Background,aim,and scope Stable isotope in water could respond sensitively to the variation of environment and be reserved in different geological archives,although they are scarce in the environment.And the methods d...Background,aim,and scope Stable isotope in water could respond sensitively to the variation of environment and be reserved in different geological archives,although they are scarce in the environment.And the methods derived from the stable isotope composition of water have been widely applied in researches on hydrometeorology,weather diagnosis,and paleoclimate reconstruction,which help well for understanding the water-cycle processes in one region.Here,it is aimed to explore the temporal changes of stable isotopes in precipitation from Adelaide,Australia and determine the influencing factors at different timescales.Materials and methods Based on the isotopic data of daily precipitation over four years collected in Adelaide,Australia,the variation characteristics of dailyδD,δ^(18)O,and dexcess in precipitation and its relationship with meteorological elements were analyzed.Results The results demonstrated the local meteoric water line(LMWL)in Adelaide,wasδD=6.38×δ^(18)O+6.68,with a gradient less than 8.There is a significant negative correlation between dailyδ^(18)O and precipitation amount or relative humidity at daily timescales in both the whole year and wither/summerhalf year(p<0.001),but a significant positive correlation between dailyδ^(18)O and temperature in the whole year and the winter half-year(p<0.001).Discussion The correlation coefficients betweenδ^(18)O and daily mean temperature didn’t show a significant positive correlation,which may be attributed to that the precipitation in Adelaide area in January was mainly influenced by strong convective weather,and the stable isotope values in precipitation were significantly negative.Furthermore,this propose was also evidenced by the results from dexcess of precipitation with larger value in the winter half-year than that in the summer half-year,which may be resulted from the precipitation events in winter are mostly influenced by oceanic water vapor,while the sources of water vapor in summer precipitation events are more complicated and influenced by strong convective weather.On the other hand,the slope and intercept of theδ^(18)O—P regression lines in the summer months(-0.41 and 0.50‰)are larger and smaller than those in the winter months(-0.22 and-2.15‰),respectively,indicating that the precipitation stable isotopes have a relatively stronger rainout effect in the summer months than in the winter months.Besides,the measured values ofδ^(18)O in daily precipitation have a good linear relationship with our simulated values ofδ^(18)O,demonstrating the established regression model could provide a reliable simulation for theδ^(18)O values in daily precipitation in Adelaide area.It’s worth noting that the precipitation events with low precipitation amount,low relative humidity and high temperature,usually had relatively small slope and intercept of MWL,implying that raindrops may be strongly affected by sub-cloud secondary evaporation in the falling process.Conclusions The variation ofδ^(18)O in daily precipitation from Adelaide region was controlled by different factors at different timescales.And the water vapor sources and the meteorological conditions of precipitation events(such as the degree of sub-cloud secondary evaporation)also played an important role on the variation ofδ^(18)O.Recommendations and perspectives Stable isotope in daily precipitation can provide more accurate information about water-cycle and atmosphere circulation,it is therefore necessary to continue to collect and analyze daily-scale precipitation data over a longer time span.The results of this study will provide the basis for the fields of hydrometeorology,meteorological diagnosis and paleoclimate reconstruction in Adelaide,Australia.展开更多
Global climate change and increased human consumption have aggravated the uneven spatiotemporal distribution of watershed water resources, affecting the water provision supply and demand state. However, this problem h...Global climate change and increased human consumption have aggravated the uneven spatiotemporal distribution of watershed water resources, affecting the water provision supply and demand state. However, this problem has often been ignored. The present study used the Xiangjiang River basin(XRB) as the study area, and the Integrated Valuation of Ecosystem Services and Trade-offs(InVEST) model, demand quantification model,supply–demand ratio, and water flow formula were applied to explore the spatial heterogeneity, flow, and equilibrium between water supply and demand. The results demonstrated significant spatial heterogeneity in the upstream, midstream, and downstream regions.The areas of water shortage were mainly located the downstream of the Changsha–Zhuzhou–Xiangtan urban agglomeration, and the Hengyang basin was the most scarcity area. Affected by terrain gradients and human needs, water flow varied from-16.33 × 10^(8) m^(3) to 13.69 × 10^(8) m^(3)from the upstream to the downstream area, which provided a possibility to reduce spatial heterogeneity. In the future, measures such as strengthening water resource system control,sponge city construction, and dynamic monitoring technology should be taken to balance the supply and demand of water in different river sections of the basin. This study can provide references for regulating water resources allocation in different reaches of the basin.展开更多
With the continuous development of remote sensing(RS)technology,the surface information can be collected conveniently and quickly by using the popular unmanned aerial vehicle(UAV).The application of UAV low altitude R...With the continuous development of remote sensing(RS)technology,the surface information can be collected conveniently and quickly by using the popular unmanned aerial vehicle(UAV).The application of UAV low altitude RS technology in road safety in intelligent area has certain practical significance.It can provide safety warning for most drivers,and provide auxiliary decision-making for the road supervision department.Through the collection,processing,calculation and analysis of the road image,the UAV can find out the road obstacles with potential safety hazards,identify the road pit,calculate the radius and depth of the road pit through the digital mapping system,predict the accident risk according to different speed and provide scientific basis for the road safety monitoring.At the same time,UAV can provide repair scheme for damaged roads,estimate the quantity of materials needed for repair,and achieve the target of resource saving and efficiency improvement.The experimental results show that the UAV can not only provide scientific prediction information for driving safety,but also provide relatively accurate material consumption for road repair.展开更多
Optimizing rural settlements is an important measure to cope with rural decline, and improve the quality of rural life and attractions. This study introduces the "life quality theory". Based on the mechanism...Optimizing rural settlements is an important measure to cope with rural decline, and improve the quality of rural life and attractions. This study introduces the "life quality theory". Based on the mechanisms governing the interactions between rural settlement space and life quality, this study examines how to optimize the spatial organization of rural settlements. Three aspects are evaluated – the integration of rural settlement spatial functions, optimization of spatial structure, and regulation of spatial scale – with the objective of building an optimization mode and framework for the spatial organization of rural settlements with high life quality. Our results suggest the following:(1) The settlement is the spatial carrier of life quality, which is an essential settlement component, and these two aspects influence and improve each other. Therefore, reasonable rural settlement space is an important precondition for higher life quality.(2) The spatial function types of rural settlements can be divided into those that maintain livelihoods, develop industry, and upgrade life quality. Optimizing spatial organization of rural settlements based on life quality requires promoting the maintenance of livelihood, integration of industrial development, and implantation in quality improvement.(3) There are two important components of optimizing the spatial organization of rural settlements. One is promoting the organic concentration of living, agricultural, and industrial spaces, the reasonable distribution of social intercourse, recreational, and services spaces, and the organic balance of living, production, and ecological spaces, so as to reasonably optimize the combination of internal spatial types in settlements. The other is forming a functional structure level of a "comprehensive village–featured village" and building spatial organization settlement modes connected by rural roads by relocating and adjusting the function of villages. These changes would require the destruction of underdeveloped villages, retaining normal villages, enlarging important villages, and constructing new villages.(4) As an ideal mode for optimizing rural settlements space based on life quality, the Rural Road-Oriented Development Model(RROD model) should be built at a rational scale for unit settlement and distance between settlements, leading to a fully functional RROD system with rational structure, auxiliary facility, and well-organized distribution.展开更多
Rural gentrification is deeply characterized by institutional context and spatiotemporal heterogeneity.Based on a diachronic field investigation,this paper constructs an analytical framework for gentrifying rural comm...Rural gentrification is deeply characterized by institutional context and spatiotemporal heterogeneity.Based on a diachronic field investigation,this paper constructs an analytical framework for gentrifying rural community development(GRCD)with a“community”theoretical perspective and analytical approach,defines the concept of GRCD,and analyzes the main characteristics,formation mechanism and regulation path of a typical gentrifying rural community in the Panyang River Basin of Bama County,Guangxi.Driven by factors such as the complex flow and heterogeneous living space practices of the host-guest community,the longevity“myth”led by commercial capital and consumption demand,and multiple action logics and desertification community governance,great changes have occurred in the social space and material landscape of the rural longevity community.Such changes include comprehensive reconstruction of the resident population,surface interaction and social separation of the host-guest community,residential structure change and settlement landscape renewal,and delocalization of the healing landscape and lifestyle changes.We propose policy insights in three areas:public and localization institutional arrangements,shared and comfortable gentrifying rural community making,and inclusive and synergistic gentrifying rural community governance.Through these aspects,we provide insights from the Chinese case for the gentrification and community development of rural areas in the Global South.展开更多
Since 2007,the Chinese government has initiated the building of national eco-cultural protection areas(NECPAs),thereby embarking on a significant transformation of the model of intangible cultural heritage(IC H)protec...Since 2007,the Chinese government has initiated the building of national eco-cultural protection areas(NECPAs),thereby embarking on a significant transformation of the model of intangible cultural heritage(IC H)protection in China.To understand the origin and outputs of this policy,this paper demonstrates the context of China's NECPAs.It proposes a conceptual NECPA framework that mainly features regional overall ICH protection.This is followed by an examination of the case of Xiangxi in Western Hunan as a pilot zone for China’s eco-cultural protection.Xiangxi has performed much related work to promote NECPAs and made great progress in regional overall ICH protection.This insight suggests that there are benefits and costs associated with promotion of China's NECPAs and regional overall ICH protection.Despite the advantages of institutional innovation,the unexpected side effects actually undermine the success of plan implementation.展开更多
文摘Background,aim,and scope Stable isotope in water could respond sensitively to the variation of environment and be reserved in different geological archives,although they are scarce in the environment.And the methods derived from the stable isotope composition of water have been widely applied in researches on hydrometeorology,weather diagnosis,and paleoclimate reconstruction,which help well for understanding the water-cycle processes in one region.Here,it is aimed to explore the temporal changes of stable isotopes in precipitation from Adelaide,Australia and determine the influencing factors at different timescales.Materials and methods Based on the isotopic data of daily precipitation over four years collected in Adelaide,Australia,the variation characteristics of dailyδD,δ^(18)O,and dexcess in precipitation and its relationship with meteorological elements were analyzed.Results The results demonstrated the local meteoric water line(LMWL)in Adelaide,wasδD=6.38×δ^(18)O+6.68,with a gradient less than 8.There is a significant negative correlation between dailyδ^(18)O and precipitation amount or relative humidity at daily timescales in both the whole year and wither/summerhalf year(p<0.001),but a significant positive correlation between dailyδ^(18)O and temperature in the whole year and the winter half-year(p<0.001).Discussion The correlation coefficients betweenδ^(18)O and daily mean temperature didn’t show a significant positive correlation,which may be attributed to that the precipitation in Adelaide area in January was mainly influenced by strong convective weather,and the stable isotope values in precipitation were significantly negative.Furthermore,this propose was also evidenced by the results from dexcess of precipitation with larger value in the winter half-year than that in the summer half-year,which may be resulted from the precipitation events in winter are mostly influenced by oceanic water vapor,while the sources of water vapor in summer precipitation events are more complicated and influenced by strong convective weather.On the other hand,the slope and intercept of theδ^(18)O—P regression lines in the summer months(-0.41 and 0.50‰)are larger and smaller than those in the winter months(-0.22 and-2.15‰),respectively,indicating that the precipitation stable isotopes have a relatively stronger rainout effect in the summer months than in the winter months.Besides,the measured values ofδ^(18)O in daily precipitation have a good linear relationship with our simulated values ofδ^(18)O,demonstrating the established regression model could provide a reliable simulation for theδ^(18)O values in daily precipitation in Adelaide area.It’s worth noting that the precipitation events with low precipitation amount,low relative humidity and high temperature,usually had relatively small slope and intercept of MWL,implying that raindrops may be strongly affected by sub-cloud secondary evaporation in the falling process.Conclusions The variation ofδ^(18)O in daily precipitation from Adelaide region was controlled by different factors at different timescales.And the water vapor sources and the meteorological conditions of precipitation events(such as the degree of sub-cloud secondary evaporation)also played an important role on the variation ofδ^(18)O.Recommendations and perspectives Stable isotope in daily precipitation can provide more accurate information about water-cycle and atmosphere circulation,it is therefore necessary to continue to collect and analyze daily-scale precipitation data over a longer time span.The results of this study will provide the basis for the fields of hydrometeorology,meteorological diagnosis and paleoclimate reconstruction in Adelaide,Australia.
基金supported by National Natural Science Foundation of China(grant number 42171258,41877084)Natural Science Foundation of Hunan Province(grant number 2021JJ30448)。
文摘Global climate change and increased human consumption have aggravated the uneven spatiotemporal distribution of watershed water resources, affecting the water provision supply and demand state. However, this problem has often been ignored. The present study used the Xiangjiang River basin(XRB) as the study area, and the Integrated Valuation of Ecosystem Services and Trade-offs(InVEST) model, demand quantification model,supply–demand ratio, and water flow formula were applied to explore the spatial heterogeneity, flow, and equilibrium between water supply and demand. The results demonstrated significant spatial heterogeneity in the upstream, midstream, and downstream regions.The areas of water shortage were mainly located the downstream of the Changsha–Zhuzhou–Xiangtan urban agglomeration, and the Hengyang basin was the most scarcity area. Affected by terrain gradients and human needs, water flow varied from-16.33 × 10^(8) m^(3) to 13.69 × 10^(8) m^(3)from the upstream to the downstream area, which provided a possibility to reduce spatial heterogeneity. In the future, measures such as strengthening water resource system control,sponge city construction, and dynamic monitoring technology should be taken to balance the supply and demand of water in different river sections of the basin. This study can provide references for regulating water resources allocation in different reaches of the basin.
基金National Natural Science Foundation(51708098)Key Laboratory Project of National Bureau of Surveying and Mapping Geographic Information for Watershed Ecology and Geographic Environment Monitoring(WE2016018)。
文摘With the continuous development of remote sensing(RS)technology,the surface information can be collected conveniently and quickly by using the popular unmanned aerial vehicle(UAV).The application of UAV low altitude RS technology in road safety in intelligent area has certain practical significance.It can provide safety warning for most drivers,and provide auxiliary decision-making for the road supervision department.Through the collection,processing,calculation and analysis of the road image,the UAV can find out the road obstacles with potential safety hazards,identify the road pit,calculate the radius and depth of the road pit through the digital mapping system,predict the accident risk according to different speed and provide scientific basis for the road safety monitoring.At the same time,UAV can provide repair scheme for damaged roads,estimate the quantity of materials needed for repair,and achieve the target of resource saving and efficiency improvement.The experimental results show that the UAV can not only provide scientific prediction information for driving safety,but also provide relatively accurate material consumption for road repair.
基金National Natural Science Foundation of China,No.41471145National Social Science Foundation of China,No.41201169Key Discipline of Hunan Province Geography Construction Project,No.2011001
文摘Optimizing rural settlements is an important measure to cope with rural decline, and improve the quality of rural life and attractions. This study introduces the "life quality theory". Based on the mechanisms governing the interactions between rural settlement space and life quality, this study examines how to optimize the spatial organization of rural settlements. Three aspects are evaluated – the integration of rural settlement spatial functions, optimization of spatial structure, and regulation of spatial scale – with the objective of building an optimization mode and framework for the spatial organization of rural settlements with high life quality. Our results suggest the following:(1) The settlement is the spatial carrier of life quality, which is an essential settlement component, and these two aspects influence and improve each other. Therefore, reasonable rural settlement space is an important precondition for higher life quality.(2) The spatial function types of rural settlements can be divided into those that maintain livelihoods, develop industry, and upgrade life quality. Optimizing spatial organization of rural settlements based on life quality requires promoting the maintenance of livelihood, integration of industrial development, and implantation in quality improvement.(3) There are two important components of optimizing the spatial organization of rural settlements. One is promoting the organic concentration of living, agricultural, and industrial spaces, the reasonable distribution of social intercourse, recreational, and services spaces, and the organic balance of living, production, and ecological spaces, so as to reasonably optimize the combination of internal spatial types in settlements. The other is forming a functional structure level of a "comprehensive village–featured village" and building spatial organization settlement modes connected by rural roads by relocating and adjusting the function of villages. These changes would require the destruction of underdeveloped villages, retaining normal villages, enlarging important villages, and constructing new villages.(4) As an ideal mode for optimizing rural settlements space based on life quality, the Rural Road-Oriented Development Model(RROD model) should be built at a rational scale for unit settlement and distance between settlements, leading to a fully functional RROD system with rational structure, auxiliary facility, and well-organized distribution.
基金National Natural Science Foundation of China,No.42001205,No.41971224。
文摘Rural gentrification is deeply characterized by institutional context and spatiotemporal heterogeneity.Based on a diachronic field investigation,this paper constructs an analytical framework for gentrifying rural community development(GRCD)with a“community”theoretical perspective and analytical approach,defines the concept of GRCD,and analyzes the main characteristics,formation mechanism and regulation path of a typical gentrifying rural community in the Panyang River Basin of Bama County,Guangxi.Driven by factors such as the complex flow and heterogeneous living space practices of the host-guest community,the longevity“myth”led by commercial capital and consumption demand,and multiple action logics and desertification community governance,great changes have occurred in the social space and material landscape of the rural longevity community.Such changes include comprehensive reconstruction of the resident population,surface interaction and social separation of the host-guest community,residential structure change and settlement landscape renewal,and delocalization of the healing landscape and lifestyle changes.We propose policy insights in three areas:public and localization institutional arrangements,shared and comfortable gentrifying rural community making,and inclusive and synergistic gentrifying rural community governance.Through these aspects,we provide insights from the Chinese case for the gentrification and community development of rural areas in the Global South.
基金The Construction Program for First-Class Disciplines of Hunan Province,No.5010002Education Department Research Project of Hunan Province,No.20B362。
文摘Since 2007,the Chinese government has initiated the building of national eco-cultural protection areas(NECPAs),thereby embarking on a significant transformation of the model of intangible cultural heritage(IC H)protection in China.To understand the origin and outputs of this policy,this paper demonstrates the context of China's NECPAs.It proposes a conceptual NECPA framework that mainly features regional overall ICH protection.This is followed by an examination of the case of Xiangxi in Western Hunan as a pilot zone for China’s eco-cultural protection.Xiangxi has performed much related work to promote NECPAs and made great progress in regional overall ICH protection.This insight suggests that there are benefits and costs associated with promotion of China's NECPAs and regional overall ICH protection.Despite the advantages of institutional innovation,the unexpected side effects actually undermine the success of plan implementation.
