Synergistic Use of Ferrybox and Envisat Data with the Aid of a Hydrodynamic Transport Model

An automatic measuring system called FerryBox was installed on a ferry travelling between Cuxhaven (Germany) and Harwich (Great Britain) enabling on-line oceanographic and biological measurements such as salinity, temperature, fluorescence, turbidity, oxygen, pH, and nutrient concentrations. The high frequent sampling of data allows to detect even short-term events. Observations made along the ferry transect reveal characteristic phenomena such as high salinity inflow through the Channel into the southern Bight, algal bloom dynamics and related oxygen and pH changes. For the same time period data from ENVISAT (MERIS) was used to retrieve water content concentrations of chlorophyll, total suspended matter and yellow substance. Combination of these in-situ on-line observations with remote sensing reveales an improved knowledge of coastal water status. Examples of the synergy between both operational measuring strategies are shown, both for large scale algal blooms in the North Sea as well as for local intense but short term blooms in the German Bight. Coherence of the data sets was improved by using hydrodynamic transport models in order to obtain synoptic overviews of the remotely sensed and FerryBox related parameters. The importance of future applications of these combination of methods for monitoring of coastal waters is emphasised.