Data from: Supersaturation and critical size of cloud condensation nuclei in marine stratus clouds

Observations of marine stratus clouds in clean air off the Californian
coast reveal a functional relationship between the number of cloud
condensation nuclei (CCN) and supersaturation. Satellite-derived liquid
droplet density estimates the number density of CCN. Combining the
estimated supersaturation using Kohler theory, global maps of
supersaturation and the critical activation size of CCN are estimated.
Here, we show that high supersaturation >0.5% persists over the
oceans with a critical CCN size of 25-30 nm, which is smaller than the
conventional wisdom of 60 nm. Independent support for such high
supersaturation in the marine cloud is obtained from CCN measurements
provided by the "Atmospheric Tomography Mission". Higher
supersaturation implies smaller activation size for CCN making cloud
formation more sensitive to changes in aerosol nucleation.