Atmospheric Turbidity Analyzed by Means of Standardized Linke's Turbidity Factor

Abstract

The concept of standardized Linke's turbidity factor TLAM2 allows the conversion of the usual TL values, which exhibit virtual diurnal variations into new ones, which are strictly representative of the atmospheric turbidity caused by both water vapor and aerosol. The TLAM2 are TL values reduced at relative air mass 2 on the basis of a spectral TL model recently developed. The TLAM2 values are used to analyze the variations of atmospheric turbidity in a steep-sided urban alpine valley over a 3-year period. It appears that the dependence of the turbidity on altitude is related to the annual cycle of high and low turbidity periods. The TLAM2 concept is required to detect the instantaneous changes of atmospheric turbidity during the course of a given day, but it can also reveal the general trends in diurnal variations of turbidity, in relation to the season and to the altitude. Abstract The concept of standardized Linke's turbidity factor TLAM2 allows the conversion of the usual TL values, which exhibit virtual diurnal variations into new ones, which are strictly representative of the atmospheric turbidity caused by both water vapor and aerosol. The TLAM2 are TL values reduced at relative air mass 2 on the basis of a spectral TL model recently developed. The TLAM2 values are used to analyze the variations of atmospheric turbidity in a steep-sided urban alpine valley over a 3-year period. It appears that the dependence of the turbidity on altitude is related to the annual cycle of high and low turbidity periods. The TLAM2 concept is required to detect the instantaneous changes of atmospheric turbidity during the course of a given day, but it can also reveal the general trends in diurnal variations of turbidity, in relation to the season and to the altitude.