A Conservative High-Order Characteristic Discontinuous Galerkin Advection Scheme for MPAS-Ocean

Dave R Lee1, Mark R Petersen2, Rob Lowrie2, Todd D. Ringler1 and William Lipscomb2, (1)Los Alamos National Laboratory, Climate, Ocean and Sea-Ice Modelling, Los Alamos, NM, United States, (2)Los Alamos National Laboratory, Los Alamos, NM, United States
Abstract:
A novel characteristic discontinuous Galerkin (CDG) scheme is discussed for the conservative advection of tracers on an unstructured mesh. The tracers are represented by arbitrarily high order basis functions within each cell, which along with the cell vertices are themselves advected along flow characteristics in order to integrate the swept volume of flux across a cell edge. These swept volumes are common for all tracers, and so there is little computational overhead required to apply the CDG scheme to additional tracers. The scheme is being developed for the MPAS-Ocean model, with the aim that it ultimately be deployed within the other MPAS cores (Sea-Ice, Land-Ice and Atmosphere). Preliminary results will be presented detailing how the errors and performance scale with resolution and the number of tracers respectively. These will be shown in the contexts of a 2D Cartesian plane and an unstructured grid of pentagons and hexagons on the sphere.
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