1
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Josset D, Cayula S, Concannon B, Sova S, Weidemann A. On the bubble-bubbleless ocean continuum and its meaning for the LiDAR equation: LiDAR measurement of underwater bubble properties during storm conditions. OPTICS EXPRESS 2024; 32:20881-20903. [PMID: 38859458 DOI: 10.1364/oe.515936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 05/06/2024] [Indexed: 06/12/2024]
Abstract
This paper presents the NRL shipboard LiDAR and the first LiDAR dataset of underwater bubbles. The meaning of these LiDAR observations, the algorithms used and their current limitations are discussed. The derivation of the LiDAR multiple scattering regime is derived from the LiDAR observations and theory. The detection of the underwater bubble presence and their depth is straightforward to estimate from the depolarized laser return. This dataset strongly suggest that the whitecaps term in the LiDAR equation formalism needs to be revisited. The retrieval of the fraction of air volume within a given volume of water (void fraction) is possible and the algorithm is stable with a simple ocean backscatter LiDAR system. The accuracy of the void fraction retrieval will increase significantly with future developments.
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2
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Villermaux E, Wang X, Deike L. Bubbles spray aerosols: Certitudes and mysteries. PNAS NEXUS 2022; 1:pgac261. [PMID: 36712328 PMCID: PMC9809165 DOI: 10.1093/pnasnexus/pgac261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 11/23/2022] [Indexed: 11/27/2022]
Abstract
Ocean spray aerosol formed by bubble bursting are at the core of a broad range of atmospheric processes: they are efficient cloud condensation nuclei and carry a variety of chemical, biological, and biomass material from the surface of the ocean to the atmosphere. The origin and composition of these aerosols is sensibly controlled by the detailed fluid mechanics of bubble bursting. This perspective summarizes our present-day knowledge on how bursting bubbles at the surface of a liquid pool contribute to its fragmentation, namely to the formation of droplets stripped from the pool, and associated mechanisms. In particular, we describe bounds and yields for each distinct mechanism, and the way they are sensitive to the bubble production and environmental conditions. We also underline the consequences of each mechanism on some of the many air-sea interactions phenomena identified to date. Attention is specifically payed at delimiting the known from the unknown and the certitudes from the speculations.
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Affiliation(s)
| | - Xiaofei Wang
- Department of Environmental Science and Engineering, Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Fudan University, Shanghai 200433, China
| | - Luc Deike
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA,High Meadows Environmental Institute, Princeton University, Princeton, NJ 08544, USA
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3
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Viana RD, Lorenzzetti JA, Carvalho JT, Nunziata F. Estimating Energy Dissipation Rate from Breaking Waves Using Polarimetric SAR Images. SENSORS 2020; 20:s20226540. [PMID: 33207621 PMCID: PMC7697822 DOI: 10.3390/s20226540] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 11/09/2020] [Accepted: 11/13/2020] [Indexed: 11/24/2022]
Abstract
The total energy dissipation rate on the ocean surface, ϵt (W m−2), provides a first-order estimation of the kinetic energy input rate at the ocean–atmosphere interface. Studies on the spatial and temporal distribution of the energy dissipation rate are important for the improvement of climate and wave models. Traditional oceanographic research normally uses remote measurements (airborne and platforms sensors) and in situ data acquisition to estimate ϵt; however, those methods cover small areas over time and are difficult to reproduce especially in the open oceans. Satellite remote sensing has proven the potential to estimate some parameters related to breaking waves on a synoptic scale, including the energy dissipation rate. In this paper, we use polarimetric Synthetic Aperture Radar (SAR) data to estimate ϵt under different wind and sea conditions. The used methodology consisted of decomposing the backscatter SAR return in terms of two contributions: a polarized contribution, associated with the fast response of the local wind (Bragg backscattering), and a non-polarized (NP) contribution, associated with wave breaking (Non-Bragg backscattering). Wind and wave parameters were estimated from the NP contribution and used to calculate ϵt from a parametric model dependent of these parameters. The results were analyzed using wave model outputs (WAVEWATCH III) and previous measurements documented in the literature. For the prevailing wind seas conditions, the ϵt estimated from pol-SAR data showed good agreement with dissipation associated with breaking waves when compared to numerical simulations. Under prevailing swell conditions, the total energy dissipation rate was higher than expected. The methodology adopted proved to be satisfactory to estimate the total energy dissipation rate for light to moderate wind conditions (winds below 10 m s−1), an environmental condition for which the current SAR polarimetric methods do not estimate ϵt properly.
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Affiliation(s)
- Rafael D. Viana
- Earth Observation and Geoinformatics Division, National Institute for Space Research (OTG/INPE), São José dos Campos 12201-970, SP, Brazil;
| | - João A. Lorenzzetti
- Earth Observation and Geoinformatics Division, National Institute for Space Research (OTG/INPE), São José dos Campos 12201-970, SP, Brazil;
- Correspondence: ; Tel.: +55-12-99719-2511
| | - Jonas T. Carvalho
- Laboratory of Ocean and Atmosphere Studies (LOA), Earth Observation and Geoinformatics Division, National Institute for Space Research (OTG/INPE), São José dos Campos 12201-970, SP, Brazil;
| | - Ferdinando Nunziata
- Dipartimento di Ingegneria, Universitá degli Studi di Napoli Parthenope, 80143 Napoli, Italy;
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4
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NewApproach to Predict the Motion Characteristics of Single Bubbles in Still Water. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9193981] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Under the action of gravity, buoyancy, and surface tension, bubbles generated by wave breaking will rupture and polymerize, causing the occurrence of high-speed jets and strong turbulence in nearby water bodies, which in turn affects sea–air exchange, sediment transport, and pollutant movement. These interactions are closely related to the shape and velocity changes in single bubbles. Therefore, understanding the motion characteristics of single bubbles is essential. In this research, a large number of experiments were carried out to serve this purpose. The experimental data were used to develop three machine learning models for the bubble final velocity, bubble drag coefficient, and bubble shape, respectively. The performance of the feed forward back propagation neural network (FBNN) models for the final velocity and drag coefficient were evaluated. The coefficient of determination (R2) and root mean squared error (RMSE) value of final velocity prediction model was recorded at 0.83 and 0.0518, respectively. Meanwhile, for the drag coefficient prediction model, the values are 0.92 for R2 and 0.1534 for RMSE. The models can provide a more accurate output if compared to that from the empirical formulas. K-nearest neighbours (KNN), logistic regression, and random forest were applied as the algorithm while developing the bubble shape classification model. The best performance is achieved by the logistic regression.
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5
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Frouin RJ, Franz BA, Ibrahim A, Knobelspiesse K, Ahmad Z, Cairns B, Chowdhary J, Dierssen HM, Tan J, Dubovik O, Huang X, Davis AB, Kalashnikova O, Thompson DR, Remer LA, Boss E, Coddington O, Deschamps PY, Gao BC, Gross L, Hasekamp O, Omar A, Pelletier B, Ramon D, Steinmetz F, Zhai PW. Atmospheric Correction of Satellite Ocean-Color Imagery During the PACE Era. FRONTIERS IN EARTH SCIENCE 2019; 7:10.3389/feart.2019.00145. [PMID: 32440515 PMCID: PMC7241613 DOI: 10.3389/feart.2019.00145] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission will carry into space the Ocean Color Instrument (OCI), a spectrometer measuring at 5nm spectral resolution in the ultraviolet (UV) to near infrared (NIR) with additional spectral bands in the shortwave infrared (SWIR), and two multi-angle polarimeters that will overlap the OCI spectral range and spatial coverage, i. e., the Spectrometer for Planetary Exploration (SPEXone) and the Hyper-Angular Rainbow Polarimeter (HARP2). These instruments, especially when used in synergy, have great potential for improving estimates of water reflectance in the post Earth Observing System (EOS) era. Extending the top-of-atmosphere (TOA) observations to the UV, where aerosol absorption is effective, adding spectral bands in the SWIR, where even the most turbid waters are black and sensitivity to the aerosol coarse mode is higher than at shorter wavelengths, and measuring in the oxygen A-band to estimate aerosol altitude will enable greater accuracy in atmospheric correction for ocean color science. The multi-angular and polarized measurements, sensitive to aerosol properties (e.g., size distribution, index of refraction), can further help to identify or constrain the aerosol model, or to retrieve directly water reflectance. Algorithms that exploit the new capabilities are presented, and their ability to improve accuracy is discussed. They embrace a modern, adapted heritage two-step algorithm and alternative schemes (deterministic, statistical) that aim at inverting the TOA signal in a single step. These schemes, by the nature of their construction, their robustness, their generalization properties, and their ability to associate uncertainties, are expected to become the new standard in the future. A strategy for atmospheric correction is presented that ensures continuity and consistency with past and present ocean-color missions while enabling full exploitation of the new dimensions and possibilities. Despite the major improvements anticipated with the PACE instruments, gaps/issues remain to be filled/tackled. They include dealing properly with whitecaps, taking into account Earth-curvature effects, correcting for adjacency effects, accounting for the coupling between scattering and absorption, modeling accurately water reflectance, and acquiring a sufficiently representative dataset of water reflectance in the UV to SWIR. Dedicated efforts, experimental and theoretical, are in order to gather the necessary information and rectify inadequacies. Ideas and solutions are put forward to address the unresolved issues. Thanks to its design and characteristics, the PACE mission will mark the beginning of a new era of unprecedented accuracy in ocean-color radiometry from space.
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Affiliation(s)
- Robert J. Frouin
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, United States
- Correspondence: Robert J. Frouin,
| | - Bryan A. Franz
- Ocean Ecology Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, United States
| | - Amir Ibrahim
- Ocean Ecology Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, United States
- Science Systems and Applications Inc., Lanham, MD, United States
| | - Kirk Knobelspiesse
- Ocean Ecology Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, United States
| | - Ziauddin Ahmad
- Ocean Ecology Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, United States
- Science Application International Corporation, McLean, VA, United States
| | - Brian Cairns
- NASA Goddard Institute for Space Studies, New York, NY, United States
| | - Jacek Chowdhary
- NASA Goddard Institute for Space Studies, New York, NY, United States
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, United States
| | - Heidi M. Dierssen
- Department of Marine Sciences, University of Connecticut, Groton, CT, United States
| | - Jing Tan
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, United States
| | - Oleg Dubovik
- Laboratoire d’Optique Atmosphérique, Université de Lille, Villeneuve d’Ascq, France
| | - Xin Huang
- Laboratoire d’Optique Atmosphérique, Université de Lille, Villeneuve d’Ascq, France
| | - Anthony B. Davis
- Jet Propulsion Laboratory, California Institute of Technology Pasadena, CA, United States
| | - Olga Kalashnikova
- Jet Propulsion Laboratory, California Institute of Technology Pasadena, CA, United States
| | - David R. Thompson
- Jet Propulsion Laboratory, California Institute of Technology Pasadena, CA, United States
| | - Lorraine A. Remer
- Joint Center for Earth System Technology, University of Maryland Baltimore County, Baltimore, MD, United States
| | - Emmanuel Boss
- School of Marine Sciences, University of Maine, Orono, ME, United States
| | - Odele Coddington
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO, United States
| | | | - Bo-Cai Gao
- Naval Research Laboratory, Washington, DC, United States
| | | | - Otto Hasekamp
- Earth Science Group, Netherlands Institute for Space Research, Utrecht, Netherlands
| | - Ali Omar
- Atmospheric Composition Branch, NASA Langley Research Center, Hampton, VA, United States
| | - Bruno Pelletier
- Institut de Recherche Mathématique, Université de Rennes, Rennes, Franc
| | | | | | - Peng-Wang Zhai
- Department of Physics, University of Maryland Baltimore County, Baltimore, MD, United States
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6
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Balch WM. The Ecology, Biogeochemistry, and Optical Properties of Coccolithophores. ANNUAL REVIEW OF MARINE SCIENCE 2018; 10:71-98. [PMID: 29298138 DOI: 10.1146/annurev-marine-121916-063319] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Coccolithophores are major contributors to phytoplankton communities and ocean biogeochemistry and are strong modulators of the optical field in the sea. New discoveries are changing paradigms about these calcifiers. A new role for silicon in coccolithophore calcification is coupling carbonate and silicon cycles. Phosphorus and iron play key roles in regulating coccolithophore growth. Comparing molecular phylogenies with coccolith morphometrics is forcing the reconciliation of biological and geological observations. Mixotrophy may be a possible life strategy for deep-dwelling species, which has ramifications for biological pump and alkalinity pump paradigms. Climate, ocean temperatures, and pH appear to be affecting coccolithophores in unexpected ways. Global calcification is approximately 1-3% of primary productivity and affects CO2 budgets. New measurements of the backscattering cross section of coccolithophores have improved satellite-based algorithms and their application in case I and case II optical waters. Remote sensing has allowed the detection of basin-scale coccolithophore features in the Southern Ocean.
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Affiliation(s)
- William M Balch
- Bigelow Laboratory for Ocean Sciences, East Boothbay, Maine 04544, USA;
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7
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Bubble Clouds in Coastal Waters and Their Role in Air-Water Gas Exchange of CO2. JOURNAL OF MARINE SCIENCE AND ENGINEERING 2015. [DOI: 10.3390/jmse3030866] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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8
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Liang JH, McWilliams JC, Sullivan PP, Baschek B. Large eddy simulation of the bubbly ocean: New insights on subsurface bubble distribution and bubble-mediated gas transfer. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jc007766] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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9
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Twardowski M, Zhang X, Vagle S, Sullivan J, Freeman S, Czerski H, You Y, Bi L, Kattawar G. The optical volume scattering function in a surf zone inverted to derive sediment and bubble particle subpopulations. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jc007347] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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10
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Czerski H, Twardowski M, Zhang X, Vagle S. Resolving size distributions of bubbles with radii less than 30
μ
m with optical and acoustical methods. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011jc007177] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- H. Czerski
- Institute of Sound and Vibration Research University of Southampton Southampton UK
| | - M. Twardowski
- Department of Research WET Labs, Inc. Narragansett Rhode Island USA
| | - X. Zhang
- Department of Earth System Science and Policy University of North Dakota Grand Forks North Dakota USA
| | - S. Vagle
- Institute of Ocean Sciences, Fisheries and Oceans Canada Sidney, British Columbia Canada
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11
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Ma G, Shi F, Kirby JT. A polydisperse two-fluid model for surf zone bubble simulation. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jc006667] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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12
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Liang JH, McWilliams JC, Sullivan PP, Baschek B. Modeling bubbles and dissolved gases in the ocean. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jc006579] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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13
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Vagle S, McNeil C, Steiner N. Upper ocean bubble measurements from the NE Pacific and estimates of their role in air-sea gas transfer of the weakly soluble gases nitrogen and oxygen. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009jc005990] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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14
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Abstract
The lidar signature from a collection of bubbles is proportional to the volume backscatter coefficient at a scattering angle of 180 degrees . This quantity, calculated using a combination of geometric optics and diffraction, is proportional to the void fraction of the bubbles in the water for any bubble size distribution. The constant of proportionality is 233 m(-1) sr(-1)for clean bubbles, slightly less for bubbles coated with a thin layer of organic material, and as large as 1445 m(-1) sr(-1) for a thick coating of protein.
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Affiliation(s)
- James H Churnside
- Earth System Research Laboratory, National Oceanic and Atmospheric Administration, 325 Broadway, Boulder, CO 80305, USA.
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15
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Piskozub J, Stramski D, Terrill E, Melville WK. Small-scale effects of underwater bubble clouds on ocean reflectance: 3-D modeling results. OPTICS EXPRESS 2009; 17:11747-11752. [PMID: 19582089 DOI: 10.1364/oe.17.011747] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We examined the effect of individual bubble clouds on remote-sensing reflectance of the ocean with a 3-D Monte Carlo model of radiative transfer. The concentrations and size distribution of bubbles were defined based on acoustical measurements of bubbles in the surface ocean. The light scattering properties of bubbles for various void fractions were calculated using Mie scattering theory. We show how the spatial pattern, magnitude, and spectral behavior of remote-sensing reflectance produced by modeled bubble clouds change due to variations in their geometric and optical properties as well as the background optical properties of the ambient water. We also determined that for realistic sizes of bubble clouds, a plane-parallel horizontally homogeneous geometry (1-D radiative transfer model) is inadequate for modeling water-leaving radiance above the cloud.
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Affiliation(s)
- Jacek Piskozub
- Institute of Oceanology, Polish Academy of Sciences, Powstancow Warszawy 55, 81-712 Sopot, Poland.
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16
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Loisel H, Nicolas JM, Sciandra A, Stramski D, Poteau A. Spectral dependency of optical backscattering by marine particles from satellite remote sensing of the global ocean. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2005jc003367] [Citation(s) in RCA: 136] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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17
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Leifer I, Caulliez G, de Leeuw G. Bubbles generated from wind-steepened breaking waves: 2. Bubble plumes, bubbles, and wave characteristics. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2004jc002676] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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18
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Reid JS, Brooks B, Crahan KK, Hegg DA, Eck TF, O'Neill N, de Leeuw G, Reid EA, Anderson KD. Reconciliation of coarse mode sea-salt aerosol particle size measurements and parameterizations at a subtropical ocean receptor site. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2005jd006200] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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19
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Mezzenga R, Schurtenberger P, Burbidge A, Michel M. Understanding foods as soft materials. NATURE MATERIALS 2005; 4:729-40. [PMID: 16195765 DOI: 10.1038/nmat1496] [Citation(s) in RCA: 439] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Foods make up some of the most complex examples of soft condensed matter (SCM) with which we interact daily. Their complexity arises from several factors: the intricacy of components, the different aggregation states in which foods are encountered, and the multitude of relevant characteristic time and length scales. Because foodstuffs are governed by the rules of SCM physics but with all the complications related to real systems, the experimental and theoretical approaches of SCM physics have deepened our comprehension of their nature and behaviour, but many questions remain. In this review we discuss the current understanding of food science, by considering established SCM methods as well as emerging techniques and theoretical approaches. With their complexity, heterogeneity and multitude of states, foods provide SCM physics with a challenge of remarkable importance.
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Affiliation(s)
- Raffaele Mezzenga
- Department of Physics, University of Fribourg, Perolles, Fribourg, CH-1700 Switzerland.
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20
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Piskozub J, Stramski D, Terrill E, Melville WK. Influence of forward and multiple light scatter on the measurement of beam attenuation in highly scattering marine environments. APPLIED OPTICS 2004; 43:4723-4731. [PMID: 15352398 DOI: 10.1364/ao.43.004723] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Using three-dimensional Monte Carlo radiative transfer simulations, we examine the effect of beam transmissometer geometry on the relative error in the measurement of the beam-attenuation coefficient in an aquatic environment characterized by intense light scattering, especially within submerged bubble clouds entrained by surface-wave breaking. We discuss the forward-scattering error associated with the detection of photons scattered at small angles (< 1 degrees) and the multiple-scattering error associated with the detection of photons scattered more than once along the path length of the instrument. Several scattering phase functions describing bubble clouds at different bubble void fractions in the water are considered. Owing to forward-scattering error, a beam-attenuation meter (beam transmissometer) with a half-angle of receiver acceptance of 1.0 degrees and a path length of 0.1 m can underestimate the true beam attenuation within the bubble cloud by more than 50%. For bubble clouds with a beam attenuation of as much as 100 m(-1), the multiple-scattering error is no more than a few percent. These results are compared with simulations for some example phase functions that are representative of other scattering regimes found in natural waters. The forward-scattering error for the Petzold phase function of turbid waters is 16% for a typical instrument geometry, whereas for the Henyey-Greenstein phase function with the asymmetry parameter of 0.7 and 0.9 the error range is 8-28%.
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Affiliation(s)
- Jacek Piskozub
- Institute of Oceanography, Polish Academy of Sciences, Powstańców Warszawy 55, Sopot 81-712, Poland.
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21
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Zhang X, Lewis M, Bissett WP, Johnson B, Kohler D. Optical influence of ship wakes. APPLIED OPTICS 2004; 43:3122-3132. [PMID: 15176201 DOI: 10.1364/ao.43.003122] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The optical variations observed within ship wakes are largely due to the generation of copious amounts of air bubbles in the upper ocean, a fraction of which accumulate as foam at the surface, where they release scavenged surfactants. Field experiments were conducted to test previous theoretical predictions of the variations in optical properties that result from bubble injection in the surface ocean. Variations in remote-sensing reflectance and size distribution of bubbles within the ship-wake zone were determined in three different optical water types: the clear equatorial Pacific Ocean, moderately turbid coastal waters, and very turbid coastal waters, the latter two of which were offshore of New Jersey. Bubbles introduced by moving vessels increased the backscattering in all cases, which in turn enhanced the reflectance over the entire visible and infrared wave bands. The elevated reflectance had different spectral characteristics in the three locations. The color of ship wakes appears greener in the open ocean, whereas little change in color was observed in near-coastal turbid waters, consistent with predictions. Colorless themselves, bubbles increase the reflected radiance and change the color of the ocean in a way that depends on the spectral backscattering and absorption of the undisturbed background waters. For remote observation from aircraft or satellite, the foam and added surfactants further enhance the reflectance to a degree dependent on the illumination and the viewing geometry.
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Affiliation(s)
- Xiaodong Zhang
- Earth System Science Institute, University of North Dakota, Grand Forks, North Dakota 58202-9007, USA.
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22
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Green RE, Sosik HM. Analysis of apparent optical properties and ocean color models using measurements of seawater constituents in New England continental shelf surface waters. ACTA ACUST UNITED AC 2004. [DOI: 10.1029/2003jc001977] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Rebecca E. Green
- Biology Department; Woods Hole Oceanographic Institution; Woods Hole Massachusetts USA
| | - Heidi M. Sosik
- Biology Department; Woods Hole Oceanographic Institution; Woods Hole Massachusetts USA
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23
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Stramska M. Observations of oceanic whitecaps in the north polar waters of the Atlantic. ACTA ACUST UNITED AC 2003. [DOI: 10.1029/2002jc001321] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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24
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Reul N. A model of sea-foam thickness distribution for passive microwave remote sensing applications. ACTA ACUST UNITED AC 2003. [DOI: 10.1029/2003jc001887] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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25
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Abstract
Surface waves play an important role in the exchange of mass, momentum and energy between the atmosphere and the ocean. The development of the wave field depends on wind, wave-wave and wave-current interactions and wave dissipation owing to breaking, which is accompanied by momentum fluxes from waves to currents. Wave breaking supports air-sea fluxes of heat and gas, which have a profound effect on weather and climate. But wave breaking is poorly quantified and understood. Here we present measurements of wave breaking, using aerial imaging and analysis, and provide a statistical description of related sea-surface processes. We find that the distribution of the length of breaking fronts per unit area of sea surface is proportional to the cube of the wind speed and that, within the measured range of the speed of the wave fronts, the length of breaking fronts per unit area is an exponential function of the speed of the front. We also find that the fraction of the ocean surface mixed by breaking waves, which is important for air-sea exchange, is dominated by wave breaking at low velocities and short wavelengths.
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Affiliation(s)
- W Kendall Melville
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093-0213, USA.
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26
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Yan B, Chen B, Stamnes K. Role of oceanic air bubbles in atmospheric correction of ocean color imagery. APPLIED OPTICS 2002; 41:2202-2212. [PMID: 12003211 DOI: 10.1364/ao.41.002202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Ocean color is the radiance that emanates from the ocean because of scattering by chlorophyll pigments and particles of organic and inorganic origin. Air bubbles in the ocean also scatter light and thus contribute to the water-leaving radiance. This additional water-leaving radiance that is due to oceanic air bubbles could violate the black pixel assumption at near-infrared wavelengths and be attributed to chlorophyll in the visible. Hence, the accuracy of the atmospheric correction required for the retrieval of ocean color from satellite measurements is impaired. A comprehensive radiative transfer code for the coupled atmosphere--ocean system is employed to assess the effect of oceanic air bubbles on atmospheric correction of ocean color imagery. This effect is found to depend on the wavelength-dependent optical properties of oceanic air bubbles as well as atmospheric aerosols.
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Affiliation(s)
- Banghua Yan
- Geophysical Institute, University of Alaska Fairbanks, 99775-7320, USA.
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