INFLUENCE OF MORPHOLOGY ON WIND FLOW AND SEDIMENT TRANSPORT PATTERNS ON TWO AQUITAINE COASTAL DUNES (SW, FRANCE)

Across the coastal dunes, wind velocity and consequently sand transport is strongly controlled by the interaction between regional wind flow, vegetation cover and surface topography (topographic steering, Schwarz et al., 2020). Recently, knowledge has been improved on how winds erode, transport and deposit sand across coastal dunes, including the specific effects of vegetation and moisture as exemple (e.g Bauer et al., 2012; Hesp et al., 2015; Davidson et al., 2022). However, most of the existing studies are based on measurements collected along a single profile, thus limiting the understanding of alongshore variability and of the influence of the beach-dune profile on windblown sand pathways. The aim of this study is to address the differences on the wind flow pattern and resulting sediment transport during the same storm events at two beach-dune systems separated by only 7 km. The two field sites, which are exposed to the same ambient wind conditions, have contrasting dune profile morphologies primarily due to different human action (fixation/remobilization), allowing to discuss the impact of coastal dune management on aeolian processes.