Wyniki wyszukiwania - BazTech

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Relationships between inherent optical properties in the Baltic Sea for application to the underwater imaging problem

Levin I., Darecki M., Sagan S., Radomyslskaya T.

Oceanologia

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2013

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No. 55 (1)

11-26

EN

Statistical relationships between coefficients of light attenuation, scattering and backscattering at wavelength 550 nm derived from series of optical measurements performed in Baltic Sea waters are presented. The relationships were derived primarily to support data analysis from underwater imaging systems. Comparison of these relations with analogous empirical data from the Atlantic and Pacific Oceans shows that the two sets of relationships are similar, despite the different water types and the various experimental procedures and instrumentation applied. The apparently universal character of the relationships enables an approximate calculation of other optical properties and subsequently of the contrast, signal/noise ratio, visibility range and spatial resolution of underwater imaging systems based on attenuation coefficients at wavelength 550 nm only.

2

Annual spatio-temporal variation of the euphotic depth in the SW-Finnish archipelago, Baltic Sea

Luhtala H., Tolvanen H., Kalliola R.

Oceanologia

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2013

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No. 55 (2)

359-373

EN

We measured depth profiles of underwater PAR (photosynthetically active radiation) together with optically derived turbidity and chlorophyll fluorescence values at 11 sampling stations in the South-West Finnish archipelago of the Baltic Sea. The data were collected eight times during the spring, summer and early autumn of 2010. The results illustrate complex and multidimensional variations in the euphotic depth, which was subject to fourfold and twofold differences in the geographical and seasonal dimensions respectively. The spatio-temporal inconsistency and non-linearity of the seasonal euphotic depth variation calls for further studies at different spatial and temporal scales.

3

Light attenuation in multiphase medium

Król T.

Turbulence : international journal

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2005

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Vol. 11

161-167

EN

Light interaction with optically inhomogeneous media, which generally are multiphase media, must be regarded as interaction with optically turhid media. If the medium scatters mildly and the influence of the energy scattered once more can be neglected, then we deal with a single scattering model. The analysis of light interaction with inhomogeneous media, which usually multiphase media are, requires detailed determination of optical parameters of existing non-homogeneities. One of them is the light attenuation cross-section, which is defined as a sum of light absorption and scattering cross-sections. In order to illustrate a number of effects, which characterize light interaction with multiphase media, optical properties of exemplary multiphase media containing spherical particles are presented (air bubbles in water, emulsions of crude oil in water, phytoplankton cells in water).

4

Osłabianie światła w wodzie z jednogatunkowym zakwitem glonów Scenedesmus obliquus

Pawlak B., Mielnik J.

Zeszyty Naukowe. Acta Physica / Uniwersytet Szczeciński

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1998

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Nr 9

107-119

EN

Results of laboratory investigation of attenuation of light with wavelength in the range 260-900 nm in destilled water with onespiecies flourishment of Scendesmus obliquus algas. Variability of light attenuation coefficient spectra is shown. Measurement of concentration and of sizes of above mantioned algas was also performed.