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Dynamic Mechanism Research on the Secondary Blown Sand Disaster in the 110 MW Photovoltaic Arrays of the Hobq Desert
Guo Caiyun, Han Zhiwen, Li Aimin, Zhong Shuai
Journal of Desert Research    2018, 38 (2): 225-232.   doi: 10.7522/j.issn.1000-694X.2016.00142
Abstract(135)   PDF (3316KB) (273)  
In order to explain the dynamic mechanism of sand erosion and accumulation of sandy surface under the interference of photovoltaic facilities, two cross sections were set in the 110 MW photovoltaic Plant located in the Hopq Desert. MetOne 014A/024A 8 channel anemometer (with CR200X data collection instrument) were used, and the average wind speed of four heights (20 cm, 50 cm, 100 cm, 200 cm) around the photovoltaic panel were observed simultaneously. The variations of wind velocity around the photovoltaic panel were analysed. Results showed that:(1) The photovoltaic facilities resulted in the variations of flow field on both sides of the photovoltaic panels and generated four secondary flow field zones, namely, the conflux accelerating speed-up zone under the panels, the resistance decelerating zone in front and back of the panels, the uplift zone above the panels and the recovery area between the plates; Moreover, there were significant differences in the flow field pattern between the upwind edge region and the area within the photovoltaic plants. (2) The dynamical distribution indicated by develop degree of the flow field pattern was identical with the surface erosion and accumulation situation basically. (3)Vegetation can increase the surface roughness effectively, and reduce the transit speed below 50 cm near surface, and prevent the occurrence and aggravation of the sand erosion. (4) The conflux accelerating zone under the panels and the reverse vortex around the panels were the main dynamic mechanisms of shaping wind erosion ditches (PITS) and sand accumulation belts, respectively.
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Climatic Change Reflected by Geochemical Features in Datong Basin, North China since 220 ka BP
Liu Miaomiao, Su Zhizhu, Kong Mengyuan, Zhang Caixia, Li Jinchang, Wang Guoling, Li Xiang
Journal of Desert Research    2018, 38 (2): 278-285.   doi: 10.7522/j.issn.1000-694X.2017.00104
Abstract(126)   PDF (1974KB) (177)  
The Datong Basin developed thick fluvio-lacustrine sediments in Quaternary period and aeolian loess overlied, which recorded an abundant information on past climatic and environmental changes. To analyze the climate changes, we mainly use the primary oxides as climate proxies to establish the age framework according to stratigraphic dating data, combining formation susceptibility and particle size. The results showed that:(1)The average content of chemical elements of the sediments in the constant formation was SiO2 > Al2O3 > CaO > Na2O > TOFE > K2O > MgO from high to low,the sedimentary facies of different elements are obviously different, reflecting elements vary with climate change. (2) The Datong Basin climate change experienced the following 5 stages:The research area climate was warm-humid during the Middle Pleistocene of 220-199 ka BP, and cold-dry climate occurrenced during the Middle Pleistocene of 199-138 ka BP, and warm-humid climate occurrenced during the last interglacial period of 138-71 ka BP, and cold-dry climate was showed during the last glacial stage of 71-11 ka BP, and the Holocene periodclimate was alternate variationsof warm-wet and cold-dry. However, during each period there is still less-grade climate fluctuation level. (3) These climatic changes is similar with Salawusu River and Inner Mongolia Daihai region roughly in the same latitude, and are well accordant with the global climatic change reflected by the deep-sea oxygen isotope and the polar ice core, showing a consistency in time of climatic change between the study area and the global. The climate change in this area is regional response of global climate change influenced by the East Asian winter and summer monsoon.
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Advances in the Study of Microbial Ecology in Desert Soil
Li Ting, Zhang Wei, Liu Guangxiu, Chen Tuo
JOURNAL OF DESERT RESEARCH    2018, 38 (2): 329-338.   doi: 10.7522/j.issn.1000-694X.2017.00113
Abstract(124)   PDF (1769KB) (263)  
The desert ecosystem accounts for a third of the earth's land area, and is a vital part of the biogeochemical cycle. Because of the bad environmental condition in the desert including extreme drought, lack of vegetation, strong UV radiation, deserts used to be considered lifeless, however there are a lot of microbial resources in this harsh environment especially in the desert soil which enriched with a large number of microbes. These microorganisms involve in the whole earth biochemical circulation of desert ecosystem, adjust the important ecological processes and play an important role in the restoration and stability of the desert ecosystem, its research is of ecological significance. With the development of molecular biological technique, molecular biological technique are revealed. In this paper, the structure characteristics, functionality of desert soil microbial community and the relationships between microbial community, microorganism and plant, microorganism and environment are reviewed. Aim to further understand the desert soil microorganism and to summarize the deficiency of ecological understanding of desert microorganism, provide reference for the ecological research direction of desert microorganism.
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Dynamic Environment of Blown Sand at Honglianghe River of Qinghai-Tibet Plateau
Xie Shengbo, Yu Wenbo, Qu Jianjun, Pang Yingjun
JOURNAL OF DESERT RESEARCH    2018, 38 (2): 219-224.   doi: 10.7522/j.issn.1000-694X.2016.00146
Abstract(109)   PDF (4236KB) (289)  
Sand land in the Honglianghe River area of Qinghai-Tibet Plateau is widespread, and its blown sand activity rules are currently not sufficiently understood, which is not conducive to targeted sand prevention and control work. Therefore, the dynamic environments characteristics of blown sand at Honglianghe River are investigated using different methods, such as field observation, laboratory analysis, and calculation. The direction of yearly sand-moving wind at Honglianghe River is usually found to originates from the north direction, and the sand drift potential (DP) and the resultant drift potential (RDP) are high during winter and spring, low during summer and autumn. The variation of the monthly resultant drift direction (RDD) is stable. The yearly sand drift potential is 249.84 VU, which indicates an intermediate wind energy environment. The yearly resultant drift potential is 242.92 VU, and the yearly index of directional wind variability (RDP/DP) is 0.97, which indicate a high ratio. The yearly resultant drift direction is 173.8, which indicate a south direction. The yearly total sand transport quantity of the eight directions of Honglianghe River is 434.33 kg·m-1, and the sand transport quantity of the southwest direction reached its maximum. The research results have guiding significance for controlling sand hazards of the locale.
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Process, Spatial Pattern and Driving Mechanisms of the Aeolian Desertification in the Alxa Plateau from 1975 to 2015
Wan Wei, Yan Changzhen, Xiao Shengchun, Xie Jiali, Qian Dawen
JOURNAL OF DESERT RESEARCH    2018, 38 (1): 17-29.   doi: 10.7522/j.issn.1000-694X.2017.00086
Abstract(86)   PDF (9708KB) (389)  
A total of 7 dataset were obtained about genetic types and degree of aeolian desertification in 1975, 1990, 1995, 2000, 1995, 2010 and 2015 in the Alxa Plateau using Remote Sensing (RS) images and Geographic Information System (GIS). We analyzed the genetic types, area and spatial distribution changing about degree of aeolian desertification in the Alxa Plateau in recent 40 years. And we investigated aeolian desertification degree in the Alxa Plateau with aeolian desertification index (ADI) quantificationally, which suggested that it was deteriorative before 2000 and then began to take a favorable turn after 2000. Besides, the spatial variation patterns about the different types of aeolian desertification was investigated by the model of center of gravity migration, and the hotspots distribution of aeolian desertification dynamics by overlay analysis in the Alxa Plateau. Finally, natural and human driving factors were quantified and identified with principal component analysis (PCA). The results showed that in recent 40 years (especially since 2000), human factors, including population pressure, animal husbandry and cultivation, afforestation, industrial and mining exploitation, were major driving factors influencing the aeolian desertification dynamics in the Alxa Plateau. Another critical driver was climate change (rainfall, temperature and the maximum wind speed) in this region.
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Development Characteristics of Biological Crusts under Artificial Vegetation in Southern Mu Us Sandy Land
Wu Yongsheng, Yin Ruiping, Tian Xiumin, Hasi
JOURNAL OF DESERT RESEARCH    2018, 38 (2): 339-344.   doi: 10.7522/j.issn.1000-694X.2016.00161
Abstract(86)   PDF (2095KB) (174)  
Widespread biological crusts have been developed at the dune surface after implementation of desertification control and ecological rehabilitation projects in the sandy area in Northern China. Clarifying the relationships between characteristics of biological crusts development and different types of artificial vegetation has significant influence on the ecological rehabilitation of damaged ecosystem. Thicknesses, shear strength, coverage of biological crusts were examined under different types of artificial vegetation (Hedysarum mongdicum, Populus simonii, Salix psammophila, Amorpha fruticosa and Sabina vulgaris) in southern Mu Us sandy land by field investigation methods. The results showed that characteristics of biological crusts development under different vegetation types varied greatly. Thicknesses, shear strength, coverage of biological crusts under P. simonii site significantly higher than other sites (P<0.05). Coverage of biological crusts under H. mongdicum and S. psammophila site was lower relatively. P. simonii site were dominated by mosses crusts while the other sites were dominated by algae crusts. Correlation analysis indicated that coverage of biological crust decreased with increasing of vegetation cover, increasing with surface (0-5 cm) water contents of soil. These results suggest that plantation of P. simonii is recommended for establishment of biological crust, and plantation of S. psammophila with H. mongdicum is not conductive to development of biological crusts.
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Population Structure Characteristics of Population euphratica in the Lower Reaches of Tarim River
Zhou Yingying, Chen Yaning, Zhu Chenggang, Chen Yapeng, Chen Xiaolin
Journal of Desert Research    2018, 38 (2): 315-323.   doi: 10.7522/j.issn.1000-694X.2017.00103
Abstract(85)   PDF (2537KB) (260)  
Population structure characteristics can reflect the living conditions and future trends of one population. In this paper, we investigated the living status of Populus euphratica in the lower reaches of Tarim River, after years of ecological water conveyances to restore the ecosystem. The population density, age structure, sex ratio structure and spatial structure of P. euphratica were analyzed based on field investigation. The results indicated that the pattern of age structure of P. euphratica in the lower reaches of Tarim River followed the "inverted pyramid" pattern. The population dynamics index, population density, had similar patterns with that of the age structure, indicating the declining trend of P. euphratica will continue. The P. euphratica was significantly male-biased, and this deviation increased with the deterioration of habitats. The distribution pattern of P. euphratica showed a significant cluster distribution with no intensity difference among them. After 18 years, ecological water conveyances, the degradation trends of the P. euphratica distributed far from the river have not yet completely reversed although the ecological conditions near the river have improved. The ecological water conveyances along a natural river channel created a too narrow flooded area to improve the population regeneration rates. Therefore, during the processes of ecological water conveyances, artificial measures are suggested to be taken to extend the flooded area to provide conditions for the reproduction and regeneration of the P. euphratica.
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Estimation of Carbon Residence Times and Sequestration Potential of Grassland and Cropland Ecosystem in the Loess Plateau
Guo Ding, Li Xudong, Wang Jing, Fu Hua
JOURNAL OF DESERT RESEARCH    2018, 38 (2): 363-371.   doi: 10.7522/j.issn.1000-694X.2017.00111
Abstract(85)   PDF (2615KB) (169)  
A Bayesian probability inversion was applied to estimate the Carbon residence times and sequestration potential of grassland and cropland ecosystems in the Loess Plateau. The result shows that the shortest Carbon residence times ranged from 25 to 203 days were in the aboveground and belowground biomass pools, the metabolic litter pools and the active soil organic matter (SOC) pools, excluding the aboveground biomass pool in cropland. The structure litter pools had Carbon residence times between 2.4 and 3 years. The longest Carbon residence times were 57.4-79.6 years and 593-598 years in the slow and passive SOC pools, respectively. Carbon residences times for the belowground biomass pools were longer in grassland than those in cropland, whereas Carbon residences times in the metabolic litter and slow SOC pools in grassland were shorter than those in cropland. According to the parameters derived from the inversion model, the SOC pools in grassland and cropland would reach a stable state in 250 years. The Carbon sequestration potential would be 3 130 and 2 680 g C·m-2, respectively, in grassland and cropland ecosystems. The application of manure could result in higher (4 000 g C·m-2) Carbon sequestration. Compared to that in grassland, the application of manure and the longer Carbon residence times of soil pools could lead to higher SOC sequestration in cropland ecosystem.
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Spatial and Temporal Variations of NDVI in Gansu, China from 2000 to 2014
Cao Bo, Zhang Bo, Ma Bin, Wang Guoqiang, Tang Min, Zhang Yaozong, Jia Yanqing
JOURNAL OF DESERT RESEARCH    2018, 38 (2): 418-427.   doi: 10.7522/j.issn.1000-694X.2016.00171
Abstract(85)   PDF (4781KB) (159)  
Based on MODIS NDVI and climate datasets during 2000-2014, used linear regression and correlation analysis, the spatiotemporal variations of NDVI in Gansu and their linkage with regional climate change were analyzed. The results showed that in the last 15 years, average NDVI of growing season, spring, summer and autumn all showed an increasing trend. The trend of summer was the most significant at regional scale, with a rate of 0.071/10 a (P<0.01). At pixel scale, the area of increasing trend in growing season was the largest, area with excellent (P<0.01) and significant (0.01 < P < 0.05) increasing trend covered 50.03% and 14.44% of the whole vegetation area respectively. Precipitation and humid index are the most important factors of vegetation growth in growing season and summer. Temperature, precipitation and humid index played equal roles in spring, temperature was the most important driving factor in autumn. The lag effect of temperature was obvious to NDVI in growing season. The precipitation and humid index in last season had effect on the vegetation growth of the coming season.
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The Spatial Variation and Grain Size Character of Different Land Cover Types in the Ulanbuh Desert
Song Jie, Chun Xi
JOURNAL OF DESERT RESEARCH    2018, 38 (2): 243-251.   doi: 10.7522/j.issn.1000-694X.2016.00154
Abstract(84)   PDF (4056KB) (293)  
The paper is based on the systematic sampling of the Ulanbuh Desert, one of the source areas of dust storm in China, and the grain size characteristics and spatial variation of surface sediments between different land cover types in the desert are analyzed. It is concluded that most of the grain size of surface sediments in the desert are medium and fine sand, and the average particle size is 2.84 φ. According to different land cover types and different spatial distribution laws, the grain size distribution of the surface sediments in the desert was the result of the interaction of the sediment source, the terrain and the carrying capacity. The saline alkali land in the middle of the desert, the farming land in the northeast and the sandy land in the desert should be the sources of the sand dust. Therefore, according to the different land cover types in the Ulanbuh Desert, to set up suitable models of initial plant population structure is the main method to control desertification.
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