Comparison of Backscatter and Seabed Topographic Characteristics Recorded by Multibeam Echosounder at Rewal Area - Southern Baltic Sea

Abstract

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.