Gobi Region Research Articles

Nebkha dune morphology in the gobi deserts of northern China and potential implications for dust emission

AbstractNebkhas (coppice dunes) have formed throughout the gobi desert regions of China in response to the decreased near‐surface wind speed caused by vegetation, combined with deposition of aeolian sediment in and around the vegetation. Although nebkhas have been extensively studied on several land surfaces, they have not yet been fully described where they form in areas of gobi desert. Based on field investigations of nebkha morphology and adjacent land surface sediment content on and inside the surface of these dunes, the following were found: (i) the nebkhas that develop in gobi deserts consist of two types – dunes with or without a depositional tail (a shadow dune); (ii) the nebkhas in the area of gobi desert were smaller than those found in sandy deserts, oases, or other areas with a rich sediment source, with a mean height of 0.28 m, mean width 1.63 m and mean length 1.34 m; and (iii) the dune height, length and width were significantly positively linearly related to the vegetation height, length and width. These patterns were similar at all four of the study sites, but the relationships with dune width differed among the sites. The average particle‐size distributions on and inside the vegetation did not differ between the four sites. However, significant spatial differences in the sediments on and inside the dunes indicate that nebkhas can capture both local and distant sediments driven by the wind. These findings suggest a potential role of nebkhas in dust emission, although this role must be confirmed in future research.

Research on Rapid Vegetation Extraction Based on UAV image in Desert and Gobi Area

In this study, high-resolution uav platform and motion structure modeling technology were used to research. Based on uav-image, vegetation coverage was automatically estimated by decision tree algorithm, and superimposed with DEM data to analyze the spatial distribution characteristics of vegetation in gobi region and its relationship with terrain. The results show that, based on the high definition image of UAV, the uav high precision image analysis platform is used to extract the sparse vegetation coverage in the Gobi region, and good accuracy is obtained. The use of uav image data has a good applicability for analyzing the sparse vegetation distribution characteristics in the Gobi region.

Identification and quantitative analysis of dust trajectories in the Hexi Corridor

Dust storms in Northwest China are a major component of global dust storms and it is important to be able to identify and quantitatively analyze their dust trajectories. In this study, the dust events, sources, and transport paths in the Hexi Corridor were identified using ground-measured PM10 data, Navy Aerosol Analysis and Prediction System (NAAPS) data, the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model, and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) data. Based on these data, the dust trajectories were then screened. Dust events from five cities in the Hexi region were determined for 2015–2018. Next, five main areas affecting the Hexi region were defined; which included the Gobi region between Xinjiang and Mongolia (XG), Taklimakan Desert (TD), Kumtag Desert (KD), Qaidam Basin (QB), and Badain Jaran and Tengger Deserts (BJTD). We quantified the contributions of the dust trajectories for these five main areas and determined that the major areas that affect the Hexi region are the BJTD and KD, which are located close to the study area. The contribution of the dust trajectories in XG is smaller, owing to its higher vegetation coverage, greater precipitation, and larger particulate matter size. Of the five main areas that affect the Hexi region, the dust intensity in TD is the highest. However, its dust trajectory contribution to the study area is lower. This is because the dust is not elevated to the free atmosphere readily by the easterly wind, owing to the closed mountain basin location. The contribution of the dust trajectories in the QB to the study area is the lowest, mostly due to the low dust intensity in this region and the obstruction of dust trajectories by the Qilian Mountains.

Small mammal communities of the Mongolian Gobi Region: diversity and impacts of mining

Small mammal communities of the Mongolian Gobi Region: diversity and impacts of mining

Photosynthetic inner antenna CP47 plays important roles in ephemeral plants in adapting to high light stress

Throughout 3.5 billion years of evolution, photosynthesis of land plants has developed a complicated antenna system to cope with the ever-changing environments. The antenna system of photosystem (PS) II includes the outer antennae and inner antennae. The inner antennae CP43 and CP47, located in the closest peripheral of PSII reaction center (RC), play important roles in facilitating excitation energy transport from the outer antennae to the PSII RC. Although PSII RC is the last station of energy transport, it is the inner antenna CP47, not the RC, which possesses the lowest energy level in PSII. Berteroa incana (B. incana), which is a vascular plant grown in the Gobi region, can sustain very high photosynthesis capacity under very high light conditions. It has been discovered that the thylakoid membrane of B. incana possesses a unique low fluorescence emission spectrum because the fluorescence emission of CP47 (695 nm) is the main fluorescence emission peak of PSII. In this paper, the thylakoid membrane, isolated from B. incana grown under a light condition of 100 μM photons m−2 s-1 and subjected to high light treatment (1600 μM photons m-2 s-1 for 1.5 h or 3 h) was employed for the research. It has been found that the high fluorescence emission of CP47 decreased remarkably upon exposure to the high light treatment. Further observation revealed that the drastic changes in the CP47 fluorescence emission were accompanied by a slight reduction in the amount of CP47 and an enhancement of the CP29-LHCII-CP24 assembly. It is proposed that CP47 enables the functional switch between the excitation energy transfer towards PSII RC, and the overexcitation quenching in the PSII core. Together with CP43, CP47 plays important roles in regulating excitation energy distribution in PSII core complexes.

Field study of atmospheric boundary layer observation in a hilly Gobi Desert region and comparison with the CALMET/CALPUFF model

Abstract A field campaign consisting of atmospheric boundary layer (ABL) observations and tracer experiments was conducted in September 2016 in a hilly region of the Gobi Desert in northwest China. High-frequency wind shears were observed between 70 and 200 m based on both 100-meter tower data and wind profiles. The ABL observations indicated that sub-layers of different atmospheric stability present within the ABL weakened the vertical transfer of momentum and tracer gas, resulting in low wind speed and high surface concentration. The CALMET model showed thermal heterogeneity to some extent in the temperature fields and mixing height distributions, and large deviations in the friction velocity between the model and observations were noted. The comparison of the CALPUFF model with the tracer measurements indicated a general tendency toward under-prediction of the concentration in the far distance because of wind shears and vertical thermal discontinuity. The results of the SCIPUFF model showed the same trend as those of CALPUFF, and comparisons demonstrated a good consistency of the two models.

The slope creep law for a soft rock in an open-pit mine in the Gobi region of Xinjiang, China

The lithology of the strata in the Gobi region of the Xinjiang autonomous region of China is mainly composed of mudstone, silty mudstone, and other soft rocks. Because of the low strength of the rock mass and the serious effects of physical weathering in this area, the slope stability in open-pit mines is poor, and creep deformation and instability can readily occur. Taking the Dananhu No. 2 open-pit mine as a typical example, the creep test of a mudstone sample under different stress levels was studied. Then, based on a bottom friction experiment and a FLAC3D numerical simulation, the deformation and failure processes of the slope were analyzed. The stress–displacement curve and the displacement–time curve for the monitoring points were plotted to obtain the relationship between the stress and displacement for the slope of the soft rock. The results showed that the long-term strength of the mudstone was between 8.0 and 8.8 MPa, and that stable creep occurred when the slope was under low stress. The potential failure mode for this type of slope is that the front edge creeps along the weak layer and then a crack is formed at the trailing edge of the slope. When the crack penetrates the weak layer, cutting bedding and bedding sliding occur. The deformation process of the stable creep slope includes an initial deformation stage, an initial creep stage, a constant velocity creep stage and a deceleration creep stage.

THE LIMITATIONS OF WINTERING AWAY FROM CUSTOMARY PASTURES IN RELATION TO DZUD IN MONGOLIA’S GOBI REGION

Abstract This article, based on ethnographic research in a Gobi district in Mongolia, focuses on herders ‘wintering away’ from customary winter campsites to access better pasture elsewhere. Because of the drawbacks associated with wintering at non-customary as opposed to ‘home’ pastures, many herders consider ‘wintering away’ to be a last resort. In the 2009–10 dzud (winter disaster), in Bayanlig soum, most households that wintered away were hit by unusually heavy snowfall and suffered higher livestock losses than those households that stayed at their customary campsites. While herders’ migration decisions are guided by expert knowledge of the environment, complicating factors and high uncertainty can contribute to livestock losses despite their best efforts. Mobility is essential to herders’ success in a variable environment, but not all forms and instances of migration are equally beneficial. This article draws on herders’ accounts to explore a migration dilemma in the Gobi that may become more common.

Hidden treasure of the Gobi: understanding how water limits range use of khulan in the Mongolian Gobi

Most large herbivores in arid landscapes need to drink which constrains their movements and makes them vulnerable to disturbance. Asiatic wild ass or khulan (Equus hemionus) were widespread and abundant throughout the arid landscapes of Central Asia and Mongolia, but have undergone dramatic population declines and range constrictions; denying khulan access to water is believed to have played a major role. Mongolia’s South Gobi Region now houses the world largest remaining khulan population, but is undergoing rapid land use changes. Khulan water use is poorly understood, largely due to the difficulty of mapping waterpoints used by khulan throughout their exceptionally large ranges, prone to high variations in precipitation. We used the special movement path characteristics of GPS tagged khulan to show us where water is located. We identified 367 waterpoints, 53 of which were of population importance, characterized the seasonal and circadian use, and identified snow cover as the most important variable predicting khulan visits during the non-growing season, and vegetation greenness during the growing season. Our results provide a data layer to help guide a regional khulan conservation strategy, allow predictions for other part of the global khulan range, and illustrates the overall importance of waterpoints for dryland herbivores.

Spatial heterogeneity of surface sediment grain size and aeolian activity in the gobi desert region of northwest China

Studies have previously discussed characteristics of aeolian activity for different gravel densities on gobi surfaces. However, the significance of the spatial heterogeneity of its surface to sand flow over its surface and to dust emissions from the region has not been clearly demonstrated. This is also the case for spatial variation in the aeolian environment. Accordingly, this study established two observation transects, both through the desert pavement area and the dune field in the gobi desert region of northwest China, to measure surface sediment grain size, wind speed and sand transport along these transects. Results showed that in areas where surface gravel content decreased and mobile sand dunes increased, surface sediments were better sorted and grain-size distribution changed from multimodal to roughly unimodal. Furthermore, sand transport increased significantly and properties of aeolian activity varied markedly within a short distance. This extreme variation in both grain-size parameters and in sand transport indicated that strong spatial heterogeneity exists in the aeolian environment of the study area. Furthermore, dune fields within gobi area are likely the main cause of sand flow over its surface as well as dust emissions from the region itself. The findings in this study have universal applicability in gobi regions with uneven surface properties in other arid areas.

Atmospheric pollution assessment near potential source of natural aerosols in the South Gobi Desert region, China

ABSTRACTRapid economic growth, a high degree of urbanization and the proximity of a large number of desert and semidesert landscapes can have a significant impact on the atmosphere of adjacent territories, leading to high levels of atmospheric pollution. Therefore, identifying possible sources of atmospheric pollution is one of the main tasks. In this study, we carried out an analysis of spatial and temporal characteristics of five main atmospheric pollutants (PM2.5, PM10, SO2, NO2, and CO) near potential source of natural aerosols, affecting seven cities (Wuhai, Alashan, Wuzhong, Zhongwei, Wuwei, Jinchang, Zhangye), located in immediate proximity to the South Gobi deserts. The results, obtained for the period from 1 January 2016 to 31 December 2018, demonstrate total concentrations of PM2.5 and PM10 are 38.2 ± 19.5 and 101 ± 80.7 μg/m3 exceeding the same established by the Chinese National Ambient Air Quality Standard (CNAAQS), being 35 and 70 μg/m3, respectively. Based on the data from Moderate Resolution Imaging Spectroradiometer (MODIS) for the whole period, Clean Сontinental (71.49%) and Mixed (22.29%) types of aerosols prevail in the region. In the spring and winter seasons maximum concentrations of pollutants and high values of Aerosol Optical Depth (AOD) in the region atmosphere are observed. PM2.5 and PM10 ratio shows the presence of coarse aerosols in the total content with value 0.43. The highest concentrations of pollutants were in the period of dust storms activity, when PM2.5 and PM10 content exceeded 200 and 1000 µg/m3, and AOD value exceeded 1. UV Aerosol Index (UVAI), Aerosol Absorbing Optical Depth (AAOD), and Single Scattering Albedo (SSA), obtained from Ozone Monitoring Instrument (OMI), demonstrate the high content of dust aerosols in the period of sandstorms. Analysis of backward trajectories shows that dust air masses moved from North to Northwest China, affecting large deserts such as Taklamakan, Gurbantunggut, Badain Jaran, Tengger, and Ulan Buh deserts.

Intermittent Aeolian Saltation Over a Gobi Surface: Threshold, Saltation Layer Height, and High‐Frequency Variability

AbstractGobi is a type of desert pavement in Asia over which aeolian saltation generates atmospheric dust. However, the high‐frequency behavior of aeolian saltation over gobi is still poorly understood. In this study, coupled high‐frequency observations of three‐dimensional (3‐D) wind speed (U) and saltation particle count rate in a vertical array of Sensit sensors were performed in a gobi region of Milan County, southern Xinjiang, China. The results revealed that aeolian saltation over a gobi surface exhibited an intermittent phenomenon, and the level of the intermittency was governed by the relative wind strength (s), which is consistent with that of sand surfaces. The threshold wind speed (Ut) decreased exponentially with increasing transport activity parameter (AP), and a prominent decrease in Ut was examined when the AP values reached 0.7; comparatively, for sand surfaces, a linearly declining trend occurred over the whole AP range of 0–1. The saltating particles over the gobi surface were distributed in layers of 0.08–0.30 m with an average value of 0.20 ± 0.04 m, which was significantly larger than that of sand surfaces. The relationship between the instantaneous sand transport rate (Q) and U over the gobi surface was also relatively poor and could be improved by lagging Q by 2 s. The mechanism for the collision between saltating particles and the gobi bed, which is rigid and complex in texture, was significantly different from that of the soft and deforming sand bed, causing the difference in aeolian saltation between gobi and sand surfaces.

Desertification Information Extraction Along the China–Mongolia Railway Supported by Multisource Feature Space and Geographical Zoning Modeling

The China–Mongolia railway is the core foundation for the construction of traffic connection in the China–Mongolia–Russia economic corridor. Long-term desertification has brought significant ecological risks to the railway area. Owing to the large variety of vegetation cover in this region, desertification information is easily confused with other weak vegetation cover information. This article proposes a refined desertification information extraction method based on multisource feature spaces and geographical zoning modeling. First, based on the geographical zoning, land cover, and vegetation coverage data for Mongolia, the railway area is divided into the Central provinces and their northern region, the Eastern Mongolian Plateau, and the Southern Gobi region. According to the vegetation coverage characteristics and the applicability of various feature space models to different geographical regions, Albedo–normalized difference vegetation index, Albedo–modified soil adjusted vegetation index, and Albedo–topsoil grain size index feature space models were constructed for three geographical regions. Faced with new challenges presented by global warming and the impact of monsoons on the classification and extraction of desertification information, we established a desertification classification system with six levels (severe desertification, high desertification, medium desertification, low desertification, withered grassland, and nondesertification) and complete desertification information extraction. The results show that the overall classification accuracy of the method selected in this article is 85.21%. We further analyzed the mechanism of this method, compared it with previous studies, and thereby proved that this method is feasible to extract the fine information of desertification in large areas and complex geographical environments.

Characteristics of Aerosols over the Summer Monsoon Transition Zone

A survey was conducted in the summer monsoon transition region of China. By combining data from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSOs) and Moderate Resolution Imaging Spectroradiometer (MODIS), the effects of East Asian summer monsoon circulation on the spatial distribution of aerosol, as well as the response mechanisms of different aerosols in an abundant and a deficient summer monsoon year, were analyzed. It was found that, in the summer monsoon transition region, the aerosol optical depth (AOD) in abundant monsoon years was lower than that in deficient years. Only in the Gobi Desert region of the Loess Plateau, the AOD in abundant monsoon years was significantly larger than that in deficient years. When the AOD was less than 0.06, the frequency of dust aerosol was higher than that of polluted aerosol in both the abundant and deficient monsoon years. When the AOD was over 0.06, the frequency of polluted aerosol was higher than that of dust aerosol in both the abundant and deficient monsoon years. In summer, the AOD was larger and the frequency of polluted aerosol in abundant monsoon years was higher than that in deficient years.

Гандуу бүсийн ургамлын орон зайн тархалт: тюрингийн хэлбэршил ус гачиг нөхцөлд илрэх нь

Since the plants in the Gobi desert region are sparsely distributed on a vast bare field, it is extremely difficult to accurately observe from the satellite. For this reason, the reflectance of dry soil is very high and the reflectance of slightly distributed plants is eliminated by soil reflection. As a result, the pixel’s Normalized Difference Vegetation Index (NDVI) value of desert plants shows a smaller value than the ground measurement. In this study, we succeeded to analyze the Turing (1952) pattern of vegetation abundance using the method of spectral un-mixing for satellite data of the Gobi plants. It is shown that the fraction of the vegetation endmember after pixel un-mixing has a remarkably high correlation (R2=0.51 in Landsat-8 and R2=0.41 in Sentinel-2) with the ground truth value of vegetation coverage.

Metal-Tolerant Fungal Communities Are Delineated by High Zinc, Lead, and Copper Concentrations in Metalliferous Gobi Desert Soils.

The soil fungal ecology of the southern Gobi region of Mongolia has been little studied. We utilized the ITS1 region from soil DNA to study possible influences soil metal concentrationson soil fungal community variation. In the sample network, a distinctive fungal community was closely associated with high zinc (Zn), lead (Pb), and copper (Cu) concentrations. The pattern of occurrence suggests that high metal concentrations are natural and not a product of mining activities. The metal-associated fungal community differs little from the "normal" community in its major OTUs, and in terms of major fungal guilds and taxa, and its distinctiveness depends on a combination of many less common OTUs. The fungal community in the sites with high metal concentrations is no less diverse than that in areas with normal background levels. Overall, these findings raise interesting questions of the evolutionary origin and functional characteristics of this apparently "metal-tolerant" community, and of the associated soil biota in general. It is possible that rehabilitation of metal-contaminated mined soils from spoil heaps could benefit from the incorporation of fungi derived from these areas.

Aerosol clustering in an urban environment of Beijing during (2005–2017)

In depth and detailed study about various classes of aerosols over an urban city of Beijing has been carried out, with the help of cluster technique during the period from (2005–2017). Aerosol Robotic Network (AERONET), retrieved data for Aerosol Optical Depth (AOD), Angstrom Exponent (AE), Extinction Angstrom Exponent (EAE), Absorption Angstrom Exponent (AAE), Single Scattering Albedo (SSA), Real and Imaginary index of Refraction (RRI & IRI respectively), Asymmetry Parameter (ASY) has been utilized for discrimination of aerosols over the study site. Higher mean values of AOD and AE were found in winter and spring season as (0.86 ± 0.38, 0.85 ± 0.32) and (1.06 ± 0.36, 1.19 ± 0.21), while lower values (0.75 ± 0.33, 0.75 ± 0.33) and (0.97 ± 0.22, 0.85 ± 0.17) for summer and autumn season respectively, representing mixed anthropogenic aerosols over the site. Three main types of aerosol were reported in this study: Mixed Carbonaceous (MC), Biomass Residuals (BR), and coarse mode local and transported Dust Particles (DP). Various aerosol parameters and their inter-relationship were investigated in detail to analyze the dominant aerosol type and its seasonal variations. The EAE and AAE values ranged from (0.10–1.77 and 0.00–1.70 respectively), could mainly be attributed towards MC aerosols. Real and Imaginary parts of Index (RRI & IRI) were recorded in the range from (1.33–1.60 and 0–0.010) respectively. Similarly, the range for SSA and ASY was found as (0.79–0.99 and 0.43–0.78) respectively. Back-trajectories using Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model revealed transportation of air masses from Mongolian deserts, Gobi desert, and other neighboring regions (i.e. Russia and Kazakhstan).

Новый вид для Монголии и новые находки сосудистых растений из Джунгарской Гоби

A record of Silene alexandrae B. Keller converts it to a new species for Mongolia. S. alexandrae was found on the Khavtag Mountain ranges in Dzungarian Gobi region. Data about previous records of this species in Mongolia are discussed and rejected. Characters distinguishing Silene alexandrae from close species S. altaica Pers. are given. We noted also new distribution points of fve taxa: Cortusa matthioli L. subsp. altaica (Losinsk.) Korobkov, Ranunculus turczaninovii (Luferov) Vorosch., Rubus saxatilis L., Polygonatum odoratum (Mill.) Druce and Pyrola rotundifolia L. – in Dzungarian Gobi region of Mongolia.

Construction of a conceptual model for confined groundwater flow in the Gunii Khooloi Basin, Southern Gobi Region, Mongolia

Groundwater plays a vital role in the arid Southern Gobi Region (SGR) of Mongolia. It is the only source of water supply and is largely utilized for mining operations, such as those at Oyu Tolgoi Mine. The area is expected to face severe water shortages for mining and drinking water, which may be related to changes in groundwater recharge due to climate change. Understanding the geochemical evolution of groundwater and recharge mechanisms is thus paramount for water resource management. In this study, for the first time, chemical and isotopic approaches have been used to characterize the groundwater origin and its associated recharge processes in the Gunii Khooloi basin, which is located in the SGR. Shallow groundwater is mainly characterized by Na(HCO3) and NaCl type; however, Gunii Khooloi aquifer is classified as NaCl type with high electrical conductivity. The stable isotope composition of the water in the deep Cretaceous confined aquifer shows depletion in 2H and 18O relative to modern rainfall and the Quaternary shallow aquifer, which indicates a weak interaction between the two aquifers. Modern groundwater was identified in the shallow streambed aquifer, probably due to the direct infiltration of rainfall. On the other hand, 14C ages in the deep groundwater range from 2,800 to 33,500 years, which suggests that this is paleowater that was recharged during the glacial age. The results indicate that there is a need for strategic groundwater management in the Gunii Khooloi basin.

Effectiveness of hole plate-type sand barriers in reducing aeolian sediment flux: Evaluation of effect of hole size

Abstract Hole plate-type sand barriers can effectively control wind-sand disasters along the railways running through the windy Gobi desert region, and the hole diameter of hole plate is the key geometric parameter influencing their protective effect. To determine the effect of hole diameter on the wind-sand flow field of hole plate-type sand barriers, in this study, numerical simulations and wind tunnel tests were conducted on hole plate-type sand barriers with different hole diameters (1.03 cm, 2.06 cm, and 4.12 cm) but the same porosity (30%). The results showed that the protective effect of sand barriers presented regular changes with the change in hole diameter. Regarding the flow field, an increase in hole diameter increased the wind penetration rate of sand barrier, decreased the area of acceleration zone above the sand barrier, shortened the length of vortex zone on the leeward side, and lowered the degree of wind velocity reduction by sand barrier. Regarding the distribution of sand deposit, an increase in hole diameter decreased the sand deposits on the windward side of sand barrier, increased the sand deposits on the leeward side, and overall shifted the sand deposit on the leeward side towards the downwind direction. Moreover, hole diameter and sand interception of sand barrier showed a negative correlation. The sand interception of sand barrier with the smallest hole diameter (1.03 cm) exceeded the sand interceptions of the other two sand barriers by 5.41% and 13.43%, respectively. At different heights, the sand barrier with a relatively small hole diameter maintained a relatively high sand-retaining efficiency. The advantage was particularly significant within the height range of 0.5–1H. Moreover, the effective protection ranges of the three sand barriers were approximately the same. The effective protection interval approximately ranged from 1H on the windward side to 10H on the leeward side, and the effective protection height was found to be 1H.