نتایج جستجو برای: sand dune
تعداد نتایج: 29993 فیلتر نتایج به سال:
An endeavor to feel the pulse of a coast devastated by a powerful oceanographic event is made. Results of field investigations along Tamil Nadu seaside revealed that the tsunami of December 2004 demolished dwellings within strips ranging from 6 to 132 m (average width, 41 m) from the dune, and flooded up to 862 m (average, 247 m) from the shore. The event damaged sand dunes, ripped dune vegetat...
sand dune habitats in desert regions have harsh conditions for plant establishment and survival. ammodendron persicum, an psamophyte shrub plant belongs to leguminosae family, which grows over the desert sand dunes of zirkohgaen, gezik and khash along east part of iran. recognizing the adaptive features of the plant species may help towards its conservation and introducing to other sand dune h...
Located just north of the Arctic Circle, the Great Kobuk Sand Dunes (GKSD) are an inland dune field that is closely surrounded by boreal forest. The history of the GKSD tells us about changes in aridity, a climatic parameter whose history is poorly understood at high latitudes. Vegetated dunes in several states of geomorphic preservation surround the active dune field today, evidencing a comple...
We present measurements of wind velocity and sand flux performed on the windward side of a large barchan dune in Jericoacoara, northeastern Brazil. From the measured profile, we calculate the air shear stress using an analytical approximation and treat the problem of flow separation by an heuristic model. We find that the results from this approach agree well with our field data. Moreover, usin...
the effect of soil and phanerogam characteristics on bryophytes composition, richness, abundance and functional groups were investigated in order to understand the factors responsible for bryophytes distribution patterns. three different sand dunes were selected: untouched, artificial sod-covered and planted by ammophila. along 10 transects perpendicular to the shore, a total of 142 permanent r...
Barchan dunes emerge as a collective phenomena involving the generation of thousands of them in so called barchan dune fields. By measuring the size and position of dunes in Moroccan barchan dune fields, we find that these dunes tend to distribute uniformly in space and follow an unique size distribution function. We introduce an analytical mean-field approach to show that this empirical size d...
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...
Sand dunes are often covered by vegetation and biogenic crusts. Despite their significant role in dune stabilization, biogenic crusts have rarely been considered in model studies of dune dynamics. Using a simple model, we study the existence and stability ranges of different dune-cover states along gradients of rainfall and wind power. Two ranges of alternative stable states are identified: fix...
The sand-binding plant Ammophila arenaria (L.) Link, commonly known as marram grass, has many characteristics which contribute to its usefulness in the initial stages of stabilisation of coastal sand and account for its selection for this purpose in most temperate countries. Research and experience in New Zealand have demonstrated the success of revegetation programmes based on its use in a pla...
Over the Tibetan Plateau and adjacent regions, numerous (14)C-based lake records revealed a ubiquitous wet climatic period during 40-25 ka (late MIS 3), which is in contradiction with the global pattern of generally cold and dry climates. This paper focuses on OSL dating results of a large set of sand dunes and alluvial sediments (50 OSL ages) from the Qinwangchuan (QWC) Basin at the northeast ...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید