Multi-model multi-method multi-decadal ocean analyses from the ENACT Project

The main objective of the European ENACT (ENhanced ocean data Assimilation and Climate predicTion) project was to improve the ocean analyses that provide the initial global conditions for seasonal forecasts based on coupled general circulation models (GCMs). Advances were made with regards to the quality of forcing and assimilation data, and with several different data assimilation schemes that were implemented in various ocean GCMs. One major outcome was the production of an ensemble of ocean reanalyses for the period 1962 to 2001, as described in this article. Within the constraints of the experimental design, the ensemble provides estimates of the uncertainty in our knowledge of the ocean state through this period.