Atmosphere Ocean Science Colloquium

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Parameterizing Convective Overshoot using Dedalus

Speaker: Daniel Lecoanet, Princeton

Location: Warren Weaver Hall 1302

Date: Wednesday, March 6, 2019, 3:30 p.m.

Synopsis:

There are many natural systems with convectively unstable fluid adjacent to stably stratified fluid: the Earth's atmosphere and ocean, as well as most stars, and perhaps even the Earth's liquid core. The convective motions penetrating into the stable region can enhance mixing, leading to changes in transport within the stable region. In this talk, I will describe the Dedalus code framework, which allows uses to solve nearly arbitrary PDEs using spectral methods, include the Boussinesq equations, anelastic equations, QG equations, etc. I will present convective overshoot simulations, in which I quantitatively measure the extra mixing due to overshooting motions. I parameterize the extra mixing as a spatially-dependent turbulent diffusivity. Finally, I will test the parameterization and interpret the results.