An Energy Consistent Discretization of the Nonhydrostatic Equations in Primitive Variables

Journal of Advances in Modeling Earth Systems

Oksana Guba¹  Mark A. Taylor¹  Andrew Steyer¹  Paul A. Ullrich²  David M. Hall³  Christopher Eldred⁴ 

[1] Computational Science, Sandia National Laboratories Albuquerque NM USA;Department of Land, Air and Water Resources University of California Davis CA USA;NVIDIA Santa Clara CA USA;Université Grenoble Alpes, Inria, CNRS, Grenoble INP, LJK Grenoble France;

关键词: nonhydrostatic;    hamiltonian;    dynamical core;    energy conservation;    mimetic;   

DOI  :  10.1029/2019MS001783

来源: DOAJ

【 摘 要 】

Abstract We derive a formulation of the nonhydrostatic equations in spherical geometry with a Lorenz staggered vertical discretization. The combination conserves a discrete energy in exact time integration when coupled with a mimetic horizontal discretization. The formulation is a version of Dubos and Tort (2014, https://doi.org/10.1175/MWR-D-14-00069.1) rewritten in terms of primitive variables. It is valid for terrain following mass or height coordinates and for both Eulerian or vertically Lagrangian discretizations. The discretization relies on an extension to Simmons and Burridge (1981, https://doi.org/10.1175/1520-0493(1981)109<0758:AEAAMC>2.0.CO;2) vertical differencing, which we show obeys a discrete derivative product rule. This product rule allows us to simplify the treatment of the vertical transport terms. Energy conservation is obtained via a term‐by‐term balance in the kinetic, internal, and potential energy budgets, ensuring an energy‐consistent discretization up to time truncation error with no spurious sources of energy. We demonstrate convergence with respect to time truncation error in a spectral element code with a horizontal explicit vertically implicit implicit‐explicit time stepping algorithm.

【 授权许可】

Unknown