Stratus cloud supersaturations



[1] A wide range of California coastal stratus cloud droplet concentrations (Nc) were compared with CCN spectra to provide numerous estimates of cloud supersaturations (S). These revealed the predicted decrease of S with higher CCN concentrations (NCCN). A significant result was frequent stratus cloud S significantly above 0.3%, especially for more maritime NCCN and Nc (i.e., <300 cm−3). This means that much smaller and more numerous particles than previously considered interact with the most important clouds for the indirect aerosol effect.