Ice nucleation characteristics of an isolated wave cloud

This paper reports on a series of simulations of a single isolated gravity-wave cloud measured during the Interaction of Aerosol and Cold Clouds campaign. Using a parcel model with explicit liquid- and ice-phase microphysics, a number of different heterogeneous nucleation modes have been tested. It has been impossible for the model to reproduce, using any of the usual nucleation modes, both the observed peak ice number concentration and the ice water content, while not affecting the liquid-water part of the cloud. The key to simulating both of these simultaneously appears to lie in most ice nucleation occurring very rapidly at a critical time coincident with evaporation of the liquid droplets in the downdraught of the lee wave.