Convection-resolving climate modeling on future supercomputing platforms (crCLIM)
The crCLIM project aims to develop a European-scale convection-resolving climate modeling capability at a horizontal resolution of about 2 km using the next generation of supercomputing platforms.
Major uncertainties remain in our understanding of the processes that govern the water cycle in a changing climate and their representation in weather and climate models. Of particular concern are heavy precipitation events of convective origin (thunderstorms and rain showers).
The crCLIM project attempts to better represent these processes by developing a European-scale climate modeling capability at a horizontal resolution of about 2 km. This resolution is about 10 to 100 times higher than in conventional climate models. With such resolution, it becomes possible to explicitly represent relevant processes (for example the dynamics of deep convective and thunderstorm clouds) without using semi-empirical parameterizations. To achieve its goals, the project will exploit the next generation of high-performance computing architectures.
From a computer science perspective, this development poses major challenges. First, the need for increasing computer power requires the application of codes on emerging hardware architectures that includes heterogeneous many-core architectures consisting of both "traditional" central processing units (CPUs) and accelerators (e.g., GPUs). Second, with increasing computational resolution, the model output becomes unbearably voluminous, which requires new approaches to perform the analysis online rather than storing the model output.
The crCLIM project is highly interdisciplinary as it combines the expertise of climate and computational scientists. Ultimately, crCLIM will lead to a substantial reduction of some of the key uncertainties in the current generation of climate models, yield an improved representation of the water cycle including the drivers of extreme events (heavy precipitation events, floods, droughts, etc.), and enable more sophisticated climate change scenarios. This, in turn, will provide better guidance for impact assessment and climate change adaptation measures.
- ETH Research Group on Climate and Water Cycle, PI: Christoph Schär
- ETH Research Group on Atmospheric Dynamics, PI: Heini Wernli
- MeteoSwiss, PIs: Oliver Fuhrer, Philippe Steiner
- ETH Research Group on Scalable Parallel Computing Laboratory, PI: Torsten Hoefler
- Swiss National Super Computing Center, PI: Thomas Schulthess
The project crCLIM is organised in 4 subprojects which are all intimely connected. In addition, C2SM provides support for the COSMO model development and maintenance.
- Subproject A assesses how to efficiently exploit heterogeneous many-core computing architectures for weather and climate models. This involves addressing key questions such as the relative costs and benefits of higher-order numerical accuracy versus higher spatial resolution.
- Oliver Fuhrer (lead)
- Andrea Arteaga
- Christoph Charpilloz
- Torsten Höfler
- Thomas Schulthess
- Subproject B explores the virtualization of climate simulations from a computer science -perspective. It addresses the critical question of computational versus mass-storage loads, and develops an online analysis platform for high-resolution models.
- Torsten Höfler (lead)
- Salvatore Di Girolamo
- Thomas Schulthess
- Subproject C performs, validates and analyzes convection-resolving climate simulations over Europe.
- Christoph Schär (lead)
- Linda Schlemmer
- Nikolina Ban
- David Leutwyler
- Subproject D exploits the new level of virtualization using Eulerian and Lagrangian perspectives for the online analysis of synoptic features and water transport.
- Heini Wernli (lead)
- Michael Sprenger
- Nicolas Piaget
- Stefan Rüdisühli
- Leutwyler, D., O. Fuhrer, X. Lapillonne, D. Lüthi, C. Schär, 2015: Continental-Scale Climate Simulation at Kilometer-Resolution. ETH Zurich e-collection, DOI: http://dx.doi.org/10.3929/ethz-a-010483656 (short description and animation), online video on Vimeo.
- Leutwyler, D., O. Fuhrer, X. Lapillonne, D. Lüthi, C. Schär, 2015: Winter storm Kyrill in a Continental-Scale Convection-Resolving Climate Simulation. ETH Zurich e-collection, DOI: http://dx.doi.org/10.3929/ethz-a-010483662 (short description and animation), online video on Vimeo.
- Leutwyler, D., Fuhrer, O., Lapillonne, X., Lüthi, D., and Schär, C., 2016: Towards European-scale convection-resolving climate simulations with GPUs: a study with COSMO 4.19, Geosci. Model Dev., 9, 3393-3412, doi:10.5194/gmd-9-3393-2016.