Maps of surface chlorophyllous pigment (Chl a + Pheo a) are currently produced from ocean color sensors. Transforming such maps into maps of primary production can be reliably done only by using light-production models in conjunction with additional information about the columnintegrated pigment content and its vertical distribution.As a preliminary effort in this direction, -4,000 vertical profiles of pigment (Chl a + Pheo a) determined only in oceanic Case 1 waters have been statistically analyzed. They were scaled according to dimensionless depths (actual depth divided by the depth of the euphotic layer, Z,) and expressed as dimensionless concentrations (actual concentration divided by the mean concentration within the euphotic layer). The depth Z,, generally unknown, was computed with a previously developed bio-optical model. Highly significant relationships were found allowing (C>,,,, the pigment content of the euphotic layer, to be inferred from the sur!ace concentration, C,, observed within the layer of one penetration depth. According to their C,, values (ranging from 0.01 to > 10 mg m-3), we categorized the profiles into seven trophic situations and computed a mean vertical profile for each. Between a quasi-uniform profile in eutrophic waters and a profile with a strong deep maximum in oligotrophic waters, the shape evolves rather regularly. The wellmixed cold waters, essentially in the Antarctic zone, have been separately examined. On average, their profiles are featureless, without deep maxima, whatever their trophic state. Averaged values of p, the ratio of Chl a to (Chl a + Pheo a), have also been obtained for each trophic category.The energy stored by photosynthesizing algae, once normalized with respect to the integrated chlorophyll biomass (C),,, is proportional to the available photosynthetic energy at the surface via a parameter #*, which is the cross-section for photosynthesis per unit of areal chlorophyll. By taking advantage of the relative stability of #*, we can compute primary production from ocean

The ocean color component of the Aerosol Robotic Network (AERONET-OC) has been implemented to support long-term satellite ocean color investigations through cross-site consistent and accurate measurements collected by autonomous radiometer systems deployed on offshore fixed platforms. The AERONET-OC data products are the normalized water-leaving radiances determined at various center wavelengths in the visible and near-infrared spectral regions. These data complement atmospheric AERONET aerosol products, such as optical thickness, size distribution, single scattering albedo, and phase function. This work describes in detail this new AERONET component and its specific elements including measurement method, instrument calibration, processing scheme, quality assurance, uncertainties, data archive, and products accessibility. Additionally, the atmospheric and bio-optical features of the sites currently included in AERONET-OC are briefly summarized. After illustrating the application of AERONET-OC data to the validation of primary satellite products over a variety of complex coastal waters, recommendations are then provided for the identification of new deployment sites most suitable to support satellite ocean color missions.

The variability of the backscattering to scattering ratio of marine particles, b bp : b p , is examined from in situ measurements performed during the spring and early summer of 2004 in the eastern English Channel and southern North Sea. This area is characterized by a quasi-permanent background of mineral matter from direct inputs, or resuspension effects, and by relatively intense spring phytoplankton blooms (mainly diatoms and the prymnesiophyte Phaeocystis globosa). The b bp : b p surface values range between 0.0024 and 0.0417, with a mean value of 0.0138 6 0.0083. In order to interpret such a great variability, simultaneous water samples were collected for the biogeochemical characterization of the bulk suspended particle population. We show that the b bp : b p variability is related to the composition of the particulate assemblage expressed by Chl a, the POC : SPM and POC : Chl a ratios, where Chl a, POC, and SPM are the concentrations of chlorophyll a, particulate organic carbon, and suspended particulate matter, respectively. Low b bp : b p values are observed for a particle population dominated by low refractive index material such as phytoplankton, whereas high b bp : b p values are generally observed in presence of relatively high concentration of inorganic particles. The amount of organic material (both living and nonliving, including phytoplankton) relative to phytoplankton has a strong (and sometimes the greatest) effect on the backscattering-to-scattering ratio. Assuming that phytoplankton and detritus have similar refractive index, this pattern is interpreted as resulting from changes in the particle size distribution as well as by aggregation of mineral and nonliving organic detrital material.

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