The authors studied on how many days per year Mistral and Tramontane occurred, both in climate simulation of the last century and in projection runs. Global and regional climate model simulations were investigated (e.g. by MPI-ESM and COSMO-CLM).
They found that climate simulations are able to reproduce the observed frequency of Mistral and Tramontane in the past. In the projection runs for a medium strong increase of greenhouse gas concentration (RCP 4.5), no significant changes in Mistral and Tramontane occurrence were seen. For a stronger increase of greenhouse gas concentration (RCP 8.5), some simulations showed a significant decrease in Tramontane days per year, but only small changes in Mistral days per year. Furthermore, the wind speeds in southern France during Mistral and Tramontane days are lower in RCP 8.5 simulations than in RCP 4.5 simulations.
The authors conclude that under future climate conditions a decrease of Tramontane days seems to be possible, while a change in Mistral days per year was not observed in the projections.
Obermann-Hellhund, A., D. Conte, S. Somot, C. Zsolt Torma, and B. Ahrens, 2017: Mistral and Tramontane wind systems in climate simulations from 1950 to 2100, Climate Dynamics, doi:10.1007/s00382-017-3635-8
Colleagues from Module C have investigated how the wind systems in southern France change under different climate scenarios.