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    20 April 2018, Volume 37 Issue 4 Previous Issue    Next Issue
    Special Column: Young Geographer Forum
    Innovation and integration of geographic research promoted by the Young Scientist Fund of the National Natural Science Foundation of China
    Wenjie FAN, Xizhang GAO, Shuying LENG
    2018, 37 (4):  451-464.  doi: 10.18306/dlkxjz.2018.04.001
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    This study focused on the Young Scientist Fund in geography supported by the National Natural Science Foundation of China (NSFC) from 1987 to 2016. Using bibliometrics analysis method, keywords frequency was analyzed and compared with the NSFC general projects in the same period by the four sub-disciplines of geography—physical geography, human geography, geographic information science, and environmental geography. Change of research characteristics and selected topics were also tracked. Seven representative keywords were chosen to study the change of topics in these cutting-edge research areas. The growth of young scholars was analyzed through their follow-up funding from the NSFC. This study shows that from 1987, the Young Scientist Fund project topics have been at the frontier of the study on the patterns and processes of the land surface environment and human economic system. Technological innovation was the main driving force of the Young Scientist Fund projects in geography. The research continued to be quantitative and innovative and the topics were gradually expanded to be integrative. The Young Scientist Fund has significantly promoted technological and theoretical innovations of geography in China.

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    Advances and prospects of research on simulating transboundary black carbon and their climatic effects over the Tibetan Plateau
    Zhenming JI
    2018, 37 (4):  465-475.  doi: 10.18306/dlkxjz.2018.04.002
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    The Tibetan Plateau is surrounded by regions of the fastest growing atmospheric pollutants. The westerlies and the South Asian monsoon circulation transport the pollutants from Central Asia and South Asia to the inland of the Tibetan Plateau, which have important effects on the regional climate and environment. The concentration of black carbon in the snow and ice showed a clearly increasing trend during the recent few decades in the eastern and southern Tibetan Plateau, which might be associated with accelerated melting of snow and glaciers, and directly affected the hydrological processes on the plateau. However, the amount of transboundary transport of black carbon from South Asia is not clear and the knowledge of its impact on climate and cryosphere over the Tibetan Plateau is still limited. The development of atmospheric pollutants monitoring network on the Tibetan Plateau and the application of the high-resolution regional climate-atmospheric chemistry coupled model provide an opportunity for quantitative assessment of external transported pollutants and their climatic effects on the plateau. The project of “Simulation of transboundary transport of black carbon from South Asia and its impact on climate over the Tibetan Plateau,” which was supported by the National Natural Science Foundation of China, focused on the following three aspects: (1) Systematic assessment of the high-resolution regional climate-atmospheric chemistry coupled model performance in the simulation for the Tibetan Plateau. Based on the simulation of distribution, transportation, and deposition processes of black carbon over the Tibetan Plateau and surrounding regions, the climatic effects were investigated; (2) Examination of the mechanism of pollutant diffusion , and evaluation and comparison of the climatic effects induced by the anthropogenic and natural sources; (3) Quantitative estimation of the contribution of external pollutants outside the Tibetan Plateau. The results show that the black carbon from South Asia provided the highest contribution, which was 61.3% in the non-monsoon period and 19.4% in the monsoon season. This study revealed the effect of transboundary black carbon on the Tibetan Plateau, which may provide a scientific basis for improved management and prediction of the cryosphere and water resources in the core region of the Belt and Road initiative, and for police-making of climate change adaption and diplomatic negotiations.

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    Advances in research of hillslope soil hydrological processes in the humid region of Southeast China
    Kaihua LIAO, Ligang LV
    2018, 37 (4):  476-484.  doi: 10.18306/dlkxjz.2018.04.003
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    The humid region of Southeast China is one of the most prominent areas of environmental problems. Eutrophication of water bodies is a major problem that hampers the economic and social developments in the region. Especially in recent years, affected by government policies and market forces, the development of hilly and mountainous areas was intensified. Increasingly more virgin bamboo forests have been developed into economic land (such as tea garden). However, the land-use and land-cover change brings economic benefits as well as changes of soil pore structure and hydrological processes, which greatly affect the migration and transformation of nutrients in the soil. Within the National Natural Science Foundation of China (NSFC) supported project “Research on the physical mechanism and numerical simulation of hillslope soil hydrological processes in the hilly region of the Taihu Lake Basin” we made important progresses in the following three aspects: (1) spatiotemporal variations and influencing factors of hillslope soil moisture under different land use; (2) hillslope hydrological processes and water balance; and (3) influencing mechanism of hillslope soil hydrological processes. Despite these progresses, further research should focus on mechanisms of such processes, which would be of great importance for the control of eutrophication of the Taihu lake and non-point source pollution.

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    Articles
    Characteristics of temperature changes during the past millennium along the Ancient Silk Road
    Zhixin HAO, Yani LIANG, Yang LIU, Xiu GENG, Jingyun ZHENG
    2018, 37 (4):  485-494.  doi: 10.18306/dlkxjz.2018.04.004
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    Based on the recently published multi-proxies temperature reconstruction series (longer than 1000 years) along the Ancient Silk Road, combined with the dry and wet condition variation reconstructions, the general characteristics of temperature changes were analyzed and the regional differences of dry and wet condition variations were compared for the Medieval Climate Anomaly (MCA, AD950-AD1250) and Little Ice Age (LIA, AD1450-AD1850). The main conclusions are: the centennial temperature variations during the past 2000 years experienced warm epochs in the 1st-3rd century, the latter part of the 7th century to the early of the 11th century, the mid-12th century to mid-13th century, and since the 20th century; and cold epochs during the 4th century to the early 7th century, the middle of the 11th century to the early 12th century, and the end of the 13th century to the mid-19th century. The phases of warm and cold condition and fluctuations at decadal-centennial temporal scales differed among the various regions. The wet and dry condition variations during the MCA and LIA also exhibited regional differences, which was larger during the MCA than the LIA on the Guanzhong Plain and in the Hexi Corridor of China, and the climate was dry during the MCA and wet during the LIA in the arid region of Central Asia. The climate was drier during the MCA than the LIA in the south of Scandinavia and the middle and northern parts of Europe, and in the central part of this region the variation was large during the LIA. In contrast, Finland, northern Scandinavia, and Russia had wetter climate during the MCA.

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    Spatiotemporal distribution of high flood risk areas in China, 1736-1911
    Lingbo XIAO
    2018, 37 (4):  495-503.  doi: 10.18306/dlkxjz.2018.04.005
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    The reconstruction of spatiotemporal distribution of extreme climatic disasters in the past is important for the identification of high risk zones at present, the prediction of change in the future, and improved response to the challenges of climate change. In this study, information about historical floods was extracted from the Qing History, and counties suffered from floods during 1736-1911 were identified year by year, which sum to 8,582. Using the kernel density estimation method, spatial distribution of hotspots where floods occurred frequently during 1736-1911 was reconstructed, and the spatial differences among three periods (1736-1795, 1796-1850, and 1851-1911) were analyzed with the theoretical framework of disaster risk developed by the Intergovernmental Panel on Climate Change (IPCC). It is found that the main high risk areas during 1736-1911were the lower reaches of the Yellow River and the Hai River on the North China Plain, the lower reach of the Huai River, and the three great plains (Jianghan-Dongting Lake, Poyang Lake, and Tai Lake) in the middle-lower Yangtze River Basin and riparian areas, and the spatial pattern of floods was slightly different from the modern time. The lower Yellow River and Hai River were the most significant hotspots where floods were concentrated. It was partly because in the 18th and the 19th centuries the annual precipitation in the North China Plain was more than the 20th century, and the high vulnerability of regional socioeconomic system throughout the 19th century also played a negative role in damage control. After the Yellow River changed its course in 1855, new levees were not built until the 1870s because of social unrest and financial crisis, which led to a new high risk area with a banding distribution along the course of the Yellow River in northeast Shandong Province. In the 19th century, flood occurred much more frequently in the middle-lower Yangtze River Basin than the 18th century. On the one hand, due to the change of Meiyu, extreme precipitation events significantly increased in the area; on the other hand, inappropriate agricultural development (such as diked field) led to rapid disappearance of natural wetlands and lakes, which meant higher water level in flood period and more exposure to flood.

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    Spatiotemporal variability of heat waves and influencing factors in the Qinling-Huaihe region, 1960-2016
    Shuangshuang LI, Junping YAN, Saini YANG, Shushan HU, Yi ZHAO
    2018, 37 (4):  504-514.  doi: 10.18306/dlkxjz.2018.04.006
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    In the context of global warming, the likelihood of concurrent heat waves is expected to increase in most parts of China, which will have social and environmental impacts. However, heat wave characteristics are likely to vary regionally. Based on maximum daily temperature and relative humidity data from 134 meteorological stations for the 1960-2016 period, the spatiotemporal variation in heat waves was investigated for the Qinling-Huaihe region. We also analyzed the relationship between El Ni?o-Southern Oscillation (ENSO) and heat waves. We found that the heat waves in the past 57 years in the study region can be characterized as non-smooth and non-linear. Three distinct phases of decadal change were identified. During the first phase (1960-1972), with 112°E as the dividing line, heat waves were highly variable with alternating highs and lows in the western part of the region, but occurred at high frequency in the eastern part. During the second phase (1973-1993), heat waves showed low-amplitude fluctuations across the entire region, and rapidly increased in the mid-1980s. The third phase (1994-2016) saw high-amplitude fluctuations in heat waves in the western part of the region, but heat waves decreased in the eastern part. Our results show that over the entire region, the extremes in heat have been more sensitive to daily maximum temperature than regional relative humidity changes. Thus, the cooling of daily maximum temperature along the Huai River led to a decreasing heat wave spatial extent. There was also a notable difference in the relationship between ENSO and heat waves in the Qinling-Huaihe region: a strong positive correlation in the north and a weak negative correlation in the south were observed. Particularly, heat waves on the Guanzhong Plain have been closely related to Ni?o 4, whereas the relationship has been weak along the lower reach of the Yangtze River. The Ni?o 1+2 and Ni?o 3 indices showed significant negative correlations with heat waves across the lower reach of the Yangtze River. In the lower reach of the Yellow River and Qinling-Daba Mountains, the variations in heat waves have been weakly correlated with equatorial Pacific sea surface temperature anomalies. In addition, there has been more close relationship between temperature anomalies of equatorial Western Pacific and decadal variation of heat waves on the Guanzhong Plain in recent decades, which has contributed to enhanced warming on the Guanzhong Plain and along the lower reach of the Yangtze River.

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    Effect of anthropogenic heat release on temperature in different types of built-up land in Guangzhou, China
    Zheng CAO, Zhifeng WU, Wenjun MA
    2018, 37 (4):  515-524.  doi: 10.18306/dlkxjz.2018.04.007
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    Along with the rapid urbanization process, large amounts of anthropogenic heat are released into the atmosphere, which are becoming a key issue for regional weather condition. To understand what role anthropogenic heat release plays in regional temperature warming, Weather Research & Forecasting (WRF) model was applied to simulate temperature during 2-6 July 2010 with different configuration of anthropogenic heat release. The results indicate that the simulated temperature is consistent with the meteorological station observation data, with the correlation coefficient of 0.89 and the root-mean-square error of 2.96. High density residential area had the highest daily average temperature followed by industrial or commercial zone and low density residential area. On the other hand, low density residential area had the highest daily diurnal temperature range followed by high density residential area and industrial or commercial zone. Anthropogenic heat release caused a notable warming in the whole downtown area of Guangzhou City, which was more significant in high density residential area and commercial zone than low density residential area. The spatial association between temperature rise caused by anthropogenic heat release and building density is 0.17 (high density residential area), 0.14 (low density residential area), and 0.16 (industrial or commercial zone), respectively. Conversely, anthropogenic heat release decreased diurnal temperature range (the difference between daily maximum temperature and daily minimum temperature), which was more significant in high density residential area and commercial zone than low density residential area. The spatial association between daily temperature range decrease caused by anthropogenic heat release and building density is 0.14 (high density residential area), 0.15 (low density residential area), and 0.19 (industrial or commercial zone). Furthermore, when doubling the anthropogenic heat release, the spatial association between building density and simulated temperature rise and daily temperature range decrease was enhanced.

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    Impact of block size on residents’ travel appraisal in Beijing
    Li CHEN, Wenzhong ZHANG, Qiao CHU, Peng WANG, Jiazhong LI
    2018, 37 (4):  525-534.  doi: 10.18306/dlkxjz.2018.04.008
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    Residents' travel convenience and safety are significant concerns for a city's livability and sustainability. Existing transportation research has revealed a strong relationship between urban form characteristics and travel behavior. The rapid urban expansion of many Chinese cities in the past two decades has brought dramatic changes to their urban form and urban fabric. Wide multilane roads, super-long mega street blocks, and increasingly segregated land use are becoming important characteristics of Chinese cities once dominated by narrow allies/streets, tight urban fabric, and mixed-use work compounds, leading to increasing car travel and traffic congestion. Thus, there is a growing interest of scholars in China from geography and planning fields on the impact of urban built environment on travel behavior, especially when block size has become a key focus of urban spatial policymaking. However, little research has investigated urban residents' subjective assessment of their travel environments in China. Using the city of Beijing as a case study, this study took advantage of the latest built environment data and combined them with large scale geo-referenced satisfaction survey data to examine the impact of block size on residents’ travel convenience appraisal and travel safety appraisal. Ordered logit models were used to estimate the effect while controlling for socioeconomic factors. Several findings were generated: (1) Block size varies widely across Beijing. Generally speaking, it increases from the old traditional urban center to peripheral newly-built neighborhoods. But even in the central area, there are also some large blocks that consist of gated universities, hospitals, and other work compounds. The average block size of Beijing is much larger than other international cities. (2) Model results suggest that built environment with small block size could increase the number of road crossings and facilitate public transportation station siting, hence promote residents' travel convenience appraisal. Meanwhile, it could also decrease the travel risk caused by broad main roads, thus increase residents’ travel safety appraisal. (3) Other built environment indicators such as floor area ratio, location, and quantity of public transport stations also significantly influence residents' travel convenience and safety appraisal. (4) Some socioeconomic attributes have significant effects on travel appraisal as well, which indicates that the needs and spatial distribution of different kinds of residents should be taken into account while implementing transport-related policies. The results from the analysis suggest significant impacts that urban block size can exert on residents' travel convenience and safety, indicating the important role that spatial planning can play to help achieve the "green travel" goal promoted in urban China. Evidence generated from this study provides some theoretical support for the national policy of promoting small blocks.

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    Spatial optimization of mega-city fire station distribution based on Point of Interest data: A case study within the 5th Ring Road in Beijing
    Zhibang XU, Liang ZHOU, Ting LAN, Zhonghui WANG, Li SUN, Rongwei WU
    2018, 37 (4):  535-546.  doi: 10.18306/dlkxjz.2018.04.009
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    Sound spatial distribution of fire stations is important for urban development and for ensuring urban safety. Based on kernel density analysis and the SAVEE model, and taking into account different types of point of interest (POI) such as flammable and explosive and crowd fragility fire risk factors, 443410 POIs and road network were used to identify the fire risk zones in the downtown area of Beijing. Using the location-allocation fire station spatial optimization model, this study proposed adjustment plans. The main conclusions are as follows: (1) According to the fire risk ranking result, the top 10% fire risk areas are mainly concentrated in the CBD area Sanlitun, Beijing Antique Market Shuangjing, Wangfujing, and Nanluoguxiang-Yonghegong, among others. (2) The coverage rate (within 5 minute response) of the existing fire stations reached 96.46% for all 443,410 POIs, and the overall coverage was good, while some fire risk factors were covered with insufficient response in the northwestern and southwestern parts of the study area (Century City-Minzhuang area), and some fire station coverage area was too large. (3) Considering high fire risk areas, important fire risk factors, POI overall coverage rate, and individual fire station coverage area standards, the analysis by multiple iterations results in the final need of adding 15 new fire stations. With these additions, every performance indicator can be significantly improved and the demand of fire protection in the study area can be fully met.

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    Implications of commuting pattern for suburban residents’ health in large Chinese cities: Evidences from Tiantongyuan in Beijing
    Tingting FU, Yan ZHANG, Yanwei CHAI
    2018, 37 (4):  547-555.  doi: 10.18306/dlkxjz.2018.04.010
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    Suburbanization of Chinese cities has exacerbated home-work separation and led to the increase of long-distance commuting of suburbanites, which may affect their health status. In this article, taking Tiantongyuan in the inner suburb of Beijing as a case study, we focused on the impacts of suburban residents' commuting pattern on the health outcomes. In general, the overall commuting space of the full-time workers living in Tiantongyuan showed an uneven radial pattern centered at the community's location. According to commuting distance, commuting time, and commuting modes, the commuting patterns of the full-time employees living in Tiantongyuan can be clustered into three main types, including short distance-active commuting-public transit commuting, medium to long distance-public transit-car driving commuting, and long distance-public transit-car driving commuting. Controlling for other socioeconomic variables, this study used binary logistic regression models to verify the effect of commuting patterns on both physical and mental health outcomes. It was found that the effect of commuting patterns on poor sleep quality, frequent sick leaves, fatigue, stress, and other health risks showed an inverted U-shaped trend. Moderate commuting may be good for health, while extremely long commuting might be harmful to health. Especially, long distance-public transit-car driving commuting significantly increased the health risks of poor sleep quality, frequent sick leaves, and stress. Improving the home-work connection of the suburb is not only helpful for improving the efficiency of urban operation, but more importantly, is also meaningful for the improvement of the life quality of suburban residents.

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    Changing spatial pattern and accessibility of primary and secondary schools in a poor mountainous county: A case study of Song County, Henan Province
    Huimin YANG, Xiangling ZHANG, Li LI, Xiaojian LI, Bing WANG
    2018, 37 (4):  556-566.  doi: 10.18306/dlkxjz.2018.04.011
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    Poor mountainous regions in China suffer from economic underdevelopment, inconvenient transportation, scattered population distribution, and fast-changing residential spatial pattern. These make the study of spatial distribution changes of primary and secondary schools in these regions critical for improving education equality. By using the case of Song County in the poor mountainous region of western Henan Province, this study acquired long-term school data (1997, 2007, and 2015), and analyzed the changes in spatial pattern and spatial accessibility of these schools employing the trend surface analysis technique and gravity model. The results show that: (1) Primary and secondary schools in Song County were partially concentrated in areas with some terrain conditions. Primary schools were found more in the hilly and low-mountainous areas, and secondary schools concentrated in the hilly areas. (2) School merges decreased the total number of institutions and the differences in the number of schools among different villages, and the trend line became flat gradually. (3) The Cv value of the Voronoi model shows that schools followed an aggregated distribution pattern, and the degree of aggregation decreased as the number of schools decreased. The schools were mainly found in a region spreading from northeast to southwest in the northern part of the county, forming two narrow distribution bands along the two main roads (S247 and G311). (4) School accessibilities were spatially varied in 2015. The longest distance to school was 160 times that of the shortest distance to school. Villages that had more than 10 km distance to schools were all found in the mid-mountainous and low-mountainous areas, constituting 26.1% of the total number. (5) Terrain, transportation, population, economy, and government policy were all influential to the distribution of educational resources in Song County.

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    Review
    Analytical framework of sustainable poverty-reduction effect and mechanisms of anti-poverty models
    Yanhua LIU, Yong XU
    2018, 37 (4):  567-578.  doi: 10.18306/dlkxjz.2018.04.012
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    The "targeted poverty alleviation policy" is one of the most important strategies in recent years for China to build a well-off society in an all-round way. Among the many contents of this strategy, accurately identifying poor people and groups, arranging anti-poverty projects, and monitoring the effects of poverty reduction are the three core aspects. To ensure effective implementation of these policy objectives, a series of scientific and systematic methods for estimating and assessing the accuracy and efficiency of poverty reduction are necessary. However, related studies so far have focused mostly on the economic dimension, and very few of them have explored the underlying mechanisms or assessed the sustainability of poverty-reduction effects. From a multidimensional, dynamic, and systematic perspective, this article categorizes the anti-poverty models in rural China according to the main aspects each project works with, formulates a framework for analyzing the sustainable poverty-reduction effects of these models based on the sustainable livelihoods framework proposed by DFID, and then explores the working mechanism of each anti-poverty model. The result shows that the proposed framework can not only express whether the mechanism of an anti-poverty model matches the characteristics of the target poor people, but also assess the improvements it brings in multiple dimensions of people’s livelihoods and its sustainability. Thus the framework may help shine light on the development of systematic, comprehensive, and quantitative methods or models for estimating the sustainable poverty-reduction effects of anti-poverty projects.

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