1 / 10

Light Scattering

Light Scattering. Rayleigh Scattering & Mie Scattering. What is Scattering?. Process by which particles suspended in a medium of a different index of refraction diffuse a portion of the incident radiation in all directions

jaden
Télécharger la présentation

Light Scattering

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Light Scattering Rayleigh Scattering & Mie Scattering

  2. What is Scattering? • Process by which particles suspended in a medium of a different index of refraction diffuse a portion of the incident radiation in all directions • No energy transformation results, only a change in the spatial distribution of the radiation • Function of ratio of particle diameter to wavelength of incident radiation

  3. Scattering Plane • Defined by the two rays involved, the source-particle ray and the particle-observer ray • Determined by observation, not fixed in space. For example, if the observer moves, the scattering plane will move with the observer.

  4. Rayleigh Scattering • Particles much smaller than wavelength of radiation • Proportional to 1/ λ4 • Shorter wavelengths scattered much more than longer wavelengths • Air molecules (N2 and O2) just the right size to very effectively scatter the shorter wavelengths (blue light) of incident solar radiation => blue sky

  5. Mie Scattering • Scattering by a isotropic, homogeneous sphere • Particle dimension comparable to wavelength of radiation (aerosols, water vapour) • Longer wavelengths scattered more than shorter wavelengths • More forward scattering • Scattering properties depend on wavelength, size, real and imaginary parts of refractive index, and size distribution

  6. Angle-Dependent Phase Function

  7. Phase Function Moments

  8. Discrete Ordinate Radiative Transfer Code: DISORT

  9. Theory • Fundamental Equation of RT • Phase Function Expansion • Can use addition theorem for spherical harmonics to expand P in Fourier cosine series over azimuthal angle

  10. Theory (Contd…) • Expand I in Fourier cosine series • RT equation transformed into 2M independent integro-differential equations • Integration performed by Gaussian quadrature (2N ‘streams’) • Reference: http://www.gps.caltech.edu/~vijay/Papers/RT_Models/DISORT%20Report.pdf

More Related