Real-time weather forecasting: QNH running on the Paragon

QNH is a Quasi Non-Hydrostatic meteorological model created by A. E. MacDonald and under development for three years at the NOAA Forecast Systems Laboratory. QNH is well-posed and therefore runs with a minimum of dissipation; it is applicable to all atmospheric scales, from the small scale to the planetary scale. Since QNH uses explicit finite difference approximations in all three spatial dimensions, it is readily amenable to massively parallel processing. We have written the code in such a way that it is portable and achieves high performance on a wide range of serial, vector and parallel computers. In this paper we give performances for QNH running on the Intel Paragon MPP in real-time. We particularly focus on gains made through use of a new I/O buffering process in the application space which allows overlap of physical I/O and computation. 1 Introduction The Quasi Non-Hydrostatic (QNH) meteorological model was created by A. E. MacDonald at the NOAA Forecast Systems Laboratory (FS..