Wavefront coherence time seasonal variability and forecasting at the San Pedro Martir site

In order to efficiently use the recent astronomy high angular resolution te chniques (Adaptive Optics and Interferometry) to correct the perturbed wave front arriving at the telescope pupil, it is necessary to characterize a se t of astroclimatic parameters. One of these is the wavefront coherence time TAO It is an integral parameter, defining the maximum temporal correlation of the perturbed wavefront and it depends on the optical turbulence C-N(2) (x, y, z) and the wind intensity /V(z, y, z)/ in the whole troposphere. In this paper we use an atmospheric non-hydrostatic model (Meso-NH) conceived to simulate the classical meteorological parameters (p, T and V) and adapte d to simulate the optical turbulence (C-N(2)) to characterize the Tao in a region of some kilometers around ;he astronomical site of San Pedro Matir ( SPM) in Baja California (Mexico). We study the seasonal variability of the wind intensity in the whole atmosphere (20 km) above the SPM site during on e year. We show that, using the C-N(2) profiles simulated by Meso-Nh initia lized with ECMWF (European Center for Medium Weather Forecasts) data, we ob tain typical rao values in the V band (lambda = 0.5 mum) We calculate the s easonal variability of the tau (AO) in SPM and also some preliminary result s about the seasonal variability of C-N(2). Moreover, wr:suggest a physical explication of these variabilities. Finally we investigate the possibility of forecasting tau (AO) .