Subjects: Geosciences >> Geology submitted time 2024-05-15 Cooperative journals: 《干旱区科学》
Abstract： Human activities lead to the accumulation of a large amount of nitrogen and phosphorus in sediments in rivers. Simultaneously, nitrogen and phosphorus can be affected by environment and re-enter the upper water body, causing secondary pollution of the river water. In this study, laboratory simulation experiments were conducted initially to investigate the release of nitrogen and phosphorus from river sediments in Urumqi City and the surrounding areas in Xinjiang Uygur Autonomous Region of China and determine the factors that influence their release. The results of this study showed significant short-term differences in nitrogen and phosphorus release characteristics from sediments at different sampling points. The proposed secondary kinetics model (i.e., pseudo-second-order kinetics model) better fitted the release process of sediment nitrogen and phosphorus. The release of nitrogen and phosphorus from sediments is a complex process driven by multiple factors, therefore, we tested the influence of three factors (pH, temperature, and disturbance intensity) on the release of nitrogen and phosphorus from sediments in this study. The most amount of nitrate nitrogen (NO3–-N) was released under neutral conditions, while the most significant release of ammonia nitrogen (NH4+-N) occurred under acidic and alkaline conditions. The release of nitrite nitrogen (NO2–-N) was less affected by pH. The dissolved total phosphorus (DTP) released significantly in the alkaline water environment, while the release of dissolved organic phosphorus (DOP) was more significant in acidic water. The release amount of soluble reactive phosphorus (SRP) increased with an increase in pH. The sediments released nitrogen and phosphorus at higher temperatures, particularly NH4+-N, NO3–-N, and SRP. The highest amount of DOP was released at 15.0°C. An increase in disturbance intensity exacerbated the release of nitrogen and phosphorus from sediments. NH4+-N, DTP, and SRP levels increased linearly with the intensity of disturbance, while NO3–-N and NO2–-N were more stable. This study provides valuable information for protecting and restoring the water environment in arid areas and has significant practical reference value.
Subjects: Geosciences >> Atmospheric Sciences submitted time 2024-05-15 Cooperative journals: 《干旱区科学》
Abstract： The desert-oasis transition zone (DOTZ) serves as a buffer area between the desert and oasis. Understanding its wind field characteristics is of great significance for the prevention and control of aeolian disasters in the oasis. In this study, we used meteorological data during 2013–2019 from the portable meteorological stations at five sites (site A on the edge of the oasis, sites B, C, and D in the DOTZ, and site O in the desert) in Dunhuang, China to analyze the near-surface wind field characteristics and their causes, as well as to reveal the key role of the DOTZ in oasis protection. The results showed that the mean wind speed, frequency of sand-driving wind, and directional variability of wind decreased from west to east within the DOTZ, and wind speed was significantly affected by air temperature. The terrain influenced the prevailing winds in the region, mainly from northeast and southwest. Only some areas adjacent to the oasis were controlled by southeasterly wind. This indicated that the near-surface wind field characteristics of the DOTZ were caused by the combined effects of local terrain and surface hydrothermal difference. At site D, the annual drift potential (DP) was 24.95 vector units (VU), indicating a low wind energy environment, and the resultant drift direction (RDD) showed obvious seasonal differences. Additionally, the DOTZ played an important buffering role between the desert and oasis. Compared with the desert, the mean wind speed in the oasis decreased by 64.98%, and the prevailing wind direction was more concentrated. The results of this study will be useful in interpreting the aeolian activity of the DOTZ in Dunhuang.
Subjects: Geosciences >> Geology submitted time 2024-05-15 Cooperative journals: 《干旱区科学》
Abstract： The southern margin of the Gurbantunggut Desert, China, is characterized by alternating layers of aeolian and alluvial deposits. Investigating the characteristics of arenaceous sediment in this area is of significant importance for understanding the interactive processes of wind and water forces, as well as the provenance of sediment. However, there are relatively few investigations on the characteristics of such sediment at present. In this study, we researched three aeolian-alluvial interactive stratigraphic profiles and different types of surface sediment on the desert-oasis transitional zone of southern margin of the Gurbantunggut Desert. Based on the optically stimulated luminescence (OSL) dating of aeolian sand and analyses of quartz sand grain size and surface micro-texture, we explored the aeolian-alluvial environmental change at southern margin of the desert in Holocene, as well as the provenance of sediment. The results indicated that the grain size characteristics of different types of sediment in the stratigraphic profiles were similar to those of modern dune sand, interdune sand, muddy desert surface soil, and riverbed sand. Their frequency curves were unimodal or bimodal, and cumulative probability curves were two-segment or three-segment, mainly composed of suspension load and saltation load. The quartz sand in the sediment at southern margin of the desert had undergone alternating transformation of various exogenic forces, with short transportation distance and time, and sedimentary environment was relatively humid. In Holocene, southern margin of the desert primarily featured braided river deposits, and during intermittent period of river activity, there were also aeolian deposits such as sand sheet deposits, stabilized dune deposits, and mobile dune deposits. The provenance for Holocene alluvial deposits at southern margin of the desert remains relatively constant, with the debris of the Tianshan Mountains being the primary provenance. Aeolian sand is mainly near-source recharge, which is formed by in situ deposition of fluvial or lacustrine materials in southern margin of the desert transported by wind erosion, and its provenance was still the weathered debris of the Tianshan Mountains. In addition, the sand in interior of the desert may be transported by northwest wind in desert-scale, thus affecting the development of dunes in southern margin of the desert. The results of this study provide a reference for understanding the composition and provenance changes of desert sand in the context of global climate change.
Subjects: Geosciences >> Geography submitted time 2024-05-15 Cooperative journals: 《干旱区科学》
Abstract： Ecological stability is a core issue in ecological research and holds significant implications for humanity. The increased frequency and intensity of drought and wet climate events resulting from climate change pose a major threat to global ecological stability. Variations in stability among different ecosystems have been confirmed, but it remains unclear whether there are differences in stability within the same terrestrial vegetation ecosystem under the influence of climate events in different directions and intensities. China's grassland ecosystem includes most grassland types and is a good choice for studying this issue. This study used the Standardized Precipitation Evapotranspiration Index-12 (SPEI-12) to identify the directions and intensities of different types of climate events, and based on Normalized Difference Vegetation Index (NDVI), calculated the resistance and resilience of different grassland types for 30 consecutive years from 1990 to 2019 (resistance and resilience are important indicators to measure stability). Based on a traditional regression model, standardized methods were integrated to analyze the impacts of the intensity and duration of drought and wet events on vegetation stability. The results showed that meadow steppe exhibited the highest stability, while alpine steppe and desert steppe had the lowest overall stability. The stability of typical steppe, alpine meadow, temperate meadow was at an intermediate level. Regarding the impact of the duration and intensity of climate events on vegetation ecosystem stability for the same grassland type, the resilience of desert steppe during drought was mainly affected by the duration. In contrast, the impact of intensity was not significant. However, alpine steppe was mainly affected by intensity in wet environments, and duration had no significant impact. Our conclusions can provide decision support for the future grassland ecosystem governance.
Subjects: Geosciences >> Geography submitted time 2024-05-15 Cooperative journals: 《干旱区科学》
Abstract： Weihe River basin is of great significance to analyze the changes of land use pattern and landscape ecological risk and to improve the ecological basis of regional development. Based on land use data of the Weihe River basin in 2000, 2010, and 2020, with the support of Aeronautical Reconnaissance Coverage Geographic Information System (ArcGIS), GeoDa, and other technologies, this study analyzed the spatial-temporal characteristics and driving factors of land use pattern and landscape ecological risk. Results showed that land use structure of the Weihe River basin has changed significantly, with the decrease of cropland and the increase of forest land and construction land. In the past 20 a, cropland has decreased by 7347.70 km2, and cropland was mainly converted into forest land, grassland, and construction land. The fragmentation and dispersion of ecological landscape pattern in the Weihe River basin were improved, and land use pattern became more concentrated. Meanwhile, landscape ecological risk of the Weihe River basin has been improved. Severe landscape ecological risk area decreased by 19,177.87 km2, high landscape ecological risk area decreased by 3904.35 km2, and moderate and low landscape ecological risk areas continued to increase. It is worth noting that landscape ecological risks in the upper reaches of the Weihe River basin are still relatively serious, especially in the contiguous areas of high ecological risk, such as Tianshui, Pingliang, Dingxi areas and some areas of Ningxia Hui Autonomous Region. Landscape ecological risk showed obvious spatial dependence, and high ecological risk area was concentrated. Among the driving factors, population density, precipitation, normalized difference vegetation index (NDVI), and their interactions are the most important factors affecting the landscape ecological risk of the Weihe River basin. The findings significantly contribute to our understanding of the ecological dynamics in the Weihe River basin, providing crucial insights for sustainable management in the region.
Subjects: Geosciences >> Geography submitted time 2024-04-29 Cooperative journals: 《干旱区研究》
Abstract： The Keluke Lake-Tuosu Lake Nature Reserve is a key wetland that represents the only large-scale stop-over site and an important habitat for migratory birds in the desert area of the Qaidam Basin, China. These birds migrate along the Central Asian-Indian migration route, which is part of the global migratory bird network. Most birds in the reserve are migratory birds. In this study, their diversity was investigated using a sample line survey and fixed points. A total of 18 families, 43 genera, and 138 species of birds were recorded, with 10 and 24 of the latter being listed as class I and class II wild species, respectively, which are protected nationwide in China. From 2019 to 2021, the number of bird species increased by 37%, with summer visitors and traveling birds increasing by 23.53% and 88.24%, respectively, which corresponded to their numbers increasing by 2.03 and 7.95 times. Summer visitors and traveling birds are important members of the bird community. The values of the Shannon-Wiener index of richness and the Pielou index of evenness for the bird community increased from 2.45 and 0.46 in 2019 to 3.64 and 0.63 in 2021, respectively. Bird diversity was shown to be high in the Keluke Lake-Tuosu Lake Nature Reserve, with the populations of black-necked cranes and red-crested pochards reaching the 1% population tandard established for Ramsar sites. Therefore, an application for the designation of the reserve as a Ramsar site needs to be made as soon as possible. Some individuals belonging to seven bird species, including red-crested pochard and common merganser among others, survived through winter in the Keluke Lake-Tuosu Lake Nature Reserve. Long-term bird diversity studies should be conducted in this area.
Subjects: Geosciences >> Geography submitted time 2024-04-29 Cooperative journals: 《干旱区研究》
SU Canxia
CHU Wenwen
BAHATIBIEKE Pielizhati
JIANG Xiaoheng
CHEN Yanqiu
HUANG Wenpu
MA Chi
CHU Hongjun
Abstract： Castor fiber birulai is primarily distributed in the Ulungu river basin in China. Therefore, investigating the potential distribution of suitable regions is crucial for the conservation of C. f. birulai. A total of 97 distribution sites of C. f. birulai and 28 environmental factors collected from 2021 to 2022 were used to predict the distribution of suitable habitat regions for this species under different climatic scenarios using the MaxEnt model. Results showed that the distribution of suitable habitats was mainly affected by the distance from major roads (0.1–1 km), distance from water channel (within 100 m), landcover type (river, wetland, and forest), altitude (approximately 1000 m), and the standard deviation factor of seasonal temperature change (above 1500). In the 2050s (2041–2060, ssp585 climate scenario) and 2070s (2061–2080, ssp126 climate scenario), the high suitability area was the same or slightly increased compared with the current situation, and the area of suitable habitat, which decreased in the two future climate scenarios, was the same. The results of this study can provide a reference point for the protection and management of C. f. birulai under climate changes.
Subjects: Geosciences >> Geography submitted time 2024-04-29 Cooperative journals: 《干旱区研究》
Abstract： Land use changes have an important impact on carbon stock changes in terrestrial ecosystems, and studying carbon stock changes in terrestrial ecosystems under different development scenarios is conducive to the optimization of spatial layout and coordination of the relationship between land use and ecological environmental protection. In this study, the PLUS and InVEST models were combined, and the characteristics of land use changes in Urumqi from 2000 to 2020 were analyzed using data from multiple drivers to predict and simulate the land carbon stock under the natural development scenario, ecological protection priority scenario, and cropland protection priority scenario in 2030. Results show that from 2000 to 2020, the quantity of forest land, water area, construction area, and unused land increases, whereas the area of arable land and grassland decreases. In 2030, the natural development scenario continues the previous development pattern, and the increase in the area of construction land is 18.29%. Under the ecological protection priority scenario, the expansion rate of construction land is effectively controlled, and the increase has slowed down to 4.73%. The area of arable land under the priority arable land protection scenario is 171 km2 more than under the natural development scenario, and the effect of cultivated land conservation is significant. From 2000 to 2020, and carbon stocks decrease by a total of 8.5×106 t. The total carbon stock in 2030 under the natural growth scenario decreases by 4.065×106 t compared to 2020. the ecological protection priority scenario is 7.519×105 t higher than the natural growth scenario. the cropland protection priority scenario is 1.979×106 t lower than the natural growth scenario.Therefore, in the future development plan of Urumqi City, the responsibility of protecting arable land should be implemented, and the expansion of construction land to high-carbon-density land such as forest land, grassland, and arable land should be controlled. Furthermore, the land use layout should be optimized to improve the level of regional carbon stock.
Subjects: Geosciences >> Geography submitted time 2024-04-29 Cooperative journals: 《干旱区研究》
Abstract： As an important energy production and supply base in China, Xinjiang plays a pivotal role in the deli#2;cate balance between economic development and carbon emissions. Ensuring a harmonious coordination between these factors is essential to achieve sustainable economic growth and meet goals related to energy conservation and emission reduction. This paper measures and analyzes the spatiotemporal characteristics of energy consumption carbon emissions in Xinjiang from 2000 to 2020 using spatial autocorrelation based on the data obtained from Xinjiang Statistical Yearbook. Results indicate that the total carbon emission intensity from energy consump#2;tion in Xinjiang shows an increasing trend every year during the study period. Nevertheless, the overall trend reveals a reduction in the intensity of carbon emissions. The spatial distribution of carbon emission intensity shows that the eastern slope of Tianshan Mountain has a high carbon emission intensity, whereas the northern edge of Junggar, the northern slope of Tianshan Mountain, and the northern slope of Kunlun Mountain has a low carbon emission intensity. These regions exhibit evident clustering characteristics. Considering global warming and carbon emission reduction, Xinjiang must work toward achieving the goals of“carbon peak and“carbon neutrality”while promoting high-quality socioeconomic development in the area through the implementation of a multienergy, complementary green energy network
Subjects: Geosciences >> Geography submitted time 2024-04-29 Cooperative journals: 《干旱区研究》
Abstract： This study aimed to determine whether systematic development and functional traits affect the changes in flowering phenology across woody plants in the Xinjiang Uygur Autonomous Region. Thus, in this study, a botanical garden or park in Urumqi, Yining, and Kashgar was selected as the research object, and then the flowering phenological traits of 120 woody species as well as plant functional traits were observed and collected. The systematic development signals and a generalized least squares model of systematic development were used to study phenological conservation and the impact of plant functional traits on flowering phenology. Results show that the flowering phenology of woody plants was mainly concentrated from March 31 to April 20, with a flowering duration of 13.03 ± 0.38 days. Trees, fleshy fruit, colored flowers, and wind-borne plants have earlier flowering phenology than shrubs, non-fleshy fruit, non-colored flowers, and insect-borne plants, respectively. (2) The phylogenetic signals (Pagel’s λ) of three flowering phenological traits ranged from 0.67 to 0.74, indicating that phylogenetic development constrained the flowering phenology of woody species. (3) Fruit type, flower color, and pollination mode were the main functional traits driving changes in flowering phenology, with a contribution rate of 17.4%–31.6%. The results of this study indicate that systematic development and functional traits affect the changes in flowering phenology across woody plants, which has deepened the phenological theory and is of great importance for elucidating the mechanism of biodiversity maintenance and insect–plant relationships in arid areas.
Subjects: Geosciences >> Geography submitted time 2024-04-29 Cooperative journals: 《干旱区研究》
Abstract： This study is based on the integrated valuation of ecosystem services and tradeoffs model, which quantifies the supply and demand of ecosystem services. This model uses root-mean-square deviation to quantify the intensity of tradeoffs in ecosystem services and analyze the driving factors of tradeoff intensity using a structural equation model. Results show that from 2000 to 2020, the tradeoff intensity of water yield (WY) and soil conservation (SC), as well as WY and carbon sequestration (CS) supply, increased. However, the demand coordination intensity of WY and SC services, as well as WY and CS services, decreased. Except for WY services, which had a supply–demand tradeoff intensity greater than 0 in 2020, the supply–demand tradeoff intensity for WY, SC, and CS services was less than zero from 2000 to 2020. The tradeoff and synergy of ecosystem services are primarily influenced by natural factors. Evapotranspiration has a positive effect on the tradeoff between water production and SC services, as well as on the tradeoff between supply and demand for water production and CS services. However, it has a restraining effect on the tradeoff between supply and demand for water production services. The proportion of grassland area has a restraining effect on the tradeoff between water production and CS services, as well as on the synergy between water production and SC service demands. In addition, it has a promoting effect on the supply–demand tradeoff of CS services. Precipitation has a restraining effect on the synergy between water production and CS service demands, as well as on the tradeoff between supply and demand for SC services. However, it has a promoting effect on the tradeoff between supply and demand for water production services. Socioeconomic factors have a secondary effect on the tradeoff and synergy of ecosystem services. Population density has a promoting effect on the synergy between water production and soil conservation service demands, whereas it has a restraining effect on the tradeoff between supply and demand for water production services and CS services. Therefore, when developing comprehensive management decisions for river basins, the spatial characteristics and driving factors that contribute to the tradeoff and synergy of ecosystem services must be considered.
Subjects: Geosciences >> Geography submitted time 2024-04-29 Cooperative journals: 《干旱区研究》
Abstract： Root biomass is an important part of the soil ecosystem, however, due to the limitations of measurement techniques and methods, it is impossible to rapidly assess it. The ground penetrating radar (GPR) is an efficient and nondestructive geophysical tool through which root information can be obtained without damaging the soil environment. However, accuracy during the detection and identification of underground roots by GPR is significantly affected by many factors such as soil water content, root roughness, length, and extension direction. In particular, soil water content has an obvious effect on root detection. In this study, in situ root embedding detection experiments were carried out to investigate the influence of soil water content on root detection via GPR. Combined with the changes in wave velocity, amplitude, and the root reflection coefficient of the GPR, the root point identification rate and root point distance root point root mean square error were analyzed under different average soil water content. The results showed that (1) the wave velocity and amplitude of the GPR were important parameters to determine variations in soil water conten during root detection; (2) the GPR’s velocity decreased and the radar amplitude flattened with the increasing soil water content; (3) as the root diameter increased at different soil depths, the GPR’s wave velocity also increased and the GPR’s amplitude tended to be drastic changes; (4) the root point recognition rate and soil water content were negatively correlated (P
Subjects: Geosciences >> Geography submitted time 2024-04-29 Cooperative journals: 《干旱区研究》
Abstract： Five typical vegetation types (i.e., coniferous forests, meadow grasslands, alpine shrubs, alpine meadows, and sparse vegetations of limestone flat) along a vertical belt of the Qilian Mountains were selected to explore the spatial elevational patterns of soil carbon, nitrogen, and phosphorus and their stoichiometric ratios. Results showed that: (1) The contents of total carbon (C), nitrogen (N), and phosphorus (P) at the 0~40 cm depth were 15.33~83.46, 1.63~7.76, and 0.37~0.74 mg·kg-1, respectively. Soil C and N decreased gradually with increasing altitudes, following the order coniferous forests > meadow steppes > alpine shrubs > alpine meadows > sparse vegetations of limestone flat. Soil P in alpine scrubs was significantly higher than that in alpine meadows, but the other three vegetations showed no significant difference. (2) The contents of NH+ 4-N, NO- 3-N and available phosphorus at the 0~40 cm depth were 11.01~14.73, 2.78~12.46, and 4.35~13.57 mg·kg-1, respectively. Ammonium was the main inorganic nitrogen form in all vegetation types. The nitrite content decreased gradually with increasing altitude. The content of soil available phosphorus was higher in sparse vegetations of limestone flats. (3) The ratios of soil C:N, C:P, and N:P at the 0~40 cm depth were 9.52~10.11, 29.89~320.24, and 3.18~29.63, respectively. Soil C:N decreased with elevation. Soil C:P and N:P were significantly lower in the soil of sparse vegetations of the limestone flat than in other vegetations, indicating that carbon and nitrogen were the limiting nutrients in the limestone flat. By contrast, the limestone flat was in a phosphorus-rich state. Elevational variations in soil C, N, and P contents and their stoichiometric ratios reflect the joint control of multiple environmental factors, thereby affecting the biochemical processes of soil C, N, and P.
Subjects: Geosciences >> Geography submitted time 2024-04-29 Cooperative journals: 《干旱区研究》
Abstract： Desert vegetation is an important ecological protection barrier for oasis ecosystems in the Hexi Corridor. Studying the composition of desert vegetation and the spatial distribution of soil nutrients is important to the construction and management of desert-oasis transition zone vegetation. This study is based on several field surveys. Traditional statistical and geostatistical methods were used to investigate the composition of desert vegetation and soil nutrient characteristics in the middle section of the Hexi Corridor and the southern fringe of the Badain Jaran Desert, and their correlation with environmental factors were analyzed. Results indicated that the plant composition in the desert areas of the middle section of the Hexi Corridor and the southwestern fringe of the Badain Jaran Desert was single and had low diversity, with plant species concentrated in a few families. Typical desert plants such as Reaumuria songarica and Nitraria tangutorum were frequently found in the study area. The distribution of herbaceous plants was strongly correlated with the average annual precipitation. In Shandan County, which is located in the southern part of the study area, the biomass of herbaceous plants reached 108.01 g·m−2. Within a certain range of annual precipitation, the biomass of shrubs increased with the increase of precipitation, with the highest value occurring in Suzhou County, near the northern slope of the Qilian Mountains, at 134.03 g·m−2. Increasing precipitation significantly promoted the growth of herbaceous plants. The surface soil had the highest organic carbon, total nitrogen, and total phosphorus contents in the study area, with average values of 2.12, 0.25, and 0.41 g·kg−1, respectively, and higher levels of variability than those in the soil subsurface. In the horizontal direction, the three types of soil nutrients had high variability and weak spatial autocorrelation, with maximum values of 11.22, 1.30, and 0.73 g·kg−1 near Zhangye Oasis. Principal component analysis showed that soil properties and precipitation were the primary factors causing habitat differences in the study area. However, different environmental factors interacted with one another to jointly drive desert vegetation composition and distribution.
Subjects: Geosciences >> Geography submitted time 2024-04-29 Cooperative journals: 《干旱区研究》
Abstract： Exploring the characteristics of soil properties, fungal communities, and their driving factors in different microgeomorphic units in arid gravel desert areas is important for the study of fungal community construction mechanisms and practical guidance for targeted ecological damage restoration strategies. In this paper, the changes in soil physicochemical properties, fungal α diversity, and community composition of four microgeomorphic units (wind erosion residual hills, gravel desert Gobi, river valley, and wind sand land) in an arid gravel desert area were compared. The main factors affecting soil fungal communities in different microgeomorphological units in gravel desert areas were explored by combining plant characteristics and micrometeorological factors. Results showed that the soil in the arid gravel desert area was dominated by sandy soil, and wind sand land had the largest sandy content and the smallest clay content, which was contrary to the soil mechanical composition of the river valley. No significant difference in soil bulk density and organic matter content was found between the river valley and the gravel desert Gobi, but their soil bulk density and organic matter content were significantly higher than those of the other two microgeomorphic units. However, the soluble salt content of the river valley was 21.4%, which was significantly lower than that in other microgeomorphic units, but the soil water content was significantly higher by 39.3%. Except for the contents of available N, available K and available P in the gravel desert Gobi and wind erosion residual hills, no significant difference in the available nutrients was found in other microgeomorphological units. In addition, the α diversity of soil fungi, Shannon-Wiener index, Pieloue inde, and Simpson index all showed a significant decrease in wind sand land, whereas no significant difference in other microgeomorphological units was found. However, the Chao1 index has no significant difference. At the phylum level, the dominant fungi phyla were Ascomycota and Basidiomycota in different microgeomorphicregions. Ascomycota has the largest dominance in the gravel desert Gobi and wind erosion residual hills, and Basidiomycota has the largest proportion in the river valley. At the genera level, Neocamarosporium and Subramaniu in the Wind erosion residual hill, Preussia and Neocamarosporium in the gravel desert Gobi, Aspergillus and Alternaria in the river valley, and Trichophaeopsis and Neocamarosporium in the wind sand land were the dominant genera of soil fungal communities in each geomorphic unit. Soil water content, organic matter, available N, and soluble salts were the common key factors affecting the changes in soil fungal community structure in different microgeomorphic units in an arid gravel desert area. Furthermore, the soil mechanical composition in wind sand land, surface temperature and light radiation intensity of wind erosion residual hills, surface wind speed of gravel desert Gobi, and surface vegetation biomass of river valley were the differentiated ecological factors affecting soil fungal community in each geomorphic unit.
Subjects: Geosciences >> Geography submitted time 2024-04-29 Cooperative journals: 《干旱区研究》
Abstract： Mining activities have strongly changed the characteristics of the regional hydrological cycle and have a significant impact on the chemical characteristics of groundwater. Revealing the evolutionary characteristics of the groundwater system under the influence of coal mine development can provide theoretical support for ecological environment protection and sustainable development in coal mine areas. In this paper, taking the Yimin Basin in Inner Mongolia as an example, based on hydrogeological investigation combined with the groundwater flow system theory, Piper three-line diagram, Gibbs diagram, ion proportional coefficient, mineral saturation index, and other analysis methods, the characteristics of groundwater chemical changes under the interference of coal mining activities were explored. Results indicate that the overall water environment in the study area is weakly alkaline, and the significant influence and noninfluence zones exceed the detection indexes in different degrees. Coal mining in the basin has accelerated the rate of regional hydrological cycle, causing the water quality in the significant impact zone to evolve toward desalination. The development of open-pit coal mining has opened up the previously closed groundwater system, and a series of water-rock interactions stimulated by the oxidation of sulfur- containing coal and sulfurous iron ore and acid production primarily cause the changes in the chemical characteristics of the regional groundwater. The hydrochemistry of groundwater in the basin is affected by evaporation, concentration and water- rock interactions. Along the flow direction of groundwater, the hydrochemical type in the significantly affected area changes from HCO3-Ca·Na type to HCO3-Ca, and the concentrations of TDS and Cl- show a downward trend. In the nonaffected zone, the hydrochemical type changed from HCO3-Ca·Na to Cl-Ca·Mg, and the concentrations of TDS and Cl- showed an upward trend.
Subjects: Geosciences >> Geography submitted time 2024-04-29 Cooperative journals: 《干旱区研究》
Abstract： By using stable isotope data of atmospheric precipitation from September 2018 to May 2020 in the Taxkorgan River Basin Valley and meteorological data such as temperature, precipitation, and relative humidity from representative weather stations within the valley, this study analyzed the variation in δ18O, δ2H, and deuterium excess (d-excess) of precipitation. The influencing factors were explored, and the water vapor transport pathways of atmospheric precipitation in the valley were traced and analyzed using the hybrid single- particle Lagrangian integrated trajectory model (HYSPLIT). Results show that the δ2H and δ18O values of precipitation gen#2;erally present a seasonal pattern of enrichment in summer and depletion in winter, showing a significant tempera#2;ture effect (1.33‰·℃- 1), but no significant precipitation effect was observed. The local meteoric water line is δ2H=7.63δ18O-3.55, which shows distinct arid climate characteristics. The HYSPLIT simulation results indicate that the water vapor of precipitation in the study basin is mainly influenced by the westerly circulation and local water vapor recycling, with local water vapor evaporation accounting for 54.09% in the summer half-year and the long-distance transport of the western route accounting for 45.53% in the winter half-year. Water vapor from the Indian Ocean in August can bypass the Tibetan Plateau and reach the study area. These findings can provide a reference basis for water resource management and climate response in the Taxkorgan River Basin Valley.
Subjects: Geosciences >> Geography submitted time 2024-04-29 Cooperative journals: 《干旱区研究》
Abstract： Winter drought is a main factor hindering winter livestock production in Inner Mongolia. Thus, quanti#2;tative characterization of its spatiotemporal changes and development patterns is of great significance for disaster prevention and reduction and for ensuring the healthy development of agriculture and animal husbandry. Using ERA5-Land reanalysis meteorological data from the winter of 1980 to 2021 (October to March of the following year), the standardized precipitation evapotranspiration index (SPEI) was calculated at monthly and semi-annual scales. Trend analysis, spatiotemporal hotspot analysis, and other methods were used to analyze the winter drought evolution characteristics of the entire Inner Mongolia region and the five main vegetation types. Results show that in the past 40 years, the overall SPEI in Inner Mongolia has shown an increasing trend in winter, andaridification varies among different vegetation and months, with a few vegetation and months tending toward hu#2;midification. The change patterns in Inner Mongolia mainly include three types: oscillating hot spots, oscillating cold spots, and undetected patterns. From a seasonal perspective, hotspots are primarily distributed in most areas of western Inner Mongolia, as well as in Xing’an League and Tongliao City in the east. On a monthly scale, hot#2;spots often appear in the central and western regions of Inner Mongolia. With regard to drought frequency and fre#2;quency statistics, mild drought events have the highest frequency, whereas winter drought events occur more fre#2;quently and seriously in desert grasslands and neighboring desert areas.
Subjects: Geosciences >> Geography submitted time 2024-04-29 Cooperative journals: 《干旱区研究》
Abstract： Persistent cold air pools (PCAPs) in valley cities lead to the prolonged accumulation of air pollutants,thereby affecting the lives and health of residents. In this study, sounding data and daily air quality data from January 2013 to November 2023 were used to calculate and statistically analyze the characteristics of PCAPs occurrences in the Lanzhou Valley. In addition, the impact of PCAPs intensity on changes in pollutant concentrations was explored, and variations in pollutant concentrations during PCAPs were analyzed and compared with concurrent dust aerosol pollution. Results indicate that from 2013 to 2023, 59 PCAPs occurred, lasting cumulative 197days. During PCAPs, valley heat deficit and PM2.5 concentrations were 4.43 J·m−2 and 52.14 μg·m−3 higher, respectively, compared with non-PCAPs. The air quality index (AQI), SO2 concentration, NO2 concentration, CO concentration, and PM10 concentration increased by 70.37%, 144.3%, 84.3%, 156%, and 73.15%, respectively, whereas O3 concentration decreased by 60.89% during PCAPs. In PCAPs without dust aerosols, the average PM2.5:PM10 ratiowas 0.58, whereas in PCAPs with dust aerosols, the average ratio was 0.31. During PCAPs with concurrent dustaerosols, PM2.5 concentration, PM10 concentration, AQI, and O3 concentration increased by 18.33% , 133.03% ,84.44%, and 8.5%, respectively. However, SO2 and CO concentrations decreased by 17.54% and 17.88%, respectively. These findings can serve as a reference for atmospheric pollution prevention and management strategies in the Lanzhou region.
Subjects: Geosciences >> Geography submitted time 2024-04-29 Cooperative journals: 《干旱区研究》
Abstract： The Tibetan Plateau has a unique climate, complex topography, and few meteorological observation stations, which makes it difficult to observe and simulate its regional climate and water cycle processes. Using the regional climate models RegCM and WRF, the spatial and temporal distribution of the climate in this region from 1989 to 2008 was systematically analyzed, and the simulation capability of the RegCM and WRF models was investigated at 10, 25, and 50 km horizontal resolutions in the Tibetan Plateau. Results show that the trend of annual average temperature simulated by both models at 10 km horizontal resolution is 1.60-2.122 ℃ lower than the multiyear average temperature simulation at 25 and 50 km horizontal resolution. With increasing horizontal resolution, the simulation biases of annual and seasonal temperatures simulated by the WRF model decrease, and the cold bias of temperature in the central and western parts of the Tibetan Plateau improves. The simulated tem#2;perature in the RegCM model at a 10 km horizontal resolution has the lowest error, and it is significantly better for simulating the spatial distribution of temperature in the Tibetan Plateau. The correlation between the simulat#2;ed temperature of both models in different seasons and the observation data has been improved. In the precipita#2;tion simulation, the WRF model at a horizontal resolution of 25 km has the best correlation with the observed da#2;ta but has the largest error. With the increase of horizontal resolution, the overestimation of precipitation in the southeastern and southern Tibetan Plateau by the WRF model has been significantly improved, and the annual precipitation simulated by the RegCM model gradually approaches the measured values (the overestimation de#2;creases from about 2.73 times to 1.77 times). However, the overall overestimation of precipitation by both models still exists. In the simulation of the five major river sources on the Tibetan Plateau, with increasing horizontal spa#2;tial resolution, the WRF model reduces the biases of the air temperature in the source region of the Mekong river and Salween River, whereas the RegCM model reduces the biases of the air temperature in the source region of the Brahmaputra River and Mekong river. The largest reduction in precipitation bias was achieved in the Brahmaputra River source region at 10 km horizontal resolution by the WRF and RegCM models. This study can lay the foundation for understanding the impact of climate change on the water cycle process in the Tibetan Plateau.
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