Abstract. As part of the European Space Agency's Climate Change Initiative, new sets of satellite observation products have been produced for Essential Climate Variables including ocean colour, sea surface temperature, sea level and sea ice. These new products have been assimilated into a global physical-biogeochemical ocean model, to create a set of 13-year reanalyses at 1° resolution and 3-year reanalyses at 1/4° resolution. In a series of experiments, the variables were assimilated individually and in combination, in order to assess their consistency from a data assimilation perspective. The satellite products, and the reanalyses assimilating them, were found to be consistent in their representation of spatial features such as fronts, sea ice extent and bloom activity. Assimilating multiple variables together often resulted in larger mean increments for a variable than assimilating it individually, revealing ways in which the model and assimilation scheme could be improved. Sea surface fugacity of carbon dioxide had lower errors against independent observations in the higher resolution simulations, and was improved by assimilating ocean colour or sea ice concentration, but degraded by assimilating sea surface temperature or sea level anomaly. Phytoplankton biomass correlated more strongly with net air-sea heat fluxes in the reanalyses than chlorophyll concentration did, and the correlation was weakened by assimilating ocean colour data, suggesting that studies of phytoplankton bloom initiation based solely on chlorophyll data may not provide a full understanding of the underlying processes.
Assessing the role and consistency of satellite observation products in global physical–biogeochemical ocean reanalysis