Limited Area Numerical Weather Forecasting on a Massively Parallel Computer

A data-parallel implementation on a SIMD platform of an operational numerical weather forecast model is presented. The performances of two popular numerical techniques within these models are discussed, namely finite difference (gridpoint) methods and spectral methods. In this paper in particular the performance achieved for a full production run is investigated. Also the price/performance ratios of several compute platforms for this forecast model are shown. 1 Introduction Numerical models of the atmosphere have much contributed to our general understanding of atmospheric processes. The use of such models has resulted in improved weather forecasts, with important economical impact; also these models are now being used as components in climate simulation models. The horizontal and vertical resolution of atmospheric models is an important factor determining the accuracy of the models. Present day computer power limits the number of gridpoints and thus the resolution to values that are ..