CORE-CLIMAX will coordinate the identification of available physical measurements, which can be reconciled with previously existing data records, to form long time series. It will help to substantiate how GMES observations and products can contribute to climate change analyses, by establishing the extent to which GMES observations complement existing Climate Data Records (CDR).With GCOS, GMES and ESA CCI projects, and EUMETSAT including its Satellite Application Facility (SAF) network, coordination will also take place with specific efforts to be undertaken by new FP7 GMES projects to further upgrade their product catalogues to include this climate relevant validation and information and lay the observational basis for service activities. CORE-CLIMAX will identify the integration of ECVs into the reanalysis chain by proposing a feedback mechanism ensuring that the results of the re-analysis process get appropriately reflected into updates of the ECVs. Together with intercomparing different reanalyses, CORE-CLIMAX will contribute to establish a European truly coupled gridded re-analysis which incorporates full exchanges and interactions between atmosphere, ocean, land, including the hydrological cycle.Specific objectives:1 Coordinate with GMES ongoing activities and contribute to the formulation of the GMES climate service theme (GCOS, FP7 GMES and climate change projects, ESA CCI projects, EUMETSAT including its SAF network and EUMETNET as part of the European Meteorological Infrastructure)2 Propose a structured process for delivering ECVs through the stepped and quality controlled elaboration of CDR, the latter being derived from prioritisation of the most appropriate input data sets;3 Propose a validation process aiming at qualifying the accuracy of the climate variables;4 Propose a feedback mechanism ensuring that the results of the re-analysis process get appropriately reflected into updates of the CDR;5 Propose a process to compare reanalyses.