DYNAMICO1.0, an icosahedral hydrostatic dynamical core designed for consistency and versatility
Abstract
The design of the icosahedral dynamical core DYNAMICO is presented. DYNAMICO solves the multilayer rotating shallowwater equations, a compressible variant of the same equivalent to a discretization of the hydrostatic primitive equations in a Lagrangian vertical coordinate, and the primitive equations in a hybrid massbased vertical coordinate. The common Hamiltonian structure of these sets of equations is exploited to formulate energyconserving spatial discretizations in a unified way.
The horizontal mesh is a quasiuniform icosahedral Cgrid obtained by subdivision of a regular icosahedron. Control volumes for mass, tracers and entropy/potential temperature are the hexagonal cells of the Voronoi mesh to avoid the fast numerical modes of the triangular Cgrid. The horizontal discretization is that of Ringler et al. (2010), whose discrete quasiHamiltonian structure is identified. The prognostic variables are arranged vertically on a Lorenz grid with all thermodynamical variables collocated with mass. The vertical discretization is obtained from the threedimensional Hamiltonian formulation. Tracers are transported using a secondorder finitevolume scheme with slope limiting for positivity. Explicit RungeKutta time integration is used for dynamics, and forwardintime integration with horizontal/vertical splitting is used for tracers. Most of the model code is common to the three sets of equations solved, making it easier to develop and validate each piece of the model separately.
Representative threedimensional test cases are run and analyzed, showing correctness of the model. The design permits to consider several extensions in the near future, from higherorder transport to more general dynamics, especially deepatmosphere and nonhydrostatic equations.
 Publication:

Geoscientific Model Development
 Pub Date:
 October 2015
 DOI:
 10.5194/gmd831312015
 Bibcode:
 2015GMD.....8.3131D