Sensitivity study formesoscale simulations of gravity waves above Antarctica during Vorcore

The observations from the Vorcore campaign (September 2005-January 2006) provide a unique dataset for the study of gravity waves in the lower stratosphere because of their wide coverage (150 000 observations from the South Pole to about 40°S) and of the quasi-Lagrangian nature of the superpressure balloons used. Numerical simulations with a mesoscale model are undertaken in order to investigate further the observed gravity waves, their sources and the induced momentum fluxes. The need for a high spatial resolutionmakes it necessary to find a compromise betweenthe size of themodel domainandthe lengthof the simulations. We describe preliminary simulations used to determine the best configuration of the model for this purpose, and show that the simulations compare reasonably well with the observations. Model results complement the observations and provide new insights into orographic and non-orographicwave sources.