نتایج جستجو برای: cross sand dunes
تعداد نتایج: 518686 فیلتر نتایج به سال:
Spring-summer winds from the south move moist air from the Gulf of Mexico to the Great Plains. Rainfall in the growing season sustains prairie grasses that keep large dunes in the Nebraska Sand Hills immobile. Longitudinal dunes built during the Medieval Warm Period (800 to 1000 years before the present) record the last major period of sand mobility. These dunes are oriented NW-SE and are compo...
We model formation and evolution of transverse dune fields. In the model, only the cross section of the dune is simulated. The only physical variable of relevance is the dune height, from which the dune width and velocity are determined, as well as phenomenological rules for interaction between two dunes of different heights. We find that dune fields with no sand on the ground between dunes are...
Calligonum mongolicum is a successful pioneer shrub to combat desertification, which is widely used for vegetation restoration in the desert regions of northwest China. In order to reveal the limitations to natural regeneration of C. mongolicum by asexual and sexual reproduction, following the process of sand dune stabilization, we assessed clonal shoots, seedling emergence, soil seed bank dens...
Golan Bel and Yosef Ashkenazy Department of Environmental Physics, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel (Dated: May 11, 2014) Abstract Psammophilous plants are special plants that flourish in sand moving environments. There are two main mechanisms by which the wind affects these plants: (i) sand drift exposes roots and cov...
kashan erg is one of the most important sand dunes complexes in iran. it is included the most important various type of sand dunes in iran. this study was performed to compare the granulometry of aeolian sediments in different sand dunes and also from plinth to crest of transverse dunes that located in kashan erg’s north. in order to determining different statistical variables, aeolian sediment...
Grain size is one of the most obvious characteristics in many studies of Aeolian erosion, Ergs, moving of sand dune, etc. Comparison of Grain size and morphoscopy between new and old sand dunes in an Erg, help us to identify the sources sand and control reactivity sand dunes. This study, as first step, by aerial photography and satellite imagery attempting to identify areas were sedimented. The...
Endemic species are those that exist at only one location or area on Earth. They tend to be more numerous in habitats that are distinctly different from the surrounding areas. The Great Sand Dunes harbor at least seven endemic species of insects. Many of the insects here are ‘sand obligates’, meaning that they are adapted uniquely for sandy habitats. Currently, just over 1,000 different kinds o...
Wind regime and sand grain size are two of the factors that determine the morphology and dynamics of sand dunes in desert areas. Regarding the importance of wind effects on sand dunes especially in Iran, in this study, Khartooran Erg was analyzed to determine wind direction and to detect sand source sites. Khartooran Erg is located on eastern north of Iran and lies in Khorasan Razavi and Semnan...
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...
wind regime and sand grain size are two of the factors that determine the morphology and dynamics of sand dunes in desert areas. regarding the importance of wind effects on sand dunes especially in iran, in this study, khartooran erg was analyzed to determine wind direction and to detect sand source sites. khartooran erg is located on eastern north of iran and lies in khorasan razavi and semnan...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید