The dynamics of Pilkosios Dunes relief during 2010–2022, based on the digital elevation model analysis

Abstract

To assess aeolian relief dynamics in Pilkosios Dunes, 6 digital elevation models (DEMs) were prepared from the year 2010, for January, May and October of 2018, for May of 2019, and for November of 2022. These DEMs were then compared with each other to obtain elevation difference rasters through time. The obtained results indicated that elevation changes were directional through time, and their highest intensity coincided with the bare-sand surface class, where active blowout landforms were located. In these locations, the average negative elevation change rate was determined to be approximately 2 cm/year. To analyse the driving forces of these elevation changes, the relationships between a measure of elevation change and the tested factor characteristics were evaluated. The strongest relationship amongst all tested factors was found with the distance to the edge of grassland/bare sand. Locations that were farther away from this edge experienced a four times larger decrease in elevation, compared to areas closer to the edge. The distance to the shoreline, which is related to the absolute altitude, was also an important factor. This relationship can be summarized as follows: the lowest areas, which were further from the lagoon, were inactive; while the highest locations, which were closer to the shoreline, had the highest intensity of elevation change (averaging 0.5–0.7 m for adjacent to the shoreline locations and -1.7 m for locations ~ 300 m away from the shoreline). The slope factor described a trend of how the steepest slopes were decreasing in height by 2 m on average, while gentler slopes were mostly stable.