Analysis of the wind regime and dune morphology within the Namib Sand Sea

This study examines the relationship between the wind regime of the Namib Desert and the morphology of the sand dunes found within the Namib. Typically, research in dune morphology involves gathering wind data from wind stations found in the study area. However, in the Namib Desert there are only a few weather stations. To address this problem, this study follows the previous work of Almutlaq (217) using the Global Ensemble Forecast System (GEFS) to create virtual wind stations. With these virtual wind stations, Fryberger’s (1979) methods of calculating the drift potential (DP), resultant drift potential (RDP), and the RDP/DP ratio are used to quantify the effective wind regime of the sand sea. The main objectives are to: 1) visually classify and map the main dunes types of found within the desert, 2) use wind data from the GEFS model to calculate and map the monthly RDP and RDP/DP ratios at a 0.5º spatial resolution, 3) aggregate and map these monthly RDP and RDP/DP ratios to characterize the annual wind regime and 4) relate these RDP and RDP/DP ratios to the varied dune morphology. The results from this study are presented in a map categorizing the different dune types found in the Namib, a map of dune height, and monthly and annual maps showing the effective wind regime as represented by the RDP and RDP/DP ratios. Overall, the types of dunes found in the Namib are consistent with the expected nature of the wind regime. The transverse dunes in the western part of the sand sea are formed by unidirectional winds, the linear dunes in the central part of the sand sea are formed in by acute bimodal winds, and the star dunes in the eastern part of the sand seas are formed by multidirectional winds.