Wszystkie pola: Ocean colour - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: SeaWiFS-derived products in the Baltic Sea: performance analysis of a simple atmospheric correction algorithm
Autorzy:: Bulgarelli, B.
Melin, F.
Zibordi, G.
Powiązania:: https://bibliotekanauki.pl/articles/47664.pdf
Data publikacji:: 2003
Wydawca:: Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:: ocean colour
remote sensing
accuracy analysis
Baltic Sea
atmospheric correction
Opis:: The accuracyan alysis of an approximate atmospheric correction algorithm for the processing of SeaWiFS data has been investigated for the Baltic Sea. The analysis made use of theoretical radiances produced with the FEM radiative transfer code for representative atmosphere-water test cases. The studysho wed uncertainties in the determination of the aerosol optical thickness at 865 nm and of the ˚Angstr¨om exponent lower than ±5% and ±10%, respectively. These results were confirmed bythe analysis of 59 match-ups between satellite-derived and in situ measurements for a site located in the central Baltic. Because of the relativelyhig h yellow substance absorption, often combined with the slanted solar illumination, the retrieval of the water-leaving radiance in the blue part of the spectrum appeared to be highlyd egraded, to the extent that almost no correlation was found between retrieved and simulated values. Better results were obtained at the other wavelengths. The accuracyin the estimation of the remote sensing reflectance ratio R35 decreased with diminishing chlorophyll a concentration and increasing yellow substance absorption, ranging between ±7% and ±47%. The propagation of R35 uncertainties on chlorophyll a estimation was quantified. Keeping the same atmosphere-water conditions, the atmospheric correction scheme appeared sensitive to seasonal changes in the Sun zenith.
Źródło:: Oceanologia; 2003, 45, 4
0078-3234
Pojawia się w:: Oceanologia
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Spectral effects in bio-optical control on the ocean system
Autorzy:: Sathyendranath, S.
Platt, T.
Powiązania:: https://bibliotekanauki.pl/articles/47462.pdf
Data publikacji:: 2007
Wydawca:: Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:: primary production
ocean colour
bio-optical property
remote sensing
ocean ecosystem
phytoplankton
Opis:: The influence of phytoplankton on the spectral structure of the submarine irradiance field is reviewed. The implications for the ocean system of the spectral response by phytoplankton to the ambient light field are discussed. For example, it provides the basis for retrieval of phytoplankton biomass by visible spectral radiometry (ocean-colour remote sensing). In the computation of primary production, the results of spectral models differ in a known and systematic manner from those of non-spectral ones. The bias can be corrected without risk of incurring additional random errors. The models in use for phytoplankton growth, whether based on available light or absorbed light, whether expressed in terms of chlorophyll or carbon, are shown all to conform to the same basic formalism with the same parameters. Residual uncertainty lies less with the models than with the parameters required for their implementation. The submarine light field and the spectral characteristics of phytoplankton carry latent information on phytoplankton community structure. Differences in spectral response by different functional types of phytoplankton are small but significant. Optical considerations limit the maximum phytoplankton biomass that can be sustained in a given surface mixed layer. Moreover, the upper bound on the biomass depends on the spectral response of the dominant phytoplankton taxa. As a result, an optical control exists in the mixed layer that tends to resist extreme excursions of the biomass and also to maintain biodiversity in the phytoplankton.
Źródło:: Oceanologia; 2007, 49, 1
0078-3234
Pojawia się w:: Oceanologia
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Comparison of in situ and satellite ocean color determinations of particulate organic carbon concentration in the global ocean
Autorzy:: Swirgon, M.
Stramska, M.
Powiązania:: https://bibliotekanauki.pl/articles/48631.pdf
Data publikacji:: 2015
Wydawca:: Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:: ocean colour
particulate organic carbon
dissolved organic carbon
ocean ecosystem
chlorophyll concentration
phytoplankton biomass
Źródło:: Oceanologia; 2015, 57, 1
0078-3234
Pojawia się w:: Oceanologia
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Spatio-temporal variability in the Brazil-Malvinas Confluence Zone (BMCZ), based on spectroradiometric MODIS-AQUA chlorophyll-a observations
Autorzy:: Telesca, L.
Pierini, J.O.
Lovallo, M.
Santamaria-del-Angel, E.
Powiązania:: https://bibliotekanauki.pl/articles/48518.pdf
Data publikacji:: 2018
Wydawca:: Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:: confluence zone
environmental variation
sea water
phytoplankton
spatio-temporal variability
chlorophyll a
ocean colour
remote sensing
Opis:: The Brazil–Malvinas Confluence Zone (BMCZ) is characterized by high environmental variation, which could be reflected in several optical types of water, from one containing only phytoplankton and sea water to other optically more complex. In this paper, we analyze the spatio-temporal variability of the Chlorophyll-a detected by the ocean color sensor (CHLAsat) in BMCZ in order to understand its environmental variability. We use the MODIS-Aqua CHLAsat monthly composites imagery from 2002 to 2015, and applied two statistical methods: the correlogram-based robust periodogram to identify, over a broad spectrum of temporal, the most significant periodicities, and the pixel gradient distribution to study the spatial-temporal gradients within the BMCZ and variations over the continental shelf and coastal waters. Our results point out to the predominance of the annual cycle over most of the investigated area, although an area from latitude 37°S in direction NE, alongshore of Uruguay to Brazil, evidences interannual periodicities, possibly related to variations in the discharge of the Rio de la Plata associated with the El Niño phenomena. The ocean color spectroradiometric signature in terms of pixel gradient presents a relatively high variability (∼0.0 to 0.65 mg m−3); in particular the high values of the pixel gradient correspond to saline front of the estuarine system of Rio de la Plata, and to the strip of the platform that extends along the isobaths of 80 m (coast of Uruguay), especially in the center and south of the study area.
Źródło:: Oceanologia; 2018, 60, 1
0078-3234
Pojawia się w:: Oceanologia
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Two models for absorption by coloured dissolved organic matter (CDOM)
Autorzy:: Schwarz, J.N.
Kowalczuk, P.
Kaczmarek, S.
Cota, G.F.
Mitchell, B.G.
Kahru, M.
Chavez, F.P.
Cunningham, A.
McKee, D.
Gege, P.
Kishino, M.
Phinney, D.A.
Raine, R.
Powiązania:: https://bibliotekanauki.pl/articles/47774.pdf
Data publikacji:: 2002
Wydawca:: Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:: ocean colour
coloured dissolved organic matter
surface water
coastal water
spectrophotometric measurement
ultraviolet absorption
absorption
Vistula River
Opis:: The standard exponential model for CDOM absorption has been applied to data from diverse waters. Absorption at 440 nm (ag440) ranged between close to zero and 10 m−1, and the slope oft he semilogarithmic absorption spectrum over a minimum range of400 to 440 nm (s440) ranged between <0.01 and 0.04 nm−1. No relationship was found between ag440 or s440 and salinity. Except in the southern Baltic, s440 was found to have a broad distribution (0.0165 ± 0.0035), suggesting that it should be introduced as an additional variable in bio-optical models when ag440 is large. An alternative model for CDOM absorption was applied to available high quality UV-visible absorption spectra from the WisGla river (Poland). This model assumes that the CDOM absorption spectrum comprises distinct Gaussian absorption bands in the UV, similar to those ofb enzene. Five bands were fit to the data. The mean central energy ofal l bands was higher in early summer (E ∼7.2, 6.6, 6.4, 6.2 and 5.5 eV or 172, 188, 194, 200 and 226 nm) than in winter. The higher energy bands were found to decay in both height and width with increasing salinity, while lower energy bands broadened with increasing salinity. s440 was found to be correlated with shape parameters of the bands centred at 6.4 and 5.5 eV. While the exponential model is convenient for optical modelling and remote sensing applications, these results suggest that the Gaussian model offers a deeper understanding ofc hemical interactions affecting CDOM molecular structure.
Źródło:: Oceanologia; 2002, 44, 2
0078-3234
Pojawia się w:: Oceanologia
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Validation of SeaWiFS and MODIS Aqua-Terra aerosol products in coastal regions of European marginal seas
Autorzy:: Melin, F.
Zibordi, G.
Carlund, T.
Holben, B.N.
Stefan, S.
Powiązania:: https://bibliotekanauki.pl/articles/49171.pdf
Data publikacji:: 2013
Wydawca:: Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:: validation
aerosol
ocean colour
European marginal sea
aerosol optical thickness
coastal area
remote sensing
optical property
aerosol robotic network
Źródło:: Oceanologia; 2013, 55, 1
0078-3234
Pojawia się w:: Oceanologia
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Diffusive component of the vertical flux of particulate organic carbon in the North polar Atlantic
Autorzy:: Stramska, M.
Powiązania:: https://bibliotekanauki.pl/articles/48240.pdf
Data publikacji:: 2006
Wydawca:: Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:: organic matter
ocean colour
nutrient
inorganic carbon
remote sensing
particulate organic carbon
Atlantic Ocean
vertical flux
phytoplankton
solar energy
photosynthesis
Opis:: The diffusive component of the vertical flux of particulate organic carbon (POC) from the surface ocean layer has been estimated using a combination of the mixed layer model and ocean color data from the SeaWiFS satellite. The calculations were carried out for an example location in the north polar Atlantic centered at 75◦N and 0◦ E for the time period of 1998–2004. The satellite estimates of surface POC derived using a regional ocean color algorithm were applied as an input to the model driven by local surface heat and momentum fluxes. For each year of the examined period, the diffusive POC flux was estimated at 200-m depth from April through December. The highest flux is generally observed in the late fall as a result of increased heat loss and convectional mixing of surface waters. A relatively high diffusive POC flux is also observed in early spring, when surface waters are weakly stratified. In addition, the model results demonstrate significant interannual variability. The highest diffusive POC flux occurred in 1999 (about 4500 mg m−2 over the 9-month period). In 1998 and 2002 the estimated flux was about two orders of magnitude lower. The interannual variability of the diffusive POC flux is associated with mixed layer dynamics and underscores the importance of atmospheric forcing for POC export from the surface layer to the ocean’s interior.
Źródło:: Oceanologia; 2006, 48, 4
0078-3234
Pojawia się w:: Oceanologia
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Algorithms for the remote sensing of the Baltic ecosystem (DESAMBEM). Part 2: Empirical validation
Autorzy:: Darecki, M.
Ficek, D.
Krezel, A.
Ostrowska, M.
Majchrowski, R.
Wozniak, S.B.
Bradtke, K.
Dera, J.
Wozniak, B.
Powiązania:: https://bibliotekanauki.pl/articles/47590.pdf
Data publikacji:: 2008
Wydawca:: Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:: light-photosynthesis model
algorithm
chlorophyll
ocean colour
temperature
marine ecosystem
monitoring
empirical validation
primary production
Baltic ecosystem
remote sensing
Opis:: This paper is the second of two articles on the methodology of the remote sensing of the Baltic ecosystem. In Part 1 the authors presented the set of DESAMBEM algorithms for determining the major parameters of this ecosystem on the basis of satellite data (see Woźniak et al. 2008 – this issue). That article discussed in detail the mathematical apparatus of the algorithms. Part 2 presents the effects of the practical application of the algorithms and their validation, the latter based on satellite maps of selected Baltic ecosystem parameters: the distributions of the sea surface temperature (SST), the Photosynthetically Available Radiation (PAR) at the sea surface, the surface concentrations of chlorophyll a and the total primary production of organic matter. Particular emphasis was laid on analysing the precision of estimates of these and other parameters of the Baltic ecosystem, determined by remote sensing methods. The errors in these estimates turned out to be relatively small; hence, the set of DESAMBEM algorithms should in the future be utilised as the foundation for the effective satellite monitoring of the state and functioning of the Baltic ecosystem.
Źródło:: Oceanologia; 2008, 50, 4; 509-538
0078-3234
Pojawia się w:: Oceanologia
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Validation of empirical and semi-analytical remote sensing algorithms for estimating absorption by Coloured Dissolved Organic Matter in the Baltic Sea from SeaWiFS and MODIS imagery
Autorzy:: Kowalczuk, P.
Darecki, M.
Zablocka, M.
Gorecka, I.
Powiązania:: https://bibliotekanauki.pl/articles/47876.pdf
Data publikacji:: 2010
Wydawca:: Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:: validation
remote sensing
Ocean colour
satellite validation
coloured dissolved organic matter
organic matter
absorption
Baltic Sea
Gdansk Gulf
Vistula River
Opis:: An extensive bio-optical data set obtained from field measurements was used to evaluate the performance of an empirical (Kowalczuk et al. 2005) and two semi- analytical algorithms: Carder et al. (1999) and GSM01 (Maritorena et al. 2002) for estimating CDOM absorption in the Baltic Sea. The data set includes coincident measurements of radiometric quantities and absorption coefficients of CDOM made during 43 cruises between 2000 and 2008. In the first stage of the analysis, the accuracy of the empirical algorithm by Kowalczuk et al. (2005) was assessed using in situ measurements of remote sensing reflectance. Validation results improved when matching points located in Gulf of Gdańsk close to the Vistula River mouth were eliminated from the data set. The calculated errors in the estimation of aCDOM(400) in the first phase of the analysis were Bias = −0.02, RMSE = 0.46 and R2 = 0.70. In the second stage, the empirical algorithm was tested on satellite data from SeaWiFS and MODIS imagery. The satellite data were corrected atmospherically with the MUMM algorithm designed for turbid coastal and inland waters and implemented in the SeaDAS software. The results of the best case scenario for estimating the CDOM absorption coefficient aCDOM(400), based on SeaWiFS data, were Bias = −0.02, RMSE = 0.23 and R2 = 0.40. The validation of the Kowalczuk et al. (2005) empirical algorithm applied to MODIS data led to a less accurate estimate of aCDOM(400): Bias = −0.03, RMSE = 0.19 and R2 = 0.29. This assessment of the accuracy of standard semi-analytical algorithms available in the SeaWiFS and MODIS imagery processing software revealed that both algorithms (GSM 01 and Carder) underestimate CDOM absorption in the Baltic Sea with mean systematic and random errors in excess of 70%. The paper presents examples of the application of the Kowalczuk et al. (2005) empirical algorithm for producing maps of the seasonal distribution of aCDOM(400) in the Baltic Sea between 2004 and 2008.
Źródło:: Oceanologia; 2010, 52, 2; 171-196
0078-3234
Pojawia się w:: Oceanologia
Dostawca treści:: Biblioteka Nauki