Application of the Semi-Lagrangian Inherently Conserving and Efficient (SLICE) Transport Method to Divergent Flows on a C Grid

Local conservation with the Semi-Lagrangian Inherently Conserving and Efficient (SLICE) transport method with a new trajectory algorithm is studied. Validation results of 1D and 2D passive advection with this new algorithm, which converges twice as fast as the old one, on the Arakawa C grid of a model in Cartesian coordinates are obtained. The effects of numerically computed divergence and trajectories on the results were also investigated. Random small-scale errors due to the divergence, especially with realistic winds, can be observed. The total mass is conserved, however, and is not affected since the results show clearly that SLICE ensures a perfect local conservation. This work represents the first step toward implementation of SLICE in the operational Canadian Global Environmental Multiscale (GEM) model.