Products & Services

MedEOS aims to develop and produce high-resolution, gap-free maps of experimental Earth observation water quality products by employing data fusion techniques to combine the high temporal resolution of Sentinel 3 OLCI and high spatial resolution of Sentinel 2 MSI data. Moreover, MedEOS will develop, implement and demonstrate a methodology to produce an extensive tracking of river plumes in Mediterranean coastal waters with the use of EO products. MedEOS products and datasets are provided by means of a dedicated geoportal and an FTP repository. Requests to access the data should be directed to spatialops@deimos-space.com.

Earth Observation Direct Derived Water Quality Products

  • Total Suspended Matter (TSM) is a key element of water quality in coastal areas. It is a well-known parameter in ocean colour applications. A method using a single band, deemed robust for coastal turbid waters, is considered for this project’s application.
  • Turbidity is a water quality parameter closely related to TSM. The Turbidity Product will be designed according to the ISO 7027 definition: a quantitative measurement of “diffuse radiation” expressed in Formazin Nephelometric Units (FNU).
  • Chl-a Concentration is the main pigment in phytoplankton, and a key element in ocean-colour applications. Phytoplankton responsible for primary production through photosynthesis, and an indicator of the natural processes in the water environment.
  • Secchi Depth: The Secchi disk is the oldest instrument used to measure water transparency in the ocean (a disk which is lowered in the water). The Secchi depth is the depth at which the Secchi disk is no longer detectable by a human observer from the water surface.
  • Coloured Dissolved Organic Matter (CDOM) is a key element of water quality in coastal areas, and a well-known parameter in ocean colour applications. Its presence is mostly determined by freshwater outflow, and it can be used as a proxy for dissolved oxygen.

Earth Observation Indirectly Derived Water Quality Products

  • Global Environmental Anomaly Detector, based on statistical analysis, has been developed to automatically detect anomalies in coastal water quality, which will indicate probable anthropogenic pollution. It is based on 3 complementary triggers and associated thresholds, calibrated by the detection and analysis of anomalies from in situ datasets. It provides an experimental, autonomous and objective identification of every “abnormal event” present in the coastal area, without any a priori knowledge about the local pollution sources or type.
  • Faecal Bacteria Vulnerability Indicator is also provided as an Indirect Product, capturing the potential of resilience of faecal bacteria in coastal waters. While its objective is to quantify the vulnerability of coastal waters in case of a bacterial input, it cannot inform directly about the occurrence or not of such an input. Computed from both a biological index derived from the faecal bacteria decay rate, and a dynamic index derived from ocean currents, this indicator uses values of Kd, obtained from MedEOS Direct Products as input for the first. This is complemented by observation and modelled data sources from CMEMS and ECMWF, through a necessary spatial interpolation step, which may be a source of uncertainty when examining the FBVI product locally. The indicator is comprised between 0 and 1, where 1 is a very high vulnerability to faecal bacteria inputs. 
  • Eutrophication Vulnerability Indicator is computed from a combination of nutrient concentrations (from numerical models) and the Chlorophyll-a results generated in MedEOS. EVI is based on x , modified to result in a risk index ranging from 1 to 3 as to generalize results for the Mediterranean basin. Once more, this index does not directly indicate that a eutrophication event is ongoing, but rather serves as a measure of the vulnerability of a specific environment for such an event. As expected, variations in the data obtained from Direct Products and uncertainties for the nutrient numerical models largely affect the quality of this indicator results. Bias from the employed algorithm, originally calibrated in Maliakos Gulf, could affect results in other Mediterranean subareas, as well as thresholds to be considered to detect eutrophication events While a calibration step using data from other areas was performed in MedEOS, the generalization of the solution is still not perfect. 

River Plume Monitoring

  • River plume detection was also performed, based on the generated Direct Product parameters, mainly Turbidity and Total Suspended Matter, which are usually associated with river discharges. The detection is made on two different levels: while the primary river plume results from identifying normalized pixel-intensity gradient values above a predefined threshold, a secondary plume is obtained based on Probability Density Function (PSD) of the examined background water property (from lower to higher concentrations). These two contours correspond to two possible and complementary definitions of the river plume in coastal waters.