Predicting global atmospheric ice nuclei distributions and their impacts on climate

Knowledge of cloud and precipitation formation processes remains incomplete, yet global precipitation is predominantly produced by clouds containing the ice phase. Ice first forms in clouds warmer than -36 degrees C on particles termed ice nuclei. We combine observations from field studies over a 14-year period, from a variety of locations around the globe, to show that the concentrations of ice nuclei active in mixed-phase cloud conditions can be related to temperature and the number concentrations of particles larger than 0.5 microm in diameter. This new relationship reduces unexplained variability in ice nuclei concentrations at a given temperature from approximately 10(3) to less than a factor of 10, with…