An improved correction method for field measurements of particulate light backscattering in turbid waters

DOXARAN, D.; LEYMARIE, E.; NECHAD, B.; DOGLIOTTI, A. I.; KNAEPS, E.

Darmstadt

Encuentro; International Ocean Colour Science (IOCS) Meeting; 2013

Light backscattering by suspended particles in natural waters is a key parameter in marine optics and for ocean colour remote sensing purposes. The particulate backscattering coefficient is highly correlated to the concentration of suspended solids [1] and its spectral variations are representative of the particle size distribution [2], especially in sediment-dominated coastal and estuarine waters. However field measurements of the particulate backscattering coefficient in turbid waters is problematic mainly due to (i) saturation effects of most sensors developed for the open ocean and (ii) the strong light attenuationalong the sensor pathlength which is difficult to accurately account for in highly-reflective waters. Based on results obtained using Monte Carlo simulations, we present an improved correction method for such measurements. The method takes into account the absorption, scattering and particulate volume scattering function of the sampled waters. It is applied to field measurements from the Río de la Plata estuary (Argentina) and a factor 2 difference is observed with the standard correction method. Based on optical closure with the water reflectance signal also measured in the field, we quantify the improvement of thenew correction method.