Vortices, waves, and energy cascades in atmospheric turbulence

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Atmospheric fluid mechanics spans a wide range of length scale, from planetary scales down to millimetre scales. The mesoscale is an intermediate range of scales from kilometres to hundreds of kilometres; it supports an amazing variety of phenomena, including vortices, gravity waves, convective storms, and turbulence. Mesoscale dynamics play a key role in the energy budget of the atmosphere. Kinetic energy is primarily stored in large-scale vortices, and dissipated by very small-scale vortices; to reach the dissipation scales, energy must pass through the mesoscale. The transfers of energy between different scales in the mesoscale is called the mesoscale cascade. Despite its importance, this process is not completely understood and not fully captured by numerical weather prediction models. This research program aims to improve the representation of the mesoscale cascade in atmospheric models by gaining fundamental understanding of this process. There are three main objectives of this program: to understand the role of nonlinear waves and vortices in the mesoscale cascade; to quantify the exchanges of energy by different processes at different scales; and to improve the representation of small-scale turbulence in numerical models, especially localized upscale energy transfer. The work proposed here will deepen the fundamental understanding of atmospheric dynamics, improve the ability of numerical weather models to predict small-scale phenomena, and train students in atmosphere/ocean/climate dynamics and modelling, as well as for a variety of careers in computational modelling and data analysis.