TY - JOUR T1 - Study of the relationship between the scattering angle and intensity of the atmospheric particles, reducing horizontal visibility TT - بررسی رابطه بین زاویه و شدت پراکندگی برای ذرات جوی کاهنده قابلیت دید افقی JF - opsi JO - opsi VL - 21 IS - 0 UR - http://opsi.ir/article-1-851-en.html Y1 - 2015 SP - 1397 EP - 1400 KW - horizontal visibility KW - atmospheric particles KW - atmospheric extinction coefficient KW - Mie scattering KW - forward scattering N2 - 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. M3 ER -