QNH: a portable, parallel, multi-scale Quasi Non-Hydrostatic meteorological model

QNH is a Quasi Non-Hydrostatic meteorological model which has been 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 and 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 describe the QNH model and parallel code. We particularly focus on recent significant improvements in I/O performance made through use of a new I/O buffering process. We give performance results for the generation of a hurricane meteorological test case, on two massively parallel processors: the Intel Paragon and IBM SP2. 1 Introduction The Quasi Non-Hy..