aeolian sand accumulation forms by barriers pattern (case study: Semnan)

Aeolian sand accumulation forms reflect the complex external environment within which the pattern evolves. This paper considers the forms, classification and possible removal region of a variety of aeolian sand forms which occur in association with obstacles features in the south Semnan. The aeolian sand accumulation forms in the south Semnan were studied through analysis and Interpretation of aerial photographs, field observations and Interpretation of Google Earth images in order to facilitate the investigation of their distribution patterns and classification. The results of this study showed that the total area covered by aeolian sand accumulation forms related to obstacles is about 1848ha.The aeolian sand accumulation forms are found at the study area are two type of related to obstacles, a) Topographic barriers, including: Leeward accumulations (Sand shadow, Sand drift and Lee dune) and climbing and falling dunes and b) Anchorage by vegetation including Nebka. Studies of variations in type and pattern of sand accumulation forms indicate that climbing and falling dunes are located mainly in hill regions, sand drift and lee dune in pediment and sand shadow, Nebka in plain. Morphology of sand accumulation forms and wind regime have shown that sand resources are from the north and southwest.

Keywords:

aeolian sand accumulation forms , obstacles features , climbing and falling dunes.