The Grey Zone in Numerical Weather Prediction: how to properly represent atmospheric motion on the 1 to 10 km range of scales?

July 2025 - July 2030

Computer simulations of the atmosphere are the foundation of weather forecast and climate models. They work well for phenomena that cover large areas (such as cold fronts and hurricanes) and for very small-scale phenomena (the dispersion of pollutants within a 1 km radius, for example), but they encounter a barrier with intermediate-scale phenomena, between 1 and 10 km, known as the "grey zone". In this range, the models fail due to the chaotic behavior of the atmosphere, known as turbulence (the same kind felt by an airplane in the clouds, but which is also present near the ground). This project will investigate in depth the behavior of the atmosphere's "grey zone" using a suite of mathematical, statistical, and computational tools. The main objective is to increase the predictability of phenomena that occur on the 1 to 10 km scale.