Mireille Bossy

Stochastic Lagrangian models for turbulent flows. Application to a downscaling method for wind forecast at small scales.

We propose a new downscaling method for the simulation of wind at small scales. Based on an existing numerical weather prediction model, we introduce a Langevin system as a local Lagrangian model aimed to estimate the distribution of the  wind at small scales. We borrow and adapt stochastic models proposed by Stephen B. Pope that have been widely used in the framework of multiphasic fluids.

After a brief description of the Pope models, we present our adaptation to the meteorological downscaling problem,  the associated numerical algorithm and some numerical results (joint work with F. Bernardin, C. Chauvin, P. Drobinski, A. Rousseau, T. Salameh) .

The last part of this talk will be devoted to the study of the well-posedness of a simplified Lagrangian model and its confined version in a spatial sub-domain which is used in the downscaling problem (joint work with J.F. Jabir).