The Impacts of Mesoscale Dynamics on Cirrus Structure Evaluated Using a High-Resolution Mesoscale Model

A thorough understanding of the dynamics of cirrus cloud formation is needed in order to parameterize these clouds accurately in numerical models. The scales at which cirrus clouds develop affect their treatment within the coarse resolution climate models, which typically have grid-point separations on The model used for this experiment is the non-hydrostatic verthe order of 200 km. There is a considerable amount of sion of the Pennsylvania State University/National Center for evidence to show that small-scale development is a factor in Atmospheric Research Mesoscale Model (PSU/NCAR MM5) cirrus formation. Observational studies have shown evidence (Dudhia 1993; Grell et al. 1994). A full atmospheric radiation of the development of cirrus convective elements on the package (Dudhia 1993) is incorporated, and the Reisner mesoscale (e.g., Sassen et al. 1989). Gultepe and Starr (1995) microphysical scheme (Reisner et al. 1997) is used with one documented from aircraft observations that waves of varying modification: the Meyers scheme (Meyers et al. 1992) wavelengths, ranging from 2 km to over 100 km, were present replaces the Fletcher’s average approach for ice nucleation. in the sampled cirrus clouds. For this reason, gravity waves The mixed-phase microphysical scheme implemented expliare the focus of this study. citly predicts ice, snow, cloud, and rain (Reisner et al. 1996).