scholarly journals A Marine Aerosol Reference Tank system as a breaking wave analogue

2012 ◽  
Vol 5 (6) ◽  
pp. 8701-8728 ◽  
Author(s):  
M. D. Stokes ◽  
G. B. Deane ◽  
K. Prather ◽  
T. H. Bertram ◽  
M. J. Ruppel ◽  
...  
Keyword(s):  
Large Volume ◽  
Breaking Wave ◽  
Foam Formation ◽  
Marine Aerosol ◽  
Marine Aerosols ◽  
Bubble Plume ◽  
Tank System

Abstract. In order to better understand the processes governing the production of marine aerosols a repeatable, controlled method for their generation is required. The Marine Aerosol Reference Tank (MART) has been designed to closely approximate oceanic conditions by producing an evolving bubble plume and surface foam patch. The tank utilizes an intermittently plunging sheet of water and large volume tank reservoir to simulate turbulence, plume and foam formation, and is monitored volumetrically and acoustically to ensure the repeatability of conditions.

scholarly journals A Marine Aerosol Reference Tank system as a breaking wave analogue for the production of foam and sea-spray aerosols

2013 ◽  
Vol 6 (4) ◽  
pp. 1085-1094 ◽  
Author(s):  
M. D. Stokes ◽  
G. B. Deane ◽  
K. Prather ◽  
T. H. Bertram ◽  
M. J. Ruppel ◽  
...  
Keyword(s):  
Water Flow ◽  
Large Volume ◽  
Sea Spray ◽  
Breaking Wave ◽  
Foam Formation ◽  
Marine Aerosol ◽  
Marine Aerosols ◽  
Bubble Plume ◽  
Tank System

Abstract. In order to better understand the processes governing the production of marine aerosols a repeatable, controlled method for their generation is required. The Marine Aerosol Reference Tank (MART) has been designed to closely approximate oceanic conditions by producing an evolving bubble plume and surface foam patch. The tank utilizes an intermittently plunging sheet of water and large volume tank reservoir to simulate turbulence, plume and foam formation, and the water flow is monitored volumetrically and acoustically to ensure the repeatability of conditions.

scholarly journals A miniature Marine Aerosol Reference Tank (miniMART) as a compact breaking wave analogue

2016 ◽  
Vol 9 (9) ◽  
pp. 4257-4267 ◽  
Author(s):  
M. Dale Stokes ◽  
Grant Deane ◽  
Douglas B. Collins ◽  
Christopher Cappa ◽  
Timothy Bertram ◽  
...  
Keyword(s):  
Bulk Water ◽  
Breaking Wave ◽  
Foam Formation ◽  
Marine Aerosol ◽  
Marine Aerosols ◽  
Bubble Plume ◽  
Order Of Magnitude ◽  
Water Wheel ◽  
Spilling Breaker ◽  
New System

Abstract. In order to understand the processes governing the production of marine aerosols, repeatable, controlled methods for their generation are required. A new system, the miniature Marine Aerosol Reference Tank (miniMART), has been designed after the success of the original MART system, to approximate a small oceanic spilling breaker by producing an evolving bubble plume and surface foam patch. The smaller tank utilizes an intermittently plunging jet of water produced by a rotating water wheel, into an approximately 6 L reservoir to simulate bubble plume and foam formation and generate aerosols. This system produces bubble plumes characteristic of small whitecaps without the large external pump inherent in the original MART design. Without the pump it is possible to easily culture delicate planktonic and microbial communities in the bulk water during experiments while continuously producing aerosols for study. However, due to the reduced volume and smaller plunging jet, the absolute numbers of particles generated are approximately an order of magnitude less than in the original MART design.

scholarly journals A miniature Marine Aerosol Reference Tank (miniMART) as a compact breaking wave analogue

2016 ◽  
Author(s):  
M. Dale Stokes ◽  
Grant Deane ◽  
Douglas Collins ◽  
Christopher Cappa ◽  
Timothy Bertram ◽  
...  
Keyword(s):  
Bulk Water ◽  
Breaking Wave ◽  
Foam Formation ◽  
Marine Aerosol ◽  
Marine Aerosols ◽  
Bubble Plume ◽  
Order Of Magnitude ◽  
Water Wheel ◽  
Spilling Breaker ◽  
New System

Abstract. In order to understand the processes governing the production of marine aerosols, repeatable, controlled methods for their generation are required. A new system, the miniature Marine Aerosol Reference Tank (miniMART) has been designed after the success of the original MART system, to approximate a small oceanic spilling breaker by producing an evolving bubble plume and surface foam patch. The smaller tank utilizes an intermittently plunging jet of water produced by a rotating water wheel, into an approximately 6 L reservoir to simulate bubble plume and foam formation and generate aerosols. This system produces bubble plumes characteristic of small whitecaps without the large external pump inherent in the original MART design. Without the pump it is possible to easily culture delicate planktonic and microbial communities in the bulk water during experiments while continuously producing aerosols for study. However, due to the reduced volume and smaller plunging jet, the absolute numbers of particles generated are approximately an order of magnitude less than in the original MART design.

Applications of a Scattering Spectrometer System for Marine Aerosol Measurement

1977 ◽  
Vol 99 (4) ◽  
pp. 533-536
Author(s):  
C. N. Shen ◽  
E. W. Mihalek
Keyword(s):  
Laser Radiation ◽  
Real Time ◽  
Data Reduction ◽  
Coherent Scattering ◽  
Distribution Data ◽  
Marine Aerosol ◽  
Marine Aerosols ◽  
Aerosol Measurement ◽  
Spectrometer System ◽  
Resolution Data

A newly developed instrument has been successfully evaluated and applied to the measurement of marine aerosols. The instrument, known as the Scattering Spectrometer System (SSS), utilizes coherent scattering of laser radiation to size marine aerosols in flight and produce size distribution data in real time. Compared to current methods of using source cascade impactors, the SSS was found superior in terms of resolution, data reduction simplicity, and real-time capability. The application of the SSS at the Naval Air Propulsion Test Center (NAPTC) includes real-time facility diagnostics, control, and calibration. Novel information concerning aerosol separators has also been uncovered using the SSS.

A Coupled VOF-Eulerian Multiphase CFD Model to Simulate Breaking Wave Impacts on Offshore Structures

2016 ◽  
Author(s):  
Pietro D. Tomaselli ◽  
Erik Damgaard Christensen
Keyword(s):  
Wave Breaking ◽  
Bubble Column ◽  
Vertical Cylinder ◽  
Air Entrainment ◽  
Offshore Structures ◽  
Laboratory Scale ◽  
Breaking Wave ◽  
Cfd Model ◽  
Bubble Plume ◽  
Wave Induced

Breaking wave-induced loads on offshore structures can be extremely severe. The air entrainment mechanism during the breaking process plays a not well-known role in the exerted forces. This paper present a CFD solver, developed in the Open-FOAM environment, capable of simulating the wave breaking-induced air entrainment. Firstly the model was validated against a bubble column flow. Then it was employed to compute the inline force exerted by a spilling breaking wave on a vertical cylinder in a 3D domain at a laboratory scale. Results showed that the entrained bubbles affected the magnitude of the force partially. Further analyses on the interaction of the bubble plume with the flow around the cylinder are needed.

scholarly journals Spaceborne observations of the lidar ratio of marine aerosols

2015 ◽  
Vol 15 (6) ◽  
pp. 3241-3255 ◽  
Author(s):  
K. W. Dawson ◽  
N. Meskhidze ◽  
D. Josset ◽  
S. Gassó
Keyword(s):  
Optical Depth ◽  
Surface Wind ◽  
Spatiotemporal Variability ◽  
Retrieval Algorithm ◽  
Orthogonal Polarization ◽  
Aerosol Layer ◽  
Marine Aerosol ◽  
Marine Aerosols ◽  
Lidar Ratio ◽  
The Mean

Abstract. Retrievals of aerosol optical depth (AOD) from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) satellite sensor require the assumption of the extinction-to-backscatter ratio, also known as the lidar ratio. This paper evaluates a new method to calculate the lidar ratio of marine aerosols using two independent sources: the AOD from the Synergized Optical Depth of Aerosols (SODA) project and the integrated attenuated backscatter from CALIOP. With this method, the particulate lidar ratio can be derived for individual CALIOP retrievals in single aerosol layer, cloud-free columns over the ocean. Global analyses are carried out using CALIOP level 2, 5 km marine aerosol layer products and the collocated SODA nighttime data from December 2007 to November 2010. The global mean lidar ratio for marine aerosols was found to be 26 sr, roughly 30% higher than the current value prescribed by the CALIOP standard retrieval algorithm. Data analysis also showed considerable spatiotemporal variability in the calculated lidar ratio over the remote oceans. The calculated marine aerosol lidar ratio is found to vary with the mean ocean surface wind speed (U10). An increase in U10 reduces the mean lidar ratio for marine regions from 32 ± 17 sr (for 0 < U10 < 4 m s−1) to 22 ± 7 sr (for U10 > 15 m s−1). Such changes in the lidar ratio are expected to have a corresponding effect on the marine AOD from CALIOP. The outcomes of this study are relevant for future improvements of the SODA and CALIOP operational product and could lead to more accurate retrievals of marine AOD.

scholarly journals Tara Pacific Expedition’s Atmospheric Measurements of Marine Aerosols across the Atlantic and Pacific Oceans: Overview and Preliminary Results

2020 ◽  
Vol 101 (5) ◽  
pp. E536-E554 ◽  
Author(s):  
J. M. Flores ◽  
G. Bourdin ◽  
O. Altaratz ◽  
M. Trainic ◽  
N. Lang-Yona ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Chemical Properties ◽  
Number Concentration ◽  
Marine Atmosphere ◽  
Marine Aerosol ◽  
Marine Aerosols ◽  
Atmospheric Measurements ◽  
Preliminary Results ◽  
Production Mechanisms

Abstract 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 of measurements. It will characterize marine aerosols properties in detail and will open a new window to study the marine aerosol link to the water properties and environmental conditions.

scholarly journals Deriving the effect of wind speed on clean marine aerosol optical properties using the A-Train satellites

2011 ◽  
Vol 11 (22) ◽  
pp. 11401-11413 ◽  
Author(s):  
V. P. Kiliyanpilakkil ◽  
N. Meskhidze
Keyword(s):  
Optical Properties ◽  
Wind Speed ◽  
Optical Depth ◽  
Surface Wind ◽  
Surface Wind Speed ◽  
Marine Aerosol ◽  
Marine Aerosols ◽  
Aerosol Optical Properties ◽  
The Mean ◽  
532 Nm

Abstract. The relationship between "clean marine" aerosol optical properties and ocean surface wind speed is explored using remotely sensed data from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on board the CALIPSO satellite and the Advanced Microwave Scanning Radiometer (AMSR-E) on board the AQUA satellite. Detailed data analyses are carried out over 15 regions selected to be representative of different areas of the global ocean for the time period from June 2006 to April 2011. Based on remotely sensed optical properties the CALIPSO algorithm is capable of discriminating "clean marine" aerosols from other types often present over the ocean (such as urban/industrial pollution, desert dust and biomass burning). The global mean optical depth of "clean marine" aerosol at 532 nm (AOD532) is found to be 0.052 ± 0.038 (mean plus or minus standard deviation). The mean layer integrated particulate depolarization ratio of marine aerosols is 0.02 ± 0.016. Integrated attenuated backscatter and color ratio of marine aerosols at 532 nm were found to be 0.003 ± 0.002 sr−1 and 0.530 ± 0.149, respectively. A logistic regression between AOD532 and 10-m surface wind speed (U10) revealed three distinct regimes. For U10 ≤ 4 m s−1 the mean CALIPSO-derived AOD532 is found to be 0.02 ± 0.003 with little dependency on the surface wind speed. For 4 < U10 ≤ 12 m s−1, representing the dominant fraction of all available data, marine aerosol optical depth is linearly correlated with the surface wind speed values, with a slope of 0.006 s m−1. In this intermediate wind speed region, the AOD532 vs. U10 regression slope derived here is comparable to previously reported values. At very high wind speed values (U10 > 18 m s−1), the AOD532-wind speed relationship showed a tendency toward leveling off, asymptotically approaching value of 0.15. The conclusions of this study regarding the aerosol extinction vs. wind speed relationship may have been influenced by the constant lidar ratio used for CALIPSO-derived AOD532. Nevertheless, active satellite sensor used in this study that allows separation of maritime wind induced component of AOD from the total AOD over the ocean could lead to improvements in optical properties of sea spray aerosols and their production mechanisms.

scholarly journals Air entrainment and bubble statistics in breaking waves

2016 ◽  
Vol 801 ◽  
pp. 91-129 ◽  
Author(s):  
Luc Deike ◽  
W. Kendall Melville ◽  
Stéphane Popinet
Keyword(s):  
Size Distribution ◽  
Bubble Size ◽  
Dissipation Rate ◽  
Unit Length ◽  
Bubble Radius ◽  
Air Entrainment ◽  
Breaking Waves ◽  
Bubble Size Distribution ◽  
Breaking Wave ◽  
Bubble Plume

We investigate air entrainment and bubble statistics in three-dimensional breaking waves through novel direct numerical simulations of the two-phase air–water flow, resolving the length scales relevant for the bubble formation problem, the capillary length and the Hinze scale. The dissipation due to breaking is found to be in good agreement with previous experimental observations and inertial scaling arguments. The air entrainment properties and bubble size statistics are investigated for various initial characteristic wave slopes. For radii larger than the Hinze scale, the bubble size distribution, can be described by $N(r,t)=B(V_{0}/2{\rm\pi})({\it\varepsilon}(t-{\rm\Delta}{\it\tau})/Wg)r^{-10/3}r_{m}^{-2/3}$ during the active breaking stages, where ${\it\varepsilon}(t-{\rm\Delta}{\it\tau})$ is the time-dependent turbulent dissipation rate, with ${\rm\Delta}{\it\tau}$ the collapse time of the initial air pocket entrained by the breaking wave, $W$ a weighted vertical velocity of the bubble plume, $r_{m}$ the maximum bubble radius, $g$ gravity, $V_{0}$ the initial volume of air entrained, $r$ the bubble radius and $B$ a dimensionless constant. The active breaking time-averaged bubble size distribution is described by $\bar{N}(r)=B(1/2{\rm\pi})({\it\epsilon}_{l}L_{c}/Wg{\it\rho})r^{-10/3}r_{m}^{-2/3}$, where ${\it\epsilon}_{l}$ is the wave dissipation rate per unit length of breaking crest, ${\it\rho}$ the water density and $L_{c}$ the length of breaking crest. Finally, the averaged total volume of entrained air, $\bar{V}$, per breaking event can be simply related to ${\it\epsilon}_{l}$ by $\bar{V}=B({\it\epsilon}_{l}L_{c}/Wg{\it\rho})$, which leads to a relationship for a characteristic slope, $S$, of $\bar{V}\propto S^{5/2}$. We propose a phenomenological turbulent bubble break-up model based on earlier models and the balance between mechanical dissipation and work done against buoyancy forces. The model is consistent with the numerical results and existing experimental results.

scholarly journals Hygroscopic and volatile properties of marine aerosol observed at Cape Grim during the P2P campaign

2007 ◽  
Vol 4 (3) ◽  
pp. 162 ◽  
Author(s):  
Catherine A. Fletcher ◽  
Graham R. Johnson ◽  
Zoran D. Ristovski ◽  
Mike Harvey
Keyword(s):  
Organic Matter ◽  
Ammonium Sulfate ◽  
Organic Content ◽  
Major Influence ◽  
Radiation Balance ◽  
Marine Aerosol ◽  
Marine Aerosols ◽  
Hygroscopic Growth ◽  
Accumulation Mode ◽  
Cape Grim

Environmental context. The marine environment covers 71% of the Earth’s surface, and accounts for most of the planet’s cloud cover. Water droplets in these clouds all form on pre-existing marine aerosol particles. The number, size and composition of these particles determine the cloud droplet size and consequently, the cloud’s light scattering and precipitation behaviour. Marine aerosols, therefore, have a major influence on the planet’s radiation balance and climate. The origin of marine aerosols is still not completely resolved. The newly developed VH-TDMA technique has been applied to marine aerosols that come from the Southern Ocean. The technique enabled new insights into the composition and structure of these aerosols. It has been found that organic matter constitutes 20–40% of these particles, which suppresses their hygroscopic growth. Abstract. Simultaneous measurement of particle hygroscopic and volatile properties was performed using a VH-TDMA on both Aitken and accumulation mode particles. In addition, deliquescence measurements at different thermodenuder temperatures were also performed. The measurements were part of the P2P campaign which took place in February 2006 at the Cape Grim monitoring station in Tasmania, Australia. During baseline conditions, there was often a volatilisation step that occurred below 125°C in the volatility scans, where up to 25% of the volume is lost. Analysis of the changes in growth as this took place indicates that different substances are responsible for this volatilisation on different days – ammonium nitrate, sulfuric acid, or a volatile non-hygroscopic organic. The major volatilisation in all cases occurred in the temperature range ~140–200°C, which is taken to indicate the presence of ammonium sulfate or ammonium bisulfate. A degree of growth suppression is generally evident before this volatilisation, which indicates that a non-hygroscopic material with a similar volatility to ammonium sulfate/bisulfate may be present, which cannot be distinguished in the volatility scans. Organic matter was typically present at around ~20–40% for these particles. When Aitken and accumulation mode particles were measured on the same day, it was found that the organic content of the smaller particles tended to be higher than the larger particles by roughly 20 percentage points.

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