Visibility forecast in the phase of pre-condensation

Abstract

The effect on visibility of the swelling of aerosol particles due to increasing humidity is studied. The swelling can be described by r(f)/r (0) = (1 - f ) ?1/? where r ( f ) = particle radius at relative humidity f and ? = const ? 4 on the average. The visibility variation is expressed as V(f)/V(f 0 ) = [(1 - f )/(1 - f 0 )] V * ? 1)/? where V * = exponent of the aerosol size distribution ? 3 on the average. The last formula allows to compute the standard visual range V(f) at relative humidity f from the present standard visual range V(f 0 ) at present relative humidity f 0 . DOI: 10.1111/j.2153-3490.1969.tb00469.x