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COSMO C++ Dynamical Core

MeteoSwiss and the Center of Climate Systems Modeling #

From Mai 2015 until December 2017 I was responsible for the COSMO C++ Dynamical core that powers the GPU-based weather model for MeteoSwiss, the Swiss National weather service and the Center for Climate Systems Modeling at ETH Zürich.

The weather predictions of the Swiss National weather service (MeteoSwiss) are powered by the COSMO weather model (as of December 2017).


The COSMO weather model powers the weather forecasts for multiple European countries. Organisations wishing to run the COSMO weather model need to be members or associated to the COSMO weather-modelling consortium. The COSMO weather model is a Fortran monolith that computes the forecast on a rectangular grid.

The COSMO model is super-seeded by the ICON weather model developed by DWD. In contrast to the COSMO weather model ICON works on equilateral grid.


At the center for Climate Systems Modeling I was responsible for porting and maintaining the C++ Dynamical Core of the COSMO Weather Model. The dynamical core is responsible to compute the fluid dynamics equations.

A computation step of the COSMO weather model

This work enabled the gpu-based COSMO-1, COSMO-E and COSMO-7 weather forecasts, a high-resolution forecast covering the Swiss alpine region.

Image showing the COSMO-1 compute domain.
COSMO-1 topography and compute domain

Operational Setup at MeteoSwiss #

I was directly involved in the operational setup and was able to gain a deep understanding how weather forecasting works.

For the PASC 2017 conference we published a poster describing the operational setup of the Swiss weather model:

PASC 2017 poster (pdf)

The PDF is available here and additional information can be found on the C2SM Wiki.

I am grateful for my then boss at MeteoSwiss Oliver Fuhrer for allowing me to create and publish this work.