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Wind influence on the formation of nearshore currents in the southern Baltic: mumerical modelling results

100%

Sokolov A. , Chubarenko B.

Archives of Hydro-Engineering and Environmental Mechanics

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2012

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tom Vol. 59, nr 1-2

37-48

EN

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.

2

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

100%

Sokolov A. , Chubarenko B.

Archives of Hydro-Engineering and Environmental Mechanics

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2018

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tom Vol. 65, nr 3

163--176

EN

In the current study we use a three-dimensional model with hydrodynamic and spectral wave modules operating in a coupled mode to simulate the response of currents and wind wave fields to winds of 20–25 m/sec offshore of the protective structure of the Saint Petersburg Flood Prevention Facility Complex. The model was calibrated against field data, which allowed us to obtain a tool describing storm situations in the eastern part of the Gulf of Finland with a satisfactory accuracy. The numerical modeling showed that the protective dam did not have a noticeable effect on the levels of stormsurge, significantwave height, or current speed in areas seaward of the dam. The increase in erosion processes on the southern shore of the easternmost part of the Gulf of Finland in recent past has most probably been related to other factors. We found that if a west or south-west wind of at least 25 m/s blows over the Baltic Sea for at least 16 hours, the level of storm surges seaward of the dam may reach 3 or more meters. An artificial strengthening of the coastline and the creation of shore protection structures are recommended.

3

Neophytic Coripsermum pallasii (Stev.) (Chenopodiaceae) invading migrating dunes of the southern coast of the Baltic Sea

80%

Dolnik C. , Peyrat J. , Volodina A. , Sokolov A.

Polish Journal of Ecology

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2011

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tom Vol. 59, nr 1

95-103

EN

Actively migrating dunes along the southern coast of the Baltic Sea have a very specific vegetation of annual pioneer plants, some of which are endemic to that area. This vegetation type was studied on the migrating dunes of the Łeba Bar (Poland) and the Curonian Spit (Russia and Lithuania) and is for the first time represented by 18 vegetation releves according to the Braun-Blanquet approach. Typical plants on bare soil of active migrating dunes and sand fields in Baltic dunes are the endemics Corispermum intermedium (Chenopodiaceae), Cakile maritima subsp. baltica (Brassicaceae), and Linaria loeselii (Scrophulariaceae). A comparison of our field investigations with literature records revealed a gradual replacement of C. intermedium by the neophytic Siberian bugseed Corispermum pallasii (syn. C. leptopterum). C. intermedium suffered from severe habitat loss by dune afforestation, while the ruderal weed C. pallasii expanded its distribution range in the 20th century to various open gravel and sand fields in Europe, including dunes of the Baltic coast. New concepts of coastal conservation management, including aspects of coastal dynamics and nature conservation of endemic species, should be applied to conserve the remaining populations of C. intermedium.

4

Neophytic Coripsermum pallasii (Stev.) (Chenopodiaceae) invading migrating dunes of the Southern coast of the Baltic Sea

80%

Dolnik C. , Peyrat J. , Volodina A. , Sokolov A.

Polish Journal of Ecology

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2011

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tom 59

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nr 1

EN

Actively migrating dunes along the southern coast of the Baltic Sea have a very specific vegetation of annual pioneer plants, some of which are endemic to that area. This vegetation type was studied on the migrating dunes of the Łeba Bar (Poland) and the Curonian Spit (Russia and Lithuania) and is for the first time represented by 18 vegetation releves according to the Braun-Blanquet approach. Typical plants on bare soil of active migrating dunes and sand fields in Baltic dunes are the endemics Corispermum intermedium (Chenopodiaceae), Cakile maritima subsp. baltica (Brassicaceae), and Linaria loeselii (Scrophulariaceae). A comparison of our field investigations with literature records revealed a gradual replacement of C. intermedium by the neophytic Siberian bugseed Corispermum pallasii (syn. C. leptopterum). C. intermedium suffered from severe habitat loss by dune afforestation, while the ruderal weed C. pallasii expanded its distribution range in the 20th century to various open gravel and sand fields in Europe, including dunes of the Baltic coast. New concepts of coastal conservation management, including aspects of coastal dynamics and nature conservation of endemic species, should be applied to conserve the remaining populations of C. intermedium.