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Wyszukujesz frazę "Ocean" wg kryterium: Temat


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
Artykuł
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
Artykuł
Tytuł:
The integrated Arctic Ocean Observing System (iAOOS): an AOSB-CliC Observing Plan for the International Polar Year
Autorzy:
Dickson, B.
Powiązania:
https://bibliotekanauki.pl/articles/48790.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
climatic impact
International Polar Year
Arctic Ocean Observing System
Arctic Ocean
sea ice
climate change
Opis:
The debate on the climatic impact of Arctic change is currently focused on the fate of the perennial sea-ice and the climatic and social effects of its disappearance. Developments in our observing techniques mean that we are in prospect of being technically able to describe the ocean-atmosphere-cryosphere system of high northern latitudes operating as a complete system for the first time. Understanding this system and improving its predictability in models seems to be our most direct way of extending the ability of society to mitigate for or adapt to its changes, including global change. The integrated Arctic Ocean Observing System (iAOOS), described here, is a means of piecing together the available PIs, gear, ships and funding on the pan-Arctic scale that seems necessary to making the attempt, and the International Polar Year (2007–2009) provides the necessary stimulus for doing so.
Źródło:
Oceanologia; 2006, 48, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Warming of the West Spitsbergen current and sea ice North of Svalbard
Autorzy:
Piechura, J.
Walczowski, W.
Powiązania:
https://bibliotekanauki.pl/articles/48817.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
sea ice
ocean circulation
Nordic Sea
climate change
atmospheric circulation
West Spitsbergen
Arctic Ocean
warming
Opis:
According to the results of recent research, besides the atmospheric circulation, it is heat transport to the Arctic Ocean (AO) by ocean currents, the West Spitsbergen Current (WSC) in particular, that is playing a significant role in the process of Arctic warming. Data collected by the Institute of Oceanology, Polish Academy of Sciences (IO PAS), in the Norwegian and Greenland Seas, and Fram Strait during the last 20 years reveal considerable changes in the amount of heat transported by the WSC into the Arctic Ocean. An increase in Atlantic Water (AW) temperature and the intensification of heat transport were observed in 2004–06; after this period, both parameters decreased. The aim of this study was to find out whether the fluctuations in heat input by the WSC have influenced the sea-ice distribution around Svalbard. In fact they do, but oceanic heat transport should nonetheless be regarded as just one of many processes influencing sea-ice behaviour.
Źródło:
Oceanologia; 2009, 51, 2; 147-164
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Response of Eastern Indian Ocean (ODP Site 762B) benthic foraminiferal assemblages to the closure of the Indonesian seaway
Autorzy:
Rai, A.K.
Singh, V.B.
Powiązania:
https://bibliotekanauki.pl/articles/48495.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Indian Ocean
benthic foraminifera
productivity
upwelling
oligotrophic water
surface water
Pliocene
atmospheric circulation
ocean circulation
thermohaline circulation
Źródło:
Oceanologia; 2012, 54, 3
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Surface waves in deep and shallow waters
Autorzy:
Massel, S.R.
Powiązania:
https://bibliotekanauki.pl/articles/48826.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
surface wave
deep
shallow water
dynamic factor
marine environment
atmosphere-ocean interaction
ocean form
air-sea interface
hydrodynamics
Opis:
The motion of water due to surface waves is the most dynamic factor observed in the marine environment. In this review various aspects of the wave modelling of non-linear, steep surface waves and their role in the atmosphere-ocean interaction are discussed. Significant improvements in wave forecasting have been made in the last ten years. This is to a large extent related to substantial progress in the description of wind forcing and other processes, as well as to the more efficient use of satellite observations and assimilation methods. One striking observation is the increasing variety and complexity of models in which more physical processes are implemented, greater precision and resolution achieved and extended ranges of applicability demonstrated. However, in order to evaluate the applicability of particular models, comparison with high quality experimental data, collected in nature or under laboratory conditions, is necessary.
Źródło:
Oceanologia; 2010, 52, 1; 5-52
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A study on loops and eddies identified from the trajectories of drifters in the North Indian Ocean
Autorzy:
Dora, S.
Aparna, S.G.
Powiązania:
https://bibliotekanauki.pl/articles/2078762.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
trajectory
loop testing
eddy
geometric measurement
Indian Ocean
Opis:
We identify loops and eddies from the trajectories of the drifters in the North Indian Ocean (NIO) from October 1985 to March 2019. We use the geometric identification method to identify loops and eddies and compare them with the loops identified from loopers provided by Lumpkin (2016). In NIO, the number of loops estimated from loopers is less than the number of loops and eddies identified by the geometric identification method. A total of 761 loops are identified, of which 346 are eddies, whereas the loops identified from loopers are only 149. Larger radii loops and eddies are observed in the western and central Bay of Bengal (BoB) and the southwestern part of the Arabian Sea (AS). Temporal variation of loops and eddies shows a peak during April—May in the AS and September—October in the BoB. In the BoB, the temporal variation of cyclonic eddies matches with the variation in chlorophyll
Źródło:
Oceanologia; 2021, 63, 4; 516-530
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
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
Artykuł
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
Artykuł
Tytuł:
Indian Ocean wind speed variability and global teleconnection patterns
Autorzy:
Sinha, M.
Jha, S.
Chakraborty, P.
Powiązania:
https://bibliotekanauki.pl/articles/2079299.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
wind speed
variability
sea surface temperature
remote sensing
Indian Ocean
Opis:
The influence of the local sea surface temperature (SST) and remote ENSO (El Niño-Southern Oscillation) indices on the wind speed (WS) data were explored for the Indian Ocean region. Relationships among the parameters were studied using spatial correlation plots and significant correlation ranges. Two months (July and January) representing opposite monsoon phases were selected for analysis for the period 1950–2016. There was a significant negative correlation between WS and SST over the Bay of Bengal (BOB) during July. Although different ENSO indices correlated differently in different areas of the Indian Ocean, the region off the coast of Sri Lanka was most significantly teleconnected. The southwest monsoon locally impacted the WS and SST relationship and the WS parameter was remotely teleconnected in both the monsoon seasons. Further empirical orthogonal function (EOF) analysis was applied on the 67 years WS data of the BOB region to extract the dominant mode representing maximum variability of the total variance. The temporal pattern of the first principal component (PC1) of WS data was linked to the North Atlantic Oscillations in January and the Atlantic Multidecadal Oscillation in July respectively. The continuous wavelet power spectra of the PC1 of WS showed significant regions in the 2–4-year band resembling the ENSO variability. Wavelet coherence applied between PC1 of WS and the ENSO indices showed greatest values for January in the 8–16-year band and for July in the 0–4-year band. A close relationship was established between the WS variability in BOB and the ENSO indices.
Źródło:
Oceanologia; 2020, 62, 2; 126-138
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sky glint correction in measurements of upward radiance above the sea surface
Autorzy:
Olszewski, J.
Kowalczuk, P.
Powiązania:
https://bibliotekanauki.pl/articles/48314.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
marine optics
coastal water
remote sensing
glint reduction
ocean water
sea surface
Opis:
An experiment has been performed to determine the upward water-leaving radiance by non-contact measurement of the total upward and downward radiance above the sea surface from a moving ship. The method for achieving this aim is described: the radiance meters are both tilted in such a way that the upward radiance meter can ‘see’ that part of the measured downward radiance which would be reflected if the water surface were smooth and which is not derived directly from solar glitter. Both meters are firmly fixed in a special frame, which ensures that the required orientation is the most probable one. Time records of the measured parameters are analysed. The results are presented in several forms: frequency (histogram) analysis appears to be the most promising one.
Źródło:
Oceanologia; 2000, 42, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the geometry of ocean surface waves
Autorzy:
Massel, S.R.
Powiązania:
https://bibliotekanauki.pl/articles/48766.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
air-sea interaction
atmosphere-ocean interaction
deep water
dynamic factor
geometry
irregular wave
marine environment
ocean surface
regular wave
shallow water
surface wave
water motion
wave breaking
wave slope
Opis:
The factors influencing the atmosphere-ocean transfer of mass and momentum, as well as incipient wave breaking and the amount of energy dissipated due to breaking, are discussed in detail. In particular, the influence of directional spreading on the statistics of surface wave slopes and the area of the wind- roughened ocean surface is demonstrated. Theoretical analysis and comparison with the available experimental data show that unimodal directional spreading is not able to reproduce the observed ratio of the cross-wind/up-wind mean square slopes. Better agreement is achieved when bimodal directional spreading, consisting of two wrapped-Gaussian distributions, is applied. The bimodal form suggested by Ewans (1998) is used in the paper. Moreover, the formulae developed here show that the increase in the area due to surface waves is rather small for both regular and irregular waves.
Źródło:
Oceanologia; 2011, 53, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Variability of the specific fluorescence of chlorophyll in the ocean. Part 2. Fluorometric method of chlorophyll a determination
Autorzy:
Ostrowska, M.
Matorin, D.N.
Ficek, D.
Powiązania:
https://bibliotekanauki.pl/articles/47939.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
variability
luminescence
determination
chlorophyll a
fluorescence
sea
fluorometric method
phytoplankton
ocean
chlorophyll
Opis:
Two methods of determining the chlorophyll a concentration in the sea have been formulated on the basis of artificially induced fluorescence measured with the aid of submersible fluorometers. The method of statistical correlation is founded on the empirical relationship between fluorescence and chlorophyll concentration. The theoretical model of fluorescence described in Part 1 of this paper (see Ostrowska et al. 2000, this volume) provides the basis of the other method, the physical method. This describes the dependence of the specific fluorescence of phytoplankton on the chlorophyll concentration, a diversity of photophysiological properties of phytoplankton and the optical characteristics of the fluorometer. In order to assess their practicability, the methods were subjected to empirical verification. This showed that the physical method yielded chlorophyll concentrations of far greater accuracy. The respective error factors of the estimated chlorophyll concentration were x = 2.07 for the correlation method and x = 1.5 for the physical method. This means that the statistical logarithmic error varies from −52 to +107% in the case of the former method but only from −33 to +51% in the case of the latter. Thus, modifying the methodology has much improved the accuracy of chlorophyll determinations.
Źródło:
Oceanologia; 2000, 42, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of bio-optical parameters of open ocean waters
Autorzy:
Pelevin, V.N.
Rostovtseva, V.V.
Powiązania:
https://bibliotekanauki.pl/articles/48307.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
yellow substance
chlorophyll pigment
pigment
suspended matter
bio-optical modelling
ocean water
light absorption
Opis:
An original method for estimating the concentration of chlorophyll pigments, absorption of yellow substance and absorption of suspended matter without pigments and yellow substance in detritus using spectral diffuse attenuation coefficient for downwelling irradiance and irradiance reflectance data has been applied to sea waters of different types in the open ocean (case 1). Using the effective numerical single parameter classification with the water type optical index m as a parameter over the whole range of the open ocean waters, the calculations have been carried out and the light absorption spectra of sea waters tabulated. These spectra are used to optimize the absorption models and thus to estimate the concentrations of the main admixtures in sea water. The value of m can be determined from direct measurements of the downward irradiance attenuation coefficient at 500 nm or calculated from remote sensing data using the regressions given in the article. The sea water composition can then be readily estimated from the tables given for any open ocean area if that one parameter m characterizing the basin is known.
Źródło:
Oceanologia; 2001, 43, 4
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł

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