ECMWF Newsletter #173

New satellites

Florence Rabier. Director-General.Numerical weather prediction crucially depends on the Global Observing System, and in particular on satellites providing timely weather-related information across the globe. That is why ECMWF works closely with the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT) and the European Space Agency (ESA) to ensure that satellites will provide highly relevant information for weather prediction. In December, EUMETSAT will launch the first new geostationary satellite from the Meteosat Third Generation (MTG) series. This imager satellite, MTG-I1, will go into orbit at 36,000 km. It will provide more details about current weather conditions than Meteosat Second Generation (MSG) satellites, which will gradually be replaced by MTG. The MTG constellation comprises two imaging satellites and one sounding satellite. They complement a series of EUMETSAT polar-orbiting satellites, which circle the globe at an altitude of 817 km. A new series of such satellites, called EPS Second Generation, will be launched from the mid-2020s onwards with new and enhanced instruments.

While these satellites will provide much coverage, ECMWF uses data from a host of other satellites. A particularly interesting one was launched by ESA in 2018. The ground-breaking Aeolus satellite provides Doppler wind lidar observations. ECMWF started to assimilate observations from this pioneering ESA Earth Explorer Mission in January 2020. The aim of the mission was to demonstrate new spaced-based Doppler wind lidar capabilities. As the Aeolus article in this Newsletter shows, this aim has been fulfilled: statistically significant and good-magnitude positive impact on a number of forecasting parameters has been demonstrated. An operational follow-on mission is now being considered by ESA and EUMETSAT.

These developments come at a time when ECMWF switches its data centre operations from Reading (UK) to a new data centre in Bologna (Italy), which houses a new high-performance computing facility (HPCF). The ECMWF numerical weather prediction suite went into operations on the Atos HPCF on 18 October 2022. It will enable us to halve the grid spacing of our ensemble forecasts from 18 km to 9 km in an operational forecast upgrade planned for next year.

Other developments to be introduced in next year’s upgrade of the Integrated Forecasting System (IFS) are detailed in this Newsletter. They include a new way of computing semi-Lagrangian advection, and a completely new configuration for extended-range forecasts. The latter change also benefits from the new HPCF. It makes the grid spacing across the full time range of extended-range forecasts the same, it increases their frequency, and it includes twice as many ensemble members as before. The new configuration is supported by users, and that must be the ultimate test for any changes in suites and products we introduce at ECMWF.

Florence Rabier