Current Issue
2022, Volume 32, Issue 3
Display Method:
2022,
32(3):
373-388.
doi: 10.1007/s11769-022-1274-4
Abstract:
Scale is the range or measurement unit of the characteristics of natural or human ontology in the temporal or spatial dimension and is widely used in daily life and the study of various disciplines. Scale effect pertains to certain laws and characteristics that can only be reflected on a specific scale, so choosing the appropriate scale remains the basic premise of scientific research. The concept of the urban spatial system is complex and has the characteristics of scale dependence, and the selection of an appropriate spatial scale is important for the accurate estimation and description of urban issues. In this paper, we discuss spatial scale in urban research using cases that primarily come from the Chinese experience, provide some examples that demonstrate the importance of appropriate scale in urban research, including urban shrinkage, and highlight problems in spatial research. Ultimately, we suggest that scale consciousness should be the basic consciousness required in empirical research.
Scale is the range or measurement unit of the characteristics of natural or human ontology in the temporal or spatial dimension and is widely used in daily life and the study of various disciplines. Scale effect pertains to certain laws and characteristics that can only be reflected on a specific scale, so choosing the appropriate scale remains the basic premise of scientific research. The concept of the urban spatial system is complex and has the characteristics of scale dependence, and the selection of an appropriate spatial scale is important for the accurate estimation and description of urban issues. In this paper, we discuss spatial scale in urban research using cases that primarily come from the Chinese experience, provide some examples that demonstrate the importance of appropriate scale in urban research, including urban shrinkage, and highlight problems in spatial research. Ultimately, we suggest that scale consciousness should be the basic consciousness required in empirical research.
2022,
32(3):
389-404.
doi: 10.1007/s11769-022-1275-3
Abstract:
Urban shrinkage is becoming an increasingly common phenomenon in China. The research focus has been the identification, origin, and pattern of shrinking cities. Nevertheless, attention has also been paid to the problems associated with urban shrinkage. The present study examines one typical shrinking city in China, specifically the Yichun District in Yichun City. To explore the matching relationship between residential and commercial spaces, this study analyzes supply and demand data, electricity consumption data and multi-source points of interest (POI) of residents. The results showed that the occupancy rate is not reduced in the context of urban shrinkage, and that the supply level of various commercial facilities is not in decline. Apart from leisure and entertainment facilities, the supply levels of catering, shopping and supporting facilities for life were noted to have improved. In reference to urban shrinkage, the matching relationship between residential and commercial space in the 5-min, 10-min, and 15-min living circles mainly shifted to a high-level equilibrium. The matching relationships between residential space and different types of commercial spaces change in both direction and magnitude. From the perspective of supply and demand, the spatial and temporal changes in the relationship relate to multiple factors, such as the level of economic development, the buiding age pattern, public transportation accessibility, aging, and residents’ willingness to move. This study provides relevant data for managing urban shrinkage. It also helps improve the relationships between residential and commercial spaces and works to optimize the layout and structure of functional urban spaces.
Urban shrinkage is becoming an increasingly common phenomenon in China. The research focus has been the identification, origin, and pattern of shrinking cities. Nevertheless, attention has also been paid to the problems associated with urban shrinkage. The present study examines one typical shrinking city in China, specifically the Yichun District in Yichun City. To explore the matching relationship between residential and commercial spaces, this study analyzes supply and demand data, electricity consumption data and multi-source points of interest (POI) of residents. The results showed that the occupancy rate is not reduced in the context of urban shrinkage, and that the supply level of various commercial facilities is not in decline. Apart from leisure and entertainment facilities, the supply levels of catering, shopping and supporting facilities for life were noted to have improved. In reference to urban shrinkage, the matching relationship between residential and commercial space in the 5-min, 10-min, and 15-min living circles mainly shifted to a high-level equilibrium. The matching relationships between residential space and different types of commercial spaces change in both direction and magnitude. From the perspective of supply and demand, the spatial and temporal changes in the relationship relate to multiple factors, such as the level of economic development, the buiding age pattern, public transportation accessibility, aging, and residents’ willingness to move. This study provides relevant data for managing urban shrinkage. It also helps improve the relationships between residential and commercial spaces and works to optimize the layout and structure of functional urban spaces.
2022,
32(3):
405-417.
doi: 10.1007/s11769-021-1248-y
Abstract:
Population growth has been widely regarded as an important driver of surging housing prices of urban China, while it is unclear as yet whether population shrinkage has an impact on housing prices that is symmetrical with that of population growth. This study, taking 35 sample cites in Northeast China, the typical rust belt with intensifying population shrinkage, as examples, provides an empirical assessment of the roles of population growth and shrinkage in changing housing prices by analyzing panel data, as well as a variety of other factors in related to housing price, during the period of 1999–2018. Findings indicate that although gap in housing prices was widening between population growing cities and population shrinking cities, the past two decades witnessed an obvious rise in housing prices of those sample cities to varying degree. Changes in population size did not have a statistically significant impact on housing prices volatility of sample cities, because population reduction did not lead to a decline in housing demand correspondingly and an increasing housing demand aroused by population growth was usually followed by a quicker and larger housing supply. The rising housing prices in sample cities was mainly driven by factors like changes in land cost, investment in real estate, GDP per capita and household number. However, this does not mean that the impact of population shrinkage on housing prices could be ignored. As population shrinkage intensifies, avoiding the rapid decline of house prices should be the focus of real estate regulation in some population shrinking cities of Northeast China. Our findings contribute a new form of asymmetric responses of housing price to population growth and shrinkage, and offer policy implications for real estate regulation of population shrinking cities in China’s rust belt.
Population growth has been widely regarded as an important driver of surging housing prices of urban China, while it is unclear as yet whether population shrinkage has an impact on housing prices that is symmetrical with that of population growth. This study, taking 35 sample cites in Northeast China, the typical rust belt with intensifying population shrinkage, as examples, provides an empirical assessment of the roles of population growth and shrinkage in changing housing prices by analyzing panel data, as well as a variety of other factors in related to housing price, during the period of 1999–2018. Findings indicate that although gap in housing prices was widening between population growing cities and population shrinking cities, the past two decades witnessed an obvious rise in housing prices of those sample cities to varying degree. Changes in population size did not have a statistically significant impact on housing prices volatility of sample cities, because population reduction did not lead to a decline in housing demand correspondingly and an increasing housing demand aroused by population growth was usually followed by a quicker and larger housing supply. The rising housing prices in sample cities was mainly driven by factors like changes in land cost, investment in real estate, GDP per capita and household number. However, this does not mean that the impact of population shrinkage on housing prices could be ignored. As population shrinkage intensifies, avoiding the rapid decline of house prices should be the focus of real estate regulation in some population shrinking cities of Northeast China. Our findings contribute a new form of asymmetric responses of housing price to population growth and shrinkage, and offer policy implications for real estate regulation of population shrinking cities in China’s rust belt.
2022,
32(3):
418-437.
doi: 10.1007/s11769-022-1276-2
Abstract:
With the transformation of China’s industry and demographic structure, urban shrinkage, especially the resource-based cities due to their single industrial structure, tend to emerge gradually. Using empirical and quantitative methods, this paper explores the evolution mechanism of urban shrinkage in Hegang, a resource-based city in China. Our findings suggest that there are many correlations or cyclic relationships among variables, which provide an empirical confirmation for the complexity of urban shrinkage process. The result shows there is a time delay of about four to five years between the mining industry and the changes of demographic profile, economic performance and built environment variables. The development of Hegang has formed a path dependence on resource-based industries. Furthermore, the time lags between demographic profile and economic performance variables are not obvious, and the real estate market has a certain sensitivity to perceive population loss and economic change. Besides, market led public service facilities are more sensitive to the changes of population outflow and economic recession than government led public service facilities. The study findings could offer insights for other resource-based cities in developing countries to employ on the economic development policies issues.
With the transformation of China’s industry and demographic structure, urban shrinkage, especially the resource-based cities due to their single industrial structure, tend to emerge gradually. Using empirical and quantitative methods, this paper explores the evolution mechanism of urban shrinkage in Hegang, a resource-based city in China. Our findings suggest that there are many correlations or cyclic relationships among variables, which provide an empirical confirmation for the complexity of urban shrinkage process. The result shows there is a time delay of about four to five years between the mining industry and the changes of demographic profile, economic performance and built environment variables. The development of Hegang has formed a path dependence on resource-based industries. Furthermore, the time lags between demographic profile and economic performance variables are not obvious, and the real estate market has a certain sensitivity to perceive population loss and economic change. Besides, market led public service facilities are more sensitive to the changes of population outflow and economic recession than government led public service facilities. The study findings could offer insights for other resource-based cities in developing countries to employ on the economic development policies issues.
2022,
32(3):
438-455.
doi: 10.1007/s11769-022-1277-1
Abstract:
Under the demand of urban expansion and the constraints of China’s ‘National Main Functional Area Planning’ policy, urban agglomerations are facing with a huge contradiction between land utilization and ecological protection, especially for Harbin-Changchun urban agglomeration who owns a large number of land used for the protection of agricultural production and ecological function. To alleviate this contradiction and provide insight into future land use patterns under different ecological constraints’ scenarios, we introduced the patch-based land use simulation (PLUS) model and simulated urban expansion of the Harbin-Changchun urban agglomeration. After verifying the accuracy of the simulation result in 2018, we predicted future urban expansion under the constraints of three different ecological scenarios in 2026. The morphological spatial pattern analysis (MSPA) method and minimum cumulative resistance (MCR) model were also introduced to identify different levels of ecological security pattern (ESP) as ecological constraints. The predicted result of the optimal protection (OP) scenario showed less proportion of water and forest than those of natural expansion (NE) and basic protection (BP) scenarios in 2026. The conclusions are that the PLUS model can improve the simulation accuracy at urban agglomeration scale compared with other cellular automata (CA) models, and the future urban expansion under OP scenario has the least threat to the ecosystem, while the expansion under the natural expansion (NE) scenario poses the greatest threat to the ecosystem. Combined with the MSPA and MCR methods, PLUS model can also be used in other spatial simulations of urban agglomerations under ecological constraints.
Under the demand of urban expansion and the constraints of China’s ‘National Main Functional Area Planning’ policy, urban agglomerations are facing with a huge contradiction between land utilization and ecological protection, especially for Harbin-Changchun urban agglomeration who owns a large number of land used for the protection of agricultural production and ecological function. To alleviate this contradiction and provide insight into future land use patterns under different ecological constraints’ scenarios, we introduced the patch-based land use simulation (PLUS) model and simulated urban expansion of the Harbin-Changchun urban agglomeration. After verifying the accuracy of the simulation result in 2018, we predicted future urban expansion under the constraints of three different ecological scenarios in 2026. The morphological spatial pattern analysis (MSPA) method and minimum cumulative resistance (MCR) model were also introduced to identify different levels of ecological security pattern (ESP) as ecological constraints. The predicted result of the optimal protection (OP) scenario showed less proportion of water and forest than those of natural expansion (NE) and basic protection (BP) scenarios in 2026. The conclusions are that the PLUS model can improve the simulation accuracy at urban agglomeration scale compared with other cellular automata (CA) models, and the future urban expansion under OP scenario has the least threat to the ecosystem, while the expansion under the natural expansion (NE) scenario poses the greatest threat to the ecosystem. Combined with the MSPA and MCR methods, PLUS model can also be used in other spatial simulations of urban agglomerations under ecological constraints.
2022,
32(3):
456-466.
doi: 10.1007/s11769-022-1273-5
Abstract:
Urban parks are an important part of urban ecosystems and also provide recreational services for urban residents. However, it is still unclear how the recreational attractiveness of urban parks can be evaluated. In this study, 12 typical parks in Changchun, China were selected for evaluation of their recreational attractiveness. We built a recreational attractiveness evaluation system based on the analytical hierarchy process (AHP) to produce a composite evaluation index. This method included : 1) the landscape quality of the parks; 2) the recreational facilities; 3) the conditions of the area; and 4) the accessibility of the parks. Our results showed that Nanhu Park, Children’s Park, Shengli Park, and Jingyuetan Forest Park had high recreational attractiveness, whereas Linyuan Park had the lowest attractiveness among the 12 parks. These results agreed with the information obtained from a field survey of the actual recreational and revisit rates, which showed that the evaluation index is reliable. Correlation analysis showed that the landscape quality and recreational facilities of parks had a direct effect on their recreational attractiveness. A negative correlation was found between the accessibility of a park and its recreational attractiveness. We conclude that if the scenery and facilities are not as good as a visitor expects, then they may choose to visit a different park, even if it takes a longer time to reach.
Urban parks are an important part of urban ecosystems and also provide recreational services for urban residents. However, it is still unclear how the recreational attractiveness of urban parks can be evaluated. In this study, 12 typical parks in Changchun, China were selected for evaluation of their recreational attractiveness. We built a recreational attractiveness evaluation system based on the analytical hierarchy process (AHP) to produce a composite evaluation index. This method included : 1) the landscape quality of the parks; 2) the recreational facilities; 3) the conditions of the area; and 4) the accessibility of the parks. Our results showed that Nanhu Park, Children’s Park, Shengli Park, and Jingyuetan Forest Park had high recreational attractiveness, whereas Linyuan Park had the lowest attractiveness among the 12 parks. These results agreed with the information obtained from a field survey of the actual recreational and revisit rates, which showed that the evaluation index is reliable. Correlation analysis showed that the landscape quality and recreational facilities of parks had a direct effect on their recreational attractiveness. A negative correlation was found between the accessibility of a park and its recreational attractiveness. We conclude that if the scenery and facilities are not as good as a visitor expects, then they may choose to visit a different park, even if it takes a longer time to reach.
2022,
32(3):
467-479.
doi: 10.1007/s11769-022-1278-0
Abstract:
Green development is the cognition of geography to human-nature nexus under the background of the new era. As China is facing various eco-environment problems, green development has become a key approach towards ecological progress, and it is ultimately an explicit means to respond to support sustainable development in China. Quantifying green development performance is essential to track efforts towards sustainability and guide policymakers. However, applying the balanced property of ‘Economy-Ecology-Society’ of green development to its performance assessment is rarely discussed. Here we elaborated the connotation of green development and developed a quantification model with coupling coordination degree to assess green development performance of the largest old industrial base of China, Northeast China. We found that the green development performance has been improved from a score of 0.443 in 2003 to 0.530 in 2019 but the disparities of green development performance were enlarging over time, especially for the cities in Heilongjiang. A positive spatial autocorrelation phenomenon of green development performance was confirmed, and Low-Low clusters in the northeastern Heilongjiang and High-High clusters in the central-eastern Liaoning were discovered. This study suggests the need to track the spatio-temporal dynamics of green development performance to provide references for achieving sustainable development goals in northeast China and other regions.
Green development is the cognition of geography to human-nature nexus under the background of the new era. As China is facing various eco-environment problems, green development has become a key approach towards ecological progress, and it is ultimately an explicit means to respond to support sustainable development in China. Quantifying green development performance is essential to track efforts towards sustainability and guide policymakers. However, applying the balanced property of ‘Economy-Ecology-Society’ of green development to its performance assessment is rarely discussed. Here we elaborated the connotation of green development and developed a quantification model with coupling coordination degree to assess green development performance of the largest old industrial base of China, Northeast China. We found that the green development performance has been improved from a score of 0.443 in 2003 to 0.530 in 2019 but the disparities of green development performance were enlarging over time, especially for the cities in Heilongjiang. A positive spatial autocorrelation phenomenon of green development performance was confirmed, and Low-Low clusters in the northeastern Heilongjiang and High-High clusters in the central-eastern Liaoning were discovered. This study suggests the need to track the spatio-temporal dynamics of green development performance to provide references for achieving sustainable development goals in northeast China and other regions.
2022,
32(3):
480-492.
doi: 10.1007/s11769-022-1272-6
Abstract:
This study applies multi-source datasets (i.e., Baidu Heat Map data, points of interest (POIs) data, and floor area and land use data) and geographically and temporally weighted regression (GTWR) models to elaborate the spatiotemporal relationships between the built environment and urban vibrancy on both weekdays and weekends, using Guangzhou City as a case. First, we verified the spatially and temporally nonstationary nature of the built environment correlates, which have been largely ignored in previous studies based on local regression techniques. The spatially and temporally heterogeneous effects of the built environment on urban vibrancy are then presented and visualized, based on the GTWR results. We found that the elasticity of location (i.e., distance), land use mix (i.e., diversity), building intensity and numbers of POIs with various functions (i.e., density) are different across time (2-h intervals within a day) and space (grids), due to people’s everyday lifestyle, time-space constraints, and geographical context (e.g., spatial structure). The findings highlight the importance of a better understanding of the local geography on the spatiotemporal relationships for urban planners and local governments so as to put forward decision-making support for fostering and maintaining urban vibrancy.
This study applies multi-source datasets (i.e., Baidu Heat Map data, points of interest (POIs) data, and floor area and land use data) and geographically and temporally weighted regression (GTWR) models to elaborate the spatiotemporal relationships between the built environment and urban vibrancy on both weekdays and weekends, using Guangzhou City as a case. First, we verified the spatially and temporally nonstationary nature of the built environment correlates, which have been largely ignored in previous studies based on local regression techniques. The spatially and temporally heterogeneous effects of the built environment on urban vibrancy are then presented and visualized, based on the GTWR results. We found that the elasticity of location (i.e., distance), land use mix (i.e., diversity), building intensity and numbers of POIs with various functions (i.e., density) are different across time (2-h intervals within a day) and space (grids), due to people’s everyday lifestyle, time-space constraints, and geographical context (e.g., spatial structure). The findings highlight the importance of a better understanding of the local geography on the spatiotemporal relationships for urban planners and local governments so as to put forward decision-making support for fostering and maintaining urban vibrancy.
2022,
32(3):
493-505.
doi: 10.1007/s11769-022-1279-z
Abstract:
Biodiversity is vital for the integrity and stability of ecosystems and sustainable development. Karst regions of Southwest China is featured for undulating and broken karst terrain as well as high plant diversity. Land use changes induced by the growing population and expanding human settlement have threatened biodiversity preservation in this region. However, the impact of urban expansion on plant diversity remains unclear here. This study focuses on how expanding countryside landscapes affect the recovery rate of plant diversity and demonstrate how urban expansion affects plant diversity conservation in karst regions of Southwest China. In situ biodiversity investigations and multisource remote sensing images were combined to analyze the role of human settlement evolution in the conservation of plant diversity using descriptive statistics and regression analysis. Unmanned vehicle images, historical aerial photographs, and long-term remote sensing images were used to observe the human settlement pattern changes over 40 yr and found that plant diversity is restored faster in countryside ecosystems than in island ecosystems restricted by water. Forests, however, contribute the most to plant diversity conservation in both ecosystems. While the forest area is stable during urban expansion, massive forest patches play an essential role in plant diversity conservation. Arable lands and grasslands shrank but with a fragmenting trend, which was conducive to preserving plant diversity, whereas increased and regularized large patches of built-up areas were not beneficial to plant diversity. Accordingly, forest protection should be prioritized to coordinate future socioeconomic development and plant diversity conservation in karst and broader regions. Furthermore, large built-up patches should be limited, and the irregularity should be improved during urban expansion. Irregular shaped cultivated land and grassland were suggested to promote biological information exchanges as landscape corridors.
Biodiversity is vital for the integrity and stability of ecosystems and sustainable development. Karst regions of Southwest China is featured for undulating and broken karst terrain as well as high plant diversity. Land use changes induced by the growing population and expanding human settlement have threatened biodiversity preservation in this region. However, the impact of urban expansion on plant diversity remains unclear here. This study focuses on how expanding countryside landscapes affect the recovery rate of plant diversity and demonstrate how urban expansion affects plant diversity conservation in karst regions of Southwest China. In situ biodiversity investigations and multisource remote sensing images were combined to analyze the role of human settlement evolution in the conservation of plant diversity using descriptive statistics and regression analysis. Unmanned vehicle images, historical aerial photographs, and long-term remote sensing images were used to observe the human settlement pattern changes over 40 yr and found that plant diversity is restored faster in countryside ecosystems than in island ecosystems restricted by water. Forests, however, contribute the most to plant diversity conservation in both ecosystems. While the forest area is stable during urban expansion, massive forest patches play an essential role in plant diversity conservation. Arable lands and grasslands shrank but with a fragmenting trend, which was conducive to preserving plant diversity, whereas increased and regularized large patches of built-up areas were not beneficial to plant diversity. Accordingly, forest protection should be prioritized to coordinate future socioeconomic development and plant diversity conservation in karst and broader regions. Furthermore, large built-up patches should be limited, and the irregularity should be improved during urban expansion. Irregular shaped cultivated land and grassland were suggested to promote biological information exchanges as landscape corridors.
2022,
32(3):
506-520.
doi: 10.1007/s11769-022-1280-6
Abstract:
The Changtang Plateau (CTP) in Qinghai-Tibet Plateau of China is one of the top-10 uninhabited areas with the most important ecological value in the world. It is of great academic and practical significance to carry out research on human settlements in the marginal zones of the uninhabited areas to promote harmonious coexistence between humans and nature on the CTP. Using high-definition remote-sensing images to visually interpret and identify settlement-patch data, combined with field investigations, this study explores the spatial characteristics of human settlements in Shuanghu and Nyima counties and their responses to natural and socioeconomic conditions in the hinterland of the CTP. Findings reveal that the scale of human settlements on the CTP is extremely small, and density is very sparse. Settlements on the CTP primarily consist of several households, with some containing more than a dozen households, or are sub-village scale. Socioeconomic development is low and socioeconomic factors have a weak influence on the settlement layout on the CTP. Natural factors are the core elements affecting the layout of human settlements on the CTP. Settlements tend to occur on low mountains, gentle slopes, and areas with high average annual temperatures. Careful settlement site selection can help to mitigate the impact of natural disasters. To meet the needs of grazing, settlement layouts must typically have a high-quality grassland orientation. Riverbanks are key settlement areas, and settlement sites are often far away from alpine salt lakes. The characteristics of settlements on the CTP and their responses to environmental conditions significantly differ from those of human settlements in low-altitude inland areas.
The Changtang Plateau (CTP) in Qinghai-Tibet Plateau of China is one of the top-10 uninhabited areas with the most important ecological value in the world. It is of great academic and practical significance to carry out research on human settlements in the marginal zones of the uninhabited areas to promote harmonious coexistence between humans and nature on the CTP. Using high-definition remote-sensing images to visually interpret and identify settlement-patch data, combined with field investigations, this study explores the spatial characteristics of human settlements in Shuanghu and Nyima counties and their responses to natural and socioeconomic conditions in the hinterland of the CTP. Findings reveal that the scale of human settlements on the CTP is extremely small, and density is very sparse. Settlements on the CTP primarily consist of several households, with some containing more than a dozen households, or are sub-village scale. Socioeconomic development is low and socioeconomic factors have a weak influence on the settlement layout on the CTP. Natural factors are the core elements affecting the layout of human settlements on the CTP. Settlements tend to occur on low mountains, gentle slopes, and areas with high average annual temperatures. Careful settlement site selection can help to mitigate the impact of natural disasters. To meet the needs of grazing, settlement layouts must typically have a high-quality grassland orientation. Riverbanks are key settlement areas, and settlement sites are often far away from alpine salt lakes. The characteristics of settlements on the CTP and their responses to environmental conditions significantly differ from those of human settlements in low-altitude inland areas.
2022,
32(3):
521-536.
doi: 10.1007/s11769-022-1281-5
Abstract:
With an increase in population and economic development, water withdrawals are close to or even exceed the amount of water available in many regions of the world. Modelling water withdrawals could help water planners improve the efficiency of water use, water resources allocation, and management in order to alleviate water crises. However, minimal information has been obtained on how water withdrawals have changed over space and time, especially on a regional or local scale. This research proposes a data-driven framework to help estimate county-level distribution of water withdrawals. Using this framework, spatial statistical methods are used to estimate water withdrawals for agricultural, industrial, and domestic purposes in the Huaihe River watershed in China for the period 1978–2018. Total water withdrawals were found to have more than doubled, from 292.55 × 108 m3 in 1978 to 642.93 × 108 m3 in 2009, and decreased to 602.63 × 108 m3 in 2018. Agricultural water increased from 208.17 × 108 m3 in 1978 to 435.80 × 108 m3 in 2009 and decreased to 360.84 × 108 m3 in 2018. Industrial and domestic water usage constantly increased throughout the 1978–2018 period. In 1978, industrial and domestic demands were 20.35 × 108 m3 and 60.04 × 108 m3, respectively, and up until 2018, the figures were 105.58 × 108 m3 and 136.20 × 108 m3. From a spatial distribution perspective, Moran’s I statistical results show that the total water withdrawal has significant spatial autocorrelation during 1978–2018. The overall trend was a gradual increase in 1978–2010 with withdrawal beginning to decline in 2010–2018. The results of Getis-Ord Gi* statistical calculations showed spatially contiguous clusters of total water withdrawal in the Huaihe River watershed during1978–2010, and the spatial agglomeration weakened from 2010 to 2018. This study provides a data-driven framework for assessing water withdrawals to enable a deeper understanding of competing water use among economic sectors as well as water withdrawal modelled with proper data resource and method.
With an increase in population and economic development, water withdrawals are close to or even exceed the amount of water available in many regions of the world. Modelling water withdrawals could help water planners improve the efficiency of water use, water resources allocation, and management in order to alleviate water crises. However, minimal information has been obtained on how water withdrawals have changed over space and time, especially on a regional or local scale. This research proposes a data-driven framework to help estimate county-level distribution of water withdrawals. Using this framework, spatial statistical methods are used to estimate water withdrawals for agricultural, industrial, and domestic purposes in the Huaihe River watershed in China for the period 1978–2018. Total water withdrawals were found to have more than doubled, from 292.55 × 108 m3 in 1978 to 642.93 × 108 m3 in 2009, and decreased to 602.63 × 108 m3 in 2018. Agricultural water increased from 208.17 × 108 m3 in 1978 to 435.80 × 108 m3 in 2009 and decreased to 360.84 × 108 m3 in 2018. Industrial and domestic water usage constantly increased throughout the 1978–2018 period. In 1978, industrial and domestic demands were 20.35 × 108 m3 and 60.04 × 108 m3, respectively, and up until 2018, the figures were 105.58 × 108 m3 and 136.20 × 108 m3. From a spatial distribution perspective, Moran’s I statistical results show that the total water withdrawal has significant spatial autocorrelation during 1978–2018. The overall trend was a gradual increase in 1978–2010 with withdrawal beginning to decline in 2010–2018. The results of Getis-Ord Gi* statistical calculations showed spatially contiguous clusters of total water withdrawal in the Huaihe River watershed during1978–2010, and the spatial agglomeration weakened from 2010 to 2018. This study provides a data-driven framework for assessing water withdrawals to enable a deeper understanding of competing water use among economic sectors as well as water withdrawal modelled with proper data resource and method.
2022,
32(3):
537-548.
doi: 10.1007/s11769-022-1282-4
Abstract:
In the present work, 15 400 yr old geochemical records of a core from the subalpine Daping swamp are presented with the aim to examine the relationship between the chemical weathering and the climatic changes in the region of the western Nanling Mountains, China. The climate of the study region was deeply controlled by the East Asian summer monsoon. The results indicate that, in the past 15 400 yrs, the values of chemical index of alteration (CIA) ranged from 73.9% to 88.2% (mean: 85.3%), suggested a medium and high intensity of chemical weathering. The local exogenous clastic materials, which were derived from the weathered residues, played a key role in contributing towards the sediments. Since the climate-induced chemical weathering exerted strong influences on the geochemical features of weathered residues, the geochemical characteristics of the sediments were deeply impacted by climatic conditions. Wetter and warmer conditions would favor increased chemical weathering, resulting in more leaching of soluble and mobile elements (e.g., Ba and Sr) and leaving the resistant and immobile elements (e.g., Al and Ti) enriched in the weathered residues. These materials were then eroded and transported into the lake, and led to the sediments characterized by the characteristic of having depleted soluble elements. In contrast, dry and cold conditions would result in an opposite trend. In this sense, the geochemical records can serve as proxies to indicate changes of chemical weathering intensity, which were closely related to the evolution of summer monsoon.
In the present work, 15 400 yr old geochemical records of a core from the subalpine Daping swamp are presented with the aim to examine the relationship between the chemical weathering and the climatic changes in the region of the western Nanling Mountains, China. The climate of the study region was deeply controlled by the East Asian summer monsoon. The results indicate that, in the past 15 400 yrs, the values of chemical index of alteration (CIA) ranged from 73.9% to 88.2% (mean: 85.3%), suggested a medium and high intensity of chemical weathering. The local exogenous clastic materials, which were derived from the weathered residues, played a key role in contributing towards the sediments. Since the climate-induced chemical weathering exerted strong influences on the geochemical features of weathered residues, the geochemical characteristics of the sediments were deeply impacted by climatic conditions. Wetter and warmer conditions would favor increased chemical weathering, resulting in more leaching of soluble and mobile elements (e.g., Ba and Sr) and leaving the resistant and immobile elements (e.g., Al and Ti) enriched in the weathered residues. These materials were then eroded and transported into the lake, and led to the sediments characterized by the characteristic of having depleted soluble elements. In contrast, dry and cold conditions would result in an opposite trend. In this sense, the geochemical records can serve as proxies to indicate changes of chemical weathering intensity, which were closely related to the evolution of summer monsoon.
Email
RSS