer western Indian Ocean increases convection and moisture supply over India.

Correct Answer: A [Both A and R are true, and R is the correct explanation of A]

Explanation:

A warmer western Indian Ocean boosts convection and moisture supply to India, which offsets El Niño's drying, so R explains A.

12.  

Which of the following is NOT one of the Milankovitch cycles?

Correct Answer: D [Sunspot cycle]

Explanation:

sunspots are a solar cause.

13.  

Large volcanic eruptions tend to:

Correct Answer: A [cool the Earth for a year or two]

Explanation:

Large eruptions put sulphate aerosols into the stratosphere that reflect sunlight, cooling the Earth until they settle within a year or two.

14.  

The main cause of the present warming of the Earth is:

Correct Answer: B [increased greenhouse gases from human activity]

Explanation:

Rising carbon dioxide, methane and other greenhouse gases from human activity trap more long-wave radiation, driving present warming.

15.  

Evidence of past glacial advances and retreats is found in:

Correct Answer: C [moraines, glacial-lake sediments and tree rings]

Explanation:

Moraines and other glacial landforms, glacial-lake sediments and tree rings preserve records of past glacial advances and retreats.

16.  

The pressure see-saw of the Southern Oscillation is often measured between:

Correct Answer: D [Tahiti and Darwin]

Explanation:

Tahiti in the central-eastern Pacific and Darwin in northern Australia are the standard pair for the Southern Oscillation Index.

17.  

Arrange the following in chronological order:

1. Bjerknes links El Niño and the Southern Oscillation
2. Gilbert Walker names the Southern Oscillation
3. IPCC Sixth Assessment Report (Working Group I)
4. Indian Ocean Dipole described

Select the correct answer using the code given below:

Correct Answer: C [2-1-4-3]

Explanation:

1924, 1969, 1999, 2021.

18.  

In an El Niño year, Australia and Indonesia generally tend towards:

Correct Answer: A [drought]

Explanation:

In El Niño the rising air and rain shift east to the central Pacific, leaving Australia and Indonesia with sinking air and drought.

19.  

The Walker circulation is:

Correct Answer: C [an east–west loop of rising and sinking air along the equatorial Pacific]

Explanation:

The Walker circulation is the east–west loop of air rising over Indonesia and sinking over the cool eastern Pacific off Peru.

20.  

The main rainy season of south-eastern India, which studies link with ENSO and IOD, is the:

Correct Answer: D [north-east monsoon]

Explanation:

South-eastern India, including Tamil Nadu, gets most of its rain from the north-east monsoon in October–December.

21.  
UPSC Prelims 2014

Which of the following phenomena might have influenced the evolution of organisms?

1. Continental drift
2. Glacial cycles

Select the correct answer using the code given below:

Correct Answer: C [Both 1 and 2]

Explanation:

drift caused isolation and new climates; glacial cycles changed temperatures and habitats, driving adaptation.

➤ Full notes, maps, tables, a reason for every option and Mains PYQs – U08 · Physical Geography (UPSC book, ₹249): www.shanmugamiasacademy.in/study-materials/upsc-physical-geography

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