The SeaDataNet aggregated datasets over the Atlantic Ocean are regional ODV historical collections of all temperature and salinity measurements contained within SeaDataNet database and covering 3 European sea basins: North Arctic Ocean, North Sea, North Atlantic Ocean. Two versions have been published during SeaDataNet 2 and they represent a snapshot of the SeaDataNet database content at two different times: • V1.1 January 2014 • V2 March 2015 Each of them is the result of the Quality Check Strategy (QCS) implemented during SeaDataNet 2 that contributed to highly improve the quality of temperature and salinity data. The QCS is made by four main phases: 1. data harvesting from the central CDI 2. file and parameter aggregation 3. quality check analysis at regional level 4. analysis and correction of data anomalies. The aggregated datasets have been prepared and quality checked using ODV software.

SeaDataNet is a standardized infrastructure for managing the large and diverse marine data sets collected at sea by the oceanographic fleets, the ships of opportunity and the automatic observation systems. The SeaDataNet infrastructure network sand enhances the currently existing infrastructures, which are the national oceanographic data centres or data focal points of 34 countries, active in data collection. The networking of these professional data centres, in a unique virtual data management system provides integrated data sets of standardized quality on-line. As a research infrastructure, SeaDataNet contributes to build research excellence in Europe. SeaDataNet connects together more than 100 data centres aiming at preserving and making re-useable marine observations ranging from ocean physics to chemistry and biology. SeaDataNet infrastructure was implemented during the SeaDataNet project (2006-2011), grant agreement 026212, EU Sixth Framework Programme. The second phase, SeaDataNet 2 project (2011-2015), grant agreement 283607, EU Seventh Framework Programme has upgraded the SeaDataNet infrastructure into an operationally robust and state-of-the-art Pan-European infrastructure for providing up-to-date and high quality access to ocean and marine metadata, data and data products by: setting, adopting and promoting common data management standards, realizing technical and semantic interoperability with other relevant data management systems and initiatives on behalf of science, environmental management, policy making, and economy. SeaDataCloud project (2016-2020), grant agreement 730960, EU H2020 programme, aims at considerably advancing SeaDataNet Services and increasing their usage, adopting cloud and High Performance Computing technology for better performance.

SeaDataNet gridded climatologies are based on the SeaDataNet Temperature and Salinity historical data collection v1.1. For the Atlantic Ocean there are covering 2 European sea basins: North Arctic Ocean, and North Atlantic Ocean The preparation of the products has also improved the quality, the consistency and the overall coherence of the data made available by SeaDataNet. They have been computed using DIVA software.