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Interaction Between Radiation and the Material

Interaction Between Radiation and the Material. Prof. Arnon Karnieli The Remote Sensing Laboratory Jacob Blaustein Institute for Desert Research Ben-Gurion University of the Negev Sede-Boker Campus 84990, ISRAEL. Radiation Interaction with a Matter. Transmission.

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Interaction Between Radiation and the Material

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  1. Interaction Between Radiation and the Material Prof. Arnon Karnieli The Remote Sensing Laboratory Jacob Blaustein Institute for Desert Research Ben-Gurion University of the Negev Sede-Boker Campus 84990, ISRAEL

  2. Radiation Interaction with a Matter

  3. Transmission • Incident radiation passes through the material without attenuation • Change in the direction of radiation is given by the index of refraction of the material

  4. Refraction and Diffraction Transmitted waves are refracted or diffracted: Refraction occurs when an electromagnetic wave crosses a boundary from one medium to another. A wave entering a medium at an angle will change direction. Diffraction refers to the "bending of waves around an edge" of an object. Diffraction depends on the size of the object relative to the wavelength of the wave.

  5. Index of Refraction 1 2 Index of refraction (n) is the ratio of the speed of light in vacuum relative to the speed of light through the material Snell’s law describes refraction angles:

  6. Absorption - The material is opaque to incident radiation - A portion of EMR is converted to heat (re-radiated)

  7. Reflection Reflectance - Diffuse reflection (rough surface) - Specular reflectance (smooth surface)

  8. Scattering (DIFFUSE)

  9. Radiation Budget Equation

  10. Radiation Interaction with the Atmosphere

  11. Atmosphere Effect on Satellite Image With atmosphere No atmosphere

  12. Atmospheric Gases Nitrogen (N2) - 78%, Oxygen (O2) - 21%, Carbon Dioxide (CO2) - 0.03 %, plus other miscellaneous gases (e.g., H2O).

  13. Aerosol Types and Origin

  14. Atmospheric Absorption

  15. Atmospheric Absorption

  16. Atmospheric Windows and Shutters

  17. Scattering Vs. Absorption

  18. Rules - 1 Rules govern the interaction between energy and the atmospheric media: 1. Since there is an indirect relationship between the energy of the photon and the wavelength, less electronic influence on the atmospheric particles is expecting in long wavelengths. Ep= h*c/ 

  19. Rules - 2 2. The longer the wavelength, the lesser statistical probability for a contact between the radiation and the atmospheric particles.

  20. Scattering Scattering: random re-direction of the radiation ray from parallel orbit to to an omni-direction orbit.

  21. Scattering

  22. ScatteringTypes Scattering Types 1. Selective scattering - Rayleigh scattering - Mie scattering 2. Non-selective scattering

  23. Selective: Rayleigh Scattering Partical size <<  Type of particles: gases, atmospheric molecules Scattering intensity Mostly affects blue light

  24. AClear Blue Sky

  25. Red Sunsets

  26. Red Sunsets

  27. Far Landscape

  28. Skylight

  29. UV/Skylight Filter

  30. UV/Skylight Filter No Filter Skylight Filter

  31. Shadows on the Moon

  32. Black Sky

  33. Black Sky

  34. Selective: Mie Scattering to Partical size   Mean diameter 0.1 to 10m Type of particles: dust, smoke, soot, volcanic ash, water vapor, polen Scattering intensity Mostly affects red light

  35. Mie Scattering – Air Pollution Haifa, Israel, November 2004

  36. Mie Scattering – Biomass Burning

  37. Mie Scattering – Volcanic Eruption Mt. Pinatubo stratospheric Aerosol layer as seen from Space Shuttle STS-43 (August 1991). The stratospheric aerosol layer forming two distinct strata is clearly visible approximately 10 kilometers above the cloud tops.

  38. Mie Scattering – Dust Storm

  39. Mie Scattering – Haze Episode Stead, Nevada, April 28, 1998

  40. Nonselective Scattering Partical size >>  Type of particles: water droplets, crystal ice. Affects all wavelength equally Independent of wavelength 0

  41. Nonselective Scattering

  42. Scattering - Summary

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