Why is radar often used in remote sensing?
(Why are radio waves, visible light, and infrared radiation the most common forms of electromagnetic radiation sensed by Earth observing satellites?) The wavelengths of electromagnetic radiation most commonly used for remotely sensing Earth are: the spectrum of visible light, a wide spectrum of radio wavelengths, and several infrared wavelengths. A partial explanation of why these wavelengths are preferable is outlined below. When radar (which employs radio waves) is selected from these possible choices, the decision is usually based upon radar’s independence of solar illumination and weather conditions. See the questions: How does radar “see” at night? and How does radar “see” through clouds? for more details. There is a good reason why our eyes sense the electromagnetic radiation (light) they do: visible light represents a significant portion of the electromagnetic radiation which can pass through Earth’s atmosphere and ionosphere. A wide spectrum of radio waves, which radars employ,
