Optimal Power-Law Description of Oceanic Whitecap Coverage Dependence on Wind Speed

Monahan, Edward C.; Muircheartaigh, Iognáid Ó

doi:10.1175/1520-0485(1980)010<2094:opldoo>2.0.co;2

Cited by 457 publications

(392 citation statements)

References 0 publications

Supporting

Mentioning

374

Contrasting

Order By: Relevance

“…Over the leads the fetch of the open water is usually so small that whitecaps form only at wind speeds >20 m s À1 . Hence the usual parameterization of the whitecap cover as function of wind speed [Monahan and O'Muircheartaigh, 1980] (equation (2)) cannot be used for the leads. Following Nilsson et al [2001], the primary marine aerosol flux in this condition is reduced by an order of magnitude.…”

Section: Comparison With Field Measurements and Other Flux Parameterimentioning

confidence: 99%

See 1 more Smart Citation

Laboratory simulations and parameterization of the primary marine aerosol production

et al. 2003

View full text Add to dashboard Cite

[1] A major source of the primary marine aerosol is the bursting of air bubbles produced by breaking waves. Several source parameterizations are available from the literature, usually limited to particles with a dry diameter D p > 1 mm. The objective of this work is to extend the current knowledge to submicrometer particles. Bubbles were generated in synthetic seawater using a sintered glass filter, with a size spectra that are only partly the same spectra as measured in the field. Bubble spectra, and size distributions of the resulting aerosol (0.020-20.0 mm D p ) of the resulting aerosol, were measured for different salinity, water temperature (T w ), and bubble flux. The spectra show a minimum at $1 mm D p , which separates two modes, one at $0.1 mm, with the largest number of particles, and one at 2.5 mm D p . The modes show different behavior with the variation of salinity and water temperature. When the water temperature increases, the number concentration N p decreases for D p < 0.07 mm, whereas for D p > 0.35 mm, N p increases. The salinity effect suggests different droplet formation processes for droplets smaller and larger than 0.2 mm D p . The number of particles produced per size increment, time unit, and whitecap surface (È) is described as a linear function of T w and a polynomial function of D p . Combining È with the whitecap coverage fraction W (in percent), an expression results for the primary marine aerosol source flux dF 0 /dlogD p = W È (m À2 s À1 ). The results are compared with other commonly used formulations as well as with recent field observations. Implications for aerosol-induced effects on climate are discussed.

show abstract

Section: Comparison With Field Measurements and Other Flux Parameterimentioning

confidence: 99%

“…A commonly used formulation for the source function [Monahan et al, 1986] is based on laboratory observations of dF/dr 0 and empirical relations for the whitecap cover (W in percent) as a function of the wind speed [Monahan and O'Muircheartaigh, 1980]:…”

Section: Introductionmentioning

confidence: 99%

Laboratory simulations and parameterization of the primary marine aerosol production

et al. 2003

View full text Add to dashboard Cite

show abstract

“…To provide a consistent basis for this comparison, the source fluxes (number of particles produced per ocean surface area per second) were converted to production efficiencies (number of particles produced per bubble film cap area). Particle fluxes were divided by the fractional coverage of whitecap area on the sea surface [Monahan and Muircheartaigh, 1980] in order to obtain particle fluxes per whitecap area, F wc (m À2 s À1 ). Assuming that F wc is independent of time and that the time evolution of a whitecap of initial area A 0 is well represented by a simple exponential decay model with time constant t, then equation 3 gives the total number of particles produced from the whitecap over its lifetime.…”

Section: Comparison With Previous Bubble-produced Aerosol Studiesmentioning

confidence: 99%

Effect of soluble surfactant on bubble persistence and bubble‐produced aerosol particles

et al. 2013

View full text Add to dashboard Cite

[1] The effect of soluble surfactant on the persistence of salt-water bubbles and their ability to produce aerosol particles upon bursting was investigated. Ensembles of individual, millimetric bubbles were produced in NaCl solutions of varying surfactant concentration. Aerosol production efficiency-a fundamental property of single bubbles defined as the number of particles produced per bubble film cap area-decreased by 79% to 98% following the addition of surfactant and increase in solution film pressure from 1-2 to 7-27 mN m À1 . The generated particle size distributions (0.01-10 mm dry diameter) contained up to three modes and did not change much for film pressures up to 13.8 mN m À1 . The persistence of the bubbles at the water surface and the thickness of their film caps were investigated with high-speed videography. Addition of soluble surfactant increased average bubble persistence providing more time for the bubbles to drain and thin out with the aid of marginal regeneration flows. Bubble film cap thicknesses ranged from around 1 mm for relatively clean, short-lived bubbles to less than 0.1 mm for surfactant-stabilized, persistent bubbles. The suppression of aerosol production from the surfactant-stabilized bubbles may have resulted from the dramatic thinning of their caps or reduced surface forces at high film pressure. Previously reported Sea Spray Aerosol source functions were compared to measured aerosol production efficiencies and found to be significantly greater in magnitude, suggesting that there is a source of particles from whitecaps that was not captured in these single-bubble experiments.

show abstract

“…Whereas the statistical study of the probability of wave breaking has been fully developed [32,33]. Recently, the criterions of the wave breaking are the geometrical criterion, kinematic criterion and dynamic criterion, which can be transformed into each other with mathematical derivation.…”

Section: Wedge-like Breaking Wavementioning

confidence: 99%

“…In order to verify the breaker distribution in this paper, the simulated coverage with slope criterion is compared with the Breaker coverage versus wind speed. measured coverage and the empirical results from Monahan and Muircheartaigh [33] in Figure 2. Due to the agreements of the simulated coverage with experimental data and empirical formula, η = 0.586 proves to be reasonable.…”

Section: Wedge-like Breaking Wavementioning

confidence: 99%

Investigation of Low-Grazing-Angle Microwave Backscattering From Threedimensional Breaking Sea Waves

Luo¹,

Zhang²,

Wang³

et al. 2011

PIER

View full text Add to dashboard Cite

Abstract-The microwave backscattering of the sea surface is investigated with the wedge-shaped breaking waves for the super events at low grazing angles (LGA). According to the relationship between the wave breaking and the whitecap, the finite three-dimensional wedges are utilized to approximately model the breaking waves, of which the spatial distribution is simulated with whitecap coverage. The phasemodified two-scale method (TSM) and method of equivalent currents (MEC) are used to calculate the surface and volume scattering of sea surface and breaking waves respectively. The sea spikes in LGA are observed by this model, and the strong directionality is caused by the breakers. Considering the Bragg phase velocity, orbital motion of facets and wind drift, the Doppler spectrum is simulated with the time series of sea clutter. Included the breaking waves, the scattering model indicates that the enhanced non-Bragg scattering leads to the extended Doppler spectrum width. The numerical results agree with the measured data well at LGA. Compared with the statistical models, the complex physical mechanism of the sea scattering is explicitly described in this paper.

show abstract

Optimal Power-Law Description of Oceanic Whitecap Coverage Dependence on Wind Speed

Cited by 457 publications

References 0 publications

Laboratory simulations and parameterization of the primary marine aerosol production

Laboratory simulations and parameterization of the primary marine aerosol production

Effect of soluble surfactant on bubble persistence and bubble‐produced aerosol particles

Investigation of Low-Grazing-Angle Microwave Backscattering From Threedimensional Breaking Sea Waves

Contact Info

Product

Resources

About