absorption,reflectance and transmission

• Light reflection, absorption and transmission

  The 3 ways electromagnetic radiation from the sun can interact with the Earth's surface
• Remote Sensing Energy Mechanics

  1. Incident energy (Ei) strikes the Earth

  2. Reflected energy (Er)

  3. Absorbed energy (Ea)

  4. Transmitted energy (Et)
• Some electromagnetic energy (EM) freely passes through the atmosphere window before hitting the Earth's surface
• In remote sensing, light rays (incident energy) bounce off (reflected energy) objects back to the sensor in orbit
• Sensors detect the reflected energy
• Incident energy (Ei)

  The EM radiation that actually makes it to Earth
• Spectral reflectance (p)


  The proportion of reflected incident energy
• Incident energy interacts differently with different features on Earth
• Earth's features have different proportions of energy being reflected, absorbed, and transmitted
• Each object has its own spectral signature
• Spectral bands


  Ranges of wavelength ranges, e.g. infrared spectrum is from 750 nm to 1 mm, ultraviolet range is from 100 to 400 nm
• Multispectral images


  • Can have 3 to 10 bands
• Hyperspectral images


  • Have hundreds of finer bands