EGU2020-19344
https://doi.org/10.5194/egusphere-egu2020-19344
EGU General Assembly 2020
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Global simulations of the atmosphere at 1.45 km grid-spacing with the Integrated Forecasting System

Peter Düben1, Nils Wedi1, Sami Saarinen1, and Christian Zeman2
Peter Düben et al.
  • 1ECMWF, Research, Reading, United Kingdom of Great Britain and Northern Ireland (peter.dueben@ecmwf.int)
  • 2Eidgenössische Technische Hochschule Zürich

Global simulations with 1.45 km grid-spacing are presented that were performed with the Integrated Forecasting System (IFS) of the European Centre for Medium-Range Weather Forecasts (ECMWF). Simulations are uncoupled (without ocean, sea-ice or wave model), using 62 or 137 vertical levels and the full complexity of weather forecast simulations including recent date initial conditions, real-world topography, and state-of-the-art physical parametrizations and diabatic forcing including shallow convection, turbulent diffusion, radiation and five categories for the water substance (vapour, liquid, ice, rain, snow). Simulations are evaluated with regard to computational efficiency and model fidelity. Scaling results are presented that were performed on the fastest supercomputer in Europe - Piz Daint (Top 500, Nov 2018). Important choices for the model configuration at this unprecedented resolution for the IFS are discussed such as the use of hydrostatic and non-hydrostatic equations or the time resolution of physical phenomena which is defined by the length of the time step. 

Our simulations indicate that the IFS model — based on spectral transforms with a semi-implicit, semi-Lagrangian time-stepping scheme in contrast to more local discretization techniques — can provide a meaningful baseline reference for O(1) km global simulations.

How to cite: Düben, P., Wedi, N., Saarinen, S., and Zeman, C.: Global simulations of the atmosphere at 1.45 km grid-spacing with the Integrated Forecasting System, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-19344, https://doi.org/10.5194/egusphere-egu2020-19344, 2020

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