Thursday, May 20, 2021, 16:00
online only
(for the zoom link contact michael.spira@psi.ch, emanuele.bagnaschi@psi.ch or
pulak.banerjee@psi.ch)
Christoph Schär, ETHZ
Abstract:
Current global climate models operate at horizontal grid spacings of 50
to 200 km, and are thus unable to resolve key small-scale atmospheric
processes. Currently major efforts are underway toward refining the
horizontal resolution to about 1 km, using both global and regional
climate models (GCMs and RCMs). There is the well-founded hope that this
increase in resolution represents a quantum jump in climate modeling, as
it enables replacing the parameterizations of moist convection
(thunderstorms and rain showers) by explicit treatments. Recent results
suggest that the approach has a high potential to improving the
simulation of the water cycle and extreme events, and to reducing
uncertainties in climate change projections. Developing the approach on
global scales for extended climate simulations requires a concerted
effort. Key challenges include the exploitation of the next generation
hardware architecture using accelerators (e.g. graphics processing
units, GPUs), the development of new approaches to overcome the output
avalanche of future climate models, and the consistent maintenance of
models on a number of different compute architectures. Despite these
challenges, it will be argued that km-resolution GCMs, which are able to
run one simulated year per wall-clock day, might become available within
the current decade.
References and acknowledgements:
Ban, N., et al., 2021: The first multi-model ensemble of regional climate simulations at kilometer-scale resolution, Part I: Evaluation of precipitation. Clim. Dyn., published online, https://doi.org/10.1007/s00382-021-05708-w
Fuhrer O., T. Chadha, T. Hoefler, G. Kwasniewski, X. Lapillonne, D. Leutwyler, D. Lüthi, C. Osuna, C. Schär, T.C. Schulthess, H. Vogt, 2018. Near-global climate simulation at 1 km resolution: establishing a performance baseline on 4,888 GPUs with COSMO 5.0. Geosci. Model Develop., 11, 1665-1681, https://doi.org/10.5194/gmd-11-1665-2018
Heim, C., L. Hentgen, N. Ban, C. Schär, 2021: Inter-model Variability in Convection-resolving Simulations of Subtropical Marine Low Clouds. J. Meteorol. Soc. Japan, in revision
Hentgen, L., N. Ban, J. Vergara-Temprado, and C. Schär, 2021: Improving the simulation of tropical clouds in explicit highresolution climate models, submitted
Leutwyler, D. and C. Schär, 2019: Barotropic Instability of a Cyclone Core at Kilometer-Scale Resolution. J. Adv. Modeling Earth Syst., 11, 3390-3402, https://doi.org/10.1029/2019MS001847
Schär, C., O. Fuhrer, A. Arteaga, N. Ban, C. Charpilloz, S. Di Girolamo, L. Hentgen, T. Hoefler, X. Lapillonne, D. Leutwyler, K. Osterried, D. Panosetti, S. Rüdisühli, L. Schlemmer, T. Schulthess, M. Sprenger, S. Ubbiali, H. Wernli, 2020: Kilometer-scale climate models: Prospects and challenges. Bull. American Meteorol. Soc., 101 (5), E567-E587, https://doi.org/10.1175/BAMS-D-18-0167.1
Schulthess, T.P., P. Bauer, O. Fuhrer, T. Hoefler, C. Schär, N. Wedi, 2019: Reflecting on the goal and baseline for exascale computing: a roadmap based on weather and climate simulations. IEEE Computing in Science and Engineering, 21 (1), 30-41, https://doi.org/10.1109/MCSE.2018.2888788
Ubbiali, S., C. Schär, L. Schlemmer, and T. C. Schulthess, 2021: A numerical analysis of six physics-dynamics coupling schemes for atmospheric models. J. Advances Modeling Earth Systems, in revision
Vergara-Temprado, J., N. Ban, and C. Schär, 2021: Extreme sub-hourly precipitation intensities scale close to the Clausius- Clapeyron rate over Europe. Geophys. Res. Letters, 48, e2020GL089506. https://doi.org/10.1029/2020GL089506
Zeman, C., N. Wedi, P. Dueben, N. Ban, and C. Schär, 2021: Model
intercomparison of COSMO 5.0 and IFS 45r1 at kilometerscale
grid spacing. Geosci. Model Dev., revised version,
https://doi.org/10.5194/gmd-2021-31