Dunes on planet Tatooine: Observation of barchan migration at the Star Wars film set in Tunisia

Sand dune migration is documented with a readily-available tool (Google Earth) near Chott El Gharsa, just north-west of Tozeur, Tunisia. As fiducial markers we employ a set of buildings used to portray the fictional city Mos Espa. This set of ~ 20 buildings over roughly a hectare was constructed in 1997 for the movie Star Wars Episode 1 — The Phantom Menace. The site now lies between the arms of a large “pudgy” barchan dune, which has been documented via satellite imaging in 2002, 2004, 2008 and 2009 to have moved from ~ 140 m away to only ~ 10 m away. Visits by the authors to the site in 2009 and 2011 confirm the barchan to be in a threatening position: a smaller set nearby was substantially damaged by being overrun by dunes circa 2004. The migration rate of ~ 15 m/yr decreases over the observation period, possibly as a result of increased local rainfall, and is consistent with barchan migration rates observed at other locations worldwide. The migration rate of this and two other barchans suggests sand transport of ~ 50 m3/m/yr, somewhat higher than would be suggested by traditional wind rose calculations: we explore possible reasons for this discrepancy. Because of the link to popular science fiction, the site may be of pedagogical interest in teaching remote sensing and geomorphic change. We also note that nearby playa surfaces and agricultural areas have a time-variable appearance. The siteʹs popularity as a destination for Star Wars enthusiasts results in many photographs being posted on the internet, providing a rich set of in-situ imagery for continued monitoring in the absence of dedicated field visits.