High resolution simulations of atmospheric and oceanic circulation

Abstract

The pursuit of fine spatial representation in models of the atmospheric and oceanic circulation has been a theme running through the development of the field of numerical simulation. For example, in studies of the global ocean circulation, a longstanding concern has been the issue of adequately resolving particularly energetic eddies, such as Gulf Stream rings. In global and regional atmospheric models, a key issue has been resolving mesoscale circulations that organize clouds and convection.With the recent advent of a new generation of high‐performance computing systems, such as the Japan Agency for Marine‐Earth Science and Technology's (JAMSTEC) Earth Simulator, some notable thresholds in terms of model resolution have been approached or, in some cases, surpassed. For example, the first long integrations with genuine eddy‐resolving global ocean models were reported in 2003. On the atmospheric side, decadal integrations with global models with effective horizontal resolution of approximately 20 kilometers have now become possible, and very short integrations of models that explicitly resolve scales approaching those of individual convective elements were first reported in 2005. These developments in global models have been paralleled by rising research activity with increasingly fine resolution regional atmospheric models for climate and shortrange forecasting applications.