Determination of the volume scattering function of aqueous particle suspensions with a laboratory multi-angle light scattering instrument

Babin, Marcel; Stramski, Dariusz; Reynolds, Rick A.; Wright, Vanessa; Leymarie, Édouard

doi:10.1364/ao.51.003853

Cited by 19 publications

(21 citation statements)

References 68 publications

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“…To evaluate the performance of the design in terms of shading avoidance, a 3D Monte Carlo code, named SimulO, was used. This code has been previously used to evaluate the performance of optical instrumentations (Leymarie et al, 2010;Babin et al, 2012;Doxaran et al, 2016) but can also serve to perform shading estimation (Gerbi et al, 2016) based on a 3D backward Monte Carlo approach (see section E in the Supplementary Material for details). In this study, a direct sun in a black sky has been used to simulate sky radiances.…”

Section: Shading Estimationmentioning

confidence: 99%

ProVal: A New Autonomous Profiling Float for High Quality Radiometric Measurements

et al. 2018

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An efficient system to produce in situ high quality radiometric measurements is compulsory to rigorously perform the vicarious calibration of satellite sensors dedicated to Ocean Color Radiometry (OCR) and to validate their derived products. This requirement is especially needed during the early stages of an OCR satellite activity or for remote areas poorly covered by oceanographic cruises with possible bio-optical anomalies. Taking advantage of Argo's profiling float technology, we present a new autonomous profiling float dedicated to in situ radiometric measurements. The float is based on the Provor CTS5 (manufacturer NKE) with an added novel two protruding arm design allowing for sensor redundancies, shading mitigation and near-surface data. Equipped with two identical radiometers on each arm that measure downward irradiance and upwelling radiance at seven wavelengths, the ProVal float generates both redundant radiometric profiles as well as an estimate of Remote Sensing Reflectance. Results from 449 profiles obtained in the NW Mediterranean Sea and in the Indian sector of the Southern Ocean are presented to illustrate the ProVal float technical maturity. Analysis of the behavior of the profiling float, including tilting and ascent speeds is presented. The vertical stability of the ProVal exhibits 85% of surface data of the Mediterranean Sea with a tilt smaller than 10 degrees. This percentage is 40% in the Southern Ocean due to rougher seas. Redundant sensors provide a characterization of the relative drift between sensors over the deployment which is found to be <0.15% per month over a year. Post-cruise calibration of a recovered float revealed no significant drift. As an example of the utility of ProVal floats, a match-up of Remote Sensing Reflectance measured with the European Space Agency Ocean and Land Color Imager (OLCI onboard Sentinel-3A) is shown. It follows that profiling floats, such as ProVal, could provide a significant contribution to an upcoming global System Vicarious Calibration of space-based radiometers.

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Section: Shading Estimationmentioning

confidence: 99%

ProVal: A New Autonomous Profiling Float for High Quality Radiometric Measurements

et al. 2018

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“…These measurements were made with a sample placed in a 20 mL cylindrical glass vial. The DAWN-EOS instrument used in this study has been previously characterized and calibrated for such measurement configuration [61]. This instrument uses a diode-pumped frequency-doubled Nd-YAG laser at light wavelength 532 nm with a Gaussian beam profile of 62 µm in diameter.…”

Section: Instrumentationmentioning

confidence: 99%

“…which allows for determination of DoLP(ψ) from Equation (2). The calibration procedure described in Babin et al [61] allows for determination of β(ψ) in absolute units. Importantly, the calibration procedure of DAWN-EOS is fundamentally different from the calibration procedure of LISST-VSF.…”

Section: Instrumentationmentioning

confidence: 99%

Measurements of the Volume Scattering Function and the Degree of Linear Polarization of Light Scattered by Contrasting Natural Assemblages of Marine Particles

2018

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The light scattering properties of seawater play important roles in radiative transfer in the ocean and optically-based methods for characterizing marine suspended particles from in situ and remote sensing measurements. The recently commercialized LISST-VSF instrument is capable of providing in situ or laboratory measurements of the volume scattering function, β p ( ψ ) , and the degree of linear polarization, DoLP p ( ψ ) , associated with particle scattering. These optical quantities of natural particle assemblages have not been measured routinely in past studies. To fully realize the potential of LISST-VSF measurements, we evaluated instrument performance, and developed calibration correction functions from laboratory measurements and Mie scattering calculations for standard polystyrene beads suspended in water. The correction functions were validated with independent measurements. The improved LISST-VSF protocol was applied to measurements of β p ( ψ ) and DoLP p ( ψ ) taken on 17 natural seawater samples from coastal and offshore marine environments characterized by contrasting assemblages of suspended particles. Both β p ( ψ ) and DoLP p ( ψ ) exhibited significant variations related to a broad range of composition and size distribution of particulate assemblages. For example, negative relational trends were observed between the particulate backscattering ratio derived from β p ( ψ ) and increasing proportions of organic particles or phytoplankton in the particulate assemblage. Our results also suggest a potential trend between the maximum values of DoLP p ( ψ ) and particle size metrics, such that a decrease in the maximum DoLP p ( ψ ) tends to be associated with particulate assemblages exhibiting a higher proportion of large-sized particles. Such results have the potential to advance optically-based applications that rely on an understanding of relationships between light scattering and particle properties of natural particulate assemblages.

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“…In the 80s and 90s, measurements on polarized scattering of oceanic waters [12] and of some specific marine species [13][14][15][16][17] were reported. In the last two decades, the advance in modern optical technology led to the development of several prototype VSF instruments [18][19][20][21][22][23][24][25][26]. Lee and Lewis [18] developed a Volume Scattering Meter (VSM) with a periscope-shaped prism measuring the VSF from 0.6°to 177.3°with an angular resolution of 0.3°.…”

Section: Introductionmentioning

confidence: 99%

Calibration of the LISST-VSF to derive the volume scattering functions in clear waters

Zhang

Xiong

et al. 2019

Opt. Express

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The recently commercialized LISST-VSF instrument measures the volume scattering function (VSF) from 0.1°to 15°with a traditional laser diffraction unit (LISST) and from 15°to 155°with an eyeball component. Between these two optical components, only the LISST unit is calibrated. The eyeball measurements are scaled using the VSFs at 15°that are measured by both components. As this relative calibration relies on a valid measurement at 15°by the LISST, it might fail in clear oceanic waters, where the forward scattering is relative weak either due to a lack of large particles or an overall low concentration of all particles. In this study, we calibrated the LISST-VSF eyeball component through a series of lab experiments using standard polystyrene beads. Validation with the beads of two different sizes showed a median difference of 11.1% between theoretical and calibrated values. Further evaluations with in situ data collected by the LISST-VSF and an ECO-BB3 meter indicated that the new calibration worked well in both turbid and clear waters, while the relative calibration method tended to overestimate VSFs in clear waters.

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Determination of the volume scattering function of aqueous particle suspensions with a laboratory multi-angle light scattering instrument

Cited by 19 publications

References 68 publications

ProVal: A New Autonomous Profiling Float for High Quality Radiometric Measurements

ProVal: A New Autonomous Profiling Float for High Quality Radiometric Measurements

Measurements of the Volume Scattering Function and the Degree of Linear Polarization of Light Scattered by Contrasting Natural Assemblages of Marine Particles

Calibration of the LISST-VSF to derive the volume scattering functions in clear waters

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