The shape of the barchan dunes of Southern Morocco
نویسندگان
چکیده
We present detailed shape measurements of several barchan dunes in southern Morocco, near Laayoune. Using these ˆ data, we disprove the concept of shape invariance of barchan dunes of different sizes. Nevertheless, some parts of the barchan dune scale and we try to distinguish these from non-scaling ones. Furthermore, we point out the importance of the exact position of the brink for the overall dune shape. Finally, we propose a simple model for dune shape, using our data to determine the model parameters. Despite its simplicity, this model is able to explain the difference between barchans where the crest and the brink coincide and those where they are separated. Typical side slopes can be obtained and the basic properties of the evolution of a barchan dune can be described. q 2000 Elsevier Science B.V. All rights reserved.
منابع مشابه
مـدلسـازی بـرآورد حجـم تپـههـای بـرخـانی(مطالعه موردی: برخان-های منطقه چاهجام)
1. Introduction Among sedimentary systems that are rich and poor in terms of sediment load, a different organization of the sand dunes can be seen. Barchan dunes are one of the accumulative landforms of wind that are considered from poor sedimentary systems in desert environments. The dunes are the crescent shape, and have two horns at the end. Along the horns the prevailing wind direction...
متن کاملThe Shape of the Barchan Dunes in the Arkhangelsky
Sand dunes are beautiful sand patterns formed by the wind, and have been seen in many places on Mars. In particular barchan dunes, which have a crescent shape, propagate on solid ground under unidirectional winds and are very common on earth’s deserts and coasts, have been observed forming corridors on the floor of martian craters and also on the north pole. However, barchan dunes on Mars have ...
متن کاملOn the crescentic shape of barchan dune
Aeolian desert sand dunes birth from wind flow and sand bed interactions: depending on wind properties and sand availability, they can adopt several different shapes from huge motionless star dunes to small and fast mobile barchan dunes. These latter have a characteristic crescentic shape and form on hard ground with low sand supply under a monodirectional wind . Here, a 3d barchan model based ...
متن کاملStatistical Analysis of Sediment Diameter of West Lut Desert Barchan and the Study of their Type and Origin
Extended abstract 1- Introduction Granulometric analysis is a common tool used to understand and determine the origin of wind sands, and is applied in desertification studies; to realize such knowledge, the parameters of sand particles size as well as statistical analysis such as mean, standard deviation, kurtosis, skewness, etc. are used. One of the most common types of sand dunes formed...
متن کاملOn the crescentic shape of barchan dunes
Aeolian sand dunes originate from wind flow and sand bed interactions. According to wind properties and sand availability, they can adopt different shapes, ranging from huge motion-less star dunes to small and mobile barchan dunes. The latter are crescentic and emerge under a unidirectional wind, with a low sand supply. Here, a 3d model for barchan based on existing 2d model is proposed. After ...
متن کامل