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Electrification of wind-blown sand on Mars and its implications for atmospheric chemistry  [PDF]
J. F. Kok,N. O. Renno
Physics , 2009, DOI: 10.1029/2008GL036691
Abstract: Wind-blown sand, or 'saltation,' creates sand dunes, erodes geological features, and could be a significant source of dust aerosols on Mars. Moreover, the electrification of sand and dust in saltation, dust storms, and dust devils could produce electric discharges and affect atmospheric chemistry. We present the first calculations of electric fields in martian saltation, using a numerical model of saltation that includes sand electrification, plasma physics, and the adsorption of ions and electrons onto particulates. Our results indicate that electric discharges do not occur in martian saltation. Moreover, we find that the production of hydrogen peroxide and the dissociation of methane by electric fields are less significant than previously thought. Both these species are highly relevant to studies of past and present life on Mars.
Electrostatics in wind-blown sand  [PDF]
Jasper F. Kok,Nilton O. Renno
Physics , 2007, DOI: 10.1103/PhysRevLett.100.014501
Abstract: Wind-blown sand, or "saltation," is an important geological process, and the primary source of atmospheric dust aerosols. Significant discrepancies exist between classical saltation theory and measurements. We show here that these discrepancies can be resolved by the inclusion of sand electrification in a physically based saltation model. Indeed, we find that electric forces enhance the concentration of saltating particles and cause them to travel closer to the surface, in agreement with measurements. Our results thus indicate that sand electrification plays an important role in saltation.
A General Model Predicting the Streamwise Sand Transport Rate with Saltating Sand Charged

HU Wen-wen,WANG Ping,

中国沙漠 , 2011,
Abstract: The streamwise sand transport rate,also known as wind-blown sand transport rate,is a vital parameter in wind-blown sand flux.Based on numerical simulation of the wind-blown sand saltation with the sand electrification,the streamwise sand transport rates are calculated in this paper.By analyzing the results,a predicting model for wind-blown sand transport rate is established,which is a function of particle diameter,wind velocity and the electrical charge.The predicted mass transport rates agree well with tho...
An electrostatic dynamic model for wind-blown sand systems

Lu Lu-Yi,Gu Zhao-Lin,Luo Xi-Lian,Lei Kang-Bin,

物理学报 , 2008,
Abstract: An electrostatic dynamic model for wind-blown sand systems of dust devils or sand-dust storms was developed based on the electrochemistry of water molecular film on the surface of particles, in which water is ionized as H3O+/HO- and their concentration vary with temperature. The mobility of H3O+ from high concentration regime to low concentration regime is greater than that of HO-. The interaction of particles result in the change of particle kinetic energy and the particle surface temperature. The simulation of a three-sized particle system with diameters of 0.1, 0.2, and 0.4mm and particle numbers of 750, 100 and 50, respectively, shows that the small particles are charged negatively while the large particles are charged positively, which reasonably explains the electrostatic mechanism of dust devils and sand-dust storms. It was also found that the electrification is relevant to the humidity of granule system, which explains Guardiola's experiments. Coupled with gas-particle two-phase flow model, this electrostatic dynamic model will improve the accuracy of numerical simulation of the wind-blown sand system.
The physics of wind-blown sand and dust  [PDF]
Jasper F. Kok,Eric J. R. Parteli,Timothy I. Michaels,Diana Bou Karam
Physics , 2012, DOI: 10.1088/0034-4885/75/10/106901
Abstract: The transport of sand and dust by wind is a potent erosional force, creates sand dunes and ripples, and loads the atmosphere with suspended dust aerosols. This article presents an extensive review of the physics of wind-blown sand and dust on Earth and Mars. Specifically, we review the physics of aeolian saltation, the formation and development of sand dunes and ripples, the physics of dust aerosol emission, the weather phenomena that trigger dust storms, and the lifting of dust by dust devils and other small-scale vortices. We also discuss the physics of wind-blown sand and dune formation on Venus and Titan.
Influence of the Thermal Diffusion of the Sand Bed on the Evolutive Process of the Wind Blown Sand Flux

Lin Haixiao,Yue Gaowei,

气候与环境研究 , 2010,
Abstract: A theoretical model with considering the thermal diffusion (TD) from the sand-bed is used to study the effect of the TD during the evolution of the wind-blown sand flux. And in the wind-blown sand flux the coupling interaction is taken into consideration among wind speeds in the vertical and horizontal directions, and the sand movement. The numerical results show that it is quite obvious for the evolutive process of the sand-driving wind affected by the TD of the bed. When the wind-blown sand flux reaches a...
Natural factors influencing blown sand hazards in Beijing
Lianyou Liu,Peijun Shi,Xia Hu,Tianke Liu,Lanlan Guo,Xiaoxiao Zhang,Yan Tang,Yanli Lv,Bingyan Sun,Guoming Zhang,Xiaoning Zhang,Weiqiang Zhang,Yanyan Yang,Jingpu Wang,Yiying Xiong
International Journal of Disaster Risk Science , 2011, DOI: 10.1007/s13753-011-0008-5
Abstract: In this article, natural factors in the farming-pastoral ecotone that might have influenced the blown sand hazards in Beijing in 2000 are analyzed. In the farming-pastoral ecotone, blown sand activities took place primarily in springtime, during which 39.8 percent of the annual frequency of erosive winds above threshold occurred. The prevailing directions of the erosive winds were NNW, NW, NWW, and N, with frequencies of 47, 20, 13, and 9 percent respectively. Sand entrainment and dust emission are influenced by erosive wind frequency, soil moisture, and land use and cover change. Favorable wind characteristics and a lasting drought in 1999 and 2000 may have produced ideal conditions for land surface desiccation, vegetation degradation, and land surface mobility and the occurrence of intense sand- and dust storms in Beijing.
A transport-rate model of wind-blown sand

ZhiBao Dong,

寒旱区科学 , 2009,
Abstract: Sand transport by wind plays an important role in environmental problems. Formulating the sand-transport rate model has been of continuing significance, because the majority of the existing models relate sand-transport rate to the wind-shear velocity. However, the wind-shear velocity readapted to blown sand is difficult to determine from the measured wind profiles when sand movement occurs, especially at high wind velocity. Detailed wind tunnel tests were carried out to reformulate the sand-transport rate model, followed by attempts to relate sand-transport rate to parameters of wind velocity, threshold shear-velocity, and grain size. Finally, we validated the model based on the data from field observations.

Chen Guangting,He Daliang,Song Jinxi,Guan Youzhi,

地理研究 , 1988,
Abstract: In recent years, argument about wind-drift sand of Beijing has continued arising This paper presented some understandings for wind-drift sand problems of Beijing based on the field investigaton. 1) In accordance with geoche-micaJ analysis of heavy minerals and microelements in the sand caused by various reasons, and comparison with near by deserts and sandy lands, it is confirmed that wind-drift sand materials in Beijing are river sediments of the local region, which are blown off and then accumulated, and dust storm and particles come mainly from the areas where prevailing wind occurs and passes through. 2) According to the data observed in meteorological stations in various counties of Beijing for a long time, wind-drift sand of Beijing is divided into five types, i.e. blowing sand; blowing sand-suspended dust,suspended dust by strong wind; suspended dust and sand storm. Regional distributive law of different wind-drift sand is presented too in this paper. Meanwhile it points out that differances of geomorphic position and surface sediment type of stations are the basic causes of the formation of different sand types 3 ) Several fluctuations of sand drifting days occur with increasing or reducing of strong wind days and the changes in phenomenon of sand storm, suspended dust and biowing sand also take place, but the general trend of sand drifting days are gradually reducing. Taking the data of Beijing city as an example, the average annual sand drifting days reduce from 78 days in the early 1950s to 19.3 days in the eariy 1980s. It indicates that increasing green areas and establishing and perfecting anti-wind system in Beijing in planned way are the primary measures to cotrol wind-drift sand
Preliminary Study on Blown Sand Disaster along the Gobi Highway

YOU Quan-gang,XUE Xian,WANG Tao,ZHAO Fa-zhang,ZHANG Wei-min,LIU Guang-xiu,ZU Rui-ping,HAN Bang-shuai,MAN Fu-cheng,

中国沙漠 , 2011,
Abstract: The Anxi-Jiayuguan highway is set up in the western Gansu Corridor with Gobi as the main geomorphology.In order to predict and prevent blown-sand hazards to the highway,the authors in this paper conducted field investigation,wind field calculation and blown wind observation along the highway in study area.It is difficult for sand particles to be eroded in Gobi area due to high roughness of land surface,but degraded nebkhas that distribute in the study area are the direct sand sources.The dominant sand-blowi...
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