Wind Influence on the Formation of Nearshore Currents in the Southern Baltic: Numerical Modelling Results

Abstract

A two-dimensional numerical model was used for a simulation of vertical average longshore currents generated by both wind friction and wind-wave action in the nearshore zone. The modelling domain includes the southern part of the Baltic Proper (all boundaries were closed). Wind, uniform in space and varying in time, was the only forcing in the model. The correlation coefficient higher than 0.8 was obtained by model calibration versus the field measurements of currents conducted at the Lubiatowo field station (southern Baltic) during about 1.5 months in 2006. Comparative simulations of total currents including both wind-induced drift and wave components, and of total currents including only a wind-induced drift component, showed that the input of the drift component into currents in the nearshore zone is greater than commonly believed.Wind-induced drift strongly dominates outside the zone of wave transformation, and its input into the total resulting currents remains noticeable even in a zone between the shoreline and the depth of the first wave breaking. Thus, wind-induced drift constitutes up to 50% of the resulting longshore currents for longshore winds and no less than 20% of the longshore component of currents for winds at 45 degrees to the longshore direction.

Simulating Flow of An Urban River Course with Complex Cross Sections Based on the MIKE21 FM Model

“…The numerical calculation accuracy of the MIKE21 FM model is becoming more and more recognized. Gayer et al, simulated the influence of eddy current and roughness coefficient in the tsunami model with the MIKE21 FM model, and the calculated results were nicely consistent with the measured data [34]; Sokolov et al, carried out a simulation analysis with the measured data of the Baltic Sea collected by the Polish Academy of Sciences and found out that the correlation between the simulation results and the measured results was up to 0.86 [35]; Pedersen et al, carried out a simulation analysis with the measured tsunami data along the northern coast of Sumatra and found out that the simulation results were basically consistent with the measured data after several times of debugging [36]. Xie et al, determined the model parameters based on flooding data of the Luanhe River measured in 2012 to make the simulated flood level agree well with the measured flood level hydrograph [37].…”

Case-Study Modelling Analysis of Hydrodynamics in the Nearshore of the Baltic Sea Forced by Extreme Along-shore Wind in the Case of a Cross-shore Obstacle

“…Therefore, it was assumed that wind was uniform in speed and direction over the entire simulation area (Soomery 2001). The above model setup showed (Sokolov, Chubarenko 2018) its advantages for coupled hydrodynamic and wind-wave simulations near the shore and was proposed for the first time in (Sokolov, Chubarenko 2012).…”

“…The calibration of the hydrodynamic module (Sokolov, Chubarenko 2018) was based on field data collected by the Institute of Hydro-Engineering of the Polish Academy of Sciences (IBW PAN) in the vicinity of the Lubiatowo Field Station (South-Eastern Baltic) between October 1 and November 22, 2006 (Pruszak et al 2008): the speed of currents at ordinates from 0.4 m to 2.4 m above the bottom were measured by an ADCP located 200 meters from the shoreline at a depth of 4-4.4 m, depending on water level variations; the wind data were provided by an automated meteorological station. The first results of the calibration and verification of the model setup for depth-averaged currents were presented in (Sokolov, Chubarenko 2012).…”

Dynamics of sediments disposed in the marine coastal zone near the Vistula Lagoon inlet, south-eastern part of the Baltic Sea

“…The wind was the single external force; it had uniform velocity and direction for the whole domain and was equal to the wind measured at Baltiysk. Such a model set-up showed its advantages for pure hydrodynamic simulations near the shore of the study area in (Sokolov, Chubarenko 2012).…”

“…The results of the calibration of the utilised model setup of the hydrodynamic and spectral wave modules were presented in (Sokolov, Chubarenko 2012) and (Sokolov, Chubarenko 2014), respectively: the correlation coefficients between the measured and simulated currents and waves were up to 0.8, and maximal and average values were also comparable. All coefficients obtained during these studies were used in the simulations described below.…”