Abstract:

The seafloor is characterised by active sand bodies of different scales, and  a large number of small-scale sand waves (ripples) is often superimposed on the large active sand bodies. The analysis of the small-scale sand waves (ripples) can reveal the genetic mechanism of these active sand bodies. However, their scales are small, and conventional analysis methods often filter them out as high-frequency noise, making it difficult to separate and quantify sand waves on the seafloor at this scale. To address this problem, a method was designed and implemented for decomposing small-scale submarine sand wave topography based on wavelet analysis, and achieved the decomposition and quantitative analysis of small-scale submarine sand wave topography: background topography, small sand waves and sand ripples (wavelength less than 0.6 m) by using high-precision bottommoored in situ observation data from a typical area of the Taiwan Banks. A quantitative method for decomposition of small-scale submarine sandwave topography was proposed, which can be widely applied to the study of the development and evolution of highly active landforms in shallow seas and the sediment dynamics of submarine boundary layer, and also has practical value for assessing the stability of marine engineering.

Key words: bottom-moored in situ observation, wavelet analysis, small-scale sand waves, sand ripples, Taiwan Bank