High Resoution Modeling of the Apline Flows Using Anelastic Model EULAG

As computational capabilities of supercomputers continue to grow, resolution of mesoscale models for numerical weather prediction (NWP) systematically increases. Currently, spatial resolution of contemporary NWP models approaches 1km. Although higher resolution allows more adequately represent steep slopes of the terrain, it also involves necessity of employing more sophisticated numerical techniques for reliable and robust modeling of the flows over such complex terrain. For very high resolutions the models become also able to explicitly represent convective processes. In this context it is interesting to explore the models capability for representing influence of complicated orography on convection.

Here, we present the results of the very high resolution simulations of convection over south-western Alps for the regime of relatively weak external forcing. The focus of the study is on the inter-comparison of the simulations performed with 2.2, 1.1 and 0.55 km horizontal grids as well as comparison with observational data. The simulations have been performed using model EULAG. EULAG is a non-hydrostatic anelastic code developed in National Center for Atmospheric Research (NCAR) and is a prospective candidate for dynamical core of the future operational weather prediction model COSMO.