Spring mean and maximum chlorophyll a (chl a) concentrations are main factors to determine the eutrophication status of the Belgian waters as agreed within OSPAR in 2002. Other important assessment parameters to measure the degree of nutrient enrichment - the amounts of inorganic
phosphate and nitrogen in winter - appeared to be above thresholds for most measurements performed in the period 1974-2002. As the standard in situ monitoring programme does not give a clear picture of the temporal and spatial distribution of chl a, it is logical to complement these measurements with optical remote sensing. However, chlorophyll concentrations derived from sensors such as SeaWiFS are unreliable in the Case 2 waters of this region because of high particulate and dissolved yellow substance absorption. Another important limitation of ocean colour sensors is the amount of useful images due to cloud cover. The combination of data from different ocean colour sensors in order to enable a better temporal coverage might be hampered by the different chlorophyll retrieval algorithms used. This study compares different global chl a algorithms (MODIS, SeaWiFS, MERIS) as well as a turbid water algorithm for the Southern North Sea. This is done by running the different algorithms on in situ reflectance spectra collected at 107 stations in the period 2001-2002 over the Southern North Sea and comparing them with in situ chl a concentrations, as well as by running the algorithms on a MERIS image of the 29th of July 2002. Based on this validation the accuracy of these products and their suitability for eutrophication monitoring in
the Southern North Sea are assessed.
Auteurs et éditeurs
De Cauwer, Vera
Fournisseur de données
Known for being a trendsetter in higher education and applied research internationally, the Namibian University of Science and Technology (NUST) aims to become the leading university in Africa. The Department of Land and Property Sciences (DLPS) offers relevant degrees at undergraduate and post-graduate level including master and doctorate degrees. The Department of Land and Property Sciences (DLPS) at NUST together with the Integrated Land Management Institute (ILMI) are playing a leading role in research and outreach in the field of land governance and administration.