CAMS upgrades its global forecasting system
19th May 2021 The global forecasting system of the Copernicus Atmosphere Monitoring Service (CAMS*) was successfully upgraded on 18 May. The CAMS forecasts are produced by the latest version of the highly successful Integrated Forecasting System (IFS), run by the European Centre for Medium-Range Weather Forecasts (ECMWF). The same IFS is used for ECMWF’s operational weather forecasts.
This upgrade combines one significant technical change with a limited set of scientific contributions:
The forecasts now use single-precision arithmetic for increased computational efficiency without compromising on quality. ‘Single precision’ forecasts have the advantage of being computationally less expensive than traditional ‘double precision’ forecasts. Such efficiency savings will greatly facilitate the introduction of higher resolution forecasts in future upgrades. Estimates of volcanic outgassing of sulphur dioxide from certain volcanoes has been reduced based on recent observations. A cap on anthropogenic primary organic matter emissions has been introduced to reduce forecasted atmospheric concentrations that were too high in the most polluted regions. The numerical precision of the prescribed emission fields has been increased to remove some artefacts. The new, improved global forecasting system has been running in test mode since January 2021 and yesterday it became the operational system. The CAMS validation team, led by the Dutch national weather service (Koninklijk Nederlands Meteorologisch Instituut, KNMI), carefully assessed the outputs to ensure the quality of the daily analyses and forecasts. The main findings of their extensive report are summarised in the table below, which identifies aspects of the forecasts that show an improvement compared to the previous global forecasting system, aspects that remain the same, and aspects that show some degradation.