This deliverable presents an assessment of the observational capabilities for ocean mesoscale processes within the ObsSea4Clim project. The ocean mesoscale, which comprises eddies, fronts, and meanders at spatial scales of 10-100 km, is a dominant feature of the ocean circulation and plays a key role in the transport of heat, carbon, nutrients, and dissolved constituents, as well as pollutants. As such, mesoscale features are important agents for climate regulation, weather variability, and marine ecosystems. Observing the mesoscale is thus essential for climate services and ecosystem management. Here we present an assessment of selected nations' societal drivers and efforts to retrieve information about the ocean Mesoscale. The assessment uses the Rolling Review of Requirements framework. What is investigated is the reasons for countries to have access to information about the mesoscale, the approaches that are used to retrieve this information, the access to data, incl. own efforts to sample the ocean (e.g., time, space, parameter), an estimate on how suffi cient the data availability is to address the observational requirements (technology free) that should enable deriving the information needed, and recommendations on how eventually the observing (data and data accuracy, data integration) should be modifi ed to better address the nation's needs for information. This deliverable refl ects the assessments performed by project partners’ nations, namely ENS (France), GEOMAR (Germany), NERSC (Norway), and CSIC (Spain) and offers regional perspectives across key ocean areas, including the Atlantic Ocean and the Mediterranean, Labrador, and the Nordic Seas.
Publication Date: 2026-07-28