An object method to characterize grainflow morphology

Abstract

<p>Grainflow, a fundamental agent moving sediment from the crest to the base of dune surfaces, leaves a temporary geomorphological signature on the slipfaces of aeolian dunes. The grainflow signature reflects the complex morphodynamical interaction between wind-driven sand transport and gravity-driven grainflow on an inclined surface. The purpose of this study is to present a method to objectively and efficiently delineate grainflow boundaries and characterize their morphology features by processing Digital Elevation Models (DEMs) obtained by terrestrial laser scanner in Matlab and ArcGIS. The method allows large numbers of grainflows to be quickly and objectively delineated and extracted from LiDAR data. As an aid tp subsequent analysis, the process avoids the subjective nature of manual measurement, thereby improving the commensurability of different grainflow regimes in both terrestrial and extraterrestrial environments. The results can be compared with the available grainflows morphology characteristics which are manually measured. The method is presented here in the context of analyzing grainflows and related processes on the slipfaces of dunes, but it is applicable over the broader scope of other forms of slope failure and geophysical flows, such as avalanches, snowslides, landslides, and debris flows.</p>