1. Meteorology meets Astronomy : open discussion 1.Usefullness of atmospheric mesoscale modelling for astrophysical applications - to forecast astrophysical parameters (Opt.Turb.) for site operation scheduling - to provide high resolution 3D maps of atmospheric fields (Dx~1km,Dz~ 10 - 100m, Dt~ a few hours to several days) - to estimate the climatology of astrophysical parameters at specifc sites 2. Advance in atmospheric mesoscale modelling - Non Hydrostatic models with high resolution capacity and grid- nesting capacities (ex: WRF/MM5, Meso-NH…) nearly operational! - Progress in intialization and data assimilation at mesoscale - Operational products already exist : AMPS for Antarctica, Mauna Kea forecast center with WRF

2. 1.Needs expressed by astrophysics are very challenging for the meteorological community - To better represent turbulence (dynamics) and Cn² for conditions difficult for atmospheric modelling : e.g. stable layers : TKE calibration; complex terrain (lee waves, drainage flow, …) - To improve the modelling in the lowest layers and the surface processes : effect of soil, vegetation, turbulence in the Surface boundary layer - To better understand the link between the « optical outer scale » and the dynamical mixing length Meteorology meets Astronomy : open discussion

3. Other questions for meteorologists : Polar conditions : forecasting the height of the Boundary layer in Antarctica Transport of dust at some astrophysical sites : e.g. Las Palmas influenced by Sahara dusts : needs to have a synoptic approach and grid-nesting modelling, satellite data … Climate evolution at the TMT site for the next decades : IPCC data Usefullness of Large scale analysis (ECMWF, NCEP …) at the astronomical sites : e.g. high tropospheric characteristics Meteorology meets Astronomy : open discussion

4. Instrumentation : Common interest in instrumental technics : -Turbulence at low level from eddy correlation technics -Scintillometry : Estimation of sensible heat fluxes « horizontally » -Sodar : Wind speed and height of the Stable boundary layer Meteorology meets Astronomy : open discussion Intercomparison exercises needed ?: - R.Racine’s suggestion : A pilot experiment for intercomparison of simulated and observed astronomical parameters