Sea spray droplets are produced by waves breaking on the sea surface, and they vary the transfer of energy between the atmosphere and ocean. The sea spray generation function(SSGF) is generally considered as a functio...Sea spray droplets are produced by waves breaking on the sea surface, and they vary the transfer of energy between the atmosphere and ocean. The sea spray generation function(SSGF) is generally considered as a function of the initial radius of the spray droplets and the wind speed. However, ocean waves always exist at the air-sea interface, so it is not reasonable to consider only the effect of sea surface winds while ignoring the effects of ocean waves. Whitecap coverage is an important characteristic parameter of breaking waves, and researchers believe that this parameter is related to both wave state and wind speed. In this paper, the SSGF is parameterized by the whitecap coverage, and a new SSGF describing different droplet radii is organically integrated based on the whitecap coverage parameter. Then, with the relationship between the whitecap coverage and wave state, the influence of ocean waves on the SSGF for different wave states was analyzed by using observational data in the laboratory. The results show that the new SSGF that considers wave effects can reasonably describe the droplet generation process under different wave state conditions.展开更多
Sea spray induced by surface wave breaking plays an important role in air-sea flux.However,large differences in sea spray generation at the same wind speed were presented in previous studies.As a result,the parameteri...Sea spray induced by surface wave breaking plays an important role in air-sea flux.However,large differences in sea spray generation at the same wind speed were presented in previous studies.As a result,the parameterizations of sea spray generation functions can reach 4 orders difference.Wind speed may not be enough to explain this difference,and the surface wave state is a significant factor that causes this large difference,which then affects the estimation of the air-sea heat fluxes.In this study,synchronous observations of air-sea heat fluxes,surface waves and sea spray were conducted at a tower-based platform in a coastal region.Results showed that the sea spray generation is strongly correlated with both wind speed,and wave age as previously;more importantly,wind-wave alignment angle can cause approximately 1.3 orders(or 20 times)of sea spray generation function(SSGF)difference.A new SSGF with a dimensionless parameter RB0.7β-1cosθwas proposed.Heat fluxes caused by sea spray can be comparable to interfacial heat fluxes even at moderate wind speed.The three parameters of sea spray(α=6.4,σ=16,γ=6.3)were optimally fitted and evaluated.The air-sea heat flux evaluated in droplet evaporation layer(DEL)was improved with the new scheme,especially for sensible heat flux.The new parameters should be more suitable than other widely used parameters in numerical simulations.展开更多
A sea spray generation function(SSGF)for bubble-derived droplets that takes into account the impact of wave state on whitecap coverage was presented in this study.By combining the new SSGF with a previous wave-state-d...A sea spray generation function(SSGF)for bubble-derived droplets that takes into account the impact of wave state on whitecap 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.展开更多
A bubble-derived Sea Spray Generation Function （SSGF） was deduced, which was integrated into the new wave-dependent SSGF. The effect of sea spray feedback was parameterized by the feedback coefficients A and B. The ...A bubble-derived Sea Spray Generation Function （SSGF） was deduced, which was integrated into the new wave-dependent SSGF. The effect of sea spray feedback was parameterized by the feedback coefficients A and B. The relationship of A（B） and the wind-sea Reynolds number was derived, which shows that the feedback effect of sea spray is decreasing with the wave developing. New sea spray flux formulae, including the new SSGF and new feedback coefficients, were proposed, which can reveal clearly the influence of wave state on sea spray fluxes. Spray fluxes in the Humidity Exchange Over the Sea （HEXOS） experiment were simulated again, and results show that spray momentum flux is small in this experiment, but spray heat flux is large. Comparisons of the sea spray fluxes calculated by two kinds of formulae in different wave states show that previous wave-independent spray flux formulae are the special cases of the presented new wave dependent formulae for sea spray flnx.展开更多
基金The National Natural Science Foundation of China under contract No.41676014。
文摘Sea spray droplets are produced by waves breaking on the sea surface, and they vary the transfer of energy between the atmosphere and ocean. The sea spray generation function(SSGF) is generally considered as a function of the initial radius of the spray droplets and the wind speed. However, ocean waves always exist at the air-sea interface, so it is not reasonable to consider only the effect of sea surface winds while ignoring the effects of ocean waves. Whitecap coverage is an important characteristic parameter of breaking waves, and researchers believe that this parameter is related to both wave state and wind speed. In this paper, the SSGF is parameterized by the whitecap coverage, and a new SSGF describing different droplet radii is organically integrated based on the whitecap coverage parameter. Then, with the relationship between the whitecap coverage and wave state, the influence of ocean waves on the SSGF for different wave states was analyzed by using observational data in the laboratory. The results show that the new SSGF that considers wave effects can reasonably describe the droplet generation process under different wave state conditions.
基金supported by the National Natural Science Foundation of China(Grant Nos.42276024,42076014)the Basic Scientific Fund for National Public Research Institutes of China(Grant No.2024S02)。
文摘Sea spray induced by surface wave breaking plays an important role in air-sea flux.However,large differences in sea spray generation at the same wind speed were presented in previous studies.As a result,the parameterizations of sea spray generation functions can reach 4 orders difference.Wind speed may not be enough to explain this difference,and the surface wave state is a significant factor that causes this large difference,which then affects the estimation of the air-sea heat fluxes.In this study,synchronous observations of air-sea heat fluxes,surface waves and sea spray were conducted at a tower-based platform in a coastal region.Results showed that the sea spray generation is strongly correlated with both wind speed,and wave age as previously;more importantly,wind-wave alignment angle can cause approximately 1.3 orders(or 20 times)of sea spray generation function(SSGF)difference.A new SSGF with a dimensionless parameter RB0.7β-1cosθwas proposed.Heat fluxes caused by sea spray can be comparable to interfacial heat fluxes even at moderate wind speed.The three parameters of sea spray(α=6.4,σ=16,γ=6.3)were optimally fitted and evaluated.The air-sea heat flux evaluated in droplet evaporation layer(DEL)was improved with the new scheme,especially for sensible heat flux.The new parameters should be more suitable than other widely used parameters in numerical simulations.
基金supported by the National Natural Science Foundation of China(Grant Nos.40830959,41276010,41221063 and 40921004)Ministry of Science and Technology of China(Grant No.2011BAC03B01)+1 种基金US National Oceanic and Atmospheric Administration(NOAA)Climate Change Program via a subcontract(Grant No.UF-EIES-1100031-NCS)from University of FloridaUS Integrated Ocean Observing System(IOOS)Southeast Coastal Ocean Observing Regional Association(SECOORA)through Award#NA11NOS0120033&CFDA#11-012
文摘A sea spray generation function(SSGF)for bubble-derived droplets that takes into account the impact of wave state on whitecap 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.
基金supported by the National Natural Science Foundation of China (Grant Nos. 40490263,40676014)the National Basic Research Program of China (973 Program, Grant No. 2005CB422301)
文摘A bubble-derived Sea Spray Generation Function （SSGF） was deduced, which was integrated into the new wave-dependent SSGF. The effect of sea spray feedback was parameterized by the feedback coefficients A and B. The relationship of A（B） and the wind-sea Reynolds number was derived, which shows that the feedback effect of sea spray is decreasing with the wave developing. New sea spray flux formulae, including the new SSGF and new feedback coefficients, were proposed, which can reveal clearly the influence of wave state on sea spray fluxes. Spray fluxes in the Humidity Exchange Over the Sea （HEXOS） experiment were simulated again, and results show that spray momentum flux is small in this experiment, but spray heat flux is large. Comparisons of the sea spray fluxes calculated by two kinds of formulae in different wave states show that previous wave-independent spray flux formulae are the special cases of the presented new wave dependent formulae for sea spray flnx.
