Numerical Approach on Effect of Topography to Severe Rainfall Using Non-Parameterized Cloud Microphysics Model

Abstract

The effect of topography to severe rainfall from cumulus, cumulonimbus is investigated numerically. To represent bottom topography in AE-type primitive model, we use σ-coordinate and tensor analysis. The Poisson equation translated into σ-coordinate has been solved numerically by using FFT and a iteration method. We obtain reasonable result from this method. Knowledge about effect of topography on severe rainfall is obtained from investigation of the numerical result. A couple of knowledge are:(a) Low topography functions as a trigger of cumulus but takes no effect on cumulus after it activated.(b) Downdraft and precipitation particle dropping caused by high topography prevent cumulus from developing.