Uncovering complex star dune dynamics using dense spatiotemporal 3D monitoring

• Applicants: Professorin Dr. Katharina Anders; Dr. Manuel Herzog
• Subject Area: Physical Geography ; Geodesy, Photogrammetry, Remote Sensing, Geoinformatics, Cartography
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 551866032

The proposed research project aims to understand complex mega dune dynamics, with a strong focus on star dunes as occur in the Namib Sand Sea. Star dunes form under complex multivariate environmental conditions and remain poorly understood compared to simple dune forms. However, recent findings indicate that star dunes are more active and younger than previously assumed and will, due to climate change and the associated expansion of sand seas, pose significant challenges to infrastructure and livelihoods. It is therefore crucial to better comprehend the dynamic behaviour of these landforms. For this, our project investigates the present aeolian dynamics of star dunes. This will increase our understanding of their formation and contribute valuable insights for hazard assessment and risk mitigation. Known general controls for star dune formation are the influence of regional wind systems, sediment availability and the location in depositional centres. However, existing studies remain in a descriptive state until now. Comprehensive and frequent quantitative monitoring of these dunes is lacking so far, which hinders the validation and extension of current development theories. To address this research gap, we conducted preliminary studies using a novel strategy based on multitemporal high-resolution topographic 3D measurements, which were combined with time series records of local wind dynamics. This approach showed the potential to detect surface changes in unprecedented spatiotemporal detail for the observation of surface and volume dynamics, which is crucial for the understanding of sand transport processes in general. Our findings, beside annual and seasonal dune changes, led to the formation of a new hypothesis regarding a self-sustained mechanism for dune growth due to a shielding effect on windward slopes. The main objective of the project is a repeated monitoring and analysis of mega dune dynamics through frequent laser scanning using Unoccupied Aerial Vehicles (UAVs) in correlation to the local and regional wind system, and the development of automatic measurement algorithms. Star dunes in the Namib are ideal for this purpose. The aeolian dynamics, including surface and volume changes, can be linked to the observed wind system and the underlying mechanisms can be deduced. Finally, the detailed quantitative spatial and temporal recording of the boundary conditions of sand transport allows insights into the formation and potential development and, for example in the context of climate change, possible future changes of star dunes in particular and megadunes in general to be derived.

• DFG Programme: Research Grants
• Co-Investigator: Professor Dr. Olaf Bubenzer