Up in the clouds

The facts and the project

Clouds represent the areas of greatest uncertainty for weather prediction models. Their exact properties are dependent on a multitude of interactions between air, water vapour, droplets and aerosols present in the atmosphere. The scales involved in all this, from the very smallest to the largest, and the complexity of the processes occurring, make it extremely difficult to access clouds by either simulation or experimental means.

The results

However, thanks to the power available with GENCI’s Curie supercomputer, direct numeric simulations, conducted in 2012 and 2013 by a team from the Observatoire de la Côte d’Azur, were able to cast light on the timescales for the formation of rain with the highlighting of the extreme fluctuations during the evaporation and condensation of droplets under the effect of the flow of air in the cloud. These results are going to help improve the parameterisation of clouds for weather models.


350 000 core hours on Curie (CEA/TGCC)

Principal Investigator: Jérémie Bec - Observatoire de la Côte d’azur