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Wyświetlanie 1-13 z 13
Tytuł:
Meteorological influences on the surface hydrographic patterns of the North Aegean Sea
Autorzy:
Sylaios, G.
Powiązania:
https://bibliotekanauki.pl/articles/48232.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
water mass
Baltic Sea
Aegean Sea
sea water
hydrographic data
wind stress
bottom topography
meteorological influence
hydrographic pattern
Anthos Peninsula
salinity
Opis:
Hydrographic data from the North Aegean Sea were used to examine the summer variability of surface water masses during the period 1998–2001. Attention was placed on the surface hydrographic features of the area, such as the Black Sea Water (BSW) plume expansion, the frontal characteristics of the BSW with the Levantine Intermediate Water (LIW) and the variability of submesoscale hydrographic features (such as the Samothraki Anticyclone). Strong southerly wind stresses were found responsible for relaxing the horizontal density gradients across the BSW-LIW frontal zone and displacing this front to the north of Lemnos Island, thus suppressing the Samothraki Anticyclone towards the Thracian Sea continental shelf. Under northerly winds, the BSW-LIWfront returns to its regular position (south of Lemnos Island), thus allowing the horizontal expansion of the Samothraki gyre up to the Athos Peninsula. Present results indicate the importance of medium-term wind stress effects on the generation of Samothraki Anticyclone suppression/expansion events.
Źródło:
Oceanologia; 2011, 53, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Increases in the temperature and salinity of deep and intermediate waters in the West Spitsbergen Current region in 1997–2016
Autorzy:
Merchel, M.
Walczowski, W.
Powiązania:
https://bibliotekanauki.pl/articles/2079090.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
climate change
deep water
temperature
salinity
intermediate water
West Spitsbergen current
hydrographic data
Opis:
This study investigated the temporal variability in the basic physical properties of deep and intermediate waters in the West Spitsbergen Current region at 76°30’N latitude from 1997 to 2016. Emphasis was placed on quantifying the changes in temperature and salinity and determining the potential drivers of these changes. Hydrographic data were obtained during annual summer cruises aboard the r/v Oceania in the Nordic Seas. The increase in the water temperature, which was especially strong in the western part of the investigated section, was associated with considerable changes in the water layers salinity. The temperature and salinity of the intermediate water increased much faster (0.021°C yr−1 and 0.0022 yr−1, respectively) than those of the deep water (0.009°C yr−1 and 0.0004 yr−1, respectively). The warming rate in the upper 2000 m was also higher than the mean warming rate of the global ocean. The source of the deep water temperature and salinity increases was the deep water inflow from the Arctic Ocean into the Greenland Sea. In contrast, the increase in these properties in the intermediate water was associated with the advection of warmer and more saline Atlantic Water from the North Atlantic to the Nordic Seas.
Źródło:
Oceanologia; 2020, 62, 4PA; 501-510
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Processes and factors influencing the through-flow of new deepwater in the Bornholm Basin
Autorzy:
Stigebrandt, A.
Powiązania:
https://bibliotekanauki.pl/articles/49102.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
hydrographic condition
Bornholm Basin
salinity
oxygen concentration
vertical stratification
deep water
Baltic Sea
Opis:
This paper is based on the idea that the hydrographical conditions in the Bornholm Basin, and any other basin, can be understood from knowledge of general hydromechanical principles and basin-specific factors. Published results on the variability of the vertical stratification are shown and discussed. Such analyses demonstrate the residence time of water at different depth levels. Different modes of currents forced by winds and by stratification gradients at open vertical boundaries are presented. Vertical mixing is discussed and published results for the Bornholm Basin are shown. An experiment demonstrates that the diffusive properties of the enclosed basin, i.e. below the sill depth of the Słupsk Furrow, can be computed quite well from the horizontal mean vertical diffusivity obtained from historical hydrographical observations. A published two decades long simulation of the vertical stratification shows that the through flow and modification of new deepwater in the Bornholm Basin can be well described based on existing knowledge regarding crucial hydromechanical processes. It also suggests, indirectly, that there should be a weak anticyclonic circulation above the sill depth, which is supported by current measurements.
Źródło:
Oceanologia; 2017, 59, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Unravelling the spatio-temporal variation of zooplankton community from the river Matla in the Sundarbans Estuarine System, India
Autorzy:
Nandy, T.
Mandal, S.
Powiązania:
https://bibliotekanauki.pl/articles/2079187.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
zooplankton
Copepoda
bioindicator
spatio-temporal variability
ecosystem functioning
seasonal fluctuation
estuarine water
Indian Sundarban
hydrographic change
Opis:
Zooplankton is an important bioindicator of ecosystem functioning. Knowledge of the seasonal fluctuation in the zooplankton population in estuarine waters of the Indian Sundarbans is rather limited. In the present study, we analysed the community structure of zooplankton assemblages and their spatio-temporal variations based on different multivariate statistics and indicator value analysis. A total of 56 taxa were identified and the density was primarily dominated by planktonic copepods and few meroplankton communities during four sampling seasons. The most abundant species were: Acartia spinicauda, Acartia sp., Bestiolina similis, Euterpina acutifrons, Labidocera acuta, Paracalanus aculeatus, Paracalanus parvus and Paracalanus indicus. Canonical Correspondence Analysis highlighted that temperature, pH, DO, salinity and nutrients were the prevailing environmental parameters associated with significant spatio-temporal changes of zooplankton distribution in this area. The highest abundance of zooplankton was recorded in winter, followed by monsoon, summer and spring. Throughout the study period, different zooplankton indices were observed in good condition. Seasonal occurrence of dominant zooplankton with high IndVal index was markedly observed and it might be used as a potential bioindicator for a particular season and environmental condition in this estuarine complex. The results of this study provide evidence for the presence of warm water species in the estuarine waters of the Indian Sundarbans and can be a clear indication of climate change-mediated elevated temperature in the estuarine system. Our results underscore the high diversity of zooplankton from mangrove dominated estuarine complex and emphasize the need for long-term monitoring in ecologically fragile ecosystems like the Sundarbans Estuarine System.
Źródło:
Oceanologia; 2020, 62, 3; 326-346
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling the ecosystem response to summer coastal upwelling in the Northern South China Sea
Autorzy:
Jiang, R.
Wang, Y.-S.
Powiązania:
https://bibliotekanauki.pl/articles/47804.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
nutrient
phytoplankton
zooplankton
ecosystem model
coastal upwelling
hydrographic condition
seasonal change
sea surface temperature
South China Sea
Opis:
A coupled three-dimensional physical model and a nitrogen-based nutrient, phytoplankton, zooplankton, and detritus (NPZD) ecosystem model were applied to simulate the summer coastal upwelling system over the continental shelf of northern South China Sea (NSCS) and its impact on hydrographic conditions and ecosystem. The simulated results were comprehensively validated against field and satellite measurements. The model results show that the near shore ecosystem of NSCS has significant responses to the summer coastal upwelling system. The Shantou Coast to the Nanri Islands of Fujian province (YD) and the east of the Leizhou Peninsula (QD) are two main regions affected by NSCS summer coast upwelling. During summer, these two coastal areas are characterized by nearshore cold and high salinity upwelling current. Further, the summer coastal upwelling serves as a perfect nutrient pump, which lifts up and advects nutrient-rich current from deep to surface, from inner shelf to about 30 km outer shelf. This nutrient source reaches its maximum in the middle of July and then begins to decrease. However, the maximum phytoplankton and chlorophyll a do not coincide with the maximum nutrients and delay for about 10 days. Because of the intensive seasonal thermocline and the complicated current transporting through Qiongzhou strait, the ecological responding of QD is less pronounced than YD. This study has a better understanding of the physically modulated ecological responses to the NSCS summer coastal upwelling system.
Źródło:
Oceanologia; 2018, 60, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Annual cycle of phytoplankton community through the water column: Study applied to the implementation of bivalve offshore aquaculture in the Southeastern Bay of Biscay
Autorzy:
Muniz, O.
Revilla, M.
Rodriguez, J.G.
Laza-Martinez, A.
Fontan, A.
Powiązania:
https://bibliotekanauki.pl/articles/47941.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
phytoplankton community
water column
open water
bivalve
biomass
chlorophyll a
nutrient
hydrographic condition
environmental variability
Biscay Bay
Źródło:
Oceanologia; 2019, 61, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pronounced anomalies of air, water, ice conditions in the Barents and Kara Seas, and the Sea of Azov
Autorzy:
Matishov, G.G.
Dzhenyuk, S.L.
Moiseev, D.V.
Zhichkin, A.P.
Powiązania:
https://bibliotekanauki.pl/articles/49104.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
climate
water temperature
anomaly
air temperature
sea ice
Barents Sea
Kara Sea
Azov Sea
hydrographic condition
winter condition
Źródło:
Oceanologia; 2014, 56, 3
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An overview of the teta - S correlations in Fram Strait based on the MIZEX 84 data
Autorzy:
Schlichtholz, P.
Houssais, M.N.
Powiązania:
https://bibliotekanauki.pl/articles/47520.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
temperature
Fram Strait
Atlantic water
hydrographic cast
MIZEX 84 experiment
teta-S diagram
water mass
salinity
Arctic Ocean
Opis:
The water masses in Fram Strait have been analyzed on the basis of hydrographic casts taken in summer 1984 during the MIZEX 84 experiment. In particular, θ − S diagrams for 16 areas, each 5◦ in longitude and 1◦ in latitude, covering the strait from 77◦N to 81◦ N are used to characterize the water masses and discuss their possible origin. Near the surface, the East Greenland Polar Front clearly separates the lighter, cold and fresh Polar Water (PW) from the heavier, warm and saline Atlantic Water (AW). In the upper ocean, the data show a large spreading of the temperature maximum in the θ − S space associated with different modes of the AW recirculating southward below the PW. Two geographically distinct salinity minima are found in the intermediate layer below the AW. The denser one, in the Boreas Basin, is a feature typical of the Arctic Intermediate Water (AIW) formed by winter convection to the south of the strait, while the lighter one is sandwiched in the Arctic Ocean outflow between the AW layer and the Upper Polar Deep Water (UPDW) characterized by a downward salinity increase. In the deep layer, two salinity maxima are present. The shallower (and warmer) one, associated with the Canadian Basin Deep Water (CBDW), appears all along the East Greenland Slope. A similar but weaker maximum is also found in the southeastern part of the strait. This maximum is perhaps a remnant of the maximum in the East Greenland Current after it has been recirculated back to the strait around the cyclonic gyres of the Nordic Seas. The deeper one appears typically as a near-bottom salinity jump characteristic of the Eurasian Basin Deep Water (EBDW). The jump is found in two distinct areas of the strait, to the north-west in the Lena Trough and to the south-east in the rift valley of the Knipovich Ridge. The maximum in the former area should have been advected from the Arctic Ocean below the CBDW, while the maximum in the latter area might have originated from haline convection on the adjacent shelves. Some EBDW is trapped in the Molloy Deep over a denser water with salinity decreasing down to the bottom and temperature in the range of the Greenland Sea Deep Water (GSDW).
Źródło:
Oceanologia; 2002, 44, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hydrographic and hydrochemical conditions in the Gotland Deep area between 1992 and 2003
Autorzy:
Nausch, G.
Matthaus, W.
Feistel, R.
Powiązania:
https://bibliotekanauki.pl/articles/48546.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
nutrient pool
temperature
hydrography
hydrochemical condition
ventilation
nutrient distribution
bottom water
salinity
Baltic Sea
stagnation period
hydrographic condition
Gotland Deep
Opis:
The paper describes the hydrographic-hydrochemical development in the eastern Gotland Basin between the major saltwater inflows into the Baltic Sea in 1993 and 2003. This period is characterised by only low inflow activity. The most important hydrographic events were the effects of the very strong inflow in 1993 and the weak inflows in 1993/1994 and 1997. The 1993/1994 inflows led to deep-water renewal, a steep fall in deep-water temperatures, and increasing salinity. The effects of the inflow of very warm, saline and oxygen-rich water in autumn 1997 were observed in the deep water in 1998, resulting in temperatures rising to 7◦C. The recent renewal in spring 2003 is reflected in the decreasing temperature, higher salinity and improved ventilation of the bottom water. Changes in the redox conditions exert a considerable influence on the nutrient distribution. During stagnation periods, there is enrichment of phosphate and ammonium, while nitrate is absent. Thus, around 31 μmol l−1 ammonium and 7 μmol l−1 phosphate were measured prior to the water renewal in 2003. Deepwater ventilation results in lower phosphate concentrations of around 2 μmol l−1, the nitrification of ammonium and the occurrence of nitrate. For the observation period, an estimate of nutrients stored in the deep water was done for the eastern Gotland Basin. During the recent stagnation period, there was an increase of up to 150% in the phosphate pool below the halocline, whereas the pool of inorganic nitrogen compounds decreased to 80% compared with 1992 when the previous stagnation period had ended. Under specific circumstances, these unbalanced nutrients can be made available to the upper water layers and can induce large-scale blooms of algae, especially of cyanobacteria.
Źródło:
Oceanologia; 2003, 45, 4
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quality assessment of atmospheric surface fields over the Baltic Sea from an ensemble of regional climate model simulations with respect to ocean dynamics
Autorzy:
Meier, H.E.M.
Hoglund, A.
Doscher, R.
Andersson, H.
Loptien, U.
Kjellstrom, E.
Powiązania:
https://bibliotekanauki.pl/articles/48250.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
atmosphere-ocean coupling
Baltic region
climate change
climate model
ecosystem
global warming
hydrographic change
regional climate
regional climate modelling
sea ice
temperature
water temperature
Opis:
Climate model results for the Baltic Sea region from an ensemble of eight simulations using the Rossby Centre Atmosphere model version 3 (RCA3) driven with lateral boundary data from global climate models (GCMs) are compared with results from a downscaled ERA40 simulation and gridded observations from 1980 –2006. The results showed that data from RCA3 scenario simulations should not be used as forcing for Baltic Sea models in climate change impact studies because biases of the control climate significantly affect the simulated changes of future projections. For instance, biases of the sea ice cover in RCA3 in the present climate affect the sensitivity of the model’s response to changing climate due to the ice-albedo feedback. From the large ensemble of available RCA3 scenario simulations two GCMs with good performance in downscaling experiments during the control period 1980–2006 were selected. In this study, only the quality of atmospheric surface fields over the Baltic Sea was chosen as a selection criterion. For the greenhouse gas emission scenario A1B two transient simulations for 1961 –2100 driven by these two GCMs were performed using the regional, fully coupled atmosphere-ice-ocean model RCAO. It was shown that RCAO has the potential to improve the results in downscaling experiments driven by GCMs considerably, because sea surface temperatures and sea ice concentrations are calculated more realistically with RCAO than when RCA3 has been forced with surface boundary data from GCMs. For instance, the seasonal 2 m air temperature cycle is closer to observations in RCAO than in RCA3 downscaling simulations. However, the parameterizations of air-sea fluxes in RCAO need to be improved.
Źródło:
Oceanologia; 2011, 53, (1-TI)
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Geostrophic current patterns off the Egyptian Mediterranean coast
Autorzy:
Kamel, M.S.
Powiązania:
https://bibliotekanauki.pl/articles/48462.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
geostrophic current circulation
hydrographic data
Egyptian Mediterranean coast
Salum Bay
Egypt
Nile Delta
Port Said
nearshore area
water mass
surface water
salinity
oxygen content
Opis:
Using objectively analysed hydrographic data, currents have been calculated off the Egyptian Mediterranean coast at the surface and at 30, 50, 75, 100, 200 and 300 m depths for the four seasons. The surface circulation is dominated by an anticyclonic circulation off Salum Bay in winter, spring and summer. In nearshore areas, the current flows eastwards at the shallower levels but westwards at the deeper levels. Off the Nile Delta, the current is almost eastward with a higher velocity in summer and autumn, while in spring it is very weak. Off the area between Port Said and Rafah, there is a clear cyclonic circulation appearing in all seasons except winter. At 50 and 75 m depth, the velocity of the circulation is weak. At 100 m depth, the circulation that appeared between Matruh and Alamen in summer decreases in area and magnitude at the former depths. At 200 and 300 m in winter, the current velocity is quite low. In spring the current flows southwards off the area between Rafah and Port Said. In summer, the current off the area between Port Said and Rafah is quite strong and flows to the south. The situation in autumn is quite similar to that in summer, except in the eastern area, where the current is a westward one.
Źródło:
Oceanologia; 2010, 52, 2; 299-310
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phytoplankton and environmental variables as a water quality indicator for the beaches at Matrouh, South-Eastern Mediterranean Sea, Egypt: an assessment
Autorzy:
Gharib, S.M.
El-Sherif, Z.M.
Abdel-Halim, A.M.
Radwan, A.A.
Powiązania:
https://bibliotekanauki.pl/articles/48802.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
abiotic environment
beach
biotic environment
community structure
diversity index
Egypt
environment variability
hydrochemical change
hydrographic change
marine environment
Matrouh beach
Mediterranean Sea
nutrient concentration
phytoplankton
water quality
Opis:
This study was carried out to determine the water quality of the beaches at Matrouh, south-eastern Mediterranean Sea, Egypt, by studying environmental variables as well as phytoplankton abundance and community structure. Surface water samples were monitored from a series of beach sites over a period of five seasons during 2009–2010. A total of 203 phytoplankton species were identified from seven algal divisions. Seasonal differences in the quantitative and qualitative composition of the phytoplankton communities in the different sites were marked. Nutrient concentrations and phytoplankton abundances were found to be poorer than those of many other areas along Egyptian coast. The Shannon-Wiener Diversity Index classified Matrouh water as being between clean and moderately polluted, whereas the WQI demonstrated that it was between good and excellent. It can be concluded that the index based onWQI is currently more suitable than the phytoplankton species index for assessing the quality of the water of the Matrouh beaches.
Źródło:
Oceanologia; 2011, 53, 3
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-13 z 13

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