NUMERICAL EXPERIMENTS WITH HIGH-ORDER ADVECTIVE EQUATIONS.
NAVAL POSTGRADUATE SCHOOL MONTEREY CALIF
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Second-order and fourth-order two-dimensional advective equations developed by W. P. Crowley were examined to determine their applicability to atmospheric models. One second-order and two fourth-order forms were evaluated from their performances on a simple pattern advected by a linear, divergent velocity field. The same equations were substituted for the advection term of a simple barotropic forecast model to determine their performances on more general non-linear conditions. All forms of the equations remained stable in time and demonstrated the phase and amplitude characteristics predicted by Crowley. The fourth-order advection form gave best results. When substituted in the barotropic model, the fourth-order forms lead to improved trough and low-center movements, but RMSE was slightly larger than that resulting from second-order forms. The better RMSE of the lower order forms apparently resulted from their diffusive characteristics. Author
- Atmospheric Physics