INTERCOMPARISON OF SPATIAL INTERPOLATION SCHEMES FOR USE IN NESTED GRID MODELS

Two geometrical and two advection-equivalent spatial interpolation sch emes were tested in providing lateral boundary conditions to a nested grid domain. Geometric interpolation schemes used in this study are a zeroth-order and a quadratic scheme, while the two advection-equivalen t interpolation schemes were based on upwind and Bott's advection sche mes. The test problem involves an initially cone-shaped distribution o f a scalar advected from a coarse to a fine grid. Simulation results w ere compared to the exact solution to study magnitude and phase charac teristics of each scheme. Results indicated that Bott's advection-equi valent interpolation scheme provided better interface conditions and, consequently, a more accurate transition of the signal from a coarse t o a fine grid.