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.
Subjects: Geosciences >> Geography submitted time 2024-04-29 Cooperative journals: 《干旱区研究》
Abstract： Based on data obtained from the Micro Rain Radar (MRR), OTT-PARSIVEL laser raindrop spectrometer, and Rain Gauge (RG) at Zeku Station, the applicability of the MRR in the plateau region was compared and examined for a precipitation weather process on September 17, 2021. The vertical variation characteristics of the MRR observation parameters and raindrop spectrum were investigated at different rain rates. Results show that the observed cumulative rainfall results of the MRR were consistent with those of the raindrop spectrometer and RG, and the MRR 200 m rain rate was highly associated with the raindrop spectrometer inversion value. At various levels of rainfall intensity, differences were found in the vertical distribution of precipitation parameters. Reflectivity, rain rate and liquid water content were affected by evaporation, and they fluctuated from high to low levels in the Ⅰ stage of rain. The evaporation effect was weakened, and the peak height of each microphysical quantity was lower in the II stage of rain. The increase in particle diameter was due to the intensification of collision and coalescence, and the microphysical quantities increased with the decrease in height in the III stage of rain. Precipitation was dominated by small particles, and the raindrop number concentration contribution of small particles at each height layer was the largest. The contribution rate of 1000-4000 m small particles to the rain rate exceeded 90%, and the contribution rate of medium particles below 1000 m to the rain rate increased with the decrease of height. The contribution rate of large particles to the rain rate in the upper layer was greater than that in the lower layer.
Subjects: Geosciences >> Geography submitted time 2024-04-15 Cooperative journals: 《干旱区科学》
Abstract： Arid areas with low precipitation and sparse vegetation typically yield compact urban pattern, and drought directly impacts urban site selection, growth processes, and future scenarios. Spatial simulation and projection based on cellular automata (CA) models is important to achieve sustainable urban development in arid areas. We developed a new CA model using bat algorithm (BA) named bat algorithm-probability-of-occurrence-cellular automata (BA-POO-CA) model by considering drought constraint to accurately delineate urban growth patterns and project future scenarios of Urumqi City and its surrounding areas, located in Xinjiang Uygur Autonomous Region, China. We calibrated the BA-POO-CA model for the drought-prone study area with 2000 and 2010 data and validated the model with 2010 and 2020 data, and finally projected its urban scenarios in 2030. The results showed that BA-POO-CA model yielded overall accuracy of 97.70% and figure-of-merits (FOMs) of 35.50% in 2010, and 97.70% and 26.70% in 2020, respectively. The inclusion of drought intensity factor improved the performance of BA-POO-CA model in terms of FOMs, with increases of 5.50% in 2010 and 7.90% in 2020 than the model excluding drought intensity factor. This suggested that the urban growth of Urumqi City was affected by drought, and therefore taking drought intensity factor into account would contribute to simulation accuracy. The BA-POO-CA model including drought intensity factor was used to project two possible scenarios (i.e., business-as-usual (BAU) scenario and ecological scenario) in 2030. In the BAU scenario, the urban growth dominated mainly in urban fringe areas, especially in the northern part of Toutunhe District, Xinshi District, and Midong District. Using exceptional and extreme drought areas as a spatial constraint, the urban growth was mainly concentrated in the "main urban areas-Changji-Hutubi" corridor urban pattern in the ecological scenario. The results of this research can help to adjust urban planning and development policies. Our model is readily applicable to simulating urban growth and future scenarios in global arid areas such as Northwest China and Africa.
Subjects: Geosciences >> Geography submitted time 2024-04-01 Cooperative journals: 《干旱区地理》
Abstract：研判城市绿色发展效率及其优化路径，是推进黄河流域高质量发展的关键环节，亦是践行“碳达峰、碳中和”战略目标的重要方略。利用EBM-GML模型测算2005—2020年黄河流域58个城市的绿色发展效率，依次采用HP滤波分析、时空交互方法勾勒其演化特征，并对其多元提升路径进行定量识别。结果表明：（1）研究期内黄河流域城市绿色发展效率呈增长态势，由2005年的0.509提升至2020年的0.651，相继经历“波动—提升—共生”3个阶段，区域内部非均衡性特征显著。（2）黄河流域城市绿色发展效率局部空间结构具有良好的稳健性，空间移动方向波动性较强，城际空间协作程度大于空间竞争。（3）模糊集定性比较分析（fsQCA）结果表明，存在经济驱动型、双元驱动型、资源整合型、全面提升型4条优化路径，经济发展、科技创新等因素为必要条件。
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