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JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 112, C06003, doi:10.1029/2006JC004007, 2007

Estimation of light penetration, and horizontal and vertical visibility in oceanic and coastal waters from surface reflectance

Maéva Doron

ACRI-ST, 260 route du Pin Montard, Sophia Antipolis, France
Laboratoire d’Océanographie de Villefranche, Université Pierre et Marie Curie-Paris6, Villefranche-sur-Mer, France
Laboratoire d’Océanographie de Villefranche, CNRS, Villefranche-sur-Mer, France


Marcel Babin

Laboratoire d’Océanographie de Villefranche, Université Pierre et Marie Curie-Paris6, Villefranche-sur-Mer, France
Laboratoire d’Océanographie de Villefranche, CNRS, Villefranche-sur-Mer, France


Antoine Mangin

ACRI-ST, 260 route du Pin Montard, Sophia Antipolis, France


Odile Hembise

ACRI-ST, 260 route du Pin Montard, Sophia Antipolis, France


Abstract

We present algorithms for the estimation of the vertical diffuse attenuation coefficient, K d (m−1), and the beam attenuation coefficient, c (m−1), at 490 nm from irradiance reflectance. Our aim is to retrieve as analytically as possible [K d(490) + c(490)]−1, a proxy for vertical visibility. The two algorithms are based on the semianalytical retrieval of the absorption coefficient a (m−1) and the backscattering coefficient b b (m−1) from reflectance at two wavelengths, 490 and 709 nm. The use of a near-infrared wave band allows a small number of simple assumptions to be made, (1) light absorption at 709 nm is only due to pure seawater, and (2) there exists a constant ratio between the particulate backscattering coefficients at 490 and 709 nm. To estimate c(490), we developed an empirical relationship between b and b b for particles. Algorithm development, testing, and validation are achieved using data from the literature, a synthetic data set, and a large in situ data set of inherent and apparent optical properties measured in various environments. The algorithms are found to be valid both in coastal and oceanic waters, and largely insensitive to regional peculiarities in the inherent optical properties. The values of K d(490) and c(490) are retrieved within a factor of 2.21 and 2.91 (95% confidence interval), respectively, using independent in situ data sets. This performance for K d(490) is better or comparable to that of recently published algorithms. This study opens the way to the development of simple semianalytical ocean color algorithms that make the best use of spectral information.

Received 9 November 2006; accepted 24 January 2007; published 5 June 2007.

Keywords: Visibility; light penetration; attenuation; Case 2; ocean color; remote sensing.

Index Terms: 4264 Oceanography: General: Ocean optics (0649); 0649 Electromagnetics: Optics (4264); 4275 Oceanography: General: Remote sensing and electromagnetic processes (0689, 2487, 3285, 4455, 6934); 0689 Electromagnetics: Wave propagation (2487, 3285, 4275, 4455, 6934); 2487 Ionosphere: Wave propagation (0689, 3285, 4275, 4455, 6934); 3285 Mathematical Geophysics: Wave propagation (0689, 2487, 4275, 4455, 6934); 4455 Nonlinear Geophysics: Nonlinear waves, shock waves, solitons (0689, 2487, 3280, 3285, 4275, 6934, 7851, 7852); 6934 Radio Science: Ionospheric propagation (0689, 2487, 3285, 4275, 4455); 4271 Oceanography: General: Physical and chemical properties of seawater.

Subscriber Access to Full Article (Nonsubscribers may purchase for $9.00, Includes print PDF, file size: 516023 bytes)

Citation: Doron, M., M. Babin, A. Mangin, and O. Hembise (2007), Estimation of light penetration, and horizontal and vertical visibility in oceanic and coastal waters from surface reflectance, J. Geophys. Res., 112, C06003, doi:10.1029/2006JC004007.