The presence of airborne particles in different climatic conditions can reduce visibility to zero and exert limitations on road, air and sea transportation systems. Visibility is a complex psycho-physical phenomenon, governed mainly by the atmospheric extinction coefficient associated with solid and liquid particles held in suspension in the atmosphere the extinction is caused primarily by scattering rather than by absorption of the light. Reviewing the phase dependence of Mie scattering function, we have estimated that the best angle to measure atmospheric extinction coefficient, and so weather condition, is 42 degrees in the forward direction.

Keywords: horizontal visibility, atmospheric particles, atmospheric extinction coefficient, Mie scattering, forward scattering

Full-Text [PDF 720 kb]   (4779 Downloads)