Saharo-Arabian deserts includes large expanses of sand dunes called ergs. These dunes are formed and constantly reshaped by prevailing winds. Previous study shows that Saharan ergs exhibit significant backscatter (σ) azimuth angle (φ) modulation. The phases of the modeled σ versus φ harmonics over the ergs are correlated to the orientation of the dune fields. Most of the vertical variation in e...

Booming dunes” are large desert sand dunes that make a loud droning or humming noise during an avalanching of sand. The phenomenon has been observed for censturies, yet it remains largely unexplained. This note demonstrates that the booming frequency does not scale with the size of the particle or with the shearing speed of the avalanching sand. Instead, the dune may act as a waveguide with a f...

The mycorrhizal status of dune plants from the island of Hawaii was investigated. All plants, including Batis maritima, Cocos nucifer, Ipomoea brasiliensis, Pennisetum setaceum , Prosopis pallida, Scaevola taccada, and Sporobolus sp., had vesicular urbuscular mycorrhizae (VAM) . Levels of colonization by VAM fungi ranged from less than 10% to 100% of the root length and were highest in Ipomoea ...

Almost fifty years of investigations of barchan dunes morphology and dynamics is reviewed, with emphasis on the physical understanding of these objects. The characteristics measured on the field (shape, size, velocity) and the physical problems they rise are presented. Then, we review the dynamical mechanisms explaining the formation and the propagation of dunes. In particular a complete and or...

Vegetation is the most common and most reliable stabilizer of loose soil or sand. This ancient technique is for the first time cast into a set of equations of motion describing the competition between aeolian sand transport and vegetation growth. Our set of equations is then applied to study quantitatively the transition between barchans and parabolic dunes driven by the dimensionless fixation ...

Introduction: Recent observations by the Cassini spacecraft show widespread regions of longitudinal dunes on Saturn’s moon Titan [1]. The exact composition of the dunes is not known, but its radar and infrared return suggest an organic component [2]. Given the broad extent of the dunes (they cover 40% of Titan’s equatorial areas), they constitute an important portion of Titan’s overall organic ...

This paper proposes a method for modeling and rendering realistic desert scenes. A desert terrain includes sand dunes and wind ripples. We use two types of scale models to form them. We render the dunes with the wind-ripples by bump-mapping using LODs (Levels of Detail).

sand dunes mobility is one of the serious problems in arid regions. since wind regime is one of the important factors in sand dunes formation, its frequency, direction and magnitude can be effective. amount of wind energy and its directional variability (wind regime) have significant control on the morphology and maintenance of aeolian landforms. by recognizing of morphometric and morphodynamic...