Field validation of wave-wind-dependent sea spray generation functions

2021 ◽  
Author(s):  
William Bruch ◽  
Jacques Piazzola ◽  
Hubert Branger ◽  
Alexander M. J. van Eijk ◽  
Christopher Luneau ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Wave ◽  
Aerosol Concentration ◽  
Sea Surface ◽  
Atmospheric Environment ◽  
Sea Spray ◽  
Marine Aerosol ◽  
Geophysical Research ◽  
Wave Characteristics ◽  
The North

<p>Recent studies stress the importance of considering sea surface wave characteristics in sea spray generation functions (SSGFs). To this end, the effect of interacting winds and waves on sea spray generation was studied using data collected during the Marine Aerosol Tunnel Experiments (MATE2019) conducted at the OSU-Pytheas large wind-wave tunnel facility at Luminy, Marseille (France) (Study detailed in Bruch et al., in review). A total of 20 wind and wave combinations were tested, with wind speeds between 8 and 20 m s<sup>-1 </sup>combined with pure wind waves and waves generated by a wavemaker, allowing for a range of wave characteristics and wave ages. Similar wind speed profiles and whitecapping behavior between the laboratory and the field suggest that the laboratory is appropriate for the study of sea spray production. The sea spray generation flux was estimated from logarithmic vertical sea spray concentration profiles using a flux-profile method using Monin and Obukhov (1954) theory. Results show that the production of larger droplets at 20-35 µm radius is well correlated with the wave slope variance <S<sup>2</sup>>, whilst the wind friction velocity cubed u<sub>*</sub><sup>3 </sup>performs best over 7-20 µm. Two SSGFs are proposed. <br><br>The original work presented here is an assessment of the validity of the two SSGFs in the field. The two laboratory-derived SSGFs are tested in two numerical models; the stationary Marine Aerosol Concentration Model (MACMod) (used in Laussac et al., 2018), and the non-hydrostatic mesocale atmospheric model Meso-NH (jointly developed by the LA - UMR 5560 - and the CNRM - UMR 3589). The <S<sup>2</sup>> necessary required by both SSGFs is estimated using a wind-dependent formulation (Cox and Munk, 1956) and a spectral spectral model (Elfouhaily et al., 1997). Results show that the numerical simulations offer good results relative to sea spray measurements obtained in the North-West Mediterranean in fetch-limited conditions (Laussac et al., 2018), as well as other existing SSGFs in the literature. These results suggest that wind-wave tunnel facilities present an interesting alternative for determining the sea spray generation flux, especially in high wind speed conditions in which deployment in the field is difficult.</p><p>References :<br><br>Bruch, W., Piazzola, J., Branger, H., van Eijk, A. M. J., Luneau, C., Bourras, D., Tedeschi, G. (In review). Sea Spray Generation Dependence on Wind and Wave Combinations : A Laboratory Study. Submitted in : <em>Boundary Layer Meteorology</em>.</p><p>Cox, C., & Munk, W. (1956). Slopes of the sea surface deduced from photographs of sun glitter. <em>University of California Press</em>. Vol. 6,9,401-488.</p><p>Elfouhaily, T., Chapron, B., Katsaros, K., & Vandemark, D. (1997). A unified directional spectrum for long and short wind driven waves. <em>Journal of Geophysical Research: Oceans</em>, <em>102</em>(C7),15781-15796.<br><br>Monin, A. S., & Obukhov, A. M. (1954). Basic laws of turbulent mixing in the surface layer of the atmosphere. Contrib. Geophys. Inst. Acad. Sci. USSR,151(163),e187.<br><br>Laussac, S., Piazzola, J., Tedeschi, G., Yohia, C., Canepa, E., Rizza, U., & Van Eijk, A. M. J. (2018). Development of a fetch dependent sea-spray source function using aerosol concentration measurements in the North-Western Mediterranean. Atmospheric Environment,193,177-189.</p>

scholarly journals Effect of wind speed on the size distribution of biogenic gel particles in the sea surface microlayer: Insights from a wind wave channel experiment

2017 ◽  
Author(s):  
Cui-Ci Sun ◽  
Martin Sperling ◽  
Anja Engel
Keyword(s):  
Wind Speed ◽  
Size Distribution ◽  
Wind Wave ◽  
Sea Surface ◽  
Surface Microlayer ◽  
Wind Speeds ◽  
Wave Channel ◽  
Gel Particles ◽  
Sea Surface Microlayer ◽  
Physical And Chemical

Abstract. Biogenic gels particles, such as transparent exopolymer particles (TEP) and Coomassie stainable particles (CSP), are important components in the sea-surface microlayer (SML). The accumulation of gel particles in the SML and their potential implications for gas exchange and emission of primary organic aerosols have generated considerable research interest in recent years. Changes in the particle-size distribution (PSD) can provide important information for the understanding of physical and chemical processes involving gel particles, such as aggregation, degradation or loss. So far, little is known regarding the influence of wind speed on the size distribution of marine gel particles in the surface microlayer. Here, we present results on the effect of different wind speeds on the PSD of TEP and CSP during a wind wave channel experiment in the Aeolotron. Total area of TEP and CSP were exponentially related to wind speed in the SML. At wind speeds  8 m s−1 also significantly altered the PSD slope of TEP in the 2–16 μm size range toward smaller size. Changes in spectral slopes at wind speeds > 8 m s−1 were more pronounced for TEP than for CSP indicating a high aggregation potential for TEP in the SML, potentially enhancing the export of TEP by aggregates settling out of the SML. Our experiment provided evidence for the control of wind speed on the accumulation of biogenic gel particles and their PSD changes, providing a useful insight into particle dynamics and biophysical processes at the interface between air and sea.

scholarly journals Factors driving the seasonal and hourly variability of sea-spray aerosol number in the North Atlantic

2019 ◽  
Vol 116 (41) ◽  
pp. 20309-20314 ◽  
Author(s):  
Georges Saliba ◽  
Chia-Li Chen ◽  
Savannah Lewis ◽  
Lynn M. Russell ◽  
Laura-Helena Rivellini ◽  
...  
Keyword(s):  
Wind Speed ◽  
North Atlantic ◽  
Climate Models ◽  
Marine Boundary Layer ◽  
Phytoplankton Bloom ◽  
Cloud Condensation Nuclei ◽  
Sea Spray ◽  
Wind Speeds ◽  
The North ◽  
Sea Spray Aerosol

Four North Atlantic Aerosol and Marine Ecosystems Study (NAAMES) field campaigns from winter 2015 through spring 2018 sampled an extensive set of oceanographic and atmospheric parameters during the annual phytoplankton bloom cycle. This unique dataset provides four seasons of open-ocean observations of wind speed, sea surface temperature (SST), seawater particle attenuation at 660 nm (cp,660, a measure of ocean particulate organic carbon), bacterial production rates, and sea-spray aerosol size distributions and number concentrations (NSSA). The NAAMES measurements show moderate to strong correlations (0.56 < R < 0.70) between NSSA and local wind speeds in the marine boundary layer on hourly timescales, but this relationship weakens in the campaign averages that represent each season, in part because of the reduction in range of wind speed by multiday averaging. NSSA correlates weakly with seawater cp,660 (R = 0.36, P << 0.01), but the correlation with cp,660, is improved (R = 0.51, P < 0.05) for periods of low wind speeds. In addition, NAAMES measurements provide observational dependence of SSA mode diameter (dm) on SST, with dm increasing to larger sizes at higher SST (R = 0.60, P << 0.01) on hourly timescales. These results imply that climate models using bimodal SSA parameterizations to wind speed rather than a single SSA mode that varies with SST may overestimate SSA number concentrations (hence cloud condensation nuclei) by a factor of 4 to 7 and may underestimate SSA scattering (hence direct radiative effects) by a factor of 2 to 5, in addition to overpredicting variability in SSA scattering from wind speed by a factor of 5.

Wave- and Anemometer-Based Sea Surface Wind (WASWind) for Climate Change Analysis*

2011 ◽  
Vol 24 (1) ◽  
pp. 267-285 ◽  
Author(s):  
Hiroki Tokinaga ◽  
Shang-Ping Xie
Keyword(s):  
Wind Speed ◽  
Wave Height ◽  
Wind Wave ◽  
Surface Wind ◽  
Sea Surface ◽  
Upward Trend ◽  
Data Set ◽  
Climate Trend ◽  
Sea Surface Wind ◽  
Trend Pattern

Abstract Ship-based measurements of sea surface wind speed display a spurious upward trend due to increases in anemometer height. To correct this bias, the authors constructed a new sea surface wind dataset from ship observations of wind speed and wind wave height archived in the International Comprehensive Ocean–Atmosphere Data Set (ICOADS). The Wave- and Anemometer-based Sea surface Wind (WASWind) dataset is available for wind velocity and scalar speed at monthly resolution on a 4° × 4° longitude–latitude grid from 1950 to 2008. It substantially reduces the upward trend in wind speed through height correction for anemometer-measured winds, rejection of spurious Beaufort winds, and use of estimated winds from wind wave height. The reduced global upward trend is smallest among the existing global datasets of in situ observations and comparable with those of reanalysis products. Despite the significant reduction of globally averaged wind speed trend, WASWind features rich spatial structures in trend pattern, making it a valuable dataset for studies of climate changes on regional scales. Not only does the combination of ship winds and wind wave height successfully reproduce major modes of seasonal-to-decadal variability; its trend patterns are also physically consistent with sea level pressure (SLP) measurements. WASWind is in close agreement with wind changes in satellite measurements by the Special Sensor Microwave Imagers (SSM/Is) for the recent two decades. The agreement in trend pattern with such independent observations illustrates the utility of WASWind for climate trend analysis. An application to the South Asian summer monsoon is presented.

Remote impact of North Atlantic sea surface temperature errors in sub‐seasonal forecasts

2021 ◽  
Author(s):  
Chris Roberts ◽  
Frederic Vitart ◽  
Magdalena Balmaseda
Keyword(s):  
North Atlantic ◽  
Gulf Stream ◽  
Positive Impact ◽  
Ocean Waves ◽  
Sea Surface ◽  
Time Range ◽  
Seasonal Forecasts ◽  
Geophysical Research ◽  
The North ◽  
The North Atlantic

&lt;p&gt;The ECMWF sub-seasonal forecast model includes dynamic representations of the atmosphere, ocean, sea-ice, and ocean-waves. Coupling to a dynamic ocean model allows more a realistic representation of air-sea interaction, but also introduces the potential for systematic errors in sea surface temperatures (SST). Here, we show that North Atlantic SST biases associated with errors in the position of the Gulf Stream have a significant impact on initialized forecasts at the sub&amp;#8208;seasonal time range. Correcting these errors with an online SST bias&amp;#8208;correction scheme improves the mean state of the North Atlantic region and has a significant positive impact on forecasts of atmospheric circulation anomalies. Improvements to forecast skill extend beyond the North Atlantic into Europe and along the northern hemisphere subtropical waveguide. These impacts provide important evidence for the potential benefits to initialized coupled forecast systems of higher&amp;#8208;resolution ocean models that can better resolve the position of the Gulf Stream.&lt;/p&gt;&lt;p&gt;Reference: Roberts, C. D., Vitart, F., &amp; Balmaseda, M. A. Hemispheric impact of North Atlantic SSTs in sub&amp;#8208;seasonal forecasts. Geophysical Research Letters, e2020GL091446.&lt;/p&gt;

Laboratory investigation of air-sea momentum transfer under severe wind conditions

2020 ◽  
Author(s):  
Maksim Vdovin ◽  
Georgy Baydakov ◽  
Daniil Sergeev ◽  
Yuliya Troitskaya
Keyword(s):  
Wind Speed ◽  
Data Processing ◽  
Drag Coefficient ◽  
Financial Support ◽  
Water Surface ◽  
Wind Wave ◽  
Aerodynamic Resistance ◽  
Sea Surface ◽  
Surface Drag ◽  
Wave Flume

&lt;p&gt;Wind-wave interaction at extreme wind speed is of special interest now in connection with the problem of explanation of the sea surface drag saturation at the wind speed exceeding 30 m/s. Now it is established that at hurricane wind speed the sea surface drag coefficient is significantly reduced in comparison with the parameterization obtained at moderate to strong wind conditions.&lt;/p&gt;&lt;p&gt;The subject of this work is investigation of aerodynamic resistance of the waved water surface under severe wind conditions (up to U10 &amp;#8776; 50 m/s). Laboratory experiments were carried out at the new high-speed wind-wave flume in the Large Thermally Stratified Tank (at the Institute of Applied Physics, Russia) built in 2019. The main difference between the new wind-wave flume and the old one is the absence of a pressure gradient along the main axis of the new flume. Aerodynamic resistance of the water surface was measured by the profile method with Pitot tube. A method for data processing taking into account the self-similarity of the air flow velocity profile in the aerodynamic tube was applied for retrieving wind friction velocity and surface drag coefficients. Simultaneously with the airflow velocity measurements, the wind-wave field parameters in the flume were investigated by system of wire gauges.&lt;/p&gt;&lt;p&gt;Analysis of the wind velocity profiles and wind-wave spectra showed tendency to decrease for surface drag coefficient for wind speed exceeding 25 m/s simultaneously with the mean square slope and significant wave height.&lt;/p&gt;&lt;p&gt;&lt;span&gt;Acknowledgments&lt;/span&gt; &lt;br&gt;This work was carried out with the financial support of the RFBR according to the research project 18-55-50005, 20-05-00322, 18-35-20068, 18-05-00265. Data processing was carried out with the financial support of Russian Science Foundation grant 19-17-00209.&lt;/p&gt;

scholarly journals Regional Dependence of Atmospheric Responses to Oceanic Eddies in the North Pacific Ocean

2020 ◽  
Vol 12 (7) ◽  
pp. 1161 ◽  
Author(s):  
Jinlin Ji ◽  
Jing Ma ◽  
Changming Dong ◽  
John Chiang ◽  
Dake Chen
Keyword(s):  
Wind Speed ◽  
Pacific Ocean ◽  
North Pacific ◽  
North Pacific Ocean ◽  
Surface Wind ◽  
Surface Wind Speed ◽  
Sea Surface ◽  
The North ◽  
Oceanic Eddies ◽  
The North Pacific

Based on sea surface height anomaly (SSHA) from satellite altimeter and microwave radiometer datasets, this study investigates atmospheric responses to oceanic eddies in four subdomains of the North Pacific Ocean with strongest eddy activity: Kuroshio Extension (KE), Subtropical Front (SF), California Coastal Current (CC) and Aleutian Islands (AI). Analyses show that anticyclonic eddies cause sea surface temperature, surface wind speed and precipitation rate to increase in all four subdomains, and vice versa. Through a further examination of the regional dependence of atmospheric responses to oceanic eddies, it is found that the strongest and the weakest surface wind speed responses (in winter and summer) are observed in the KE and AI region, respectively. For precipitation rate, seasonal variation of the atmospheric responses to oceanic eddies is strongest in winter and weakest in summer in the KE, CC and AI regions, but stronger in summer in the SF area. The reasons for such regional dependence and seasonality are the differences in the strength of SST anomalies, the vertical kinetic energy flux and atmospheric instability in the four subdomains.

scholarly journals Primary marine aerosol emissions: size resolved eddy covariance measurements with estimates of the sea salt and organic carbon fractions

2007 ◽  
Vol 7 (5) ◽  
pp. 13345-13400 ◽  
Author(s):  
E. D. Nilsson ◽  
E. M. Mårtensson ◽  
J. S. Van Ekeren ◽  
G. de Leeuw ◽  
M. Moerman ◽  
...  
Keyword(s):  
Wind Speed ◽  
Organic Carbon ◽  
Eddy Covariance ◽  
Sea Salt ◽  
Sea Spray ◽  
Marine Aerosol ◽  
Particle Counter ◽  
Wind Speeds ◽  
Sea Salt Aerosol ◽  
Aerosol Emissions

Abstract. Primary marine aerosol fluxes were measured using eddy covariance (EC), a condensation particle counter (CPC) and an optical particle counter (OPC) with a heated inlet. The later was used to discriminate between sea salt and total aerosol. Measurements were made from the 25 m tower at the research station Mace Head at the Irish west coast, May to September 2002. The aerosol fluxes were dominated by upward fluxes, sea spray from bubble bursting at the ocean surface. The sea salt aerosol number emissions increased two orders of magnitude with declining diameter from 1 to 0.1 μm where it peaked at values of 105 to 107 particles m−2s−1. The sea salt emissions increased at all sizes in the wind range 4 to 22 ms−1, in consistency with a power function of the wind speed. The sea salt emission data were compared to three recent sub micrometer sea salt source parameterisations. The best agreement was with Mårtensson et al. (2003), which appear to apply from 0.1 to 1.1 μm diameters in temperate water (12°C) as well as tropical water (25°C). The total aerosol emissions were independent of the wind speed below 10 ms−1, but increased with the wind above 10 ms−1. The aerosol volume emissions were larger for the total aerosol than for the sea salt at all wind speeds, while the sea salt number emissions approached the total number emissions at 15 ms−1. It is speculated that this is caused by organic carbon in the surface water that is depleted at high wind speeds. The data are consistent with an internal aerosol mixture of sea salt, organic carbon and water. Using the aerosol model by Ellison et al. (1999) (a mono-layer of organic carbon surrounding a water-sea-salt brine) we show that the total and sea salt aerosol emissions are consistent. This predict that the organic carbon fraction increase with decreasing diameter from a few % at 1 μm over 50% at about 0.5 μm to about 90% at 0.1 μm, in consistency with simultaneous chemical data by Cavalli et al. (2004). The combined models of Mårtensson et al. (2003) and Ellison et al. (1999) reproduce the observed total aerosol emissions and offer an approach to model the organic sea spray fraction.

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