CHL Maps of the Dutch Coastal Zone: A Case Study within the REVAMP Project

This paper introduces the EC-FP5-sponsored REVAMP project which aims to produce an atlas of validated CHL-maps for the North Sea based on MERIS observations. In the first part the aim and setup of the project are outlined. Within REVAMP a large database has been set up containing historic and recent (2002 and 2003) measurements of reflectance, concentrations and IOP data from multiple regions of the North Sea. This database will be used to develop and calibrate the algorithms for processing MERIS images to chlorophyll-a maps. A processor was built to accommodate the testing of a host of new CHL algorithms on seaborne and MERIS observed spectra and to use for the production of the final CHL maps for the Atlas. In the second part of the paper a qualitative intercomparison is done between the resulting CHL maps based on MERIS-RR images from two new CHL algorithms and the standard Algal Pigment II index. The conclusions are that the patterns of CHL from entirely different CHL algorithms show large similarities. Still the relative concentration ranges differ per image so there is a real need for regional calibration/validation of the CHL products.