Physical Sciences and Mathematics | Open Access Articles

Determination Of The Absorption Coefficient Of Chromophoric Dissolved Organic Matter From Underway Spectrophotometry, Giorgio Dall’Olmo, Robert J. W. Brewin, Francesco Nencioli, Emanuele Organelli, Ina Lefering, David Mckee, Rüdiger Röttgers, Catherine Mitchell, Emmanuel Boss, Annick Bricaud, Gavin Tilstone

Marine Sciences Faculty Scholarship

Measurements of the absorption coefficient of chromophoric dissolved organic matter (ay) are needed to validate existing ocean-color algorithms. In the surface open ocean, these measurements are challenging because of low ay values. Yet, existing global datasets demonstrate that ay could contribute between 30% to 50% of the total absorption budget in the 400-450 nm spectral range, thus making accurate measurement of ay essential to constrain these uncertainties. In this study, we present a simple way of determining ay using a commercially-available in-situ spectrophotometer operated in underway mode. The obtained ay values were validated using independent collocated measurements. The method is …

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Two Databases Derived From Bgc-Argo Float Measurements For Marine Biogeochemical And Bio-Optical Applications, Emanuele Organelli, Marie Barbieux, Hervé Claustre, Catherine Schmechtig, Antoine Poteau, Annick Bricaud, Emmanuel Boss, Nathan Briggs, Giorgio Dall'olmo, Fabrizio D'Ortenzio, Edouard Leymarie, Antoine Mangin, Grigor Obolensky, Christophe Penkerc'h, Louis Prieur, Collin Roesler, Romain Serra, Julia Uitz, Xiaogang Xing

Marine Sciences Faculty Scholarship

Since 2012, an array of 105 Biogeochemical-Argo (BGC-Argo) floats has been deployed across the world's oceans to assist in filling observational gaps that are required for characterizing open-ocean environments. Profiles of biogeochemical (chlorophyll and dissolved organic matter) and optical (single-wavelength particulate optical backscattering, downward irradiance at three wavelengths, and photosynthetically available radiation) variables are collected in the upper 1000 m every 1 to 10 days. The database of 9837 vertical profiles collected up to January 2016 is presented and its spatial and temporal coverage is discussed. Each variable is quality controlled with specifically developed procedures and its time series is …

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Simplified Model Of Spectral Absorption By Non-Algal Particles And Dissolved Organic Materials In Aquatic Environments, B. B. Cael, Emmanuel Boss

Marine Sciences Faculty Scholarship

© 2017 Optical Society of America. Absorption by non-algal particles (NAP, ad) and colored dissolved organic matter (CDOM, ag) are frequently modeled by exponential functions of wavelength, either separately or as a sum. We present a new representation of NAP-plus-CDOM absorption adg based on the stretched exponential function adg(λ) = Aexp{−[s(λ − λo)]β}, whose parameter β can be considered a measure of optical heterogeneity. A double exponential representation of adg can be fit extremely well by a stretched exponential for all plausible parameter combinations, despite having one fewer free parameter than a double exponential. Fitting two published compilations of in …

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Pan-Arctic Optical Characteristics Of Colored Dissolved Organic Matter: Tracing Dissolved Organic Carbon In Changing Arctic Waters Using Satellite Ocean Color Data, Atsushi Matsuoka, Emmanuel Boss, Marcel Babin, Lee Karp-Boss, Mark Hafez, Alex Chekalyuk, Christopher W. Proctor, P. Jeremy Werdell, Annick Bricaud

Marine Sciences Faculty Scholarship

Light absorption of the colored fraction of dissolved organic matter (CDOM) is a dominant optical component of the Arctic Ocean (AO). Here we show Pan-Arctic characteristics of CDOM light absorption for various Arctic regions covering both coastal and oceanic waters during the Tara Oceans Polar Circle expedition. The Siberian (or eastern) side of the AO is characterized by higher CDOM absorption values compared to the North American (or western) side. This is due to the difference in watersheds between the eastern and western sides of the AO and is consistent with an Arctic absorption database recently built by Matsuoka et …

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Recommendations For Obtaining Unbiased Chlorophyll Estimates From In Situ Chlorophyll Fluorometers: A Global Analysis Of Wet Labs Eco Sensors, Collin Roesler, Julia Uitz, Hervé Claustre, Emmanuel Boss, Xiaogang Xing, Emanuele Organelli, Nathan Briggs, Annick Bricaud, Catherine Schmechtig, Antoine Poteau, Fabrizio D'Ortenzio, Josephine Ras, Susan Drapeau, Nils Haëntjens, Marie Barbieux

Marine Sciences Faculty Scholarship

Chlorophyll fluorometers provide the largest in situ global data set for estimating phytoplankton biomass because of their ease of use, size, power consumption, and relatively low price. While in situ chlorophyll a (Chl) fluorescence is proxy for Chl a concentration, and hence phytoplankton biomass, there exist large natural variations in the relationship between in situ fluorescence and extracted Chl a concentration. Despite this large natural variability, we present here a global validation data set for the WET Labs Environmental Characterization Optics (ECO) series chlorophyll fluorometers that suggests a factor of 2 overestimation in the factory calibrated Chl a estimates for …

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Analytical Solution Of The Nitracline With The Evolution Of Subsurface Chlorophyll Maximum In Stratified Water Columns, Xiang Gong, Wensheng Jiang, Linhui Wang, Huiwang Gao, Emmanuel Boss, Xiaohong Yao, Shuh Ji Kao, Jie Shi

Marine Sciences Faculty Scholarship

In a stratified water column, the nitracline is a layer where the nitrate concentration increases below the nutrient-depleted upper layer, exhibiting a strong vertical gradient in the euphotic zone. The subsurface chlorophyll maximum layer (SCML) forms near the bottom of the euphotic zone, acting as a trap to diminish the upward nutrient supply. Depth and steepness of the nitracline are important measurable parameters related to the vertical transport of nitrate into the euphotic zone. The correlation between the SCML and the nitracline has been widely reported in the literature, but the analytic solution for the relationship between them is not …

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Vector Radiative Transfer Model For Coupled Atmosphere And Ocean Systems Including Inelastic Sources In Ocean Waters, Peng Wang Zhai, Yongxiang Hu, David M. Winker, Bryan A. Franz, Jeremy Werdell, Emmanuel Boss

Marine Sciences Faculty Scholarship

Inelastic scattering plays an important role in ocean optics. The main inelastic scattering mechanisms include Raman scattering, fluorescence by colored dissolved organic matter (FDOM), and fluorescence by chlorophyll. This paper reports an implementation of all three inelastic scattering mechanisms in the exact vector radiative transfer model for coupled atmosphere and ocean Systems (CAOS). Simulation shows that FDOM contributes to the water radiation field in the broad visible spectral region, while chlorophyll fluorescence is limited in a narrow band centered at 685 nm. This is consistent with previous findings in the literature. The fluorescence distribution as a function of depth and …

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Marine Sciences Faculty Scholarship

Marine Sciences Faculty Scholarship

Simplified Model Of Spectral Absorption By Non-Algal Particles And Dissolved Organic Materials In Aquatic Environments, B. B. Cael, Emmanuel Boss

Marine Sciences Faculty Scholarship

Marine Sciences Faculty Scholarship

Marine Sciences Faculty Scholarship

Analytical Solution Of The Nitracline With The Evolution Of Subsurface Chlorophyll Maximum In Stratified Water Columns, Xiang Gong, Wensheng Jiang, Linhui Wang, Huiwang Gao, Emmanuel Boss, Xiaohong Yao, Shuh Ji Kao, Jie Shi

Marine Sciences Faculty Scholarship

Vector Radiative Transfer Model For Coupled Atmosphere And Ocean Systems Including Inelastic Sources In Ocean Waters, Peng Wang Zhai, Yongxiang Hu, David M. Winker, Bryan A. Franz, Jeremy Werdell, Emmanuel Boss

Marine Sciences Faculty Scholarship