Morphological study of the sand dunes in Zarrin Erg and its adaptation to the regional wind data

The purpose of this study is to investigate the morphology of the sand dunes located in Zarin Erg in the northwest of the city of Yazd and its accordance with the wind data provided by the surrounding synoptic stations. The results showed that the sand dunes have different morphologies, including simple dunes, seif, barchans, star, and complex dunes. The complexity and variety of the dunes indicates the drastic variation of wind regimes seasonally, annually as well as periodically. Also, they do not match with any wind data of the surrounding synoptic stations. The presence of barchans in the quadrilateral erg is indicative of directional winds. The local winds are the main cause of the formation of these dunes and their morphology. Indeed, due to the difference of height between the central Iranian playas and upstream mountainous, the playas of this part of Iran often serve as thermal low-pressure centers on the Earth surface, and their marginal sand dunes are always moved by these winds. The accumulation of large amounts of sand in the southeastern part of the erg and the formation of star dunes with a height of more than 200 meters are signs of prevailing north-west winds in the warm season and the severe winds of the southeast in the cold season. These winds reinforce the power of local convergent winds.