Detailed Explanation:

Answer: Option 4 — 1, 2 and 3

Remote sensing technology uses satellite images to detect and monitor physical characteristics of areas by measuring reflected and emitted radiation. All three parameters mentioned can be effectively measured or estimated using satellite-based remote sensing data.

✅ Statement 1 – Correct: Chlorophyll content in vegetation is estimated by measuring light reflectance, as chlorophyll absorbs specific wavelengths for photosynthesis and the reflected light indicates chlorophyll concentration.

✅ Statement 2 – Correct: Greenhouse gas emissions from rice paddies can be estimated by detecting radiations emitted by methane and other gases, combined with thermal and spectral signatures of waterlogged conditions.

✅ Statement 3 – Correct: Land surface temperatures are directly measured by satellite sensors that detect infrared radiation emitted by the Earth's surface.

📝 Short Notes: Remote Sensing Applications

• Remote Sensing: The science of obtaining information about objects or areas from a distance, typically using satellites or aircraft-mounted sensors.
• Spectral Reflectance: Different surfaces and materials reflect electromagnetic radiation differently; vegetation reflects strongly in near-infrared while absorbing visible light for photosynthesis.
• Thermal Infrared Sensing: Used to measure land surface temperature by detecting heat radiation emitted from the Earth's surface.
• Agricultural Monitoring: Remote sensing helps monitor crop health, soil moisture, irrigation needs, and greenhouse gas emissions from agricultural activities.
• Vegetation Indices: NDVI (Normalized Difference Vegetation Index) and other indices derived from satellite data help assess vegetation vigor and chlorophyll content.
• Methane Detection: Advanced satellite sensors can detect methane emissions from rice paddies, wetlands, and other sources by measuring specific absorption bands in the infrared spectrum.