The 0.125 degree finite‐volume general circulation model on the NASA Columbia supercomputer: Preliminary simulations of mesoscale vortices

Abstract

The NASA Columbia supercomputer was ranked second on the TOP500 List in November, 2004. Such a quantum jump in computing power provides unprecedented opportunities to conduct ultra‐high resolution simulations with the finite‐volume General Circulation Model (fvGCM). During 2004, the model was run in realtime experimentally at 0.25 degree resolution producing remarkable hurricane forecasts (Atlas et al., 2005). In 2005, the horizontal resolution was further doubled, which makes the fvGCM comparable to the first mesoscale resolving General Circulation Model at the Earth Simulator Center (Ohfuchi et al., 2004). Nine 5‐day 0.125 degree simulations of three hurricanes in 2004 are presented first for model validation. Then it is shown how the model can simulate the formation of the Catalina eddies and Hawaiian lee vortices, which are generated by the interaction of the synoptic‐scale flow with surface forcing, and have never been reproduced in a GCM before.

On numerical realizability of thermal convection

“…Global models with horizontal grid spacing D H % 10 km are already entering the realm of NWP [10,70], thus paving the way for equally intensive calculations at smaller scales. A D H % 10 km global simulation translates to a regional/mesoscale NWP with 20 times higher resolution D H $ 0:5 km.…”

Finite-volume transport on various cubed-sphere grids

“…The original FV core ( [1]; L04 hereafter) on the latitudinal-longitudinal grid is already an integral component within the National Aeronautics and Space Administration (NASA) Goddard Earth Observing System (GEOS) modeling suite (e.g. [2][3][4]), the climate modeling efforts at NOAA/GFDL [5], and the Community Atmosphere Model at the National Center for Atmospheric Research (NCAR) [6,7]. The main objectives of the cubed-sphere development are to avoid the numerical difficulties of the spherical poles, explore a new level of parallelism (two-dimensional X-Y domain decomposition) that is not practical within the current latitudelongitude grid construct [8], and to facilitate the development of a unified regional-global modeling system for both weather and climate applications.…”

“…The covariant and contra-variant wind vector components are presented in Eqs. (4) and (5) based on the local unit vectors ðe 1 ! ; e 2 !…”

A Multiscale Modeling System: Developments, Applications, and Critical Issues

“…The current Goddard MMF is about 5-10 times more than a 0.25° fvGCM and about the same as a 1/8° fvGCM (Shen et al 2006a). …”