UPSC Prelims 2019 · Question 92 of 99

UPSC Prelims 2019 question on Remote Sensing Measurements

For the measurement/estimation of which of the following are satellite images/remote sensing data used?

1. Chlorophyll content in the vegetation of a specific location

2. Greenhouse gas emissions from rice paddies of a specific location

3. Land surface temperatures of a specific location

Select the correct answer using the code given below.

  1. 1 only
  2. 2 and 3 only
  3. 3 only
  4. 1, 2 and 3
Show answer

Answer: D. 1, 2 and 3

Verdict

All three are measured using satellite/remote sensing data → Option (d).

Analysis

Point 1 – CORRECT: Chlorophyll will reflect more light in the green and near infrared spectrum compared to other wavelengths. Near-infrared radiation is being used to detect healthy vegetation in agriculture. The global food supply is being monitored with satellite imagery and the Normalized Difference Vegetation Index (NDVI). Hence satellite images are used for chlorophyll content measurement.

Point 2 – CORRECT: Remote sensing from satellites can deliver information on GHG soil emissions by estimating tropospherical, near-surface CO2 and CH4 concentrations based on the measurement of the intensity of the reflected sunlight in small wavelength bands in the visible and short-wavelength IR portion of the spectrum. Hence satellite data is used for greenhouse gas emissions from rice paddies.

Point 3 – CORRECT: With the development of remote sensing from space, satellite data offers the possibility for measuring land surface temperature over the entire globe with sufficiently high temporal resolution and with complete spatially averaged rather than point values.

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