2025_programme: Spectral and wavelet parameterization of seafloor hydroacoustic imaging for identification of subglacial forms of the Baltic Sea

• Day: June 19, Thursday
    Location / Time: C. THALIA at 12:20-12:40
• Last minutes changes: -
• Session: 15. Seabed Acoustics
  Organiser(s): Megan Ballard, Kevin Lee, Nick Chotiros
  Chairperson(s): Nicholas Chotiros
• Lecture: Spectral and wavelet parameterization of seafloor hydroacoustic imaging for identification of subglacial forms of the Baltic Sea
  Paper ID: 2337
  Author(s): Marcelina Kasuła, Karolina Trzcińska, Jarosław Tęgowski
  Presenter: Marcelina Kasuła
  Abstract: Ice streams are zones of concentrated and rapid flow of ice masses. They formed characteristic subglacial forms on the bottom of the Baltic Sea, with a shape elongated in the direction of the ice flow. This study analyzes a digital elevation model constructed on the basis of bathymetric measurements performed with multibeam echosounders in areas of the South Baltic with dimensions of several hundred kilometers. The purpose of the study is to evaluate in detail the effectiveness of using hydroacoustic imaging to identify subglacial forms of seafloor relief. \nThe methods implemented include comparison of parameters of two-dimensional Fourier analysis of the seaflor DEM, such as spectral width, spectral moment of zero and second order, Q-factor, mean frequency, spectral skewness and fractal dimension. A square window of 200m x 200m was determined on the digital bottom model, which was moved over the study area with an overlap of 90%. In this window, using 2DFFT, the result of the power spectral density was calculated, through which cross sections were taken every 5°. A 180 cross sections were obtained, which were averaged and then the spectral parameters were calculated for them. In addition, spectral and wavelet parameters were calculated for bathymetric transects focusing on wavelet energies. Maps of the values of the specified parameters of the seafloor covered by ice streams in the past and neighboring areas were compared. The results demonstrate the high potential for identification of subglacial forms using spectral and wavelet parameters together with geological data and manual interpretation of the forms. The results obtained are helpful in understanding the geological history of a large area of the South Baltic seafloor and provide information on the distribution of ice streams in the past. This work was funded through the project STREAMBAL, funded by the National Science Centre (Project ID: UMO-2021/41/B/ST10/01086).\n
• Corresponding author: Ms Marcelina Kasuła
  Affiliation: Division of Geophysics, Faculty of Oceanography and Geography, University of Gdansk
  Country: Poland