Understanding the unusual radar scattering characteristics of sand dunes is necessary in the analysis of radar images of aeolian landscapes of the earth and of other planets. In this paper we report on airborne radar scatterometer data of sand dunes, acquired at multiple frequencies and polarizations. Radar backscatter from sand dunes is very sensitive to the imaging geometry. At small incidenc...

Barchan dunes were found to transform into parabolic dunes and vice versa when the amount of vegetation on and around them changes. This work presents the first numerical simulation of this effect. We propose a continuum model for the density of vegetation. An established sand transport model is used for simulating the evolution of the dunes.

The physical development of cities is always faced with natural barriers. The physical development of the city of Zabol, located in the Sistan plain, is threatened specifically with the development of sand dunes. For this reason, the region’s drought conditions were investigated and the standardized precipitation index was calculated. The results showed that with the drying of Hamoon Lake, the ...

introduction coastal sand dunes are  important morphological forms in caspian coastal regions. these dunes are formed and developed under the influence of sediment influx, climate, impact of wind, waves, currents. these are parallel to the coastal characterisitics with enough space for expansion. the whole collection of these parameters are available in many coastal areas of the caspian sea , b...

Saharo-Arabian deserts includes large expanses of sand dunes called ergs. These dunes are formed and constantly reshaped by prevailing winds. In this paper, we use backscatter (σo) measurements observed at various azimuth angles from SeaWinds scatterometer (QSCAT) and ERS scatterometer (ESCAT) to determine the σo azimuthal modulation over the sand dunes. A second order harmonic equation is used...

the kashan erg is one of the most important sand dune complexes in iran. being affected by wind erosion, theerg's borderlands face numerous problems as a result of sand movement. to evaluate the risk of sands moving intoresidential areas near the kashan erg, anemometry data from synoptic stations located in kashan, ardestan, meimeh,naeen, and qom were collected and analyzed to calculate the san...

Whether the winds of the present Mars are shaping the variety of dune forms observed on the Martian surface has remained an open question that challenged planetary scientists for decades. In order to elucidate this issue, we have studied sand transport and dune formation from two different points of view. The first approach consists of solving the equations of aeolian transport at the level of ...

Transverse dunes appear in regions of mainly unidirectional wind and high sand availability. A dune model is extended to two dimensional calculation of the shear stress. It is applied to simulate dynamics and morphology of transverse dunes which seem to reach lateral invariance and do not stop growing. Hence, simulations of two dimensional dune fields have been performed. Characteristic laws we...

Introduction: Exotic sand dunes on Mars have been known since 1972 when NASA's Mariner 9 spacecraft transmitted images of their interesting shapes. This is a common feature across the surface of Mars. Despite three decades of studying these features [e.g., 1-16], many questions remain regarding their composition, sources of sediment, morphology, age , origins, and dynamics under present and pas...