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Q32 (IAS/2019) Geography › World Physical Geography › Geospatial technology basics Official Key

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.

Result
Your answer: —  ·  Correct: D
Explanation

The correct answer is option D because satellite images and remote sensing data can be used for all three measurements. Research has established relationships between gross primary production, green LAI, and canopy chlorophyll content in crops, with implications for remote sensing of[2] primary production and synoptic monitoring of vegetation[1], confirming that chlorophyll content can be measured remotely (Statement 1). Remote sensing provides a synoptic picture of watersheds for characterisation of natural resources, land, water, vegetation and inter-relationship between them[4], demonstrating the capability to monitor agricultural areas like rice paddies for greenhouse gas estimation (Statement 2). The use of satellite in getting a continuous and synoptic view of larger area has made satellite communication vital, and satellite images can be used for weather forecast, monitoring of natural calamities, surveillance of border areas, etc.[5], which inherently includes land surface temperature measurements (Statement 3). Therefore, all three parameters—chlorophyll content, greenhouse gas emissions from rice paddies, and land surface temperatures—can be measured or estimated using satellite images and remote sensing data.

Sources
  1. [1] https://www.sciencedirect.com/science/article/abs/pii/S0034425716304722
  2. [2] https://www.sciencedirect.com/science/article/abs/pii/S0168192322003628
  3. [3] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 15: Regional Development and Planning > Principles of watershed management are: > p. 27
  4. [4] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 15: Regional Development and Planning > Principles of watershed management are: > p. 27
  5. [5] INDIA PEOPLE AND ECONOMY, TEXTBOOK IN GEOGRAPHY FOR CLASS XII (NCERT 2025 ed.) > Chapter 7: Transport and Communication > Satellite Communication > p. 84
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Don’t just practise – reverse-engineer the question. This panel shows where this PYQ came from (books / web), how the examiner broke it into hidden statements, and which nearby micro-concepts you were supposed to learn from it. Treat it like an autopsy of the question: what might have triggered it, which exact lines in the book matter, and what linked ideas you should carry forward to future questions.
Q. For the measurement/estimation of which of the following are satellite images/remote sensing data used? 1. Chlorophyll content in the ve…
At a glance
Origin: Books + Current Affairs Fairness: Moderate fairness Books / CA: 6.7/10 · 3.3/10

This is a classic 'Science & Tech Application' question disguised as Geography. It tests 'First Principles' rather than rote memory: if a phenomenon has a spectral signature (color, heat, or shape), a satellite can detect it. The key is understanding that satellites measure 'proxies' (e.g., greenness for chlorophyll, thermal IR for temperature) to estimate parameters.

How this question is built

This question can be broken into the following sub-statements. Tap a statement sentence to jump into its detailed analysis.

Statement 1
Can satellite images or remote sensing data be used to measure or estimate chlorophyll content in vegetation at a specific location?
Origin: Web / Current Affairs Fairness: CA heavy Web-answerable

Web source
Presence: 5/5
"* A.A. Gitelson _et al._ ### [Relationships between gross primary production, green LAI, and canopy chlorophyll content in maize: Implications for remote sensing of primary production](https://www.sciencedirect.com/science/article/pii/S0034425714000170) ### Remote Sens. Environ. (2014)"
Why this source?
  • Explicitly links canopy chlorophyll content in maize to remote sensing of primary production.
  • Indicates that chlorophyll content is a target variable for remote-sensing-based monitoring.
Web source
Presence: 5/5
"* A.A. Gitelson _et al._ ### Relationship between gross primary production and chlorophyll content in crops: Implications for the synoptic monitoring of vegetation"
Why this source?
  • References a work by Gitelson on the relationship between gross primary production and chlorophyll content with implications for synoptic (satellite-scale) monitoring.
  • Shows that chlorophyll content is considered in remote-sensing research literature.
Web source
Presence: 4/5
"* A.A. Gitelson _et al._ ### Relationship between gross primary production and chlorophyll content in crops: Implications for"
Why this source?
  • Cites the same Gitelson relationship between gross primary production and chlorophyll content, tying it to remote sensing monitoring.
  • Reinforces that chlorophyll content is used in studies supporting satellite remote sensing of vegetation function.

Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 13: Our Home: Earth, a Unique Life Sustaining Planet > Probe and ponder > p. 211
Strength: 5/5
“The image in the beginning page was taken by an Indian Space Research Organisation (ISRO) Earth Observation Satellite and made by combining nearly 3000 smaller images, like pieces of a mosaic. Although it looks beautiful, it's a false colour image, where scientists use different colours to show different types of information. These satellite images help us study plants on land and tiny organisms in the ocean, and can even detect things like ocean temperature, oil spills, and wind direction. In this chapter, we will uncover the unique conditions that make Earth the perfect home for living beings.”
Why relevant

States that satellite images (including false-colour composites) are used to study plants on land and show different types of information.

How to extend

A student could infer that different colours represent spectral responses of vegetation and, using known links between chlorophyll and spectral reflectance, explore whether specific bands/indexes correlate with chlorophyll.

Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 15: Regional Development and Planning > Principles of watershed management are: > p. 27
Strength: 4/5
“Comprehensive planning for water management starts with obtaining suitable maps through remote sensing techniques. Remote sensing provides a synoptic picture of the watershed for characterisation of natural resources, land, water, vegetation and inter-relationship between them. Besides mapping natural resources, satellite imagery can give the estimate of the area covered by major”
Why relevant

Says remote sensing provides a synoptic picture for characterisation of vegetation and mapping natural resources.

How to extend

From the idea that satellites characterise vegetation over areas, one could extend to using spectral measurements from those sensors to estimate vegetation properties like chlorophyll.

Indian Economy, Vivek Singh (7th ed. 2023-24) > Chapter 11: Agriculture - Part II > Smart Farming > p. 359
Strength: 4/5
“These robots can also be used in harvesting and lifting. Heavy farming vehicles can also be navigated from the comfort of homes through phone screens to perform tasks and GPS can track their positions at every time.• Drones equipped with sensors and cameras are used for imaging, mapping and surveying the farms. They can be remotely controlled or they can fly automatically through software-controlled flight plans in their embedded systems, working in coordination with sensors and GPS. From the drone data, insights can be drawn regarding crop health, irrigation, spraying, planting, soil and field, plant counting and yield prediction and much more.• IoT based remote sensing utilizes sensors placed along the farms like weather stations for gathering data which is transmitted to analytical tool for analysis.”
Why relevant

Notes drones and sensors provide data from which 'insights regarding crop health' can be drawn.

How to extend

If crop health can be inferred from spectral/imagery data at close range, a student could reason that similar remotely sensed spectral indicators from satellites might estimate biochemical measures such as chlorophyll.

Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 3: The Drainage System of India > SARASWATI-THE MYSTERY OF A LOST RIVER > p. 27
Strength: 4/5
“palaeochannels as a migratory river. Its initial course flowed close to the Aravalli ranges and the successive six stages took west and north-westerly shifts till it coincides with the dry bed of the Ghaggar River. The course of the Saraswati River in the states of Punjab, Haryana and Rajasthan is clearly highlighted in the LANDSAT imagery by the vegetation cover thriving on the rich residual loamy soil along its earlier course. The digital enhancement studies of IRS-1C data (1995), combined with RADAR imagery from European Remote Sensing Satellite ERS 1/2, identified subsurface features and recognised the palaeochannels beneath the sands of the Thar Desert.”
Why relevant

Describes LANDSAT and IRS data highlighting vegetation patterns (e.g., palaeochannels) using imagery and digital enhancement.

How to extend

Because multispectral satellite data reveal vegetation patterns, one might extend that spectral signals could be processed to estimate vegetation properties tied to chlorophyll concentration.

Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 13: Plant Diversity of India > Leaves: > p. 204
Strength: 4/5
“• They are the part of the tree that converts energy into food (sugar). • Leaves are the food factories of a tree. • They contain a very special substance called chlorophyll. It is chlorophyll that gives leaves their green colour. • Chlorophyll is an extremely important biomolecule, used in photosynthesis. Leaves use the sun's energy to convert carbon dioxide from the atmosphere and water from the soil into sugar and oxygen.”
Why relevant

Explains chlorophyll is the green pigment in leaves and central to photosynthesis (gives leaves their green colour).

How to extend

Knowing chlorophyll affects leaf colour/reflectance, a student could connect leaf reflectance in visible/near-IR bands (captured by remote sensors) to possible chlorophyll estimation.

Statement 2
Can satellite images or remote sensing data be used to measure or estimate greenhouse gas emissions (e.g., methane) from rice paddies at a specific location?
Origin: Direct from books Fairness: Straightforward Book-answerable
From standard books
Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 15: Regional Development and Planning > Principles of watershed management are: > p. 27
Presence: 4/5
“Comprehensive planning for water management starts with obtaining suitable maps through remote sensing techniques. Remote sensing provides a synoptic picture of the watershed for characterisation of natural resources, land, water, vegetation and inter-relationship between them. Besides mapping natural resources, satellite imagery can give the estimate of the area covered by major”
Why this source?
  • Explicitly states remote sensing provides a synoptic picture and can estimate area covered by major land classes
  • Area estimates from satellite imagery are a necessary input for location-specific emission calculations
Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 7: Climate Change > 2. greenhouse gases > p. 11
Presence: 4/5
“Methane is generated by organic processes, such as digestion and rotting in the absence of oxygen (anaerobic processes). About 50 per cent of the excess methane being produced comes from bacterial action in the intestinal tracts of livestock and from underwater bacteria in rice felds. Methane is now believed responsible for at least 12 per cent of the total atmospheric warming, complementing the warming caused by the build-up of CO2 and equaling about one-half the contribution of CFCs.• (iii) Chlorofuorocarbon (CFCs) and Global Warming: Chlorofuorocarbon gases are produced by large manufactured molecules (polymers) containing chlorine, fuorine, and carbon. Tese gases possess remarkable heat properties.”
Why this source?
  • Identifies rice fields as a significant source of methane emissions
  • Links the specific emission source (rice paddies) to the class of greenhouse gas (methane) referenced in the statement
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 24: Climate Change Organizations > 24.21; NATIONAL GREEN HOUSE GAS INVENTORIES PROGRAMME (NGGIP) > p. 341
Presence: 4/5
“The IPCC established the national greenhouse gas Inventories Programme (NGGIP) to provide methods for estimating national inventories r:f greenhouse gas emissions to, and removals from, the atmosphere. • The guidance produced by the NGGIP is used by countries that are Parties to the UN Framework Convention on Climate Change (UNFCCC) to estimate the emissions and removals that they report to the UNFCCC. • It may be used by others who want to produce estimates consistent with national totals. Internationally agreed guidance is needed so that emission and removal estimates can be compared between countries and over time.”
Why this source?
  • Describes that IPCC/NGGIP provides methods for estimating greenhouse-gas inventories
  • Implies standardized approaches exist to convert activity data (e.g., area under rice) into emission estimates
Statement 3
Can satellite images or remote sensing data be used to measure or estimate land surface temperature at a specific location?
Origin: Direct from books Fairness: Straightforward Book-answerable
From standard books
INDIA PEOPLE AND ECONOMY, TEXTBOOK IN GEOGRAPHY FOR CLASS XII (NCERT 2025 ed.) > Chapter 7: Transport and Communication > Satellite Communication > p. 84
Presence: 5/5
“Satellites are mode of communication in themselves as well as they regulate the use of other means of communication. However, use of satellite in getting a continuous and synoptic view of larger area has made satellite communication very vital for the country due to the economic and strategic reasons. Satellite images can be used for the weather forecast, monitoring of natural calamities, surveillance of border areas, etc. On the basis of configuration and purposes, satellite system in India can be grouped into two: Indian National Satellite System (INSAT) and Indian Remote Sensing Satellite System (IRS). The INSAT, which was established in 1983,is a multi-purpose satellite system for telecommunication, meteorological observation and for various other data and programmes.”
Why this source?
  • Explicitly states satellite images are used for weather forecast and meteorological observation.
  • Names Indian satellite systems (INSAT, IRS) that perform meteorological observation and related data programs.
Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 15: Regional Development and Planning > Principles of watershed management are: > p. 27
Presence: 3/5
“Comprehensive planning for water management starts with obtaining suitable maps through remote sensing techniques. Remote sensing provides a synoptic picture of the watershed for characterisation of natural resources, land, water, vegetation and inter-relationship between them. Besides mapping natural resources, satellite imagery can give the estimate of the area covered by major”
Why this source?
  • Describes remote sensing as providing a synoptic picture for characterisation of land, water and vegetation.
  • States satellite imagery can give quantitative estimates (e.g., area covered), implying remote sensing yields measurable surface information.
FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 8: Solar Radiation, Heat Balance and Temperature > Distribution of Temperature > p. 71
Presence: 3/5
“shown on the map with the help of isotherms. The Isotherms are lines joining places having equal temperature. Figure 8.4 (a) and (b) show the distribution of surface air temperature in the month of January and July. In general the effect of the latitude on temperature is well pronounced on the map, as the isotherms are generally parallel to the latitude. The deviation from this general trend is more pronounced in January than in July, especially in the northern hemisphere. In the northern hemisphere the land surface area is much larger than in the southern hemisphere. Hence, the effects of land mass and the ocean currents are well pronounced.”
Why this source?
  • Explains that temperature distribution at places is mapped using isotherms (lines joining equal temperature).
  • Demonstrates that surface air temperature can be represented spatially on maps, supporting the idea of location-specific temperature estimation.
Pattern takeaway: UPSC Science & Tech questions often ask 'Can X technology do Y?'. If Y interacts with the physical world (light, heat, sound, waves) and X is a sensor for that interaction, the answer is almost always YES. Avoid over-analyzing 'specific location'—satellites are inherently geospatial tools.
How you should have studied
  1. [THE VERDICT]: Logical Sitter. Solvable using NCERT Geography basics (Isotherms, Remote Sensing) + Common Sense (Plants are green due to chlorophyll).
  2. [THE CONCEPTUAL TRIGGER]: Remote Sensing Applications & Space Technology (GS-3) > Electromagnetic Spectrum.
  3. [THE HORIZONTAL EXPANSION]: 1. **NDVI (Normalized Difference Vegetation Index)**: Uses Red & Near-Infrared bands to measure vegetation health. 2. **Thermal Infrared (TIR)**: Used to measure Land Surface Temperature (LST). 3. **Sentinel-5P**: Monitors atmospheric gases like Methane, NO2, and Ozone. 4. **SAR (Synthetic Aperture Radar)**: Can see through clouds/darkness (unlike optical sensors). 5. **GRACE Mission**: Measures groundwater depletion via gravity anomalies (non-optical).
  4. [THE STRATEGIC METACOGNITION]: Do not memorize lists of 'Uses of Satellites'. Instead, apply the 'Physics Check': Does the target object reflect light, emit heat, or change the gravity field? If yes, Remote Sensing applies. Chlorophyll reflects IR/Green; Temperature emits IR; Rice paddies have distinct spectral signatures.
Concept hooks from this question
📌 Adjacent topic to master
S1
👉 Remote sensing for vegetation mapping
💡 The insight

Remote sensing provides synoptic imagery used to characterise vegetation cover and estimate areas of different vegetation types.

High-yield for questions on land use, watershed management and environmental monitoring; links physical geography with resource planning and GIS-based policy tools. Mastering this helps answer questions on mapping, monitoring forest/vegetation cover and planning interventions.

📚 Reading List :
  • Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 15: Regional Development and Planning > Principles of watershed management are: > p. 27
  • Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 3: The Drainage System of India > SARASWATI-THE MYSTERY OF A LOST RIVER > p. 27
🔗 Anchor: "Can satellite images or remote sensing data be used to measure or estimate chlor..."
📌 Adjacent topic to master
S1
👉 False-colour satellite imagery and interpretation
💡 The insight

False-colour composites assign visible colours to selected wavelength bands to reveal plant-related information and other environmental variables.

Useful for deciphering remote sensing outputs in questions on crop monitoring, oceanographic and ecological studies; enables candidates to explain how spectral bands are used to highlight vegetation health and different land features.

📚 Reading List :
  • Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 13: Our Home: Earth, a Unique Life Sustaining Planet > Probe and ponder > p. 211
🔗 Anchor: "Can satellite images or remote sensing data be used to measure or estimate chlor..."
📌 Adjacent topic to master
S1
👉 Drone and sensor-based crop health assessment
💡 The insight

Drones and remote sensors capture high-resolution imagery and sensor data that provide insights into crop health and field-level monitoring.

Directly relevant for questions on smart farming, precision agriculture and crop insurance policy; connects technology, agricultural productivity and disaster response, allowing informed answers on modern agri-technology applications.

📚 Reading List :
  • Indian Economy, Vivek Singh (7th ed. 2023-24) > Chapter 10: Agriculture - Part I > Use of Technology for Crop insurance: > p. 322
  • Indian Economy, Vivek Singh (7th ed. 2023-24) > Chapter 11: Agriculture - Part II > Smart Farming > p. 359
🔗 Anchor: "Can satellite images or remote sensing data be used to measure or estimate chlor..."
📌 Adjacent topic to master
S2
👉 Remote sensing for land-use and area estimation
💡 The insight

Remote sensing provides synoptic maps and area estimates needed to quantify location-specific activity (e.g., extent of rice paddies).

High-yield for questions linking geospatial tools to environmental assessment; helps convert satellite outputs into activity data used in emissions calculations. Connects geography (land-use mapping), environment (sources of emissions), and technology (satellites).

📚 Reading List :
  • Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 15: Regional Development and Planning > Principles of watershed management are: > p. 27
  • Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 13: Our Home: Earth, a Unique Life Sustaining Planet > Probe and ponder > p. 211
  • INDIA PEOPLE AND ECONOMY, TEXTBOOK IN GEOGRAPHY FOR CLASS XII (NCERT 2025 ed.) > Chapter 7: Transport and Communication > Satellite Communication > p. 84
🔗 Anchor: "Can satellite images or remote sensing data be used to measure or estimate green..."
📌 Adjacent topic to master
S2
👉 Rice paddies as a methane source
💡 The insight

Rice fields are a known anthropogenic source of methane, the greenhouse gas exemplified in the statement.

Essential for answering environment questions on sectoral emissions and mitigation; links agricultural practices to climate change debates and inventory accounting. Enables questions on sector-specific mitigation policy and emission drivers.

📚 Reading List :
  • Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 7: Climate Change > 2. greenhouse gases > p. 11
  • Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 17: Climate Change > 17,3.3. Methane > p. 256
🔗 Anchor: "Can satellite images or remote sensing data be used to measure or estimate green..."
📌 Adjacent topic to master
S2
👉 Emission estimation frameworks (IPCC NGGIP)
💡 The insight

IPCC/NGGIP provides methods to convert activity data into greenhouse-gas emission estimates for inventories.

Crucial for policy and governance questions about national reporting and measurement methods; helps frame how remote-sensing-derived activity data can be integrated into standard estimation procedures. Useful for questions on international reporting obligations and methodological consistency.

📚 Reading List :
  • Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 24: Climate Change Organizations > 24.21; NATIONAL GREEN HOUSE GAS INVENTORIES PROGRAMME (NGGIP) > p. 341
🔗 Anchor: "Can satellite images or remote sensing data be used to measure or estimate green..."
📌 Adjacent topic to master
S3
👉 Satellites for meteorological observation
💡 The insight

Satellites (INSAT, IRS) are used for weather forecasting and meteorological observation, which underpins estimating surface parameters remotely.

High-yield for UPSC because understanding satellite roles links physical geography with technology and disaster management. It connects to topics on weather forecasting, remote sensing applications, and national satellite systems, enabling answers on how modern observations are obtained and used in planning.

📚 Reading List :
  • INDIA PEOPLE AND ECONOMY, TEXTBOOK IN GEOGRAPHY FOR CLASS XII (NCERT 2025 ed.) > Chapter 7: Transport and Communication > Satellite Communication > p. 84
🔗 Anchor: "Can satellite images or remote sensing data be used to measure or estimate land ..."
🌑 The Hidden Trap

Hyperspectral Imaging (HysIS). While standard satellites (Multispectral) see 'Green Vegetation' (Chlorophyll), Hyperspectral sensors break light into hundreds of narrow bands, allowing them to identify the *specific species* of the crop or specific *minerals* in the soil. This is the next logical question.

⚡ Elimination Cheat Code

The 'Proxy Principle'. A student might doubt Statement 2: 'How can a camera see gas emissions from mud?' Logic: Satellites measure the *Area* of rice paddies (visible) and *Methane Concentration* in the air column (spectroscopy). Combining these allows for 'Estimation'. If the question says 'Estimation', be liberal. If it said 'Direct Measurement of bacterial digestion', be skeptical.

🔗 Mains Connection

Precision Agriculture (GS-3). The three parameters in the question are the holy trinity of Smart Farming: Chlorophyll = Nitrogen/Fertilizer need; LST = Water stress/Irrigation need; Methane = Climate footprint. This data feeds into schemes like PM Fasal Bima Yojana for yield estimation.

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SIMILAR QUESTIONS

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NDA-II · 2009 · Q1 Relevance score: -7.23

Consider the following statements with respect to the Radar Imaging Satellite (RISAT-2): 1. This is the first Indian satellite with microwave imaging configuration on board. 2. The satellite will boost India’s defence capabilities. 3. It can take images of the earth day and night, even under rainy and cloudy-conditions. Which of the statements given above is/are correct?

CAPF · 2017 · Q101 Relevance score: -8.63

Which of the following statements about the Equatorial region are correct ? 1. It is a megathermal region 2. It is a sclerophyll region 3. It is a region of high development 4. It is a region of aerial streamlets Select the correct answer using the code given below :