A5080230806- Aeolian processes and effects
- Geology and Paleoclimatology Research
- Soil erosion and sediment transport
- Geological formations and processes
- Marine and environmental studies
- Biocrusts and Microbial Ecology
- Planetary Science and Exploration
- Tree Root and Stability Studies
- Soil and Environmental Studies
- Fire effects on ecosystems
- Air Quality and Health Impacts
- Archaeology and ancient environmental studies
- Ecology and Vegetation Dynamics Studies
- Geography and Environmental Studies
- Land Use and Ecosystem Services
- Particle Dynamics in Fluid Flows
- Geological Studies and Exploration
- Maritime and Coastal Archaeology
- Archaeology and Historical Studies
- Ancient and Medieval Archaeology Studies
- Rangeland and Wildlife Management
- Hydrology and Sediment Transport Processes
- Scientific Research and Discoveries
- Environmental and biological studies
- Space Exploration and Technology
Ben-Gurion University of the Negev
2008-2020
Hebrew University of Jerusalem
1983
ABSTRACT Although contemporary dust storms are frequent in arid and semi‐arid areas, desert loess deposits poorly developed. Much of the World's occurs mid‐latitude areas which experienced glaciation during Pleistocene. Ocean core evidence indicates that transport from sub‐tropical deserts increased cold stages Pleistocene, but formed only on certain margins, for reasons have not been fully explained. This paper re‐examines mechanisms deposition, circumstances leading to accumulation thick...
ABSTRACT Field measurements were made on a longitudinal dune in the Sinai Desert order to understand its morphology and dynamics. The field contradicted wind structure indicated by helicoidal flow theory. Rather, it was found that winds coming from two basically different directions at times striking obliquely responsible for sand transport erosion or deposition along lee flank. essence of this mechanism is deflection airflow flank direction parallel crest line. occurrence depends upon angle...
The Mediterranean coastal dunes of Israel underwent a land-use change during the second half 20th century. Due to intense agricultural and pastoral activity, were stripped natural vegetation until end first barchan transverse shaped by strong southwesterly winter winds. A decrease in human activity century brought about renewal on dune crest—the only area with neither erosion nor deposition. establishment crest changes dynamics these dunes, so that not all sand eroded from windward side is...
Viking Orbiter 2 images of the north polar region reveal an enormous sand sea (erg) covering area >5×10 5 km around perennial ice cap. All dunes are either transverse or barchan. The various dune morphologies and modification primary types reflect a wind regime having more than one direction. In summer, two major directions prevail: (1) off‐pole winds that become easterly due to coriolis forces (2) on‐pole westerly. During winter and/or spring, only exist. Strong (>75 m/s) required for...
We provide several examples for the coexistence of active and fixed sand dunes under similar climatic conditions, namely, with respect to wind power precipitation rate. A model is developed dune vegetation cover that includes power, rate, anthropogenic effects, such as grazing wood gathering. The reproduces observed dune's bistability shows intense human pressure prolonged droughts may turn active. Moreover, reactivation process almost irreversible, a will become only action very strong...
Sand dunes can be active (mobile) or stable, mainly as a function of vegetation cover and wind power. However, there exists yet unexplained evidence for the coexistence bare mobile vegetated stabilized under same climatic conditions. We propose model dune driven by power that exhibits bistabilty hysteresis with respect to For intermediate power, coexist, whereas low (or high) they fixed mobile). Climatic change human intervention turn into stable ones vice versa; our predicts prolonged...
Abstract The effect of biogenic crust on imagery acquired by spaceborne sensors is demonstrated. consists mostly microphytes such as cyanobacteria. macrophytes (higher vegetation) the sand dunes are sparse and have a relatively low spectra! reflectance response. However, since considerable ponton ground covered this crust, (which has different spectral from that mobile sands), sharp brightness contrast created between two areas. It can be concluded well-known Sinai (Egypt) Negev (Israel),...
Most geomorphologists and geologists do not differentiate the various types of linear dune refer to them as one type mainly in terms linear, longitudinal or seif dunes. In recent morphodynamic genetic classifications dunes, all dunes are lumped under heading (Wasson Hyde, 1983; Hunter et al., 1983). This review, however, substantiates three different simple - lee seifs vegetated- each which has a shape mechanism formation elongation.
Abstract The coast of Ceará State in NE Brazil is covered by vast fields active and stabilized coastal sand dunes. Its tropical climate characterized two seasons, wet dry, with wind intensity determined the meridional shift Intertropical Convergence Zone. power negatively correlated precipitation, precipitation difference between sea surface temperatures Atlantic north south equator. We present a model suggesting that during Late Pleistocene mobility stability Sand dunes accumulated periods...
The study of dune morphology represents a valuable tool in the investigation planetary wind systems--the primary factor controlling shape is directionality. However, our understanding formation still limited to simplest situation unidirectional winds: There no model that solves equations sand transport under most common seasonally varying directions. Here we present calculation bimodal winds using extended account for more than one direction. Our calculations show dunes align longitudinally...