WP2 - In-situ data sets collection and archiving

WP2- In-situ data sets collection and archiving lead by NIMRD aims at gathering the historical datasets necessary for supporting 1) the development and validation of the algorithms developed in WP3-5 for producing ocean color, altimetry and Sea Surface Salinity (SSS) products and 2) the production of new products in WP6 (e.g. mapping of the mesoscale circulation, oxygen dynamics). Various datasets are gathered in a Database (EO4SIBS Data Access) adapted to ingest historical and airborne data, to visualize and download them. Freely available (open access), quality controlled and validated datasets from reliable providers (like SeaDataCloud, EMODNET, AERONET-OC, WOD, PSML, BGC-Argo, etc) which hold Black Sea data are targeted to support ocean colour, altimetry and sea surface salinity products and model development and validation. Access to restricted datasets was required from identified sources (like national databases). In case of gaps in terms of data availability, the in-situ data collected within the framework of the Romanian Monitoring oceanographic cruises complement these gaps. The detailed description of the available historical and new datasets is provided in a Dataset user manual.

WP3 - Ocean colour products

Work Package 3 is focused on the development and validation of Ocean Colour Products. After an initial evaluation of the performance of existing algorithms and products, several regional approaches were defined and implemented. A classification methodology was first derived, useful for differentiation of water masses in optical distinct sub-regions. The algorithm is based on the principles of the method developed by Morel and Bélanger (2006) which distinguished Case-1 and Case-2 waters. This simple, but more operational approach was adapted to the regional conditions and can distinguish 3 water classes.

Regional inversion algorithms were also developed and documented for the estimation of several biogeochemical indicators based on remote sensing reflectance values. These indicators include water turbidity, Suspended Particulate Matter (SPM) and chlorophyll-a concentration. For the first two, a combination of two single-bands empirical algorithms, using both the red and near-infrared spectral bands, proved to perform very well, given the available in-situ data available for calibration. The later was developed as a combination between a neural network and a blue-to-green ratio approach. Transition from one algorithm to another is performed using a blending methodology.

WP4 - Altimetry Products

WP4 - Altimetry Products: Development and Validation – is led by CLS and aims to provide the project with the best altimeter products. The WP4 includes 3 main tasks: 1) Assess the quality of a 25-year existing altimetry product focusing on the Black Sea coastal areas. 2) Propose innovative processing to generate higher resolution altimeter products for the WP6 purpose. Two products lines are considered: an along-track (L3) product deduced from high frequency (20 Hz) SAR data; and a multi-mission gridded (L4) product, using the previous L3 in input. Both are targeted for the coastal areas where mesoscale is enhanced. Different in situ measurements provided by WP2 are used for validation 3) Promote these products to potential external users, and more specifically through the CMEMS (Copernicus Marine Service) Model Forecast Centers (MFCs).

WP6 - Science case studies and valorisation of the new EO4SIBS products

WP6 is dedicated to science case studies and valorisation of the new EO4SIBS products. A strong emphasis has been set on studying the dynamics of eddies, which are swirls forming in the sea’s circulation fields. Eddies are important features to understand the dynamics of physics and chemistry in the oceans, because they can capture water masses in their core and can subsist for up to several years! In the Black Sea, they often control the exchanges of materials and energy between the coastal and central region. As they induce vertical circulation along their body they’re also known to play an important role in the ventilation of the stratified Black Sea. Since those structures can mostly be observed by their influence of the water surface elevation, the enhancement of altimetry products is essential to catch their dynamics in an inner basin such as the Black Sea. However, it’s mostly the vertical structure below that matters. For this we rely on collocated in-situ sampling and modelling data. Another important task of WP6 concerns the assimilation of enhanced satellite products in operational marine models. In particular, the CMEMS Marine forecasting center provides European citizens with real-time information about the status of the Black Sea. Acquiring and ingesting better observations about chlorophyll content, salinity and sea surface elevation allows to increase the predictions accuracy.