Jaroslaw Tegowski
University of Gdansk, Department of Marine Geology, Faculty Member
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The process of wave breaking and whitecap creation is one of the most important and least understood phenomena associated with the evolution of the surface gravity waves in the open sea. This process is the main way of energy and momentum... more
The process of wave breaking and whitecap creation is one of the most important and least understood phenomena associated with the evolution of the surface gravity waves in the open sea. This process is the main way of energy and momentum transfer between ocean and atmosphere. However, it is very difficult to estimate, under real sea conditions, the frequency of breaking wave events or the fraction of sea surface covered by whitecaps and the amount of dissipated energy produced by wave breaking. A controlled experiment was carried out in the Ocean Basin Laboratory at MARINTEK, Trondheim (Norway). The simulation of random waves of the prescribed spectra provided a very realistic pattern of the sea surface. The number of breaking waves was estimated using photography method and wave staff recording. Acoustic measurements during the experiments were conducted in order to examine the relationship between the noise spectral parameters and both the whitecap coverage and dissipation energy of breaking waves for different types of waves. A comparison of simultaneous video observations, wave staff records of the surface wave above the hydrophones, with the spectral parameters of acoustical signals made it possible to find physical links between processes.
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Abstract: On twelve testing fields located in the main water basins of the Gdańsk and Szczecin harbours, the efficiency of a new depth technique was verified. The technique that determines a safe nautical depth is defined by a density... more
Abstract: On twelve testing fields located in the main water basins of the Gdańsk and Szczecin harbours, the efficiency of a new depth technique was verified. The technique that determines a safe nautical depth is defined by a density criterion of a mud-water medium. The ...
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This is a brief review paper on measurements of acoustical properties of sediments in the Polish economic zone of the Baltic Sea. Maps of the distributions of backscattering coefficient and attenuation at 30 kHz are presented. Angular... more
This is a brief review paper on measurements of acoustical properties of sediments in the Polish economic zone of the Baltic Sea. Maps of the distributions of backscattering coefficient and attenuation at 30 kHz are presented. Angular dependences of the backscattering coefficient at 50 kHz and their comparison with theoretical model is also mentioned.
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Research Interests: Archaeology, Geology, Oceanography, Quaternary, Sediment, and 3 moreBaltic Sea, Echo Sounding, and Seabed
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Abstract-The response of a reflecting boundary, such as an ocean bottom, to an impinging acoustic pulse involves several processes and variables. One group of these processes is associated with the formation of an acoustic... more
Abstract-The response of a reflecting boundary, such as an ocean bottom, to an impinging acoustic pulse involves several processes and variables. One group of these processes is associated with the formation of an acoustic transmittinglreceiving beam and with the parameters of ...
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Abstract: This paper deals with some aspects of the wave-breaking phenomenon. The objectives were to study wave-breaking criteria, and the probability of whitecap coverage under fully controlled wave conditions. An additional task was to... more
Abstract: This paper deals with some aspects of the wave-breaking phenomenon. The objectives were to study wave-breaking criteria, and the probability of whitecap coverage under fully controlled wave conditions. An additional task was to investigate the characteristic spectral features ...
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ABSTRACT Transitional environments like lagoons, deltas and estuaries often undergo strong natural and human-induced actions that need constant monitoring. The changes of these environments can be assessed using acoustic bathymetric... more
ABSTRACT Transitional environments like lagoons, deltas and estuaries often undergo strong natural and human-induced actions that need constant monitoring. The changes of these environments can be assessed using acoustic bathymetric surveys: bathymetric data are not only important for navigational purposes but they are also employed for geomorphologic studies, habitat mapping and modelling of evolution trends of the highly dynamical coastal areas. Among the coastal systems, transitional environments, are often extremely shallow (of the order of 1 m deep or less) and morphologically complex. This kind of environment represents a challenge for acoustic bathymetric surveys. To assess the potentiality and the limits of acoustic surveys in extremely shallow environments, we carried out two surveys in the Lagoon of Venice, Italy, with an interferometric sonar and a multibeam echosounder system. As a case study we focused on a natural channel in the northern part of the lagoon combining the data from the different surveys. In particular we carried out a two-dimensional (2D) spectral and textural analysis of the high resolution bathymetric and backscatter data collected. As a result of the 2D spectral analysis on the elevation data, we were able to identify and parameterize the geometrical characteristics of the main morphological features of the channel, like dunes, scours, crests and troughs and sedimentation areas and to extract the channel bottom roughness. We then performed an unsupervised classification of the backscatter data. As a result, we were able to identify different backscatter areas where several grab samples were collected for ground truthing. With the help of this sampling we calibrated a textural analysis and obtained a classification of the different kinds of substrate. Within this multidisciplinary approach, we set up and successfully tested a combined method to quantitatively characterize an extremely shallow water dynamical environment. Using this method, we could map the main morphological and sedimentological features of the seabed and relate them to the hydrodynamic conditions provided by an high resolution 3D numerical model.
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The main purpose of this research is to develop efficient and reliable acoustic techniques for monitoring geomorphological and sedimentary features of the Baltic seabed. Multibeam echosounder (MBES) measurements were carried out in the... more
The main purpose of this research is to develop efficient and reliable acoustic techniques for monitoring geomorphological and sedimentary features of the Baltic seabed. Multibeam echosounder (MBES) measurements were carried out in the Baltic Sea at the Rewal area, which is characterized by diversified types of sediments, geomorphologic forms, and benthic habitats. An MBES provides two types of information - bathymetric data needed for the digital elevation model (DEM) construction, and relative backscattered intensity of the acoustic signal. The seabed features were extracted using a 2D Fourier transformation of the DEM. Spectral parameters of bottom rough surface were used for the classification of seafloor morphological types using a fuzzy logic classification algorithm. The other method was used for backscatter intensity, where the spectral parameters of angular dependency of bottom backscattered intensity were the input to the classification algorithm. The results of both methods were compared with the sedimentological information of the analysis of 56 sediment samples, and a good compatibility of the classifications was obtained.
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... 100 200 300 400 500 600 700 800 900 1000 increasing size for each image region were used to find characteristic granulometric curves. Curve shapes are ... 200 elements of increasing size for each image region are used to find... more
... 100 200 300 400 500 600 700 800 900 1000 increasing size for each image region were used to find characteristic granulometric curves. Curve shapes are ... 200 elements of increasing size for each image region are used to find characteristic granulometry curves. 300 ...
Research Interests: Geography, Geology, Oceanography, Remote Sensing, Climate Change, and 15 moreSonar, Mathematical Morphology, Global Warming, Arctic, Underwater, Comparative Analysis, Spatial Distribution, Fjord, Texture Analysis, Oceans, Echo Sounding, Classification Algorithm, OCEANS Conference, Seafloor Spreading, and Parametric analysis
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Anthropogenic underwater noise is an emergent pollutant and several monitoring programs have started worldwide. However, only few data are available so far for the Mediterranean Sea, one of the global biodiversity hotspots. To fill this... more
Anthropogenic underwater noise is an emergent pollutant and several monitoring programs have started worldwide. However, only few data are available so far for the Mediterranean Sea, one of the global biodiversity hotspots. To fill this knowledge gap, this study presents the results of the first continuous acoustic monitoring run at a transnational basin scale in the Mediterranean Sea between March 2020 and June 2021, including the COVID-19 lockdown, at nine stations in the Northern Adriatic Sea. Median yearly sound pressure levels (SPLs) ranged between 64 and 95 as well as 70 and 100 dB re 1µPa for 63 and 125 Hz third octave bands, respectively. Although these values are comparable with those previously found in busy shallow EU basins, higher levels are likely to be found during a business-as-usual period. Higher and more variable SPLs, mainly related to vessel traffic were found in stations close to important harbours, whereas stations inside or close to Natura 2000 sites, experie...
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Management of the impact of underwater sound is an emerging concern worldwide. Several countries are in the process of implementing regulatory legislations. In Europe, the Marine Strategy Framework Directive was launched in 2008. This... more
Management of the impact of underwater sound is an emerging concern worldwide. Several countries are in the process of implementing regulatory legislations. In Europe, the Marine Strategy Framework Directive was launched in 2008. This framework addresses noise impacts and the recommendation is to deal with it on a regional level. The Baltic Sea is a semienclosed area with nine states bordering the sea. The number of ships is one of the highest in Europe. Furthermore, the number of ships is estimated to double by 2030. Undoubtedly, due to the unbound character of noise, an efficient management of sound in the Baltic Sea must be done on a regional scale. In line with the European Union directive, the Baltic Sea Information on the Acoustic Soundscape (BIAS) project was established to implement Descriptor 11 of the Marine Strategy Framework Directive in the Baltic Sea region. BIAS will develop tools, standards, and methodologies that will allow for cross-border handling of data and results, measure sound in 40 locations for 1 year, establish a seasonal soundscape map by combining measured sound with advanced three-dimensional modeling, and, finally, establish standards for measuring continuous sound. Results from the first phase of BIAS are presented here, with an emphasis on standards and soundscape mapping as well as the challenges related to regional handling.
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This is a brief review paper on measurements of acoustical properties of sediments in the Polish economic zone of the Baltic Sea. Maps of the distributions of backscattering coefficient and attenuation at 30 kHz are presented. Angular... more
This is a brief review paper on measurements of acoustical properties of sediments in the Polish economic zone of the Baltic Sea. Maps of the distributions of backscattering coefficient and attenuation at 30 kHz are presented. Angular dependences of the backscattering coefficient at 50 kHz and their comparison with theoretical model is also mentioned.
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The fractal dimension of 30 kHz echo envelope is used for characterise the bottom sediment type in Southern Baltic Sea. Twa methods of the echo waveform fractal dimension calculation were applied: the autocorrelation function log-log... more
The fractal dimension of 30 kHz echo envelope is used for characterise the bottom sediment type in Southern Baltic Sea. Twa methods of the echo waveform fractal dimension calculation were applied: the autocorrelation function log-log slope method and the power spectrum log-log slope method. The results are presented and compared. They show that fractal dimension of echo envelope describes well the bottom sediments morphology and may be used as a significant descriptor in the remote sea bed classification procedures.
The main purpose of this research is to develop efficient and reliable acoustic techniques for monitoring geomorphological and sedimentary features of the Baltic seabed. Multibeam echosounder (MBES) measurements were carried out in the... more
The main purpose of this research is to develop efficient and reliable acoustic techniques for monitoring geomorphological and sedimentary features of the Baltic seabed. Multibeam echosounder (MBES) measurements were carried out in the Baltic Sea at the Rewal area, which is characterized by diversified types of sediments, geomorphologic forms, and benthic habitats. An MBES provides two types of information - bathymetric data needed for the digital elevation model (DEM) construction, and relative backscattered intensity of the acoustic signal. The seabed features were extracted using a 2D Fourier transformation of the DEM. Spectral parameters of bottom rough surface were used for the classification of seafloor morphological types using a fuzzy logic classification algorithm. The other method was used for backscatter intensity, where the spectral parameters of angular dependency of bottom backscattered intensity were the input to the classification algorithm. The results of both methods were compared with the sedimentological information of the analysis of 56 sediment samples, and a good compatibility of the classifications was obtained.
Research Interests: Geology and Echo Sounding
High-latitude regions like the Arctic Ocean are becoming increasingly important as global warming makes them more accessible, raising economic and political interests. Sea ice reduction is facilitating resource exploration, marine... more
High-latitude regions like the Arctic Ocean are becoming increasingly important as global warming makes them more accessible, raising economic and political interests. Sea ice reduction is facilitating resource exploration, marine transport and other activities. Warming waters and changing sea ice conditions lead to shifts in ecosystems. Resource exploitation will grow in the coming decades, offering new opportunities but also new challenges to these fragile environments and their biodiversity. The natural and anthropogenic changes in this region will change the characteristics of soundscapes. To measure and assess them at a variety of spatial and temporal scales, the International Quiet Ocean Experiment created in 2017 a working group on Arctic Acoustic Environments. First activities focus on synthesising state-of-the-art knowledge of Arctic sounds—past, present and future. WG activities were presented at the Arctic Observing Summit 2018 and its recommendations adopted at the 2nd A...
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Growing scientific and societal concerns about the effects of underwater sound on marine ecosystems is now recognised through several international initiatives aiming at measuring the environmental impact of ocean noise at large spatial... more
Growing scientific and societal concerns about the effects of underwater sound on marine ecosystems is now recognised through several international initiatives aiming at measuring the environmental impact of ocean noise at large spatial and temporal scales. This pressure and these concerns are particularly acute in the Polar Regions (Arctic and Antarctic), where climate change and increased human presence add new variables to little studied, and complex environments. Sea ice reduction is facilitating resource exploration, marine transport and other economic activities (e.g. fishing) in these regions, adding to ambient noise. In the last decade, there has also been significant growth in offshore oil and gas exploration in several Arctic regions. An assessment made by the US Geological Survey estimates that 30% of the world’s undiscovered gas and 13% of the undiscovered oil are located in the Arctic (Klett and Gautier et al., 2009).Similarly, the Barents Sea is the most important fish...