Issaouane Erg confined to basins. Sand in the Issaouane Erg, below the level of the sand dunes, has accumulated to a depth of 20 to 30 meters. It has barchan dunes as well as star dunes of 300 to 430 meters high. The presence of both barchan dunes (which form due to unidirectional winds) and star dunes (which form when winds from various directions deposit sand) "suggests that wind regimes have changed over time". NASA's "Earth Observatory" notes all three types of erg dunes are present in the photos of the Issaouane Erg taken from the International Space Station: stationary mega dunes,
International Association of Arabic Dialectology International Association of Arabic Dialectology The International Association of Arabic Dialectology (, AIDA) is an association of researchers in Arabic dialects, from all over the world. AIDA was founded in 1992, in Paris, at the initiative of a group of prestigious Arabists, with the aim to encourage and promote the study of Arabic dialects. AIDA is nowadays the leading international association in this field of research and it has become a center that joins scholars from all over the world who are interested in any aspect of Arabic dialectology, including dialects which have not been described yet, dialectal geography, specific