Coastal DIAMONDS (Danish IntegrAted Marine ObservatioN & Data System). Integrating real time data to strengthen monitoring capabilities in Danish marine waters

Denmark is transitioning toward a more holistic and data-driven approach to marine environmental monitoring. Historically, Denmark relied on ship-based sampling. While thorough, this method limits frequency and spatial coverage and requires considerable resources. Although new technologies, such as Earth Observation (EO), buoy-mounted sensors, and autonomous platforms, are increasingly adopted worldwide, they are not yet systematically integrated into European monitoring programmes in support of e.g., Water Framework Directive (WFD).

A major challenge in assessing ecological health is the reliable tracking of summer chlorophyll-a concentrations and the assessment of oxygen depletion events. These parameters form the basis of the two use-cases within the Coastal DIAMONDS project under the Copernicus Marine Service National Collaboration Programme (NCP). Chlorophyll serves as a critical indicator of eutrophication cf. WFD and oxygen depletion events is fundamental to assess impacts to habitats and ecosystems.

Coastal DIAMONDS represents a shift toward a more integrated solution in a new operational framework designed to support key European directives. The project assimilates Copernicus Marine Service’s real-time datasets, which includes measurements from buoys, bottle sampling, and ferry boxes into regional and then down-scaled national biogeochemical models, complementing national monitoring efforts. Copernicus Marine data is specially featured due to its capabilities of providing open data from all sectors.

This project parallels the “Integrated Marine Monitoring (IMM)” joint initiative between Danish Agency for Green Transition and Aquatic Environment (SGAV) and DHI, with their real time in-situ platform providing model results and sharing monitored data from various sources, complementing the data-sources beyond national data from National Monitoring Programme for the Aquatic Environment and Nature (NOVANA, Nationale Overvågningsprogram for Vandmiljø og Natur).

At the core of the system is a modelling framework built on the DHI MIKE suite. Advanced data assimilation methods, including Optimal Interpolation and the Ensemble Kalman filter, are applied to calibrate environmental variables against observed data. This enables accurate and timely insights into marine ecosystem dynamics. The model complex constitutes several mechanistic models covering Danish water bodies in the North Sea as well as in the Baltic Sea, then downscaling from North Sea and Baltic Sea scale to costal bays and enclosed estuaries.

All typical biogeochemical parameters from the operational models, including chlorophyll-a and oxygen addressing the use-cases, are intended for publication on Denmark’s national environmental data portal. This ensures that researchers and citizens can access up-to-date information and follow national efforts toward improved marine ecosystem health.