EXTINCTION COEFFICIENTS CALCULATED FROM AEROSOL SIZE DISTRIBUTIONS MEASURED IN A MARINE-ENVIRONMENT

The contributions by aerosols to the total extinction as measured by a Barnes transmissometer at San Nicolas Island were determined by subtracting the molecular contributions as calculated using LOWTRAN. These aerosol extinction coefficients are compared to those calculated using (a) aerosol size distributions measured at one end point of the transmissometer and airborne over the optical path, and (b) analytical models (LOWTRAN 3B maritime model and the Munn-Katz model which includes surface wind speed and relative humidity dependencies). The extinction coefficient variation with altitude calculated using the analytical models are compared with those calculated from measurements at sea of vertical aerosol size distributions.