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Center for Nonlinear Studies |
Semi-Lagrangian time-stepping schemes are now widely employed in operational numerical weather prediction models to circumvent the advective CFL restriction. The traditional approach is based on interpolation at the foot of a Lagrangian trajectory, implying a high computational cost in 3D. As noted by Boyd (2001), semi-Lagrangian schemes are equivalent to applying an integration factor (IF) and time-splitting the governing equations. Numerical experiments confirm that our choice of advecting velocity results in a second order scheme. We apply the IF scheme within the Canadian Mesoscale Compressible Community (MC2) limited area model and compare with interpolation using the Schaer et al 2D mountain wave idealized flow problem.
Host: Mikhail Shashkov