Semi-Lagrangian Advection of Stratospheric Ozone on a Yin–Yang Grid System

AbstractThe lack of formal mass conservation that is inherent to the standard semi-Lagrangian transport scheme represents a significant model limitation that needs to be addressed. The magnitude of this impact depends on the nature of the advected quantity and particularly on the strength of species spatiotemporal variability. In this study, this issue is examined in the context of two configurations of the Environment Canada Global Environmental Multiscale (GEM) model. The first configuration (GEM Lat–Lon) is based on a global latitude–longitude grid system with the Arakawa C grid in the horizontal. The second configuration (GEM Yin–Yang) uses the overset Yin–Yang grid, which is singularity free and has quasi-uniform resolution. Both model versions have been used for studying the mass conservation property of passive and nonpassive tracers such as stratospheric ozone using different shape-preserving schemes and a global mass fixer. Experiments with idealized tracers indicate that the implementation of a ...