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    Spatial-temporal Dynamics and Driving Forces of Land Development Intensity in the Western China from 2000 to 2015
    HUANG Xin, HUANG Xiaojun, LIU Mengmeng, WANG Bo, ZHAO Yonghua
    中国地理科学    2020, 30 (1): 16-29.   DOI: 10.1007/s11769-020-1095-2
    摘要402)      PDF (5745KB)(486)   
    The change in land development intensity is an important perspective to reflect the variation in regional social and economic development and spatial differentiation. In this paper, spatial statistical analysis, Ordinary Least Squares (OLS), and Geographically weighted regression (GWR) methods are used to systematically analyse the spatial-temporal characteristics and driving forces of land development intensity for 131 spatial units in the western China from 2000 to 2015. The findings of the study are as follows:1) The land development intensity in the western China has been increasing rapidly. From 2000 to 2015, land development intensity increased by 3.4 times on average. 2) The hotspot areas have shifted from central Inner Mongolia, northern Shaanxi and the Beibu Gulf of Guangxi to the Guanzhong Plain and the Chengdu-Chongqing urban agglomeration. The areas of cold spots were mainly concentrated in the Qinghai-Tibet Plateau, Yunnan, and Xinjiang. 3) Investment intensity and the natural environment have always been the main drivers of land development intensity in the western China. Investment played a powerful role in promoting land development intensity, while the natural and ecological environment distinctly constrained such development. The effect of the economic factors on land development intensity in the western China has changed, which is reflected in the driving factor of construction land development shifting from economic growth in 2000 to economic structure, especially industrial structure, in 2015.
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    Responses of Alpine Wetlands to Climate Changes on the Qinghai-Tibetan Plateau Based on Remote Sensing
    WANG Rui, HE Min, NIU Zhenguo
    中国地理科学    2020, 30 (2): 189-201.   DOI: 10.1007/s11769-020-1107-2
    摘要304)      PDF (1759KB)(509)   
    The alpine wetlands in QTP (Qinghai-Tibetan Plateau) have been profoundly impacted along with global climate changes. We employ satellite datasets and climate data to explore the relationships between alpine wetlands and climate changes based on remote sensing data. Results show that:1) the wetland NDVI (Normalized Difference Vegetation Index) and GPP (Gross Primary Production) were more sensitive to air temperature than to precipitation rate. The wetland ET (evapotranspiration) across alpine wetlands was greatly correlated with precipitation rate. 2) Alpine wetlands responses to climate changes varied spatially and temporally due to different geographic environments, variety of wetland formation and human disturbances. 3) The vegetation responses of the Zoige wetland was the most noticeable and related to the temperature, while the GPP and NDVI of the Qiangtang Plateau and Gyaring-Ngoring Lake were significantly correlated with both temperature and precipitation. 4) ET in the Zoige wetland showed a significantly positive trend, while ET in Maidika wetland and the Qiangtang plateau showed a negative trend, implying wetland degradation in those two wetland regions. The complexities of the impacts of climate changes on alpine wetlands indicate the necessity of further study to understand and conserve alpine wetland ecosystems.
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    A Synthesizing Land-cover Classification Method Based on Google Earth Engine: A Case Study in Nzhelele and Levhuvu Catchments, South Africa
    ZENG Hongwei, WU Bingfang, WANG Shuai, MUSAKWA Walter, TIAN Fuyou, MASHIMBYE Zama Eric, POONA Nitesh, SYNDEY Mavengahama
    中国地理科学    2020, 30 (3): 397-409.   DOI: 10.1007/s11769-020-1119-y
    摘要297)      PDF (3308KB)(795)   
    This study designed an approach to derive land-cover in the South Africa with insufficient ground samples, and made a case demonstration in Nzhelele and Levhuvu catchments, South Africa. The method was developed based on an integration of Landsat 8, Sentinel-1, and Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM), and the Google Earth Engine (GEE) platform. Random forest classifier with 300 trees is employed as land-cover classification model. In order to overcome the defect of insufficient ground data, the stratified sampling method was used to generate the training and validation samples from the existing land-cover product. Likewise, in order to recognize different land-cover categories, the percentile and monthly median composites were employed to expand input metrics of random forest classifier. Results showed that the overall accuracy of the land-cover of Nzhelele and Levhuvu catchments, South Africa in 2017-2018 reached to 76.43%. Three important results can be drawn from our research. 1) The participation of Sentinel-1 data can slightly improve overall accuracy of land-cover while its contribution on land-cover classification varied with land types. 2) Under-fitting problem was observed in the training of non-dominant land-cover categories using the random sampling, the stratified sampling method is recommended to make sure the classification accuracy of non-dominant classes. 3) When related reflectance bands participated in the training process, individual Normalized Difference Vegetation index (NDVI), Enhanced Vegetation Index (EVI), Soil Adjusted Vegetation Index (SAVI), Normalized Difference Built-up Index (NDBI) have little effect on final land-cover classification result.
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    Spatial and Temporal Changes of Arable Land Driven by Urbanization and Ecological Restoration in China
    WANG Liyan, ANNA Herzberger, ZHANG Liyun, XIAO Yi, WANG Yaqing, XIAO Yang, LIU Jianguo, OUYANG Zhiyun
    中国地理科学    2019, 20 (5): 809-819.   DOI: 10.1007/s11769-018-0983-1
    摘要256)      PDF (781KB)(433)   

    Since the industrial revolution, human activities have both expanded and intensified across the globe resulting in accelerated land use change. Land use change driven by China's development has put pressure on the limited arable land resources, which has affected grain production. Competing land use interests are a potential threat to food security in China. Therefore, studying arable land use changes is critical for ensuring future food security and maintaining the sustainable development of arable land. Based on data from several major sources, we analyzed the spatio-temporal differences of arable land among different agricultural regions in China from 2000 to 2010 and identified the drivers of arable land expansion and loss. The results revealed that arable land decreased by 5.92 million ha or 3.31%. Arable land increased in the north and decreased in the south of China. Urbanization and ecological restoration programs were the main drivers of arable land loss, while the reclamation of other land cover types (e.g., forest, grassland, and wetland) was the primary source of the increased arable land. The majority of arable land expansion occurred in the Northwest, but the centroid for grain production moved to northeast, which indicated that new arable land was of poor quality and did not significantly contribute to the grain production capacity. When combined with the current ‘Red Line of Arable Land Policy’ (RAL) and ‘Ecological Redline Policy’ (EPR), this study can provide effective information for arable land policymaking and help guide the sustainable development of arable land.

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    Spatial Characteristics and Influencing Factors of Urban Resilience from the Perspective of Daily Activity: A Case Study of Nanjing, China
    SUN Honghu, ZHEN Feng
    中国地理科学    2021, 31 (3): 387-399.   DOI: 10.1007/s11769-021-1201-0
    摘要251)      PDF (5642KB)(194)   
    Based on the connotation of urban resilience and the main contradictions of China’s urbanization, urban resilience is placed within the main daily activities contradictory scene of the urban man-land system to build a theoretical framework of urban activity resilience. Relying on geographic big data, this study identifies the spatial characteristics of activity resilience, reveals the impact of activity environment on activity resilience in Nanjing, and proposes countermeasures. The main conclusions are as follows. 1) Activity resilience presents a composite spatial structure of circles and clusters, and most areas are resilient but at a low level. 2) There are significantly positive and negative global autocorrelation between activity resilience and activity scale, and activity stability. Simultaneously, there also exists a local spatial autocorrelation with the opposite positive and negative trends. 3) Activity environment has a significant effect on activity resilience, and the degree and direction of influence among different dimensions and regions are heterogeneous. 4) For activity resilience, it is necessary to increase the matching degree between the scale and stability of activities, and reduce the excessive concentration and flow of activities. For the activity environment, it is necessary to improve the accessibility of the ecological environment, strengthen the high-quality supply of the infrastructure environment, optimize the balance of the location environment, and promote the inclusiveness of the social environment.
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    Monitoring Intra-annual Spatiotemporal Changes in Urban Heat Islands in 1449 Cities in China Based on Remote Sensing
    LI Yuanzheng, WANG Lan, ZHANG Liping, LIU Min, ZHAO Guosong
    中国地理科学    2019, 29 (6): 905-916.   DOI: 10.1007/s11769-019-1080-9
    摘要245)      PDF (1642KB)(366)   

    This study aimed to accurately study the intra-annual spatiotemporal variation in the surface urban heat island intensities (SUHIIs) in 1449 cities in China. First, China was divided into five environmental regions. Then, the SUHIIs were accurately calculated based on the modified definitions of the city extents and their corresponding nearby rural areas. Finally, we explored the spatiotemporal variation of the mean, maximum, and minimum values, and ranges of SUHIIs from several aspects. The results showed that larger annual mean daytime SUHIIs occurred in hot-humid South China and cold-humid northeastern China, and the smallest occurred in arid and semiarid west China. The seasonal order of the SUHIIs was summer > spring > autumn > winter in all the temperate regions except west China. The SUHIIs were obviously larger during the rainy season than the dry season in the tropical region. Nevertheless, significant differences were not observed between the two seasons within the rainy or dry periods. During the daytime, the maximum SUHIIs mostly occurred in summer in each region, while the minimum occurred in winter. A few cold island phenomena existed during the nighttime. The maximum SUHIIs were generally significantly positively correlated with the minimum SUHIIs during the daytime, nighttime and all-day in all environmental regions throughout the year and the four seasons. Moreover, significant correlation scarcely existed between the daytime and nighttime ranges of the SUHIIs. In addition, the daytime SUHIIs were also insignificantly correlated with the nighttime SUHIIs in half of the cases.

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    Spatiotemporal Variations and Regional Transport of Air Pollutants in Two Urban Agglomerations in Northeast China Plain
    LI Xiaolan, HU Xiaoming, SHI Shuaiyi, SHEN Lidu, LUAN Lan, MA Yanjun
    中国地理科学    2019, 29 (6): 917-933.   DOI: 10.1007/s11769-019-1081-8
    摘要241)      PDF (2401KB)(482)   

    Characteristics of air pollution in Northeast China (NEC) received less research attention in the past comparing to other heavily polluted regions in China. Spatiotemporal variations of six criteria air pollutants (PM10, PM2.5, SO2, NO2, O3 and CO) in Central Liaoning Urban Agglomeration (CLUA) and Harbin-Changchun Urban Agglomeration (HCUA) in NEC Plain were analyzed in this study based on three-year hourly observations of air pollutants and meteorological variables from 2015 to 2017. The results indicated that the annual mean concentrations of air pollutants are generally higher in the middle and southern regions in NEC Plain and lower in the northern region. Megacities such as Shenyang, Harbin and Changchun experience severe air pollution, with a three-year averaged air quality index (AQI) larger than 80, far exceeding the daily AQI standard at the first-level of 50 in China. The annual mean PM and SO2 concentrations decrease most significantly in NEC urban agglomerations from 2015 to 2017, followed by CO and NO2, while O3 shows a slight increasing trend. All the six pollutants exhibit obvious seasonal and diurnal variations, and these variations are dictated by local emission and meteorological conditions. PM2.5 and O3 concentrations in NEC urban agglomerations strongly depend on wind conditions. High O3 concentrations at different cities usually occur in presence of strong winds but are independent on wind direction (WD), while high PM2.5 is usually accompanied by weak winds and poor dispersion condition, and sometimes also occur when the northerly or southerly winds are strong. Regional transport of air pollutants between NEC urban agglomerations is common. A severe haze event on November 1-4, 2017 is examined to demonstrate the role of regional transport on pollution.

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    Spatial and Temporal Evolution Characteristics of PM2.5 in China from 1998 to 2016
    LI Hua, TONG Helong, WU Xianhua, LU Xiaoli, MENG Shuhan
    中国地理科学    2020, 30 (6): 947-958.   DOI: 10.1007/s11769-020-1157-5
    录用日期: 2020-08-27

    摘要229)      PDF (2968KB)(294)   
    The rapid development of China's economy and urbanization has given rise to noticeable environmental problems, among which the change of air quality has received extensive attention. The panel data of PM2.5 (particles with an aerodynamic diameter of 2.5 μm or less) in 343 prefecture-level cities in China from 1998 to 2016 were statistically analyzed to reveal the characteristics of the temporal evolution and spatial variation of China's air quality in the past two decades. The results show that: 1) the overall deterioration trend of air quality is obvious throughout the country. The variation trend of PM2.5 was divided into three phases: rapid-growth phase (1998–2007), lag phase (2006–2011) and mildly-incremental phase (2012–2016), with their average growth rates of 7.19%, −3.59% and 0.52%, respectively. 2) The spatial difference of PM2.5 values in China increased significantly with time. Since 2003, the high-value area in the east has expanded rapidly, and polarization became much more pronounced. The change rate of PM2.5 is high in the east and west and low in the middle. The change rates of most areas in the west exceed more than 80%, and in the east lie somewhere between 40% and 60%. In the midlands, the change rate is not large and some regions even show a negative growth. 3) The change rate of PM2.5 is also high in areas with higher values. However, in regions where the change rate of PM2.5 is high, the value of PM2.5 is not always high. The high change rate is mainly attributable to the low base value of PM2.5 and the cities concerned belong to sensitive areas. 4) According to the PM2.5 warning index, the number of strong, medium, weak and non-warning areas in China is 45, 85, 159 and 54, respectively.
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    Population Shrinkage in Resource-dependent Cities in China: Processes, Patterns and Drivers
    LI He, Kevin LO, ZHANG Pingyu
    中国地理科学    2020, 30 (1): 1-15.   DOI: 10.1007/s11769-019-1077-4
    摘要225)      PDF (1603KB)(360)   
    Resource-dependent cities (RCs) are a vulnerable group of urban settlements that often face population shrinkage; however, population changes in RCs in China are not well understood. This study offers new insight into this matter through a robust analysis that features a longer time scale, a larger sample of RCs, and a finer unit of analysis. It finds new evidence that problems of population shrinkage in RCs are more serious than previous literature has suggested. Approximately 30% of the studied units have experienced either long-term or short-term population shrinkage, and many more are experiencing a slowing down of population growth. Problems are especially common among three types of RCs:the resource-depleted RCs, the forestry-based RCs, and RCs in Northeast China. These results underscore transition policy inadequacies in addressing population loss, and call for a more comprehensive and diversified population policy that tackles the multifaceted factors that contribute to population shrinkage, including lack of industrial support, maladjustment to market oriented reformation, poor urban environment and natural population decline.
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    Different Responses of Vegetation to Frozen Ground Degradation in the Source Region of the Yellow River from 1980 to 2018
    WANG Rui, DONG Zhibao, ZHOU Zhengchao
    中国地理科学    2020, 30 (4): 557-571.   DOI: 10.1007/s11769-020-1135-y
    摘要205)      PDF (2702KB)(220)   
    Frozen ground degradation under a warming climate profoundly influences the growth of alpine vegetation in the source region of the Qinghai-Tibet Plateau. This study investigated spatiotemporal variations in the frozen ground distribution, the active layer thickness (ALT) of permafrost (PF) soil and the soil freeze depth (SFD) in seasonally frozen soil from 1980 to 2018 using the temperature at the top of permafrost (TTOP) model and Stefan equation. We compared the effects of these variations on vegetation growth among different frozen ground types and vegetation types in the source region of the Yellow River (SRYR). The results showed that approximately half of the PF area (20.37% of the SRYR) was projected to degrade into seasonally frozen ground (SFG) during the past four decades; furthermore, the areal average ALT increased by 3.47 cm/yr, and the areal average SFD decreased by 0.93 cm/yr from 1980 to 2018. Accordingly, the growing season Normalized Difference Vegetation Index (NDVI) presented an increasing trend of 0.002/10yr, and the increase rate and proportion of areas with NDVI increase were largest in the transition zone where PF degraded to SFG (the PF to SFG zone). A correlation analysis indicated that variations in ALT and SFD in the SRYR were significantly correlated with increases of NDVI in the growing season. However, a rapid decrease in SFD (< -1.4 cm/10yr) could have reduced the soil moisture and, thus, decreased the NDVI. The NDVI for most vegetation types exhibited a significant positive correlation with ALT and a negative correlation with SFD. However, the steppe NDVI exhibited a significant negative correlation with the SFD in the PF to SFG zone but a positive correlation in the SFG zone, which was mainly limited by water condition because of different change rates of the SFD.
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    The Environmental Impacts of Informal Economies in China: Inverted U-shaped Relationship and Regional Variances
    YANG Jiangmin, TAN Yiming, XUE Desheng, HUANG Gengzhi, XING Zuge
    中国地理科学    2021, 31 (4): 585-599.   DOI: 10.1007/s11769-021-1210-z
    录用日期: 2021-04-29

    摘要199)      PDF (3560KB)(188)   
    This paper aims to the debate on the nexus between informal economies and the environment by investigating the long-term dynamic impacts of China’s informal economies on pollution and considering regional differences in informal economies’ pollution. This paper uses the Multiple Indicators Multiple Causes (MIMIC) model to estimate the size of informal economies and employs econometric models to examine their relationships to pollution based on provincial-level panel data from 2000 to 2017. The results indicate that informal economies’ effects on environmental pollution are not purely positive or negative. Rather, our model indicates that there is an inverted U-shaped relationship between informal economies and pollution in the long run in China; this means that the level of environmental pollution increases at first and then decreases with the growth of informal economies. Further analysis shows that while this inverted, U-shaped relationship is significant in different regions of China, it is affected by different environmental impact factors. The paper concludes by discussing the policy implications for environmental protection and sustainable development.
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    Siting of Dark Sky Reserves in China Based on Multi-source Spatial Data and Multiple Criteria Evaluation Method
    WEI Ye, CHEN Zuoqi, XIU Chunliang, YU Bailang, LIU Hongxing
    中国地理科学    2019, 29 (6): 949-961.   DOI: 10.1007/s11769-019-1079-2
    摘要199)      PDF (6241KB)(685)   

    With the rapid development of population and urbanization and the progress of lighting technology, the influence of artificial light sources has increased. In this context, the problem of light pollution has attracted wide attention. Previous studies have revealed that light pollution can affect biological living environments, human physical and mental health, astronomical observations and many other aspects. Therefore, organizations internationally have begun to advocate for measures to prevent light pollution, many of which are recognized by the International Dark-Sky Association (IDA). In addition to improving public awareness, legal protections, technical treatments and other means, the construction of Dark Sky Reserves (DSR) has proven to be an effective preventive measure. So far, as a pioneer practice in this field, the IDA has identified 11 DSRs worldwide. Based on the DA requirements for DSRs, this paper utilizes NPP-VIIRS nighttime light data and other multi-source spatial data to analyze possible DSR sites in China. The land of China was divided into more than ten thousand 30 km×30 km fishnets, and constraint and suitable conditions were designated, respectively, as light and cloud conditions, and scale, traffic and attractiveness conditions. Using a multiple criteria evaluation, 1443 fishnets were finally selected as most suitable sites for the construction of DSRs. Results found that less than 25% of China is not subject to light pollution, and less than 13% is suitable for DSR construction, primarily in western and northern areas, including Tibet, Xinjiang, Qinghai, Gansu and Inner Mongolia.

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    Spatial-temporal Heterogeneity of Green Development Efficiency and Its Influencing Factors in Growing Metropolitan Area: A Case Study for the Xuzhou Metropolitan Area
    QIU Fangdao, CHEN Yang, TAN Juntao, LIU Jibin, ZHENG Ziyan, ZHANG Xinlin
    中国地理科学    2020, 30 (2): 352-365.   DOI: 10.1007/s11769-020-1114-3
    摘要199)      PDF (2343KB)(202)   
    This study analyzed the spatial-temporal heterogeneity of green development efficiency and its influencing factors in the growing Xuzhou Metropolitan Area for the period 2000-2015. The slacks-based measure (SBM) model, spatial autocorrelation, and the geographically weighted regression (GWR) model were used to conduct the analysis. The conclusions were as follows:first, the overall efficiency of green development of the Xuzhou Metropolitan Area decreased, the regional differences and spatial agglomeration shrunk and differences within the region were the main contributors to the regional differences of green development efficiency. Second, the counties with high-efficiency green development were distributed along the coast, and along the routes of the Beijing-Shanghai and the Eastern Longhai railways. A developing axis of the high-efficiency counties was the main feature of the spatial pattern for green development efficiency. Third, regarding spatial correlation and green development efficiency, the High-High type counties in the Xuzhou Metropolitan Area formed a centralized distribution corridor along the inter-provincial border areas of Henan and Jiangsu, whereas the Low-Low type counties were concentrated in the external, marginal parts of the metropolitan area. Fourth, the major factors (ranked in decreasing order of impact) influencing green development efficiency were innovation, government regulations, the economic development level, energy consumption, and industrial structure. These factors exerted their influence to varying extents; the influence of the same factor had different effects in different regions and obvious spatial differences were observed for the different regions.
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    Spatial Impact of High-speed Railway on the Urban Scale: An Empirical Analysis from Northeast China
    WANG Shaobo, GUO Jianke, LUO Xiaolong, LIU Junfeng, GU Zongni
    中国地理科学    2020, 30 (2): 366-378.   DOI: 10.1007/s11769-020-1115-2
    摘要198)      PDF (2518KB)(185)   
    The emergence of rapid transit, primarily represented by high-speed railway (HSR), while reshaping the regional traffic patterns, leads to the reconstruction and redistribution of population and industry. This leads to either shrinkage or expansion of urban scale. However, research on the influence mechanisms of the urban scale has mostly concentrated on historical, economic and social factors. The influence of traffic factors is rarely mentioned in current research. Therefore, this study examines Northeast China, where the change in urban scale is most significant, to discuss the spatial impact of high-speed railway on the urban scale. This is of great significance in terms of enriching current understanding of the factors affecting the urban scale. The results included the following:1) The high-speed railway produced considerable space-time convergence effects, however, simultaneously aggravated the imbalance in traffic development in Northeast China. The increase in accessibility presents attenuation characteristics from the high-speed railway. Additionally, the high-speed railway has changed the mode of cooperation between cities in the provinces, inter-regional and inter-provincial cooperation models gradually become popular. 2) The change rate of accessibility and the urban scale present significant spatial coupling phenomena, with the change rate of the Harbin-Dalian trunk lines and its surroundings being more significant. 3) There are predominantly four modes of the influence of high-speed railway on the urban scale, which make difference city present expansion or shrinkage.
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    Spatio-temporal Pattern and Driving Forces of Comprehensive Agricultural Productivity in Jilin Province, China
    LIU Yunda, TONG Lianjun
    中国地理科学    2020, 30 (3): 493-504.   DOI: 10.1007/s11769-020-1123-2
    摘要192)      PDF (15069KB)(112)   
    Improving comprehensive agricultural productivity is an important measure to realize agricultural modernization. Based on the data from Jilin Statistical Yearbook, this study analyzed the spatial and temporal characteristics of comprehensive agricultural productivity discrepancy in the main agricultural production areas of Jilin Province, China. The comprehensive agricultural productivity of 25 county-level administrative units were evaluated by a comprehensive index system based on five aspects which included 20 indicators from 2004 to 2017. The pattern of the discrepancy was analyzed by the spatial differentiation indices and spatial convergence theory. The results were as follows:1) the overall comprehensive agricultural productivity was in a ‘W-type’ rising trend; 2) the discrepancy was in ‘inverted W-type’ trend; 3) the spatial distribution characteristics were mainly discrete plaque and ‘inverted V-type’; 4) the formation of differences was forced by a combination of internal and external driving forces. Our study demonstrates the effectiveness of rising agricultural productivity and the level of economic and social developments in different counties in Jilin Province.
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    Assessing the Dynamics of Grassland Net Primary Productivity in Re-sponse to Climate Change at the Global Scale
    LIU Yangyang, YANG Yue, WANG Qian, KHALIFA Muhammad, ZHANG Zhaoying, TONG Linjing, LI Jianlong, SHI Aiping
    中国地理科学    2019, 20 (5): 725-740.   DOI: 10.1007/s11769-019-1063-x
    摘要188)      PDF (9146KB)(395)   

    Understanding the net primary productivity (NPP) of grassland is crucial to evaluate the terrestrial carbon cycle. In this study, we investigated the spatial distribution and the area of global grassland across the globe. Then, we used the Carnegie-Ames-Stanford Approach (CASA) model to estimate global grassland NPP and explore the spatio-temporal variations of grassland NPP in response to climate change from 1982 to 2008. Results showed that the largest area of grassland distribution during the study period was in Asia (1737.23×104 km2), while the grassland area in Europe was relatively small (202.83×104 km2). Temporally, the total NPP increased with fluctuations from 1982 to 2008, with an annual increase rate of 0.03 Pg C/yr. The total NPP experienced a significant increasing trend from 1982 to 1995, while a decreasing trend was observed from 1996 to 2008. Spatially, the grassland NPP in South America and Africa were higher than the other regions, largely as a result of these regions are under warm and wet climatic conditions. The highest mean NPP was recorded for savannas (560.10 g C/(m2·yr)), whereas the lowest was observed in open shrublands with an average NPP of 162.53 g C/(m2·yr). The relationship between grassland NPP and annual mean temperature and annual precipitation (AMT, AP, respectively) varies with changes in AP, which indicates that, grassland NPP is more sensitive to precipitation than temperature.

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    Spatiotemporal Characteristics of Rural Labor Migration in China: Evidence from the Migration Stability under New-type Urbanization
    DENG Wei, ZHANG Shaoyao, ZHOU Peng, PENG Li, LIU Ying, WAN Jiangjun
    中国地理科学    2020, 30 (5): 749-764.   DOI: 10.1007/s11769-020-1147-7
    摘要182)      PDF (3495KB)(248)   
    Although the factors affecting rural-to-urban migration have been discussed and analyzed in detail, few studies have examined the spatiotemporal dynamic characteristics of rural migrants' employment and working-cities in the post-immigrate era, which is essential for the citizenization and social integration of new-type urbanization in China. This study uses survey data from rural migration laborers across the eastern, central, and western China to construct a comprehensive labor migration stability index, and compares the determinants of the migration stability of rural labor among cities and industries using Geodetector. The results are as follows:1) Compared with the midwestern cities, eastern cities have attracted younger and more skilled rural labor, and industries with higher technical content have higher migration stability among rural laborers. 2) Rural laborers more often adapt to changes by changing employment instead of changing working-cities. 3) The individual experiences of rural laborers and urban characteristics have significant impacts on the stability of migration, and family and societal guanxi (Chinese interpersonal relationships) enhance migration stability. 4) A unified labor market and convenient transportation have somewhat slowed industrial transfers and labor backflow. This study enhances our understanding of the roles of industrial transfer and new-type urbanization in shaping the labor geography landscape and provides policy implications for the promotion of people-oriented urbanization.
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    The 2012 Flash Drought Threatened US Midwest Agroecosystems
    JIN Cui, LUO Xue, XIAO Xiangming, DONG Jinwei, LI Xueming, YANG Jun, ZHAO Deyu
    中国地理科学    2019, 20 (5): 768-783.   DOI: 10.1007/s11769-019-1066-7
    摘要181)      PDF (35692KB)(405)   

    In the summer of 2012, the US Midwest, the most productive agricultural region in the world, experienced the most intense and widespread drought on record for the past hundred years. The 2012 drought, characterized as ‘flash drought’, developed in May with a rapid intensification afterwards, and peaked in mid-July.~76% of crop region and 60% of grassland and pasture regions have been under moderate to severe dry conditions. This study used multiple lines of evidences, i.e., in-situ AmeriFlux measurements, spatial satellite observations, and scaled ecosystem modeling, to provide independent and complementary analysis on the impact of 2012 flash drought on the US Midwest vegetation greenness and photosynthesis carbon uptake. Three datasets consistently showed that 1) phenological activities of all biomes advanced 1-2 weeks earlier in 2012 compared to the other years of 2010-2014; 2) the drought had a more severe impact on agroecosystems (crop and grassland) than on forests; 3) the growth of crop and grassland was suppressed from June with significant reduction of vegetation index, sun-induced fluorescence (SIF) and gross primary production (GPP), and did not recover until the end of growing season. The modeling results showed that regional total GPP in 2012 was the lowest (1.76 Pg C/yr) during 2010-2014, and decreased by 63 Tg C compared with the other-year mean. Agroecosystems, accounting for 84% of regional GPP assimilation, were the most impacted by 2012 drought with total GPP reduction of 9%, 7%, 6%, and 29% for maize, soybean, cropland, and grassland, respectively. The frequency and severity of droughts have been predicted to increase in future. The results imply the importance to investigate the influences of flash droughts on vegetation productivity and terrestrial carbon cycling.

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    Analysis of Metro Station Ridership Considering Spatial Heterogeneity
    GAN Zuoxian, FENG Tao, YANG Min, Harry TIMMERMANS, LUO Jinyu
    中国地理科学    2019, 29 (6): 1065-1077.   DOI: 10.1007/s11769-019-1065-8
    摘要177)      PDF (13258KB)(289)   

    This study aims to explore the role of spatial heterogeneity in ridership analysis and examine the relationship between built environment, station attributes and urban rapid transit ridership at the station level. Although spatial heterogeneity has been widely acknowledged in spatial data analysis, it has been rarely considered in travel behavior studies. Four models (three global models-ordinary least squares (OLS), spatial lag model (SLM), spatial error model (SEM) and one local model-geographically weighted regression (GWR) model) are estimated separately to explore the relationship between various independent variables and station ridership, and identify the influence of spatial heterogeneity. Using the data of built environment and station characteristics, the results of diagnostic identify evidence the existence of spatial heterogeneity in station ridership for the metro network in Nanjing, China. Results of comparing the various goodness-of-fit indicators show that, the GWR model yields the best fit of the data, performance followed by the SEM, SLM and OLS model. The results also demonstrate that population, number of lines, number of feeder buses, number of exits, road density and proportion residential area have a significant impact on station ridership. Moreover, the study pays special attention to the spatial variation in the coefficients of the independent variables and their statistical significance. It underlines the importance of taking spatial heterogeneity into account in the station ridership analysis and the decision-making in urban planning.

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    Post-industrial Economic Restructuring and Wage Inequality in Urban China, 2003-2015: A Sectoral Perspective
    YANG Fiona Fan, HU Fox Zhiyong, WANG Yuhua
    中国地理科学    2020, 30 (3): 516-531.   DOI: 10.1007/s11769-020-1125-0
    摘要175)      PDF (2047KB)(123)   
    Income inequality in urban China has attracted growing attention from China's urban researchers and policy makers. Whereas many studies have interrogated the pattern and process of the income gap in Chinese cities undergoing the institutional transformation from plan to market, relatively little is known about how such unequal distribution of income is related to China's ongoing structural transformation toward a post-industrial economy. Drawing on a decomposition methodology based on the Theil index, this study aimed to address this lacuna through an empirical investigation of China's urban wage inequality from a sectoral perspective. Our empirical study identified the low-wage manufacturing sector and the high-wage producer services sector as the two biggest contributors to urban wage inequality in China. Urban wage inequality within the producer services was found to be caused by the spatial concentration of a disproportionate number of high-paying jobs in a few developed, high-tier city-regions on the eastern coast. Our empirical findings have important implications for the formulation of policies to address the income inequality that plagues China's continuing urbanization.
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