Wyniki wyszukiwania - Biblioteka Nauki

1

Uproszczone modele długookresowej morfodynamiki stożka ujściowego Wisły

100%

Cerkowniak G. R.

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tom nr 4

155--164

PL

Uproszczony, dwuwariantowy model kształtu stożka ujściowego Wisły oparty na założeniu półkolistego (pierwszy wariant) oraz trójkątnego (drugi wariant) obrysu plateau. Weryfikacja modelu na podstawie map i danych archiwalnych. Długość wschodniego falochronu kierującego a zasięg plateau stożka.

EN

Simplified two-variant model of a geometry of the Vistula alluvial fan assuming semicircular (first variant) and triangular (second variant) contour of the plateau. Model verification based on maps and archival data. Length of the eastern outlet jetty vs. range of the fan plateau.

2

Transport of Fine Sediments in MarineWaterbodies Near River Mouths: Preliminary Results

63%

Cerkowniak G. R. , Kowalewski M.

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tom Vol. 65, nr 4

255--275

EN

Transport of fine sediments depends mainly on the efficiency of flocculation. Flocculation, understood as the result of simultaneous processes of aggregation of particles and floc break-up, is a common phenomenon in marine environments. It is typical of fine sediments. This study presents a mathematical model of fine sediment transport. A model of flocculation is an important part of this model. Its main assumption is that flocculation is governed by turbulence. The model was qualitatively tested in a simplified theoretical waterbody. Such factors as the wind direction, wind speed, river discharge and concentration of suspension in the river were investigated. The results show that the proposed model describes reasonably well the lithodynamic processes characteristic of fine flocculating sediments. Thus it seems possible to apply it for description of fine sediment transport under real wave–current conditions that occur in many marine waterbodies near river mouths.

3

Wave-Induced Sediment Motion Beyond the Surf Zone: Case Study of Lubiatowo (Poland)

51%

Cerkowniak G. R. , Ostrowski R. , Stella M.

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tom Vol. 62, nr 1-2

27--39

EN

The paper presents results of field and theoretical investigations of a natural sandy shore located near the IBW PAN Coastal Research Station in Lubiatowo (Poland, the south Baltic Sea). The study site displays multi-bar cross-shore profiles that intensively dissipate wave energy, mostly by breaking. The main field data comprise offshore wave parameters and three cross-shore bathymetric profiles. Waveinduced nearbed velocities and bed shear stresses are theoretically modelled for weak, moderate, strong and extreme storm conditions to determine sediment motion regimes at various locations on the seaward boundary of the surf zone. The paper contains a discussion on the depth of closure concept, according to which the offshore range of sea bottom changes can be determined by the extreme seasonal deep-water wave parameters.

4

Depth of closure in the multi-bar non-tidal nearshore zone of the Baltic Sea: Lubiatowo (Poland) case study

51%

Cerkowniak G. R. , Ostrowski R. , Stella M.

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tom Vol. 30, No. 1

180--188

EN

The paper deals with the natural sandy nearshore zone, located close to Lubiatowo in Poland (the south Baltic Sea). The study site is characterised by multi-bar sea bottom profile, intensively dissipating wave energy. The paper presents a verification of the depth of closure concept. The analysis and theoretical considerations are based on field data collected at the IBW PAN Coastal Research Station in Lubiatowo. The data comprises cross-shore bathymetric profiles and the deep-water wave buoy records. The depth of closure determined from bathymetric surveys was found to be bigger than the one calculated using parameters of the effective significant wave height.

PL

Artykuł dotyczy naturalnej piaszczystej strefy przybrzeżnej znajdującej się w pobliżu Lubiatowa w Polsce (południowy Bałtyk). Miejsce badań charakteryzuje się wielorewowym Profilem dna morskiego, powodującymi intensywną dyssypację energii fal. Praca przedstawia weryfikację koncepcji głębokości zamknięcia. Analiza i rozważania teoretyczne opierają się na danych terenowych zebranych w Morskim Laboratorium Brzegowym IBW PAN w Lubiatowie. Dane te zawierają profile batymetryczne poprzeczne do brzegu oraz rejestracje z głębokowodnej boi falowej. Głębokość zamknięcia wyznaczona z pomiarów batymetrycznych okazuje się większa niż obliczona z parametrów efektywnej fali znacznej.

5

Application of Dean's curve to investigation of a long-term evolution of the Southern Baltic multi-bar shore profile

51%

Cerkowniak G. R. , Ostrowski R. , Pruszak Z.

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nr 1

EN

The paper presents the results of studies on the long-term evolution of the multi-bar cross-shore profiles. The analysis is focused on time-dependent variability of shoreline position, a modified parameter A of the conventional Dean's equation and a parameter F describing the amount of nearshore sediment resources in the multi-bar cross-shore profile. The study also deals with interrelationships between these quantities. The analysis is carried out using field data collected at Lubiatowo, Poland, on the dissipative shore, representative for the south Baltic. The considered coastal segment is found to be stable in the long-term scale. The results of analysis show that the parameter A can either increase or decrease together with the shoreline advance. It is concluded that the shoreline position change is a parameter unsatisfactorily representative for behaviour of the seashore. The use of the Dean's approximation for estimation of the sediment resources F on the multi-bar seashore profiles is found reasonable to eliminate the effects of peculiarities of such shores.