Interactions between large structures, gravity waves and micro-turbulence – LASWATEX

In 2021, the Nobel Committee for Physics reminded that, in a context of global warming, the modern understanding of the variability of the Earth’s climate is based on the existence of clear separations of processes in terms of space and time scales, whose prediction requires interdisciplinary efforts. Fluid mechanics can therefore be an important contributor to the understanding of these fundamental questions, by providing answers about the interaction between large and small-scale structures in the atmosphere, and how their coupled interaction produces significant velocity and temperature fluctuations. In addition to this geostrophic turbulence, almost two-dimensional, that dominates large scales, gravity waves dominate smaller scale dynamics at mid-latitudes, and three-dimensional turbulent fields act at small scales and contribute strongly to vertical mixing and dissipation.
The current project is devoted to the understanding, prediction and modeling of large-scale/waves/micro-turbulence interaction phenomena which are characteristic of the atmosphere and of its variability. It relies on: (a) theoretical developments of transport equations of statistical moments of order up to 4, thus giving access to energy fluxes and extreme events in velocity-temperature fields; (b) high resolution direct numerical simulations providing detailed data of different interactions, in idealized conditions; (c) the atmospheric model WRF for predictions with realistic conditions but with a parameterization of small scales.
One important outcome of the project will be a model for accurate prediction of atmospheric variability phenomena, and the numerical database it will produce.