The effectiveness of Barchan morphometric parameters on its movement rate (Case study Chah Jam Erg)



  Abstract   Aeolian sand dunes originate from reciprocal interaction between wind flow and sand bed. Barchan dunes are one of the Aeolian compressive forms and are formed in areas that there is not enough sand to cover the entire surface and wind flow comes steadily from the same direction throughout the year. These features have been formed from quick sand. One of the most important of their characteristics is dynamic and lateral movements, that some parts of them are regarded as crisis and threatening focuses for urban and rural settlements, economic and military centers and communication ways. Totally, Barchan dunes move proportionally to the wind velocity and inversely proportionally to their height. Their movement rate is subject to wind velocity, three dimensional morphology and interaction between them. One of the most common of Aeolian features in south of Haj Ali Gholi playa are Barchan dunes. In this study, morphometric parameters of Barchan dunes and their annual movement rate (from 1387/1/10 to 1388/1/10) have been measured via pique. Using regression analysis method, type and intensity of relationship between movement rate and morphometric parameters have been investigated and models have been presented in order to estimate their movement rate. Using these models can assess annual movement rate of Bachan dunes in the field area easily. The obtained results show that relationships between movement rates and morphometric parameters consistent with simple linear, power and exponential relationships. The obtained relationships from relation study between movement rate and Barchan morphometric parameters represents a maximum significant exponential reverse relationships of movement rate with height parameter with determination index of 0.915 and standard error of estimation of 0.133. The recognition of morphometric parameters of barchan can act as an index in order to determine the condition of barchan system and also shed light on the its trends. Furthermore recognition and estimate of these parameters is a consequence from rate of threat and distribution and provide for environmental managers with the same, that their investigation determines different region from the view point of environmental management and prioritize them.