The Dynamical Core Model Intercomparison Project (DCMIP-2016): Results of the Moist Baroclinic Wave Test Case

The 2016 Dynamical Core Model Intercomparison Project (DCMIP-2016) highlights the newest modeling techniques for global climate and weather models with particular focus on the newest non-hydrostatic global models, physics-dynamics coupling, and variable-resolution modeling. As part of a two-week summer school held in June 2016 at the National Center for Atmospheric Research (NCAR), a main objective of DCMIP-2016 was to establish an open-access database via the Earth System Grid Federation (ESGF) that hosts DCMIP-2016 simulations for community use from over 12 international modeling groups. The intercomparison is based on atmospheric model test cases of intermediate complexity that incorporate simplified physics parameterizations. The paper presents the results of the first DCMIP-2016 test case which is an idealized moist baroclinic wave. The wave is triggered by a localized perturbation that overlays an analytically-prescribed moist reference state in gradient-wind and hydrostatic balance. The simple moisture feedbacks are represented by a warm-rain Kessler-type parameterization without any cloud stage. As the wave develops over 10 days, this setup reveals the impact of the moisture processes on the development of the wave. The paper shows the characteristics of the test case and compares the results of the DCMIP-2016 models. This includes assessments of variable-resolution model configurations and the analysis of the coupling between the dynamics, physics and the tracer advection scheme. The latter is assessed as part of the baroclinic wave simulation via a "Terminator" tracer test that mimics photolysis-driven processes near the solar terminator. Overall, the paper highlights that idealized test cases are part of a model hierarchy that characterizes and informs the design of atmospheric dynamical cores.