Recommendations on data harmonization for ocean observation networks

The ocean observing system needs to be ensured by high-level integration and coordination to guarantee its longterm sustainability, efficient accessibility and usability by a wide range of users. Enormous advancements and efforts toward these objectives have been already conducted in Europe, partly through the activities of the IOC-UNESCO's International Oceanographic Data and Information Exchange (IODE) and EuroGOOS DATAMEQ working group, although there is still room for additional progress and gaps to be addressed. During the past two decades, a series of standards for data and metadata formats as well as exchange protocols have been established within the marine community where projects, organizations and data integrators like JCOMM, RDA (Research Data Alliance), EuroGOOS, EMODnet, SeaDataNet and Copernicus played a significant role. Taking into consideration that harmonized data are a key element in maintaining a usable and interoperable ocean observing system, this paper aims to provide some recommendations for the harmonization of the marine in situ networks involved in EuroSEA, which would be a useful product for the European data integrators, particularly EMODnet, SeaDataNet and Copernicus Marine service. This document proposes recommendations to enhance the in situ networks based on the assessment of what has been previously done.