Evaluation of derived total suspended matter products from Ocean and Land Colour Instrument Imagery (OLCI) in the inner and mid-shelf of Buenos Aires Province (Argentina)

DELGADO ANA LAURA; PRATOLONGO PAULA; GOSSN JUAN IGNACIO; ARENA MAXIMILIANO

Dubrovnik

Congreso; Ocean Optics XXV; 2018

The Ocean and Land Colour Instrument Imagery (OLCI) sensor provides moderate spatial and temporal resolution of marine data, becoming a promising tool for monitoring environmental changes in coastal waters. Therefore, it is fundamental to test and validate the resulting products from diverse algorithms to ensure the quality of the data. The complex waters of southern Buenos Aires Province inner and mid-shelf, characterized by the presence of estuaries and river inputs, are highly influenced by total suspended matter (TSM) variability (Figure 1). In this study, we evaluate the performance of four TSM products in different waters (estuarine, coastal and mid-shelf waters) with in situ data.OLCI-Sentinel 3 Daily level 1 (full resolution) and L2 (water full resolution) data at 300 m spatial resolution were downloaded from the Eumesat web page (https://coda.eumetsat.int/). The extracted L1A files for the study area were processed using Snap software to obtain L2 TSM product. The performance of four TSM products in different waters were evaluated. Three products were obtained using neural networks (NN):  OLCI L2 ESA standard product (TSM_NN), Case 2 Regional Coast Colour processing chain using a standard (C2RCC_STD) and a new set of NN (C2RCC_NEW) provided by Brockmann Consult (?); the fourth product was obtained using an alternative Baseline Residual Atmospheric Correction approach (Gossn et al., 2017) combined with the Nechad 2010 TSM algorithm (BLR_NCHD). Despite the complexity and diversity of the studied waters, reasonable results were found when comparing the TSM estimates with in situ data. Knowing that there is an over estimation in estuarine and inner shelf waters, seasonal and inter-annual variability could be reproduced. Future work directed to improve TSM retrieval should consider the evaluation of the conversion factor from backscattering to TSM used in NN algorithms. Additionally, atmospheric correction procedures should be evaluated using in situ measurements of water reflectance.