Principal Component and Cluster Analysis for determining diversification of bottom morphology based on bathymetric profiles from Brepollen (Hornsund, Spitsbergen)

Abstract

Navigation charts of the post-glacial regions of Arctic fjords tend not to cover regions from which glaciers have retreated. Whilst research vessels can make detailed bathymetric models using multibeam echosounders, they are often too large to enter such areas. To map these regions therefore requires smaller boats carrying single beam echosounders. To obtain morphology models of equivalent quality to those generated using multibeam echosounders, new ways of processing data from single beam echosounders have to be found. The results and comprehensive analysis of such measurements conducted in Brepollen (Hornsund, Spitsbergen) are presented in this article. The morphological differentiation of the seafloor was determined by calculating statistical, spectral and wavelet transformation, fractal and median filtration parameters of segments of bathymetric profiles. This set of parameters constituted the input for Principal Component Analysis and then in the form of Principal Components for the Cluster Analysis. As a result of this procedure, three morphological classes are proposed for Brepollen: (i) steep slopes (southern Brepollen), (ii) flat bottoms (central Brepollen) and gentle slopes (the Storebreen glacier valley and the southern part of the Hornbreen glacier valley), (iii) the morphologically most diverse region (the central Storebreen valley, the northern part of the Hornbreen glacier valley and the north-eastern part of central Brepollen).