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Gerrit De Leeuw - One of the best experts on this subject based on the ideXlab platform.
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Characteristics of Bubble Plumes, Bubble-Plume Bubbles, and Waves from Wind-Steepened Wave-Breaking
Journal of Marine Systems, 2007Co-Authors: Ira Leifer, Guillemette Caulliez, Gerrit De LeeuwAbstract:Observations of breaking waves, associated bubble Plumes and bubble-plume size distributions were used to explore the coupled evolution of wave-breaking, wave properties and bubble-plume characteristics. Experiments were made in a large, freshwater, wind-wave channel with mechanical wind-steepened waves and a wind speed of 13 m s- 1. Bubble Plumes exhibited a wide range of bubble distributions, physical extent and dynamics. A classification scheme was developed based on plume extent and "optical density" which is the ability of a plume to optically obscure the image of the background until maximum penetration of the plume. Plumes were classified as either dense (obscure) or diffuse (no-obscure). For each class, the plume bubble population size distribution, Φ(r,t), where r is the bubble radius and t the time, was determined. Dense Plumes have a large radius peak in Φ and thus are enhanced in large bubbles. Diffuse Plumes are well-described by a weakly size decreasing Φ(r,t) for r 1000 μm. The bubble-plume formation rate, P, for each class, wave-breaking rate and wave characteristics were measured with respect to fetch. Wave-breaking rate and intensity are strongly fetch-dependent. In general, the trends in P and wave breaking are similar, reaching a maximum at the fetch of maximum wave breaking. The ratio of P for dense to diffuse Plumes is even more sensitive to the occurrence of the most intense wave breaking, where dense plume formation is the greatest. Using P and the bubble size population distributions for each plume class, the global bubble-plume, injection size distribution, Ψi(r), was calculated. The volume injection rate for the study area was 640 cm3 s- 1 divided approximately equally between bubbles smaller and larger than r ∼ 1700 μm. © 2006 Elsevier B.V. All rights reserved.
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Characteristics of Bubble Plumes, Bubble-Plume Bubbles, and Waves from Wind-Steepened Wave-Breaking
Journal of Marine Systems, 2007Co-Authors: Ira Leifer, Guillemette Caulliez, Gerrit De LeeuwAbstract:Observations of breaking waves, associated bubble Plumes and bubble-plume size distributions were used to explore the coupled evolution of wave-breaking, wave properties and bubble-plume characteristics. Experiments were made in a large, freshwater, wind-wave channel with mechanical wind-steepened waves and a wind speed of 13 m s-1. Bubble Plumes exhibited a wide range of bubble distributions, physical extent and dynamics. A classification scheme was developed based on plume extent and “optical density” which is the ability of a plume to optically obscure the image of the background until maximum penetration of the plume. Plumes were classified as either dense (obscure) or diffuse (no-obscure). For each class, the plume bubble population size distribution, Φ(r,t), where r is the bubble radius and t the time, was determined. Dense Plumes have a large radius peak in Φ and thus are enhanced in large bubbles. Diffuse Plumes are well-described by a weakly size decreasing Φ(r,t) for rb1000 μm and a more strongly size decreasing Φ(r,t) for rN1000 μm. The bubble-plume formation rate, P, for each class, wave-breaking rate and wave characteristics were measured with respect to fetch. Wave-breaking rate and intensity are strongly fetch-dependent. In general, the trends in P and wave breaking are similar, reaching a maximum at the fetch of maximum wave breaking. The ratio of P for dense to diffuse Plumes is even more sensitive to the occurrence of the most intense wave breaking, where dense plume formation is the greatest. Using P and the bubble size population distributions for each plume class, the global bubble-plume, injection size distribution, i(r), was calculated. The volume injection rate for the study area was 640 cm3 s-1 divided approximately equally between bubbles smaller and larger than r∼1700 μm.
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Characteristics of bubble Plumes, bubble-plume bubbles and waves from wind-steepened wave breaking
Journal of Marine Systems, 2007Co-Authors: Ira Leifer, Guillemette Caulliez, Gerrit De LeeuwAbstract:International audienceObservations of breaking waves, associated bubble Plumes and bubble-plume size distributions were used to explore the coupled evolution of wave-breaking, wave properties and bubble-plume characteristics. Experiments were made in a large, freshwater, wind-wave channel with mechanical wind-steepened waves and a wind speed of 13 m s-1. Bubble Plumes exhibited a wide range of bubble distributions, physical extent and dynamics. A classification scheme was developed based on plume extent and “optical density” which is the ability of a plume to optically obscure the image of the background until maximum penetration of the plume. Plumes were classified as either dense (obscure) or diffuse (no-obscure). For each class, the plume bubble population size distribution, Φ(r,t), where r is the bubble radius and t the time, was determined. Dense Plumes have a large radius peak in Φ and thus are enhanced in large bubbles. Diffuse Plumes are well-described by a weakly size decreasing Φ(r,t) for rb1000 μm and a more strongly size decreasing Φ(r,t) for rN1000 μm. The bubble-plume formation rate, P, for each class, wave-breaking rate and wave characteristics were measured with respect to fetch. Wave-breaking rate and intensity are strongly fetch-dependent. In general, the trends in P and wave breaking are similar, reaching a maximum at the fetch of maximum wave breaking. The ratio of P for dense to diffuse Plumes is even more sensitive to the occurrence of the most intense wave breaking, where dense plume formation is the greatest. Using P and the bubble size population distributions for each plume class, the global bubble-plume, injection size distribution, i(r), was calculated. The volume injection rate for the study area was 640 cm3 s-1 divided approximately equally between bubbles smaller and larger than r∼1700 μm
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Dense Bubble Plumes, Wave Breaking, and Air-Water Gas Exchange
2006Co-Authors: Ira Leifer, Guillemette Caulliez, Gerrit De LeeuwAbstract:Bubble-plume characteristics including the population size-distribution, F, plume formation rate, P, and wave-characteristics were measured for mechanical, wind-steepened wave breaking in a large, fresh-water wind-wave channel for 13 m s-1 wind speed. Bubble Plumes showed a wide diversity of F, physical extent, and dynamics, which were used to develop a classification scheme. The coupled evolution of wavebreaking, wave-properties, and bubble-plume characteristics were investigated. A significant differentiation amongst Plumes was some Plumes' ability to obscure optically (termed dense) the image background. Dense Plumes (as opposed to diffuse Plumes) were found to contain a large radius, r, peak in F - i.e., dense Plumes are enhanced in large bubbles. Population is the total number of bubbles in the plume. Diffuse Plumes are well-described by a shallowly decreasing F(r), for r < 1000 μm, and a more strongly decreasing F(r) for r > 1000 μm. For each class, P was determined and compared with the measured wave-breaking rate and wave characteristics with respect to fetch. The wave-breaking rate and intensity were strongly fetch dependent. In general, the trends in P and wave breaking are similar, reaching a maximum at the fetch of maximum wave breaking. The ratio of P for dense to diffuse Plumes is even more sensitive to the occurrence of the most intense wave breaking, where dense plume formation is the greatest. Using P and the bubble-size population distributions for each plume class, the global bubble-plume, injection size-distribution, Yi(r), was calculated and decreased as r-1.2, for r < 1700 μm and Yi ~ r-3.9 for larger r. The volume injection rate for the study area was 640 cm3 s-1 divided approximately equally between bubbles smaller and larger than r ~ 1700-μm. The significance of dense versus diffuse Plumes with respect to gas exchange of significant atmospheric gases was tested with a numerical bubble model and demonstrated that the large bubbles in dense Plumes plays a very significant roll in the overall bubble-mediated air-water gas exchange, including the dependency of gas exchange on solubility and Schmidt number.
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Bubbles Generated from Wind-Steepened Breaking Waves: Part 2. Bubble Plumes, Bubbles, and Wave Characteristics
Journal of Geophysical Research. Oceans, 2006Co-Authors: Ira Leifer, Guillemette Caulliez, Gerrit De LeeuwAbstract:Measurements of breaking-wave generated bubble Plumes were made in fresh (but not clean) water in a large wind-wave tunnel. To preserve diversity, a classification scheme was developed. based on plume dimensions and “optical density,” or the plume's ability to obscure the background. Optically dense Plumes were due to the presence of a peak at large radius in the plume bubble size-distribution. For each class, the plume formation rate, P, was measured at different fetches. The relationship between wave-breaking characteristics and the bubble-plume evolution is examined in detail for these experiments. The wave-breaking rate and intensity were strongly fetch dependent as the mechanically-steepened wind-waves rapidly evolved with fetch due to wind, dissipation, and non-linear wave-wave interactions. P followed the trend in wave breaking, reaching a maximum at the fetch of maximum wave breaking. The ratio of dense to diffuse Plumes was more sensitive to the wave-breaking intensity. Using P and the bubble population size-distributions for each class, the global bubble-plume, injection distribution, Yi(r), where r is radius, was calculated. Yi decreased as Yi~r-1.2, for r < 1700 µm and Yi~r-3.9 for larger r. Total volume injection was 640 cm3 s-1; divided approximately equally between bubbles smaller and larger than 1700-µm radius. Using plume volumes at maximum penetration for each class, a concentration distribution was calculated and showed plume concentrations greater than the background population by one to several orders of magnitude depending upon r.
Ira Leifer - One of the best experts on this subject based on the ideXlab platform.
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Characteristics of Bubble Plumes, Bubble-Plume Bubbles, and Waves from Wind-Steepened Wave-Breaking
Journal of Marine Systems, 2007Co-Authors: Ira Leifer, Guillemette Caulliez, Gerrit De LeeuwAbstract:Observations of breaking waves, associated bubble Plumes and bubble-plume size distributions were used to explore the coupled evolution of wave-breaking, wave properties and bubble-plume characteristics. Experiments were made in a large, freshwater, wind-wave channel with mechanical wind-steepened waves and a wind speed of 13 m s- 1. Bubble Plumes exhibited a wide range of bubble distributions, physical extent and dynamics. A classification scheme was developed based on plume extent and "optical density" which is the ability of a plume to optically obscure the image of the background until maximum penetration of the plume. Plumes were classified as either dense (obscure) or diffuse (no-obscure). For each class, the plume bubble population size distribution, Φ(r,t), where r is the bubble radius and t the time, was determined. Dense Plumes have a large radius peak in Φ and thus are enhanced in large bubbles. Diffuse Plumes are well-described by a weakly size decreasing Φ(r,t) for r 1000 μm. The bubble-plume formation rate, P, for each class, wave-breaking rate and wave characteristics were measured with respect to fetch. Wave-breaking rate and intensity are strongly fetch-dependent. In general, the trends in P and wave breaking are similar, reaching a maximum at the fetch of maximum wave breaking. The ratio of P for dense to diffuse Plumes is even more sensitive to the occurrence of the most intense wave breaking, where dense plume formation is the greatest. Using P and the bubble size population distributions for each plume class, the global bubble-plume, injection size distribution, Ψi(r), was calculated. The volume injection rate for the study area was 640 cm3 s- 1 divided approximately equally between bubbles smaller and larger than r ∼ 1700 μm. © 2006 Elsevier B.V. All rights reserved.
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Characteristics of Bubble Plumes, Bubble-Plume Bubbles, and Waves from Wind-Steepened Wave-Breaking
Journal of Marine Systems, 2007Co-Authors: Ira Leifer, Guillemette Caulliez, Gerrit De LeeuwAbstract:Observations of breaking waves, associated bubble Plumes and bubble-plume size distributions were used to explore the coupled evolution of wave-breaking, wave properties and bubble-plume characteristics. Experiments were made in a large, freshwater, wind-wave channel with mechanical wind-steepened waves and a wind speed of 13 m s-1. Bubble Plumes exhibited a wide range of bubble distributions, physical extent and dynamics. A classification scheme was developed based on plume extent and “optical density” which is the ability of a plume to optically obscure the image of the background until maximum penetration of the plume. Plumes were classified as either dense (obscure) or diffuse (no-obscure). For each class, the plume bubble population size distribution, Φ(r,t), where r is the bubble radius and t the time, was determined. Dense Plumes have a large radius peak in Φ and thus are enhanced in large bubbles. Diffuse Plumes are well-described by a weakly size decreasing Φ(r,t) for rb1000 μm and a more strongly size decreasing Φ(r,t) for rN1000 μm. The bubble-plume formation rate, P, for each class, wave-breaking rate and wave characteristics were measured with respect to fetch. Wave-breaking rate and intensity are strongly fetch-dependent. In general, the trends in P and wave breaking are similar, reaching a maximum at the fetch of maximum wave breaking. The ratio of P for dense to diffuse Plumes is even more sensitive to the occurrence of the most intense wave breaking, where dense plume formation is the greatest. Using P and the bubble size population distributions for each plume class, the global bubble-plume, injection size distribution, i(r), was calculated. The volume injection rate for the study area was 640 cm3 s-1 divided approximately equally between bubbles smaller and larger than r∼1700 μm.
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Characteristics of bubble Plumes, bubble-plume bubbles and waves from wind-steepened wave breaking
Journal of Marine Systems, 2007Co-Authors: Ira Leifer, Guillemette Caulliez, Gerrit De LeeuwAbstract:International audienceObservations of breaking waves, associated bubble Plumes and bubble-plume size distributions were used to explore the coupled evolution of wave-breaking, wave properties and bubble-plume characteristics. Experiments were made in a large, freshwater, wind-wave channel with mechanical wind-steepened waves and a wind speed of 13 m s-1. Bubble Plumes exhibited a wide range of bubble distributions, physical extent and dynamics. A classification scheme was developed based on plume extent and “optical density” which is the ability of a plume to optically obscure the image of the background until maximum penetration of the plume. Plumes were classified as either dense (obscure) or diffuse (no-obscure). For each class, the plume bubble population size distribution, Φ(r,t), where r is the bubble radius and t the time, was determined. Dense Plumes have a large radius peak in Φ and thus are enhanced in large bubbles. Diffuse Plumes are well-described by a weakly size decreasing Φ(r,t) for rb1000 μm and a more strongly size decreasing Φ(r,t) for rN1000 μm. The bubble-plume formation rate, P, for each class, wave-breaking rate and wave characteristics were measured with respect to fetch. Wave-breaking rate and intensity are strongly fetch-dependent. In general, the trends in P and wave breaking are similar, reaching a maximum at the fetch of maximum wave breaking. The ratio of P for dense to diffuse Plumes is even more sensitive to the occurrence of the most intense wave breaking, where dense plume formation is the greatest. Using P and the bubble size population distributions for each plume class, the global bubble-plume, injection size distribution, i(r), was calculated. The volume injection rate for the study area was 640 cm3 s-1 divided approximately equally between bubbles smaller and larger than r∼1700 μm
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Dense Bubble Plumes, Wave Breaking, and Air-Water Gas Exchange
2006Co-Authors: Ira Leifer, Guillemette Caulliez, Gerrit De LeeuwAbstract:Bubble-plume characteristics including the population size-distribution, F, plume formation rate, P, and wave-characteristics were measured for mechanical, wind-steepened wave breaking in a large, fresh-water wind-wave channel for 13 m s-1 wind speed. Bubble Plumes showed a wide diversity of F, physical extent, and dynamics, which were used to develop a classification scheme. The coupled evolution of wavebreaking, wave-properties, and bubble-plume characteristics were investigated. A significant differentiation amongst Plumes was some Plumes' ability to obscure optically (termed dense) the image background. Dense Plumes (as opposed to diffuse Plumes) were found to contain a large radius, r, peak in F - i.e., dense Plumes are enhanced in large bubbles. Population is the total number of bubbles in the plume. Diffuse Plumes are well-described by a shallowly decreasing F(r), for r < 1000 μm, and a more strongly decreasing F(r) for r > 1000 μm. For each class, P was determined and compared with the measured wave-breaking rate and wave characteristics with respect to fetch. The wave-breaking rate and intensity were strongly fetch dependent. In general, the trends in P and wave breaking are similar, reaching a maximum at the fetch of maximum wave breaking. The ratio of P for dense to diffuse Plumes is even more sensitive to the occurrence of the most intense wave breaking, where dense plume formation is the greatest. Using P and the bubble-size population distributions for each plume class, the global bubble-plume, injection size-distribution, Yi(r), was calculated and decreased as r-1.2, for r < 1700 μm and Yi ~ r-3.9 for larger r. The volume injection rate for the study area was 640 cm3 s-1 divided approximately equally between bubbles smaller and larger than r ~ 1700-μm. The significance of dense versus diffuse Plumes with respect to gas exchange of significant atmospheric gases was tested with a numerical bubble model and demonstrated that the large bubbles in dense Plumes plays a very significant roll in the overall bubble-mediated air-water gas exchange, including the dependency of gas exchange on solubility and Schmidt number.
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Bubbles Generated from Wind-Steepened Breaking Waves: Part 2. Bubble Plumes, Bubbles, and Wave Characteristics
Journal of Geophysical Research. Oceans, 2006Co-Authors: Ira Leifer, Guillemette Caulliez, Gerrit De LeeuwAbstract:Measurements of breaking-wave generated bubble Plumes were made in fresh (but not clean) water in a large wind-wave tunnel. To preserve diversity, a classification scheme was developed. based on plume dimensions and “optical density,” or the plume's ability to obscure the background. Optically dense Plumes were due to the presence of a peak at large radius in the plume bubble size-distribution. For each class, the plume formation rate, P, was measured at different fetches. The relationship between wave-breaking characteristics and the bubble-plume evolution is examined in detail for these experiments. The wave-breaking rate and intensity were strongly fetch dependent as the mechanically-steepened wind-waves rapidly evolved with fetch due to wind, dissipation, and non-linear wave-wave interactions. P followed the trend in wave breaking, reaching a maximum at the fetch of maximum wave breaking. The ratio of dense to diffuse Plumes was more sensitive to the wave-breaking intensity. Using P and the bubble population size-distributions for each class, the global bubble-plume, injection distribution, Yi(r), where r is radius, was calculated. Yi decreased as Yi~r-1.2, for r < 1700 µm and Yi~r-3.9 for larger r. Total volume injection was 640 cm3 s-1; divided approximately equally between bubbles smaller and larger than 1700-µm radius. Using plume volumes at maximum penetration for each class, a concentration distribution was calculated and showed plume concentrations greater than the background population by one to several orders of magnitude depending upon r.
Guillemette Caulliez - One of the best experts on this subject based on the ideXlab platform.
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Characteristics of Bubble Plumes, Bubble-Plume Bubbles, and Waves from Wind-Steepened Wave-Breaking
Journal of Marine Systems, 2007Co-Authors: Ira Leifer, Guillemette Caulliez, Gerrit De LeeuwAbstract:Observations of breaking waves, associated bubble Plumes and bubble-plume size distributions were used to explore the coupled evolution of wave-breaking, wave properties and bubble-plume characteristics. Experiments were made in a large, freshwater, wind-wave channel with mechanical wind-steepened waves and a wind speed of 13 m s- 1. Bubble Plumes exhibited a wide range of bubble distributions, physical extent and dynamics. A classification scheme was developed based on plume extent and "optical density" which is the ability of a plume to optically obscure the image of the background until maximum penetration of the plume. Plumes were classified as either dense (obscure) or diffuse (no-obscure). For each class, the plume bubble population size distribution, Φ(r,t), where r is the bubble radius and t the time, was determined. Dense Plumes have a large radius peak in Φ and thus are enhanced in large bubbles. Diffuse Plumes are well-described by a weakly size decreasing Φ(r,t) for r 1000 μm. The bubble-plume formation rate, P, for each class, wave-breaking rate and wave characteristics were measured with respect to fetch. Wave-breaking rate and intensity are strongly fetch-dependent. In general, the trends in P and wave breaking are similar, reaching a maximum at the fetch of maximum wave breaking. The ratio of P for dense to diffuse Plumes is even more sensitive to the occurrence of the most intense wave breaking, where dense plume formation is the greatest. Using P and the bubble size population distributions for each plume class, the global bubble-plume, injection size distribution, Ψi(r), was calculated. The volume injection rate for the study area was 640 cm3 s- 1 divided approximately equally between bubbles smaller and larger than r ∼ 1700 μm. © 2006 Elsevier B.V. All rights reserved.
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Characteristics of Bubble Plumes, Bubble-Plume Bubbles, and Waves from Wind-Steepened Wave-Breaking
Journal of Marine Systems, 2007Co-Authors: Ira Leifer, Guillemette Caulliez, Gerrit De LeeuwAbstract:Observations of breaking waves, associated bubble Plumes and bubble-plume size distributions were used to explore the coupled evolution of wave-breaking, wave properties and bubble-plume characteristics. Experiments were made in a large, freshwater, wind-wave channel with mechanical wind-steepened waves and a wind speed of 13 m s-1. Bubble Plumes exhibited a wide range of bubble distributions, physical extent and dynamics. A classification scheme was developed based on plume extent and “optical density” which is the ability of a plume to optically obscure the image of the background until maximum penetration of the plume. Plumes were classified as either dense (obscure) or diffuse (no-obscure). For each class, the plume bubble population size distribution, Φ(r,t), where r is the bubble radius and t the time, was determined. Dense Plumes have a large radius peak in Φ and thus are enhanced in large bubbles. Diffuse Plumes are well-described by a weakly size decreasing Φ(r,t) for rb1000 μm and a more strongly size decreasing Φ(r,t) for rN1000 μm. The bubble-plume formation rate, P, for each class, wave-breaking rate and wave characteristics were measured with respect to fetch. Wave-breaking rate and intensity are strongly fetch-dependent. In general, the trends in P and wave breaking are similar, reaching a maximum at the fetch of maximum wave breaking. The ratio of P for dense to diffuse Plumes is even more sensitive to the occurrence of the most intense wave breaking, where dense plume formation is the greatest. Using P and the bubble size population distributions for each plume class, the global bubble-plume, injection size distribution, i(r), was calculated. The volume injection rate for the study area was 640 cm3 s-1 divided approximately equally between bubbles smaller and larger than r∼1700 μm.
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Characteristics of bubble Plumes, bubble-plume bubbles and waves from wind-steepened wave breaking
Journal of Marine Systems, 2007Co-Authors: Ira Leifer, Guillemette Caulliez, Gerrit De LeeuwAbstract:International audienceObservations of breaking waves, associated bubble Plumes and bubble-plume size distributions were used to explore the coupled evolution of wave-breaking, wave properties and bubble-plume characteristics. Experiments were made in a large, freshwater, wind-wave channel with mechanical wind-steepened waves and a wind speed of 13 m s-1. Bubble Plumes exhibited a wide range of bubble distributions, physical extent and dynamics. A classification scheme was developed based on plume extent and “optical density” which is the ability of a plume to optically obscure the image of the background until maximum penetration of the plume. Plumes were classified as either dense (obscure) or diffuse (no-obscure). For each class, the plume bubble population size distribution, Φ(r,t), where r is the bubble radius and t the time, was determined. Dense Plumes have a large radius peak in Φ and thus are enhanced in large bubbles. Diffuse Plumes are well-described by a weakly size decreasing Φ(r,t) for rb1000 μm and a more strongly size decreasing Φ(r,t) for rN1000 μm. The bubble-plume formation rate, P, for each class, wave-breaking rate and wave characteristics were measured with respect to fetch. Wave-breaking rate and intensity are strongly fetch-dependent. In general, the trends in P and wave breaking are similar, reaching a maximum at the fetch of maximum wave breaking. The ratio of P for dense to diffuse Plumes is even more sensitive to the occurrence of the most intense wave breaking, where dense plume formation is the greatest. Using P and the bubble size population distributions for each plume class, the global bubble-plume, injection size distribution, i(r), was calculated. The volume injection rate for the study area was 640 cm3 s-1 divided approximately equally between bubbles smaller and larger than r∼1700 μm
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Dense Bubble Plumes, Wave Breaking, and Air-Water Gas Exchange
2006Co-Authors: Ira Leifer, Guillemette Caulliez, Gerrit De LeeuwAbstract:Bubble-plume characteristics including the population size-distribution, F, plume formation rate, P, and wave-characteristics were measured for mechanical, wind-steepened wave breaking in a large, fresh-water wind-wave channel for 13 m s-1 wind speed. Bubble Plumes showed a wide diversity of F, physical extent, and dynamics, which were used to develop a classification scheme. The coupled evolution of wavebreaking, wave-properties, and bubble-plume characteristics were investigated. A significant differentiation amongst Plumes was some Plumes' ability to obscure optically (termed dense) the image background. Dense Plumes (as opposed to diffuse Plumes) were found to contain a large radius, r, peak in F - i.e., dense Plumes are enhanced in large bubbles. Population is the total number of bubbles in the plume. Diffuse Plumes are well-described by a shallowly decreasing F(r), for r < 1000 μm, and a more strongly decreasing F(r) for r > 1000 μm. For each class, P was determined and compared with the measured wave-breaking rate and wave characteristics with respect to fetch. The wave-breaking rate and intensity were strongly fetch dependent. In general, the trends in P and wave breaking are similar, reaching a maximum at the fetch of maximum wave breaking. The ratio of P for dense to diffuse Plumes is even more sensitive to the occurrence of the most intense wave breaking, where dense plume formation is the greatest. Using P and the bubble-size population distributions for each plume class, the global bubble-plume, injection size-distribution, Yi(r), was calculated and decreased as r-1.2, for r < 1700 μm and Yi ~ r-3.9 for larger r. The volume injection rate for the study area was 640 cm3 s-1 divided approximately equally between bubbles smaller and larger than r ~ 1700-μm. The significance of dense versus diffuse Plumes with respect to gas exchange of significant atmospheric gases was tested with a numerical bubble model and demonstrated that the large bubbles in dense Plumes plays a very significant roll in the overall bubble-mediated air-water gas exchange, including the dependency of gas exchange on solubility and Schmidt number.
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Bubbles Generated from Wind-Steepened Breaking Waves: Part 2. Bubble Plumes, Bubbles, and Wave Characteristics
Journal of Geophysical Research. Oceans, 2006Co-Authors: Ira Leifer, Guillemette Caulliez, Gerrit De LeeuwAbstract:Measurements of breaking-wave generated bubble Plumes were made in fresh (but not clean) water in a large wind-wave tunnel. To preserve diversity, a classification scheme was developed. based on plume dimensions and “optical density,” or the plume's ability to obscure the background. Optically dense Plumes were due to the presence of a peak at large radius in the plume bubble size-distribution. For each class, the plume formation rate, P, was measured at different fetches. The relationship between wave-breaking characteristics and the bubble-plume evolution is examined in detail for these experiments. The wave-breaking rate and intensity were strongly fetch dependent as the mechanically-steepened wind-waves rapidly evolved with fetch due to wind, dissipation, and non-linear wave-wave interactions. P followed the trend in wave breaking, reaching a maximum at the fetch of maximum wave breaking. The ratio of dense to diffuse Plumes was more sensitive to the wave-breaking intensity. Using P and the bubble population size-distributions for each class, the global bubble-plume, injection distribution, Yi(r), where r is radius, was calculated. Yi decreased as Yi~r-1.2, for r < 1700 µm and Yi~r-3.9 for larger r. Total volume injection was 640 cm3 s-1; divided approximately equally between bubbles smaller and larger than 1700-µm radius. Using plume volumes at maximum penetration for each class, a concentration distribution was calculated and showed plume concentrations greater than the background population by one to several orders of magnitude depending upon r.
K Wilhelm - One of the best experts on this subject based on the ideXlab platform.
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Morphology, dynamics and plasma parameters of Plumes and inter-plume regions in solar coronal holes
The Astronomy and Astrophysics Review, 2011Co-Authors: K Wilhelm, Lucia Abbo, Frédéric Auchère, Nicolas Barbey, Li Feng, A. H. Gabriel, Silvio Giordano, Shinsuke Imada, Antoine Llebaria, William H. MatthaeusAbstract:Coronal Plumes, which extend from solar coronal holes (CH) into the high corona and - possibly - into the solar wind (SW), can now continuously be studied with modern telescopes and spectrometers on spacecraft, in addition to investigations from the ground, in particular, during total eclipses. Despite the large amount of data available on these prominent features and related phenomena, many questions remained unanswered as to their generation and relative contributions to the high-speed streams emanating from CHs. An understanding of the processes of plume formation and evolution requires a better knowledge of the physical conditions at the base of CHs, in Plumes and in the surrounding inter-plume regions (IPR). More specifically, information is needed on the magnetic field configuration, the electron densities and temperatures, effective ion temperatures, non-thermal motions, plume cross-sections relative to the size of a CH, the plasma bulk speeds, as well as any plume signatures in the SW. In spring 2007, the authors proposed a study on "Structure and dynamics of coronal Plumes and inter-plume regions in solar coronal holes" to the International Space Science Institute (ISSI) in Bern to clarify some of these aspects by considering relevant observations and the extensive literature. This review summarizes the results and conclusions of the study. Stereoscopic observations allowed us to include three-dimensional reconstructions of Plumes. Multi-instrument investigations carried out during several campaigns led to progress in some areas, such as plasma densities, temperatures, plume structure and the relation to other solar phenomena, but not all questions could be answered concerning the details of plume generation process(es) and interaction with the SW.
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solar coronal hole plasma densities and temperatures
Astronomy and Astrophysics, 2006Co-Authors: K WilhelmAbstract:Polar Plumes extending from the Sun into the solar corona have long been seen during eclipses, and can now be studied without this restriction with telescopes and spectrometers on board of spacecraft. Despite the large amount of observational data available on this prominent phenomenon, it is not clear whether Plumes contribute substantially to the fast solar-wind streams emanating from coronal holes. An understanding of the processes leading to the formation of bright Plumes and the surrounding darker inter-plume regions in coronal holes requires a good knowledge of the physical conditions in Plumes and their environment. This investigation aims at measuring the electron densities and temperatures in these regions with the help of radiance ratios of ultraviolet emission lines obtained by SUMER on SOHO. It finds densities of about $7 \times 10^7$ cm -3 in bright Plumes and $1.3 \times 10^7$ cm -3 in inter-plume lanes at ≈ 45 Mm above the limb. At this height, the total plume cross-section relative to the size of the coronal hole was found to be less than 8%. The densities drop by a factor of roughly two over the next 80 Mm in height, in lanes a little less than seen in Plumes. In this height range, the electron temperatures in Plumes are ≈ $7.5 \times 10^5$ K and ≈ $1.13 \times 10^6$ K in inter-plume regions. The effective ion temperatures, deduced from the line widths, are higher and nearly independent of the altitude in Plumes, whereas they increase in inter-plume regions, starting from an even higher level. No systematic dependence of the line-of-sight bulk velocities on the brightness could be found in the coronal-hole plasma.
Matthew R Patrick - One of the best experts on this subject based on the ideXlab platform.
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dynamics of strombolian ash Plumes from thermal video motion morphology and air entrainment
Journal of Geophysical Research, 2007Co-Authors: Matthew R PatrickAbstract:[1] Imaging volcanic Plumes is essential to provide an observational basis for understanding and modeling plume dynamics. During June-July 2004, ∼150 Strombolian ash Plumes were imaged at Stromboli volcano, Italy, with a forward looking infrared radiometer (FLIR) thermal video camera (30 Hz). Of these, 25-80 Plumes were suited for different levels of quantitative analyses. In this study some simple analyses are applied to constrain basic parameters for the dynamics of Strombolian Plumes during their initial ascent (∼130 m). Plume rise rates covered both gas thrust (>15 m s -1 ) and buoyant regimes (<15 m s -1 ), which in turn controlled lateral spreading rates and air entrainment rates. The half angle of lateral spreading of the plume front averaged 7.3(±1.6)° for gas thrust regimes and 13.5(±1.6)° for buoyant regimes, equating to mean air entrainment coefficients of 0.06-0.12 for gas thrust regimes and 0.22(±0.03) for buoyant regimes. These factors were also linked to plume morphologies, which included jets, starting Plumes and thermals. A "rooted thermal" form was observed and presumed as an intermediary between starting Plumes and discrete thermals. Plume rise could be approximated by a power law dependence with time. Rooted thermals spread and entrained air at rates approaching those of a discrete thermal but rose at a rate similar to that of a starting plume. Phenomena including helical motion and sedimentation were visible in the FLIR imagery. These results demonstrate that emergent plume behavior is progressive and highly transient. Furthermore, this study offers empirical reinforcement that entrainment dynamics are intrinsically different in (1) gas thrust versus buoyantly driven regimes and (2) plume fronts versus steady Plumes.
