The Experts below are selected from a list of 6705 Experts worldwide ranked by ideXlab platform
Edgar L. Andreas - One of the best experts on this subject based on the ideXlab platform.
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Sea Spray Generation at a Rocky Shoreline
Journal of Applied Meteorology and Climatology, 2016Co-Authors: Edgar L. AndreasAbstract: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...
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Production flux of Sea Spray aerosol
Reviews of Geophysics, 2011Co-Authors: Gerrit De Leeuw, Edgar L. Andreas, Colin D. O'dowd, Christopher W. Fairall, Magdalena D. Anguelova, Ernie R. Lewis, Michael Schulz, Stephen E. SchwartzAbstract:Knowledge of the size- and composition-dependent production flux of primary Sea Spray aerosol (SSA) particles and its dependence on environmental variables is required for modeling cloud microphysical properties and aerosol radiative influences, interpreting measurements of particulate matter in coastal areas and its relation to air quality, and evaluating rates of uptake and reactions of gases in Sea Spray drops. This review examines recent reSearch pertinent to SSA production flux, which deals mainly with production of particles with r 80 (equilibrium radius at 80% relative humidity) less than 1 m and as small as 0.01 m. Production of Sea Spray particles and its dependence on controlling factors has been investigated in laboratory studies that have examined the dependences on water temperature, salinity, and the presence of organics and in field measurements with micrometeorological techniques that use newly developed fast optical particle sizers. Extensive measurements show that water-insoluble organic matter contributes substantially to the composition of SSA particles with r80 < 0.25 m and, in locations with high biological activity, can be the dominant constituent. Order-of-magnitude variation remains in estimates of the size-dependent production flux per white area, the quantity central to formulations of the production flux based on the whitecap method. This variation indicates that the production flux may depend on quantities such as the volume flux of air bubbles to the surface that are not accounted for in current models. Variation in estimates of the whitecap fraction as a function of wind speed contributes additional, comparable uncertainty to production flux estimates. © 2011 by the American Geophysical Union.
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Sea Spray icing of drilling and production platforms
2009Co-Authors: Kathleen F. Jones, Edgar L. AndreasAbstract:Abstract : Because of the observed decrease in the ice cover in the Beaufort and Chukchi Seas, it is possible that Spray icing of rigs used for oil exploration and drilling may be more frequent and possibly more severe in the coming years than it has been in the past. In this report we describe a model for Sea Spray icing on fixed offshore structures. The accretion of small Sea Spray droplets onto two-dimensional structural sections and components depends on the liquid water content of the Spray cloud, as well as wind speed, droplet diameter, and the diameter of the object. The Spray cloud's liquid water content is obtained from the flux of film, jet, and spume droplets from the ocean surface and the vertical velocity of the droplets. The Spray droplet flux increases dramatically with increasing wind speed, as whitecaps cover more of the ocean surface and the wind shears droplets off the wave crests. The more massive larger droplets tend to fall out of the Spray cloud; as a result, the liquid water content decreases with height. We present modeled icing rates for the semi-submersible drilling rigs Ocean Bounty in the winter of 1979-1980 and the Sedco 708 in January 1983. These results are compared to available information on the icing rate or the ice accumulation.
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Sea Spray Impacts on Intensifying Midlatitude Cyclones
Journal of the Atmospheric Sciences, 2005Co-Authors: William Perrie, Edgar L. Andreas, Weiqing Zhang, John R. Gyakum, Ron Mctaggart-cowanAbstract:Abstract Air–Sea transfer processes over the ocean strongly affect how hurricanes develop. High winds generate large amounts of Sea Spray, which can modify the transfer of momentum, heat, and moisture across the air–Sea interface. However, the extent to which Sea Spray can modify extratropical or midlatitude hurricanes and intense cyclones has not been resolved. This paper reports simulations of extratropical Hurricanes Earl (1998) and Danielle (1998) and an intense winter cyclone from January 2000 using a mesoscale atmospheric model and a recent Sea Spray parameterization. These simulations show that Sea Spray can increase the Sea surface heat flux, especially the latent heat flux, in a midlatitude cyclone and that Sea Spray’s impact on cyclone intensity depends on the storm structure and development and is strongest for cyclones with high winds.
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Sea Spray Effects on Surface Heat and Moisture Fluxes
1999Co-Authors: Edgar L. AndreasAbstract:Abstract : The goal is to investigate, theoretically and through analyzing existing data, the role that Sea Spray plays in transferring heat and moisture across the air-Sea interface, especially in high winds. Ultimately, we hope to develop simple parameterizations for these air-Sea fluxes for use in large-scale models, especially those simulating tropical and extra-tropical storms.
Colin D. O'dowd - One of the best experts on this subject based on the ideXlab platform.
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A Sea Spray aerosol flux parameterization encapsulating wave state
Atmospheric Chemistry and Physics, 2014Co-Authors: Jurgita Ovadnevaite, Darius Ceburnis, Astrid Manders, G. De Leeuw, Ciaran Monahan, Antti-ilari Partanen, Hannele Korhonen, Colin D. O'dowdAbstract:Abstract. A new Sea Spray source function (SSSF), termed Oceanflux Sea Spray Aerosol or OSSA, was derived based on in-situ Sea Spray aerosol measurements along with meteorological/physical parameters. Submicron Sea Spray aerosol fluxes derived from particle number concentration measurements at the Mace Head coastal station, on the west coast of Ireland, were used together with open-ocean eddy correlation flux measurements from the Eastern Atlantic Sea Spray, Gas Flux, and Whitecap (SeaSAW) project cruise. In the overlapping size range, the data for Mace Head and SeaSAW were found to be in a good agreement, which allowed deriving the new SSSF from the combined dataset spanning the dry diameter range from 15 nm to 6 μm. The OSSA source function has been parameterized in terms of five lognormal modes and the Reynolds number instead of the more commonly used wind speed, thereby encapsulating important influences of wave height, wind history, friction velocity, and viscosity. This formulation accounts for the different flux relationships associated with rising and waning wind speeds since these are included in the Reynolds number. Furthermore, the Reynolds number incorporates the kinematic viscosity of water, thus the SSSF inherently includes dependences on Sea surface temperature and salinity. The temperature dependence of the resulting SSSF is similar to that of other in-situ derived source functions and results in lower production fluxes for cold waters and enhanced fluxes from warm waters as compared with SSSF formulations that do not include temperature effects.
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Bistable effect of organic enrichment on Sea Spray radiative properties
Geophysical Research Letters, 2013Co-Authors: Aditya Vaishya, Darius Ceburnis, Jurgita Ovadnevaite, Jakub Bialek, S. G. Jennings, Colin D. O'dowdAbstract:[1] Primary-produced Sea Spray aerosol, typically comprising Sea-salt, but also enriched with organic matter (OM) in biologically active oceanic regions, impacts the global radiative budget through contributions to aerosol optical depth. We show that Sea Spray light-scattering enhancement, f(RH), as a function of relative humidity (RH) is suppressed when enriched with OM. A new hygroscopic growth factor parameterization reveals a dual hygroscopicity state, flipping from high hygroscopicity and high f(RH) to low hygroscopicity and low f(RH) as the OM mixing volume percentage exceeds ~ 55% in Sea Spray. Under elevated wind speeds, this affects the Top-of-atmosphere direct radiative forcing (ΔF) by reducing the cooling contribution of Sea Spray by ~ 5.5 times compared to pure Sea-salt Spray. These results suggest a positive feedback coupling between the marine biosphere, Sea Spray aerosol, and the direct radiative budget.
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Marine organics effect on Sea-Spray light scattering
2013Co-Authors: Aditya Vaishya, Darius Ceburnis, Jurgita Ovadnevaite, Jakub Bialek, S. G. Jennings, Colin D. O'dowdAbstract:Primary-produced Sea-Spray is typically composed of Sea-salt, but in biologically-active regions, the Spray can become enriched with organic matter which reduces hygroscopicity of Sea-Spray, thereby having a potential impact on aerosol scattering. This study shows that scattering enhancement of marine aerosol, as a function of increasing relative humidity, is reduced when enriched with organics whose results are used to develop a new hygroscopicity growth-factor parameterization for Sea-Spray enriched in organic matter. The parameterization reveals a dual state which flips from high-hygroscopicity and high-scattering enhancement to low-hygroscopicity and low-scattering enhancement as the organic volume fraction increases from below ∼ 0.55 to above ∼ 0.55. In terms of organic enrichment, the effect on Top of Atmosphere (TOA) direct radiative forcing (ΔF) is to reduce the cooling contribution of Sea-Spray by ∼ 5.5 times compared to pure Sea-salt Spray. The results presented here highlight a significant coup...
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Production flux of Sea Spray aerosol
Reviews of Geophysics, 2011Co-Authors: Gerrit De Leeuw, Edgar L. Andreas, Colin D. O'dowd, Christopher W. Fairall, Magdalena D. Anguelova, Ernie R. Lewis, Michael Schulz, Stephen E. SchwartzAbstract:Knowledge of the size- and composition-dependent production flux of primary Sea Spray aerosol (SSA) particles and its dependence on environmental variables is required for modeling cloud microphysical properties and aerosol radiative influences, interpreting measurements of particulate matter in coastal areas and its relation to air quality, and evaluating rates of uptake and reactions of gases in Sea Spray drops. This review examines recent reSearch pertinent to SSA production flux, which deals mainly with production of particles with r 80 (equilibrium radius at 80% relative humidity) less than 1 m and as small as 0.01 m. Production of Sea Spray particles and its dependence on controlling factors has been investigated in laboratory studies that have examined the dependences on water temperature, salinity, and the presence of organics and in field measurements with micrometeorological techniques that use newly developed fast optical particle sizers. Extensive measurements show that water-insoluble organic matter contributes substantially to the composition of SSA particles with r80 < 0.25 m and, in locations with high biological activity, can be the dominant constituent. Order-of-magnitude variation remains in estimates of the size-dependent production flux per white area, the quantity central to formulations of the production flux based on the whitecap method. This variation indicates that the production flux may depend on quantities such as the volume flux of air bubbles to the surface that are not accounted for in current models. Variation in estimates of the whitecap fraction as a function of wind speed contributes additional, comparable uncertainty to production flux estimates. © 2011 by the American Geophysical Union.
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A combined organic‐inorganic Sea‐Spray source function
Geophysical Research Letters, 2008Co-Authors: Colin D. O'dowd, Baerbel Langmann, Saji Varghese, Claire Scannell, Darius Ceburnis, Maria Cristina FacchiniAbstract:[1] This study presents a novel approach to develop a combined organic-inorganic sub-micron Sea-Spray source function for inclusion in large-scale models. It requires wind speed and surface ocean chlorophyll-a concentration as input parameters. The combined organic-inorganic source function is implemented in the REMOTE regional climate model and Sea-Spray fields are predicted with particular focus on the North East Atlantic. The model predictions using the new source functions compare well with observations of total Sea-Spray mass and organic carbon fraction in Sea-Spray aerosol. During winter (periods of low oceanic biological activity), Sea-salt dominates the Sea-Spray mass while in summer (when biological activity is high), water soluble organic carbon contributes between 60–90% of the submicron Sea-Spray mass.
Lianxin Zhang - One of the best experts on this subject based on the ideXlab platform.
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Impact of Sea Spray and Sea Surface Roughness on the Upper Ocean Response to Super Typhoon Haitang (2005)
Journal of Physical Oceanography, 2021Co-Authors: Lianxin Zhang, William Perrie, Changlong Guan, Chunjian Sun, Xuefeng Zhang, Bo Dan, Kexiu LiuAbstract:AbstractA coupled ocean-wave-Sea Spray model system is used to investigate the impacts of Sea Spray and Sea surface roughness on the response of the upper ocean to the passage of the super typhoon Haitang. Sea Spray mediated heat and momentum fluxes are derived from an improved version of Fairall’s heat fluxes formulation (Zhang et al., 2017) and Andreas’s Sea Spray-mediated momentum flux models. For winds ranging from low to extremely high speeds, a new parameterization scheme for the Sea surface roughness is developed, in which the effects of wave state and Sea Spray are introduced. In this formulation, the drag coefficient has minimal values over the right quadrant of the typhoon track, along which the typhoon-generated waves are longer, smoother, and older, compared to other quadrants. Using traditional interfacial air-Sea turbulent (sensible, latent, and momentum) fluxes, the Sea surface cooling response to typhoon Haitang is overestimated by 1 °C, which can be compensated by the effects of Sea Spray and ocean waves on the right side of the storm. Inclusion of Sea Spray-mediated turbulent fluxes and Sea surface roughness, modulated by ocean waves, gives enhanced cooling along the left edges of the cooling area by 0.2 °C, consistent with the upper ocean temperature observations.
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Impact of Sea Spray on the Yellow and East China Seas thermal structure during the passage of Typhoon Rammasun (2002)
Journal of Geophysical Research: Oceans, 2017Co-Authors: Lianxin Zhang, Changlong Guan, Xuefeng Zhang, Peter C. Chu, Guofang Chao, Guijun HanAbstract:Strong winds lead to large amounts of Sea Spray in the lowest part of the atmospheric boundary layer. The Spray droplets affect the air-Sea heat fluxes due to their evaporation and the momentum due to the change of Sea surface, and in turn change the upper ocean thermal structure. In this study, impact of Sea Spray on upper ocean temperatures in the Yellow and East China Seas (YES) during typhoon Rammasun's passage is investigated using the POMgcs ocean model with a Sea Spray parameterization scheme, in which the Sea Spray-induced heat fluxes are based on an improved Fairall's Sea Spray heat fluxes algorithm, and the Sea Spray-induced momentum fluxes are derived from an improved COARE version 2.6 bulk model. The distribution of the Sea Spray mediated turbulent fluxes was primarily located at Rammasun eye-wall region, in accord with the maximal wind speeds regions. When Rammasun enters the Yellow Sea, the Sea Spray mediated latent (sensible) heat flux maximum is enhanced by 26% (13.5%) compared to that of the interfacial latent (sensible) heat flux. The maximum of the total air-Sea momentum fluxes is enhanced by 43% compared to the counterpart of the interfacial momentum flux. Furthermore, the Sea Spray plays a key role in enhancing the intensity of the typhoon-induced “cold suction” and “heat pump” processes. When the effect of Sea Spray is considered, the maximum of the Sea surface cooling in the right side of Rammasun's track is increased by 0.5°C, which is closer to the available satellite observations.
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Impact of Sea Spray on upper ocean temperature during typhoon passage: simulation with a 1-D turbulent model
Chinese Journal of Oceanology and Limnology, 2015Co-Authors: Lianxin Zhang, Chunjian Sun, Xuefeng Zhang, Guijun Han, Xiaojian Cui, Caixia Shao, Xiaoshuang Zhang, Xidong WangAbstract:At the interface between the lower atmosphere and Sea surface, Sea Spray might significantly influence air-Sea heat fluxes and subsequently, modulate upper ocean temperature during a typhoon passage. The effects of Sea Spray were introduced into the parameterization of Sea surface roughness in a 1-D turbulent model, to investigate the effects of Sea Spray on upper ocean temperature in the Kuroshio Extension area, for the cases of two real typhoons from 2006, Yagi and Soulik. Model output was compared with data from the Kuroshio Extension Observatory (KEO), and Reynolds and AMSRE satellite remote sensing Sea surface temperatures. The results indicate drag coefficients that include the Spray effect are closer to observations than those without, and that Sea Spray can enhance the heat fluxes (especially latent heat flux) considerably during a typhoon passage. Consequently, the model results with heat fluxes enhanced by Sea Spray simulate better the cooling process of the SST and upper-layer temperature profiles. Additionally, results from the simulation of the passage of typhoon Soulik (that passed KEO quickly), which included the Sea Spray effect, were better than for the simulated passage of typhoon Yagi (that crossed KEO slowly). These promising 1-D results could provide insight into the application of Sea Spray in general circulation models for typhoon studies.
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Upper Ocean Thermal Responses to Sea Spray Mediated Turbulent Fluxes during Typhoon Passage
Advances in Meteorology, 2015Co-Authors: Lianxin Zhang, Changlong Guan, Chunjian Sun, Siyu GaoAbstract:A one-dimensional turbulent model is used to investigate the effect of Sea Spray mediated turbulent fluxes on upper ocean temperature during the passage of typhoon Yagi over the Kuroshio Extension area in 2006. Both a macroscopical Sea Spray momentum flux algorithm and a microphysical heat and moisture flux algorithm are included in this turbulent model. Numerical results show that the model can well reproduce the upper ocean temperature, which is consistent with the data from the Kuroshio Extension Observatory. Besides, the Sea surface temperature is decreased by about 0.5°C during the typhoon passage, which also agrees with the Sea surface temperature dataset derived from Advanced Microwave Scanning Radiometer for the Earth Observing and Reynolds. Diagnostic analysis indicates that Sea Spray acts as an additional source of the air-Sea turbulent fluxes and plays a key role in increasing the turbulent kinetic energy in the upper ocean, which enhances the temperature diffusion there. Therefore, Sea Spray is also an important factor in determining the upper mixed layer depth during the typhoon passage.
Darius Ceburnis - One of the best experts on this subject based on the ideXlab platform.
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A Sea Spray aerosol flux parameterization encapsulating wave state
Atmospheric Chemistry and Physics, 2014Co-Authors: Jurgita Ovadnevaite, Darius Ceburnis, Astrid Manders, G. De Leeuw, Ciaran Monahan, Antti-ilari Partanen, Hannele Korhonen, Colin D. O'dowdAbstract:Abstract. A new Sea Spray source function (SSSF), termed Oceanflux Sea Spray Aerosol or OSSA, was derived based on in-situ Sea Spray aerosol measurements along with meteorological/physical parameters. Submicron Sea Spray aerosol fluxes derived from particle number concentration measurements at the Mace Head coastal station, on the west coast of Ireland, were used together with open-ocean eddy correlation flux measurements from the Eastern Atlantic Sea Spray, Gas Flux, and Whitecap (SeaSAW) project cruise. In the overlapping size range, the data for Mace Head and SeaSAW were found to be in a good agreement, which allowed deriving the new SSSF from the combined dataset spanning the dry diameter range from 15 nm to 6 μm. The OSSA source function has been parameterized in terms of five lognormal modes and the Reynolds number instead of the more commonly used wind speed, thereby encapsulating important influences of wave height, wind history, friction velocity, and viscosity. This formulation accounts for the different flux relationships associated with rising and waning wind speeds since these are included in the Reynolds number. Furthermore, the Reynolds number incorporates the kinematic viscosity of water, thus the SSSF inherently includes dependences on Sea surface temperature and salinity. The temperature dependence of the resulting SSSF is similar to that of other in-situ derived source functions and results in lower production fluxes for cold waters and enhanced fluxes from warm waters as compared with SSSF formulations that do not include temperature effects.
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Bistable effect of organic enrichment on Sea Spray radiative properties
Geophysical Research Letters, 2013Co-Authors: Aditya Vaishya, Darius Ceburnis, Jurgita Ovadnevaite, Jakub Bialek, S. G. Jennings, Colin D. O'dowdAbstract:[1] Primary-produced Sea Spray aerosol, typically comprising Sea-salt, but also enriched with organic matter (OM) in biologically active oceanic regions, impacts the global radiative budget through contributions to aerosol optical depth. We show that Sea Spray light-scattering enhancement, f(RH), as a function of relative humidity (RH) is suppressed when enriched with OM. A new hygroscopic growth factor parameterization reveals a dual hygroscopicity state, flipping from high hygroscopicity and high f(RH) to low hygroscopicity and low f(RH) as the OM mixing volume percentage exceeds ~ 55% in Sea Spray. Under elevated wind speeds, this affects the Top-of-atmosphere direct radiative forcing (ΔF) by reducing the cooling contribution of Sea Spray by ~ 5.5 times compared to pure Sea-salt Spray. These results suggest a positive feedback coupling between the marine biosphere, Sea Spray aerosol, and the direct radiative budget.
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Marine organics effect on Sea-Spray light scattering
2013Co-Authors: Aditya Vaishya, Darius Ceburnis, Jurgita Ovadnevaite, Jakub Bialek, S. G. Jennings, Colin D. O'dowdAbstract:Primary-produced Sea-Spray is typically composed of Sea-salt, but in biologically-active regions, the Spray can become enriched with organic matter which reduces hygroscopicity of Sea-Spray, thereby having a potential impact on aerosol scattering. This study shows that scattering enhancement of marine aerosol, as a function of increasing relative humidity, is reduced when enriched with organics whose results are used to develop a new hygroscopicity growth-factor parameterization for Sea-Spray enriched in organic matter. The parameterization reveals a dual state which flips from high-hygroscopicity and high-scattering enhancement to low-hygroscopicity and low-scattering enhancement as the organic volume fraction increases from below ∼ 0.55 to above ∼ 0.55. In terms of organic enrichment, the effect on Top of Atmosphere (TOA) direct radiative forcing (ΔF) is to reduce the cooling contribution of Sea-Spray by ∼ 5.5 times compared to pure Sea-salt Spray. The results presented here highlight a significant coup...
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wind speed dependent size resolved parameterization for the organic mass fraction of Sea Spray aerosol
Atmospheric Chemistry and Physics, 2011Co-Authors: B. Gantt, Darius Ceburnis, Matteo Rinaldi, N. Meskhidze, M. C. Facchini, Colin D OdowdAbstract:For oceans to be a significant source of primary organic aerosol (POA), Sea Spray aerosol (SSA) must be highly enriched with organics relative to the bulk Seawater. We propose that organic enrichment at the air-Sea interface, chemical composition of Seawater, and the aerosol size are three main parameters controlling the organic mass fraction of Sea Spray aerosol (OM SSA ). To test this hypothesis, we developed a new marine POA emission function based on a conceptual relationship between the organic enrichment at the air-Sea interface and surface wind speed. The resulting parameterization is explored using aerosol chemical composition and surface wind speed from Atlantic and Pacific coastal stations, and satellite-derived ocean concentrations of chlorophyll- a , dissolved organic carbon, and particulate organic carbon. Of all the parameters examined, a multi-variable logistic regression revealed that the combination of 10 m wind speed and surface chlorophyll- a concentration ([Chl- a ]) are the most consistent predictors of OM SSA . This relationship, combined with the published aerosol size dependence of OM SSA , resulted in a new parameterization for the organic mass fraction of SSA. Global emissions of marine POA are investigated here by applying this newly-developed relationship to existing Sea Spray emission functions, satellite-derived [Chl- a ], and modeled 10 m winds. Analysis of model simulations shows that global annual submicron marine organic emission associated with Sea Spray is estimated to be from 2.8 to 5.6 Tg C yr −1 . This study provides additional evidence that marine primary organic aerosols are a globally significant source of organics in the atmosphere.
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A combined organic‐inorganic Sea‐Spray source function
Geophysical Research Letters, 2008Co-Authors: Colin D. O'dowd, Baerbel Langmann, Saji Varghese, Claire Scannell, Darius Ceburnis, Maria Cristina FacchiniAbstract:[1] This study presents a novel approach to develop a combined organic-inorganic sub-micron Sea-Spray source function for inclusion in large-scale models. It requires wind speed and surface ocean chlorophyll-a concentration as input parameters. The combined organic-inorganic source function is implemented in the REMOTE regional climate model and Sea-Spray fields are predicted with particular focus on the North East Atlantic. The model predictions using the new source functions compare well with observations of total Sea-Spray mass and organic carbon fraction in Sea-Spray aerosol. During winter (periods of low oceanic biological activity), Sea-salt dominates the Sea-Spray mass while in summer (when biological activity is high), water soluble organic carbon contributes between 60–90% of the submicron Sea-Spray mass.
Changlong Guan - One of the best experts on this subject based on the ideXlab platform.
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Impact of Sea Spray and Sea Surface Roughness on the Upper Ocean Response to Super Typhoon Haitang (2005)
Journal of Physical Oceanography, 2021Co-Authors: Lianxin Zhang, William Perrie, Changlong Guan, Chunjian Sun, Xuefeng Zhang, Bo Dan, Kexiu LiuAbstract:AbstractA coupled ocean-wave-Sea Spray model system is used to investigate the impacts of Sea Spray and Sea surface roughness on the response of the upper ocean to the passage of the super typhoon Haitang. Sea Spray mediated heat and momentum fluxes are derived from an improved version of Fairall’s heat fluxes formulation (Zhang et al., 2017) and Andreas’s Sea Spray-mediated momentum flux models. For winds ranging from low to extremely high speeds, a new parameterization scheme for the Sea surface roughness is developed, in which the effects of wave state and Sea Spray are introduced. In this formulation, the drag coefficient has minimal values over the right quadrant of the typhoon track, along which the typhoon-generated waves are longer, smoother, and older, compared to other quadrants. Using traditional interfacial air-Sea turbulent (sensible, latent, and momentum) fluxes, the Sea surface cooling response to typhoon Haitang is overestimated by 1 °C, which can be compensated by the effects of Sea Spray and ocean waves on the right side of the storm. Inclusion of Sea Spray-mediated turbulent fluxes and Sea surface roughness, modulated by ocean waves, gives enhanced cooling along the left edges of the cooling area by 0.2 °C, consistent with the upper ocean temperature observations.
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Numerical simulation study of Sea Spray’s effect on tropical cyclone——a case study of typhoon “Megi”
2021Co-Authors: Jialin Zhang, Wenqing Zhang, Haofeng Xia, Changlong GuanAbstract:<p>Sea Spray has important influence on the evolution of tropical cyclone. The influence of Sea Spray in the numerical simulation and prediction of tropical cyclones is not ignorable. In order to explore the kinetic and thermodynamic effects of Sea Spray on tropical cyclone, the drag coefficient C<sub>D </sub>and the enthalpy transfer coefficient C<sub>K</sub> with Sea Spray&#8217;s effects were included in the coupled ocean-atmosphere-wave-sediment transport modeling system (COAWST). The numerical results show that, the effect of Sea Spray can effectively improve the simulation results of tropical cyclone path. When only the kinetic effect of Sea Spray is considered, the momentum flux at the surface of Sea is little affected, and the upward sensible heat flux and latent heat flux are slightly increased. When kinetic and thermodynamic effects of Sea Spray is considered at the same time, the momentum flux is slightly increased, the upward sensible heat flux is increased, and the latent heat flux is significantly increased, the intensity of tropical cyclone is significantly enhanced, mainly due to the thermodynamic effect . Considering the kinetic and thermodynamic effects of Sea Spray at the same time is more effective than considering the kinetic effects of Sea Spray in improving the intensity simulation of tropical cyclone.</p>
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The estimation of Sea Spray at wind speeds ranging from light to extreme
2021Co-Authors: Joey Voermans, Alexander Babanin, Changlong GuanAbstract:<p>As one of typical elements in the air-Sea boundary layer, Sea Spray is expected to mediate energy flux exchange in the air and ocean boundary layers, and therefore it is of crucial importance to the meteorology, oceanology, and regional climatology. In addition, the Spray is also considered as one of the missing physical mechanisms in atmospheric and oceanic numerical models. Hence, it is necessary to accurately predict how much Sea Spray is produced at the air-Sea boundary layer. Though Spray has been studied for a number of decades, large uncertainties still linger. For instance, uncertainties in qualifying how much Spray is produced on the Sea surface reach 10<sup>6</sup> times. This is because of the rarity of Spray observations in the field, especially under strong wind condition.</p><p>To give a reliable Spray production model, scientists tried to employ laser-based facilities in the field to observe Sea Spray by interpreting infrared laser-beam intensity into Sea Spray volume flux over the water surface. Hence, in the current study, we collected datasets in the field measured by laser-based facilities on the North-West Shelf of the coast of Western Australia, thereafter, further analyzed, and calibrated them through a series of academic, statistical, and physical analysis to ensure the data quality. After that, assuming the existence of Spray drops in the air-Sea layer would attenuate the infrared laser-beam intensity, the weakening extends of laser-beam intensity is used to estimate the volume flux of Sea Spray above the ocean surface at winds speed ranging from light to extreme during the passage of Tropical Cyclone Olwyn (2015). It should be noted that our observations of Sea Spray volume flux are within the ranges of existing models and are consistent with the model proposed by Andreas (1992) in both trend and magnitude.</p><p>Using the field observations of the Sea Spray volume flux, a Sea Spray volume flux model can be constructed. Given that Sea Spray droplets are generated at the ocean surface through breaking waves and wind shear, the Sea Spray volume flux is expected to be dominated by the properties of the local wind and wave field. For physical consistency across the wide range of scales observed in the field and laboratory, non-dimensional parameters (i.e., non-dimensional wind speed and the mean wave steepness) were adopted to construct the model. Consequently, a power-law non-dimensional Spray volumetric flux model is suggested based on the estimation of the Spray volume flux. It should be noted that one sensitive test was conducted to substantiate the inclusion of wave breaking process, here simply included with the mean wave steepness, improves Spray volume flux parameterization.</p>
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Impact of Sea Spray on the Yellow and East China Seas thermal structure during the passage of Typhoon Rammasun (2002)
Journal of Geophysical Research: Oceans, 2017Co-Authors: Lianxin Zhang, Changlong Guan, Xuefeng Zhang, Peter C. Chu, Guofang Chao, Guijun HanAbstract:Strong winds lead to large amounts of Sea Spray in the lowest part of the atmospheric boundary layer. The Spray droplets affect the air-Sea heat fluxes due to their evaporation and the momentum due to the change of Sea surface, and in turn change the upper ocean thermal structure. In this study, impact of Sea Spray on upper ocean temperatures in the Yellow and East China Seas (YES) during typhoon Rammasun's passage is investigated using the POMgcs ocean model with a Sea Spray parameterization scheme, in which the Sea Spray-induced heat fluxes are based on an improved Fairall's Sea Spray heat fluxes algorithm, and the Sea Spray-induced momentum fluxes are derived from an improved COARE version 2.6 bulk model. The distribution of the Sea Spray mediated turbulent fluxes was primarily located at Rammasun eye-wall region, in accord with the maximal wind speeds regions. When Rammasun enters the Yellow Sea, the Sea Spray mediated latent (sensible) heat flux maximum is enhanced by 26% (13.5%) compared to that of the interfacial latent (sensible) heat flux. The maximum of the total air-Sea momentum fluxes is enhanced by 43% compared to the counterpart of the interfacial momentum flux. Furthermore, the Sea Spray plays a key role in enhancing the intensity of the typhoon-induced “cold suction” and “heat pump” processes. When the effect of Sea Spray is considered, the maximum of the Sea surface cooling in the right side of Rammasun's track is increased by 0.5°C, which is closer to the available satellite observations.
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Derivation of a wave-state-dependent Sea Spray generation function and its application in estimating Sea Spray heat flux
Science China Earth Sciences, 2015Co-Authors: Bin Liu, Changlong Guan, Lian Xie, Dongliang ZhaoAbstract:A Sea Spray generation function (SSGF) for bubble-derived droplets that takes into account the impact of wave state on white-cap coverage was presented in this study. By combining the new SSGF with a previous wave-state-dependent SSGF for spume droplets, an SSGF applicable to both bubble-derived and spume droplets that includes the impacts of wave state was obtained. The produced SSGF varies with surface wind as well as with wave development. As Sea surface wind increases, more Sea Spray droplets are produced, resulting in larger SSGFs and volume fluxes. Meanwhile, under the same wind conditions, the SSGF is mediated by wave state, with larger SSGFs corresponding to older waves and larger windSea Reynolds numbers. The impact of wave state on Sea Spray heat flux was then estimated by applying this SSGF while considering the thermodynamic feedback process. Under given atmospheric and oceanic conditions, the estimated Sea Spray heat flux increases with wind speed, wave age, and windSea Reynolds number.
