Quantifying urbanization levels on the Tibetan Plateau with high-resolution nighttime light data

The Tibetan Plateau(TP)is undergoing rapid urbanization.To improve urban sustainability and construct eco-logical security barriers,it is essential to quantify the spatial patterns of urbanization level on the TP,but the existing studies on the topic have been limited by the lack of socioeconomic data.This study aims to quantify the urbanization level on the TP in 2018 with Luojia1-01(LJ1-01)high-resolution nighttime light(NTL)data.Specifically,the compounded night light index is used to quantify spatial patterns of urbanization level at mul-tiple scales.The results showed that the TP had a low overall urbanization level with a large internal difference.The urbanization level in the northeast,southeast and south of the TP was relatively high,forming three hotspots centered in Xining City,Lhasa City and Shangri-La City,while the urbanization level in the central and western regions was relatively low.The analysis of influencing factors,based on the random forest model,showed that transportation and topography were the main factors affecting the TP’s spatial patterns of urbanization level.The comparison analysis with socioeconomic statistics and traditional NTL data showed that LJ1-01 NTL data can be used to more effectively quantify the urbanization level since it is more advantageous for reflecting the spatial extent of urban land and describing the spatial structure of socioeconomic activities within urban areas.These advantages are attributed to the high spatial resolution of the data,appropriate imaging time and unaf-fected by saturation phenomena.Thus,the proposed LJ1-01 NTL-based urbanization level measurement method has the potential for wide applications around the world,especially in less-developed regions lacking statistical data.Using this method,we refined the measurement of the TP’s urbanization level in 2018 for multiple scales including the region,basin,prefecture and county levels,which provides basic information for the further urban sustainability research on the TP.

Spatial Patterns of LULC and Driving Forces in the Transnational Area of Tumen River:A Comparative Analysis of the Sub-regions of China,the DPRK,and Russia

Understanding the spatial patterns of land-use and land-cover(LULC)and their driving forces in transnational areas is important for the sustainable development of these regions.However,the spatial patterns of LULC and their driving forces across multiple scales are poorly understood in transnational areas.In this study,we analyzed the spatial patterns of LULC and driving forces in the transnational area of Tumen River(TATR)in 2016 across two scales:the entire region and the sub-regions of China,the Democratic People’s Republic of Korea(DPRK),and Russia.Results showed that the LULC was dominated by broadleaf forest and dry farmland in the TATR in 2016,which accounted for 66.86%and 13.60%of the entire region,respectively.Meanwhile,the LULC in the three sub-regions exhibited noticeable differences.In the Chinese and the DPRK’s sub-regions,the area of broadleaf forest was greater than those for the other LULC types,while the Russian sub-region was dominated by broadleaf forest and grassland.The spatial patterns of LULC were mainly influenced by topography,climate,soil properties,and human activities.In addition,the driving forces of the spatial patterns of LULC in the TATR had an obvious scaling effect.Therefore,we suggest that effective policies and regulations with cooperation among China,the DPRK,and Russia are needed to plan the spatial patterns of LULC and improve the sustainable development of the TATR.

Social-ecological transformations of Inner Mongolia:a sustainability perspective

Introduction:Sustainability requires the reconciling of human needs with the healthy natural ecosystem,which should be achieved within the grand course of industrialization and modernization.Systematic transitions on demography,economy,technology,and institutions are required,while different civilizations may take their respective paths.In this study,we analyze the social-ecological transitions of Inner Mongolia Autonomous Region of China during the past century,focusing on major changes in its environmental,demographic,and socioeconomic conditions.Results:A two-level social-ecological system analysis framework was proposed,and four stages of transition were identified:traditional nomadism,primitive industrial civilization,collectivization era,and economic reform/opendoor policy era.Our analysis showed that Inner Mongolia has made great achievements in its socioeconomic domains but is faced with numerous challenging environmental problems.Overconsumption of resources and failure to curtail ecological degradation may lead to a trap of unsustainability.Conclusions:However,the slowing-down population growth,improvements of the economic structure,and many new sustainability initiatives and strong support from the central government together give hope for a sustainable future of the region.

Plant community dynamics during the growing season of typical ecosystems on the Tibetan Plateau

The relationships between vegetation and environmental factors have always been a core concern of ecologists.The dynamic characteristics of plant communities during the growing season can directly reflect these relation-ships,so we examined this issue for three typical ecosystems on the Tibetan Plateau.During the growing season,the dominant species remained stable while non-dominant species changed significantly in the alpine meadow and alpine steppe and a mono-dominant community was found in the temperate desert shrub.Due to the seasonal variations of temperature and soil water content,plant species diversity varied significantly during the growing season.Patrick richness,Pielou evenness and Simpson diversity indices differed significantly in the alpine meadow and alpine steppe.The total biomass of these three ecosystems was the largest during the middle growing season.Biomass was greater in the alpine meadow than the alpine steeps or temperature desert.The root-to-shoot ratio was the lowest during the middle growing season for the alpine meadow and alpine steppe and largest during the early growing season for temperate desert shrub.RDA showed the belowground and total biomass were greatly affected by soil physicochemical factors.Multiple linear stepwise regression showed the above ground biomass was greatly affected by relative atmospheric humidity and belowground and total biomass were greatly affected by soil organic carbon,total nitrogen at 0-20 cm soil depth and pH at 10-20 cm soil depth.These findings pro-vide insights into understanding the relationships between vegetation and environmental factors and promote the sustainable utilization of local grasslands on the Tibetan Plateau.

Improving herdsmen’s well-being through scenario planning:A case study in Xilinhot City,Inner Mongolia Autonomous Region

Grassland ecosystems support well-being with food,shelter,income,and culture of herdsmen.While the associa-tion between ecosystem services and human well-being has been widely studied,such association is understudied in grassland ecosystems.This study aims to fill this gap through a case study of Xilinhot City,Inner Mongolia Autonomous Region,China.We examined the association between grassland provisioning services and herds-men’s well-being between 1985 and 2015 through participatory observations,interviews,surveys,and Bayesian belief network modeling.Considering the uncertainties of weather and sheep prices,we developed four scenarios to examine the future well-being of herdsmen.Our results show that the most important factor for herdsmen’s well-being was income,which is highly sensitive to the market price of sheep and precipitation.Considering the uncertainties of sheep prices and precipitation,scenario analysis revealed a divergence between income and well-being.While herdsmen’s income is most likely to increase with low precipitation and increased sheep prices,their well-being is most likely to improve with abundant precipitation and increased sheep prices.Based on our find-ings,we argue that developing alternative income sources(e.g.,tourism),reducing dependence on government subsidies through commercial insurance,and branding lamb with grassland ecosystem to alleviate the impact of price fluctuations would help improve herdsmen’s well-being in all scenarios.

1990-2018年土地利用/覆盖变化研究的特征和进展

Land use/cover change(LUCC)is the foundation and frontier for integrating multiple land surface processes.This paper aims to systematically review LUCC research from 1990 to 2018.Based on qualitative and quantitative analyses,we delineated the history of LUCC research and summarized their characteristics and major progress at different stages.We also identified the main challenges and proposed future directions for LUCC research.We found that the number of publications on LUCC research and their total citations grew exponentially.The research foci shifted from the process of LUCC during 1990-2004 to the impact of LUCC during 2005-2013 and then to the sustainability of LUCC from 2014 onwards.Currently,LUCC research is facing theoretical,methodological and practical challenges ranging from integrating the framework of sustainability science,adopting emerging technologies to supporting territorial spatial planning.To move forward,LUCC research should be closely integrated with landscape sustainability science and geodesign and take the leading role in territorial spatial planning to achieve the related Sustainable Development Goals.

Rapid Urban Land Expansion in Earthquake-Prone Areas of China

A timely understanding of urban expansion in earthquake-prone areas is crucial for earthquake risk assessment and urban planning for earthquake mitigation.However, a comprehensive evaluation of urban expansion in earthquake-prone areas is lacking in China, especially in the context of rapid urbanization. Based on time series urban land data and seismic ground-motion parameter zonation maps, this study analyzed urban expansion in the most seismically hazardous areas(MSHAs) of China from1992 to 2015 on the national, regional, and city scales. The results show that urban land area in the MSHAs expanded by 6767 km^2 from 1992 to 2015, with a gain of 350%.Specifically, the increase in urban land area of small cities in the MSHAs of western China during this period was the fastest, 6.24 times greater than that at the national level. In terms of spatial patterns, the urban land patches in the MSHAs in 2015 were more fragmented than those in 1992 on all scales. The percentage of change in the number of patches and the landscape shape index of the urban land patches of small cities in the MSHAs of western China were the highest across all cities. Therefore, we believe that special attention should be paid to the cities in the MSHAs that exhibit the most rapid increases in both urban land area and fragmentation, especially the small cities in western China. It is imperative to integrate earthquake mitigation into the urban planning of these cities.

Modeling the spatiotemporal dynamics of electric power consumption in China' Mainland using saturation-corrected DMSP/OLS nighttime stable light data

Obtaining timely and accurate data on the spatiotemporal dynamics of electric power consumption(EPC)is crucial for the effective utilization of electric power in China.The Defense Meteorological Satellite Program’s Operational Linescan System(DMSP/OLS)nighttime stable light(NSL)data have good potential for estimating EPC effectively at large scales.However,saturated lighted pixels contained within the NSL data limit the accuracy of EPC estimation.We developed a new method to correct the saturated lighted pixels,using the SPOT VEGETATION(SPOT/VGT)10-day synthesis product(S10)normalized differ-ence vegetation index(NDVI)data and then modeled the spatiotemporal dynamics of EPC in China' Mainland from 2000 to 2008.The results demon-strated the reliability of our approach with an average Rvalue of 0.93(P<0.001)and an average relative error of-28.92%.EPC in China' Mainland showed an average annual growth rate of 13.46% during the study period from 1198.23 billion kWh in 2000 to 3290.51 billion kWh in 2008.EPC in China' Mainland also showed clear regional variation.Northern coastal China and eastern coastal China consumed 37.61%of the total EPC in China' Mainland,with only 25.96% of the population and 6.11% of the area.

中国农村2000-2014年贫困动态——基于贫困距离指数的多尺度分析（英文）

As the largest developing country in the world, China's rural areas face many poverty-related issues. It is imperative to assess poverty dynamics in a timely and effective manner in China's rural areas. Therefore, we used the poverty gap index to investigate the poverty dynamics in China's rural areas during 2000–2014 at the national, contiguous poor areas with particular difficulties and county scales. We found that China made significant achievements in poverty alleviation during 2000–2014. At the national scale, the number of impoverished counties decreased by 1428, a reduction of 97.28%. The rural population in impoverished counties decreased by 493.94 million people or 98.76%. Poverty alleviation was closely associated with economic development, especially with industrial development. Among all 15 socioeconomic indicators, the industrial added value had the highest correlation coefficient with the poverty gap index(r = –0.458, p<0.01). Meanwhile, the inequality of income distribution in the out-of-poverty counties has been aggravated. The urban-rural income gap among the out-of-poverty counties increased by 1.67-fold, and the coefficient of variation in rural per-capita income among the out-of-poverty counties also increased by 9.09%. Thus, we argued that special attention should be paid to reducing income inequality for sustainable development in China's rural areas.

Spatial patterns of net primary productivity and its driving forces:a multi-scale analysis in the transnational area of the Tumen River

Analyzing the spatial patterns of net primary productivity(NPP)and its driving forces in transnational areas provides a solid basis for understanding regional ecological processes and ecosystem services.However,the spatial patterns of NPP and its driving forces have been poorly understood on multiple scales in transnational areas.In this study,the spatial patterns of NPP in the transnational area of the Tumen River(TATR)in 2016 were simulated using the Carnegie Ames Stanford Approach(CASA)model,and its driving forces were analyzed using a stepwise multiple linear regression model.We found that the total amount of NPP in the TATR in 2016 was approximately 14.53 TgC.The amount of NPP on the Chinese side(6.23 TgC)was larger than those on the other two sides,accounting for 42.88%of the total volume of the entire region.Among different land-use and land-cover(LULC)types,the amount of NPP of the broadleaf forest was the largest(11.22 TgC),while the amount of NPP of the bare land was the smallest.The NPP per unit area was about 603.21 gC/(m2 yr)across the entire region,while the NPP per unit area on the Chinese side was the largest,followed by the Russian side and the DPRK's side.The spatial patterns of NPP were influenced by climate,topography,soil texture,and human activities.In addition,the driving forces of the spatial patterns of NPP in the TATR had an obvious scaling effect,which was mainly caused by the spatial heterogeneity of climate,topography,soil texture,and human activities.We suggest that effective land management policies with cooperation among China,the DPRK,and Russia are needed to maintain NPP and improve environmental sustainability in the TATR.

Spatial heterogeneity of urban soils:the case of the Beijing metropolitan region,China

Introduction:Urban soils are large pools of carbon,nitrogen,and other elements,supporting plant growth,sustaining biogeochemical cycles,and serving as the foundation for maintaining ecosystem function and services of urban green spaces(UGS).Quantifying urban soil properties is essential for assessing urban ecosystem services and detecting pollution.Characterizing spatial heterogeneity of urban soil properties,which may change with land use or urbanization,is crucial for understanding urban ecosystem functions.Methods:We collected 466 soil composite samples across the Beijing metropolitan region and then analyzed the heterogeneity of soil properties in UGS of Beijing metropolitan region by ANOVA along the urbanization gradient spanning different land uses.Results:Our results show that soil properties vary considerably among land-use types and along the urban-rural gradient.Soil moisture content,soil organic carbon(SOC),available phosphorus,available potassium,total nitrogen(TN),the ratio of SOC:TN(C/N),Pb,and Cu increased notably from suburbs to the urban core,while soil pH,bulk density,TN,Cr,Ni,and Mn were not significantly different across urbanization levels.Most soil properties,except soil TN,Cu,Cr,Ni,exhibited significant differences between different land uses.The highest levels of soil nutrients and heavy metals were found in roadsides and residential areas among all the land uses.Conclusions:The spatial heterogeneity of urban soils in the Beijing metropolitan region is mainly attributable to the different land uses.Soil nutrient content has increased in UGS due to fertilization and pollution.Contamination of urban soils by heavy metals is due largely to traffic emissions and pollution by industrial and household wastes.Although human activities tend to augment urban soil nutrient pools to maximize certain ecosystem services,they may inadvertently compromise these and other services by increasing pollution.Knowledge of urban soil spatial heterogeneity in UGS is indispensable for improving urban ecosystem management.

Similarities and differences of city-size distributions in three main urban agglomerations of China from 1992 to 2015： A comparative study based on nighttime light data

Comparing the city-size distribution at the urban agglomeration（UA） scale is important for understanding the processes of urban development. However, comparative studies of city-size distribution among China＇s three largest UAs, the Beijing-Tianjin-Hebei agglomeration（BTHA）, the Yangtze River Delta agglomeration（YRDA）, and the Pearl River Delta agglomeration（PRDA）, remain inadequate due to the limitation of data availability. Therefore, using urban data derived from time-series nighttime light data, the common characteristics and distinctive features of city-size distribution among the three UAs from 1992 to 2015 were compared by the Pareto regression and the rank clock method. We identified two common features. First, the city-size distribution became more even. The Pareto exponents increased by 0.17, 0.12, and 0.01 in the YRDA, BTHA, and PRDA, respectively. Second, the average ranks of small cities ascended, being 0.55, 0.08 and 0.04 in the three UAs, respectively. However, the average ranks of large and medium cities in the three UAs experienced different trajectories, which are closely related to the similarities and differences in the driving forces for the development of UAs. Place-based measures are encouraged to promote a coordinated development among cities of differing sizes in the three UAs.