Wyniki wyszukiwania - Biblioteka Nauki

1

Nonlinear ship wake waves as a model of rogue waves and a source of danger to the coastal environment: a review

100%

Soomere T.

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2006

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tom No. 48 (S)

185-202

EN

A substantial part of the energy of wake waves from high-speed ships sailing in shallow water is concentrated in nonlinear components which at times have a solitonic nature. Recent results of investigations into solitonic wave interactions within the framework of the Kadomtsev-Petviashvili equation and their implications for rogue wave theory are reviewed. A surface elevation four times as high as the counterparts occurs if the properties of the interacting waves are specifically balanced. The slope of the water surface may increase eightfold. The resulting structure may persist for a long time. Nonlinear wake components may exert a considerable influence on the marine ecosystem in coastal areas .

2

The impact of fast ferry traffic on underwater optics and sediment resuspension

63%

Erm A. , Soomere T.

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2006

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tom No. 48 (S)

283-301

EN

Wake waves produced by fast ferries bring about significant changes in the optical parameters of sea water in the c. 1 m thick near-bottom layer of the coastal areas of Tallinn Bay. The greatest of these changes occur at relatively small depths, but the duration of the influence increases with increasing depth. Rough quantitative estimates suggest that the overall influence of fast ferry traffic in Tallinn Bay may result in an annual loss of the order of several hundred litres of fine sediments from each metre of the coastline.

3

The impact of fast ferry traffic on underwater optics and sediment resuspension

63%

Erm A. , Soomere T.

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nr S

EN

Wake waves produced by fast ferries bring about significant changes in the optical parameters of sea water in the c. 1 m thick near-bottom layer of the coastal areas of Tallinn Bay. The greatest of these changes occur at relatively small depths, but the duration of the influence increases with increasing depth. Rough quantitative estimates suggest that the overall influence of fast ferry traffic in Tallinn Bay may result in an annual loss of the order of several hundred litres of fine sediments from each metre of the coastline.

4

The progress in knowledge of physical oceanography of the Gulf of Finland: a review for 1997-2007

51%

Soomere T. , Myrberg K. , Leppäranta M. , Nekrasov A.

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tom No. 50 (3)

287-362

EN

The main findings of studies of the physical oceanography of the Gulf of Finland (GoF) during 1997-2007 are reviewed. The aim is to discuss relevant updates published in international peer-reviewed research papers and monographs, bearing in mind that a comprehensive overview of the studies up to the mid-1990s is available (Alenius et al. 1998). We start the discussion with updates on the basic hydrographical and stratification conditions, and progress in the understanding of atmospheric forcing and air-sea interaction. Advances in the knowledge of basin-scale and mesoscale dynamics are summarised next. Progress in circulation and water exchange dynamics has been achieved mostly by means of numerical studies. While the basic properties of circulation patterns in the gulf have been known for a century, new characteristics and tools such as water age, renewal index, and high-resolution simulations have substantially enriched our knowledge of processes in the Gulf of Finland during the last decade. We present the first overview of both status and advances in optical studies in this area. Awareness in this discipline has been significantly improved as a result of in situ measurements. Our understanding of the short- and long-term behaviour of the sea level as well as knowledge of the properties of both naturally and anthropogenically induced surface waves have expanded considerably during these ten years. Developments in understanding the ice conditions of the Gulf of Finland complete the overview, together with a short discussion of the gulf's future, including the response to climate change. Suggestions for future work are outlined.

5

Trends and extremes of wave fields in the north-eastern part of the Baltic Proper

45%

Broman B. , Hammarklint T. , Rannat K. , Soomere T. , Valdmann A.

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2006

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tom No. 48 (S)

165-184

EN

The paper analyses one of the longest contemporary wave measurements in the northern Baltic Sea, performed at Almagrundet 1978-2003. This record contains the roughest instrumentally measured wave conditions (significant wave height = c. 7.8 m) in the northern Baltic Proper until December 2004. The data for the years 1979-95, the period for which the data are the most reliable, show a linear rising trend of 1.8% per annum in the average wave height. The seasonal variation in wave activity follows the variation in wind speed. The monthly mean significant wave height varies from 0.5 m in May-July to 1.3-1.4 m in December-January. No corrections have been made in the analysis to compensate for missing values, for their uneven distribution, or for ice cover.

6

Trends and extremes of wave fields in the North-Eastern part of the Baltic Proper

45%

Broman B. , Hammarklint T. , Rannat K. , Soomere T. , Valdmann A.

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nr S

EN

The paper analyses one of the longest contemporary wave measurements in the northern Baltic Sea, performed at Almagrundet 1978–2003. This record contains the roughest instrumentally measured wave conditions (significant wave height = c. 7.8 m) in the northern Baltic Proper until December 2004. The data for the years 1979–95, the period for which the data are the most reliable, show a linear rising trend of 1.8% per annum in the average wave height. The seasonal variation in wave activity follows the variation in wind speed. The monthly mean significant wave height varies from 0.5 m in May–July to 1.3–1.4 m in December– January. No corrections have been made in the analysis to compensate for missing values, for their uneven distribution, or for ice cover.