The US Department of Energy (DOE) is developing a new global atmosphere model with 3 km horizontal grid spacing for the Energy Exascale Earth System Model (E3SM). By explicitly resolving an order of magnitude finer spatial scales than typical general circulation models, this new model provides an important tool for addressing a range of earth-system modeling questions, particularly related to the water cycle and its variability and change. This effort differs from other similar efforts by including a sophisticated higher-order closure scheme for subgrid-scale clouds and turbulence. This scheme will allow the model to better represent low clouds, which has been a deficiency of km-scale models in the past. The DOE effort is also set apart from other projects by being written in C++ and its use of the Kokkos library to enable performance on both conventional and emerging computer architectures. In this presentation, the strategy, motivation, and early results from this cutting-edge project will be introduced.

Prepared by LLNL under Contract DE-AC52-07NA27344. LLNL-ABS-780662