The 2012 Dynamical Core Model Intercomparison Project (DCMIP)

The paper highlights results of the Dynamical Core Model Intercomparison Project (DCMIP) that has been held at the National Center for Atmospheric Research (NCAR) in August 2012. DCMIP paid special attention to future-generation non-hydrostatic global models. These will allow high-resolution km-scale simulations and provide a pathway for embedded variable-resolution meshes in regions of interest. The primary goals of DCMIP were to assess the scientific designs of over 18 current and forthcoming dynamical cores, to establish new non-hydrostatic and moist dynamical core test cases in the dynamical core community, to teach about 40 students how dynamical cores are built, and to introduce innovative cyberinfrastructure tools featured at http://earthsystemcog.org/projects/dcmip-2012/. The paper will present selected results of the DCMIP test suite. In particular, the dynamical cores will be intercompared in dry and moist configurations which include a gravity wave test on a reduced-size earth, the evolution of baroclinic waves and an idealized tropical cyclone test case that utilizes a simplified physics package. The results highlight the different characteristics of hydrostatic and non-hydrostatic simulations at small scales, reveal numerical artifacts such as grid imprinting, and showcase the increased spread in the model simulations when nonlinear moisture feedbacks are introduced. The ensemble spread allows estimates of the uncertainty of the model simulations.