A Time Splitting Semi-Implicit Scheme for Atmospheric Modeling

In this study we present a finite-difference time-splitting semi-implicit scheme for modeling large- and meso-scale atmospheric dynamics. The semi-implicit approach includes an implicit time differencing of acoustic waves, which requires the solution of one-dimensional problems accomplished by using fast solvers and eliminates the most rigid restriction on the time step related to the propagation speed of acoustic waves. An additional splitting allows further increasing of the time step at a moderate price of the solution of a few two-dimensional problems. The constructed scheme is applied to forecasting the actual atmospheric fields and the obtained results are compared to those produced by the standard semi-implicit and explicit algorithms.