Weather-dependent decisions are made on a daily basis in many sectors of the Swiss economy, not least in agriculture and the energy industry. Weather forecasts are also central to the operation of early warning systems for extreme weather events such as flooding, storms and hail. Numerical weather forecast models form the basis for weather forecasts and warnings produced by MeteoSwiss. They simulate the state of the atmosphere in the near future and produce probability forecasts for various parameters such as precipitation and temperature. These are then further processed into data products that can be employed in decision-making. To continuously improve the quality of these important functions, the forecast models must be developed on an ongoing basis.
MeteoSwiss currently produces its forecasts using two different ensemble configurations of the COSMO forecasting model (COSMO-1E and COSMO-2E). The model that is to succeed COSMO has been developed alongside ongoing operations over the past few years under the auspices of the German Meteorological Service (DWD) and the Max Planck Institute for Meteorology (MPI-M). Now that the strategic decision has been made by the COSMO consortium to replace COSMO with ICON, all further development of COSMO has been ended and the international developer community is refocusing its efforts on ICON. With the switch from COSMO to ICON, MeteoSwiss is hoping for an improvement in forecast quality and computer infrastructure, as well as synergy with ongoing research projects (GLORI-A, EXCLAIM).
The project: ICON-22
The goal of the project is to deploy ICON in the operational forecasting business of MeteoSwiss. The most important factor is that the new models, ICON-CH1-EPS and ICON-CH2-EPS, surpass (or at least equal) the existing COSMO-1E and COSMO-2E models in terms of quality, so that verification – in other words, the comparison of forecasts with measured data – generally produces better results. To achieve this, the existing ICON model must be adapted to the special needs and circumstances of Switzerland.
At the same time that the new model is introduced, an upgrade of the computing infrastructure at the Swiss National Supercomputing Centre at ETH Zurich (CSCS) will be carried out. This will enable ICON to operate on the new ALPS High-Performance Computing Platform in the CSCS, in so-called virtual clusters with a dedicated software environment.