ABSTRACTS

Oral Session 2 | Monday, October 3, 14:20–14:40 | Abstract 550

Chlorophyll-a estimation from Sentinel-2 and Sentinel-3 observation in coastal waters

Chlorophyll-a concentration (Chl-a) is a crucial parameter for water quality monitoring in coastal waters. The Chl-a assessment in such environments is however complex and often relies on the use of multiple algorithms adapted to the optical complexity of these water masses. The principal aim of this study is to evaluate the performance of existing Chl-a inversion models (9 models) for estimating Chl-a for Sentinel-2/MSI and Sentinel-3/OLCI in coastal waters covering a large range of turbidity and to propose new models based on Multiple Band Ratios including visible and NIR wavelengths. The combination of these different formulations, relying on the use of Optical Water Types (OWTs) as a general frame in order to retrieve Chl-a from clear to highly turbid environments, was specifically evaluated on global data sets including in-situ Rrs and Chl-a as well as match-up validation data (N = 1097 and 568 respectively). As a result, the combined model allows an improvement in Chl-a estimation for both sensors (MAPD = 33.8% and 36.6% for MSI and OLCI respectively on the in-situ validation dataset). On overall limitation to estimate Chl-a towards the ultra-turbid environments was illustrated, further emphasizing the potential of hyper-spectral Rrs data to predict Chl-a in such optically extreme environments.

*Manh Tran, Laboratoire d’Océanologie et de Géosciences, 0000-0003-4770-5561

Vincent Vantrepotte, Vietnam Academy of Science and Technology, Space Technology Institute; Laboratoire d’Océanologie et de Geosciences, Université du Littoral Côte d’Opale, Université de Lille, CNRS, IRD, UMR 8187, LOG; LOTUS, Vietnam Academy of Science and Technology, University of Science and Technology of Hanoi

Hubert Loisel, Vietnam Academy of Science and Technology, Space Technology Institute; Laboratoire d’Océanologie et de Geosciences, Université du Littoral Côte d’Opale, Université de Lille, CNRS, IRD, UMR 8187, LOG; LOTUS, Vietnam Academy of Science and Technology, University of Science and Technology of Hanoi 

Xavier Meriaux, Laboratoire d’Océanologie et de Geosciences, Université du Littoral Côte d’Opale, Université de Lille, CNRS, IRD, UMR 8187, LOG

Kien Tran, Laboratoire d’Océanologie et de Geosciences, Université du Littoral Côte d’Opale, Université de Lille, CNRS, IRD, UMR 8187, LOG; LOTUS, Vietnam Academy of Science and Technology, University of Science and Technology of Hanoi

Son Nguyen, Laboratoire d’Océanologie et de Geosciences, Université du Littoral Côte d’Opale, Université de Lille, CNRS, IRD, UMR 8187, LOG; LOTUS, Vietnam Academy of Science and Technology, University of Science and Technology of Hanoi

Daniel Jorge, Laboratoire d’Océanologie et de Geosciences, Université du Littoral Côte d’Opale, Université de Lille, CNRS, IRD, UMR 8187, LOG