UPSC Prelims Practice Questions — One-fourth of India’s monsoon rain evaporates mid-air, says new study

Question 1

The 2026 IITM study estimated raindrop evaporation from the stable isotope signature of rain and vapour. In this method, progressive enrichment of falling raindrops in heavy isotopes (such as ¹⁸O and ²H) is used chiefly as an indicator of which one of the following?

Accepted Answer

The fraction of raindrop mass lost to evaporation below the cloud base during descent

Answer

The altitude at which condensation first occurred inside the cloud

Answer

The sea-surface temperature of the oceanic moisture source

Answer

The electrical charge separation preceding lightning within the cloud

Question 2

India's first observational (isotope-based) estimate of monsoon raindrop evaporation over the northern Western Ghats was produced by which one of the following institutions?

Accepted Answer

Indian Institute of Tropical Meteorology (IITM), Pune

Answer

National Centre for Medium Range Weather Forecasting (NCMRWF), Noida

Answer

National Centre for Earth Science Studies (NCESS), Thiruvananthapuram

Answer

Indian National Centre for Ocean Information Services (INCOIS), Hyderabad

Question 3

In studies of sub-cloud raindrop evaporation, raindrops smaller than approximately which diameter are found to evaporate completely before falling about 700 m in typical conditions?

Accepted Answer

0.5 mm

Answer

1.5 mm

Answer

3 mm

Answer

5 mm

Question 4

Which one of the following best describes a 'sub-cloud process' as used in rainfall physics?

Accepted Answer

A process occurring below the cloud base, such as raindrop evaporation, that alters the rainfall amount reaching the surface and the isotopic composition of rain and vapour

Answer

The nucleation of ice crystals on aerosols within the upper reaches of a cumulonimbus cloud

Answer

The large-scale subsidence of dry air that suppresses cloud formation over a region

Answer

The condensation of water vapour into cloud droplets at the lifting condensation level

Question 5

How many autonomous institutes of the Ministry of Earth Sciences were merged into a single Society of the Ministry?

Accepted Answer

Five

Answer

Three

Answer

Seven

Answer

Ten

Question 6

Consider the following institutions:
1. Indian Institute of Tropical Meteorology, Pune
2. National Centre for Polar and Ocean Research, Goa
3. National Centre for Earth Science Studies, Thiruvananthapuram
4. National Institute of Oceanography, Goa
Which of the above are correctly identified as autonomous institutes under the Ministry of Earth Sciences?

Accepted Answer

1, 2 and 3

Answer

1 and 4 only

Answer

2, 3 and 4

Answer

1, 2, 3 and 4

Question 7

With respect to orographic rainfall over the Western Ghats during the monsoon, consider the following statements:
1. The windward (western) slopes receive very heavy rainfall as moist air is forced to rise.
2. Mahabaleshwar, on the crest, records among the highest seasonal rainfall totals in the region.
3. The leeward (eastern) side experiences a rain-shadow effect, producing a semi-arid belt.
4. The heavy rainfall of the northern Western Ghats is delivered mainly by the northeast (retreating) monsoon.
Which of the statements given above is/are NOT correct?

Accepted Answer

4 only

Answer

1 and 3

Answer

2 and 4

Answer

3 only

Question 8

Which one of the following is the primary agency responsible for monitoring and forecasting the southwest monsoon onset and the associated orographic rainfall over the Western Ghats?

Accepted Answer

India Meteorological Department (IMD)

Answer

Indian Institute of Tropical Meteorology (IITM)

Answer

National Centre for Medium Range Weather Forecasting (NCMRWF)

Answer

Indian National Centre for Ocean Information Services (INCOIS)

Question 9

Which one of the following is India's first Earth System Model developed to participate in the Coupled Model Intercomparison Project Phase 6 (CMIP6), contributing to the IPCC's Sixth Assessment Report?

Accepted Answer

IITM Earth System Model (IITM-ESM)

Answer

Climate Forecast System (NCEP-CFS)

Answer

Community Earth System Model (CESM)

Answer

Unified Model (UM) of the UK Met Office

Question 10

The IITM Earth System Model, used to generate India's regional climate projections for the South Asian monsoon, was developed under which centre of the Indian Institute of Tropical Meteorology, Pune?

Accepted Answer

Centre for Climate Change Research (CCCR)

Answer

National Centre for Seismology (NCS)

Answer

Centre for Marine Living Resources and Ecology (CMLRE)

Answer

National Centre for Coastal Research (NCCR)

Question 11

With reference to the 2026 IITM study on mid-air evaporation of monsoon rain, consider the following statements:
1. On average, about a quarter (~25%) of the monsoon rain mass evaporates before reaching the ground.
2. The daily evaporated fraction ranged from about 4% to 61%.
3. The study covered the southwest monsoon months of June to September.
4. The findings were published in the journal Nature Geoscience.
Which of the statements given above is/are NOT correct?

Accepted Answer

4 only

Answer

1 and 2

Answer

3 only

Answer

2 and 4

Question 12

The 'Three Years of Stable Water Isotope Data' dataset of daily rain samples from three geomorphic regions of India — Port Blair, Mahabaleshwar and Tezpur — was collected under the rainwater-isotope network of which institution?

Accepted Answer

Indian Institute of Tropical Meteorology (IITM), Pune

Answer

National Institute of Hydrology (NIH), Roorkee

Answer

Physical Research Laboratory (PRL), Ahmedabad

Answer

Central Water Commission (CWC), New Delhi

UPSC Prelims Practice Questions — One-fourth of India’s monsoon rain evaporates mid-air, says new study

Q1. The 2026 IITM study estimated raindrop evaporation from the stable isotope signature of rain and vapour. In this method, progressive enrichment of falling raindrops in heavy isotopes (such as ¹⁸O and ²H) is used chiefly as an indicator of which one of the following?

Q2. India's first observational (isotope-based) estimate of monsoon raindrop evaporation over the northern Western Ghats was produced by which one of the following institutions?

Q3. In studies of sub-cloud raindrop evaporation, raindrops smaller than approximately which diameter are found to evaporate completely before falling about 700 m in typical conditions?

Q4. Which one of the following best describes a 'sub-cloud process' as used in rainfall physics?

Q5. How many autonomous institutes of the Ministry of Earth Sciences were merged into a single Society of the Ministry?

Q8. Which one of the following is the primary agency responsible for monitoring and forecasting the southwest monsoon onset and the associated orographic rainfall over the Western Ghats?

Q9. Which one of the following is India's first Earth System Model developed to participate in the Coupled Model Intercomparison Project Phase 6 (CMIP6), contributing to the IPCC's Sixth Assessment Report?

Q10. The IITM Earth System Model, used to generate India's regional climate projections for the South Asian monsoon, was developed under which centre of the Indian Institute of Tropical Meteorology, Pune?

Q12. The 'Three Years of Stable Water Isotope Data' dataset of daily rain samples from three geomorphic regions of India — Port Blair, Mahabaleshwar and Tezpur — was collected under the rainwater-isotope network of which institution?