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...

We apply a model for sand dunes to calculate formation of dunes on Mars under the present Martian atmospheric conditions. We find that different dune shapes as those imaged by Mars Global Surveyor could have been formed by the action of sand-moving winds occurring on today's Mars. Our calculations show, however, that Martian dunes could be only formed due to the higher efficiency of Martian win...

Seasonal periodicity of seed germination and its relationship to seasonal changes in temperature and soil moisture have been well studied in seeds of species with physiological dormancy. However, relatively little information is available on the role of these environmental factors in controlling germination of seeds with physical dormancy (PY). Our primary aim was to determine if seeds of the c...

Sand dunes are found in a wide variety of shapes in deserts and coasts, and also on the planet Mars. The basic mechanisms of dune formation could be incorporated into a continuum saltation model, which successfully reproduced the shape of the barchan dunes and has been also applied to calculate interaction of barchans in a field. We have recently extended our dune model to investigate other dun...

The trait-based approach shows that plant functional diversity strongly affects ecosystem properties. However, few empirical studies show the relationship between soil fungal diversity and plant functional diversity in natural ecosystems. We investigated soil fungal diversity along a restoration gradient of sandy grassland (mobile dune, semifixed dune, fixed dune, and grassland) in Horqin Sand ...

We apply a model for sand dunes to calculate formation of dunes on Mars under the present Martian atmospheric conditions. We find that different dune shapes as those imaged by Mars Global Surveyor could have been formed by the action of sand-moving winds occuring on today’s Mars. Our calculations show, however, that Martian dunes could be only formed due to the higher efficiency of Martian wind...

CA-AIV-4754 was investigated during the summer of 1997 as part of the City of La Quinta's Adams Street widening project. This well-stratified sand dune deposit was initially an encampment associated with the exploitation of fish during the last stand of ancient Lake Cahuilla. With the desiccation of the lake the site remained in use sporadically and exhibited a change in sUbsistence practices r...

Large areas of Iran are under the influence of wind erosion thus it is important that we recognize three zones ofremoval, transportation and deposition. The deposition zone is very important due to more damages and tangibleeffects. In this study we try to obtain a comprehensive idea to Persian desert with use of laboratory facilities, remotesensing, GIS and field surveying. We survey 28 ergs in...

Local adaptation may occur when selection for heritable traits differs from environment to environment and gene flow among environments is restricted. In this study, we used reciprocal transplants to explore both the existence and possible causes of local adaptation in the clonal plant Hydrocotyle bonariensis at high and low elevations of sand dunes on St. George Island, Florida. Individuals fo...