Vertical distributions of cloud condensation nuclei spectra over the summertime northeast Pacific and Atlantic Oceans

More than 80 hours of airborne cloud condensation nuclei (CCN) measurements made during the first phase of the First International Satellite Cloud Cli matology Project (ISCCP) Regional Experiment (FIRE 1) in the northeast Paci fic and the Atlantic Stratocumulus Transition Experiment (ASTEX) in the nor theast Atlantic are presented and analyzed. The complete CCN spectra from 0 .6% to 0.02% supersaturation and condensation nuclei concentrations are pre sented. Substantial direct continental/anthropogenic influence in ASTEX res ulted in an obvious division into maritime and continental components, whic h had 5 times higher concentrations. Boundary layer FIRE 1, ASTEX maritime, and previously published summertime Southern Ocean number concentration me asurements with the same instrument were comparable (110, 197, and 165 cm(- 3), respectively, at 0.6% supersaturation; 45, 60, and 48 cm(-3) at 0.1% su persaturation, and 18, 19, and 20 cm(-3) at 0.02% supersaturation).