We are developing a coupled atmosphere-ocean data assimilation system to produce consistent climate reanalyses of the coupled Earth system.
ECMWF has led two successive international research projects funded by the European Commission (ERA-CLIM and ERA-CLIM2). The main goal of these projects was to develop suitable input observations and improved data assimilation methods for climate reanalysis.
ERA-20C is ECMWF's first atmospheric reanalysis of the 20th century, from 1900-2010. It assimilates observations of surface pressure and surface marine winds only. It is an outcome of the ERA-CLIM project.
CERA-20C extends the climate reconstruction of the Earth system to the ocean and the sea ice, providing a 10-member ensemble of reanalyses, from 1901-2010. It is based on the CERA assimilation system, which assimilates simultaneously surface pressure and marine wind observations as well as ocean temperature and salinity profiles. It is an outcome of the ERA-CLIM2 project.
CERA-SAT is a reanalysis dataset spanning 8 years between 2008 and 2016. It has been produced within the scope of the ERA-CLIM2 project as a proof-of-concept for a coupled reanalysis with the full observing system available in the modern satellite age. It has been created using the CERA assimilation system and comprises an ensemble of 10 individual members.