VALIDATION OF THE MERIS PRODUCTS FOR CHLOROPHYLL-A, SUSPENDED MATERIAL AND YELLOW SUBSTANCE IN THE SKAGERRAK

摘要

The activities, methods and results from the validation of the 2nd processed MERIS Level 2 data in the Skagerrak during 2002, 2003 and 2004 are described. The main data set is collected from the Skagerrak, but a few data are from the Kattegat and from the Danish and Norwegian West Coasts. The data were collected during traditional validation cruises and from a Ferrybox system onboard the MS Color Festival, traveling between Norway and Denmark. Water samples were investigated for optical properties and concentrations of chlorophyll-a, total suspended matter, yellow substance and bleached particle absorption. The validation is based on the MERIS Level 2 Reduced Resolution data available after the 2nd reprocessing of MERIS, starting in the autumn of 2005. The objective of the study has been to validate the new MERIS data products for coastal water (Case 2) after the improvements done in the 2nd processing. Based on the few data available the MERIS chlorophyll-a for Case 2 water is in agreement with the in situ data. The new conversion factor fits well for this area. Also for the total suspended material the retrieved concentration is close to the in situ values. No conclusion about the yellow substance products is possible at the present stage. The comparison performed here are based on observations from relative open areas, and we see that close to the coast and in the fjords the problems of atmospheric correction and/or environmental effects are significant. These problems need to be addressed and solved before the MERIS data can be used quantitatively in the Norwegian Fjords.