Are the empirical relationships describing the bio-optical properties of case 1 waters consistent and internally compatible?

Andre Morel (1)

1 LOV - Laboratoire d'océanographie de Villefranche

Empirical relationships have been previously established in case 1 waters, by which some inherent optical properties such as particle absorption, scattering and attenuation coefficients, or some apparent properties, such as diffuse attenuation, reflectance, and color band ratios, have been statistically related to the chlorophyll concentration [Chl]. These relationships are at the basis of most of the bio-optical models; with their uncertainties, they describe average trends along the [Chl] range of certain optical properties, around which a natural variability occurs. Through closure exercises and inversions, it is examined whether the presently available, and independently established, empirical relationships form a set of compatible equations. This approach also allows other, less frequently measured properties to be inferred, such as the absorption by dissolved colored matter, ay, which appears to be larger than often anticipated and to behave on average as a power function of [Chl] in case 1 waters. The spectra of the single scattering albedo of particulate matter are also derived; whatever [Chl], they distinctly exhibit the imprint of the algal pigment absorption. The consistency between the present approach and the GSM inversion scheme (developed by Garver, Siegel, and Maritorena) is also verified. Globally, it is found that within their own uncertainty (resulting from measurements) and variability levels (resulting from natural causes), the main historical relationships describing the bio-optical state of case 1 waters appear to be mutually coherent and compatible.

Domaines: Océanographie

Andre Morel. Are the empirical relationships describing the bio-optical properties of case 1 waters consistent and internally compatible?. Journal of Geophysical Research. Oceans, 2009, 114, ⟨10.1029/2008JC004803⟩. ⟨hal-03505030⟩