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    Global Trends in Dam Removal and Related Research: A Systematic Review Based on Associated Datasets and Bibliometric Analysis
    DING Liuyong, CHEN Liqiang, DING Chengzhi, TAO Juan
    中国地理科学    2019, 20 (1): 1-12.   DOI: 10.1007/s11769-018-1009-8
    摘要207)      PDF (2915KB)(1201)   

    Dam removal has been increasingly reported globally and is becoming an important approach for river management, restoration and environmental conservation in damming rivers. However, current limited knowledge of global trends in dam removal and related research may be potentially biased in terms of the geographic distribution and organisms studied. Such bias could mislead dam removal planning and management in different areas and ecological conservation for different taxa. In this study, we quantitatively and qualitatively analyzed datasets of dam removal and publications of dam removal research using bibliometric methods. A total of 1449 dam removal documents were published from 1953 to 2016. Trends, current hotspots and future directions of dam removal research were identified. The results from this study reveal that dam removal largely occurred in the North America and Europe, and most of the removed dams were small and old dams. With respect to the topic analysis, more dam removal studies should focus on the responses of a wide range of organisms, not only fish, as well as the interspecies relationships, food webs and ecosystem structures and functions. Based on our findings, we also provide some suggestions for future dam removal planning and analysis.

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    Urban Expansion in China Based on Remote Sensing Technology: A Review
    ZHANG Zengxiang, LIU Fang, ZHAO Xiaoli, WANG Xiao, SHI Lifeng, XU Jinyong, YU Sisi, WEN Qingke, ZUO Lijun, YI Ling, HU Shunguang, LIU Bin
    中国地理科学    2018, 28 (5): 727-743.   DOI: 10.1007/s11769-018-0988-9
    摘要253)      PDF (2444KB)(1133)   

    Urban areas and its evolution are important anthropogenic indicators and human ecological footprints, and play decisive roles in environmental change analysis, global geo-conditional monitoring, and sustainable development. China has the highest rate of urban expansion and has emerged as an urban expansion hotspot worldwide. In this paper, the progress of studies on Chinese urban expansion based on remote sensing technology are summarized and analyzed from the aspects of urban area definition, remotely sensed imagery applied in urban expansion, monitoring methods of urban expansion, and urban expansion applications. Existing issues and future direc-tions of Chinese urban expansion are discussed and proposed. Results indicate that:1) The fusion of multi-source remotely sensed imagery is imperative to meet the needs of urban expansion with various monitoring terms and frequencies on different scales and dimensions. 2) To guarantee the classification accuracy and efficiency and describe urban expansion and its influences on local land use simultaneously, the combination of visual interpretation and automatic classification is the tendency of future monitoring methods of urban areas. 3) Urban expansion data have become the prerequisite for recognizing the urban development process, excavating its driving forces, simulating and predicting the future development directions, and also is conducive to revealing and explaining urban ecological and environmental issues. 4) In the past decades, Chinese scholars have promoted the application of remote sensing technology in the urban expansion field, with data construction, methods and models developing from the quotation stage to improvement and innovation stage; however, an independent and consistent urban expansion data on the national scale with long-term and high-frequency (such as annual monitoring) monitoring is still lacking.

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    Water Cooperation Priorities in the Lancang-Mekong River Basin Based on Cooperative Events Since the Mekong River Commission Establishment
    FENG Yan, WANG Wenling, SUMAN Daniel, YU Shiwei, HE Daming
    中国地理科学    2019, 20 (1): 58-69.   DOI: 10.1007/s11769-019-1016-4
    摘要146)      PDF (366KB)(984)   

    The Lancang-Mekong River has attracted much attention from researchers, but the cooperation on water issues in this river basin has been limited, even after the establishment of the Mekong River Commission (MRC). Cooperation on water resources has been determined as one of the key priority areas in the Lancang-Mekong Cooperation Mechanism, but there are no details of targets. In order to establish the priorities of water cooperation under the mechanism, we adopted nine categories to classify the objectives of 87 water cooperation events based on the ‘Lancang-Mekong Water Cooperative Events Database’ from 1995 to 2015. Based on the occurrence of cooperative events, cooperative objectives, cooperative scales, and approaches to cooperation, we conducted statistical, correlation, and text analyses. Our analyses indicated the following results:under the impact of economic conditions inside and outside the river basin, full cooperation appeared more difficult than bilateral and multilateral cooperation. Each of the partners adopted different preferences for cooperation targets. Cooperation with more definite objectives was easier to establish than cooperation with broader and more complex objectives. The potential objectives for water cooperation were navigation, hydropower, joint management, data sharing, flood control and water use. Because hydropower development is controversial, and because water cooperation is avoided by most existing regional cooperation mechanisms due to its complexity, we suggest the following priority areas for water cooperation in the Lancang-Mekong River Basin. 1) Navigation and flood control/drought relief are attractive objectives for all the riparian countries across the whole watershed. 2) Data sharing should be a priority for cooperation in the watershed due to its laying the foundation for the equitable and reasonable utilization of transboundary waters. 3) Hydropower is an objective best implemented mainly through bilateral cooperation, and on tributaries.

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    Transport Accessibility and Spatial Connections of Cities in the Guangdong-Hong Kong-Macao Greater Bay Area
    CAO Xiaoshu, OUYANG Shishu, YANG Wenyue, LUO Yi, LI Baochao, LIU Dan
    中国地理科学    2019, 20 (5): 820-833.   DOI: 10.1007/s11769-019-1034-2
    摘要162)      PDF (6142KB)(904)   

    Based on geographic information system (GIS) spatial analysis technology, the spatial pattern of raster grid transport accessibility for the Guangdong-Hong Kong-Macao Greater Bay area was studied and the states of spatial connectedness were simulated using highway passenger transport, railway passenger transport, port passenger transport and aviation passenger transport data. The result shows that transport accessibility within the Guangdong-Hong Kong-Macao Greater Bay area costs ‘one hour’ and the spatial distribution of accessibility in the area presents clear ‘core-periphery’ spatial characteristics, with Guangzhou, Foshan, Shenzhen constituting the core. The transport accessibility of Guangdong-Hong Kong-Macao is high. Average accessibility of urban nodes as measured by travel time is 0.99 h, and the areas accessible within 1.42 h occupy 79.14% of the total area. Most of the areas with the lowest accessibility are found in the peripheral area, with the worst accessibility being 4.73 h. Compared with the west-side cities, the economically developed east-side cities of the Guangdong-Hong Kong-Macao Greater Bay area have higher connectivity with roads, railways, ports, and aviation transport. Guangzhou, Foshan, Zhuhai, Shenzhen, Hong Kong and Macao are closely linked. The higher the accessibility, the closer the intercity connectedness.

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    Analysis of Social and Psychological Terrain of Bank Erosion Victims: A Study Along the Bhagirathi River, West Bengal, India
    Aznarul ISLAM, Sanat Kumar GUCHHAIT
    中国地理科学    2018, 28 (6): 1009-1026.   DOI: 10.1007/s11769-018-0937-7
    摘要205)      PDF (2006KB)(874)   

    Social psychology of people affected by hazards is different from normal psychology. For example, severe bank erosion in the lower reach of the Bhagirathi River in West Bengal has resulted in significant land loss (~60% of all households lost land over last 20 years) and affected the livelihoods of the people in the study villages along the river. Per capita income has almost halved from 1970-2012 due to land loss. This stark nature of land erosion and vulnerability of livelihood has had far-reaching repercussions on the fabric of society and the psychology of the people in this region. Results showed that erosion-affected villages have registered comparatively larger average family sizes (~4.1 as compared to ~3.9 in non-affected villages), lower literacy levels (< 50% compared to > 65% for the non-affected villages), and poor health. Reports of poor health as a result of land erosion include~60% of the respondents having reported physical ailments such as headache and abdominal discomfort, as well as 3%-5% reporting loss of emotional and psychological balance. Villages suffering from erosion showed higher positive loadings in average-coefficient of variation (CV) differential (25%-40%) depicting objectivity in their opinions for select variables of social processes. Principal component analysis (PCA) portrayed maximum eigenvalues in the first principal component for interpersonal processes (~98%) and a minimum for intergroup processes (~80%). Categorical principal component analysis (CATPCA) depicted a cluster between interpersonal and intergroup processes and another between intra-individual and group categories. The positive loadings in female-male differences in CV of perceptions portrayed relative consistency of males over the females concerning fear/phobia and physical stress while negative loadings exhibited higher consistency for females regarding psychological stress and shock. Lastly, the Tajfel matrix portrayed a distinction between hazard psychology characterized by maximum joint profit as found in Rukunpur, and normal psychology characterized by in-group favoritism as found in Matiari.

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    Payments for Watershed Services and Practices in China: Achievements and Challenges
    LU Yan, XU Jianhua, QIN Fen, WANG Jiayao
    中国地理科学    2018, 28 (5): 873-893.   DOI: 10.1007/s11769-018-0981-3
    摘要185)      PDF (3731KB)(830)   

    Implementation of payments for watershed services (PWS) has been regarded as a promising approach to coordinating the interests of upstream and downstream ecosystem services stakeholders. There is growing concern about whether PWS programs have achieved their original environmental goals of improving water quality and quantity, as well as the ancillary objective of increasing the welfare of local people. We start with an overview of PWS schemes and focus on their particularity and implementation mechanisms in China. We proceed to review 62 active PWS cases and examine their environmental performance in detail. The resulting findings show that PWS schemes have been able to reduce water pollution to some extent by establishing collaborative upstream/downstream watershed management policies, thereby improving water quality and quantity, as well as by making government officials more responsible for water resource management. In addition, their continued effectiveness in light of present challenges such as water-quality data availability is discussed. Chinese PWS schemes and their implementation mechanisms also provide information useful in monitoring environmental outcomes and guiding future designs of PWS programs in other regions.

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    Detecting Global Vegetation Changes Using Mann-Kendal (MK) Trend Test for 1982-2015 Time Period
    GUO Meng, LI Jing, HE Hongshi, XU Jiawei, JIN Yinghua
    中国地理科学    2018, 28 (6): 907-919.   DOI: 10.1007/s11769-018-1002-2
    摘要264)      PDF (9463KB)(817)   

    Vegetation is the main component of the terrestrial ecosystem and plays a key role in global climate change. Remotely sensed vegetation indices are widely used to detect vegetation trends at large scales. To understand the trends of vegetation cover, this research examined the spatial-temporal trends of global vegetation by employing the normalized difference vegetation index (NDVI) from the Advanced Very High Resolution Radiometer (AVHRR) Global Inventory Modeling and Mapping Studies (GIMMS) time series (1982-2015). Ten samples were selected to test the temporal trend of NDVI, and the results show that in arid and semi-arid regions, NDVI showed a deceasing trend, while it showed a growing trend in other regions. Mann-Kendal (MK) trend test results indicate that 83.37% of NDVI pixels exhibited positive trends and that only 16.63% showed negative trends (P < 0.05) during the period from 1982 to 2015. The increasing NDVI trends primarily occurred in tree-covered regions because of forest growth and re-growth and also because of vegetation succession after a forest disturbance. The increasing trend of the NDVI in cropland regions was primarily because of the increasing cropland area and the improvement in planting techniques. This research describes the spatial vegetation trends at a global scale over the past 30+ years, especially for different land cover types.

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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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    New Developments and Perspectives in Physical Geography in China
    FU Bojie, TIAN Tao, LIU Yanxu, ZHAO Wenwu
    中国地理科学    2019, 20 (3): 363-371.   DOI: 10.1007/s11769-019-1038-y
    摘要220)      PDF (300KB)(750)   

    Physical geography is the cornerstone of geography. In this article, the starting points of disciplines in physical geography in recent years in China are discussed. With the coupling of systems set as the research object, and sustainable development as the ultimate goal, the upgrade of physical geography can be deconstructed into three steps:deepen physical geography from the perspective of pattern-process coupling, improve the focus of physical geography from ecosystem processes to ecosystem services, and increase the understanding of the physical geography ‘pattern, process, service, sustainability’ research cascade. The incorporation of human activities into physical geographic processes is essential to conduct integrated analysis on physical and human factors at different scales. The development of ecosystem service models that couple supply-demand and sustainable development are of great importance to bridge the role of ecosystem services between the natural environment and human well-being. Moreover, human-land systems and sustainable development have become the core areas and frontiers of integrated physical geography and even geography in general. China faces the great strategic demand of constructing an ecological civilization in a new era, and the development of the disciplines of physical geography should give full access to the advantages of intersecting and comprehensive disciplines, focus on the human-land system patterns, processes, and services in key research areas, and provide disciplinary support for regional, national, and global sustainable development.

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    Estimation and Spatio-temporal Patterns of Carbon Emissions from Grassland Fires in Inner Mongolia, China
    YU Shan, JIANG Li, DU Wala, ZHAO Jianjun, ZHANG Hongyan, ZHANG Qiaofeng, LIU Huijuan
    中国地理科学    2020, 30 (4): 572-587.   DOI: 10.1007/s11769-020-1134-z
    摘要120)      PDF (6122KB)(707)   
    Grassland fires results in carbon emissions, which directly affects the carbon cycle of ecosystems and the carbon balance. The grassland area of Inner Mongolia accounts for 22% of the total grassland area in China, and many fires occur in the area every year. However, there are few models for estimation of carbon emissions from grassland fires. Accurate estimation of direct carbon emissions from grassland fires is critical to quantifying the contribution of grassland fires to the regional balance of atmospheric carbon. In this study, the regression equations for aboveground biomass (AGB) of grassland in growing season and MODIS NDVI (Normalized Difference Vegetation Index) were established through field experiments, then AGB during Nov.-Apr. were retrieved based on that in Oct. and decline rate, finally surface fuel load was obtained for whole year. Based on controlled combustion experiments of different grassland types in Inner Mongolia, the carbon emission rate of grassland fires for each grassland type were determined, then carbon emission was estimated using proposed method and carbon emission rate. Results revealed that annual average surface fuel load of grasslands in Inner Mongolia during 2000-2016 was approximately 1.1978×1012 kg. The total area of grassland which was burned in the Inner Mongolia region over the 17-year period was 5298.75 km2, with the annual average area of 311.69 km2. The spatial distribution of grassland surface fuel loads is characterized by decreasing from northeast to southwest in Inner Mongolia. The total carbon emissions from grassland fires amounted to 2.24×107 kg with an annual average of 1.32×106 for the study area. The areas with most carbon emissions were mainly concentrated in Old Barag Banner and New Barag Right Banner and on the right side of the Oroqin Autonomous Banner. The spatial characteristics of carbon emission depend on the location of grassland fire, mainly in the northeast of Inner Mongolia include Hulunbuir City, Hinggan League, Xilin Gol League and Ulanqab City. The area and spatial location of grassland fires can directly affect the total amount and spatial distribution of carbon emissions. This study provides a reference for estimating carbon emissions from steppe fires. The model and framework for estimation of carbon emissions from grassland fires established can provide a reference value for estimation of carbon emissions from grassland fires in other regions.
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    Three Types of Spatial Function Zoning in Key Ecological Function Areas Based on Ecological and Economic Coordinated Development: A Case Study of Tacheng Basin, China
    WANG Guiling, YANG Degang, XIA Fuqiang, ZHONG Ruisen, XIONG Chuanhe
    中国地理科学    2019, 20 (4): 689-699.   DOI: 10.1007/s11769-019-1022-6
    摘要184)      PDF (2003KB)(704)   

    Three types of spatial function zoning is an effective measure for regional environmental protection and orderly development. For ecological and economic coordinated development, spatial function zones should be divided scientifically to clear its direction of development and protection. Therefore, based on ecological constraints, a beneficial discussion would be about the key ecological function areas adopting the concept of ecological protection restriction and supporting socioeconomic development for spatial function zoning. In this paper, the researchers, taking Tacheng Basin, Xinjiang of China as an example, choose township as basic research unit and set up an evaluation index system from three aspects, namely, ecological protection suitability, agricultural production suitability, and urban development suitability, which are analyzed by using spatial analysis functions and exclusive matrix method. The results showed that:1) This paper formed a set of multilevel evaluation index systems for three types of spatial function zoning of the key ecological function areas based on a novel perspective by scientifically dividing Tacheng Basin into ecological space, agricultural space, and urban space, which realized the integration and scientific orientation for spatial function at the township scale. 2) Under the guidance of three types of spatial pattern, the functional orientation and suggestions of development and protection was clearly defined for ecological protection zones, ecological economic zones, agricultural production zones, and urban development zones. 3) A new idea of space governance is provided to promote the coordinated and sustainable development between ecology and economy, which can break the traditional mode of thinking about regional economic development, and offers a scientific basis and reference for macro decision-making.

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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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    Comparison of Carbon, Nitrogen, and Sulfur in Coastal Wetlands Dominated by Native and Invasive Plants in the Yancheng National Nature Reserve, China
    WAN Siang, LIU Xingtu, MOU Xiaojie, ZHAO Yongqiang
    中国地理科学    2020, 30 (2): 202-216.   DOI: 10.1007/s11769-020-1108-1
    摘要146)      PDF (1109KB)(657)   
    The rapid invasion of the plant Spartina alterniflora in coastal wetland areas can threaten the capacity of their soils to store carbon (C), nitrogen (N), and sulfur (S). In this study, we investigated the spatial and temporal distribution patterns of C, N and S of both soil and (native and invasive) plants in four typical coastal wetlands in the core area of the Yancheng National Nature Reserve, China. The results show that the invasive S. alterniflora greatly influenced soil properties and increased soil C, N and S storage capacity:the stock (mean ±standard error) of soil organic carbon (SOC, (3.56 ±0.36) kg/m3), total nitrogen (TN, (0.43 ±0.02) kg/m3), and total sulfur (TS, (0.69 ±0.11) kg/m3) in the S. alterniflora marsh exceeded those in the adjacent bare mudflat, Suaeda salsa marsh, and Phragmites australis marsh. Because of its greater biomass, plant C ((1193.7 ±133.6) g/m2), N ((18.8 ±2.4) g/m2), and S ((9.4 ±1.5) g/m2) storage of S. alterniflora was also larger than those of co-occurring native plants. More biogenic elements circulated in the soil-plant system of the S. alterniflora marsh, and their spatial and temporal distribution patterns were also changed by the S. alterniflora invasion. Soil properties changed by S. alterniflora's invasion thereby indirectly affected the accumulation of soil C, N and S in this wetland ecosystem. The SOC, TN, and TS contents were positively correlated with soil electrical conductivity and moisture, but negatively correlated with the pH and bulk density of soil. Together, these results indicate that S. alterniflora invasion altered ecosystem processes, resulted in changes in net primary production and litter decomposition, and increased the soil C, N and S storage capacity in the invaded ecosystems in comparison to those with native tallgrass communities in the coastal wetlands of East China.
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    Analyzing Population Density Disparity in China with GIS-automated Regionalization: The Hu Line Revisited
    WANG Fahui, LIU Cuiling, XU Yaping
    中国地理科学    2019, 20 (4): 541-552.   DOI: 10.1007/s11769-019-1054-y
    摘要330)      PDF (698KB)(640)   

    The famous ‘Hu Line’, proposed by Hu Huanyong in 1935, divided China into two regions (southeast and northwest) of comparable area size but drastically different in population. However, the classic Hu Line was derived manually in absence of reliable census data and computational technologies of modern days. It has been subject to criticism of lack of scientific rigor and accuracy. This research uses a GIS-automated regionalization method, termed REDCAP (Regionalization with Dynamically Constrained Agglomerative Clustering and Partitioning), to reconstruct the demarcation line based on the 2010 county-level census data in China. The results show that the logarithmic transformation of population density is a better measure of attributive homogeneity in derived regions than density itself, and produces two regions of nearly identical area size and greater contrast in population. Specifically, the revised Hu Line by Hu Huanyong in 1990 had the southeast region with 94.4% of total population and 42.9% of total land, and our delineation line yields a southeast region with 97.4% population and 50.8% land. Therefore, the population density ratio of the two regions is 27.1 by our line, much higher than the ratio of 22.4 by the Hu Line, and thus outperforms the Hu Line in deriving regions of maximum density contrast with comparable area size. Furthermore, more regions are delineated to further advance our understanding of population distribution disparity in China.

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    Hydrological Simulation Using TRMM and CHIRPS Precipitation Estimates in the Lower Lancang-Mekong River Basin
    LUO Xian, WU Wenqi, HE Daming, LI Yungang, JI Xuan
    中国地理科学    2019, 20 (1): 13-25.   DOI: 10.1007/s11769-019-1014-6
    摘要172)      PDF (3536KB)(634)   

    Satellite-based products with high spatial and temporal resolution provide useful precipitation information for data-sparse or ungauged large-scale watersheds. In the Lower Lancang-Mekong River Basin, rainfall stations are sparse and unevenly distributed, and the transboundary characteristic makes the collection of precipitation data more difficult, which has restricted hydrological processes simulation. In this study, daily precipitation data from four datasets (gauge observations, inverse distance weighted (IDW) data, Tropical Rainfall Measuring Mission (TRMM) estimates, and Climate Hazards Group InfraRed Precipitation with Stations (CHIRPS) estimates), were applied to drive the Soil and Water Assessment Tool (SWAT) model, and then their capability for hydrological simulation in the Lower Lancang-Mekong River Basin were examined. TRMM and CHIRPS data showed good performances on precipitation estimation in the Lower Lancang-Mekong River Basin, with the better performance for TRMM product. The Nash-Sutcliffe efficiency (NSE) values of gauge, IDW, TRMM, and CHIRPS simulations during the calibration period were 0.87, 0.86, 0.95, and 0.93 for monthly flow, respectively, and those for daily flow were 0.75, 0.77, 0.86, and 0.84, respectively. TRMM and CHIRPS data were superior to rain gauge and IDW data for driving the hydrological model, and TRMM data produced the best simulation performance. Satellite-based precipitation estimates could be suitable data sources when simulating hydrological processes for large data-poor or ungauged watersheds, especially in international river basins for which precipitation observations are difficult to collect. CHIRPS data provide long precipitation time series from 1981 to near present and thus could be used as an alternative precipitation input for hydrological simulation, especially for the period without TRMM data. For satellite-based precipitation products, the differences in the occurrence frequencies and amounts of precipitation with different intensities would affect simulation results of water balance components, which should be comprehensively considered in water resources estimation and planning.

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    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
    NAN Ying, WANG Bingbing, ZHANG Da, LIU Zhifeng, QI Dekang, ZHOU Haohao
    中国地理科学    2020, 30 (4): 588-599.   DOI: 10.1007/s11769-020-1136-x
    摘要134)      PDF (3033KB)(615)   
    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.
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    Impacts of Coastal Reclamation on Natural Wetlands in Large River Deltas in China
    MA Tiantian, LI Xiaowen, BAI Junhong, CUI Baoshan
    中国地理科学    2019, 20 (4): 640-651.   DOI: 10.1007/s11769-019-1049-8
    摘要206)      PDF (936KB)(611)   

    Little information is available on the impacts of coastal reclamation on wetland loss in large-river deltas at a regional scale. Using remote sensing data of coastal wetland and reclamation in four deltas in China from 1978 to 2014, we tracked their continuous area changes in four periods:1978-1990, 1990-2000, 2000-2008, and 2008-2014. The areal relation between wetland loss and reclamation was quantified and used to identify coastal reclamation mode intensity coupled with another three indicators:reclamation rate, accretion rate and land-use intensity of coastal reclamation. The results showed that coastal reclamation driven by economic development reduced, or even reverse the original growth of delta which was determined by the offset between wetland acceleration rate and wetland loss rate. Generally, the area of reclamation showed a positive linear correlation with the area of wetland loss. The findings imply that human activities should control reclamation rate and intensity to alleviate total wetland loss and maintain wetland ‘net gain’. Inappropriate coastal reclamation modes can magnify total wetland loss; therefore, coastal reclamation with a slow increment rate and low impervious surface percent is of great importance for sustainable development in future coastal management.

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    Comparative Study on Coastal Depth Inversion Based on Multi-source Remote Sensing Data
    LU Tianqi, CHEN Shengbo, TU Yuan, YU Yan, CAO Yijing, JIANG Deyang
    中国地理科学    2019, 20 (2): 192-201.   DOI: 10.1007/s11769-018-1013-z
    摘要308)      PDF (3182KB)(603)   

    Coastal depth is an important research focus of coastal waters and is also a key factor in coastal environment. Dongluo Island in South China Sea was taken as a typical study area. The band ratio model was established by using measured points and three multispectral images of Landsat-8, SPOT-6 (Systeme Probatoire d'Observation de la Terre, No.6) and WorldView-2. The band ratio model with the highest accuracy is selected for the depth inversion respectively. The results show that the accuracy of SPOT-6 image is the highest in the inversion of coastal depth. Meanwhile, analyzing the error of inversion from different depth ranges, the accuracy of the inversion is lower in the range of 0-5 m because of the influence of human activities. The inversion accuracy of 5-10 m is the highest, and the inversion error increases with the increase of water depth in the range of 5-20 m for the three kinds of satellite images. There is no linear relationship between the accuracy of remote sensing water depth inversion and spatial resolution of remote sensing data, and it is affected by performance and parameters of sensor. It is necessary to strengthen the research of remote sensor in order to further improve the accuracy of inversion.

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    Regional Characteristics and Causes of Haze Events in Northeast China
    CHEN Weiwei, ZHANG Shichun, TONG Quansong, ZHANG Xuelei, ZHAO Hongmei, MA Siqi, XIU Aijun, HE Yuexin
    中国地理科学    2018, 28 (5): 836-850.   DOI: 10.1007/s11769-018-0965-3
    摘要127)      PDF (3787KB)(602)   

    Northeast China experiences severe atmospheric pollution, with an increasing occurrence of heavy haze episodes. However, the underlying forces driving haze formation during different seasons are poorly understood. In this study, we explored the spatio-temporal characteristics and causes of haze events in Northeast China by combining a range of data sources (i.e., ground monitoring, satellite-based products, and meteorological products). It was found that the ‘Shenyang-Changchun-Harbin (SCH)’ city belt was the most polluted area in the region on an annual scale. The spatial distribution of air quality index (AQI) values had a clear seasonality, with the worst pollution occurring in winter, an approximately oval-shaped polluted area around western Jilin Province in spring, and the best air quality occurring in summer and most of the autumn. The three periods that typically experienced intense haze events were Period I from mid-October to mid-November (i.e., late autumn and early winter), Period Ⅱ from late-December to February (i.e., the coldest time in winter), and Period Ⅲ from April to mid-May (i.e., spring). During Period I, strong PM2.5 emissions from seasonal crop residue burning and coal burning for winter heating were the dominant reasons for the occurrence of extreme haze events (AQI > 300). Period Ⅱ had frequent heavy haze events (200 < AQI < 300) in the coldest months of January and February, which were due to high PM2.5 emissions from coal burning and vehicle fuel consumption, a lower atmospheric boundary layer, and stagnant atmospheric conditions. Haze events in Period Ⅲ, with high PM10 concentrations, were primarily caused by the regional transportation of windblown dust from degraded grassland in central Inner Mongolia and bare soil in western Jilin Province. Local agricultural tilling could also release PM10 and enhance the levels of windblown dust from tilled soil. Better control of coal burning, fuel consumption, and crop residue burning in winter and autumn is urgently needed to address the haze problem in Northeast China.

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    Impacts of Land Cover Changes on Ecosystem Carbon Stocks Over the Transboundary Tumen River Basin in Northeast Asia
    XIANG Hengxing, JIA Mingming, WANG Zongming, LI Lin, MAO Dehua, ZHANG Da, CUI Guishan, ZHU Weihong
    中国地理科学    2018, 28 (6): 973-985.   DOI: 10.1007/s11769-018-1006-y
    摘要133)      PDF (2449KB)(598)   

    Understanding the effects of land cover changes on ecosystem carbon stocks is essential for ecosystem management and environmental protection, particularly in the transboundary region that has undergone marked changes. This study aimed to examine the impacts of land cover changes on ecosystem carbon stocks in the transboundary Tumen River Basin (TTRB). We extracted the spatial information from Landsat Thematic Imager (TM) and Operational Land Imager (OLI) images for the years 1990 and 2015 and obtained convincing estimates of terrestrial biomass and soil carbon stocks with the InVEST model. The results showed that forestland, cropland and built-up land increased by 57.5, 429.7 and 128.9 km2, respectively, while grassland, wetland and barren land declined by 24.9, 548.0 and 43.0 km2, respectively in the TTRB from 1990 to 2015. The total carbon stocks encompassing aboveground, belowground, soil and litter layer carbon storage pools have declined from 831.48 Tg C in 1990 to 831.42 Tg C in 2015 due to land cover changes. In detail, the carbon stocks decreased by 3.13 Tg C and 0.44 Tg C in Democratic People's Republic of Korea (North Korea) and Russia, respectively, while increased by 3.51 Tg C in China. Furthermore, economic development, and national policy accounted for most land cover changes in the TTRB. Our results imply that effective wetland and forestland protection policies among China, North Korea, and Russia are much needed for protecting the natural resources, promoting local ecosystem services and regional sustainable development in the transnational area.

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