Profile measurement and simulation of a transverse dune field in the Lençóis Maranhenses

Abstract

In this work, we report measurements of the height profile of transverse dunes in the coastal dune field known as ``Lençóis Maranhenses'', northeastern Brazil. Our measurements show that transverse dunes with approximately the same height present a variable brink position relative to the crest, in contrast to the case of barchan dunes. Based on our field data, we present a relation for the dune spacing as a function of the crest-brink distances of transverse dunes. Furthermore, we compare the measurements with simulations of transverse dunes obtained from a two-dimensional dune model, where a phenomenological definition is introduced for the length of the separation streamlines on the lee side of closely spaced transverse dunes. We find that our model reproduces transverse dune fields with similar inter-dune distances and dune aspect ratios as measured in the field.