The E3SM Nonhydrostatic Dynamical Core Formulation
We derive an energy-consistent discretization of the nonhydrostatic equations for use in global models of the Earth’s atmosphere. The discretization is implemented in a new dynamical core for DOE’s Energy Exascale Earth System Model (E3SM).
This new dynamical core is being used in E3SM’s nonhydrostatic cloud-resolving modeling project. This project together with DOE’s upcoming Exascale supercomputers will allow us to resolve the convective processes responsible for storm systems, removing a large source of uncertainty in climate change projections.
Energy consistent discretizations have proven useful in guiding the development of numerical methods for simulating fluid dynamics. They ensure that the discrete method does not have any spurious sources of energy, which can lead to unstable and unrealistic simulations. Here we provide an energy consistent discretization of the equations used by global models of the Earth's atmosphere. The discretization is written in terms of standard variables in spherical coordinates and supports a wide variety of terrain-following vertical coordinates. It can be used with any horizontal discretization that has a discrete version of the integration-by-parts identity.