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Aeolian sediment transport over sandy gobi:Field studies in the Nanhu gobi along the Hami-Lop Nor Railway

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International Soil and Water Conservation Research 2023年第1期11卷 125-134页

作者： Tao Wang jianjun qu Lihai Tan Key Laboratory of Desert and Desertification Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou730000China Dunhuang Gobi and Desert Ecology and Environment Research Station Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesDunhuang736200China Research Station of Gobi Desert Ecology and Environment in Dunhuang of Gansu Province Dunhuang736200China Breeding Basefor State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China Ningxia UniversityYinchuan750021China

Wind-blown sand over sandy gobi with an abundant sediment supply can cause severe sand ***,compared with the study of aeolian transport over gravel gobi with a limited sediment supply,less attention has been devoted to sandy gobi,and thus,our understanding of wind-blown sand movement on sandy gobi is still ***,we report the results of observations of three transport events on a sandy gobi along the Hami-Lop Nor Railway based on high-frequency saltation particle count and horizontal sediment flux measurements coupled with instantaneous wind velocity *** results reveal that,unlike the notably intermittent aeolian saltation over gravel gobi,continuous transport occurred on the sandy *** mean saltation layer height was 0.23±0.07 m,and it was positively related to both the grain size of surface particles and the wind velocity regardless of the gobi *** sediment transport rates could be expressed as the power function Q=ap/g[u^(*)(u^(*2)-u^(*)t^(2))]b,and the scaling parameter(b)reached to 2.5,which is much larger than that of other gobi areas(b=1).Our findings suggest that the wind-blown sand over sandy gobi is much more severe than that over gravel gobi,and the Nanhu sandy gobi is the major sand source for sand hazards of the Hami-Lop Nor ***-fixation measures such as checkerboard sand barriers with enhanced checkerboard size and barrier height should be the main subject of sand control systems for the Hami-Lop Nor Railway in sandy gobi.

关键词： Sandy gobi Saltation threshold salcation layer height Sediment transport rates Wind-blown sand control

Experimental definition and its significance on the minimum safe distance of blown sand between the proposed Qinghai-Tibet Expressway and the existing Qinghai-Tibet Railway

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Science China(Technological Sciences) 2020年第12期63卷 2664-2676页

作者： XIE ShengBo qu jianjun HAN QingJie PANG YingJun Key Laboratory of Desert and Desertification Dunhuang Gobi and Desert Research StationNorthwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China Institute of Desertification Studies Chinese Academy of ForestryBeijing 100091China

The Qinghai-Tibet Expressway is a major strategic project planned by China that will be built along the Qinghai-Tibet Engineering Corridor. At present,important traffic line projects,such as the Qinghai-Tibet Railway,have been built within this narrow corridor,particularly at the blown sand sections. How to ensure that the wind speed and its flow field between the new expressway and existing railway subgrades are not affected by each other is a priority to prevent breaking the dynamic balance of the blown sand movement of the existing subgrade,thereby avoiding aggravating or inducing new blown sand hazards and ensure the safe operation of the existing Qinghai-Tibet Railway. Therefore,defining the minimum distance of the wind speed and its flow field,which are not affected by each other,between the subgrades become a scientific problem that should be solved immediately to implement the construction of the Qinghai-Tibet Expressway. For this purpose,the minimum safe distance between the subgrades of the Qinghai-Tibet Expressway and Qinghai-Tibet Railway was investigated from the perspective of blown sand by making subgrade models for conducting wind tunnel experiments and combining the observation data of the local field. Results indicated that the minimum safe distance between the two subgrades is 45–50 times the subgrade height when the Qinghai-Tibet Expressway is located at the downwind direction of the Qinghai-Tibet Railway,and 50 times the subgrade height when the former is located at the upwind direction of the latter. These results have guiding significance for the route selection,survey,and design of the Qinghai-Tibet Expressway at the blown sand sections and for the traffic line projects in other similar sandy regions.

关键词： Qinghai-Tibet Expressway Qinghai-Tibet Railway wind speed wind flow field safety distance

Microclimate and CO_2 fluxes on continuous fine days in the Xihu desert wetland,China

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Journal of Arid Land 2015年第3期7卷 318-327页

作者： QianQian GOU jianjun qu ZhiWen HAN Key Laboratory of Desert and Desertification Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of Sciences Dunhuang Gobi and Desert Ecology and Environment Research Station Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of Sciences University of Chinese Academy of Sciences

The Xihu desert wetland is located in an extremely arid area in Dunhuang,Gansu province of Northwest *** area is home to an unusual geographic and ecological environment that is considered unique,both in China and the *** is not only related to topography,but is also affected by the physical properties of underlying ground *** and CO2 flux have different characteristics under different underlying surface ***,until now,few studies have investigated the microclimate characteristics and CO2 flux in this *** eddy covariance technique（ECT） is a widely used and effective method for studying such factors in different *** on data from continuous fine days obtained in the Dunhuang Xihu desert wetland between September 2012 and September 2013,this paper discussed and compared the characteristics of daily microclimate variations and CO2 fluxes between the two *** from both years showed that there was a level of turbulent mixing and updraft in the area,and that the turbulent momentum flux was controlled by wind shear under good weather *** horizontal wind velocity,friction wind velocity and vertical wind velocity were commendably consistent with each *** temperature in the surface layer followed an initial decreasing trend,followed by an increasing then decreasing trend under similar net radiation *** changes in air temperature,the soil temperature in the surface layer follows a more obvious sinusoidal fluctuation than that in the *** of ground surface radiation during the two study periods showed typical diurnal *** maximum diurnal absorption of CO2 occurred at around 11：00（Beijing time） in the Xihu desert wetland,and the concentrations of CO2 in both periods gradually decreased with *** area was therefore considered to act as a carbon sink during the two observation periods.

关键词： eddy covariance microclimate characteristics CO2 flux extremely arid region desert wetland Dunhuang

Influence of Golmud-Lhasa Section of Qinghai-Tibet Railway on Blown Sand Transport

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Chinese Geographical Science 2015年第1期25卷 39-50页

作者： XIAO Jianhua YAO Zhengyi qu jianjun Key Laboratory of Desert and Desertification Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Dunhuang Gobi and Desert Ecology and Environment Research Station Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Gansu Center for Sand Hazard Reduction Engineering and Technology

The Qinghai-Tibet Railway(QTR) passes through 281 km of sandy land, 11.07 km of which causes serious sand damage to the railway and thus, the control of blown sand is important for the safe operation of the railway. Construction of the railway and sand prevention system greatly changed the blown sand transport of the primary surface. Effective and feasible sand-control measures include stone checkerboard barriers(SCBs), sand fences(SFs), and gravel coverings. This study simulated the embankments, SCBs and SFs of the QTR in a wind tunnel, and analyzed their respective wind profile, sand deposition, and sand-blocking rate(SBR) in conjunction with field data, aiming at studying the influence of Golmud-Lhasa section of the QTR and sand prevention system on blown sand transport. The results of wind tunnel experiments showed that wind speed increased by 67.7%–77.3% at the upwind shoulder of the embankment and decreased by 50.0%–83.3% at upwind foot of embankment. Wind speed decreased by 50.0%–100.0% after passing through the first SF, and 72.2%–100.0% after the first row of stones within the first SCB grid. In the experiment of sand deposition, the higher the wind speed, the lower the SBR of SCB and SF. From field investigation, the amount of sand blocked by the four SFs decreased exponentially and its SBR was about 50.0%. By contrast, SCB could only block lower amounts of sand, but had a higher SBR(96.7%) than SF. Although, results show that SFs and SCBs along the Golmud-Lhasa section of the QTR provide an obvious sand blocking effect, they lead to the deposition of a large amount of sand, which forms artificial dunes and becomes a new source of sand damage.

关键词： Qinghai-Tibet Railway(QTR) wind profile blown sand transport sand damage wind tunnel

Large scale sand saltation over hard surface:a controlled experiment in still air

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Journal of Arid Land 2021年第6期13卷 599-611页

作者： LIU Benli WANG Zhaoyun NIU Baicheng qu jianjun Key Laboratory of Desert and Desertification Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China Research Station of Gobi Desert Ecology and Environment in Dunhuang of Gansu Province Lanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China Qinghai Normal University Xining 810004China

Saltation is the major particle movement type in wind erosion *** sand grains can rebound up to tens of times larger in length and height over hard surface(such as gravel surface)than over loose sand *** usually have different faces,causing distinct response of the impacting grains,but the effects of the grain and gravel-surface contact angle on grain rebound are not yet well *** performed full-range controlled experiments of grain saltation using different contact angles,grain sizes and impact speeds in still air,to show that contact angle increases the height of representative saltation path but decreases particle travel *** results were compared with outputs from the COMprehensive numerical model of SALTation(COMSALT).Large saltation height of 4.8 m and length of 9.0 m were *** maximum and representative saltation height over the gravel surface were found to be about 4.9 times and 12.8 times those over the loose sandy surface,*** maximum saltation length may be reduced by 58%and the representative saltation height may be increased by 77%as contact angle increases from 20°to 40°.We further showed that the collision inertia contributes 60%of the saltation length,and wind contributes to the other 40%.These quantitative findings have important implications for modeling saltation trajectory over gravel surface.

关键词： sand saltation trajectory gravel surface contact angle full-scale experiment

Succession of soil bacterial and fungal communities of Caragana korshinskii plantation in a typical agro-pastoral ecotone in northern China over a 50-a period

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Journal of Arid Land 2021年第10期13卷 1071-1086页

作者： MA Gailing GOU Qianqian WANG Guohua qu jianjun College of Geographical Sciences Shanxi Normal UniversityLinfen 041004China Northwest Institute of Eco-Environment and Resources Chinese of Academy of SciencesLanzhou 730000China

Bacterial and fungal communities play critical roles in reestablishing vegetation structure,function and biodiversity in ecosystem restoration in arid and semi-arid ***,the long-term successional changes in bacterial and fungal communities that occur with artificial vegetation development are not fully *** this study,we investigated the successional changes in bacterial and fungal communities in Caragana korshinskii *** over a period of 50 a(6,12,18,40 and 50 a)and their relationships with key soil environmental factors in a typical agro-pastoral ecotone,northern *** results showed that bacterial and fungal diversities(α-andβ-diversity)were significantly affected by plantation age;moreover,the change in fungal community was more evident than that in bacterial *** samples from 12 a plantation had the highest(P<0.05)bacterial and fungalα-diversity(i.e.,abundance-based coverage estimator(ACE)and Chao1 index)at 0-10 cm depth compared with other ***,soil samples from plantation at the late recovery stage(40-50 a)had the highestα-diversity at 10-20 cm *** bacterial community was not significantly affected by plantation age at the genus level;but,soil fungal community was significantly affected at the genus ***,Mortierella and Chaetomium were the dominant genera at natural recovery stage(0 a);Inocybe was the dominant genus at the early recovery stage(6-12 a);Inocybe and Mortierella were the dominant genera at the mid-recovery stage(12-40 a);And Mortierella,Cladosporium and Humicola were the dominant genera at the late recovery stage(40-50 a).Redundancy analysis(RDA)showed thatβ-glucosidase activity,total nitrogen and soil organic carbon were closely associated with bacterial community composition,while alkaline phosphatase,urease activity and total nitrogen were associated with fungal community composition,indicating that changes in enzyme activity and soil nutrients were the most important determ

关键词： bacteria fungi diversity dominant genus ecological pattern Caragana korshinskii

Diversity of soil bacteria and fungi communities in artificial forests of the sandy-hilly region of Northwest China

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Journal of Arid Land 2023年第1期15卷 109-126页

作者： GOU Qianqian MA Gailing qu jianjun WANG Guohua College of Geographical Sciences Shanxi Normal UniversityTaiyuan 030000China Key Laboratory of Desert and Desertification Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China Laboratory of Watershed Hydrology and Ecology Linze Inland River Basin Comprehensive Research StationChinese Ecosystem Research NetworkNorthwest Institute of Ecology and Environmental ResourcesChinese Academy of SciencesLanzhou 730000China

Soil erosion is a serious issue in the sandy-hilly region of Shanxi Province,Northwest *** has been gradual improvement due to vegetation restoration,but soil microbial community characteristics in different vegetation plantation types have not been widely *** address this,we analyzed soil bacterial and fungal community structures,diversity,and microbial and soil environmental factors in Caragana korshinskii Kom.,Populus tomentosa Carr.,Populus simonii Carr.,Salix matsudana Koidz,and Pinus tabulaeformis *** were no significant differences in the dominant bacterial community compositions among the five forest *** alpha diversity of the bacteria and fungi communities showed that ACE(abundance-based coverage estimator),Chao1,and Shannon indices in *** forest were significantly higher than those in the other four forest types(P<0.05).Soil organic matter,total nitrogen,and urease had a greater impact on bacterial community composition,while total nitrogen,β-glucosidase,and urease had a greater impact on fungal community *** relative abundance of beneficial and pathogenic microorganisms was similar across all forest *** on microbial community composition,diversity,and soil fertility,we ranked the plantations from most to least suitable as follows:***,***,***,***,and ***.

关键词： microbial community composition artificial forest bacteria fungi diversity sandy-hilly region

Effects of wind speed,underlying surface,and seed morphological traits on the secondary seed dispersal in the Tengger Desert,China

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Journal of Arid Land 2024年第4期16卷 531-549页

作者： qu Wenjie ZHAO Wenzhi YANG Xinguo WANG Lei ZHANG Xue qu jianjun Northwest Institute of Eco-Environment and Resources Chinese Academy of SciencesLanzhou 730000China Key Laboratory of Restoration and Reconstruction of Degraded Ecosystems in Northwestern China of Ministry of Education Ningxia UniversityYinchuan 750021China University of Chinese Academy of Sciences Beijing 100049China School of Ecology and Environment Ningxia UniversityYinchuan 750021China

The maintenance of sand-fixing vegetation is important for the stability of artificial sand-fixing systems in which seed dispersal plays a key *** on field wind tunnel experiments using 11 common plant species on the southeastern edge of the Tengger Desert,China,we studied the secondary seed dispersal in the fixed and semi-fixed sand dunes as well as in the mobile dunes in order to understand the limitations of vegetation regeneration and the maintenance of its *** results indicated that there were significant variations among the selected 11 plant species in the threshold of wind speed(TWS).The TWS of Caragana korshinskii was the highest among the 11 plant species,whereas that of Echinops gmelinii was the *** morphological traits and underlying surface could generally explain the *** the secondary seed dispersal processes,the proportions of seeds that did not disperse(no dispersal)and only dispersed over short distance(short-distance dispersal within the wind tunnel test section)were significantly higher than those of seeds that were buried(including lost seeds)and dispersed over long distance(long-distance dispersal beyond the wind tunnel test section).Compared with other habitats,the mobile dunes were the most difficult places for secondary seed *** seeds were the easiest to be found in the semi-fixed sand dunes,whereas fixed sand dunes were the best sites for seeds that dispersed over long *** results of linear mixed models showed that after controlling the dispersal distance,smaller and rounder seeds dispersed *** index and wind speed were the two significant influencing factors on the burial of *** explanatory power of wind speed,underlying surface,and seed morphological traits on the seeds that did not disperse and dispersed over short distance was far greater than that on the seeds that were buried and dispersed over long distance,implying that the processes and mechanisms of burial and lo

关键词： seed dispersal seed morphological traits wind speed vegetation regeneration wind tunnel Tengger Desert

Pulsatory characteristics of wind velocity in sand flow over typical underlying surfaces

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Science China Earth Sciences 2007年第2期50卷 247-253页

作者： ZHANG KeCun qu jianjun ZU RuiPing FANG HaiYan Key Laboratory of Desert and Desertification Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of SciencesLanzhou 730000China

Pulsatory characteristics of wind velocity in sand flow over Gobi and mobile sand surface have been investigated experimentally in the wind tunnel. The primary goal of this paper is to reveal the relation- ship between pulsatory characteristics of instantaneous wind speed in sand flow and the motion state of sand grains. For a given underlying surface, pulsation of wind velocities in sand flow on different heights has a good correlation. As the space distance among different heights increases, fluctuation of instantaneous wind speed presents a decreasing trend and its amplitude is closely related to the mo- tion state of sand grains and their transport. Pulsatory intensity increases with the indicated wind speed, but its relative value does not depend on it, only agrees with height.

关键词： underlying surface sand flow pulsation of wind speed