3D numerical simulations of optical turbulence at the Roque de Los Muchachos Observatory using the atmospherical model Meso-Nh

We show results obtained from simulations of the optical turbulence (OT), provided by the atmospheric non-hydrostatic Meso-Nh model applied to the astronomical site of Roque de Los Muchachos (RLM) in the Canary Islands. The validation of the numerical technique is done comparing simulated and measured $C_{\rm N}^2$ profiles obtained by different instruments operating during the same observation campaign of 11 nights. The results of this study show, for each night, a good average estimation of the OT obtained with Meso-Nh, compared to the dispersion of measurements from the different instruments. For the first time, the contribution to the optical turbulence of the radiation of the ground was studied. Quantitative estimations are given of the ability of the model to simulate the temperature near the ground around the telescope. Moreover, a set of 3D simulations shows that the horizontal distribution of the optical turbulence is not necessarily uniform, especially in the first 10 km above the ground. Finally, a study of the optimization of the optical turbulence parameterization in the model code is presented