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Smith, M. H., et N. M. Harrison. « The sea spray generation function ». Journal of Aerosol Science 29 (septembre 1998) : S189—S190. http://dx.doi.org/10.1016/s0021-8502(98)00280-8.
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Andreas, Edgar L. « Sea Spray Generation at a Rocky Shoreline ». Journal of Applied Meteorology and Climatology 55, no 9 (septembre 2016) : 2037–52. http://dx.doi.org/10.1175/jamc-d-15-0211.1.
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AbstractWith sea ice in the Arctic continuing to shrink, the Arctic Ocean and the surrounding marginal seas will become more like the ocean at lower latitudes. In particular, with more open water, air–sea exchange will be more intense and storms will be stronger and more frequent. The longer fetches over open water and the more energetic storms will combine to produce higher waves and more sea spray. Offshore structures—such as oil drilling, exploration, and production platforms—will face increased hazards from freezing sea spray. On the basis of sea spray observations made with a cloud-imaging probe at Mount Desert Rock (an island off the coast of Maine), the spray that artificial islands built in the Arctic might experience is quantified. Mount Desert Rock is small, low, and unvegetated and has an abrupt, rocky shoreline like these artificial islands might have. Many of the observations were at air temperatures below freezing. This paper reports the near-surface spray concentration and the rate of spray production at this rocky shoreline for spray droplets with radii from 6.25 to 143.75 μm and for wind speeds from 5 to 17 m s−1. Spray concentration increases as the cube of the wind speed, but the shape of the concentration spectrum with respect to radius does not change with wind speed. Both near-surface spray concentration and the spray-production rate are three orders of magnitude higher at this rocky shoreline than over the open ocean because of the high energy and resulting continuous white water in the surf zone.
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Ortiz-Suslow, David G., Brian K. Haus, Sanchit Mehta et Nathan J. M. Laxague. « Sea Spray Generation in Very High Winds ». Journal of the Atmospheric Sciences 73, no 10 (21 septembre 2016) : 3975–95. http://dx.doi.org/10.1175/jas-d-15-0249.1.
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Abstract Quantifying the amount and rate of sea spray production at the ocean surface is critical to understanding the effect spray has on atmospheric boundary layer processes (e.g., tropical cyclones). Currently, only limited observational data exist that can be used to validate available droplet production models. To help fill this gap, a laboratory experiment was conducted that directly observed the vertical distribution of spume droplets above actively breaking waves. The experiments were carried out in hurricane-force conditions (10-m equivalent wind speed of 36–54 m s−1), and the observed particles ranged in radius r from 80 to nearly 1400 μm. High-resolution profiles (3 mm) were reconstructed from optical imagery taken within the boundary layer, ranging from 2 to 6 times the local significant wave height. Number concentrations were observed to have a radius dependence proportional to r−3 leading to spume production estimates that diverge from typical source models, which tend to exhibit a radius falloff closer to r−8. This was particularly significant for droplets with radii circa 1 mm whose modeled production rates were several orders of magnitude less than the rates expected from the observed concentrations. The vertical dependence of the number concentrations was observed to follow a logarithmic profile, which does not confirm the power-law relationship expected by a conventional spume generation parameterization. These observations bear significant implications for efforts to characterize the role these large droplets play in boundary layer processes under high-wind conditions.
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Mueller, James A., et Fabrice Veron. « A Sea State–Dependent Spume Generation Function ». Journal of Physical Oceanography 39, no 9 (1 septembre 2009) : 2363–72. http://dx.doi.org/10.1175/2009jpo4113.1.
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Abstract The uncertainty of the sea spray generation function continues to obscure spray-mediated momentum and scalar fluxes, especially for intense wind conditions. Most previous studies assume a constant form (spectral shape) for the droplet distribution, even though a shift to smaller drops with increased wind forcing is expected. In this paper, a new generation function for spume drops is derived, but unlike previous studies, both its form and magnitude change with wind forcing. Fairly good agreement is found between this spume generation function and the limited data available. A potential explanation for the vast size differences among previous spume generation studies is also provided by distinguishing the drops formed at the surface from the drops transported vertically where measurements are routinely made.
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Mueller, James A., et Fabrice Veron. « Impact of Sea Spray on Air–Sea Fluxes. Part II : Feedback Effects ». Journal of Physical Oceanography 44, no 11 (1 novembre 2014) : 2835–53. http://dx.doi.org/10.1175/jpo-d-13-0246.1.
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Abstract This paper presents estimations for the transfer of momentum, heat, and water mass between the air and the sea. The results from Lagrangian stochastic simulations of sea spray drops (see Part I), along with two sea spray generation functions, are used to calculate the spray-mediated flux components of the air–sea fluxes. When the spray-mediated fluxes constitute a significant fraction of the total fluxes under certain conditions, their feedback effect on the atmosphere cannot be neglected. The authors derive a simplified feedback model to investigate such cases, finding that the spray-mediated fluxes may be especially sensitive to the size distribution of the drops. The total effective air–sea fluxes lead to drag and enthalpy coefficients that increase modestly with wind speed. The rate of increase for the drag coefficient is greatest at moderate wind speeds, while the rate of increase for the enthalpy coefficient is greatest at higher wind speeds where the spray is ubiquitous.
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Garg, Nikhil, Eddie Yin Kwee Ng et Srikanth Narasimalu. « The effects of sea spray and atmosphere–wave coupling on air–sea exchange during a tropical cyclone ». Atmospheric Chemistry and Physics 18, no 8 (27 avril 2018) : 6001–21. http://dx.doi.org/10.5194/acp-18-6001-2018.
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Abstract. The study investigates the role of the air–sea interface using numerical simulations of Hurricane Arthur (2014) in the Atlantic. More specifically, the present study aims to discern the role ocean surface waves and sea spray play in modulating the intensity and structure of a tropical cyclone (TC). To investigate the effects of ocean surface waves and sea spray, numerical simulations were carried out using a coupled atmosphere–wave model, whereby a sea spray microphysical model was incorporated within the coupled model. Furthermore, this study also explores how sea spray generation can be modelled using wave energy dissipation due to whitecaps; whitecaps are considered as the primary mode of spray droplets generation at hurricane intensity wind speeds. Three different numerical simulations including the sea- state-dependent momentum flux, the sea-spray-mediated heat flux, and a combination of the former two processes with the sea-spray-mediated momentum flux were conducted. The foregoing numerical simulations were evaluated against the National Data Buoy Center (NDBC) buoy and satellite altimeter measurements as well as a control simulation using an uncoupled atmosphere model. The results indicate that the model simulations were able to capture the storm track and intensity: the surface wave coupling results in a stronger TC. Moreover, it is also noted that when only spray-mediated heat fluxes are applied in conjunction with the sea-state-dependent momentum flux, they result in a slightly weaker TC, albeit stronger compared to the control simulation. However, when a spray-mediated momentum flux is applied together with spray heat fluxes, it results in a comparably stronger TC. The results presented here allude to the role surface friction plays in the intensification of a TC.
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Wan, Zhanhong, Luping Li, Zhigen Wu, Jiawang Chen et Xiuyang Lü. « The impact of ocean waves on spray stress and surface drag coefficient ». International Journal of Numerical Methods for Heat & ; Fluid Flow 29, no 2 (4 février 2019) : 523–35. http://dx.doi.org/10.1108/hff-05-2018-0237.
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Purpose The behaviors of sea surface drag coefficient should be well understood for an accurate hurricane prediction. The speed of wind has been applied to characterize the spray production; however, this could result in inaccurate spray productions compared to the experimental or field data if the influence of wave state is not considered. This paper aims to integrate a new sea spray generation function, described by windsea Reynolds number, into the spray momentum flux formula to calculate the spray momentum. Design/methodology/approach On the basis of this spray momentum, this study proposes the new formulas of spray stress and drag coefficient when the wind speed is high. Findings Results of the revised formulas show that wave status had significant effects on the spray stress and sea surface drag coefficient. Also, wave age was found to be an important parameter that affects the drag coefficient. The drag coefficient decreased with the increasing wave age. Comparison between this study’s theoretical and observation values of drag coefficient shows that the study results are close to the measured values. Research limitations/implications The research findings can enhance the understanding of the behaviors of sea surface drag for an accurate hurricane prediction. Originality/value A new sea spray generation function, described by windsea Reynolds number, is integrated into the spray momentum flux formula to calculate the spray momentum. On the basis of this spray momentum, this study proposes the new formulas of spray stress and drag coefficient when the wind speed is high.
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Bao, J. W., C. W. Fairall, S. A. Michelson et L. Bianco. « Parameterizations of Sea-Spray Impact on the Air–Sea Momentum and Heat Fluxes ». Monthly Weather Review 139, no 12 (1 décembre 2011) : 3781–97. http://dx.doi.org/10.1175/mwr-d-11-00007.1.
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Abstract This paper focuses on parameterizing the effect of sea spray at hurricane-strength winds on the momentum and heat fluxes in weather prediction models using the Monin–Obukhov similarity theory (a common framework for the parameterizations of air–sea fluxes). In this scheme, the mass-density effect of sea spray is considered as an additional modification to the stratification of the near-surface profiles of wind, temperature, and moisture in the marine surface boundary layer (MSBL). The overall impact of sea-spray droplets on the mean profiles of wind, temperature, and moisture depends on the wind speed at the level of sea-spray generation. As the wind speed increases, the mean droplet size and the mass flux of sea-spray increase, rendering an increase of stability in the MSBL and the leveling-off of the surface drag. Sea spray also tends to increase the total air–sea sensible and latent heat fluxes at high winds. Results from sensitivity testing of the scheme in a numerical weather prediction model for an idealized case of hurricane intensification are presented along with a dynamical interpretation of the impact of the parameterized sea-spray physics on the structure of the hurricane boundary layer.
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Piazzola, J., P. Forget et S. Despiau. « A sea spray generation function for fetch-limited conditions ». Annales Geophysicae 20, no 1 (31 janvier 2002) : 121–31. http://dx.doi.org/10.5194/angeo-20-121-2002.
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Abstract. This paper presents a sea spray generation function for aerosols produced by bubbles bursting that accounts for the effects of fetch. This is achieved by introducing a fetch-dependent model for the whitecap fraction, which is valid for fetch-limited conditions, i.e. steady-state conditions of the wave field in the whitecap droplet flux derived by Monahan et al. (1986). The aerosol generation fluxes calculated by this method show an enhancement of the aerosol production with increasing fetch. However, the predicted generation fluxes are lower than those calculated by using the classical model for the whitecap fraction proposed by Monahan and O’Muircheartaigh (1980). The results are then compared to aerosol size distributions measured in a Mediterranean coastal site at various fetch lengths. The data confirm the role of fetch, through its influence on marine aerosol generation and subsequent particle dispersion. The aerosol size distributions are divided into "fine" and "coarse" fractions. Submicrometer particles decrease in concentration at larger fetch, while the concentrations of super micron aerosols increase with increasing fetch.Key words. Atmospheric composition and structure (aerosols and particles) Meteorology and atmospheric dynamics (waves and ties) Oceanography: physical (air-sea interactions)
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Zhang, Ting. « The Impact of Surface Waves and Spray Injection Velocities on Air–Sea Momentum and Heat Fluxes ». Atmosphere 14, no 10 (28 septembre 2023) : 1500. http://dx.doi.org/10.3390/atmos14101500.
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Surface waves and sea spray play a significant role in air–sea fluxes in high winds. The present study used a marine atmosphere surface layer (MASL), which couples the traditional Monin–Obukhov similarity theory, sea spray generation function, the balance of turbulent kinetic budget, and momentum/enthalpy conservation equations. Based on this model, the effects of wave states and spray injection velocities on air–sea momentum/enthalpy fluxes and near-surface wind/temperature profiles were theoretically investigated. Based on the assumption that the velocity of injected spray is the same as that of the ambient airflow, it was found that spray could increase the near-surface air turbulence intensity and inhibit air–sea fluxes at 10 m above the sea surface. Correspondingly, near-surface wind speeds and temperature increase in high winds. This phenomenon becomes prominent in cases of large wave ages or surface waves supporting a minority of air–sea fluxes. Based on the assumption that the velocity of the edges of breaking water bags is used to estimate that of spray injection, the opposite results were found: spray could weaken the near-surface air turbulence and increase total air–sea fluxes at 10 m above the sea surface. In this case, the near-surface wind speeds and temperature decreased. This reduction becomes remarkable when surface waves are full-developed or the majority of air–sea momentum fluxes are supported by waves.
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Shi, Jian, Zhihao Feng, Yuan Sun, Xueyan Zhang, Wenjing Zhang et Yi Yu. « Relationship between Sea Surface Drag Coefficient and Wave State ». Journal of Marine Science and Engineering 9, no 11 (10 novembre 2021) : 1248. http://dx.doi.org/10.3390/jmse9111248.
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The sea surface drag coefficient plays an important role in momentum transmission between the atmosphere and the ocean, which is affected by ocean waves. The total air–sea momentum flux consists of effective momentum flux and sea spray momentum flux. Sea spray momentum flux involves sea surface drag, which is largely affected by the ocean wave state. Under strong winds, the sea surface drag coefficient (CD) does not increase linearly with the increasing wind speed, namely, the increase of CD is inhibited by strong winds. In this study, a sea surface drag coefficient is constructed that can be applied to the calculation of the air–sea momentum flux under high wind speed. The sea surface drag coefficient also considers the influence of wave state and sea spray droplets generated by wave breaking. Specially, the wave-dependent sea spray generation function is employed to calculate sea spray momentum flux. This facilitates the analysis not only on the sensitivity of the sea spray momentum flux to wave age, but also on the effect of wave state on the effective CD (CD, eff) under strong winds. Our results indicate that wave age plays an important role in determining CD. When the wave age is >0.4, CD decreases with the wave age. However, when the wave age is ≤0.4, CD increases with the wave age at low and moderate wind speeds but tends to decrease with the wave age at high wind speeds.
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Liu, Shang, Cheng-Cheng Liu, Karl D. Froyd, Gregory P. Schill, Daniel M. Murphy, T. Paul Bui, Jonathan M. Dean-Day et al. « Sea spray aerosol concentration modulated by sea surface temperature ». Proceedings of the National Academy of Sciences 118, no 9 (22 février 2021) : e2020583118. http://dx.doi.org/10.1073/pnas.2020583118.
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Natural aerosols in pristine regions form the baseline used to evaluate the impact of anthropogenic aerosols on climate. Sea spray aerosol (SSA) is a major component of natural aerosols. Despite its importance, the abundance of SSA is poorly constrained. It is generally accepted that wind-driven wave breaking is the principle governing SSA production. This mechanism alone, however, is insufficient to explain the variability of SSA concentration at given wind speed. The role of other parameters, such as sea surface temperature (SST), remains controversial. Here, we show that higher SST promotes SSA mass generation at a wide range of wind speed levels over the remote Pacific and Atlantic Oceans, in addition to demonstrating the wind-driven SSA production mechanism. The results are from a global scale dataset of airborne SSA measurements at 150 to 200 m above the ocean surface during the NASA Atmospheric Tomography Mission. Statistical analysis suggests that accounting for SST greatly enhances the predictability of the observed SSA concentration compared to using wind speed alone. Our results support implementing SST into SSA source functions in global models to better understand the atmospheric burdens of SSA.
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Shi, Jian, Wenjing Zhang, Xueyan Zhang, Jingdong Liu et Zhenyu Liu. « Parameterization of the sea spray generation function with whitecap coverage ». Acta Oceanologica Sinica 39, no 8 (août 2020) : 24–33. http://dx.doi.org/10.1007/s13131-020-1618-9.
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Chen, Jiajing, Xu Bai, Jialu Wang, Guanyu Chen et Tao Zhang. « Research on Sea Spray Distribution of Marine Vessels Based on SPH-FEM Coupling Numerical Simulation Method ». Water 14, no 23 (24 novembre 2022) : 3834. http://dx.doi.org/10.3390/w14233834.
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Due to the effect of the maritime environment and low temperature factor, ice phenomena are easily produced while a ship is sailing in a polar location. Types of ice accumulation include sea spray icing, which accounts for 90% of all ice accumulation, and, therefore, sea spray generation is a crucial step in ice accumulation prediction research. In order to investigate the phenomenon of ice formation on ships, this paper uses the SPH-FEM (Smooth Particle Hydrodynamics-Finite Element) coupling approach in this paper, and tracks the data pertaining to the wave current particles by simulating the impact of a single wave on the ship hull under the wave height standard of various sea conditions. Following the numerical simulation, it was discovered that when the sea state reaches five levels, the waves will produce marine sea spray on the simulated hull and distribute them in an arc on both sides of the hull; the phenomenon is influenced by the sea state level, meaning that the arc becomes more obvious as the sea state level rises. Furthermore, the number of sea spray particles formed in different sea state levels accounts for about 9–13% of the range of individual waves, and the rest of the sea spray particles will flow back to the surface quickly after passing through the hull.
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Liu, Bin, ChangLong Guan, LiAn Xie et DongLiang Zhao. « Derivation of a wave-state-dependent sea spray generation function and its application in estimating sea spray heat flux ». Science China Earth Sciences 58, no 10 (29 août 2015) : 1862–71. http://dx.doi.org/10.1007/s11430-015-5169-4.
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Yamashiro, Masaru, Akinori Yoshida et Yasuhiro Nishii. « PRACTICAL MEASURES AGAINST SEA SALT PARTICLES FROM AN EXISTING VERTICAL WALL ». Coastal Engineering Proceedings 1, no 32 (31 janvier 2011) : 31. http://dx.doi.org/10.9753/icce.v32.structures.31.
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At Waku fishing port, facing to Japan Sea, in Yamaguchi prefecture, Japan, a vertical type breakwater was constructed in front of the mouth of the port to protect the inside against incoming waves about 10 years ago. Residents in the area have been troubled with heavy seawater spray and much smaller sea salt particles caused at the breakwater by sever waves and strong winds ever since. To reduce the generation of and the damage from the seawater spray and the sea salt particles, three different types of measures were proposed: (a) covering the breakwater with wave dissipating blocks, (b) construction of a low crested offshore breakwater some distance ahead of the breakwater, and (c) construction of an artificial reef some distance ahead of the breakwater. Laboratory experiments using a wave flume with a wind tunnel were conducted to compare the effects of suppressing the water spray generation. The results of the comparative experiments showed that the covering with the wave dissipating blocks (Plan (a)) is the most effective means.
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Lenain, Luc, et W. Kendall Melville. « Evidence of Sea-State Dependence of Aerosol Concentration in the Marine Atmospheric Boundary Layer ». Journal of Physical Oceanography 47, no 1 (janvier 2017) : 69–84. http://dx.doi.org/10.1175/jpo-d-16-0058.1.
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AbstractSea spray aerosols represent a large fraction of the aerosols present in the maritime environment. Despite evidence of the importance of surface wave– and wave breaking–related processes in coupling the ocean with the atmosphere, sea spray source generation functions are traditionally parameterized by the 10-m wind speed U10 alone. It is clear that unless the wind and wave field are fully developed, the source function will be a function of both wind and wave parameters. This study reports primarily on the aerosol component of an air–sea interaction experiment, the phased-resolved High-Resolution Air–Sea Interaction Experiment (HIRES), conducted off the coast of northern California in June 2010. Detailed measurements of aerosol number concentration in the marine atmospheric boundary layer (MABL) at altitudes ranging from as low as 30 m up to 800 m above mean sea level (MSL) over a broad range of environmental conditions (significant wave height Hs of 2 to 4.5 m and U10 from 10 to 18 m s−1) collected from an instrumented research aircraft are presented. Aerosol number densities and volume are computed over a range of particle diameters from 0.1 to 200 μm, while the sea surface conditions, including Hs, moments of the breaker length distribution Λ(c), and wave breaking dissipation, were measured by a suite of electro-optical sensors that included the NASA Airborne Topographic Mapper (ATM). The sea-state dependence of the aerosol concentration in the MABL is evident, stressing the need to incorporate wave parameters in the spray source generation functions that are traditionally parameterized by surface winds alone.
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Deike, Luc. « Mass Transfer at the Ocean–Atmosphere Interface : The Role of Wave Breaking, Droplets, and Bubbles ». Annual Review of Fluid Mechanics 54, no 1 (5 janvier 2022) : 191–224. http://dx.doi.org/10.1146/annurev-fluid-030121-014132.
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Breaking waves modulate the transfer of energy, momentum, and mass between the ocean and atmosphere, controlling processes critical to the climate system, from gas exchange of carbon dioxide and oxygen to the generation of sea spray aerosols that can be transported in the atmosphere and serve as cloud condensation nuclei. The smallest components, i.e., drops and bubbles generated by breaking waves, play an outsize role. This fascinating problem is characterized by a wide range of length scales, from wind forcing the wave field at scales of [Formula: see text](1 km–0.1 m) to the dynamics of wave breaking at [Formula: see text](10–0.1 m); air bubble entrainment, dynamics, and dissolution in the water column at [Formula: see text](1 m–10 μm); and bubbles bursting at [Formula: see text](10 mm–1 μm), generating sea spray droplets at [Formula: see text](0.5 mm–0.5 μm) that are ejected into atmospheric turbulent boundary layers. I discuss recent progress to bridge these length scales, identifying the controlling processes and proposing a path toward mechanistic parameterizations of air–sea mass exchange that naturally accounts for sea state effects.
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Gall, Jeffrey S., William M. Frank et Young Kwon. « Effects of Sea Spray on Tropical Cyclones Simulated under Idealized Conditions ». Monthly Weather Review 136, no 5 (1 mai 2008) : 1686–705. http://dx.doi.org/10.1175/2007mwr2183.1.
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Abstract Under high-wind conditions, breaking waves and whitecaps eject large numbers of sea spray droplets into the atmosphere. The spray droplets originate with the same temperature and salinity as the ocean surface and thus increase the effective surface area of the ocean in contact with the atmosphere. As a result, the spray alters the total sensible and latent heat fluxes in the near-surface layer. The spray drops in the near-surface layer also result in horizontal and vertical spray-drag effects. The mass of the spray introduces an additional drag in the vertical momentum equation and tends to stabilize the lower boundary layer (BL). An initially axisymmetric control hurricane was created from the output of a real-data simulation of Hurricane Floyd (1999) using the nonhydrostatic fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5, version 3.4). The subsequent simulations, however, are not axisymmetric because the mass, wind, and spray fields are allowed to develop asymmetries. While such a design does not result in an axisymmetric simulation, the mass, wind, and spray fields develop more realistic structures than in an axisymmetric simulation. Simulations of the hurricane were conducted using a version of the Fairall et al. (1994) sea spray parameterization, which includes horizontal and vertical spray-drag effects. The simulations were run using varying spray-source function intensities and with and without horizontal and vertical spray-drag effects. At present, the relationship of spray production to surface wind speed is poorly known for hurricane-force wind regimes. Results indicate that spray modifies the hurricane structure in important but complex ways. Spray moistens the near-surface layer through increased evaporation. The effect of spray on the near-surface temperature profile depends on the amount of spray and its location in the hurricane. For moderate spray amounts, the near-surface layer warms within the high-wind region of the hurricane and cools at larger radii. For larger spray amounts, the near-surface layer warms relative to the moderate spray case. The moderate spray simulations (both with and without drag effects) have little net effect on the hurricane intensity. However, in the heavier spray runs, the total sensible heat flux is enhanced by 200 W m−2, while the total latent heat flux is enhanced by over 150 W m−2 in the high-wind region of the storm. Horizontal spray drag decreases wind speeds between 1 and 2 m s−1, and vertical spray drag increases the stability of the lower BL. In these heavy spray runs, the effect of the enhanced spray sensible and latent heat fluxes dominates the negative spray-drag effects, and as a result, the modeled storm intensity is upward of 10 mb stronger than the control run by the end of the simulation time. This study shows that spray has the capability of significantly affecting hurricane structure, but to do so, the amount of spray ejected into the BL of the hurricane would need to lie near the upper end of the currently hypothesized spray-source functions.
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Jeong, Dahai, Brian K. Haus et Mark A. Donelan. « Enthalpy Transfer across the Air–Water Interface in High Winds Including Spray ». Journal of the Atmospheric Sciences 69, no 9 (1 septembre 2012) : 2733–48. http://dx.doi.org/10.1175/jas-d-11-0260.1.
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Abstract Controlled experiments were conducted in the Air–Sea Interaction Saltwater Tank (ASIST) at the University of Miami to investigate air–sea moist enthalpy transfer rates under various wind speeds (range of 0.6–39 m s−1 scaled to equivalent 10-m neutral winds) and water–air temperature differences (range of 1.3°–9.2°C). An indirect calorimetric (heat content budget) measurement technique yielded accurate determinations of moist enthalpy flux over the full range of wind speeds. These winds included conditions with significant spray generation, the concentrations of which were of the same order as field observations. The moist enthalpy exchange coefficient so measured included a contribution from cooled reentrant spray and therefore serves as an upper limit for the interfacial transfer of enthalpy. An unknown quantity of spray was also observed to exit the tank without evaporating. By invoking an air volume enthalpy budget it was determined that the potential contribution of this exiting spray over an unbounded water volume was up to 28%. These two limits bound the total enthalpy transfer coefficient including spray-mediated transfers.
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Rizza, Umberto, Elisa Canepa, Antonio Ricchi, Davide Bonaldo, Sandro Carniel, Mauro Morichetti, Giorgio Passerini, Laura Santiloni, Franciano Scremin Puhales et Mario Miglietta. « Influence of Wave State and Sea Spray on the Roughness Length : Feedback on Medicanes ». Atmosphere 9, no 8 (1 août 2018) : 301. http://dx.doi.org/10.3390/atmos9080301.
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Occasionally, storms that share many features with tropical cyclones, including the presence of a quasi-circular “eye” a warm core and strong winds, are observed in the Mediterranean. Generally, they are known as Medicanes, or tropical-like cyclones (TLC). Due to the intense wind forcings and the consequent development of high wind waves, a large number of sea spray droplets—both from bubble bursting and spume tearing processes—are likely to be produced at the sea surface. In order to take into account this process, we implemented an additional Sea Spray Source Function (SSSF) in WRF-Chem, model version 3.6.1, using the GOCART (Goddard Chemistry Aerosol Radiation and Transport) aerosol sectional module. Traditionally, air-sea momentum fluxes are computed through the classical Charnock relation that does not consider the wave-state and sea spray effects on the sea surface roughness explicitly. In order to take into account these forcing, we implemented a more recent parameterization of the sea surface aerodynamic roughness within the WRF surface layer model, which may be applicable to both moderate and high wind conditions. The implemented SSSF and sea surface roughness parameterization have been tested using an operative model sequence based on COAWST (Coupled Ocean Atmosphere Wave Sediment Transport) and WRF-Chem. The third-generation wave model SWAN (Simulating Waves Nearshore), two-way coupled with the WRF atmospheric model in the COAWST framework, provided wave field parameters. Numerical simulations have been integrated with the WRF-Chem chemistry package, with the aim of calculating the sea spray generated by the waves and to include its effect in the Charnock roughness parametrization together with the sea state effect. A single case study is performed, considering the Medicane that affected south-eastern Italy on 26 September 2006. Since this Medicane is one of the most deeply analysed in literature, its investigation can easily shed some light on the feedbacks between sea spray and drag coefficients.
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Bruch, William, Jacques Piazzola, Hubert Branger, Alexander M. J. van Eijk, Christopher Luneau, Denis Bourras et Gilles Tedeschi. « Sea-Spray-Generation Dependence on Wind and Wave Combinations : A Laboratory Study ». Boundary-Layer Meteorology 180, no 3 (4 juillet 2021) : 477–505. http://dx.doi.org/10.1007/s10546-021-00636-y.
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Ebben, Carlena J., Andrew P. Ault, Matthew J. Ruppel, Olivia S. Ryder, Timothy H. Bertram, Vicki H. Grassian, Kimberly A. Prather et Franz M. Geiger. « Size-Resolved Sea Spray Aerosol Particles Studied by Vibrational Sum Frequency Generation ». Journal of Physical Chemistry A 117, no 30 (22 juillet 2013) : 6589–601. http://dx.doi.org/10.1021/jp401957k.
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Chen, Qianjie, Jessica A. Mirrielees, Sham Thanekar, Nicole A. Loeb, Rachel M. Kirpes, Lucia M. Upchurch, Anna J. Barget et al. « Atmospheric particle abundance and sea salt aerosol observations in the springtime Arctic : a focus on blowing snow and leads ». Atmospheric Chemistry and Physics 22, no 23 (1 décembre 2022) : 15263–85. http://dx.doi.org/10.5194/acp-22-15263-2022.
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Abstract. Sea salt aerosols play an important role in the radiation budget and atmospheric composition over the Arctic, where the climate is rapidly changing. Previous observational studies have shown that Arctic sea ice leads are an important source of sea salt aerosols, and modeling efforts have also proposed blowing snow sublimation as a source. In this study, size-resolved atmospheric particle number concentrations and chemical composition were measured at the Arctic coastal tundra site of Utqiaġvik, Alaska, during spring (3 April–7 May 2016). Blowing snow conditions were observed during 25 % of the 5-week study period and were overpredicted by a commonly used blowing snow parameterization based solely on wind speed and temperature. Throughout the study, open leads were present locally. During periods when blowing snow was observed, significant increases in the number concentrations of 0.01–0.06 µm particles (factor of 6, on average) and 0.06–0.3 µm particles (67 %, on average) and a significant decrease (82 %, on average) in 1–4 µm particles were observed compared to low wind speed periods. These size distribution changes were likely caused by the generation of ultrafine particles from leads and/or blowing snow, with scavenging of supermicron particles by blowing snow. At elevated wind speeds, both submicron and supermicron sodium and chloride mass concentrations were enhanced, consistent with wind-dependent local sea salt aerosol production. At moderate wind speeds below the threshold for blowing snow as well as during observed blowing snow, individual sea spray aerosol particles were measured. These individual salt particles were enriched in calcium relative to sodium in seawater due to the binding of this divalent cation with organic matter in the sea surface microlayer and subsequent enrichment during seawater bubble bursting. The chemical composition of the surface snowpack also showed contributions from sea spray aerosol deposition. Overall, these results show the contribution of sea spray aerosol production from leads on both aerosols and the surface snowpack. Therefore, if blowing snow sublimation contributed to the observed sea salt aerosol, the snow being sublimated would have been impacted by sea spray aerosol deposition rather than upward brine migration through the snowpack. Sea spray aerosol production from leads is expected to increase, with thinning and fracturing of sea ice in the rapidly warming Arctic.
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TAKEDA, Masahide, Kyohei KAWASE, Takaaki SHIGEMATSU, Muneo TSUDA, Takashi HABUCHI et Takahiko AMINO. « Possibility of Sea Spray Generation Process Model When Wave Collides with Vertical Wall ». Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering) 70, no 2 (2014) : I_946—I_950. http://dx.doi.org/10.2208/kaigan.70.i_946.
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MacMahan, Jamie, Ed Thornton, Jessica Koscinski et Qing Wang. « Field Observations and Modeling of Surfzone Sensible Heat Flux ». Journal of Applied Meteorology and Climatology 57, no 6 (juin 2018) : 1371–83. http://dx.doi.org/10.1175/jamc-d-17-0228.1.
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AbstractSurfzone sensible heat flux (HS,SZ) obtained through direct eddy-covariance estimates was measured at four different sandy beach sites along Monterey Bay, California. The HS,SZ source region is estimated from a footprint probability distribution function (pdf) model and is only considered when at least 70% of the footprint pdf occupies the surfzone. The measured HS,SZ is 2 times the modeled interfacial sensible heat (HS,int) using COARE3.5. A formulation for estimating sensible heat flux from spray droplets (HS,spray) generated during depth-limited wave breaking is developed. The sea-spray generation function for droplet radii ranging over 0.1 < ro < 1000 μm is based on self-similar spectra of spray droplets measured from the surfzone forced by the average depth-limited breaking wave dissipation across the surfzone. However, it is shown that the size of the spume droplets that contribute to HS,spray is limited owing to the relatively short residence time in air as the droplets fall to the sea surface during wave breaking. The addition of the surfzone-modeled HS,spray to the COARE3.5 HS,int gives values similar to the observed surfzone HS,SZ, highlighting the importance of depth-limited wave-breaking processes to sensible heat flux. Measured HS,SZ values are an order of magnitude larger than simultaneous open ocean observations.
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Shpund, J., M. Pinsky et A. Khain. « Microphysical Structure of the Marine Boundary Layer under Strong Wind and Spray Formation as Seen from Simulations Using a 2D Explicit Microphysical Model. Part I : The Impact of Large Eddies ». Journal of the Atmospheric Sciences 68, no 10 (1 octobre 2011) : 2366–84. http://dx.doi.org/10.1175/2011jas3652.1.
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Abstract The effects of large eddies (LE) on the marine boundary layer (MBL) microphysics and thermodynamics is investigated using a 2D Lagrangian model with spectral bin microphysics including effects of sea spray. The 600 m × 400 m MBL computational area is covered by 3750 adjacent interacting Lagrangian parcels moving in a turbulent-like flow. A turbulent-like velocity field is designed as a sum of a high number of harmonics with random time-dependent amplitudes and different wavelengths including large eddies with scales of several hundred meters. The model explicitly calculates diffusion growth/evaporation, collisions, and sedimentation of droplets forming both as sea spray droplets and background aerosols, as well as aerosol masses within droplets. The turbulent mixing between parcels is explicitly taken into account. Sea spray generation is determined by a source function depending on the background wind speed assumed in the simulations to be equal to 20 m s−1. The results of simulations obtained by taking into account the effects of LE are compared to those obtained under the assumption that the vertical transport of droplets and passive scalars is caused by small-scale turbulent diffusion. Small-scale turbulence diffusion taken alone leads to an unrealistic MBL structure. Nonlocal mixing of the MBL caused by LE leads to the formation of a well-mixed MBL with a vertical structure close to the observed one. LE lead to an increase in the sensible and latent heat surface fluxes by 50%–100% and transport a significant amount of large spray droplets upward. Microphysical processes lead to formation of spray-induced drizzling clouds with cloud base near the 200-m level.
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Zotova, A. N., Yu I. Troitskaya, D. A. Sergeev et A. A. Kandaurov. « Direct numerical simulation of bag-breakup - mechanism of sea spray generation in strong winds ». Journal of Physics : Conference Series 1163 (février 2019) : 012028. http://dx.doi.org/10.1088/1742-6596/1163/1/012028.
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Yurovsky, Yury Yu, Vladimir N. Kudryavtsev, Semyon A. Grodsky et Bertrand Chapron. « Ka-Band Doppler Scatterometry : A Strong Wind Case Study ». Remote Sensing 14, no 6 (10 mars 2022) : 1348. http://dx.doi.org/10.3390/rs14061348.
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Global joint measurements of sea surface winds and currents are planned using satellite-based Doppler scatterometers operating in the Ka-band to achieve improved spatial resolution and retrieval accuracy. Still, the knowledge of sea surface Ka-band backscatter properties is poor, particularly, at high winds (>20 m s−1). Sea surface radar cross-section in the Ka-band, in contrast to that in the lower frequency Ku-/X-/C-/L-bands, is likely more sensitive to sea spray, small-scale particles typically present at high winds. In this paper, tower-based field data collected by a continuous dual-co-polarized Ka-band radar during a strong offshore wind event (with wind speed reaching 33 m s−1) are analyzed. This katabatic wind event (≈12 h long) was also recorded by supplementary wave, wind, and current sensors. At the wave fetch of ≈1 km, the maximum wavelength of observed offshore waves was ≈10 m. For such extremely young wind–sea conditions, an apparent sea spray generation was observed during wind gusts. Radar measurements were performed at 20∘ and 45∘ incidence angles, mostly for cross- and up-wind azimuth look geometry. Based on these high wind measurements, the previously developed Ka-band empirical model is tested and compared with other published geophysical model functions. Dual-co-polarized measurements are used to infer resonant Bragg and non-Bragg scattering components and assess the short wind wave spectrum, which shows a clear tendency for saturation at high winds. The presence of sea spray signatures is apparent in the high-frequency tails of radar Doppler spectra, but their overall contribution to the Doppler centroid frequency is weak. Hence, the standard modulation transfer function approach developed for moderate winds is still applicable at high winds for interpreting the wave-induced Doppler velocity and inferring sea surface currents. These results can also be useful for understanding Doppler scatterometry measurements in tropical cyclones.
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TAKEDA, Masahide, Kenji Uozumi, Takaaki SHIGEMATSU, Muneo TSUDA, Takashi HABUCHI et Takahiko AMINO. « Fundamental Study on Conditions of Sea Spray Generation when Waves Dashing against a Vertical Wall ». Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering) 67, no 2 (2011) : I_701—I_705. http://dx.doi.org/10.2208/kaigan.67.i_701.
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Andreas, Edgar L. « A New Sea Spray Generation Function for Wind Speeds up to 32 m s−1 ». Journal of Physical Oceanography 28, no 11 (novembre 1998) : 2175–84. http://dx.doi.org/10.1175/1520-0485(1998)028<2175:anssgf>2.0.co;2.
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Reddy, Sandeep K., Raphael Thiraux, Bethany A. Wellen Rudd, Lu Lin, Tehseen Adel, Tatsuya Joutsuka, Franz M. Geiger, Heather C. Allen, Akihiro Morita et Francesco Paesani. « Bulk Contributions Modulate the Sum-Frequency Generation Spectra of Water on Model Sea-Spray Aerosols ». Chem 4, no 7 (juillet 2018) : 1629–44. http://dx.doi.org/10.1016/j.chempr.2018.04.007.
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Kandaurov, Alexander, Daniil Sergeev, Yuliya Troitskaya et Olga Ermakova. « Investigation of the mechanisms of sea spray generation induced by wind-wave interaction in laboratory conditions ». EPJ Web of Conferences 213 (2019) : 02036. http://dx.doi.org/10.1051/epjconf/201921302036.
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The paper presents the results of investigations of the mechanisms of spray of droplets generation within wind wave interaction obtained under laboratory conditions on the High-speed Wind-Wave Flume of the Institute of Applied Physics of the Russian Academy of Sciences. For the research, a multi-angle high-speed video system used together shadow method, including underwater illumination. The results allowed for the classification of mechanismsleading to the formation of droplets. Three main types of phenomena responsible for the generation of the spume droplets near the wave crest were specified: breakage of liquid ligaments, bursting of large submerged bubbles, and bag breakup. The last and less known mechanism claims to be dominant for high wind speeds and it was described in detail.
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Maohua, Zhang, Lv Zhengyi, Cui Jiyin, Tian Zenong et Li Zhiyi. « Durability of Marine Concretes with Nanoparticles under Combined Action of Bending Load and Salt Spray Erosion ». Advances in Materials Science and Engineering 2022 (2 août 2022) : 1–17. http://dx.doi.org/10.1155/2022/1968770.
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The coupling effect of bending load and salt spray erosion during the service of a sea-crossing bridge accelerates the deterioration and durability of concrete and dramatically reduces the load-carrying capacity of the bridge. The effects of nanoparticles on the durability of marine concrete exposed to bending loads and salt spray erosion were studied. In this paper, nano-SiO2 and nano-Fe2O3 were mixed into plain concrete. Free chloride ions (Cl−) were titrated at different concrete depths using a four-point loading device and a self-developed salt spray erosion test chamber. Test results showed that chloride ion levels in the tensile and compressive zones for both nanoconcretes were lower than plain concrete at the same timepoint. The optimal mixtures of the two nanoparticles were 2% and 1%, and the improvement of nano-SiO2 was more significant than nano-Fe2O3. Due to the special properties of nanomaterials, they effectively improved the microstructure of concrete and the composition of cement hydration products. This allowed concrete to become more compact, reduced crack generation, increased the difficulty of Cl− migration inside the concrete, and improved the overall durability of marine concrete upon exposure to bending loads and salt spray erosion.
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Shi, Jun, Jinpei Yan, Shanshan Wang, Shuhui Zhao, Miming Zhang, Suqing Xu, Qi Lin, Hang Yang et Siying Dai. « Cyclones enhance the transport of sea spray aerosols to the high atmosphere in the Southern Ocean ». Atmospheric Chemistry and Physics 23, no 18 (19 septembre 2023) : 10349–59. http://dx.doi.org/10.5194/acp-23-10349-2023.
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Abstract. Cyclones are expected to increase the vertical transport of sea spray aerosols (SSAs), which may significantly impact the climate by increasing the population of cloud condensation nuclei (CCN) and the cloud droplet number concentration (Nd). In this study, a high-time-resolution (1 h) aerosol monitoring was carried out in the middle and high Southern Hemisphere from 23 February to 4 March 2018. The characteristics of SSAs during three cyclones were observed during the cruise. The results showed that SSA level in the low atmosphere did not increase with the wind speed during cyclone processes, which was different from the anticipated scenario that SSA concentration would increase with wind speed. However, the size of SSA particles during cyclones was larger than that in the no-cyclone periods. It seems that the generation of SSAs was enhanced during cyclones, but SSA concentration near the sea surface increased scarcely. The upward-transport proportion was calculated according to the wind stress and sea salt flux between cyclone and non-cyclone periods. It indicated that more than 23.4 % of the SSAs were transported upwards by cyclone processes during event 1, and 36.2 % and 38.9 % were transported upwards in event 2 and event 3, respectively. The upward transport of SSAs was the main reason why SSA concentration did not increase in the low atmosphere. The transport of SSAs to the high atmosphere during cyclones may additionally increase the CCN burden in the marine boundary layer, which may affect the regional climate. This study highlights the importance of SSA transport to the high atmosphere by cyclones and extends the knowledge of SSA generation and the impact factor during the cyclone period in marine atmosphere.
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Pryor, S. C., et L. L. Sørensen. « Nitric Acid–Sea Salt Reactions : Implications for Nitrogen Deposition to Water Surfaces ». Journal of Applied Meteorology 39, no 5 (1 mai 2000) : 725–31. http://dx.doi.org/10.1175/1520-0450-39.5.725.
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Abstract Many previous studies have indicated the importance of nitric acid (HNO3) reactions on sea salt particles for flux divergence of HNO3 in the marine surface layer. The potential importance of this reaction in determining the spatial and temporal patterns of nitrogen dry deposition to marine ecosystems is investigated using models of sea spray generation and particle- and gas-phase dry deposition. Under horizontally homogeneous conditions with near-neutral stability and for wind speeds between 3.5 and 10 m s−1, transfer of HNO3 to the particle phase to form sodium nitrate may decrease the deposition velocity of nitrogen by over 50%, leading to greater horizontal transport prior to deposition to the sea surface. Conversely, for wind speeds above 10 m s−1, transfer of nitrogen to the particle phase would increase the deposition rate and hence decrease horizontal transport prior to surface removal.
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Collins, D. B., D. F. Zhao, M. J. Ruppel, O. Laskina, J. R. Grandquist, R. L. Modini, M. D. Stokes et al. « Direct aerosol chemical composition measurements to evaluate the physicochemical differences between controlled sea spray aerosol generation schemes ». Atmospheric Measurement Techniques 7, no 11 (6 novembre 2014) : 3667–83. http://dx.doi.org/10.5194/amt-7-3667-2014.
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Abstract. Controlled laboratory studies of the physical and chemical properties of sea spray aerosol (SSA) must be under-pinned by a physically and chemically accurate representation of the bubble-mediated production of nascent SSA particles. Bubble bursting is sensitive to the physico-chemical properties of seawater. For a sample of seawater, any important differences in the SSA production mechanism are projected into the composition of the aerosol particles produced. Using direct chemical measurements of SSA at the single-particle level, this study presents an intercomparison of three laboratory-based, bubble-mediated SSA production schemes: gas forced through submerged sintered glass filters ("frits"), a pulsed plunging-waterfall apparatus, and breaking waves in a wave channel filled with natural seawater. The size-resolved chemical composition of SSA particles produced by breaking waves is more similar to particles produced by the plunging waterfall than those produced by sintered glass filters. Aerosol generated by disintegrating foam produced by sintered glass filters contained a larger fraction of organic-enriched particles and a different size-resolved elemental composition, especially in the 0.8–2 μm dry diameter range. Interestingly, chemical differences between the methods only emerged when the particles were chemically analyzed at the single-particle level as a function of size; averaging the elemental composition of all particles across all sizes masked the differences between the SSA samples. When dried, SSA generated by the sintered glass filters had the highest fraction of particles with spherical morphology compared to the more cubic structure expected for pure NaCl particles produced when the particle contains relatively little organic carbon. In addition to an intercomparison of three SSA production methods, the role of the episodic or "pulsed" nature of the waterfall method on SSA composition was under-taken. In organic-enriched seawater, the continuous operation of the plunging waterfall resulted in the accumulation of surface foam and an over-expression of organic matter in SSA particles compared to those produced by a pulsed plunging waterfall. Throughout this set of experiments, comparative differences in the SSA number size distribution were coincident with differences in aerosol particle composition, indicating that the production mechanism of SSA exerts important controls on both the physical and chemical properties of the resulting aerosol with respect to both the internal and external mixing state of particles. This study provides insight into the inextricable physicochemical differences between each of the bubble-mediated SSA generation mechanisms tested and the aerosol particles that they produce, and also serves as a guideline for future laboratory studies of SSA particles.
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Collins, D. B., D. F. Zhao, M. J. Ruppel, O. Laskina, J. R. Grandquist, R. L. Modini, M. D. Stokes et al. « Direct aerosol chemical composition measurements to evaluate the physicochemical differences between controlled sea spray aerosol generation schemes ». Atmospheric Measurement Techniques Discussions 7, no 7 (3 juillet 2014) : 6457–99. http://dx.doi.org/10.5194/amtd-7-6457-2014.
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Abstract. Controlled laboratory studies of the physical and chemical properties of sea spray aerosol (SSA) must be underpinned by a physically and chemically accurate representation of the bubble mediated production of nascent SSA particles. Since bubble bursting is sensitive to the physicochemical properties of seawater, any important differences in the SSA production mechanism are projected into SSA composition. Using direct chemical measurements of SSA at the single-particle level, this study presents an inter-comparison of three laboratory-based, bubble-mediated SSA production schemes: gas forced through submerged sintered glass filters ("frits"), a pulsed plunging waterfall apparatus, and breaking waves in a wave channel filled with natural seawater. The size-resolved chemical composition of SSA particles produced by breaking waves is more similar to particles produced by the plunging waterfall than sintered glass filters. Aerosol generated by disintegrating foam produced by sintered glass filters contained a larger fraction of organic enriched particles and a different size-resolved elemental composition, especially in the 0.8–2 μm size range. These particles, when dried, had more spherical morphologies compared to the more cubic structure expected for pure NaCl particles, which can be attributed to the presence of additional organic carbon. In addition to an inter-comparison of three SSA production methods, the role of the episodic or "pulsed" nature of the waterfall method utilized in this study on SSA composition was undertaken. In organic-enriched seawater, the continuous operation of the plunging waterfall mechanism resulted in the accumulation of surface foam and an over-expression of organic matter in SSA particles compared to pulsed plunging waterfall. Throughout this set of experiments, comparative differences in the SSA number size distribution were coincident with differences in aerosol composition, indicating that the production mechanism of SSA exerts important controls on both the physical and chemical properties of the resulting aerosol. This study provides insight into the physicochemical differences between each of these bubble-mediated SSA generation mechanisms and serves as a guideline for future laboratory studies of SSA particles.
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May, Nathaniel W., Jessica L. Axson, Alexa Watson, Kerri A. Pratt et Andrew P. Ault. « Lake spray aerosol generation : a method for producing representative particles from freshwater wave breaking ». Atmospheric Measurement Techniques 9, no 9 (6 septembre 2016) : 4311–25. http://dx.doi.org/10.5194/amt-9-4311-2016.
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Abstract. Wave-breaking action in bodies of freshwater produces atmospheric aerosols via a similar mechanism to sea spray aerosol (SSA) from seawater. The term lake spray aerosol (LSA) is proposed to describe particles formed by this mechanism, which have been observed over the Laurentian Great Lakes. Though LSA has been identified from size distribution measurements during a single measurement campaign, no measurements of LSA composition or relationship to bubble-bursting dynamics have been conducted. An LSA generator utilizing a plunging jet, similar to many SSA generators, was constructed for the generation of aerosol from freshwater samples and model salt solutions. To evaluate this new generator, bubble and aerosol number size distributions were measured for salt solutions representative of freshwater (CaCO3) and seawater (NaCl) at concentrations ranging from that of freshwater to seawater (0.05–35 g kg−1), synthetic seawater (inorganic), synthetic freshwater (inorganic), and a freshwater sample from Lake Michigan. Following validation of the bubble and aerosol size distributions using synthetic seawater, a range of salt concentrations were investigated. The systematic studies of the model salts, synthetic freshwater, and Lake Michigan sample indicate that LSA is characterized by a larger number size distribution mode diameter of 300 nm (lognormal), compared to seawater at 110 nm. Decreasing salt concentrations from seawater to freshwater led to greater bubble coalescence and formation of larger bubbles, which generated larger particles and lower aerosol number concentrations. This resulted in a bimodal number size distribution with a primary mode (180 ± 20 nm) larger than that of SSA, as well as a secondary mode (46 ± 6 nm) smaller than that of SSA. This new method for studying LSA under isolated conditions is needed as models, at present, utilize SSA parameterizations for freshwater systems, which do not accurately predict the different size distributions observed for LSA or resulting climate properties. Given the abundance of freshwater globally, this potentially important source of aerosol needs to be thoroughly characterized, as the sizes produced are relevant to light scattering, cloud condensation nuclei (CCN), and ice nuclei (IN) concentrations over bodies of freshwater.
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Stokes, M. D., G. B. Deane, K. Prather, T. H. Bertram, M. J. Ruppel, O. S. Ryder, J. M. Brady et D. Zhao. « A Marine Aerosol Reference Tank system as a breaking wave analogue for the production of foam and sea-spray aerosols ». Atmospheric Measurement Techniques 6, no 4 (30 avril 2013) : 1085–94. http://dx.doi.org/10.5194/amt-6-1085-2013.
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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.
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Troitskaya, Yu I., O. S. Ermakova, A. A. Kandaurov, D. S. Kozlov, D. A. Sergeev et S. S. Zilitinkevich. « Fragmentation of the “bag-breakup” type as a mechanism of the generation of sea spray at strong and hurricane winds ». Doklady Earth Sciences 477, no 1 (novembre 2017) : 1330–35. http://dx.doi.org/10.1134/s1028334x17110174.
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Troitskaya, Yuliya, Alexander Kandaurov, Olga Ermakova, Dmitry Kozlov, Anna Zotova et Daniil Sergeev. « The Small-Scale Instability of the Air–Water Interface Responsible for the Bag-Breakup Fragmentation ». Journal of Physical Oceanography 52, no 3 (mars 2022) : 493–517. http://dx.doi.org/10.1175/jpo-d-21-0192.1.
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Abstract The “bag breakup” fragmentation is the dominant mechanism for spume droplet production in high winds, which substantially affects the ocean–atmosphere exchange processes. The amount of droplets ejected from the surface, as well as their typical sizes, is prescribed by the surface wind velocity and fetch. The corresponding empirical correlations were obtained only for the limited parameters of the laboratory environment. The applicability range can be extended through the construction of a theoretical model that describes the initiation of the bag-breakup fragmentation, estimates the fragmenting liquid volume prescribing the droplet sizes, and determines the dependence on the wind parameters. This paper presents such a model. First, we conducted linear stability analysis of small-scale disturbances at the water surface under a high wind; this showed that the small-scale ripples (about 1 cm) propagating against the wind in the surface wind drift following the reference frame grew fast due to the Kelvin–Helmholtz instability, when the wind friction velocity exceeded the threshold of about 1 m s−1. Given the weak dispersion, the nonlinear stage of evolution was addressed using the Riemann simple wave equation modified to describe the increasing disturbances. The analytical solution for the equation suggested the scaling of the volume of liquid undergoing the bag-breakup fragmentation and its dependence on in agreement with the laboratory data. Using the scaling, we calculated the statistics of the bag-breakup fragmentation based on the lognormal size distribution of the fragmenting objects. Significance Statement The “bag breakup” fragmentation is the dominant mechanism for generating spray in hurricane winds. The parameters of spray droplets substantially affect the exchange processes between the ocean and the atmosphere and, thereby, the development of sea storms. The rapid process of spray generation can only be studied in laboratory environments using sophisticated experimental techniques. To apply the laboratory data to field conditions, we need a theoretical model that describes the threshold for fragmentation initiation, the fragmenting liquid volume, which scales the size and number of spray droplets, their dependence on wind parameters, etc. In the present work, we suggest a simple analytical model of the bag-breakup initiation, verify it in the laboratory experiment, and suggest the statistical description of the fragmentation events.
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Richter, David H., Anne E. Dempsey et Peter P. Sullivan. « Turbulent Transport of Spray Droplets in the Vicinity of Moving Surface Waves ». Journal of Physical Oceanography 49, no 7 (juillet 2019) : 1789–807. http://dx.doi.org/10.1175/jpo-d-19-0003.1.
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AbstractA common technique for estimating the sea surface generation functions of spray and aerosols is the so-called flux–profile method, where fixed-height concentration measurements are used to infer fluxes at the surface by assuming a form of the concentration profile. At its simplest, this method assumes a balance between spray emission and deposition, and under these conditions the concentration profile follows a power-law shape. It is the purpose of this work to evaluate the influence of waves on this power-law theory, as well as investigate its applicability over a range of droplet sizes. Large-eddy simulations combined with Lagrangian droplet tracking are used to resolve the turbulent transport of spray droplets over moving, monochromatic waves at the lower surface. The wave age and the droplet diameter are varied, and it is found that droplets are highly influenced both by their inertia (i.e., their inability to travel exactly with fluid streamlines) and the wave-induced turbulence. Deviations of the vertical concentration profiles from the power-law theory are found at all wave ages and for large droplets. The dynamics of droplets within the wave boundary layer alter their net vertical fluxes, and as a result, estimates of surface emission based on the flux–profile method can yield significant errors. In practice, the resulting implication is that the flux–profile method may unsuitable for large droplets, and the combined effect of inertia and wave-induced turbulence is responsible for the continued spread in their surface source estimates.
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Ault, Andrew P., Defeng Zhao, Carlena J. Ebben, Michael J. Tauber, Franz M. Geiger, Kimberly A. Prather et Vicki H. Grassian. « Raman microspectroscopy and vibrational sum frequency generation spectroscopy as probes of the bulk and surface compositions of size-resolved sea spray aerosol particles ». Physical Chemistry Chemical Physics 15, no 17 (2013) : 6206. http://dx.doi.org/10.1039/c3cp43899f.
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Mestayer, Patrice, et Claude Lefauconnier. « Spray droplet generation, transport, and evaporation in a wind wave tunnel during the humidity exchange over the sea experiments in the simulation tunnel ». Journal of Geophysical Research 93, no C1 (1988) : 572. http://dx.doi.org/10.1029/jc093ic01p00572.
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Kaiser, J. C., J. Hendricks, M. Righi, N. Riemer, R. A. Zaveri, S. Metzger et V. Aquila. « The MESSy aerosol submodel MADE3 (v2.0b) : description and a box model test ». Geoscientific Model Development 7, no 3 (17 juin 2014) : 1137–57. http://dx.doi.org/10.5194/gmd-7-1137-2014.
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Abstract. We introduce MADE3 (Modal Aerosol Dynamics model for Europe, adapted for global applications, 3rd generation; version: MADE3v2.0b), an aerosol dynamics submodel for application within the MESSy framework (Modular Earth Submodel System). MADE3 builds on the predecessor aerosol submodels MADE and MADE-in. Its main new features are the explicit representation of coarse mode particle interactions both with other particles and with condensable gases, and the inclusion of hydrochloric acid (HCl) / chloride (Cl) partitioning between the gas and condensed phases. The aerosol size distribution is represented in the new submodel as a superposition of nine lognormal modes: one for fully soluble particles, one for insoluble particles, and one for mixed particles in each of three size ranges (Aitken, accumulation, and coarse mode size ranges). In order to assess the performance of MADE3 we compare it to its predecessor MADE and to the much more detailed particle-resolved aerosol model PartMC-MOSAIC in a box model simulation of an idealised marine boundary layer test case. MADE3 and MADE results are very similar, except in the coarse mode, where the aerosol is dominated by sea spray particles. Cl is reduced in MADE3 with respect to MADE due to the HCl / Cl partitioning that leads to Cl removal from the sea spray aerosol in our test case. Additionally, the aerosol nitrate concentration is higher in MADE3 due to the condensation of nitric acid on coarse mode particles. MADE3 and PartMC-MOSAIC show substantial differences in the fine particle size distributions (sizes &lesssim; 2 μm) that could be relevant when simulating climate effects on a global scale. Nevertheless, the agreement between MADE3 and PartMC-MOSAIC is very good when it comes to coarse particle size distributions (sizes &gtrsim; 2 μm), and also in terms of aerosol composition. Considering these results and the well-established ability of MADE in reproducing observed aerosol loadings and composition, MADE3 seems suitable for application within a global model.
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Kaiser, J. C., J. Hendricks, M. Righi, N. Riemer, R. A. Zaveri, S. Metzger et V. Aquila. « The MESSy aerosol submodel MADE3 (v2.0b) : description and a box model test ». Geoscientific Model Development Discussions 7, no 1 (21 janvier 2014) : 691–739. http://dx.doi.org/10.5194/gmdd-7-691-2014.
Texte intégralRésumé :
Abstract. We introduce MADE3 (Modal Aerosol Dynamics model for Europe, adapted for global applications, 3rd generation), an aerosol dynamics submodel for application within the MESSy framework (Modular Earth Submodel System). MADE3 builds on the predecessor aerosol submodels MADE and MADE-in. Its main new features are the explicit representation of coarse particle interactions both with other particles and with condensable gases, and the inclusion of hydrochloric acid (HCl)/chloride (Cl) partitioning between the gas and condensed phases. The aerosol size distribution is represented in the new submodel as a superposition of nine lognormal modes: one for fully soluble particles, one for insoluble particles, and one for mixed particles in each of three size ranges (Aitken, accumulation, and coarse mode size ranges). In order to assess the performance of MADE3 we compare it to its predecessor MADE and to the much more detailed particle-resolved aerosol model PartMC-MOSAIC in a box model simulation of an idealised marine boundary layer test case. MADE3 and MADE results are very similar, except in the coarse mode, where the aerosol is dominated by sea spray particles. Cl is reduced in MADE3 with respect to MADE due to the HCl/Cl partitioning that leads to Cl removal from the sea spray aerosol in our test case. Additionally, aerosol nitrate concentration is higher in MADE3 due to the condensation of nitric acid on coarse particles. MADE3 and PartMC-MOSAIC show substantial differences in the fine particle size distributions (sizes &lesssim; 2 μm) that could be relevant when simulating climate effects on a global scale. Nevertheless, the agreement between MADE3 and PartMC-MOSAIC is very good when it comes to coarse particle size distribution, and also in terms of aerosol composition. Considering these results and the well-established ability of MADE in reproducing observed aerosol loadings and composition, MADE3 seems suitable for application within a global model.
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Gong, Xianda, Heike Wex, Manuela van Pinxteren, Nadja Triesch, Khanneh Wadinga Fomba, Jasmin Lubitz, Christian Stolle et al. « Characterization of aerosol particles at Cabo Verde close to sea level and at the cloud level – Part 2 : Ice-nucleating particles in air, cloud and seawater ». Atmospheric Chemistry and Physics 20, no 3 (6 février 2020) : 1451–68. http://dx.doi.org/10.5194/acp-20-1451-2020.
Texte intégralRésumé :
Abstract. Ice-nucleating particles (INPs) in the troposphere can form ice in clouds via heterogeneous ice nucleation. Yet, atmospheric number concentrations of INPs (NINP) are not well characterized, and, although there is some understanding of their sources, it is still unclear to what extend different sources contribute or if all sources are known. In this work, we examined properties of INPs at Cabo Verde (a.k.a. Cape Verde) from different environmental compartments: the oceanic sea surface microlayer (SML), underlying water (ULW), cloud water and the atmosphere close to both sea level and cloud level. Both enrichment and depletion of NINP in SML compared to ULW were observed. The enrichment factor (EF) varied from roughly 0.4 to 11, and there was no clear trend in EF with ice-nucleation temperature. NINP values in PM10 sampled at Cape Verde Atmospheric Observatory (CVAO) at any particular ice-nucleation temperature spanned around 1 order of magnitude below −15 ∘C, and about 2 orders of magnitude at warmer temperatures (>-12 ∘C). Among the 17 PM10 samples at CVAO, three PM10 filters showed elevated NINP at warm temperatures, e.g., above 0.01 L−1 at −10 ∘C. After heating samples at 95 ∘C for 1 h, the elevated NINP at the warm temperatures disappeared, indicating that these highly ice active INPs were most likely biological particles. INP number concentrations in PM1 were generally lower than those in PM10 at CVAO. About 83±22 %, 67±18 % and 77±14 % (median±standard deviation) of INPs had a diameter >1 µm at ice-nucleation temperatures of −12, −15 and −18 ∘C, respectively. PM1 at CVAO did not show such elevated NINP at warm temperatures. Consequently, the difference in NINP between PM1 and PM10 at CVAO suggests that biological ice-active particles were present in the supermicron size range. NINP in PM10 at CVAO was found to be similar to that on Monte Verde (MV, at 744 m a.s.l.) during noncloud events. During cloud events, most INPs on MV were activated to cloud droplets. When highly ice active particles were present in PM10 filters at CVAO, they were not observed in PM10 filters on MV but in cloud water samples instead. This is direct evidence that these INPs, which are likely biological, are activated to cloud droplets during cloud events. For the observed air masses, atmospheric NINP values in air fit well to the concentrations observed in cloud water. When comparing concentrations of both sea salt and INPs in both seawater and PM10 filters, it can be concluded that sea spray aerosol (SSA) only contributed a minor fraction to the atmospheric NINP. This latter conclusion still holds when accounting for an enrichment of organic carbon in supermicron particles during sea spray generation as reported in literature.
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Fuentes, E., H. Coe, D. Green et G. McFiggans. « Laboratory-generated primary marine aerosol via bubble-bursting and atomization ». Atmospheric Measurement Techniques Discussions 2, no 5 (29 septembre 2009) : 2281–320. http://dx.doi.org/10.5194/amtd-2-2281-2009.
Texte intégralRésumé :
Abstract. A range of bubble and sea spray aerosol generators has been tested in the laboratory and compared with ocean measurements. We have shown that the method of generation has a significant influence on the properties of the aerosol particles produced. Hence, the validity of a generation system to mimic atmospheric aerosol is dependent on its capacity of generating bubbles and particulate in a realistic manner. A bubble-bursting aerosol generator consisting in the production of bubbles by the impingement of water jets on seawater was shown to best reproduce the real oceanic bubble and aerosol distributions signatures. Two aeration methods and a plunging-water jet system were tested as bubble-bursting aerosol generators for comparison with a standard nebulizer. The methods for aerosol production were evaluated by analysing the bubble spectrum generated by the bubble-bursting systems and the submicron size distribution, hygroscopicity and cloud condensation nucleus activity of the aerosols generated by the different techniques. Significant differences in the bubble spectrum and aerosol properties were observed when using different aerosol generators. The hygroscopicity and cloud condensation nucleus activity of aerosols generated by the different methods were similar when a sample of purely inorganic salts was used as a parent seawater solution; however, significant differences in the aerosol properties were found when biogenic organics were incorporated in the seawater samples. The presence of organics in the aerosol caused suppression of the growth factor at humidities above 75% RH and an increase in the critical supersaturation when compared with the case without organics. Unequal extent of these effects was observed for aerosols generated by the different methods of particle production. While the highest reductions of the growth factor were observed for the plunging-water jet aerosol, the largest effect on the critical supersaturation was obtained for the atomization-generated particles. The results of this work show that the aerosol generation mechanism affects the particles organic enrichment, thus the behaviour of the produced aerosols strongly depends on the laboratory aerosol generator employed.
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Delvigne, Gerard A. L. « EXPERIMENTS ON NATURAL AND CHEMICAL DISPERSION OF OIL IN LABORATORY AND FIELD CIRCUMSTANCES ». International Oil Spill Conference Proceedings 1985, no 1 (1 février 1985) : 507–14. http://dx.doi.org/10.7901/2169-3358-1985-1-507.
Texte intégralRésumé :
ABSTRACT At the Delft Hydraulics Laboratory a laboratory flume has been constructed to aid research into natural and chemically induced dispersion processes as well as to test the effectiveness of dispersant in specific conditions. The flume allows the selection of variables and conditions, for instance, the generation of nonbreaking and breaking waves and currents, the variation of temperature, salinity, oil layer thickness, dispersant spray droplet size, and the droplet impact on the slick surface. The flume has been verified with empirical data gathered from an extensive sea survey on the natural and chemical dispersion of a number of oil slicks. The field experiments on natural dispersion can be modeled satisfactorily in the flume with respect to the formation of oil droplets from the oil slick and the initial intrusion in the water column. The further mixing of oil droplets in the water mass are to be calculated from diffusion theories and other transport processes. Field experiments on the natural and chemical dispersion of 10 artificial oil spills in the North Sea led to the remarkable conclusion that spraying an oil slick with chemical dispersant did not enhance the (natural) dispersion process, while a premixed dispersant in oil was very effective. The ineffectiveness of sprayed dispersant could not be explained from a limited series of experiments performed in the laboratory flume on the effects of evaporation, photo-oxidation, emulsification, and layer thickness on natural and chemical dispersion.