Official Answer Key & Detailed Solution
Ready to check the official UPSC Answer Key?
Click any option above to test yourself under exam conditions, or reveal the explanation directly.
Correct Answer: Option (D) — 1, 2 and 3
Concept & Option Breakdown
Standard Reference VerifiedStatement 1 is correct: Multispectral and hyperspectral satellite sensors estimate chlorophyll concentration by measuring spectral reflectance in the visible and near-infrared bands (e.g., NDVI and red-edge indices).
Statement 2 is correct: Earth observation satellites equipped with atmospheric trace gas spectrometers and optical sensors measure agricultural inundation patterns and greenhouse gas concentrations (such as methane emissions from flooded paddy fields).
Statement 3 is correct: Thermal infrared (TIR) sensors on remote sensing satellites measure emitted radiance from the Earth's surface to derive accurate land surface temperature (LST) profiles for climate and urban heat island studies.
Remote sensing capabilities cover broad spectral bands: visible/NIR for chlorophyll, thermal infrared for surface temperatures, and atmospheric spectroscopy for GHGs.
Practice Full-Length & Sectional Prelims Mocks on this Interface
50 simulated tests in the APT Prelims Test Series (₹1,493) or 1-on-1 Mentorship with Avinash Sir.