Application of split-explicit time integration scheme to a multi-level limited area model and forecast performance over Indian region

Abstract

An economical time integration scheme is of vital importance for NWP model being developed for operational use, as it is required to provide high quality forecasts by using the given computer within limited computing resources. Split-explicit time integration scheme discussed in this paper is near five times economical as compared to explicit scheme. In this scheme prognostic equations are splited according to the vertical modes in-to those governing the Rossby and gravity modes. £t enables lntegratl.on of the model at larger tjme step by incorporating suitable correctiol1 for gravity modes. The Limited Area Model (LAM) using this scheme dis-plays cons~rving properties of mass and energy. The scheme has inherent mechanism of smoothing high frequency waves.