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OPTICAL REMOTE SENSING OF THE EUROPEAN SEAS: 
HISTORICAL RECORD AND MONITORING PROGRAMMES. 
Vittorio Barale 
Commission of the European Communities 
Joint Research Centre 
Institute for Remote Sensing Applications, Marine Environment Unit 
IRSA/ME (tp 272) JRC CEC 
Ispra (VA) 21020, Italy 
ISPRS Commission VII/Working Group 8 
ABSTRACT 
The European Seas are threatened by dramatic ecological problems consequent to countless economic 
and recreational activities. Adequate tools are needed to investigate the large variety of environmental 
situations occurring in these marginal and enclosed basins, and their space and time variabilities. The use 
of optical remote sensing for monitoring marine phenomena has been steadily growing, in recent years, 
due the potential of surface color data for generating novel information on biological, geochemical and 
physical processes of the sea. The historical data set collected by the Coastal Zone Color Scanner 
(CZCS), from late 1978 to early 1986, provides examples of such capabilities. A statistical time series 
using the complete CZCS coverage of the European marine regions has been developed in the framework 
of the Ocean Color European Archive Network (OCEAN) Project, which was established by the 
Commission of the European Communities (CEC) and the European Space Agency (ESA) in support of 
current research activities and in preparation for the future space missions. The CZCS value-added data 
show that marginal and enclosed seas are different, in many respects, from the rest of the world oceans. 
The data set documents the long-term evolution of pigment patterns in the surface layer of the 
Mediterranean Sea and the Black Sea, the North Sea and the Baltic Sea, and connecting basins, and the 
contribution that optical observation systems can give to the monitoring of environmental conditions. 
Moreover, it suggests that the processes occurring in such seas are strongly influenced by interactions 
between freshwater inflow, coastal boundaries, exchanges through channels and straits, and bottom 
topography. Variations in sea surface color, due to the presence and abundance of water constituents 
(primarily chlorophyll-like pigments), give indications concerning topics such as coastal runoff, potential 
pollution sources, water quality and circulation, plankton dynamics, and space/time heterogeneities 
which result from a variable environmental forcing. This work will constitute the basis, in the near future, 
for the exploitation of new observations (i.e. those by the Sea-viewing Wide-Field-of-view Sensor, Sea 
WIFS, in 1994; the Ocean Color and Temperature Scanner, OCTS, in 1995; the Medium Resolution 
Imaging Spectrometer, MERIS, in 1988) through the joint CEC/ESA Programme on Ocean Color 
Techniques for Observation, Processing & Utilization Systems (OCTOPUS). 
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