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A Global Compilation Of In Situ Aquatic High Spectral Resolution Inherent And Apparent Optical Property Data For Remote Sensing Applications, Kimberly A. Casey, Cecile S. Rousseaux, Watson W. Gregg, Emmanuel Boss, Alison P. Chase, Susanne E. Craig, Colleen B. Mouw, Rick A. Reynolds, Dariusz Stramski, Steven G. Ackleson, Annick Bricaud, Blake Schaeffer, Marlon R. Lewis, Stéphane Maritorena
A Global Compilation Of In Situ Aquatic High Spectral Resolution Inherent And Apparent Optical Property Data For Remote Sensing Applications, Kimberly A. Casey, Cecile S. Rousseaux, Watson W. Gregg, Emmanuel Boss, Alison P. Chase, Susanne E. Craig, Colleen B. Mouw, Rick A. Reynolds, Dariusz Stramski, Steven G. Ackleson, Annick Bricaud, Blake Schaeffer, Marlon R. Lewis, Stéphane Maritorena
Marine Sciences Faculty Scholarship
Light emerging from natural water bodies and measured by radiometers contains information about the local type and concentrations of phytoplankton, non-algal particles and colored dissolved organic matter in the underlying waters. An increase in spectral resolution in forthcoming satellite and airborne remote sensing missions is expected to lead to new or improved capabilities for characterizing aquatic ecosystems. Such upcoming missions include NASA's Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission; the NASA Surface Biology and Geology designated observable mission; and NASA Airborne Visible/Infrared Imaging Spectrometer - Next Generation (AVIRIS-NG) airborne missions. In anticipation of these missions, we present an organized dataset …
Information Content Of Absorption Spectra And Implications For Ocean Color Inversion, B. B. Cael, Alison Chase, Emmanuel Boss
Information Content Of Absorption Spectra And Implications For Ocean Color Inversion, B. B. Cael, Alison Chase, Emmanuel Boss
Marine Sciences Faculty Scholarship
The increasing use of hyperspectral optical data in oceanography, both in situ and via remote sensing, holds the potential to significantly advance characterization of marine ecology and biogeochemistry because, in principle, hyperspectral data can provide much more detailed inferences of ecosystem properties via inversion. Effective inferences, however, require careful consideration of the close similarity of different signals of interest, and how these interplay with measurement error and uncertainty to reduce the degrees of freedom (DoF) of hyperspectral measurements. Here we discuss complementary approaches to quantify the DoF in hyperspectral measurements in the case of in situ particulate absorption measurements, though …
Tara Pacific Expedition's Atmospheric Measurements Of Marine Aerosols Across The Atlantic And Pacific Oceans: Overview And Preliminary Results, J. M. Flores, G. Bourdin, G. Bourdin, O. Altaratz, M. Trainic, N. Lang-Yona, E. Dzimban, S. Steinau, F. Tettich, S. Planes, S. Planes, D. Allemand, S. Agostini, B. Banaigs, E. Boissin, E. Boss, E. Douville, D. Forcioli, P. Furla, P. E. Galand, P. E. Galand, M. B. Sullivan, M. B. Sullivan, Gilson, Gilson, F. Lombard, F. Lombard, C. Moulin, S. Pesant, J. Poulain, J. Poulain
Tara Pacific Expedition's Atmospheric Measurements Of Marine Aerosols Across The Atlantic And Pacific Oceans: Overview And Preliminary Results, J. M. Flores, G. Bourdin, G. Bourdin, O. Altaratz, M. Trainic, N. Lang-Yona, E. Dzimban, S. Steinau, F. Tettich, S. Planes, S. Planes, D. Allemand, S. Agostini, B. Banaigs, E. Boissin, E. Boss, E. Douville, D. Forcioli, P. Furla, P. E. Galand, P. E. Galand, M. B. Sullivan, M. B. Sullivan, Gilson, Gilson, F. Lombard, F. Lombard, C. Moulin, S. Pesant, J. Poulain, J. Poulain
Marine Sciences Faculty Scholarship
Marine aerosols play a significant role in the global radiative budget, in clouds' processes, and in the chemistry of the marine atmosphere. There is a critical need to better understand their production mechanisms, composition, chemical properties, and the contribution of ocean-derived biogenic matter to their mass and number concentration. Here we present an overview of a new dataset of in situ measurements of marine aerosols conducted over the 2.5-yr Tara Pacific Expedition over 110, 000 km across the Atlantic and Pacific Oceans. Preliminary results are presented here to describe the new dataset that will be built using this novel set …
Evaluation Of Diagnostic Pigments To Estimate Phytoplankton Size Classes, Alison P. Chase, Sasha J. Kramer, Nils Haëntjens, Emmanuel S. Boss, Lee Karp-Boss, Mimi Edmondson, Jason R. Graff
Evaluation Of Diagnostic Pigments To Estimate Phytoplankton Size Classes, Alison P. Chase, Sasha J. Kramer, Nils Haëntjens, Emmanuel S. Boss, Lee Karp-Boss, Mimi Edmondson, Jason R. Graff
Marine Sciences Faculty Scholarship
Limnology and Oceanography: Methods published by Wiley Periodicals LLC. on behalf of Association for the Sciences of Limnology and Oceanography. Phytoplankton accessory pigments are commonly used to estimate phytoplankton size classes, particularly during development and validation of biogeochemical models and satellite ocean color-based algorithms. The diagnostic pigment analysis (DPA) is based on bulk measurements of pigment concentrations and relies on assumptions regarding the presence of specific pigments in different phytoplankton taxonomic groups. Three size classes are defined by the DPA: picoplankton, nanoplankton, and microplankton. Until now, the DPA has not been evaluated against an independent approach that provides phytoplankton size …
Algorithm To Derive Inherent Optical Properties From Remote Sensing Reflectance In Turbid And Eutrophic Lakes, Kun Xue, Emmanuel Boss, Ronghua Ma, Ming Shen
Algorithm To Derive Inherent Optical Properties From Remote Sensing Reflectance In Turbid And Eutrophic Lakes, Kun Xue, Emmanuel Boss, Ronghua Ma, Ming Shen
Marine Sciences Faculty Scholarship
Inherent optical properties play an important role in understanding the biogeochemical processes of lakes by providing proxies for a variety of biogeochemical quantities, including phytoplankton pigments. However, to date, it has been difficult to accurately derive the absorption coefficient of phytoplankton [aph(λ)] in turbid and eutrophic waters from remote sensing. A large dataset of remote sensing of reflectance [ Rrs (λ)] and absorption coefficients was measured for samples collected from lakes in the middle and lower reaches of the Yangtze River and Huai River basin (MLYHR), China. In the process of scattering correction of spectrophotometric measurements, the particulate absorption coefficients …
Evaluating Satellite Estimates Of Particulate Backscatter In The Global Open Ocean Using Autonomous Profiling Floats, K. M. Bisson, E. Boss, T. K. Westberry, M. J. Behrenfeld
Evaluating Satellite Estimates Of Particulate Backscatter In The Global Open Ocean Using Autonomous Profiling Floats, K. M. Bisson, E. Boss, T. K. Westberry, M. J. Behrenfeld
Marine Sciences Faculty Scholarship
Satellite retrievals of particulate backscattering (bbp) are widely used in studies of ocean ecology and biogeochemistry, but have been historically difficult to validate due to the paucity of available ship-based comparative field measurements. Here we present a comparison of satellite and in situ bbp using observations from autonomous floats (n = 2,486 total matchups across three satellites), which provide bbp at 700 nm. With these data, we quantify how well the three inversion products currently distributed by NASA ocean color retrieve bbp. We find that the median ratio of satellite derived bbp to float bbp ranges from 0.77 to 1.60 …
The Plankton, Aerosol, Cloud, Ocean Ecosystem Mission Status, Science, Advances, P. Jeremy Werdell, Michael J. Behrenfeld, Paula S. Bontempi, Emmanuel Boss, Brian Cairns, Gary T. Davis, Bryan A. Franz, Ulrik B. Gliese, Eric T. Gorman, Otto Hasekamp, Kirk D. Knobelspiesse, Antonio Mannino, J. Vanderlei Martins, Charlesr Mcclain, Gerhard Meister, Lorraine A. Remer
The Plankton, Aerosol, Cloud, Ocean Ecosystem Mission Status, Science, Advances, P. Jeremy Werdell, Michael J. Behrenfeld, Paula S. Bontempi, Emmanuel Boss, Brian Cairns, Gary T. Davis, Bryan A. Franz, Ulrik B. Gliese, Eric T. Gorman, Otto Hasekamp, Kirk D. Knobelspiesse, Antonio Mannino, J. Vanderlei Martins, Charlesr Mcclain, Gerhard Meister, Lorraine A. Remer
Marine Sciences Faculty Scholarship
The Plankton, Aerosol, Cloud, Ocean Ecosystem (PACE) mission represents the National Aeronautics and Space Administration's (NASA) next investment in satellite ocean color and the study of Earth's ocean-atmosphere system, enabling new insights into oceanographic and atmospheric responses to Earth's changing climate. PACE objectives include extending systematic cloud, aerosol, and ocean biological and biogeochemical data records, making essential ocean color measurements to further understand marine carbon cycles, food-web processes, and ecosystem responses to a changing climate, and improving knowledge of how aerosols influence ocean ecosystems and, conversely, how ocean ecosystems and photochemical processes affect the atmosphere. PACE objectives also encompass management …
Radiative Transfer Modeling Of Phytoplankton Fluorescence Quenching Processes, Peng Wang Zhai, Emmanuel Boss, Bryan Franz, P. Jeremy Werdell, Yongxiang Hu
Radiative Transfer Modeling Of Phytoplankton Fluorescence Quenching Processes, Peng Wang Zhai, Emmanuel Boss, Bryan Franz, P. Jeremy Werdell, Yongxiang Hu
Marine Sciences Faculty Scholarship
We report the first radiative transfer model that is able to simulate phytoplankton fluorescence with both photochemical and non-photochemical quenching included. The fluorescence source term in the inelastic radiative transfer equation is proportional to both the quantum yield and scalar irradiance at excitation wavelengths. The photochemical and nonphotochemical quenching processes change the quantum yield based on the photosynthetic active radiation. A sensitivity study was performed to demonstrate the dependence of the fluorescence signal on chlorophyll a concentration, aerosol optical depths and solar zenith angles. This work enables us to better model the phytoplankton fluorescence, which can be used in the …
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
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 …
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
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 …
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
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 …
Spectral Attenuation And Backscattering As Indicators Of Average Particle Size, Wayne Homer Slade, Emmanuel Boss
Spectral Attenuation And Backscattering As Indicators Of Average Particle Size, Wayne Homer Slade, Emmanuel Boss
Marine Sciences Faculty Scholarship
Measurements of the particulate beam attenuation coefficient at multiple wavelengths in the ocean typically exhibit a power law dependence on wavelength, and the slope of that power law has been related to the slope of the particle size distribution (PSD), when assumed to be a power law function of particle size. Recently, spectral backscattering coefficient measurements have been made using sensors deployed at moored observatories, on autonomous underwater vehicles, and even retrieved from space-based measurements of remote sensing reflectance. It has been suggested that these backscattering measurements may also be used to obtain information about the shape of the PSD. …
Significance Of Scattering By Oceanic Particles At Angles Around 120 Degree, Xiaodong Zhang, Emmanuel Boss, Deric J. Gray
Significance Of Scattering By Oceanic Particles At Angles Around 120 Degree, Xiaodong Zhang, Emmanuel Boss, Deric J. Gray
Marine Sciences Faculty Scholarship
Field observations and theoretical studies have shown that shapes of the volume scattering functions (VSFs) of oceanic particles in the backward directions, i.e., VSFs normalized by the total backscattering coefficient, exhibit a surprisingly low variability at angles near 120 degree, which is also confirmed by measurements of VSFs in coastal waters around the US. To investigate what this minimum variability angle (θ∗) represents, we estimated mean values of the VSFs in the backward angles using four mean value theorems: mean value for integral, weighted mean value for integral, classic mean value for differentiation and Cauchy's mean value. We also estimated …
Retrieving Marine Inherent Optical Properties From Satellites Using Temperature And Salinitydependent Backscattering By Seawater, P. Jeremy Werdell, Bryan A. Franz, Jason T. Lefler, Wayne D. Robinson, Emmanuel Boss
Retrieving Marine Inherent Optical Properties From Satellites Using Temperature And Salinitydependent Backscattering By Seawater, P. Jeremy Werdell, Bryan A. Franz, Jason T. Lefler, Wayne D. Robinson, Emmanuel Boss
Marine Sciences Faculty Scholarship
Time-series of marine inherent optical properties (IOPs) from ocean color satellite instruments provide valuable data records for studying long-term time changes in ocean ecosystems. Semi-Analytical algorithms (SAAs) provide a common method for estimating IOPs from radiometric measurements of the marine light field. Most SAAs assign constant spectral values for seawater absorption and backscattering, assume spectral shape functions of the remaining constituent absorption and scattering components (e.g., phytoplankton, non-Algal particles, and colored dissolved organic matter), and retrieve the magnitudes of each remaining constituent required to match the spectral distribution of measured radiances. Here, we explore the use of temperature- and salinity-dependent …
Method For Estimating Mean Particle Size From High-Frequency Fluctuations In Beam Attenuation Or Scattering Measurements, Nathan T. Briggs, Wayne H. Slade, Emmanuel Boss, Mary Jane Perry
Method For Estimating Mean Particle Size From High-Frequency Fluctuations In Beam Attenuation Or Scattering Measurements, Nathan T. Briggs, Wayne H. Slade, Emmanuel Boss, Mary Jane Perry
Marine Sciences Faculty Scholarship
The ability to estimate mean particle size using simple, low-power optical instruments promises to greatly expand coverage of particle size measurements in the ocean and advance understanding of myriad processes from sediment transport to biological carbon sequestration. Here we present a method for estimating the mean diameter of particles in suspension from high-resolution time series of simple optical measurements, such as beam attenuation or optical backscattering. Validation results from a laboratory clay aggregation experiment show a good fit with independent mean particle diameter estimates in the 10-80 μm diameter range, with relative biases of 17%-38% and relative root mean square …
Autonomous, High-Resolution Observations Of Particle Flux In The Oligotrophic Ocean, M. L. Estapa, K. Buesseler, E. Boss, G. Gerbi
Autonomous, High-Resolution Observations Of Particle Flux In The Oligotrophic Ocean, M. L. Estapa, K. Buesseler, E. Boss, G. Gerbi
Marine Sciences Faculty Scholarship
Observational gaps limit our understanding of particle flux attenuation through the upper mesopelagic because available measurements (sediment traps and radiochemical tracers) have limited temporal resolution, are labor-intensive, and require ship support. Here, we conceptually evaluate an autonomous, optical proxy-based method for high-resolution observations of particle flux. We present four continuous records of particle flux collected with autonomous profiling floats in the western Sargasso Sea and the subtropical North Pacific, as well as one shorter record of depth-resolved particle flux near the Bermuda Atlantic Time-series Study (BATS) and Oceanic Flux Program (OFP) sites. These observations illustrate strong variability in particle flux …
Influence Of Raman Scattering On Ocean Color Inversion Models, Toby K. Westberry, Emmanuel Boss, Zhongping Lee
Influence Of Raman Scattering On Ocean Color Inversion Models, Toby K. Westberry, Emmanuel Boss, Zhongping Lee
Marine Sciences Faculty Scholarship
Raman scattering can be a significant contributor to the emergent radiance spectrum from the surface ocean. Here, we present an analytical approach to directly estimate the Raman contribution to remote sensing reflectance, and evaluate its effects on optical properties estimated from two common semi analytical inversion models. For application of the method to ocean color remote sensing, spectral irradiance products in the ultraviolet from the OMI instrument are merged with MODerate-resolution Imaging Spectroradiometer (MODIS) data in the visible. The resulting global fields of Raman-corrected optical properties show significant differences from standard retrievals, particularly for the particulate backscattering coefficient, bbp, where …
Generalized Ocean Color Inversion Model For Retrieving Marine Inherent Optical Properties, P. Jeremy Werdell, Bryan A. Franz, Sean W. Bailey, Gene C. Feldman, Emmanuel Boss, Vittorio E. Brando, Mark Dowell, Takafumi Hirata, Samantha J. Lavender, Zhong Ping Lee, Hubert Loisel, Stéphane Maritorena, Fréderic Mélin, Timothy S. Moore, Timothy J. Smyth, David Antoine, Emmanuel Devred, Odile Hembise Fanton D'Andon, Antoine Mangin
Generalized Ocean Color Inversion Model For Retrieving Marine Inherent Optical Properties, P. Jeremy Werdell, Bryan A. Franz, Sean W. Bailey, Gene C. Feldman, Emmanuel Boss, Vittorio E. Brando, Mark Dowell, Takafumi Hirata, Samantha J. Lavender, Zhong Ping Lee, Hubert Loisel, Stéphane Maritorena, Fréderic Mélin, Timothy S. Moore, Timothy J. Smyth, David Antoine, Emmanuel Devred, Odile Hembise Fanton D'Andon, Antoine Mangin
Marine Sciences Faculty Scholarship
Ocean color measured from satellites provides daily, global estimates of marine inherent optical properties (IOPs). Semi-analytical algorithms (SAAs) provide one mechanism for inverting the color of the water observed by the satellite into IOPs. While numerous SAAs exist, most are similarly constructed and few are appropriately parameterized for all water masses for all seasons. To initiate community-wide discussion of these limitations, NASA organized two workshops that deconstructed SAAs to identify similarities and uniqueness and to progress toward consensus on a unified SAA. This effort resulted in the development of the generalized IOP (GIOP) model software that allows for the construction …
Remote Identification Of The Invasive Tunicate Didemnum Vexillum Using Reflectance Spectroscopy, Thomas Leeuw, Seth O. Newburg, Emmanuel S. Boss, Wayne H. Slade, Michael G. Soroka, Judith Pederson, Chryssostomos Chryssostomidis, Franz S. Hover
Remote Identification Of The Invasive Tunicate Didemnum Vexillum Using Reflectance Spectroscopy, Thomas Leeuw, Seth O. Newburg, Emmanuel S. Boss, Wayne H. Slade, Michael G. Soroka, Judith Pederson, Chryssostomos Chryssostomidis, Franz S. Hover
Marine Sciences Faculty Scholarship
Benthic coverage of the invasive tunicate Didemnum vexillum on Georges Bank is largely unknown. Monitoring of D. vexillum coverage is vital to understanding the impact this invasive species will have on the productive fishing grounds of Georges Bank. Here we investigate using reflectance spectroscopy as a method for remote identification of D. vexillum. Using two different systems, a NightSea Dive-Spec and a combination of LED light sources with a hyperspectral radiometer, we collected in-situ measurements of reflectance from D. vexillum colonies. In comparison to reflectance spectra of other common benthic substrates, D. vexillum appears to have a unique spectral signature …
Improved Irradiances For Use In Ocean Heating, Primary Production, And Photo-Oxidation Calculations, Curtis D. Mobley, Emmanuel S. Boss
Improved Irradiances For Use In Ocean Heating, Primary Production, And Photo-Oxidation Calculations, Curtis D. Mobley, Emmanuel S. Boss
Marine Sciences Faculty Scholarship
Accurate calculation of underwater light is fundamental to predictions of upper-ocean heating, primary production, and photo-oxidation. However, most ocean models simulating these processes do not yet incorporate radiative transfer modules for their light calculations. Such models are often driven by abovesurface, broadband, daily averaged irradiance or photosynthetically available radiation (PAR) values obtained from climatology or satellite observations, sometimes without correction for sea-surface reflectance, even though surface reflectance can reduce in-water values by more than 20%. We present factors computed by a radiative transfer code that can be used to convert above-surface values in either energy or quantum units to in-water …
Inferring Phytoplankton Carbon And Eco-Physiological Rates From Diel Cycles Of Spectral Particulate Beam-Attenuation Coefficient, G. Dall'olmo, E. Boss, M. J. Behrenfeld, T. K. Westberry, C. Courties, L. Prieur, M. Pujo-Pay, N. Hardman-Mountford, T. Moutin
Inferring Phytoplankton Carbon And Eco-Physiological Rates From Diel Cycles Of Spectral Particulate Beam-Attenuation Coefficient, G. Dall'olmo, E. Boss, M. J. Behrenfeld, T. K. Westberry, C. Courties, L. Prieur, M. Pujo-Pay, N. Hardman-Mountford, T. Moutin
Marine Sciences Faculty Scholarship
The diurnal fluctuations in solar irradiance impose a fundamental frequency on ocean biogeochemistry. Observations of the ocean carbon cycle at these frequencies are rare, but could be considerably expanded by measuring and interpreting the inherent optical properties. A method is presented to analyze diel cycles in particulate beam-attenuation coefficient (cp) measured at multiple wavelengths. The method is based on fitting observations with a size-structured population model coupled to an optical model to infer the particle size distribution and physiologically relevant parameters of the cells responsible for the measured diel cycle in cp. Results show that the information related to size …
Evaluation Of A Compact Sensor For Backscattering And Absorption, Alina Gainusa Bogdan, Emmanuel S. Boss
Evaluation Of A Compact Sensor For Backscattering And Absorption, Alina Gainusa Bogdan, Emmanuel S. Boss
Marine Sciences Faculty Scholarship
Seawater inherent optical properties (IOPs) are key parameters in a wide range of applications in environmental studies and oceanographic research. In particular, the absorption coefficient (a) is the typical IOP used to obtain the concentration of chlorophyll-a in the water-a critical parameter in biological oceanography studies and the backscattering coefficient (bb) is used as a measure of turbidity. In this study, we test a novel instrument concept designed to obtain both the absorption and backscattering coefficients. The instrument would emit a collimated monochromatic light beam into the water retrieving the backscattered light intensity as a function of distance from the …
Estimating The Maritime Component Of Aerosol Optical Depth And Its Dependency On Surface Wind Speed Using Satellite Data, Y. Lehahn, I. Koren, E. Boss, Y. Ben-Ami, O. Altaratz
Estimating The Maritime Component Of Aerosol Optical Depth And Its Dependency On Surface Wind Speed Using Satellite Data, Y. Lehahn, I. Koren, E. Boss, Y. Ben-Ami, O. Altaratz
Marine Sciences Faculty Scholarship
Six years (2003-2008) of satellite measurements of aerosol parameters from the Moderate Resolution Imaging Spectroradiometer (MODIS) and surface wind speeds from Quick Scatterometer (QuikSCAT), the Advanced Microwave Scanning Radiometer (AMSR-E), and the Special Sensor Microwave Imager (SSM/I), are used to provide a comprehensive perspective on the link between surface wind speed and marine aerosol optical depth over tropical and subtropical oceanic regions. A systematic comparison between the satellite derived fields in these regions allows to: (i) separate the relative contribution of wind-induced marine aerosol to the aerosol optical depth; (ii) extract an empirical linear equation linking coarse marine aerosol optical …
Three Years Of Ocean Data From A Bio-Optical Profiling Float, Emmanuel Boss, Mary Jane Perry, Dana Swift, Lisa Taylor, Peter Brickley, J. Ron V. Zaneveld, Stephen Riser
Three Years Of Ocean Data From A Bio-Optical Profiling Float, Emmanuel Boss, Mary Jane Perry, Dana Swift, Lisa Taylor, Peter Brickley, J. Ron V. Zaneveld, Stephen Riser
Marine Sciences Faculty Scholarship
Ocean color, first measured from space 30 years ago, has provided a revolutionary synoptic view of near-surface fields of phytoplankton pigments. Since 1979, a number of ocean color satellite missions have provided coverage of phytoplankton biomass and other biogeochemical variables on scales of days to years and of kilometers to ocean basin. Because of the nature of visible light and its interaction with absorbing and scattering materials in the ocean and atmosphere, these measurements are biased toward nearsurface waters and are obscured by clouds. As a consequence, ocean color satellites miss significant fractions of phytoplankton biomass, marine primary productivity, and …
Spectral Variability Of The Particulate Backscattering Ratio, A. L. Whitmire, E. Boss, T. J. Cowles, W. S. Pegau
Spectral Variability Of The Particulate Backscattering Ratio, A. L. Whitmire, E. Boss, T. J. Cowles, W. S. Pegau
Marine Sciences Faculty Scholarship
The spectral dependency of the particulate backscattering ratio is relevant in the fields of ocean color inversion, light field modeling, and inferring particle properties from optical measurements. Aside from theoretical predictions for spherical, homogeneous particles, we have very limited knowledge of the actual in situ spectral variability of the particulate backscattering ratio. This work presents results from five research cruises that were conducted over a three-year period. Water column profiles of physical and optical properties were conducted across diverse aquatic environments that offered a wide range of particle populations. The main objective of this research was to examine the behavior …
Calibrated Near-Forward Volume Scattering Function Obtained From The Lisst Particle Sizer, Wayne H. Slade, Emmanuel S. Boss
Calibrated Near-Forward Volume Scattering Function Obtained From The Lisst Particle Sizer, Wayne H. Slade, Emmanuel S. Boss
Marine Sciences Faculty Scholarship
The physical nature of particles, such as size, shape, and composition govern their angular light scattering, which is described by the volume scattering function (VSF). Despite the fact that the VSF is one of the most important inherent optical properties, it has rarely been measured in aquatic environments since no commercial instrument exists to measure the full VSF in the field. The commonly used LISST (Laser In Situ Scattering and Transmissometry) particle sizer (Sequoia Scientific, http://www.sequoiasci.com) measures near-forward angular scattering of a laser source (λ = 670 nm) at 32 logarithmically-spaced photodetectors arranged between 0.08 and 15 degrees and inverts …
Theoretical Derivation Of The Depth Average Of Remotely Sensed Optical Parameters, J. Ronald V. Zaneveld, Andrew H. Barnard, Emmanuel Boss
Theoretical Derivation Of The Depth Average Of Remotely Sensed Optical Parameters, J. Ronald V. Zaneveld, Andrew H. Barnard, Emmanuel Boss
Marine Sciences Faculty Scholarship
The dependence of the reflectance at the surface on the vertical structure of optical parameters is derived from first principles. It is shown that the depth dependence is a function of the derivative of the round trip attenuation of the downwelling and backscattered light. Previously the depth dependence was usually modeled as being dependent on the round trip attenuation. Using the new relationship one can calculate the contribution of the mixed layer to the overall reflectance at the surface. This allows one to determine whether or not to ignore the vertical structure at greater depth. It is shown that the …
The Role Of Seawater Constituents In Light Backscattering In The Ocean, Dariusz Stramski, Emmanuel Boss, Darek Bogucki, Kenneth J. Voss
The Role Of Seawater Constituents In Light Backscattering In The Ocean, Dariusz Stramski, Emmanuel Boss, Darek Bogucki, Kenneth J. Voss
Marine Sciences Faculty Scholarship
The significance of light backscattering in the ocean is wide ranging, especially in optical remote sensing. However, the complexity of natural seawater as an optical medium often obscures the measured optical signals to the point that our present-day interpretation and detailed understanding of major sources of backscattering and its variability in the ocean are uncertain and controversial. Here we review the roles played by various seawater constituents in light backscattering and we address a question of 'missing' backscattering. Historically, this question has resulted from a hypothesis that under non-bloom conditions in the open ocean, phytoplankton make a significantly smaller contribution …