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Wyszukujesz frazę "Current" wg kryterium: Temat


Tytuł:
ADCP-referenced geostrophic velocity and transport in the West Spitsbergen current
Autorzy:
Osinski, R.
Wieczorek, P.
Beszczynska-Moller, A.
Goszczko, I.
Powiązania:
https://bibliotekanauki.pl/articles/48340.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Arctic circulation
Atlantic water
acoustic Doppler current profiler
geostrophic flow
West Spitsbergen current
Źródło:
Oceanologia; 2003, 45, 3
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coherent current oscillations and water exchange in the straits of the Gulf of Riga
Autorzy:
Talpsepp, L.
Powiązania:
https://bibliotekanauki.pl/articles/49149.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
current
water exchange
coherent current
Riga Gulf
Gulf of Riga Project
Baltic Sea
Opis:
The water exchange processes through the Irbe and Virtsu (Suur) Straits were investigated in 1993–1997 within the framework of a five-year study programme – the Gulf of Riga Project. Simultaneous current measurement data from autonomous mooring stations in both straits were available for the analysis in two periods. In addition to the dominant signals – inertial oscillations in the Virtsu Strait and diurnal oscillations in the Irbe Strait – low-frequency oscillations were found in both straits. During the experiment in July–August 1994, 12–14-day oscillations were observed in both straits: the maximum phase lag in the Virtsu Strait was 1 day. The other important low-frequency periodic component in both straits was 88 hours. In this case, the phase lag in the Virtsu Strait was about 20 hours. In the 1995 experiment in the Irbe Strait, 42-hour oscillations were observed with a phase lag of 10–12 hours. The amplitude was about 30 cm s−1 in both straits. As in Lilover et al. (1998), where the flow regime in the Irbe Strait was observed, we can interpret these oscillations as being wind-generated. The present work shows the existence of these disturbances also in the Virtsu Strait. The 88-hour oscillations observed in July–August 1994 can be interpreted as the first mode of the basin’s eigenoscillations according to the concept of Otsmann et al. (1997) of a basin with two separate outlets. The lowest frequency oscillation with the period of 12–14 days seemed to propagate to the Gulf of Riga from the Baltic Proper, but the generating force could not be established because there was no noticeable variability between depressions and anticyclones during that period. Based on the current measurements, two types of water exchange through the Irbe strait were established: the outflow over the whole cross-section of the strait, and a bidirectional flow with an inflow near the southern shore and increasing inflow in the near-bottom layers and an outflow in the northern part of the strait.
Źródło:
Oceanologia; 2005, 47, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Large halocline variations in the Northern Baltic Proper and associated meso- and basin-scale processes
Autorzy:
Elken, J.
Malkki, P.
Alenius, P.
Stipa, T.
Powiązania:
https://bibliotekanauki.pl/articles/47628.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Sopot
current
splitting area
Finland Gulf
saline water
conference
Baltic Sea
halocline
Opis:
The Northern Baltic Proper is a splitting area of the Baltic Sea saline water route towards the two terminal basins – the Gulf of Finland and the Western Gotland Basin. Large halocline variations (vertical isopycnal displacements of more than 20 m, intra-halocline current speeds above 20 cm s−1) appear during and following SW wind events, which rapidly increase the water storage in the Gulf of Finland and reverse the standard estuarine transport, causing an outflow in the lower layers. In the channel of variable topography, basin-scale barotropic flow pulses are converted into baroclinic mesoscale motions such as jet currents, sub-surface eddies and lowfrequency waves. The associated dynamics is analysed by the results from a special mesoscale experiment, routine observations and numerical modelling.
Źródło:
Oceanologia; 2006, 48, S
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Variability of currents over the southern slope of the Gulf of Finland
Autorzy:
Suhhova, I.
Pavelson, J.
Lagemaa, P.
Powiązania:
https://bibliotekanauki.pl/articles/48946.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
stratification
upwelling
downwelling
Finland Gulf
coastal sea water
seasonal thermocline
current velocity
Źródło:
Oceanologia; 2015, 57, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Long period oscillations in the longshore current on a sandy, barred coast investigated with singular spectrum analysis
Autorzy:
Kaczmarek, J.
Rozynski, G.
Pruszak, Z.
Powiązania:
https://bibliotekanauki.pl/articles/47837.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
beach process
nearshore region
longshore current
coastal process
infragravity wave
singular spectrum analysis
Opis:
The presence of infragravity waves in nearshore regions can be sought in the records of both water levels and wave-driven longshore currents. For this reason, time series of such currents in close proximity to the shoreline were analysed using Singular Spectrum Analysis (SSA). Simultaneously, the results obtained with this method were confronted with the output of Discrete Wavelet Transform (DWT), which had previously been applied to this data. The records of longshore currents were collected on a daily basis during field experiments in the autumns of 2002 and 2003 with sampling rates of 3 Hz and 0.5 Hz. This produced a large data set that allowed for the use of an advanced signal processing technique, capable of extracting patterns characteristic of low-, medium- and high-frequency bands. It provided similar evidence to that produced by DWT for the existence of infragravity waves along a dissipative coast with multiple bars. The study also demonstrated the utility of SSA for studies on coastal hydrodynamics. It also showed up the better user-friendliness of DWT in terms of pattern extraction and interpretation. On the other hand, SSA demonstrated a higher precision of pattern extraction once the DWT output was known, which is a manifestation of the synergy of the two methods when applied jointly.
Źródło:
Oceanologia; 2005, 47, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synoptic changes in the deep rim current during stagnant hydrographic conditions in the Eastern Gotland Basin, Baltic Sea
Autorzy:
Hagen, E.
Feistel, R.
Powiązania:
https://bibliotekanauki.pl/articles/49138.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Gotland Basin
hydrography
deep water condition
current measurement
Baltic Sea
Baltic Monitoring Programme
Opis:
Hydrographic and current measurements are analysed for stagnant deep-water conditions over the south-eastern topographic flank of the Eastern Gotland Basin (EGB) in April 2000. Results suggest a prevailing barotropic motion mode on a synoptic scale of several days. Deep along-slope volume transports derived from subsurface current meter moorings are compared with those of the baroclinic fraction of geostrophic motions crossing the plane of a hydrographic section. This was aligned perpendicular to deep isobaths and was repeated 40 times with a time step of six hours. Changes in regional winds produced a quasi-ten day cycle in the filling level of the Baltic Proper. Associated wave-like fluctuations of the mass field propagated cyclonically with a velocity of about 0.04 m s−1 around the deep basin’s rim. It is concluded that associated changes in deep volume transports result mainly from barotropically governed advection processes and that those of the baroclinic component of geostrophic currents provide a qualitatively and quantitatively quite inaccurate description of related transport fluctuations on a daily scale.
Źródło:
Oceanologia; 2007, 49, 2
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:
Modelling longshore sediment transport under asymmetric waves
Autorzy:
Ostrowski, R.
Szmytkiewicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/49027.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
coastal zone
hydrodynamic condition
sandy sediment
wave-current interaction
sediment transport
wave asymmetry
Opis:
Two wave theories are applied in calculations of longshore sediment transport rates: the second Stokes approximation and the cnoidal theory. These approaches are used to model sand motion in nearshore locations beyond and within the surf zone. Wave-current interaction in the nearbed layer and bed shear stresses are solved using a momentum integral method, whereas sediment transport is described by a three-layer model encompassing bedload, contact load and suspended load. Computational results for asymmetric waves are compared with the results obtained using linear wave theory and the conventional sediment transport models of Bailard (1981), Bijker (1971) and Van Rijn (1993).
Źródło:
Oceanologia; 2006, 48, 3
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The misalignment angle in vessel-mounted ADCP
Autorzy:
Osinski, R.
Powiązania:
https://bibliotekanauki.pl/articles/49054.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
cosinusoidal function
zooplankton
ship
acoustic Doppler current profiler
echo
acoustic pulse
depth
calibration
sediment
Opis:
A description of the misalignment angle and the consequences if it occurs is given. It is shown that because of gyrocompass errors, the misalignment angle error α has to be computed for each cruise. A simple method of calibrating the acoustic Doppler current profiler (ADCP) mounted on a vessel has been devised by fitting the cosinusoidal function. This is a post-processing method, suitable for calibrating previously collected data. Nevertheless, because of ADCP’s constructional peculiarities, the procedure must be repeated for each cruise.
Źródło:
Oceanologia; 2000, 42, 3
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Driving forces of sandy sediment transport beyond the surf zone
Autorzy:
Stella, M.
Ostrowski, R.
Szmytkiewicz, P.
Kapinski, J.
Marcinkowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/47878.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
sandy sediment
sediment transport
surf zone
wave-current interaction
roughness
coastal zone
Baltic Sea
Źródło:
Oceanologia; 2019, 61, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of landfast ice on the hydrography and circulation of the Baltic Sea coastal zone
Autorzy:
Merkouriadi, I.
Lepparanta, M.
Powiązania:
https://bibliotekanauki.pl/articles/49047.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Finland Gulf
hydrography
landfast ice
circulation
Baltic Sea
coastal zone
water temperature
salinity
current
Źródło:
Oceanologia; 2013, 55, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heat and salt fluxes in the West Spitsbergen Current area in summer
Autorzy:
Piechura, J.
Osinski, R.
Petelski, T.
Wozniak, S.B.
Powiązania:
https://bibliotekanauki.pl/articles/49050.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Spitsbergen Current
temperature
radiation flux
energy flux
heat flux
sea surface
salt flux
ocean circulation
Opis:
Fluxes of radiation, sensible and latent heat, and fluxes of heat and salt within the upper layer of the ocean were calculated on the basis of measurements carried out in the area of the Norwegian-Atlantic and West Spitsbergen Currents during summer 2000. The sea surface radiation balance was calculated from direct measurements of downward and upward short-wave (solar) radiation, the net radiation fluxes and sea surface temperature. The daily doses of radiation energy reaching and leaving the sea surface were also estimated. To calculate the vertical heat fluxes in the atmospheric boundary layer the bulk parameterisation method was used. In most cases, the calculated heat fluxes were rather low, the average sensible heat flux was c. 10 Wm−2, and the latent heat flux about one order of magnitude higher; this is what could be expected in summer. Salt fluxes to the air in the process of aerosol production are very small and can be neglected. In summer the highest quantities of heat and salt are exchanged during mixing with surrounding waters. According to our measurements, Atlantic Water on its northward course from about 70◦N to 79◦ N loses about 100 TWof heat and 900 × 103 kg of salt. We thought it could be interesting to find out what happens to them. Some preliminary results of our investigation are presented here.
Źródło:
Oceanologia; 2002, 44, 3
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kelvin-Helmholtz instabilities in the Colorado River Delta, Gulf of California
Autorzy:
Carbajal, N.
Vargas, J.T.
Rodriguez, J.H.G.
Montano Ley, Y.
Salas de Leon, D.A.
Powiązania:
https://bibliotekanauki.pl/articles/2078904.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Kelvin-Helmholtz instability
Colorado River Delta
tidal current
bottom sediment
bathymetry
suspended sediment
satellite image
Opis:
In the Colorado River Delta, the interaction of tidal currents and sea-bottom sediment formed, in geological times, large-scale seabed patterns known as sandbanks. These patterns are oriented along the delta, almost parallel to the dominant tidal flow, with the bathymetry having an undulating character across the delta. Calculations and analysis showed that the interaction of tidal currents with the bathymetry causes velocity shears, faster flowing over the ridges than in the troughs. Kelvin-Helmholtz instabilities emerge from the velocity shear, and a large amount of suspended sediment makes the instabilities visible in satellite images. The physical and dynamic conditions allowed us to find an explanation for the existence of these Kelvin-Helmholtz instabilities. Since sandbanks have been observed in different seas such as the North Sea, The Gulf of Korea, the Gulf of Khambhat in India, the Jiangsu coast in China, the Persian Gulf, and Moreton Bay in Australia, the results suggest the existence of instabilities in these areas. Satellite images, intense tidal currents, undulating topography, and suspended sediment made it possible to explain the generation and identification of KelvinHelmholtz instabilities.
Źródło:
Oceanologia; 2021, 63, 3; 321-328
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Formation and species composition of stormcast beach wrack in the Gulf of Riga, Baltic Sea
Autorzy:
Suursaar, U.
Torn, K.
Martin, G.
Herkul, K.
Kullas, T.
Powiązania:
https://bibliotekanauki.pl/articles/48538.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
beach wrack
species composition
wave
current
storm
hydrodynamic modelling
submerged vegetation
biodiversity
Riga Gulf
Baltic Sea
Źródło:
Oceanologia; 2014, 56, 4
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł

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