Comparison of the spectral-angular properties of light scattered in the Baltic Sea and oil emulsions

Freda, Włodzimierz

doi:10.2971/jeos.2014.14017

Cited by 8 publications

(8 citation statements)

References 27 publications

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“…The scattering phase function of natural seawater is taken from measurements of Freda et al (2007). which were parameterized according to Freda (2014). Although the optical properties of the oil dispersion were determined for multiple wavelengths, Monte Carlo modelling was performed for three wavelengths only, for which phase functions of seawater were known.…”

Section: Modelling Of Light Penetration Within Seawatermentioning

confidence: 99%

The effect of dispersed Petrobaltic oil droplet size on photosynthetically active radiation in marine environment

Haule

Freda

2015

Environ Sci Pollut Res

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Oil pollution in seawater, primarily visible on sea surface, becomes dispersed as an effect of wave mixing as well as chemical dispersant treatment, and forms spherical oil droplets. In this study, we examined the influence of oil droplet size of highly dispersed Petrobaltic crude on the underwater visible light flux and the inherent optical properties (IOPs) of seawater, including absorption, scattering, backscattering and attenuation coefficients. On the basis of measured data and Mie theory, we calculated the IOPs of dispersed Petrobaltic crude oil in constant concentration, but different log-normal size distributions. We also performed a radiative transfer analysis, in order to evaluate the influence on the downwelling irradiance Ed, remote sensing reflectance Rrs and diffuse reflectance R, using in situ data from the Baltic Sea. We found that during dispersion, there occurs a boundary size distribution characterized by a peak diameter d0 = 0.3 μm causing a maximum E d increase of 40% within 0.5-m depth, and the maximum Ed decrease of 100% at depths below 5 m. Moreover, we showed that the impact of size distribution on the "blue to green" ratios of Rrs and R varies from 24% increase to 27% decrease at the same crude oil concentration.

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Section: Modelling Of Light Penetration Within Seawatermentioning

confidence: 99%

The effect of dispersed Petrobaltic oil droplet size on photosynthetically active radiation in marine environment

Haule

Freda

2015

Environ Sci Pollut Res

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“…The influence of oil-in-water emulsion 25 on the absorption coefficient of seawater was researched by Otremba (2007) as well as Haule and Freda (2016), while the influence on scattering properties has been tested by Freda (2014). The consequence of changes in IOPs for remote detection of oil-in-water emulsion has been discussed by Otremba et al (2013);Otremba (2016); Haule et al (2017).…”

Section: Measurements Of Iops In Southern Balticmentioning

confidence: 99%

“…Algae cells, depending on the composition of their pigments, may have a minimum of absorption in a wide range of spectral bands from 550nm to 660nm (Bricaud et al, 2004). But taking into account absorption of water that grows with wavelength (Pope and Fry,20 1997), the minimum is in the spectral band of 555nm.…”

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confidence: 99%

Seasonal variability of upwelling radiance polarization over the Southern Baltic surface

Freda

2017

Preprint

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Abstract. Polarization of light may be used to improve the remote colour sensing of sea water. This can be done in a number of ways, such as limiting of sun glints, obtaining information about atmospheric aerosol properties for atmospheric correction as well as improving the interpretation of the water-leaving signal results. However polarization signals at the top of atmosphere (ToA), that include the water-leaving signal, is strongly influenced by atmospheric molecular scattering and by direct sun and sky reflections from sea surface. For these reasons, it is necessary to better understand the factors that change the polarization of 5 light in the atmosphere-ocean system. In this paper, the influence of seasonal variability of inherent optical properties (IOPs), wind speed and solar zenith angle (SZA) on the polarization of upwelling radiance over the sea surface is discussed. The presented results come from Monte Carlo simulations, which used averaged measurements of IOPs, collected for several years, as input data. The effects of simulations are presented in the form of polar plots of the upwelling radiance degree of polarization (DoP). The results indicate that regardless of the wavelength and type of water, the highest value of the above water DoP is 10 strongly correlated with the absorption-to-attenuation ratio. The correlation is a power function and it depends on both the SZA and the wind speed. The correlation versatility for different wavelengths is very unusual in optics of the sea and is therefore worth emphasizing.

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“…We assumed that crude oil dispersed in marine environment presents most commonly a log-normal size distribution [28]- [30]. We applied the formula given by Jonasz and Fournier [31]:…”

Section: Optical Properties Of Seawater Polluted By Dispersed Oilmentioning

confidence: 99%

Light penetration in seawater polluted by dispersed oil: results of radiative transfer modelling

Haule

Darecki

Toczek

2015

J. Eur. Opt. Soc.-Rapid Publ.

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The downwelling light in seawater is shaped by natural seawater constituents as well as by some external substances which can occur locally and temporally. In this study we focused on dispersed oil droplets which can be found in seawater after an oil spill or in the consequence of intensive shipping, oil extraction and transportation. We applied our modified radiative transfer model based on Monte Carlo code to evaluate the magnitude of potential influence of dispersed oil droplets on the downwelling irradiance and the depth of the euphotic zone. Our model was validated on the basis of in situ measurements for natural (unpolluted) seawater in the Southern Baltic Sea, resulting in less than 5% uncertainty. The optical properties of dispersed Petrobaltic crude oil were calculated on the basis of Mie theory and involved into radiative transfer model. We found that the changes in downwelling light caused by dispersed oil depend on several factors such as oil droplet concentration, size distribution, and the penetration depth (i.e. vertical range of oil droplets occurrence below sea surface). Petrobaltic oil droplets of submicron sizes and penetration depth of 5 m showed a potentially detectable reduction in the depth of the euphotic zone of 5.5% at the concentration of only 10 ppb. Micrometer-sized droplets needed 10 times higher concentration to give a similar effect. Our radiative transfer model provided data to analyse and discuss the influence of each factor separately. This study contributes to the understanding of the change in visible light penetration in seawater affected by dispersed oil.

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Comparison of the spectral-angular properties of light scattered in the Baltic Sea and oil emulsions

Cited by 8 publications

References 27 publications

The effect of dispersed Petrobaltic oil droplet size on photosynthetically active radiation in marine environment

The effect of dispersed Petrobaltic oil droplet size on photosynthetically active radiation in marine environment

Seasonal variability of upwelling radiance polarization over the Southern Baltic surface

Light penetration in seawater polluted by dispersed oil: results of radiative transfer modelling

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