# SC²S Colloquium - January 29, 2018

Date: |
January 29, 2018 |

Room: |
02.07.023 |

Time: |

## Christopher Vogl: Investigation of Additive Runge-Kutta Methods for Atmospheric Dynamics in Earth System Models

A standard global atmospheric model is comprised of the Euler equations coupled with an equation of state that is a modified ideal gas law. This system of equations includes acoustic waves that must be simulated in a stable manner despite that their effect on atmospheric dynamics is usually negligible. Furthermore, this system is solved on computational grids that are typically more refined in the vertical direction to account for the shorter vertical length scales present in atmospheric physics. Implicit-Explicit schemes solve such a system by treating the stiff components with an implicit time integrator and the non-stiff components in an explicit manner, avoiding the usual costs of fully implicit methods. A class of such schemes, Additive Runge-Kutta methods, is investigated with the goal of easing the time-step restriction in Earth System Models.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344. Lawrence Livermore National Security, LLC