Climare Reanalysis at ECMWF
Thpaut, Jean-Nol; Dee, Dick; Balsamo, Gianpaolo; Alonso Balmaseda, Magdalena; Engelen, Richard; Simmons, Adrian

Climate reanalysis is increasingly seen as critical for understanding the processes associated with climate change and informing future climate change scenarios. Reanalysis combines information from past and present meteorological observations with modern forecast models, using data assimilation techniques originally developed for numerical weather prediction.
This presentation will review past and current reanalysis activities at ECMWF and outline plans for future development of a coupled climate reanalysis. Global reanalyses of the atmosphere, ocean, land surface, and atmospheric composition are closely tied to the development of the ECMWF data assimilation and forecasting system and its extended capabilities. Reanalysis data also serve numerous external users in a wide range of applications, including climate monitoring and research. New developments in reanalysis at the Centre are focused on extending the length of atmospheric reanalyses, developing a coupled data assimilation capability, and continually expanding and improving the use of past and current observations, in particular from satellites.
Reanalysis provides a unifying framework for integrating climate information from many sources whilst imposing multivariate consistency throughout. It is therefore a unique resource for the ESAs Climate Change Initiative (CCI). The presentation will review ECMWFs involvement in this initiative and describe ambitions to play a prominent role in the observations and monitoring component of the future Copernicus Climate Services, as well as the WMO Global Framework for Climate Services.