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.
Answer & explanation
Answer: (d) 1, 2 and 3
All three can be measured or estimated from satellite data: leaf greenness and chlorophyll from visible and near-infrared reflectance, land surface temperature from thermal infrared, and paddy methane by combining satellite-derived rice area and temperature with models.
- ✓ 1. Chlorophyll strongly absorbs visible light and leaves reflect near-infrared, so satellite vegetation indices (such as MODIS NDVI and EVI) track canopy greenness, which depends on leaf area, chlorophyll and canopy structure.
- ✓ 2. Methane from rice paddies has been estimated with a model driven by satellite-mapped rice area, land surface temperature and evapotranspiration, for example over China's Sanjiang Plain.
- ✓ 3. Land surface temperature is retrieved from thermal infrared measurements, for example the MODIS daily product at 1 km pixels.
Remember · Remote sensing gives vegetation greenness and chlorophyll (NDVI), land surface temperature (thermal infrared), and, with models, methane from rice fields.
Sources
- NASA MODIS: Vegetation Index Products (NDVI and EVI) ↗ “MODIS vegetation indices, produced on 16-day intervals and at multiple spatial resolutions, provide consistent spatial and temporal comparisons of vegetation canopy greenness, a composite property of leaf area, chlorophyll and canopy structure.”
- NASA MODIS: Land Surface Temperature and Emissivity (MOD11) ↗ “The Land Surface Temperature (LST) and Emissivity daily data are retrieved at 1km pixels by the generalized split-window algorithm and at 6km grids by the day/night algorithm.”
- Sun et al. (2017), PLoS ONE: satellite-data-based estimation of methane emissions from rice paddies, Sanjiang Plain, China (open-access copy on PubMed Central, NIH) ↗ “we estimated CH 4 emissions using a process-based model derived by rice area, CH 4 flux, land surface temperature (LST), and the ratio of precipitation (P) and evapotranspiration (ET) in rice paddies in the SJP”
Question and answer: UPSC's official GS Paper I (2019, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·