Solar radiation through the atmosphere — identify the incorrect statement As solar radiation traverses the atmosphere it may be scattered and absorbed. Which statement below is incorrect?
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Aremains unaffected
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Bgets scattered
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Cgets absorbed partially
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DNone of these
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EAll of these
Answer
Correct Answer: remains unaffected
Explanation
Introduction / Context:Before reaching sensors or the surface, solar radiation interacts with atmospheric molecules, aerosols, and clouds. Recognising these interactions is essential for atmospheric correction and accurate reflectance retrieval in remote sensing.
Given Data / Assumptions:
- Clear or hazy atmospheres introduce scattering and absorption.
- Wavelength dependence matters (e.g., Rayleigh ~ λ^-4).
- We assess qualitative correctness, not magnitudes.
Concept / Approach:Solar radiation is altered by scattering (Rayleigh, Mie, nonselective) and by selective absorption (e.g., ozone, water vapour). Therefore, a statement claiming it remains unaffected is incorrect.
Step-by-Step Reasoning:
1) Scattering redistributes energy angularly and spectrally.2) Absorption removes energy at specific bands (e.g., O3 in UV, H2O in NIR/SWIR).3) Net effect: irradiance at ground and at-sensor radiance differ from exo-atmospheric values.Verification / Alternative check:Blue sky colour and atmospheric windows (8–14 μm) are direct evidence of wavelength-dependent interaction.
Why Other Options Are Wrong:
- gets scattered: True in real atmospheres.
- gets absorbed partially: True in specific bands.
- None/All of these: Do not match the targeted incorrect statement.
Common Pitfalls:Ignoring aerosols and water vapour; assuming uniform transmittance across wavelengths.
Final Answer:remains unaffected