Wyniki wyszukiwania

1

Experimental study of short-period irradiance fluctuations under an undulated sea surface

100%

Dera J., Olszewski J.

Oceanologia

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1978

|

tom 10

2

The effect of daylight diffuseness on the focusing of sunlight by sea surface waves

100%

Stramski D.

Oceanologia

|

1986

|

tom 24

3

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Underwater light field and spectral distribution of attenuation depth in inland and coastal waters

84%

Kauer T., Arst H., Tuvikene L.

Oceanologia

|

2010

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tom 52

|

nr 2

155-170

The daily variations in the underwater irradiance spectra at different depths were determined using a combination of in situ data and model calculations. The spectra of the attenuation depth (relevant in optical remote sensing) were derived from these data. The results are presented for four Estonian lakes (Koorküla Valgjärv, Võrtsjärv, Harku, and Peipsi) and for coastal waters of the Baltic Sea (Pärnu Bay, Gulf of Riga).

4

Influence of underwater light fields on pigment characteristics in the Baltic Sea – results of statistical analysis

67%

Ston-Egiert J., Majchrowski R., Darecki M., Kosakowska A., Ostrowska M.

Oceanologia

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2012

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tom 54

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nr 1

5

Solar radiation in the Baltic Sea

67%

Dera J., Wozniak B.

Oceanologia

|

2010

|

tom 52

|

nr 4

The influx of solar radiation to the Baltic Sea and its penetration into its waters is described on the basis of selected results of optical and bio-optical studies in the Baltic published by various authors during the past ca 50 years. The variability in the natural irradiance of this sea is illustrated on time scales from short-term fluctuations occurring during a single day to differences in mean monthly values over a period of many years. Data on variability of the proportions between UV, VIS and IR energy in the light reaching the sea surface are also discussed. Long-term monthly mean values of the incident solar radiation flux at the surface of the Baltic Proper are given; they were obtained from meteorological and solar radiation measurements and model approximations. The transmittances of these mean monthly radiation fluxes across the surface of the Baltic are given, as are the typical energy and spectral characteristics of the underwater irradiance, its attenuation with depth in the sea and the associated euphotic zone depths, as well as typical ranges of variability of these characteristics in different Baltic basins. Some of these characteristics are illustrated by typical empirical data. These mean values are not fully representative, however, because with the sole use of classical in situ measurement methods from on board research vessels in the Baltic, it has not been possible to gather a sufficiently representative set of empirical data that would adequately reflect the variability of the optical haracteristics of all the basins of this sea. The article goes on to introduce the statistical model of vertical distributions of chlorophyll a concentration in the Baltic and the bio-otical model of Baltic Case 2 waters, the use of which contribute very significantly to this description of the optical characteristics and will enable this data set to be hugely expanded to include all the Baltic basins. This opportunity is presented by the optical parameterization of Baltic Case 2 waters, i.e. by the mathematical formulas of the model linking the coefficient of attenuation of downward irradiance with the surface chlorophyll a concentration, as well as the method developed for the efficient and systematic satellite remote sensing of the chlorophyll a concentration over the entire Baltic Sea area.

6

Influence of photo- and chromatic acclimation on pigment composition in the sea

67%

Majchrowski R., Ostrowska M.

Oceanologia

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2000

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tom 42

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nr 2

The aim of this work was to find statistical relationships between the concentrations of accessory pigments in natural populations of marine phytoplankton and the absolute levels and spectral distributions of underwater irradiance. To this end, empirical data sets from some 600 stations in different parts of the seas and oceans were analysed. These data were obtained from the authors’ own research and from the Internet’s bio-optical data base. They included the vertical distributions of the concentrations of various pigments (identified chromatographically) and the vertical and spectral distributions of the underwater irradiance measured in situ or determined indirectly from bio-optical models. The analysis covered a total of some 4000 points illustrating the dependence of pigment concentration on underwater irradiance characteristics, corresponding to different depths in the sea. The analysis showed that the factor governing the occurrence of photoprotecting carotenoids (PPC) is short-wave radiation λ < 480 nm. A mathematical relationship was established between the relative PPC concentration (relative with respect to the chlorophyll a concentration) and the magnitude of the absorbed radiative energy per unit mass of chlorophyll a from the spectral interval λ < 480 nm, averaged in the water layers Δz = 60 m (or less near the surface) to account for vertical mixing. This absorbed short-wave radiation (λ < 480 nm) was given the name of Potentially Destructive Radiation (PDR∗(z)). Analysis of the relationships between the concentrations of particular photosynthetic pigments (PSP), i.e. chlorophyll b, chlorophyll c, photosynthetic carotenoids (PSC), and the underwater irradiance characteristics indicated that these concentrations were only slightly dependent on the absolute level of irradiance E0(λ), but that they depended strongly on the relative spectral distribution of this irradiance f(λ) = E0(λ)/PAR0. The relevant approximate statistical relationships between the relative concentrations of particular PSP and the function of spectral fitting Fj , averaged in the layer Δz, were derived. Certain statistical relationships between the pigment composition of the phtyoplankton and the irradiance field characteristics are due to the photo- and chromatic acclimation of natural populations of marine phytoplankton. These relationships can be applied in models of the coefficients of light absorption by phytoplankton.

7

Modelling light and photosynthesis in the marine environment

67%

Wozniak B., Dera J., Ficek D., Majchrowski R., Ostrowska M., Kaczmarek S.

Oceanologia

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2003

|

tom 45

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nr 2

The overriding and far-reaching aim of our work has been to achieve a good understanding of the processes of light interaction with phytoplankton in the sea and to develop an innovative physical model of photosynthesis in the marine environment,suita ble for the remote sensing of marine primary production. Unlike previous models,the present one takes greater account of the complexity of the physiological processes in phytoplankton. We have focused in particular on photophysiological processes,whic h are governed directly or indirectly by light energy,or in which light, besides the nutrient content in and the temperature of seawater,is one of the principal limiting factors. To achieve this aim we have carried out comprehensive statistical analyses of the natural variability of the main photophysiological properties of phytoplankton and their links with the principal abiotic factors in the sea. These analyses have made use of extensive empirical data gathered in a wide diversity of seas and oceans by Polish and Russian teams as well as by joint Polish-Russian expeditions. Data sets available on the Internet have also been applied. As a result,a set of more or less complex,semi-empir ical models of light-stimulated processes occurring in marine phytoplankton cells has been developed. The trophic type of sea, photo-acclimation and the production of photoprotecting carotenoids,c hromatic acclimation and the production of various forms of chlorophyll-antennas and photosynthetic carotenoids,cell adaptation by the package effect, light absorption, photosynthesis, photoinhibition,the fluorescence effect,a nd the activation of PS2 centres are all considered in the models. These take into account not only the influence of light,but also, indirectly,tha t of the vertical mixing of water; in the case of photosynthesis,the quantum yield has been also formulated as being dependent on the nutrient concentrations and the temperature of seawater. The bio-optical spectral models of irradiance transmittance in case 1 oceanic waters and case 2 Baltic waters,dev eloped earlier,a lso are described in this paper. The development of the models presented here is not yet complete and they all need continual improvement. Nevertheless,w e have used them on a preliminary basis for calculating various photosynthetic characteristics at different depths in the sea,su ch as the concentration of chlorophyll and other pigments, and primary production. The practical algorithm we have constructed allows the vertical distribution of these characteristics to be determined from three input data: chlorophyll a concentration,irradiance, and temperature at the sea surface. Since all three data can be measured remotely,ou r algorithm can be applied as the ‘marine part’ of the remote sensing algorithms used for detecting marine photosynthesis.

Ograniczanie wyników

7 Oceanologia

3 Dera J.

3 Majchrowski R.

3 Ostrowska M.

2 Wozniak B.

1 Arst H.

1 Darecki M.

1 Ficek D.

1 Kaczmarek S.

1 Kauer T.

1 Kosakowska A.

1 Olszewski J.

1 Ston-Egiert J.

1 Stramski D.

1 Tuvikene L.

1 2012

2 2010

1 2003

1 2000

1 1986

1 1978

Experimental study of short-period irradiance fluctuations under an undulated sea surface

The effect of daylight diffuseness on the focusing of sunlight by sea surface waves

Underwater light field and spectral distribution of attenuation depth in inland and coastal waters

Influence of underwater light fields on pigment characteristics in the Baltic Sea – results of statistical analysis

Solar radiation in the Baltic Sea

Influence of photo- and chromatic acclimation on pigment composition in the sea

Modelling light and photosynthesis in the marine environment