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 b...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.展开更多
Climate change and increasing anthropogenic activities,such as over-exploitation of groundwater,are exerting unavoidable stress on groundwater resources.This study investigated the spatio-temporal variation of depth t...Climate change and increasing anthropogenic activities,such as over-exploitation of groundwater,are exerting unavoidable stress on groundwater resources.This study investigated the spatio-temporal variation of depth to groundwater level(DGWL)and the impacts of climatic(precipitation,maximum temperature,and minimum temperature)and anthropogenic(gross district product(GDP),population,and net irrigated area(NIA))variables on DGWL during 1994-2020.The study considered DGWL in 113 observation wells and piezometers located in arid western plains(Barmer and Jodhpur districts)and semi-arid eastern plains(Jaipur,Ajmer,Dausa,and Tonk districts)of Rajasthan State,India.Statistical methods were employed to examine the annual and seasonal patterns of DGWL,and the generalized additive model(GAM)was used to determine the impacts of climatic and anthropogenic variables on DGWL.During 1994-2020,except for Barmer District,where the mean annual DGWL was almost constant(around 26.50 m),all other districts exhibited increase in DGWL,with Ajmer District experiencing the most increase.The results also revealed that 36 observation wells and piezometers showed a statistically significant annual increasing trend in DGWL and 34 observation wells and piezometers exhibited a statistically significant decreasing trend in DGWL.Similarly,32 observation wells and piezometers showed an statistically significant increasing trend and 37 observation wells and piezometers showed a statistically significant decreasing trend in winter;33 observation wells and piezometers indicated a statistically significant increasing trend and 34 had a statistically significant decreasing trend in post-monsoon;35 observation wells and piezometers exhibited a statistically significant increasing trend and 32 observation wells and piezometers showed a statistically significant decreasing trend in pre-monsoon;and 36 observation wells and piezometers reflected a statistically significant increasing trend and 30 observation wells and piezometers reflected a statistically significant decreasing trend in monsoon.Interestingly,most of the observation wells and piezometers with increasing trends of DGWL were located in Dausa and Jaipur districts.Furthermore,the GAM analysis revealed that climatic variables,such as precipitation,significantly affected DGWL in Barmer District,and DGWL in all other districts was influenced by anthropogenic variables,including GDP,NIA,and population.As a result,stringent regulations should be implemented to curb excessive groundwater extraction,manage agricultural water demand,initiate proactive aquifer recharge programs,and strengthen sustainable management in these water-scarce regions.展开更多
The economy of most rural locations in the semi-arid region of Llano Estacado in the southern United States is predominantly based on agriculture, primarily beef and wheat (Triticum aestivum L.) production. This regio...The economy of most rural locations in the semi-arid region of Llano Estacado in the southern United States is predominantly based on agriculture, primarily beef and wheat (Triticum aestivum L.) production. This region is prone to drought and is projected to experience a drier climate. Droughts that coincide with the critical phenological phases of a crop can be remarkably costly. Although drought cannot be prevented, its losses can be minimized through mitigation measures if it is predicted in advance. Predicting yield loss from an imminent drought is an important need of stakeholders. One way to fulfill this need is using an agricultural drought index, such as the Agricultural Reference Index for Drought (ARID). Being plant physiology-based, ARID can represent drought-yield relationships accurately. This study developed an ARID-based yield model for predicting the drought-induced yield loss for winter wheat in this region by accounting for its phenological phase-specific sensitivity to water stress. The reasonable values of the drought sensitivity coefficients of the yield model indicated that it could reflect the phenomenon of water stress decreasing the winter wheat yields in this region reasonably. The values of the various metrics used to evaluate the model, including Willmott Index (0.86), Nash-Sutcliffe Index (0.61), and percentage error (26), indicated that the yield model performed fairly well at predicting the drought-induced yield loss for winter wheat. The yield model may be useful for predicting the drought-induced yield loss for winter wheat in the study region and scheduling irrigation allocation based on phenological phase-specific drought sensitivity.展开更多
Rainwater harvesting (RWH) systems have been developed to compensate for shortage in the water supply worldwide. Such systems are not very common in arid areas, particularly in the Gulf Region, due to the scarcity of ...Rainwater harvesting (RWH) systems have been developed to compensate for shortage in the water supply worldwide. Such systems are not very common in arid areas, particularly in the Gulf Region, due to the scarcity of rainfall and their reduced efficiency in covering water demand and reducing water consumption rates. In spite of this, RWH systems have the potential to reduce urban flood risks, particularly in densely populated areas. This study aimed to assess the potential use of RWH systems as urban flood mitigation measures in arid areas. Their utility in the retention of stormwater runoff and the reduction of water depth and extent were evaluated. The study was conducted in a residential area in Bahrain that experienced waterlogging after heavy rainfall events. The water demand patterns of housing units were analyzed, and the daily water balance for RWH tanks was evaluated. The effect of the implementation of RWH systems on the flood volume was evaluated with a two-dimensional hydrodynamic model. Flood simulations were conducted in several rainfall scenarios with different probabilities of occurrence. The results showed significant reductions in the flood depth and flood extent, but these effects were highly dependent on the rainfall intensity of the event. RWH systems are effective flood mitigation measures, particularly in urban arid regions short of proper stormwater control infrastructure, and they enhance the resilience of the built environment to urban floods.展开更多
To improve the land surface simulation in the arid and semi-arid areas of northern China, the observational data from two field experiments in Dunhuang and Tongyu are used to optimize the parameters in the land surfac...To improve the land surface simulation in the arid and semi-arid areas of northern China, the observational data from two field experiments in Dunhuang and Tongyu are used to optimize the parameters in the land surface model, BATS, through calibration with the multicriteria method. Sensitivity analysis to the parameters in Dunhuang and Tongyu indicates that different parameters need to be calibrated in two sites with different environmental and climate regimes. Comparison of observed sensible heat flux, latent heat flux, and ground surface temperature with the simulated ones shows the simulations with the optimized parameters have been substantially improved. Especially, the holistic simulations with the calibration of the parameter values are much closer to the observations in the arid region （Dunhuang）, and the energy partition with the calibrated parameters can also be simulated well in the semi-arid region （Tongyu）. Whole results demonstrate that the parameter calibration of the land surface model is important when the model is to be used to investigate the land-air interaction.展开更多
Dealing with the regional land surfaces heat fluxes over inhomogeneous land surfaces in arid and semi-arid areas is an important but not an easy issue. In this study, one parameterization method based on satellite rem...Dealing with the regional land surfaces heat fluxes over inhomogeneous land surfaces in arid and semi-arid areas is an important but not an easy issue. In this study, one parameterization method based on satellite remote sensing and field observations is proposed and tested for deriving the regional land surface heat fluxes over inhomogeneous landscapes. As a case study, the method is applied to the Dunhuang experimental area and the HEIFE (Heihe River Field Experiment, 1988-1994) area. The Dunhuang area is selected as a basic experimental area for the Chinese National Key Programme for Developing Basic Sciences: Research on the Formation Mechanism and Prediction Theory of Severe Climate Disaster in China (G1998040900, 1999-2003). The four scenes of Landsat TM data used in this study are 3 June 2000, 22 August 2000, and 29 January 2001 for the Dunhuang area and 9 July 1991 for the HEIFE area. The regional distributions of land surface variables, vegetation variables, and heat fluxes over inhomogeneous landscapes in arid and semi-arid areas are obtained in this study.展开更多
Climatic characteristics of broadband solarradiation (Rs) in Chinese arid and semi-arid areas are reported in this study. The annual average daily Rs in thearid and semi-arid areas is 16.3 ± 5.77 and 15.3 ± ...Climatic characteristics of broadband solarradiation (Rs) in Chinese arid and semi-arid areas are reported in this study. The annual average daily Rs in thearid and semi-arid areas is 16.3 ± 5.77 and 15.3 ± 5.16 MJm-2 d-1, respectively. The highest value (17.2 ± 5.84 MJm-2 d-1) appears in an arid area at Linze. The lowest valueappears in the semi-arid area of Ansai. Pronounced seasonal variation of Rs is observed with the highest value insummer and the lowest in winter. The clearness indexshowed similar seasonal pattern at most sites, with theminimum observed in the summer and the highest valuesin winter at both arid and semi-arid areas. The seasonalvariation of the ratio of Rs to its extraterrestrial value Kt inthe arid area is more significant than that observed in thesemi-arid region, and it is caused by the different range ofvariation of water vapor between arid and semi-arid areasThe seasonal fluctuations in Rs and Kt are mainly controlled by the water vapor content in these areas. Theaerosol particles have significant influence on Rs and Kt atstations with higher aerosol burden.展开更多
1. The crux of the environment administration problem is theeconomic development As we Know that the evolution of environment is not only due to Nature itself, but al-so to human being particularly. In the course of h...1. The crux of the environment administration problem is theeconomic development As we Know that the evolution of environment is not only due to Nature itself, but al-so to human being particularly. In the course of history, the Loess Plateau in China, oncewoody and rich in plants has now become a serious soil-erosion area on which lies thou-展开更多
Participatory irrigation management （PIM） is theoretically assumed to reduce poverty significantly, but its practical experience and challenges are yet researched and documented in Tanzania. The study aimed at asses...Participatory irrigation management （PIM） is theoretically assumed to reduce poverty significantly, but its practical experience and challenges are yet researched and documented in Tanzania. The study aimed at assessing challenges observed during implementation of PIM approach for food security in semi-arid areas of Tanzania. Data were collected through questionnaire, participatory rapid appraisal （PRA） tools, key informants interview, Focus Group Discussion （FGD）, observation and literature review. Data collected from questionnaire were analyzed using SPSS. Data fi＇om other methods were analyzed using content analysis. The study revealed that PIM approach has contribution in improving food security at household level due to involvement of communities in water management activities and decision making, which enhanced availability of irrigation water and increased crop production. However, there were challenges observed during implementation of the approach, including the minimum participation of beneficiaries in decision making during planning and designing stages, which means that inadequate devolution of power among scheme owners, inadequate and lack of transparency on income expenditure in water utilization associations （WUAs）, water conflict among WUAs members, conflict between farmers and livestock keepers and conflict between WUAs and village government leaders regarding training opportunities and status. The rules and regulation of WUAs were not legally recognized by the national courts and few farmers who planted trees around water sources. However, it was realized that some of the mentioned challenges were rectified by farmers themselves and facilitated by government officials. The study recommends that the identified challenges need to be rectified for farmers to realize more on the importance of PIM approach as it was realized in other Asian countries.展开更多
Based on 3 years （2003-05） of the eddy covariance （EC） observations on degraded grassland and cropland surfaces in a semi-arid area of Tongyu （44°25′N, 122°52′E, 184 m a.s.1.）, Northeast China, seaso...Based on 3 years （2003-05） of the eddy covariance （EC） observations on degraded grassland and cropland surfaces in a semi-arid area of Tongyu （44°25′N, 122°52′E, 184 m a.s.1.）, Northeast China, seasonal and annual variations of water, energy and CO2 fluxes have been investigated. The soil moisture in the thin soil layer （at 0.05, 0.10 and 0.20 m） clearly indicates the pronounced annual wet-dry cycle; the annual cycle is divided into the wet （growing season） and dry seasons （non-growing season）. During the growing season （from May to September）, the sensible and latent heat fluxes showed a linear dependence on the global solar radiation. However, in the non-growing season, the latent heat flux was always less than 50 W m^-2, while the available energy was dissipated as sensible, rather than latent heat flux. During the growing season in 2003-05, the daily average sensible and latent heat fluxes were larger on the cropland surface than on the degraded grassland surface. The cropland ecosystem absorbed more CO2 than the degraded grassland ecosystem in the growing season in 2003-05. The total evapotranspiration on the cropland was more than the total precipitation, while the total evapotranspiration on the degraded grassland was almost the same as the total annual precipitation in the growing season. The soil moisture had a good correlation with the rainfall in the growing season. Precipitation in the growing season is an important factor on the water and carbon budget in the semi-arid area.展开更多
The division of arid areas is important in water and land resources management, planning and for a long-term agricultural, economic and social planning. Northwest China （NW） dominates the main arid areas in China. T...The division of arid areas is important in water and land resources management, planning and for a long-term agricultural, economic and social planning. Northwest China （NW） dominates the main arid areas in China. There is thus a need to adopt adequate concepts relative to the scope of arid areas of NW China and identify its climate types and characteristics. In this study, we analyzed climatic data over the last 30 years （1981-2010） from 191 stations in three provinces and three autonomous regions of NW China. The factor-cluster analysis technique （FC）, an objective and automated method was employed to classify the dry/wet climate zones. The traditional methods with predefined thresholds were adopted for providing a comparison with FC. The results showed that the wet/dry climate zones by FC were mainly distributed along mountains, rivers and desert borders. Climate-division boundaries relied heavily on the major terrain features surrounding the grouped stations. It also showed that the climate was dry in the plain sandy areas but relatively wet in the high mountain areas. FC method can reflect the climate characteristics more fully in NW China with varied and complicated topography, and outperform the tradi- tional climate classifications. Arid areas of NW China were defined as four climate types, including five resultant classes in FC classifications. The Qinling and Da Hinggan Mountains were two important boundaries, besides main administrative boundaries. The results also indicated that there are some differences between two traditional clas- sifications. The precipitation moved and fluctuated to an extent, which confirmed that climate change played an important role in the dry/wet climate zoning, and the boundaries of dry/wet climate zones might change and migrate with time. This paper is expected to provide a more in-depth understanding on the climate characteristics in arid areas of NW China, and then contribute to formulate reasonable water and land management planning and agri- cultural production programs.展开更多
Rapid land landscape change has taken place in many arid and semi-arid regions such as the vulnerable ecological area over the last decade. In this paper, we quantified land landscape change of Yulin in this area betw...Rapid land landscape change has taken place in many arid and semi-arid regions such as the vulnerable ecological area over the last decade. In this paper, we quantified land landscape change of Yulin in this area between 1985 and 2000 using remote sensing and GIS. It was found that fallow landscape decreased by 125,148 hm^2 while grassland and woodland increased by 107,975 hm^2 and 17,157 hm^2, respectively. The major factors responsible for these changes are identified as the change in the government policy on preserving the environment, continued growth in mining, and urbanization. The efforts in restoring the deteriorated ecosystem have reaped certain benefits in reducing the spatial extent of sandy land through replacement by non-irrigated farmland, woodland and grassland. On the other hand, continued expansion of mining industry and urbanization has exerted adverse impacts on the land landscape. At present regional economic development conflicts directly with the protection of the natural environment. Such a conflict has caused the destruction to the land resources and fragmentation of the landscape accompanied by land desertification, the case is even serious in some localities.展开更多
Restoration of mining soils is important to the vegetation and environment.This study aimed to explore the variations in soil nutrient contents,microbial abundance,and biomass under different gradients of substrate am...Restoration of mining soils is important to the vegetation and environment.This study aimed to explore the variations in soil nutrient contents,microbial abundance,and biomass under different gradients of substrate amendments in mining soils to select effective measures.Soil samples were collected from the Bayan Obo mining region in Inner Mongolia Autonomous Region,China.Contents of soil organic matter(SOM),available nitrogen(AN),available phosphorus(AP),available potassium(AK),microbial biomass carbon/microbial biomass nitrogen(MBC/MBN)ratio,biomass,and bacteria,fungi,and actinomycetes abundance were assessed in Agropyron cristatum L.Gaertn.,Elymus dahuricus Turcz.,and Medicago sativa L.soils with artificial zeolite(AZ)and microbial fertilizer(MF)applied at T0(0 g/kg),T1(5 g/kg),T2(10 g/kg),and T3(20 g/kg).Redundancy analysis(RDA)and technique for order preference by similarity to ideal solution(TOPSIS)were used to identify the main factors controlling the variation of biomass.Results showed that chemical indices and microbial content of restored soils were far greater than those of control.The application of AZ significantly increases SOM,AN,and AP by 20.27%,23.61%,and 40.43%,respectively.AZ significantly increased bacteria,fungi,and actinomycetes abundance by 0.63,3.12,and 1.93 times of control,respectively.RDA indicated that AN,MBC/MBN ratio,and SOM were dominant predictors for biomass across samples with AZ application,explaining 87.6%of the biomass variance.SOM,MBC/MBN ratio,and AK were dominant predictors with MF application,explaining 82.9%of the biomass variance.TOPSIS indicated that T2 was the best dosage and the three plant species could all be used to repair mining soils.AZ and MF application at T2 concentration in the mining soils with M.sativa was found to be the most appropriate measure.展开更多
Planting trees was used as one of cost-effective measures for desertification control in add and semi-add areas of China. Woodland degradation, however, is becoming an inevitable issue in these areas. In this paper, a...Planting trees was used as one of cost-effective measures for desertification control in add and semi-add areas of China. Woodland degradation, however, is becoming an inevitable issue in these areas. In this paper, a typical county, Ejin Holo County, Inner Mongolia, China was selected for its assessment of artificial woodland degradation. A conceptual model for woodland degradation was delineated qualitatively based on field sampling survey, and four model-based indicators as humidity index （HI）, vegetation index （NDVI）, soil type （ST） and soil erosion modulus （EM） were screened out and used to a GIS-based method for artificial woodland degradation assessment in this semi-add agro-pastoral transitional area. All the indicator layers were overlaid and desertification assessed using simplified equation with equal weights for each indicators. The assessment results showed that in 336. 09 km^2 of total woodland area, 311.35 km^2 woodland were under degradation, and the area for slight, medium, severe degradation was 78.97, 119.73 and 112.65 km^2, respectively. It was suggested that much attention should be paid on woodland improvement and plant species selection, especially shrub species, before revegetation in similar areas.展开更多
Studying the climatic and environmental changes on different time scales in inland arid regions of Asia can greatly im‐prove our understanding of climatic influences for the Qinghai-Tibet Plateau in the context of gl...Studying the climatic and environmental changes on different time scales in inland arid regions of Asia can greatly im‐prove our understanding of climatic influences for the Qinghai-Tibet Plateau in the context of global change. Pollen, as a remnant of seed plants, is sensitive to environmental factors including precipitation, temperature and altitude, and is a clas‐sic proxy in environmental reconstruction. In the last two decades, great progress in the application of palynology to in‐land areas of Asia has highlighted the role of palynology in paleoclimatic and paleoenvironmental research. The main progress is as follows. (1) On the tectonic time scale of the late Cenozoic, the palaeoclimatological sequence has been es‐tablished on the basis of pollen percentage, concentration and taxon. Pollen data have revealed a continuous enhancement of drought in the inland arid region of Asia, in contrast to evidence acquired based on other proxies. (2) In the late Quater‐nary, an increase in herbaceous plants further supports the intensification of drought associated with global cooling. In more detail, the palynological record shows a glacial-interglacial pattern consistent with changes in global ice volume. (3) The Holocene pollen record has been established at a high resolution and across a wide range of inland areas. In general, it presents an arid grassland environment in the early Holocene, followed by the development of woody plants in the mid- to late-Holocene climate optimum. This pattern is related to moisture changes in areas dominated by the westerlies. There are also significant regional differences in the pattern and amplitude of vegetation response to the Holocene environment. (4) Modern pollen studies based on vegetation surveys, meteorological data and statistics show that topsoil palynology can better reflect regional vegetation types (e. g., grassland, meadow, desert). Drier climates yield higher pollen contents of drought-tolerant plants such as Chenopodioideae, Ephedra, and Nitriaria, while contents of Artemisia and Poaceae are greater under humid climates. Besides these achievements, problems remain in palynological research: for example, pol‐len extraction, identification, interpretation, and quantitative reconstruction. In the future, we encourage strengthened inter‐disciplinary cooperation to improve experimental methods and innovation. Firstly, we should strengthen palynological classification and improve the skill of identification;secondly, laboratory experiments are needed to better constrain pol‐len transport dynamics in water and air;thirdly, more rigorous mathematical principles will improve the reliability of re‐constructions and deepen the knowledge of plant geography;and finally, new areas and methods in palynology should be explored, for example DNA, UV-B and isotopic analysis. It is expected that palynology will continue to develop, and we hope it will continue to play an important role in the study of past climatic and environmental changes.展开更多
Because the large areas of Iran are on arid and semiarid belt of the world, it has many problems due to windstorms. Wind storms cause dust and haze due to a mass of fine sand or silt soil elevated in the atmosphere. I...Because the large areas of Iran are on arid and semiarid belt of the world, it has many problems due to windstorms. Wind storms cause dust and haze due to a mass of fine sand or silt soil elevated in the atmosphere. It makes heart disease-cardiovascular and respiratory and so is detrimental for the children. These have plagued the residents and so lives of them are disrupted every so often. In this research, the subject soil stabilization using adherence of poly vinyl acetate polymer as a way to reduce the production of dust is defined for prone area. In this paper, the effect of poly vinyl acetate polymer on silt soil has been studied. In this study the samples were uncompacted particles of soil with different amount of water-solvated polymer (0, 5, 10, 15, 20, 25, 30 grams per meter squared) poured over them. These samples are kept in experimental environment for 7 days. After ensuring complete dryness, their stabilities are tested against wind flow with 20 m/s speed. Results showed that adding more polymers to soil would considerably increase its particles’ stabilities. This stability is due to positive reaction of polymer with soil particles. The effect of this stability is maintained during sample drying time in the lab and the soil maintains its characteristics during testing. The best results are obtained for 20 grams polymer per meter squared, where caused an increase in stability to about 15 times that of the soil without polymer.展开更多
Understanding the dynamics of surface water area and their drivers is crucial for human survival and ecosystem stability in inland arid and semi-arid areas.This study took Gansu Province,China,a typical area with comp...Understanding the dynamics of surface water area and their drivers is crucial for human survival and ecosystem stability in inland arid and semi-arid areas.This study took Gansu Province,China,a typical area with complex terrain and variable climate,as the research subject.Based on Google Earth Engine,we used Landsat data and the Open-surface Water Detection Method with Enhanced Impurity Control method to monitor the spatiotemporal dynamics of surface water area in Gansu Province from 1985 to 2022,and quantitatively analyzed the main causes of regional differences in surface water area.The findings revealed that surface water area in Gansu Province expanded by 406.88 km2 from 1985 to 2022.Seasonal surface water area exhibited significant fluctuations,while permanent surface water area showed a steady increase.Notably,terrestrial water storage exhibited a trend of first decreasing and then increasing,correlated with the dynamics of surface water area.Climate change and human activities jointly affected surface hydrological processes,with the impact of climate change being slightly higher than that of human activities.Spatially,climate change affected the'source'of surface water to a greater extent,while human activities tended to affect the'destination'of surface water.Challenges of surface water resources faced by inland arid and semi-arid areas like Gansu Province are multifaceted.Therefore,we summarized the surface hydrology patterns typical in inland arid and semi-arid areas and tailored surface water'supply-demand'balance strategies.The study not only sheds light on the dynamics of surface water area in Gansu Province,but also offers valuable insights for ecological protection and surface water resource management in inland arid and semi-arid areas facing water scarcity.展开更多
Objective Any natural system is constantly exchanging material, energy and information with the environment, and all tkese processes follow the basic law of thermodynamics, with no exception of groundwater recharge a...Objective Any natural system is constantly exchanging material, energy and information with the environment, and all tkese processes follow the basic law of thermodynamics, with no exception of groundwater recharge and discharge process. On the basis of the principle of the first law of thermodynamics, the reverse geochemical simulation method is widely used in the study of groundwater recharge, runoff and drainage process. However, some studies only consider the material conservation in theprocess, but ignore the probability of the transformation.展开更多
hina is a large country with varied physical environments. Some of them are quite fragile and susceptible to land degradation, such as the arid and semiarid areas, as well as the slopeland of extensive mountain and hi...hina is a large country with varied physical environments. Some of them are quite fragile and susceptible to land degradation, such as the arid and semiarid areas, as well as the slopeland of extensive mountain and hilly areas. Therefore, human actions play a significant role in desertification processes. It was estimated that there are 3,327,000 km 2 of desertified areas in China, in which 1,533,000 km 2 are desert, gobi and sandy desertified areas. Most of them are in arid, semiarid and dry sub humid areas in northern China. Soil salinization is another kind of land desertification. It was estimated that about one fifth of the 66,700 km 2 of farmlands have been affected by soil salinization to certain extent. Grassland degradation is also serious in China. The main problems are the reduction of bio mass, decline of preferred species and soil erosion induced by overgrazing. In Inner Mongolia the area of degraded grasslands occupies 43.8 percent of the total available area of the grasslands. The productivity of grasslands in Tibet has decreased by 20 - 50 percent [21]. Soil and water erosion is more serious in China. Based on remote sensing general survey initiated by Ministry of Water Resources in 1992, the total soil eroded area is 3,670,000 km 2, occupying 38.2 percent of the total territorial area, in which 1,790,000 km 2 is water eroded area and 1,880,000 km 2 is wind eroded area.展开更多
基金supported the National Natural Science Foundation of China(42071371)the National Key R&D Program of China(2018YFB0505400).
文摘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.
文摘Climate change and increasing anthropogenic activities,such as over-exploitation of groundwater,are exerting unavoidable stress on groundwater resources.This study investigated the spatio-temporal variation of depth to groundwater level(DGWL)and the impacts of climatic(precipitation,maximum temperature,and minimum temperature)and anthropogenic(gross district product(GDP),population,and net irrigated area(NIA))variables on DGWL during 1994-2020.The study considered DGWL in 113 observation wells and piezometers located in arid western plains(Barmer and Jodhpur districts)and semi-arid eastern plains(Jaipur,Ajmer,Dausa,and Tonk districts)of Rajasthan State,India.Statistical methods were employed to examine the annual and seasonal patterns of DGWL,and the generalized additive model(GAM)was used to determine the impacts of climatic and anthropogenic variables on DGWL.During 1994-2020,except for Barmer District,where the mean annual DGWL was almost constant(around 26.50 m),all other districts exhibited increase in DGWL,with Ajmer District experiencing the most increase.The results also revealed that 36 observation wells and piezometers showed a statistically significant annual increasing trend in DGWL and 34 observation wells and piezometers exhibited a statistically significant decreasing trend in DGWL.Similarly,32 observation wells and piezometers showed an statistically significant increasing trend and 37 observation wells and piezometers showed a statistically significant decreasing trend in winter;33 observation wells and piezometers indicated a statistically significant increasing trend and 34 had a statistically significant decreasing trend in post-monsoon;35 observation wells and piezometers exhibited a statistically significant increasing trend and 32 observation wells and piezometers showed a statistically significant decreasing trend in pre-monsoon;and 36 observation wells and piezometers reflected a statistically significant increasing trend and 30 observation wells and piezometers reflected a statistically significant decreasing trend in monsoon.Interestingly,most of the observation wells and piezometers with increasing trends of DGWL were located in Dausa and Jaipur districts.Furthermore,the GAM analysis revealed that climatic variables,such as precipitation,significantly affected DGWL in Barmer District,and DGWL in all other districts was influenced by anthropogenic variables,including GDP,NIA,and population.As a result,stringent regulations should be implemented to curb excessive groundwater extraction,manage agricultural water demand,initiate proactive aquifer recharge programs,and strengthen sustainable management in these water-scarce regions.
文摘The economy of most rural locations in the semi-arid region of Llano Estacado in the southern United States is predominantly based on agriculture, primarily beef and wheat (Triticum aestivum L.) production. This region is prone to drought and is projected to experience a drier climate. Droughts that coincide with the critical phenological phases of a crop can be remarkably costly. Although drought cannot be prevented, its losses can be minimized through mitigation measures if it is predicted in advance. Predicting yield loss from an imminent drought is an important need of stakeholders. One way to fulfill this need is using an agricultural drought index, such as the Agricultural Reference Index for Drought (ARID). Being plant physiology-based, ARID can represent drought-yield relationships accurately. This study developed an ARID-based yield model for predicting the drought-induced yield loss for winter wheat in this region by accounting for its phenological phase-specific sensitivity to water stress. The reasonable values of the drought sensitivity coefficients of the yield model indicated that it could reflect the phenomenon of water stress decreasing the winter wheat yields in this region reasonably. The values of the various metrics used to evaluate the model, including Willmott Index (0.86), Nash-Sutcliffe Index (0.61), and percentage error (26), indicated that the yield model performed fairly well at predicting the drought-induced yield loss for winter wheat. The yield model may be useful for predicting the drought-induced yield loss for winter wheat in the study region and scheduling irrigation allocation based on phenological phase-specific drought sensitivity.
文摘Rainwater harvesting (RWH) systems have been developed to compensate for shortage in the water supply worldwide. Such systems are not very common in arid areas, particularly in the Gulf Region, due to the scarcity of rainfall and their reduced efficiency in covering water demand and reducing water consumption rates. In spite of this, RWH systems have the potential to reduce urban flood risks, particularly in densely populated areas. This study aimed to assess the potential use of RWH systems as urban flood mitigation measures in arid areas. Their utility in the retention of stormwater runoff and the reduction of water depth and extent were evaluated. The study was conducted in a residential area in Bahrain that experienced waterlogging after heavy rainfall events. The water demand patterns of housing units were analyzed, and the daily water balance for RWH tanks was evaluated. The effect of the implementation of RWH systems on the flood volume was evaluated with a two-dimensional hydrodynamic model. Flood simulations were conducted in several rainfall scenarios with different probabilities of occurrence. The results showed significant reductions in the flood depth and flood extent, but these effects were highly dependent on the rainfall intensity of the event. RWH systems are effective flood mitigation measures, particularly in urban arid regions short of proper stormwater control infrastructure, and they enhance the resilience of the built environment to urban floods.
基金supported jointlyby the Chinese Academy of Sciences under Grant KZCX2-YW-220the National Basic Research Program of Chinaunder Grant 2009CB421405the National Natural Sci-ence Foundation of China under Grant No.40730952
文摘To improve the land surface simulation in the arid and semi-arid areas of northern China, the observational data from two field experiments in Dunhuang and Tongyu are used to optimize the parameters in the land surface model, BATS, through calibration with the multicriteria method. Sensitivity analysis to the parameters in Dunhuang and Tongyu indicates that different parameters need to be calibrated in two sites with different environmental and climate regimes. Comparison of observed sensible heat flux, latent heat flux, and ground surface temperature with the simulated ones shows the simulations with the optimized parameters have been substantially improved. Especially, the holistic simulations with the calibration of the parameter values are much closer to the observations in the arid region （Dunhuang）, and the energy partition with the calibrated parameters can also be simulated well in the semi-arid region （Tongyu）. Whole results demonstrate that the parameter calibration of the land surface model is important when the model is to be used to investigate the land-air interaction.
文摘Dealing with the regional land surfaces heat fluxes over inhomogeneous land surfaces in arid and semi-arid areas is an important but not an easy issue. In this study, one parameterization method based on satellite remote sensing and field observations is proposed and tested for deriving the regional land surface heat fluxes over inhomogeneous landscapes. As a case study, the method is applied to the Dunhuang experimental area and the HEIFE (Heihe River Field Experiment, 1988-1994) area. The Dunhuang area is selected as a basic experimental area for the Chinese National Key Programme for Developing Basic Sciences: Research on the Formation Mechanism and Prediction Theory of Severe Climate Disaster in China (G1998040900, 1999-2003). The four scenes of Landsat TM data used in this study are 3 June 2000, 22 August 2000, and 29 January 2001 for the Dunhuang area and 9 July 1991 for the HEIFE area. The regional distributions of land surface variables, vegetation variables, and heat fluxes over inhomogeneous landscapes in arid and semi-arid areas are obtained in this study.
基金supported by the National Basic Research Program of China (Grant No. 2006CB403702)the National High Technology Research and Development Program of China (Grant No. 2006AA06A301)
文摘Climatic characteristics of broadband solarradiation (Rs) in Chinese arid and semi-arid areas are reported in this study. The annual average daily Rs in thearid and semi-arid areas is 16.3 ± 5.77 and 15.3 ± 5.16 MJm-2 d-1, respectively. The highest value (17.2 ± 5.84 MJm-2 d-1) appears in an arid area at Linze. The lowest valueappears in the semi-arid area of Ansai. Pronounced seasonal variation of Rs is observed with the highest value insummer and the lowest in winter. The clearness indexshowed similar seasonal pattern at most sites, with theminimum observed in the summer and the highest valuesin winter at both arid and semi-arid areas. The seasonalvariation of the ratio of Rs to its extraterrestrial value Kt inthe arid area is more significant than that observed in thesemi-arid region, and it is caused by the different range ofvariation of water vapor between arid and semi-arid areasThe seasonal fluctuations in Rs and Kt are mainly controlled by the water vapor content in these areas. Theaerosol particles have significant influence on Rs and Kt atstations with higher aerosol burden.
文摘1. The crux of the environment administration problem is theeconomic development As we Know that the evolution of environment is not only due to Nature itself, but al-so to human being particularly. In the course of history, the Loess Plateau in China, oncewoody and rich in plants has now become a serious soil-erosion area on which lies thou-
文摘Participatory irrigation management （PIM） is theoretically assumed to reduce poverty significantly, but its practical experience and challenges are yet researched and documented in Tanzania. The study aimed at assessing challenges observed during implementation of PIM approach for food security in semi-arid areas of Tanzania. Data were collected through questionnaire, participatory rapid appraisal （PRA） tools, key informants interview, Focus Group Discussion （FGD）, observation and literature review. Data collected from questionnaire were analyzed using SPSS. Data fi＇om other methods were analyzed using content analysis. The study revealed that PIM approach has contribution in improving food security at household level due to involvement of communities in water management activities and decision making, which enhanced availability of irrigation water and increased crop production. However, there were challenges observed during implementation of the approach, including the minimum participation of beneficiaries in decision making during planning and designing stages, which means that inadequate devolution of power among scheme owners, inadequate and lack of transparency on income expenditure in water utilization associations （WUAs）, water conflict among WUAs members, conflict between farmers and livestock keepers and conflict between WUAs and village government leaders regarding training opportunities and status. The rules and regulation of WUAs were not legally recognized by the national courts and few farmers who planted trees around water sources. However, it was realized that some of the mentioned challenges were rectified by farmers themselves and facilitated by government officials. The study recommends that the identified challenges need to be rectified for farmers to realize more on the importance of PIM approach as it was realized in other Asian countries.
基金the National Basic Research Program of China (973 Program, 2006CB500401)
文摘Based on 3 years （2003-05） of the eddy covariance （EC） observations on degraded grassland and cropland surfaces in a semi-arid area of Tongyu （44°25′N, 122°52′E, 184 m a.s.1.）, Northeast China, seasonal and annual variations of water, energy and CO2 fluxes have been investigated. The soil moisture in the thin soil layer （at 0.05, 0.10 and 0.20 m） clearly indicates the pronounced annual wet-dry cycle; the annual cycle is divided into the wet （growing season） and dry seasons （non-growing season）. During the growing season （from May to September）, the sensible and latent heat fluxes showed a linear dependence on the global solar radiation. However, in the non-growing season, the latent heat flux was always less than 50 W m^-2, while the available energy was dissipated as sensible, rather than latent heat flux. During the growing season in 2003-05, the daily average sensible and latent heat fluxes were larger on the cropland surface than on the degraded grassland surface. The cropland ecosystem absorbed more CO2 than the degraded grassland ecosystem in the growing season in 2003-05. The total evapotranspiration on the cropland was more than the total precipitation, while the total evapotranspiration on the degraded grassland was almost the same as the total annual precipitation in the growing season. The soil moisture had a good correlation with the rainfall in the growing season. Precipitation in the growing season is an important factor on the water and carbon budget in the semi-arid area.
基金supported by the Special Foundation of National Science & Technology Supporting Plan (2011BAD29B09)the National Natural Science Foundation of China (31172039)+2 种基金the ‘111’ Project from the Ministry of Edu- cation and the State Administration of Foreign Experts Affairs (B12007)the Supporting Project of Young Technology Nova of Shaanxi Province (2010KJXX-04)the Supporting Plan of Young Elites and basic operational cost of research from Northwest A&F University
文摘The division of arid areas is important in water and land resources management, planning and for a long-term agricultural, economic and social planning. Northwest China （NW） dominates the main arid areas in China. There is thus a need to adopt adequate concepts relative to the scope of arid areas of NW China and identify its climate types and characteristics. In this study, we analyzed climatic data over the last 30 years （1981-2010） from 191 stations in three provinces and three autonomous regions of NW China. The factor-cluster analysis technique （FC）, an objective and automated method was employed to classify the dry/wet climate zones. The traditional methods with predefined thresholds were adopted for providing a comparison with FC. The results showed that the wet/dry climate zones by FC were mainly distributed along mountains, rivers and desert borders. Climate-division boundaries relied heavily on the major terrain features surrounding the grouped stations. It also showed that the climate was dry in the plain sandy areas but relatively wet in the high mountain areas. FC method can reflect the climate characteristics more fully in NW China with varied and complicated topography, and outperform the tradi- tional climate classifications. Arid areas of NW China were defined as four climate types, including five resultant classes in FC classifications. The Qinling and Da Hinggan Mountains were two important boundaries, besides main administrative boundaries. The results also indicated that there are some differences between two traditional clas- sifications. The precipitation moved and fluctuated to an extent, which confirmed that climate change played an important role in the dry/wet climate zoning, and the boundaries of dry/wet climate zones might change and migrate with time. This paper is expected to provide a more in-depth understanding on the climate characteristics in arid areas of NW China, and then contribute to formulate reasonable water and land management planning and agri- cultural production programs.
基金The National Basic Research Program of China, No.2006CB400505 National Natural Science Foundation of China, No.40171007 Key Project of Ministry of Land and Resources, No.20010102
文摘Rapid land landscape change has taken place in many arid and semi-arid regions such as the vulnerable ecological area over the last decade. In this paper, we quantified land landscape change of Yulin in this area between 1985 and 2000 using remote sensing and GIS. It was found that fallow landscape decreased by 125,148 hm^2 while grassland and woodland increased by 107,975 hm^2 and 17,157 hm^2, respectively. The major factors responsible for these changes are identified as the change in the government policy on preserving the environment, continued growth in mining, and urbanization. The efforts in restoring the deteriorated ecosystem have reaped certain benefits in reducing the spatial extent of sandy land through replacement by non-irrigated farmland, woodland and grassland. On the other hand, continued expansion of mining industry and urbanization has exerted adverse impacts on the land landscape. At present regional economic development conflicts directly with the protection of the natural environment. Such a conflict has caused the destruction to the land resources and fragmentation of the landscape accompanied by land desertification, the case is even serious in some localities.
基金supported by the Beijing Forestry University(BJFU),China。
文摘Restoration of mining soils is important to the vegetation and environment.This study aimed to explore the variations in soil nutrient contents,microbial abundance,and biomass under different gradients of substrate amendments in mining soils to select effective measures.Soil samples were collected from the Bayan Obo mining region in Inner Mongolia Autonomous Region,China.Contents of soil organic matter(SOM),available nitrogen(AN),available phosphorus(AP),available potassium(AK),microbial biomass carbon/microbial biomass nitrogen(MBC/MBN)ratio,biomass,and bacteria,fungi,and actinomycetes abundance were assessed in Agropyron cristatum L.Gaertn.,Elymus dahuricus Turcz.,and Medicago sativa L.soils with artificial zeolite(AZ)and microbial fertilizer(MF)applied at T0(0 g/kg),T1(5 g/kg),T2(10 g/kg),and T3(20 g/kg).Redundancy analysis(RDA)and technique for order preference by similarity to ideal solution(TOPSIS)were used to identify the main factors controlling the variation of biomass.Results showed that chemical indices and microbial content of restored soils were far greater than those of control.The application of AZ significantly increases SOM,AN,and AP by 20.27%,23.61%,and 40.43%,respectively.AZ significantly increased bacteria,fungi,and actinomycetes abundance by 0.63,3.12,and 1.93 times of control,respectively.RDA indicated that AN,MBC/MBN ratio,and SOM were dominant predictors for biomass across samples with AZ application,explaining 87.6%of the biomass variance.SOM,MBC/MBN ratio,and AK were dominant predictors with MF application,explaining 82.9%of the biomass variance.TOPSIS indicated that T2 was the best dosage and the three plant species could all be used to repair mining soils.AZ and MF application at T2 concentration in the mining soils with M.sativa was found to be the most appropriate measure.
基金This paper is funded by National Natural Science Fund (30171205) and National Tenth-year-plan Key Sci&tech Project (2005BA517A04)
文摘Planting trees was used as one of cost-effective measures for desertification control in add and semi-add areas of China. Woodland degradation, however, is becoming an inevitable issue in these areas. In this paper, a typical county, Ejin Holo County, Inner Mongolia, China was selected for its assessment of artificial woodland degradation. A conceptual model for woodland degradation was delineated qualitatively based on field sampling survey, and four model-based indicators as humidity index （HI）, vegetation index （NDVI）, soil type （ST） and soil erosion modulus （EM） were screened out and used to a GIS-based method for artificial woodland degradation assessment in this semi-add agro-pastoral transitional area. All the indicator layers were overlaid and desertification assessed using simplified equation with equal weights for each indicators. The assessment results showed that in 336. 09 km^2 of total woodland area, 311.35 km^2 woodland were under degradation, and the area for slight, medium, severe degradation was 78.97, 119.73 and 112.65 km^2, respectively. It was suggested that much attention should be paid on woodland improvement and plant species selection, especially shrub species, before revegetation in similar areas.
基金the NSFC(41772181,41807440 and 41888101)the Strategic Priority Research Program of CAS(No.XDA20070200)+4 种基金Young Top Talents Project of the"Ten Thousand Youth Program"of the Organization Department of the Central Committee of the CPCYouth Innovation Promotion Association,CAS(2014383)"Light of West China"Program,CASand the NSF of Gansu Province(18JR3RA395)We thank Miao's group members and anonymous referees for discussions and their constructive suggestions。
文摘Studying the climatic and environmental changes on different time scales in inland arid regions of Asia can greatly im‐prove our understanding of climatic influences for the Qinghai-Tibet Plateau in the context of global change. Pollen, as a remnant of seed plants, is sensitive to environmental factors including precipitation, temperature and altitude, and is a clas‐sic proxy in environmental reconstruction. In the last two decades, great progress in the application of palynology to in‐land areas of Asia has highlighted the role of palynology in paleoclimatic and paleoenvironmental research. The main progress is as follows. (1) On the tectonic time scale of the late Cenozoic, the palaeoclimatological sequence has been es‐tablished on the basis of pollen percentage, concentration and taxon. Pollen data have revealed a continuous enhancement of drought in the inland arid region of Asia, in contrast to evidence acquired based on other proxies. (2) In the late Quater‐nary, an increase in herbaceous plants further supports the intensification of drought associated with global cooling. In more detail, the palynological record shows a glacial-interglacial pattern consistent with changes in global ice volume. (3) The Holocene pollen record has been established at a high resolution and across a wide range of inland areas. In general, it presents an arid grassland environment in the early Holocene, followed by the development of woody plants in the mid- to late-Holocene climate optimum. This pattern is related to moisture changes in areas dominated by the westerlies. There are also significant regional differences in the pattern and amplitude of vegetation response to the Holocene environment. (4) Modern pollen studies based on vegetation surveys, meteorological data and statistics show that topsoil palynology can better reflect regional vegetation types (e. g., grassland, meadow, desert). Drier climates yield higher pollen contents of drought-tolerant plants such as Chenopodioideae, Ephedra, and Nitriaria, while contents of Artemisia and Poaceae are greater under humid climates. Besides these achievements, problems remain in palynological research: for example, pol‐len extraction, identification, interpretation, and quantitative reconstruction. In the future, we encourage strengthened inter‐disciplinary cooperation to improve experimental methods and innovation. Firstly, we should strengthen palynological classification and improve the skill of identification;secondly, laboratory experiments are needed to better constrain pol‐len transport dynamics in water and air;thirdly, more rigorous mathematical principles will improve the reliability of re‐constructions and deepen the knowledge of plant geography;and finally, new areas and methods in palynology should be explored, for example DNA, UV-B and isotopic analysis. It is expected that palynology will continue to develop, and we hope it will continue to play an important role in the study of past climatic and environmental changes.
文摘Because the large areas of Iran are on arid and semiarid belt of the world, it has many problems due to windstorms. Wind storms cause dust and haze due to a mass of fine sand or silt soil elevated in the atmosphere. It makes heart disease-cardiovascular and respiratory and so is detrimental for the children. These have plagued the residents and so lives of them are disrupted every so often. In this research, the subject soil stabilization using adherence of poly vinyl acetate polymer as a way to reduce the production of dust is defined for prone area. In this paper, the effect of poly vinyl acetate polymer on silt soil has been studied. In this study the samples were uncompacted particles of soil with different amount of water-solvated polymer (0, 5, 10, 15, 20, 25, 30 grams per meter squared) poured over them. These samples are kept in experimental environment for 7 days. After ensuring complete dryness, their stabilities are tested against wind flow with 20 m/s speed. Results showed that adding more polymers to soil would considerably increase its particles’ stabilities. This stability is due to positive reaction of polymer with soil particles. The effect of this stability is maintained during sample drying time in the lab and the soil maintains its characteristics during testing. The best results are obtained for 20 grams polymer per meter squared, where caused an increase in stability to about 15 times that of the soil without polymer.
基金This research was supported by the Third Xinjiang Scientific Expedition Program(2021xjkk010102)the National Natural Science Foundation of China(41261047,41761043)+1 种基金the Science and Technology Plan of Gansu Province,China(20YF3FA042)the Youth Teacher Scientific Capability Promoting Project of Northwest Normal University,Gansu Province,China(NWNU-LKQN-17-7).
文摘Understanding the dynamics of surface water area and their drivers is crucial for human survival and ecosystem stability in inland arid and semi-arid areas.This study took Gansu Province,China,a typical area with complex terrain and variable climate,as the research subject.Based on Google Earth Engine,we used Landsat data and the Open-surface Water Detection Method with Enhanced Impurity Control method to monitor the spatiotemporal dynamics of surface water area in Gansu Province from 1985 to 2022,and quantitatively analyzed the main causes of regional differences in surface water area.The findings revealed that surface water area in Gansu Province expanded by 406.88 km2 from 1985 to 2022.Seasonal surface water area exhibited significant fluctuations,while permanent surface water area showed a steady increase.Notably,terrestrial water storage exhibited a trend of first decreasing and then increasing,correlated with the dynamics of surface water area.Climate change and human activities jointly affected surface hydrological processes,with the impact of climate change being slightly higher than that of human activities.Spatially,climate change affected the'source'of surface water to a greater extent,while human activities tended to affect the'destination'of surface water.Challenges of surface water resources faced by inland arid and semi-arid areas like Gansu Province are multifaceted.Therefore,we summarized the surface hydrology patterns typical in inland arid and semi-arid areas and tailored surface water'supply-demand'balance strategies.The study not only sheds light on the dynamics of surface water area in Gansu Province,but also offers valuable insights for ecological protection and surface water resource management in inland arid and semi-arid areas facing water scarcity.
基金granted by the National Natural Science Fund of China(Grant no.51578212)
文摘Objective Any natural system is constantly exchanging material, energy and information with the environment, and all tkese processes follow the basic law of thermodynamics, with no exception of groundwater recharge and discharge process. On the basis of the principle of the first law of thermodynamics, the reverse geochemical simulation method is widely used in the study of groundwater recharge, runoff and drainage process. However, some studies only consider the material conservation in theprocess, but ignore the probability of the transformation.
文摘hina is a large country with varied physical environments. Some of them are quite fragile and susceptible to land degradation, such as the arid and semiarid areas, as well as the slopeland of extensive mountain and hilly areas. Therefore, human actions play a significant role in desertification processes. It was estimated that there are 3,327,000 km 2 of desertified areas in China, in which 1,533,000 km 2 are desert, gobi and sandy desertified areas. Most of them are in arid, semiarid and dry sub humid areas in northern China. Soil salinization is another kind of land desertification. It was estimated that about one fifth of the 66,700 km 2 of farmlands have been affected by soil salinization to certain extent. Grassland degradation is also serious in China. The main problems are the reduction of bio mass, decline of preferred species and soil erosion induced by overgrazing. In Inner Mongolia the area of degraded grasslands occupies 43.8 percent of the total available area of the grasslands. The productivity of grasslands in Tibet has decreased by 20 - 50 percent [21]. Soil and water erosion is more serious in China. Based on remote sensing general survey initiated by Ministry of Water Resources in 1992, the total soil eroded area is 3,670,000 km 2, occupying 38.2 percent of the total territorial area, in which 1,790,000 km 2 is water eroded area and 1,880,000 km 2 is wind eroded area.
