Research Report 2020 Research Report 2020 Table of contents Numerical weather prediction and data assimilation page 6 Process studies and modelling page 14 Climate page 20 Climate modelling Diagnostic, study and impacts Seasonal forecast Chemistry, aerosols and air quality page 30 Snow page 36 Oceanography page 40 Engineering, campaigns and observation products page 44 Observation engineering and products Campaigns Research and aeronautics page 52 Appendix page 54 Research occupies a special place within Météo-France, as it supports all of the establishment’s activities. It is the source of the progress that is then implemented in terms of observation and numerical weather and climate forecasting. It enables the Establishment to constantly improve the quality of its operational products and to open up new areas of work to meet the expectations of society and public authorities. A major element for any international Meteorological Service is the arrival at the end of 2020 of two new supercomputers which, since the very beginning of 2021, have offered an increase in power of a factor of 5.5. The forecasting suits have been installed there. The first major upgrade is under construction and will be tested These areas will be fed by a series of from mid-2021. It should be validated studies on the generalisation of ensemble -normally- at the beginning of 2022 and forecasting and its valorisation, on a new should bring significant progress in terms regional integrated system (“Earth system”) of global forecasts as well as forecasts for to go as far as the impacts, on a hectometric metropolitan France and the French overseas system for the sites at stake and on the territories. It should be noted that these two city, which brings together a number of new machines based on CPU processors are meteorological and climatic issues. There also equipped with a few GPU processors, will also be a commitment to participate which will enable new approaches to be in the IPCC exercises, to determine climate tested for the adaptation of numerical codes change on a local scale, both in mainland to future architectures, as well as integrated France and overseas, in order to deal with post-processing of ensemble forecasts. extreme phenomena, and to improve seasonal forecasting and its use. In the The year 2020 saw the consolidation of the mountains, the period ahead will prepare a Scientific Strategy 2020-2030, with new breakthrough with the development of a new exchanges with the members of the COMSI avalanche risk forecasting system for the and a presentation to the Governing Board. massifs, represented at a resolution of 250 Now approved, this Scientific Strategy will metres and integrating new space-based be used by the institution to build its next observations. More broadly, for all subjects, Contract of Objectives and Performance for the work will focus on taking into account the period 2022-2026. This Strategy is based the major space programmes announced on five main areas: up to 2030, but also the opportunities • Progress in the knowledge and anticipation offered by ‘low-cost’ space observation of extreme phenomena and their impacts, in and mass data. Artificial intelligence will a context of climate change be a major tool for processing these • Continuing the transition towards observation data, for post-processing integrated environmental modelling systems ensemble forecasts and for optimising our shared between forecasting and climate numerical models. Our efforts will also focus, • Adapt modelling tools to the operational in European and national coordination, on requirements of tomorrow’s computing adapting our numerical codes to the new architectures architectures of the next high-performance • Enhance the value of weather and climate computers. forecasts, in response to the expectations of internal and external beneficiaries At the international level, Météo-France • Strengthen the dynamics of national is implementing its policy of privileged and international cooperation, ensuring cooperation with the ECMWF on the Arpège/ convergence with ECMWF IFS global model, particularly on various 4 • Research Report 2020 aspects of physics that will soon bring participation in AllEnvi. It is a stakeholder Much of the research work of direct interest progress to our global forecasts. Météo- in the Data Terra Research Infrastructure to Météo-France is carried out by the CNRM. France is seeing the completion of the merger with its AERIS and THEIA Data and Services This is an opportunity to salute and wish of the Aladin and Hirlam consortia with the Centres, in Kalideos-Alpes under the aegis the best to the new CNRM management establishment on 1 January 2021 of the new of CNES, and participates in the ACTRIS-FR team (Samuel Morin and Nadia Fourrié), ACCORD consortium, which brings together and CLIMERI-France Research Infrastructures. which takes up its duties on 1 January 2021. 26 countries around the AROME-HARMONIE- In particular, AERIS is an opportunity and Other research work is also being carried out ALARO regional model. The management of a vector to facilitate the access of the within the LACy and in certain Directions of this new consortium has been entrusted to research world to the operational data of the the Establishment. All this work is detailed an engineer from Météo-France. Establishment. in the rest of this document. They are numerous, diverse, innovative and exciting. The Establishment is continuing its In terms of experimental and measurement They perfectly illustrate the broad spectrum policy of active participation in Eumetsat campaigns, the activity was strongly of our research activities, all of which are programmes, which will be reflected in impacted by the COVID context. It is gratifying essential to the Establishment and its future. our involvement in CDOP 4 of five of the that, despite this major difficulty, the SOFOG- “Satellite Application Facilities”. In 2020, in 3D campaign, included in the 2017-2021 But 2020 was the year of COVID with its a complicated context linked to the COVID, Contract of Objectives and Performance, difficulties and complications. This report is ADM-Aeolus observations (assimilation was able to achieve its objectives. On the the opportunity to salute all those involved, of wind profiles in the global model) and other hand, we regret the postponement to researchers, engineers, technicians, CFOSAT observations (assimilation of wave 2021 of the LIAISE campaign, which aims administrative staff, post-doc, PhD, trainees observations in the sea surface model) were to gain a better understanding of semi- and particularly those who have had to lead taken into account in the different models. arid regions and improve our forecasts, teams or supervise colleagues. It is also models. Preparations for the future MTG and particularly for the water budget. SAFIRE, important to salute the support teams and METOP-SG missions, which will carry new for its part, has had to postpone to 2021, in particular the IT department which played high-potential instruments, will continue, as or even cancel, the campaigns planned a crucial role during this period. Many thanks well as the preparation of certain instruments between March and September 2020. to all of them and let’s hope that 2021 will carried by the Sentinel programmes. Nevertheless, the EUREC4A campaign, see the end of the pandemic. Météo-France is maintaining its strong before the first lock-down, was able to participation in European projects, including proceed perfectly. For the replacement Copernicus, and is preparing its involvement of the Falcon 20 high-altitude research « Bonne lecture » with its ACCORD partners in the DestinE aircraft, Météo-France, along with the other project led by the ESA-EUMETSAT-ECMWF supervisory bodies of SAFIRE, supported the triumvirate. approach implemented, which was selected within the framework of PIA3+. Météo-France Marc Pontaud At the national level, Météo-France continues will support the project by maintaining its Météo-France to be involved in the scientific community, resources at the SAFIRE Unit but will not be scientific director, which is reflected in its various links with the able to participate financially in the initial Head of Higher Education CNRS, CNES and Universities, as well as its investment. and Research Research Report 2020 • 5 Numerical weather prediction and data assimilation A significant part of the research and development activities carried out in numerical weather prediction (NWP) during 2020 was devoted to the implementation of evolutions in the operational suite and the migration on the new Bull-AMD supercomputers and the preparation of the next version of NWP systems. New observations have been assimilated into the operational NWP suite, such as AMV (Atmospheric Motion Vectors) wind data from Goes17 satellite, Afirs and Tamdar aircraft data distributed by FLYTH, wind measurements by ESA Aeolus space-borne Doppler lidar and data from several global positioning systems by radio occultation (GNSS-RO). The latter two types of data have had a very positive impact on the objective scores. Many activities have been conducted to prepare the next e-suite to align specifically the spatial resolutions of the ensemble prediction systems (PEARP and PEARO) with the ones of the deterministic systems (Arpege and Arome-France), to increase the horizontal resolution of the Arome overseas systems and to transfer several important technical and scientific improvements from research to operations. Research activities have been performed in parallel to prepare the long-term evolutions of NWP systems. An « EnVar » assimilation scheme combining the variational and the ensemble approaches has been developed to improve the representation of the background error covariances and to take into account the temporal dimension in the « 4DEnVar » version. This « EnVar » algorithm is particularly relevant for the analysis of new variables, such as the hydrometeors of the Arome model. Some research activities on the dynamical cores have been conducted to improve the performance of the Arome model on massively parallel machines.