P63  WRF Deep Horizontal and Vertical Nesting Applied to   Astronomical Conditions above Dome C in Antarctica

Giordano, C., J. Vernin, UniversitŽ de Nice-Sophia Antipolis, Observatoire de la C™te dÕAzur, CNRS-UMR7293, Lab. Lagrange, France.  A. Mahalov & M. Moustaoui, Center for Environmental Fluid Dynamics,  Arizona State University

We propose to present the first results obtained with WRF model in an astronomical context. The purpose of our study is to predict 24 hours ahead the optical conditions above an observatory to optimize the observation time, not only the meteorological conditions at ground level, but also the vertical distribution of the Òoptical turbulenceÓ and the wind speed, i.e the ÒseeingÓ. We chose to test the WRF model above Dome C, in Antarctica, where the astronomical conditions are very particular. Indeed during the summer, we can observe a steep and sudden improvement of the seeing when the sun is culminating above the horizon. It is interesting to test WRF above this site in order to retrieve this decrease. The seeing is computed using the Trinquet-Vernin model coupled with the vertical profiles of the wind shear and the potential temperature predicted by the WRF model. WRF is parametrized with its finest grid of 1km and 99 vertical levels with the vertical nesting. WRF first comparison with in situ seeing measurements made with a Differential Image Motion Monitor are very promising.