Calibration and validation of an algorithm for remote sensing of turbidity over La Plata river estuary, Argentina.

DOGLIOTTI, A.I.; RUDDICK, K.; NECHAD, B.; LASTA, C.; MERCADO, A.; HOZBOR, C.; GUERRERO, R. A.; RIVIELLO LÓPEZ, G.; ABELANDO, M.

Praga

Workshop; 5th EARSeL Workshop on Remote Sensing of the Coastal Zone; 2011

The La Plata River, located at 35°S on the Atlantic coast, is one of the largest waterways of South America. It carries a large amount of suspended particulate and dissolved organic matter, and is considered among the most turbid waters of the world. Very high values of total suspended matter have been reported in this region, with mean values ranging from 100 to 300 mg l-1 and extreme concentrations up to 400 mg l-1. Satellite sensors have shown to be the best tools available to map river plumes and to study their influence on the adjacent ocean. However, global algorithms for remotely estimating sediment concentration are not currently available. Moreover, such high sediment loads represent a challenge to atmospheric correction algorithms which usually rely on the assumption of zero water-leaving reflectance in the near infrared or short wave infrared part of the spectrum (black pixel assumption). In the extremely turbid waters of La Plata Estuary such assumptions are not valid. Algorithms for turbidity estimation using near infrared and the short wave infrared bands (858nm and 1240nm) of the MODIS-Aqua sensor are tested here. The derived results were found consistent with known values and their spatial distribution in the region.