Simulation results of unintentional aircraft-induced cloud clearing

The WRF model was used in conjunction with a relatively sophisticated bulk microphysical parameterization to simulate the effect of sudden ice nuclei injected into an entirely liquid cloud high in the atmosphere. The simulations mimic an actual event in which visual and satellite observations showed a liquid cloud at -31C that was penetrated by numerous aircraft leading to subsequent ice nucleation and eventual "cloud holes." The holes in the observed cloud persisted for many hours over a multi-state region in the southern U.S. Model-predicted rates of growth/decay of cloud holes were compared to satellite estimates. Using the model, we can also analyze the role of the Wegener–Bergeron–Findeisen process versus secondary circulations produced from the latest heat release. The idealized WRF experiment provides a simple yet effective framework to test a variety of ice nucleation processes with wide areas of application in planned or inadvertent weather modification.