Abstract: Desertification of the Otindag Sandy Land is mainly manifested by the reactivation of fixed sand dunes caused by the development of blowouts. This paper uses the high-resolution satellite image data and ground survey data in 2010, 2013 and 2016. The visual interpretation method, under the support of The ArcGIS software, is used to analyze the dynamic changes of blowouts and how they are related to the climatic factors and human activities. According to the development site and geometry of the fixed sand dunes, the blowouts can be divided into a saucer shape, a bowl shape, a trough shape, a dustpan shape and an irregular shape. In 2010-2016, the various forms of blowouts grow mainly through expansion and reborn, leads to an increase in the total area and number. During 2010-2013, the area expanded by 6.47 hm² and added 11 more new-born blowouts. From 2013 to 2016, the area increased by 4.89 hm² and the number increased by 7. With little disturbance of human activity, the growth of blowouts in this area is largely affected by the change of climate factors. The reduction in sand drift potential, as the dynamic factor of blowouts, only reduces the development rate and slows down the process. The shape of the blowout itself also works as the main influencing factor.

Key words: blowout, dynamic change, geometrical morphology