Airborne measurements of the water droplet spectra n(r) (r is radius) (0.23 ≤ r ≤ 150 μm) were made at about 14 levels in stratus layers during May and August 1981, 130 km SW of San Diego. All May days were found to be associated with air masses approximating marine air; all August days, with air masses approximating continental air. One May day and one August day were selected to represent these approximate marine and continental air masses, respectively. Four parameters were calculated from 15 n (r) observed along each level extending 6.44 km and from the average n (r) over the entire run. These parameters are the number of droplets, the mean droplet radius, the cross-sectional area and the liquid water content. Profiles of the four parameters were constructed as a function of the distance from the cloud base, defined to be at the level where the liquid water content is 0.02 g m−3. The droplet spectra on the marine and continental air mass days differed primarily because n(r) on the continental... Abstract Airborne measurements of the water droplet spectra n(r) (r is radius) (0.23 ≤ r ≤ 150 μm) were made at about 14 levels in stratus layers during May and August 1981, 130 km SW of San Diego. All May days were found to be associated with air masses approximating marine air; all August days, with air masses approximating continental air. One May day and one August day were selected to represent these approximate marine and continental air masses, respectively. Four parameters were calculated from 15 n (r) observed along each level extending 6.44 km and from the average n (r) over the entire run. These parameters are the number of droplets, the mean droplet radius, the cross-sectional area and the liquid water content. Profiles of the four parameters were constructed as a function of the distance from the cloud base, defined to be at the level where the liquid water content is 0.02 g m−3. The droplet spectra on the marine and continental air mass days differed primarily because n(r) on the continental...