Pierre Thibaut (CLS, France); Malcolm McMillan (University of Lancaster, UK); Sara Fleury (LEGOS, France); Marion Bocquet (LEGOS, France); Eero Rinne (FMI, Finland); Frank Fell (Informus, Germany); Bruno Picard (Fluctus, France); Fernando Nino (LEGOS, France); Angelica Tarpanelli (IRPI, Italy); Emma Woolliams (NPL, UK); Hélène Roinard (CLS, France); Victor Quet (CLS, France); Annabelle Ollivier (CLS, France); Jean-Alexis Daguzé (CLS, France); Beatriz Calmettes (CLS, France); Marie-Laure Fréry (CLS, France); Mathilde Simeon (CNES, France); Pierre Féménias (ESA/ESRIN, Italy)

In the framework of the European Long Term Data Preservation Program (LTDP+) aiming at generating innovative Earth system data records named Fundamental Data Records (basically level 1 altimeter and radiometer data) and Thematic Data Records (basically level 2+ geophysical products), ESA/ESRIN launched a reprocessing activity of ERS-1, ERS-2 and ENVISAT altimeter and radiometer dataset. A large consortium of thematic experts has been formed to take in charge these activities which are 1) to define products including the long, harmonized record of uncertainty-quantified observations, 2) to define the most appropriate level 1 and level 2 processing, 3) to reprocess the whole times series according to the predefined processing and, 4) to validate the different products and provide them to large communities of users focused on the observation of the atmosphere, ocean, coastal, hydrology, sea ice, ice sheet regions.
The project reached its end in 2023 and the FDR4ALT products have been finalized and delivered to ESA. They should me made available to the public during the fall of 2023.
The objective of this talk is to present to OSTST members these 8 distinct products in terms of content and performances. For each of them, the FDR4ALT product outperforms the previous reference, namely REAPER for ERS and V3.0 for ENVISAT.
At level-1, radiometer products have been entirely reprocessed from level-0, showing great improvements . On the altimeter side, the starting point was the existing products (REAPER and V3.0) but several evolutions have been made at level-1 to improve product quality.
At level-2P, a long list of improvements has been made to ensure having the best products possible for each surface (Atmosphere, Ocean & Coastal, Ocean waves, Inland Waters Sea-Ice and Land-Ice). This talk will detail all these improvements as well as the validation results for each product.
The FDR4ALT products will be considered as the new reference products for ERS and ENVISAT. Several manuscripts are now being prepared to present their excellent performances in scientific journals. One paper by M.Bocquet et al. related to the performances of the Sea-Ice TDP, has already been published (https://doi.org/10.5194/tc-17-3013-2023)