A high spatio-temporal methodology for monitoring dunes morphology based on precise GPS-NRTK profiles: Test-case of Dune of Mَnsul on the south-east Spanish coastline

The effects of erosion and accretion of sand dune systems are often underestimated due to the coarse spatial and temporal resolution data set. This paper shows a specific methodology to monitor, at local scale and high repeatability, the crescentic dune of Mónsul in Almería (SE Spain). Precise spatial information based on high resolution profiles has been obtained periodically by repeated GPS surveys. The dune morphology and associated changes due to erosion and accretion are investigated using the GPS methodology in RTK (Real Time Kinematic) mode. This technique introduces significant improvements compared to other techniques for monitoring small areas such as better repeatability, accuracy, reliability, etc. The availability of the Andalusian Positioning Network, an active network over the region, allowed us to monitor the dune throughout GPS profiles capturing its evolution for the period of April–September, 2010. Three GPS campaigns spaced over time were performed. The framework is established by the active network, avoiding the placement of a local control network in this protected area. The main objective of this study is to perform a control methodology based on NRTK (network RTK) positioning supported by a regional active network, with special emphasis on checking and filtering the surveyed data. The numerical and graphical results presented show a balance between the values of erosion and accretion of sand on the dune.