Substitutability research for forward‐scatter meters in indoor low‐visibility environments

Visibility is a crucial parameter for aeronautical operations. Forward‐scatter meters are recommended to measure it because of inherent advantages. With wide use at airports, the substitutability among forward‐scatter meters is worth paying attention to, especially in low‐visibility environments. To confirm the substitutability among forward‐scatter meters, eight kinds of forward‐scatter meters were installed in an indoor atmospheric environment simulation chamber. The observed values of each of the eight forward‐scatter meters in haze and smoke low‐visibility environments were collected. By least‐squares fitting analysis and the ATE/LER zones method, in the haze, the two sets of CS125 can be substituted for each other in visibilities lower than 2000 m. PWD20 and V30 can be substituted for each other at visibilities lower than approximately 1200 m. From 1200 to 2000 m, the consistency of the two instruments is poor. In the smoke, CS125 and PWD20 display good substitutability with each other when visibility is less than 2000 m. If only focusing on visibilities less than approximately 1000 m, the VPF‐710 and V30 instruments can be substituted with each other. Eight kinds of forward‐scatter meters were installed in the indoor atmospheric environment simulation chamber. The continuous observations of each instrument in haze and smoke were obtained, respectively. The methodology uses least‐squares fitting analysis and the ATE/LER zones method to evaluate the substitutability between these instruments under two low‐visibility conditions.