The Sentinel satellites of the Copernicus programme offer an excellent opportunity for monitoring the state of the Baltic Sea. The current constellation provides daily coverage in moderate resolution (S3 OLCI with 300 m pixels) and twice-weekly coverage in high resolution (S2 MSI with 10-60 m pixels) with spectral characteristics suitable for estimating turbidity, Chlorophyll a and CDOM. These are related to the land-to-sea fluxes of carbon that occur in coastal zones. With this in mind the goal of the ESA funded project Baltic+ SeaLaBio (Sea-Land Biogeochemical linkages, from 2018 to 2020) was to develop methods for assessing carbon dynamics and eutrophication in the Baltic Sea through integrated use of EO, models, and ground-based data.
The project has now ended. As a summary of the impacts, the developments done in the SeaLaBio project have advanced the state-of-the-art in three important fields:
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Biogeochemical modelling: The ERGOM model can now utilize EO based aCDOM values as input data and, as a result, provide more reliable estimates of light attenuation in water, which potentially provides more realistic simulations of several other state variables. This has consequences especially in the norther parts of the Baltic Sea where CDOM has a large effect on water transparency.
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EO data processing: A new method for atmospheric correction of satellite images – based on combining the advantages of Polymer & C2RCC – can now provide more reliable water leaving reflectance values. This is a major step towards the formulation of an optimal AC for the Baltic Sea. A band ratio algorithm based on Baltic+ AC results was established and provided better aCDOM values than the other current processors.
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Use of EO for monitoring carbon fluxes: EO based data can e.g. provide information about the Total Organic Carbon loads from rivers.
For more details, please see the documents in the Results section of this website. The data we have generated is publicly available. See the Data access section for details.
The project is under ESAs EO4society programme and part of the Baltic Regional Initiative activities. It is also linked to the Baltic Earth community.