New study: DYAMOND - Next Generation Climate Models
At a very basic level the main job of the climate system is to redistribute energy as the solar energy received from the sun is converted to thermal energy (or enthalpy) and radiated back to space. The efficiency of this process is what sets the global temperature. This redistribution, and its efficiency, depends on two major modes of enthalpy transport, one from the equator to the poles, the other from the surface to the atmosphere. Existing climate models are distinguished by their use of physical principles to represent the first mode of transport, as they resolve the circulation systems (extra-tropical storms) and ocean gyres, that are responsible for this task. Because of limitations in computer power they are not, however, able to explicitly represent the other — which is incidentally more important — mode of transport. This transport is instead treated semi-empirically, in ways that limit the application and fidelity of present-day models. Recently computing has advanced to the point where it is now possible to explicitly resolve and globally simulate this second mode of enthalpy transport, leading to much more physically based models. Because these models can represent all the ‘storms’ that are associated with major modes of enthalpy transport, they are called Global Storm Resolving Models.
MPI-M has been leading the development of Global Storm Resolving Models. To this end, together with the University of Tokyo (an early pioneer in their development and application) it organized the first ever intercomparison of such models, under the framework of the DYAMOND project. Nine models participated in the project, each simulating forty days and forty nights of the atmosphere’s and land-surfaces evolution starting from common initial conditions and prescribed ocean temperatures. The simulated period was chosen to coincide with an airborne field campaign (NARVAL2) also initiated and led by the MPI-M. For many models this was the first time they were ever run for such a long period and for such a realistic test, and the comparison allowed an evaluation of their ability to robustly represent features of the climate system that have proven to be road blocks for traditional climate models. This includes the representation of convective storms and clouds, and their response to solar forcing in the form of their diurnal cycle. In addition to demonstrating an ability to better represent many aspects of the climate system the simulations provide output on scales that are much more comparable to what is observed, greatly increasing the bandwidth to observations. This apparent realism is shown in the figure, where it is difficult to distinguish the satellite image from the ten models simulating the same time period.
The simulations performed as part of DYAMOND have additionally been used to outline the technical requirements necessary to bring this type of simulation capability to bear on the evolution of the climate system over decades, and as coupled to the ocean circulation. The simulations also provided a platform for new forms of workflow, which were explored through Hackathons — short and collective programming sessions involving groups of small teams working intensively together over a period of hours to days. DYAMOND is the first jewel to arise out of the Sapphire model development project at MPI-M, and the excitement of these new horizons is already giving coherence to diverse activities through the institute.
More information
Original publication
Stevens, B., Satoh, M., Auger, L., Biercamp, J., Bretherton, C., Chen, X., Dueben, P., Judt, F., Khairoutdinov, M., Klocke, D., Kodama, C., Kornblueh, L., Lin, S.-J., Putman, W., Shibuya, R., Neumann, P., Roeber , N., Vanniere, B., Vidale, P.-L., Wedi, N. & Zhou, L. (2019). DYAMOND: The DYnamics of the Atmospheric general circulation Modeled On Non-hydrostatic Domains. Progress in Earth and Planetary Science, Vol. 6: 61, doi:10.1186/s40645-019-0304-z
Contact:
Prof Dr Bjorn Stevens
Max Planck Institute for Meteorology
Phone: +49 (0) 40 41173 422 (Assistant Angela Gruber)
Email: bjorn.stevens@mpimet.mpg.de