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1

Contaminant transport in the surf zone

Chin David A.

Oceanologia

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2022

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No. 64 (4)

651--664

EN

Dispersion of dissolved contaminants introduced at various locations within and just outside the surf zone are investigated. It is shown that the Longuet-Higgins model of surf-zone hydrodynamics adequately describes the distribution of longshore currents measured at the laboratory scale. Relations are derived between the longitudinal and transverse dispersion coefficients and the influencing parameters. The maximum longitudinal dispersion coefficients are associated with tracer releases near the breaker line, and longitudinal dispersion coefficients generally increase with travel time for distances up to at least 10 surf-zone widths. In contrast, transverse dispersion coefficients remain relatively constant for increasing travel time. The longitudinal and transverse dispersion coefficients can be significantly influenced by assumed values of local turbulent diffusion and cross-shore shear dispersion.

2

Extended elliptic mild slope equation incorporating the nonlinear shoaling effect

Xiao Q. L., Li Ch. H., Fu X. Y., Wang M. J.

Polish Maritime Research

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2016

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S 1

44--51

EN

The transformation during wave propagation is significantly important for the calculations of hydraulic and coastal engineering, as well as the sediment transport. The exact wave height deformation calculation on the coasts is essential to near-shore hydrodynamics research and the structure design of coastal engineering. According to the wave shoaling results gained from the elliptical cosine wave theory, the nonlinear wave dispersion relation is adopted to develop the expression of the corresponding nonlinear wave shoaling coefficient. Based on the extended elliptic mild slope equation, an efficient wave numerical model is presented in this paper for predicting wave deformation across the complex topography and the surf zone, incorporating the nonlinear wave dispersion relation, the nonlinear wave shoaling coefficient and other energy dissipation factors. Especially, the phenomenon of wave recovery and second breaking could be shown by the present model. The classical Berkhoff single elliptic topography wave tests, the sinusoidal varying topography experiment, and complex composite slopes wave flume experiments are applied to verify the accuracy of the calculation of wave heights. Compared with experimental data, good agreements are found upon single elliptical topography and one-dimensional beach profiles, including uniform slope and step-type profiles. The results indicate that the newly-developed nonlinear wave shoaling coefficient improves the calculated accuracy of wave transformation in the surf zone efficiently, and the wave breaking is the key factor affecting the wave characteristics and need to be considered in the nearshore wave simulations.

3

Shallow-water wave energy dissipation in a multi-bar coastal zone

Pruszak Z., Szmytkiewicz P., Ostrowski R., Skaja M., Szmytkiewicz M.

Oceanologia

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2008

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No. 50 (1)

43-58

EN

The paper presents the results of studies of wave transformation on a multi-bar cross-shore profile of the southern Baltic Sea. The field investigations of wave motion were carried out using an offshore wave buoy and string wave gauges at the IBW PAN Coastal Research Station, Lubiatowo (Poland). These experimental results were used to validate statistical relationships between characteristic wave parameters in the coastal region and to assess wave energy dissipation in the surf zone. A simple model for calculating the residual nearshore wave energy is proposed and tested versus the data collected in situ.

4

Studies of aerosol physical properties in the coastal area

Zielinski T, Petelski T

Optica Applicata

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2006

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Vol. 36, nr 4

s. 629--634

EN

In the marine boundary layer over coastal areas marine aerosol size distribution and concentration strongly depend on wind speed and location of the measuring point accross the surf zone. The measurements were taken from several stations on the Polish coast of the Baltic Sea by means of the lidar system FLS-12 and the laser particle counter CSASP-100-HV-SP. The results obtained provide valuable inputs for investigations of the physical processes, as well as an important data set for use in the development of aerosol type modeling and aerosol dynamics in the coastal areas.

5

Zonation of macrofauna across sandy beaches and surf zones along the Dutch coast

Janssen G., Mulder S.

Oceanologia

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2005

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No. 47 (2)

265-282

EN

On nine beaches and two transects in the surf zone along the Dutch coast the presence of benthic macrofauna was studied in relation to basic abiotic characteristics. According to Short's classification system, Dutch beaches are mesotidal and dissipative (? = 8.6), and the RTR is low (1.52-1.27), which means that they are not tide-dominated. BSI ranged from 1.4 to 1.1 for the northern and western Dutch coasts respectively and had an overall value of 1.2. The rates of exposure of the beaches varied between 8 and 12, and are therefore regarded as sheltered to moderately exposed. The Dutch beaches display a geographical trend in beach types. Those of the Wadden Sea islands in the northern part of the Netherlands are dissipative, flat, fine-grained, and host high densities of many species of benthic macrofauna. The beaches along the western Dutch coast are less dissipative, steeper, with a higher mean grain size; the species diversity and abundance there are lower. Species diversity and abundance on the beaches increase from the high- to the low-water line. The maximum number of species was found between 0 and -1 m relative to the mean tidal level. The abundance peaks just above the mean tidal level, while the biomass reaches a maximum at the mean tidal level. Species diversity and abundance are low in the surf zone, but increase towards deeper water. Species numbers are high and the abundance is very high in the trough between the two bars. The relation between the diversity and abundance of macrobenthic species on the one hand, and the sediment composition, water column depth, and position between the bars on the other show a clear pattern of zonation for the beach, surf zone and near-shore: (1) a supralittoral zone with insects and air-breathing crustaceans, (2) a midshore zone, with intertidal species, (3) a lower shore zone, whose species extend into the shallow surf zone, and (4) a zone of sublittoral fauna in the trough between the two breaker bars within the surf zone.

6

Variations in the physical properties of surf generated aerosols with altitude

Zieliński T.

Oceanologia

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2003

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No. 45 (4)

643-653

EN

Vertical profiles of marine aerosol size distribution and concentration in the marine boundary layer over surf zones depend strongly on wind speed, direction and duration as well as the sea bottom profile. The measurements in the present study were carried out in various seasons of the year with all these factors being taken into consideration. The data with respect to offshore winds were neglected in the calculations, since in such cases the major aerosol contribution was from terrigenous and anthropogenic particles. It was confirmed that in the range of wind speeds from 1 m s-1 to 12 m s-1 there were measurable differences in the concentrations, particularly in the size distribution of marine aerosol particles at two stations differing with respect to their sea bottom profiles.

7

Dependence of the surf zone aerosol on wind direction and wind speed at a coastal site on the Baltic Sea

Zieliński T.

Oceanologia

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2003

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No. 45 (3)

359-371

EN

Since 1992 lidar-based measurements have been carried out under various meteorological conditions and at various times of the year. The aerosol optical properties were determined in the marine boundary layer as a function of altitude using such factors as wind direction, duration and velocity and aerosol size distribution and concentration. It was confirmed that in all cases, the total aerosol concentration, size distribution and aerosol extinction increase with wind speed but decrease with altitude. In the range of wind velocities from 1 to 15 m s-1 the mean aerosol optical thickness of the atmosphere (VIS) obtained from the lidar varied from 0.1 to 0.38 for offshore winds and from 0.01 to about 0.1 for onshore winds, while the Angström parameter for VIS oscillated around 0.65 for onshore winds and around 1 for offshore winds. Both parameters depended strongly on the history of the air mass above the Baltic Sea. Such aerosol optical thicknesses are in agreement with those obtained by other researchers in the Baltic Sea area.

8

Application of numerical wave model swan for analysis of waves in the surf zone

Reda A., Paplińska B.

Oceanological Studies

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2002

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Vol. 31, No. 1-2

5-21

EN

The numerical wave model SWAN has been used for wave modelling at the Coastal Research Facility at Lubiatowo. This study tested the performance of SWAN in the surf zone with four longshore bars. This is the first stage of the work heading towards a widening of the wave forecast for the Polish nearshore. The analysis concerned changes in the space and time of chosen wave parameters: significant wave height, mean wave period, mean wave direction. Modelled wave parameters were compared with measurements taken during the field experiment in 1996. The conformity is generally reasonable although the model tends to underestimate the significant wave height, particularly for higher waves. Further studies are planned to determine the reason behind this phenomenon.