A stochastic model for initial movement of sand grains by wind
Aeolian features ; Aeolian transport ; Model ; Stochastic model ; Threshold ; Wind ; Wind speed
A stochastic model for entrainment of sand grains by wind is presented through analysis of the forces exerted on a single spherical grain, coupled with fluctuations of wind velocity and the change in grain position on the surface, in order
to understand the probability of initial movement of sand grains by wind.
Geographical position of Slovenia is the main reason that applicable winds are quite infrequent, therefore the knowledge about specific local winds is of a great significance. The research objective was to determine and evaluate conditions
for the development of amplified morning thermic wind in the gulf in front of Barcola village near Trieste, analyzing the general weather conditions, local wind and air temperature conditions and the influence of coastal relief. The article shows that beside air
temperature difference between coastal region and the Karst plateau, steep coastal relief with explicit valleys and narrows, the final wind parameters are influenced also by general air-mass movement in broader the Karst plateau. The comparison of actual wind
conditions with wind forecasts of meteorological model ALADIN returns the outlook of criteria for reliable forecasts of amplified morning thermic wind - (IKR)
Validation of WEQ, RWEQ and WEPS wind erosion for different arable land management systems in the Argentinean Pampas
Agricultural practice ; Argentina ; La Pampa ; Model ; Pampa ; Semi-arid area ; Soil erosion ; Wind ; Wind erosion
As an effort to apply wind erosion models, the AA. compared field wind erosion measurements carried out during 4 years in a bare soil reference plot and during 3 years in the same soil with different tillage conditions. Wind erosion was predicted
with : 1) subroutines for single storm event versions of the wind erosion prediction system (WEPS) and the revised wind erosion equation (RWEQ), for which the climatic data of each single storm were used, and 2) the wind erosion equation (WEQ) for full
as a reliable prediction model for long-term predictions of wind erosion in the semi-arid pampas, even when run with limited available climatic data for this region.
The paper concludes there is a future for wind energy, world-wide and also in Germany, but preferably in places where there is a maximum of efficiency and a minimum of negative side effects. The article deals with wind energy, energy discussion, CO2
Baltic Sea ; Coastal environment ; Energy ; Poland ; Pomerania ; Wind energy
The paper presents the environmental, landscape, social, economical and technical conditions for development of wind energy on the South Baltic Coastland and the Baltic Sea near the Pomeranian voivodeship. The analysis suggests that marine locations
have fivefold larger potential for wind energy development than land locations - due to higher wind speed and more areas appropriate for wind energy plant localization. - (BJ)
Biogeography ; Ecotone ; Forest ; Linear forest ; Mountain ; Self-organizing behaviour ; Subalpine area ; Wind
Roughly linear forest patches are common in subalpine environments, including hedges, ribbon forest, and Shimagare or wave regenerated forests (waves). The influence of wind is common among these patterns, but the role of positive feedback, the most
important component of self-organization in biological systems varies. Hedges and waves can develop endogenously with a constant wind, and so can be considered self-organizing. Most ribbon forests seem to be dominated by exogenous forces.
Coastal dynamics ; Coastal environment ; Coastal erosion ; Mass movement ; Sea level ; United Kingdom ; Wales ; Wave ; Wind
as causes. The time-frame of significant erosion was between 1995 and 1997 and forcing agents (extreme sea level and wind direction) and shoreline indicators (mean beach level and Mean High Water) were analysed in order to assess change. Relationships showed
correlation between forcing agents (extreme sea level and wind direction) and shoreline indicators. It was concluded that the critical erosion of Penarth beach between 1995 and 1997 was caused by increased wave attack generated by unique significant changes
Predicting the effect of tilling practices on wind erosion activity : application of the Wind Erosion Prediction System in a sand drift area in The Netherlands
Aeolian features ; Agricultural practice ; Experimentation ; Forecast ; Model ; Netherlands (The) ; Simulation ; Wind erosion
-month experiment at Kootwijkerzand. The effectiveness of the techniques to reactivate the aeolian processes was measured by investigating their effect on the horizontal sediment flux. Furthermore, the Wind Erosion Prediction System was used to simulate
Effect of grazing on wind driven carbon and nitrogen ratios in the grasslands of Inner Mongolia
Aeolian features ; Aeolian transport ; Arid area ; China ; Dust storm ; Grassland ; Impact ; Inner Mongolia ; Over-grazing ; Semi-arid area ; Vegetation ; Wind erosion
Wind erosion and dust storms are common phenomena in the semi-arid Xilingele grassland (Inner Mongolia) and contribute considerably to matter balances. Based on wind erosion measurements in spring 2005 and 2006 the organic carbon and total nitrogen
contents of dust were analyzed to determine the contribution of wind erosion processes on C- and N-ratios to the grasslands. The great range of dust emission and deposition at the different grazing intensities underlines the sensibility of the grassland
In this study the AA. aimed at quantifying the effects of vegetation cover and topography on surface roughness over a stabilizing dune field on the southern coast of Israel. 46 wind measurements were made at various distances from the coastline
, ranging from 10 to 2800 m, and Zo values were calculated from the wind measurements based on the ratio between the wind gust and the average wind speed. The AA. estimated vegetation cover using the soil adjusted vegetation index (SAVI) from Landsat
these variables the AA. were able to create a map of estimated Zo values. Such maps provide a better understanding of the spatial variability in both wind speed and sand movement over coastal dune areas.
A three-dimensional analysis on lift-off velocities of sand grains in wind-blown sand flux
Aeolian features ; Aeolian transport ; China ; Comparative study ; Gansu ; Model ; Sand ; Wind
This paper focuses on a key problem in wind-blown sand transport research, the lift-off velocities of sand grains. A three-dimensional grain-bed collision model comprising an impact sand grain, a creeping sand grain and a sustaining grain
Aeolian features ; Aeolian transport ; Arid area ; China ; Desert ; Dust ; Experimentation ; Gansu ; Turbulence ; Wind speed
The flow of glass dust particles in air was investigated experimentally over a flat bed in a wind tunnel. Particle concentrations were measured by light scattering diffusion (LSD) and digital image processing. It was verified that saltation
. Their origin could only be wind or waves driven. Although many chevrons resemble narrow parabolic coastal dunes, a young aeolian genesis can be excluded where orientation contradicts main wind direction, or where no beach or sand deposit exists. Where storm