Condensational growth of drops formed on giant sea-salt aerosol particles

As such, condensational growth of cloud drops is often assumed to be a well-understood process described by the drop growth equation. When this process is represented in models, CCN activate into cloud drops at cloud base, and it is often assumed that drops consist of pure water or that the hygroscopic contribution after drop activation is small because of the inclusion of only small CCN.

Drop growth rate in adiabatic ascent in such models is proportional to supersaturation and assumed to be inversely proportional to the drop radius, thereby making the drop spectrum narrow with altitude. However, the present study demonstrates that drop growth on giant sea-salt aerosol particles (GCCN; dry radius r(d) > 0.5 mu m) behaves differently. For typical marine stratocumulus updrafts and for drops grown on GCCN with sizes r(d) greater than or similar to 2 mu m, these drops typically remain concentrated salt solutions.