New Opportunities for Turbid Water Atmospheric Corrections and Total Suspended Matter (TSM) Retrieval for OLCI.

KNAEPS, E.; RUDDICK, K.; DOGLIOTTI, A. I.; DOXARAN, D.; STERCKX, S.

Workshop; 3rd MERIS/(A)ATSR & OLCI/SLSTR Preparatory Workshop; 2012

The water-leaving reflectance in the SWIR is generally assumed to be zero ("black pixel assumption"), even for highly turbid waters. The idea is based on the high absorption of the pure water in this spectral region. This assumption has led to the development of atmospheric correction schemes for MODIS based on the SWIR (Wang, 2007, 2009). For more turbid waters this method provides an alternative to the NIR based approaches. Also the OLCI instrument on Sentinel 3 will provide data in this spectral range (OLCI band at 1020 nm).Only very recently (Knaeps et al., 2012) water leaving reflectance measurements in the SWIR were presented for the Scheldt river and related to the TSM concentration indicating the limits of this black pixel assumption and indicating the potential of this spectral region for TSM retrieval. Now also a sound theoretical basis is presented for the SWIR marine reflectance and new field measurements are presented to determine the variability of the water reflectance in the SWIR.