Poverty has been a focus of Chinese government for a long time. It is therefore of great significance to investigate both the mechanisms and spatial patterns of regional impoverishment in order to adequately target Ch...Poverty has been a focus of Chinese government for a long time. It is therefore of great significance to investigate both the mechanisms and spatial patterns of regional impoverishment in order to adequately target Chinese anti-poverty goals. Based on the human-environment relationship and multidimensional poverty theory, this study initially develops a three-dimensional model encompassing human, society, and environmental factors to investigate the mechanisms of rural impoverishment as well as to construct an indicator system to evaluate the comprehensive poverty level(CPL) in rural areas. A back propagation neural network model was then applied to measure CPL, and standard deviation classification was used to identify counties that still require national policy-support(CRNPSs) subsequent to 2020. The results of this study suggest that CPL values conform to a decreasing trend from the southeast coast towards the inland northwest of China. Data also show that 716 CRNPSs will be present after 2020, mainly distributed in high-arid areas of the Tibetan Plateau, the transitional zones of the three-gradient terrain, as well as karst areas of southwest China. Furthermore, CRNPSs can be divided into four types, that is, key aiding counties restricted by multidimensional factors, aiding counties restricted by human development ability, aiding counties restricted by both natural resource endowment and socioeconomic development level, and aiding counties restricted by both human development ability and socioeconomic development level. We therefore propose that China should develop and adopt scientific and targeted strategies to relieve the relative poverty that still exist subsequent to 2020.展开更多
Intergovernmental Panel on Climate Change(IPCC)in 2001 reported that the Earth air temperature would rise by 1.4-5.8℃and 2.5℃on average by the year 2100.China re-gional climate model results also showed that the air...Intergovernmental Panel on Climate Change(IPCC)in 2001 reported that the Earth air temperature would rise by 1.4-5.8℃and 2.5℃on average by the year 2100.China re-gional climate model results also showed that the air temperature on the Qinghai-Tibet Plateau(QTP)would increase by 2.2-2.6℃in the next 50 years.A numerical permafrost model was developed to predict the changes of permafrost distribution on the QTP over the next 50 and 100 years under the two climatic warming scenarios,i.e.0.02℃/a,the lower value of IPCC’s estima-tion,and 0.052℃/a,the higher value predicted by Qin et al.Simulation results show that(i)in the case of 0.02℃/a air-temperature rise,permafrost area on the QTP will shrink about 8.8%in the next 50 years,and high temperature permafrost with mean annual ground temperature(MAGT)higher than?0.11℃may turn into seasonal frozen soils.In the next 100 years,perma-frost with MAGT higher than?0.5℃will disappear and the permafrost area will shrink up to 13.4%.(ii)In the case of 0.052℃/a air-temperature rise,permafrost area on the QTP will reduce about 13.5%after 50 years.More remarkable degradation will take place after 100 years,and permafrost area will reduce about 46%.Permafrost with MAGT higher than?2℃will turn into seasonal frozen soils and even unfrozen soils.展开更多
A framework for preparation of an early warning system was developed for Maryland, using a GIS database and a collective overlay of maps that highlight highway slopes susceptible to soil slides or slope failures in ad...A framework for preparation of an early warning system was developed for Maryland, using a GIS database and a collective overlay of maps that highlight highway slopes susceptible to soil slides or slope failures in advance through spatial and statistical analysis. Data for existing soil slope failures was collected from geotechnical reports and field visits. A total of 48 slope failures were recorded and analyzed. Six factors, including event precipitation, geological formation, land cover, slope history, slope angle, and elevation were considered to affect highway soil siope stability. The observed trends indicate that precipitation and poor surface or subsurface drainage conditions are principal factors causing slope failures. 96% of the failed slopes have an open drainage section. A majority of the failed slopes lie in regions with relatively high event precipitation （P 〉 200 mm）. 90% of the existing failures are surficial erosion type failures, and only 1 out of the 42 slope failures is deep rotational type failure. More than half of the analyzed slope failures have occurred in regions having low density land cover. 46% of failures are on slopes with slope angles between 20~ and 30~. Influx of more data relating to failed slopes should give rise to more trends, and thus the developed slope management system will aid the state highway engineers in prudential budget allocation and prioritizing different remediation projects based on the literature reviewed on the principles, concepts, techniques, and methodology for slope instability evaluation （Lesh- chinsky et al., 2015）.展开更多
基金National Key Research and Development Program of China,No.2017YFC0504701National Natural Science Foundation of China,No.41871183,No.41471143
文摘Poverty has been a focus of Chinese government for a long time. It is therefore of great significance to investigate both the mechanisms and spatial patterns of regional impoverishment in order to adequately target Chinese anti-poverty goals. Based on the human-environment relationship and multidimensional poverty theory, this study initially develops a three-dimensional model encompassing human, society, and environmental factors to investigate the mechanisms of rural impoverishment as well as to construct an indicator system to evaluate the comprehensive poverty level(CPL) in rural areas. A back propagation neural network model was then applied to measure CPL, and standard deviation classification was used to identify counties that still require national policy-support(CRNPSs) subsequent to 2020. The results of this study suggest that CPL values conform to a decreasing trend from the southeast coast towards the inland northwest of China. Data also show that 716 CRNPSs will be present after 2020, mainly distributed in high-arid areas of the Tibetan Plateau, the transitional zones of the three-gradient terrain, as well as karst areas of southwest China. Furthermore, CRNPSs can be divided into four types, that is, key aiding counties restricted by multidimensional factors, aiding counties restricted by human development ability, aiding counties restricted by both natural resource endowment and socioeconomic development level, and aiding counties restricted by both human development ability and socioeconomic development level. We therefore propose that China should develop and adopt scientific and targeted strategies to relieve the relative poverty that still exist subsequent to 2020.
基金the Knowledge Innovation Project of Chinese Academy of Sciences(CAS)(Grant No.KZCX1-SW-04)the Knowledge Innovation Project of CAREERI,CAS(Grant No.CACX200009)the Project of Ministry of Science and Technology of China(Grant No.G1998040812).
文摘Intergovernmental Panel on Climate Change(IPCC)in 2001 reported that the Earth air temperature would rise by 1.4-5.8℃and 2.5℃on average by the year 2100.China re-gional climate model results also showed that the air temperature on the Qinghai-Tibet Plateau(QTP)would increase by 2.2-2.6℃in the next 50 years.A numerical permafrost model was developed to predict the changes of permafrost distribution on the QTP over the next 50 and 100 years under the two climatic warming scenarios,i.e.0.02℃/a,the lower value of IPCC’s estima-tion,and 0.052℃/a,the higher value predicted by Qin et al.Simulation results show that(i)in the case of 0.02℃/a air-temperature rise,permafrost area on the QTP will shrink about 8.8%in the next 50 years,and high temperature permafrost with mean annual ground temperature(MAGT)higher than?0.11℃may turn into seasonal frozen soils.In the next 100 years,perma-frost with MAGT higher than?0.5℃will disappear and the permafrost area will shrink up to 13.4%.(ii)In the case of 0.052℃/a air-temperature rise,permafrost area on the QTP will reduce about 13.5%after 50 years.More remarkable degradation will take place after 100 years,and permafrost area will reduce about 46%.Permafrost with MAGT higher than?2℃will turn into seasonal frozen soils and even unfrozen soils.
文摘A framework for preparation of an early warning system was developed for Maryland, using a GIS database and a collective overlay of maps that highlight highway slopes susceptible to soil slides or slope failures in advance through spatial and statistical analysis. Data for existing soil slope failures was collected from geotechnical reports and field visits. A total of 48 slope failures were recorded and analyzed. Six factors, including event precipitation, geological formation, land cover, slope history, slope angle, and elevation were considered to affect highway soil siope stability. The observed trends indicate that precipitation and poor surface or subsurface drainage conditions are principal factors causing slope failures. 96% of the failed slopes have an open drainage section. A majority of the failed slopes lie in regions with relatively high event precipitation （P 〉 200 mm）. 90% of the existing failures are surficial erosion type failures, and only 1 out of the 42 slope failures is deep rotational type failure. More than half of the analyzed slope failures have occurred in regions having low density land cover. 46% of failures are on slopes with slope angles between 20~ and 30~. Influx of more data relating to failed slopes should give rise to more trends, and thus the developed slope management system will aid the state highway engineers in prudential budget allocation and prioritizing different remediation projects based on the literature reviewed on the principles, concepts, techniques, and methodology for slope instability evaluation （Lesh- chinsky et al., 2015）.
