Electromagnetic Spectrum and Atmospheric Windows MCQ with answer and solution

Concept

Thermal sensor requirements for urban heat island mapping

Formula

W = ε × σ × T⁴ (Stefan-Boltzmann Law)

Step-by-step solution

1. Surface temperature mapping relies fundamentally on radiant emission captured within thermal infrared atmospheric windows. 2. High spatial resolution resolves narrow urban features (individual buildings, road lanes, vegetation patches). 3. High radiometric resolution provides sensitive temperature quantization (small Noise Equivalent Temperature Difference) to detect fractional Kelvin variations. Answer: B

Explanation

Mapping micro-scale urban heat islands requires thermal infrared (TIR) sensors because surface kinetic temperature is deduced from radiant emission in the thermal spectrum (8 to 14 micrometers). Furthermore, resolving adjacent urban elements like asphalt roads versus green roofs requires high spatial resolution, while distinguishing subtle temperature variations requires high radiometric resolution (fine temperature sensitivity). Hence, option B is correct.

Why the other options are wrong

A) Microwave sensors lack high spatial resolution and radiometric sensitivity for urban street scale. C) Visible bands observe reflected light, unable to detect emitted surface thermal radiation. D) Near-infrared sensors map vegetation greenness, not kinetic temperature.

Shortcut

Urban Heat Island = Thermal IR (temperature) + High Spatial (fine features) + High Radiometric (subtle temp differences).

Common mistake

Choosing near-infrared or visible sensors, which capture reflected solar energy rather than emitted surface thermal radiation.