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    Progress in watershed geography in the Yangtze River Basin and the affiliated ecological security perspective in the past 20 years, China
    GAO Yang, JIA Junjie, LU Yao, SUN Xiaomin, WEN Xuefa, HE Nianpeng, YANG Tiantian
    Journal of Geographical Sciences    2020, 30 (6): 867-880.   doi: 10.1007/s11442-020-1759-y
    Abstract245)   HTML19)    PDF (1720KB)(36)      

    Bibliometrics was used to statistically analyze key zones within the Yangtze River Basin (YRB) funded by the National Natural Science Foundation of China (NSFC) and national ministries over the past 20 years. This study determined that funds that derived from national ministries have mainly focused on issues related to environmental pollution, ecological security, technological water regulations, and river basin ecosystems, which offer a better understanding of the national requirements and the scientific knowledge of the YRB in combination with data from the NSFC. Under a background of bolstering the construction of green ecological corridors in the economic belt of the YRB, this study proposes future conceptual watershed research initiatives in this region as a study objective by reinforcing the implementation of the Chinese Ecosystem Research Network (CERN) and by emphasizing the use of new technologies, new methods, and new concepts for the prospective design of frontier research under the perspective of geoscience and earth system science. This study promotes large-scale scientific field and research objectives based on big science and big data.

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    Theoretical basis and technical methods of cyberspace geography
    GAO Chundong, GUO Qiquan, JIANG Dong, WANG Zhenbo, FANG Chuanglin, HAO Mengmeng
    Journal of Geographical Sciences    2019, 29 (12): 1949-1964.   doi: 10.1007/s11442-019-1698-7
    Abstract238)   HTML39)    PDF (5475KB)(228)      

    Cyberspace is a new spatial realm of activities involving both humans and data, and it has become a cornerstone of the national security of every country. A scientific understanding of cyberspace is essential for analyzing cyberspace incidents, governing cyberspace and ensuring cybersecurity. Accordingly, cyberspace has become a new field of geographic research in the Information Age. Against the backdrop of fierce international competition over cyberspace, there has been an urgent need to strengthen research between the fields of geography and cybersecurity, leading to theoretical and methodological innovations that have created the sub-discipline of cyberspace geography. Cyberspace geography (CG) extends geographical research from real spaces to virtual spaces, and its theoretical basis is the evolution of the traditional geographic human-land relationship theory into a human-land-network relationship theory. CG research includes constructing mapping relationships between cyberspace and real space, redefining the traditional geographic concepts of distance and regions for cyberspace, creating a language, models and methodologies for visually representing cyberspace, drawing maps of cyberspace, and researching the principles governing the evolution of cyberspace structures and behaviors. The technical methods of CG include collecting and integrating data on elements of cyberspace, visually representing cyberspace and conducting cyberspace situational and behavioral intelligence awareness. Intelligence awareness covers cyberspace situational status assessments, network hotspot event dissemination and traceability analysis, and network event situational simulations and risk predictions. CG offers new perspectives on the scientific understanding of cyberspace, the development of disciplines such as geography and cybersecurity, and the creation of national cybersecurity prevention and control mechanisms as well as a community of common future in cyberspace.

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    Exploring global food security pattern from the perspective of spatio-temporal evolution
    CAI Jianming, MA Enpu, LIN Jing, LIAO Liuwen, HAN Yan
    Journal of Geographical Sciences    2020, 30 (2): 179-196.   doi: 10.1007/s11442-020-1722-y
    Abstract193)   HTML17)    PDF (940KB)(81)      

    Food security is the primary prerequisite for achieving other Millennium Development Goals (MDGs). Given that the MDG of “halving the proportion of hungers by 2015” was not realized as scheduled, it will be more pressing and challenging to reach the goal of zero hunger by 2030. So there is high urgency to find the pattern and mechanism of global food security from the perspective of spatio-temporal evolution. In this paper, based on the analysis of database by using a multi-index evaluation method and radar map area model, the global food security level for 172 countries from 2000 to 2014 were assessed; and then spatial autocorrelation analysis was conducted to depict the spatial patterns and changing characteristics of global food security; then, multi-nonlinear regression methods were employed to identify the factors affecting the food security patterns. The results show: 1) The global food security pattern can be summarized as “high-high aggregation, low-low aggregation”. The most secure countries are mainly distributed in Western Europe, North America, Oceania and parts of East Asia. The least secure countries are mainly distributed in sub-Saharan Africa, South Asia and West Asia, and parts of Southeast Asia. 2) Europe and sub-Saharan Africa are hot and cold spots of the global food security pattern respectively, while in non-aggregation areas, Haiti, North Korea, Tajikistan and Afghanistan have long-historical food insecurity problems. 3) The pattern of global food security is generally stable, but the internal fluctuations in the extremely insecure groups were significant. The countries with the highest food insecurity are also the countries with the most fluctuated levels of food security. 4) The annual average temperature, per capita GDP, proportion of people accessible to clean water, political stability and non-violence levels are the main factors influencing the global food security pattern. Research shows that the status of global food security has improved since the year 2000, yet there are still many challenges such as unstable global food security and acute regional food security issues. It will be difficult to understand these differences from a single factor, especially the annual average temperature and annual precipitation. The abnormal performance of the above factors indicates that appropriate natural conditions alone do not absolutely guarantee food security,while the levels of agricultural development, the purchasing power of residents, regional accessibility, as well as political and economic stability have more direct influence.

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    Spatial production and spatial dialectic: Evidence from the New Urban Districts in China
    ZHUANG Liang, YE Chao, HU Senlin
    Journal of Geographical Sciences    2019, 29 (12): 1981-1998.   doi: 10.1007/s11442-019-1700-4
    Abstract190)   HTML14)    PDF (3866KB)(210)      

    New Urban Districts (NUDs) are the important spatial carriers to promote urban expansion or transformation. Since the 1990s, they have been playing a more and more crucial role in China’s urbanization. For NUDs in the strict sense we found that: 96% to the east of Hu Line; 56% within the municipal districts; 64% within 36 km from their every city center and below the area of 423 km 2. The regional distribution follows significant spatial difference as “Eastern Region (50%) - Central Region (42%) - Western Region (8%)”, and the provinces with the largest number of NUDs are Guangdong, Henan, Zhejiang, Liaoning, and Jiangsu. Furthermore, their interesting constructed process highlights the typical characteristics of spatial production and spatial dialectic. This paper uses the theory of the production of space, and discovers that the growth of NUDs is a rapid ternary dialectical process of spatial production: “representations of space” is guided by the top-down governmental power; “spatial practice” is reflected in the hierarchical and regional difference of spatial elements, such as the type, pattern, distance and area of NUD; “spaces of representation” embodies the tension between governmental power and urban development rights, as well as the countermeasure mechanism. The extensibility of spatiotemporal sequences ensures the unity and continuity of spatial (re)production of NUDs. However, this is also facing a series of challenges like the management coordination of administrative division and the increasing unbalanced or inadequate development. Thus, critically rethinking the evolution of NUD is the key basis for achieving sustainable urban renewal and regional orderly development in the new era.

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    Beautiful China Initiative: Human-nature harmony theory, evaluation index system and application
    FANG Chuanglin, WANG Zhenbo, LIU Haimeng
    Journal of Geographical Sciences    2020, 30 (5): 691-704.   doi: 10.1007/s11442-020-1750-7
    Abstract141)   HTML5)    PDF (3207KB)(10)      

    The Beautiful China Initiative (BCI) is a plan for the sustainable development of the Chinese nation as well as for China to fulfill the United Nations’ 2030 Agenda for Sustainable Development. The Chinese government’s “five-in-one” approach provides strategic arrangements for developing the BCI, and President Xi Jinping proposed a timetable and “road map” for the BCI at the National Conference on Ecological and Environmental Protection. Nevertheless, the theoretical basis, evaluation index system, evaluation criteria and effectiveness of the BCI are currently unclear. This paper begins by exploring the basic content of the BCI from narrow and broad perspectives. It regards the theory of human-nature harmonious coexistence and the five-in-one beauty theory as the core theoretical bases of the BCI and constructs a five-element BCI evaluation index system (ecological environment, green development, social harmony, system perfection and cultural heritage) and utilizes the assessment method of the United Nations’ Human Development Index to assess scientifically the effectiveness of the BCI in 341 prefecture-level cities. The results show the average BCI index (the Chinese Academy of Sciences Beauty Index) score to be 0.28, which is quite low, while the average scores for the individual element indexes of the ecological environment index, green development index, social harmony index, system perfection index and cultural heritage index are 0.6, 0.22, 0.29, 0.22 and 0.07, respectively. All of these are relatively low values, with relatively large discrepancies in regional development, indicating that progress in the BCI is generally slow and unbalanced. To realize the BCI’s timetable and roadmap to a high quality and high standard, it is suggested that a common system for evaluating the progress of the BCI is developed and promulgated so that dynamic monitoring and phased evaluations can take place; BCI technical assessment standards are compiled and published; BCI comprehensive zoning is undertaken; pilot projects adapted to local conditions are launched in BCI sample areas; and BCI results are incorporated into performance indicators at all levels of government.

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    Spatial distribution characteristics of national protected areas in China
    XU Baicui, PAN Jinghu
    Journal of Geographical Sciences    2019, 29 (12): 2047-2068.   doi: 10.1007/s11442-019-1704-0
    Abstract138)   HTML8)    PDF (1479KB)(174)      

    This paper investigated spatial structures of 3418 national protected areas (NPAs) grouped into 13 types using GIS and quantitative analysis, including point patterns, Ripley’s K function, hotspot clustering, quadrat analysis, and Gini coefficient. Spatial accessibility was calculated for all NPAs from matrix raster data using cost weighted distance on the ArcGIS platform. The results are as follows: (1) The NNI of NPAs is 0.515, Gini is 0.073, all of which indicates distribution was shown to be a spatially dependent agglomeration, and more balanced in the provinces. The national key parks and the national water conservancy scenic spots had present the strongest aggregation, with NNI of 0.563 and 0.561 respectively, and K index indicates reducing aggregation when distance exceeds 600 km. (2) The national forest parks account for the largest proportion of 22.87% of all NPAs, and the world biosphere reserves the least of 0.77%. The number of NPAs in Shandong with 240 had been the largest one in all the provinces, while Tianjin had the least number including 9 NPAs. (3) There is only one hot spot in the first-class zone, 5 in the second-class zones, and 51 in the third-class zones, which indicates NPAs are also aggregated at microscopic scales. (4) The hotspot NPA regions were mainly concentrated in the middle and lower reaches of the Yellow and Yangtze rivers, east of 100°E. High density of NPAs were generally in flat, water-rich, broad-leaved forest dominated plains and low mountain areas, with fertile soil, pleasant weather, long cultural history, and high transportation accessibility. (5) Average NPA accessible time is 60.05 min, with 70.76% regions being within 60 min, and the furthest was 777 min. The distribution of accessibility was positively related to the traffic lines. Interdepartmental protectionism has meant the various departments developed different management systems, standards, and technical specifications.

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    Multi-scale analysis of the spatial structure of China’s major function zoning
    WANG Yafei, FAN Jie
    Journal of Geographical Sciences    2020, 30 (2): 197-211.   doi: 10.1007/s11442-020-1723-x
    Abstract133)   HTML13)    PDF (2054KB)(35)      

    The spatial structures of China’s Major Function Zoning are important constraining indicators in all types of spatial planning and key parameters for accurately downscaling major functions. Taking the proportion of urbanization zones, agricultural development zones and ecological security zones as the basic parameter, this paper explores the spatial structures of major function zoning at different scales using spatial statistics, spatial modeling and landscape metrics methods. The results show: First, major function zones have spatial gradient structures, which are prominently represented by latitudinal and longitudinal gradients, a coastal distance gradient, and an eastern-central-western gradient. Second, the pole-axis system structure and core-periphery structure exist at provincial scales. The general principle of the pole-axis structure is that as one moves along the distance axis, the proportion of urbanization zones decreases and the proportion of ecological security zones increases. This also means that the proportion of different function zones has a ring-shaped spatial differentiation principle with distance from the core. Third, there is a spatial mosaic structure at the city and county scale. This spatial mosaic structure has features of both spatial heterogeneity, such as agglomeration and dispersion, as well as of mutual, adjacent topological correlation and spatial proximity. The results of this study contribute to scientific knowledge on major function zones and the principles of spatial organization, and it acts as an important reference for China’s integrated geographical zoning.

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    Urban expansion patterns and their driving forces based on the center of gravity-GTWR model: A case study of the Beijing-Tianjin-Hebei urban agglomeration
    WANG Haijun, ZHANG Bin, LIU Yaolin, LIU Yanfang, XU Shan, ZHAO Yuntai, CHEN Yuchen, HONG Song
    Journal of Geographical Sciences    2020, 30 (2): 297-318.   doi: 10.1007/s11442-020-1729-4
    Abstract133)   HTML3)    PDF (3653KB)(24)      

    Research into urban expansion patterns and their driving forces is of great significance for urban agglomeration development planning and decision-making. In this paper, we reveal the multi-dimensional characteristics of urban expansion patterns, based on the intensity index of the urban expansion, the differentiation index of the urban expansion, the fractal dimension index, the land urbanization rate, and the center of gravity model, by taking the Beijing-Tianjin-Hebei (Jing-Jin-Ji) urban agglomeration as an example. We then build the center of gravity-geographically and temporally weighted regression (GTWR) model by coupling the center of gravity model with the GTWR model. Through the analysis of the temporal and spatial patterns and by using the center of gravity-GTWR model, we analyze the driving forces of the urban land expansion and summarize the dominant development modes and core driving forces of the Jing-Jin-Ji urban agglomeration. The results show that: 1) Between 1990 and 2015, the expansion intensity of the Jing-Jin-Ji urban agglomeration showed a down-up-down trend, and the peak period was in 2005-2010. Before 2005, high-speed development took place in Beijing, Tianjin, Baoding, and Langfang; after 2005, rapid development was seen in Xingtai and Handan. 2) Although the barycenter of cities in the Jing-Jin-Ji urban agglomeration has shown a divergent trend, the local interaction between cities has been enhanced, and the driving forces of urban land expansion have shown a characteristic of spatial spillover. 3) The spatial development mode of the Jing-Jin-Ji urban agglomeration has changed from a dual-core development mode to a multi-core development mode, which is made up of three functional cores: the transportation core in the northern part, the economic development core in the central part, and the investment core in the southern part. The synergistic development between each functional core has led to the multi-core development mode. 4) The center of gravity-GTWR model combines the analysis of spatial and temporal nonstationarity with urban spatial interaction, and analyzes the urban land expansion as a space-time dynamic system. The results of this study show that the model is a feasible approach in the analysis of the driving forces of urban land expansion.

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    Spatiotemporal changes in the bud-burst date of herbaceous plants in Inner Mongolia grassland
    TAO Zexing, DAI Junhu, WANG Huanjiong, HUANG Wenjie, GE Quansheng
    Journal of Geographical Sciences    2019, 29 (12): 2122-2138.   doi: 10.1007/s11442-019-1708-9
    Abstract126)   HTML2)    PDF (1869KB)(61)      

    Phenological modeling is not only important for the projection of future changes of certain phenophases but also crucial for systematically studying the spatiotemporal patterns of plant phenology. Based on ground phenological observations, we used two existing temperature-based models and 12 modified models with consideration of precipitation or soil moisture to simulate the bud-burst date (BBD) of four common herbaceous plants—Xanthium sibiricum, Plantago asiatica, Iris lactea and Taraxacum mongolicum—in temperate grasslands in Inner Mongolia. The results showed that (1) increase in temperature promoted the BBD of all species. However, effects of precipitation and soil moisture on BBD varied among species. (2) The modified models predicted the BBD of herbaceous plants with R 2 ranging from 0.17 to 0.41 and RMSE ranging from 9.03 to 11.97 days, better than classical thermal models. (3) The spatiotemporal pattern of BBD during 1980-2015 showed that species with later BBD, e.g. X. sibiricum (mean: day of year 135.30) exhibited an evidently larger spatial difference in BBD (standard deviation: 13.88 days) than the other species. Our findings suggest that influences of temperature and water conditions need to be considered simultaneously in predicting the phenological response of herbaceous plants to climate change.

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    The impact of economic agglomeration on water pollutant emissions from the perspective of spatial spillover effects
    ZHOU Kan, LIU Hanchu, WANG Qiang
    Journal of Geographical Sciences    2019, 29 (12): 2015-2030.   doi: 10.1007/s11442-019-1702-2
    Abstract124)   HTML5)    PDF (585KB)(112)      

    Whether economic agglomeration can promote improvement in environmental quality is of great importance not only to China’s pollution prevention and control plans but also to its future sustainable development. Based on the COD (Chemical Oxygen Demand) and NH3-N (Ammonia Nitrogen) emissions Database of 339 Cities at the city level in China, this study explores the impact of economic agglomeration on water pollutant emissions, including the differences in magnitude of the impact in relation to city size using an econometric model. The study also examines the spillover effect of economic agglomeration, by conducting univariate and bivariate spatial autocorrelation analysis. The results show that economic agglomeration can effectively reduce water pollutant emissions, and a 1% increase in economic agglomeration could lead to a decrease in COD emissions by 0.117% and NH3-N emissions by 0.102%. Compared with large and megacities, economic agglomeration has a more prominent effect on the emission reduction of water pollution in small- and medium-sized cities. From the perspective of spatial spillover, the interaction between economic agglomeration and water pollutant emissions shows four basic patterns: high agglomeration-high emissions, high agglomeration-low emissions, low agglomeration-high emissions, and low agglomeration-low emissions. The results suggest that the high agglomeration-high emissions regions are mainly distributed in the Beijing-Tianjin-Hebei region, Shandong Peninsula, and the Harbin-Changchun urban agglomeration; thus, local governments should consider the spatial spillover effect of economic agglomeration in formulating appropriate water pollutant mitigation policies.

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    From earth observation to human observation: Geocomputation for social science
    LI Deren, GUO Wei, CHANG Xiaomeng, LI Xi
    Journal of Geographical Sciences    2020, 30 (2): 233-250.   doi: 10.1007/s11442-020-1725-8
    Abstract122)   HTML2)    PDF (4509KB)(15)      

    It is possible to obtain vast amounts of spatiotemporal data related to human activities to support the study of human behavior and social evolution. In this context, geography, with the human-nature relationship as its core, is undergoing a transition from strictly earth observations to the observation of human activities. Geocomputation for social science is one manifestation thereof. Geocomputation for social science is an interdisciplinary approach combining remote sensing techniques, social science, and big data computation. Driven by the availability of spatially and temporally expansive big data, geocomputation for social science uses spatiotemporal statistical analyses to detect and analyze the interactions between human behavior, the natural environment, and social activities; Remote sensing (RS) observations are used as primary data. Geocomputation for social science can be used to investigate major social issues and to assess the impact of major natural and societal events, and will surely be an area of focused development in geography in the near future. We briefly review the background of geocomputation in the social sciences, discuss its definition and disciplinary characteristics, and highlight the main research foci. Several key technologies and applications are also illustrated with relevant case studies of the Syrian Civil War, typhoon transits, and traffic patterns.

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    Geomorphological regionalization theory system and division methodology of China
    WANG Nan, CHENG Weiming, WANG Baixue, LIU Qiangyi, ZHOU Chenghu
    Journal of Geographical Sciences    2020, 30 (2): 212-232.   doi: 10.1007/s11442-020-1724-9
    Abstract117)   HTML4)    PDF (702KB)(33)      

    Geomorphological regionalization (geomor-region) and geomorphological type (geomor-type) classification are two core components in the geomorphologic research. Although remarkable achievements have been made in the study of geomor-region, many deficiencies still exist, such as the inconsistency of landform indicators, the small quantity of division orders, disparities of geomorphological characteristics, differences of mapping results, and the small scale of zoning maps. Requirements for improved national geomor-regions are therefore needed for the purpose of an enhanced national geo-information system. Based on theories of geomor-region in China including plate tectonics, crustal features, endogenic and exogenic forced geomorphological features, and regional differentiations of geomor-type, a three-order (major-region, sub-region, and small-region) research program on China’s geomor-regions is proposed on the basis of previous 2013 geomor-region system. The major contents of the new geomor-region scheme are: (1) principles of the national multi-order geomor-regions; (2) hierarchical indicator systems of geomor-regions including characteristics of the terrain ladder under the control of tectonic setting, combinations of regional macro-form types, combinations of endogenic and exogenic forces and basic types of morphology, combinations of regional morphological types, and combinations of regional micro-morphological types; (3) naming rules and coding methods of geomor-regions; and (4) precise positioning techniques and methods of multi-order geomor-region divisions based on multi-source data. Using the new geomor-region theory and division methodology, the partition of national three-order geomor-regions of China was successfully constructed. The geomor-region system divided China into six first-order major-regions, 36 second-order sub-regions, and 136 third-order small-regions. In addition, a database and management information system of the national geomor-regions were established. This research has an important guiding significance for promoting the development of China’s regional geomorphology and for practical applications based on geomor-regions.

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    Compilation of 1:50,000 vegetation type map with remote sensing images based on mountain altitudinal belts of Taibai Mountain in the North-South transitional zone of China
    YAO Yonghui, SUONAN Dongzhu, ZHANG Junyao
    Journal of Geographical Sciences    2020, 30 (2): 267-280.   doi: 10.1007/s11442-020-1727-6
    Abstract113)   HTML6)    PDF (4024KB)(18)      

    The compilation of 1:250,000 vegetation type map in the North-South transitional zone and 1:50,000 vegetation type maps in typical mountainous areas is one of the main tasks of Integrated Scientific Investigation of the North-South Transitional Zone of China. In the past, vegetation type maps were compiled by a large number of ground field surveys. Although the field survey method is accurate, it is not only time-consuming, but also only covers a small area due to the limitations of physical environment conditions. Remote sensing data can make up for the limitation of field survey because of its full coverage. However, there are still some difficulties and bottlenecks in the extraction of remote sensing information of vegetation types, especially in the automatic extraction. As an example of the compilation of 1:50,000 vegetation type map, this paper explores and studies the remote sensing extraction and mapping methods of vegetation type with medium and large scales based on mountain altitudinal belts of Taibai Mountain, using multi-temporal high resolution remote sensing data, ground survey data, previous vegetation type map and forest survey data. The results show that: 1) mountain altitudinal belts can effectively support remote sensing classification and mapping of 1:50,000 vegetation type map in mountain areas. Terrain constraint factors with mountain altitudinal belt information can be generated by mountain altitudinal belts and 1:10,000 Digital Surface Model (DSM) data of Taibai Mountain. Combining the terrain constraint factors with multi-temporal and high-resolution remote sensing data, ground survey data and previous small-scale vegetation type map data, the vegetation types at all levels can be extracted effectively. 2) The basic remote sensing interpretation and mapping process for typical mountains is interpretation of vegetation type-groups→interpretation of vegetation formation groups, formations and subformations→interpretation and classification of vegetation types & subtypes, which is a combination method of top-down method and bottom-up method, not the top-down or the bottom-up classification according to the level of mapping units. The results of this study provide a demonstration and scientific basis for the compilation of large and medium scale vegetation type maps.

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    Application of an evaluation method of resource and environment carrying capacity in the adjustment of industrial structure in Tibet
    NIU Fangqu, YANG Xinyu, ZHANG Xiaoping
    Journal of Geographical Sciences    2020, 30 (2): 319-332.   doi: 10.1007/s11442-020-1730-y
    Abstract111)   HTML3)    PDF (593KB)(14)      

    With the degradation of natural resources and environment caused by industrial development in some developing countries, the requirement of implementing a “social ecological” approach to development is imminent. Resource and environment carrying capacity provides a means of assessing regional development potential by measuring regional sustainable development in terms of economy, population and resources & environment. This study develops a conceptual framework for resource and environment carrying capacity estimation to support the co-development planning of industries, population and resources & environment. First, the framework constructs an index system for evaluating importance of industry or influence based on the role of industry played in the local socio-economic system. Then, the framework computes the quantitative relations through the importance of local industry, population size and resource utilization and environment effects, and subsequently estimates the resource and environment carrying capacity of the study area. With a particular attention to its land resources, water resources and environment, the Tibet case study shows that: the non-ferrous metal mining, tourism, liquor and refined tea industries play a pillar role in the Tibet’s socio-economic system; under each industrial structure, land resource carrying capacity is the weakest, and water resources carrying capacity is the strongest; to focus on tourism will improve local resource and environment carrying capacity. The research results provide a solid guide for Tibet government’s co-actions in industrial restructuring, ecological protection, and the pursuit of economic development. This study will contribute to bridge the gap between theoretical research and practical applications of resource and environment carrying capacity, and help local governments plan the regional “socio-ecological” sustainable development.

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    Dynamics of shoreline and land reclamation from 1985 to 2015 in the Bohai Sea, China
    DING Xiaosong, SHAN Xiujuan, CHEN Yunlong, JIN Xianshi, MUHAMMED Forruq Rahman
    Journal of Geographical Sciences    2019, 29 (12): 2031-2046.   doi: 10.1007/s11442-019-1703-1
    Abstract108)   HTML2)    PDF (851KB)(123)      

    Extraction and analysis of the shoreline and land reclamation patterns are important for studies on topics such as the dynamics of coastal wetland ecological environments, transportation and exchange of material energy in coastal regions, and recruitment of fishery resources. Spatial-temporal variations in the shoreline and land reclamation in the Bohai Sea were analyzed based on 49 Landsat images of 7 periods from 1985 to 2015. The following conclusions were drawn. (1) The extracted shoreline data based on visual interpretation had high precision, and the shoreline extraction errors could be controlled within the theoretical range. (2) Over the past 30 years, the shoreline of the Bohai Sea has exhibited an average rate of change of 188.47 m/a and an average accretion distance of 3.55×10 3 m toward the sea. The fastest rate of shoreline change occurred in Laizhou Bay (134.78 m/a), followed by Bohai Bay (128.20 m/a) and Liaodong Bay (61.69 m/a). (3) The average rate of reclamation was 3.25×10 4 ha/a in the Bohai Sea, where the total area of aquaculture land, unused land, and salt land exceeded 60% of the total reclamation area. (4) The geometric shape of the bay became increasingly complicated from year to year, and the geometric center of gravity of the bay moved rapidly toward the sea. In addition, the area of the bay showed a significant decreasing trend. Therefore, to protect the function and structure of the ecosystem in coastal regions, we must control the scale and rate of land reclamation in the future.

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    Does geographic distance have a significant impact on enterprise financing costs?
    SUN Wei, LI Qihang, LI Bo
    Journal of Geographical Sciences    2019, 29 (12): 1965-1980.   doi: 10.1007/s11442-019-1699-6
    Abstract105)   HTML10)    PDF (465KB)(118)      

    As information technology has been applied more broadly and transportation infrastructure has improved, persistent debate has existed as to the question of whether geographic distance influences enterprise financing costs (EFCs). Through mining big data regarding industrial enterprises and commercial bank branches (CBBs) in the Beijing-Tianjin-Hebei region, this paper conducts quantitative analysis of correlation between the EFCs and their distance to CBBs as well as the number of CBBs within a 1-5 km radius, and investigates how geographic factors affect EFCs. The results indicate the following: (1) In overall terms, the shorter the distance to CBBs and the greater the number of CBBs within a 1-5 km radius, the lower the EFCs. (2) Distance to CBBs and number of CBBs within a 1-5 km radius significantly influence state-owned and non-state-owned enterprises, with the effect on non-state-owned enterprises being more pronounced. (3) The EFCs in Beijing and Tianjin are not correlated with distance to CBBs, and negatively correlated to the number of CBBs within a 1-5 km radius; the EFCs in Hebei Province are positively correlated with distance to CBBs, and negatively correlated with the number of CBBs within a 1-5 km radius. (4) Distance to CBBs has a more significant impact on enterprises engaged in heavy industry and labor-intensive industries, while there is not much difference between different industries in terms of how the number of CBBs within a 1-5 km radius affects them.

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    Dynamic simulation of urbanization and eco-environment coupling: Current knowledge and future prospects
    CUI Xuegang, FANG Chuanglin, LIU Haimeng, LIU Xiaofei, LI Yonghong
    Journal of Geographical Sciences    2020, 30 (2): 333-352.   doi: 10.1007/s11442-020-1731-x
    Abstract105)   HTML1)    PDF (390KB)(20)      

    Urbanization and eco-environment coupling is a research hotspot. Dynamic simulation of urbanization and eco-environment coupling needs to be improved because the processes of coupling are complex and statistical methods are limited. Systems science and cross-scale coupling allow us to define the coupled urbanization and eco-environment system as an open complex giant system with multiple feedback loops. We review the current state of dynamic simulation of urbanization and eco-environment coupling and find that: (1) The use of dynamic simulation is an increasing trend, the relevant theory is being developed, and modeling processes are being improved; (2) Dynamic simulation technology has become diversified, refined, intelligent and integrated; (3) Simulation is mainly performed for three aspects of the coupling, multiple regions and multiple elements, local coupling and telecoupling, and regional synergy. However, we also found some shortcomings: (1) Basic theories are inadequately developed and insufficiently integrated; (2) The methods of unifying systems and sharing data are behind the times; (3) Coupling relations and the dynamic characteristics of the main driving elements are not fully understood or completely identified. Additionally, simulation of telecoupling does not quantify parameters and is not systemically unified, and therefore cannot be used to represent spatial synergy. In the future, we must promote communication between research networks, technology integration and data sharing to identify the processes governing change in coupled relations and in the main driving elements in urban agglomerations. Finally, we must build decision support systems to plan and ensure regional sustainable urbanization.

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    Spatio-temporal evolution and influencing factors of urban green development efficiency in China
    ZHOU Liang, ZHOU Chenghu, CHE Lei, WANG Bao
    Journal of Geographical Sciences    2020, 30 (5): 724-742.   doi: 10.1007/s11442-020-1752-5
    Abstract101)   HTML2)    PDF (876KB)(11)      

    To resolve conflicts between development and the preservation of the natural environment, enable economic transformation, and achieve the global sustainable development goals (SDGs), green development (GD) is gradually becoming a major strategy in the construction of an ecological civilization and the ideal of building a “beautiful China”, alongside the transformation and reconstruction of the global economy. Based on a combination of the concept and implications of GD, we first used the Slacks Based Model with undesirable outputs (SBM-Undesirable), the Theil index, and the spatial Markov chain to measure the spatial patterns, regional differences, and spatio-temporal evolution of urban green development efficiency (UGDE) in China from 2005 to 2015. Second, by coupling natural and human factors, the mechanism influencing UGDE was quantitatively investigated under the framework of the human-environment interaction. The results showed that: (1) from 2005 to 2015, the UGDE increased from 0.475 to 0.523, i.e., an overall increase of 10%. In terms of temporal variation, there was a staged increase, with its evolution having the characteristics of a “W-shaped” pattern. (2) The regional differences in UGDE followed a pattern of eastern > central > western. For different types of urban agglomeration, the UGDE had inverted pyramid cluster growth characteristics that followed a pattern of “national level > regional level > local level”, forming a stable hierarchical scale structure of “super cities > mega cities > big cities > medium cities > small cities”. (3) UGDE in China has developed with significant spatial agglomeration characteristics. High-efficiency type cities have positive spillover effects, while low-efficiency cities have negative effects. Different types of urban evolution processes have a path dependence, and a spatial club convergence phenomenon exists, in which areas with high UGDE are concentrated and drive low UGDE elsewhere. (4) Under the framework of regional human-environment interaction, the degree of human and social influence on UGDE is greater than that of the natural background. The economic strength, industrial structure, openness, and climate conditions of China have positively promoted UGDE.

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    Moisture sources of the Alashan Sand Seas in western Inner Mongolia, China during the Last Glacial Maximum and mid-Holocene: Interpretation from modern analogues, paleoclimatic simulations and geological records
    FENG Yingying, YANG Xiaoping
    Journal of Geographical Sciences    2019, 29 (12): 2101-2121.   doi: 10.1007/s11442-019-1707-x
    Abstract99)   HTML4)    PDF (23079KB)(47)      

    Knowledge of moisture sources is of great significance for understanding climatic change and landscape evolution in desert environments. In this paper, we aim to clarify moisture origins for the Alashan (Alxa) Sand Seas (ALSS) in western Inner Mongolia and their transport pathways during the Last Glacial Maximum (LGM) and the mid-Holocene using modern analogues and paleoclimatic simulations. Precipitation data for the period 1959-2015 from meteorological stations in the study area and wind and specific humidity data from the European Center for Medium-Range Weather Forecasts (ECMWF) daily reanalysis were adopted to determine the moisture sources of summer precipitation in the ALSS. In addition paleoclimate simulations under PMIP3/CMIP5 protocols were used to detect the atmospheric circulation and precipitation at 21 ka BP and 6 ka BP over the ALSS. We also reviewed paleoclimate records from the ALSS to acquire a semi-quantitative reconstruction of the moisture history during the late Pleistocene and Holocene. Our results suggest that the summer monsoon transported water vapor from the Indian Ocean and the South China Sea to the ALSS during July and August, causing increased precipitation. The dominant moisture source was from the southwest monsoon, while the East Asian summer monsoon also partly contributed to precipitation in the ALSS. The increased humidity during the period 8.2-4.2 ka BP in the ALSS, as derived from both climate simulation outputs and sedimentary records, was caused by monsoons according to the outputs of simulations. At 21 ka BP, the moisture sources of the ALSS were greatly associated with the prevailing westerlies.

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    Geographical thoughts on the relationship between ‘Beautiful China’ and land spatial planning
    CHEN Mingxing, LIANG Longwu, WANG Zhenbo, ZHANG Wenzhong, YU Jianhui, LIANG Yi
    Journal of Geographical Sciences    2020, 30 (5): 705-723.   doi: 10.1007/s11442-020-1751-6
    Abstract96)   HTML4)    PDF (1926KB)(17)      

    The concept of ‘Beautiful China’ is a new goal of ecological construction in the new era of socialism and aims to meet the needs of people as they strive for a better life. National land spatial planning is one major component of the Chinese state’s overall planning for various spatial types. The concept of ‘Beautiful China’ is thus a leading goal of Chinese development in the second centenary. The background of this concept aims for ‘ecological beauty’ as well as the combined beauty of ‘economy-politics-culture-society-ecology.’ The construction of ‘Beautiful China’ therefore necessitates a differentiated evaluation index system that is built on the basis of local conditions. This concept is intimately related to land spatial planning and the idea of Beautiful China guides an important direction for this planning which itself provides an important mechanism and spatial guarantee for construction. The establishment of land spatial planning nevertheless needs to strengthen further discussion of the regional system of human-land relationship, point axis system, main functional division, sustainable development, resources and environmental carrying capacity as well as new urbanization, and the rural multi-system. The aim of this paper is to summarize current thinking in land spatial planning, scientifically analyze the natural geographical conditions, the socioeconomic development, the interrelationship of the land space, plan the goal, vision and path of land space, encourage the public to participate in and carry out dynamic evaluation, build an intelligent system platform for land and spatial planning to realize the goal of ‘Beautiful China’ from a geographical perspective. And they can also present key ideas relating to the compilation and implementation of land spatial planning.

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    Scenarios of land cover in Eurasia under climate change
    FAN Zemeng, BAI Ruyu, YUE Tianxiang
    Journal of Geographical Sciences    2020, 30 (1): 3-17.   doi: 10.1007/s11442-020-1711-1
    Abstract95)   HTML1)    PDF (1620KB)(66)      

    The method for surface modelling of land cover scenarios (SMLCS) has been improved to simulate the scenarios of land cover in Eurasia. On the basis of the observation monthly climatic data observed from 2127 weather stations in Eurasia during 1981-2010, the climatic scenarios data of RCP26, RCP45 and RCP85 scenarios released by CMIP5, and the land cover current data of Eurasia in 2010, the land cover scenarios of Eurasia were respectively simulated. The results show that most land cover types would generally have similar changing trends in the future, but with some difference in different periods under the three scenarios of RCP26, RCP45 and RCP85. Deciduous needleleaf forest, mixed forest, shrub land, wetlands and snow and ice would generally decrease in Eurasia during 2010-2100. Snow and ice would have the fastest decreasing rate that would decrease by 37.42% on average. Shrub land would have the slowest decreasing rate that would decrease by 5.65% on average. Water bodies would have the fastest increasing rate that would increase by 28.78% on average. Barren or sparsely vegetated land would have the slowest increasing rate that would increase by 0.76%. Moreover, the simulated results show that climate change would directly impact on land cover change in Eurasia.

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    Traditional agroecosystem transition in mountainous area of Three Gorges Reservoir Area
    LIANG Xinyuan, LI Yangbing, SHAO Jing’an, RAN Caihong
    Journal of Geographical Sciences    2020, 30 (2): 281-296.   doi: 10.1007/s11442-020-1728-5
    Abstract95)   HTML1)    PDF (4366KB)(24)      

    The Three Gorges Reservoir Area (TGRA) is typical of an ecologically vulnerable area, comprised of rural and mountainous areas, and with high immigration. Because of its economic and ecologic importance, studying the traditional agroecosystem changes in the TGRA is key to rural development and revitalization. In this study, we apply a framework of theoretical analysis, empirical study, and trend prediction to the Caotangxi River watershed within the TGRA. Using QuickBird high-resolution remote sensing images from 2012 to 2017 to evaluate natural resources and farmers’ behavior, we analyze the transition and trends in the traditional agroecosystem in mountainous areas of the TGRA at spatial scale of the man-land relationship. We find that the agroecosystem in the TGRA can be divided into four modes using 100 m interval buffer rings: high-low-low, high-low-high, low-high-low and low-low-high mode where the different modes represent the agricultural development stages in the TGRA. Furthermore, the traditional agroecosystem in TGRA, represented by system elements such as farmers and sloping farmland, is transforming to accommodate the diversification of farmer livelihoods. For example, sloping farmland, which was dominated by a production function, now has equal emphasis on ecological and economic functions. Spatially, the range of the agroecosystem transition has migrated beyond high mountain areas to flat valley areas. Generally, this study provides an overview of land use in rural areas, controls on soil and water loss in mountainous areas, and better rural living environments in the TGRA.

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    Impact of climate change on Tibet tourism based on tourism climate index
    ZHONG Linsheng, YU Hu, ZENG Yuxi
    Journal of Geographical Sciences    2019, 29 (12): 2085-2100.   doi: 10.1007/s11442-019-1706-y
    Abstract93)   HTML6)    PDF (16207KB)(116)      

    Climate change is an important factor affecting the sustainable development of tourist destinations. Based on the monthly observation data of the main meteorological stations on the ground in Tibet from 1960 to 2015, this paper constructs a tourism climate index model. This index is used to quantitatively evaluate the tourism climate changes in Tibet, and investigate the impact of climate change on tourism. The results show that from 1960 to 2015, the temperature in Tibet increased by 1.35°C, and the tourism climate index changed significantly, especially in the regions of Changtang, Ngari and Kunlun Mountain. The fluctuation of temperature-humidity index, wind-chill index and index of clothing of these areas was larger than that of other regions. The changes of each index in different months are different, where spring observes larger changes while summer observes smaller changes. The tourism climate index in northwestern Tibet has increased, and the climate comfort period is expanding. In southeastern Tibet, the comfort level has declined and the comfort level in the central part has been slowly increasing. The comfort index in the southeastern part of Tibet has gradually declined, and the comfort index in central Tibet has slowly increased. According to the comprehensive assessment method including temperature and humidity index, wind-chill index, index of clothing and altitude adaptability index, the types of tourism climate index in Tibet can be divided into reduced, low-speed growth, medium-speed growth and rapid growth. Different regions should adopt alternative tourism products, strengthen energy conservation and emission reduction technology applications and green infrastructure construction, and appropriately control the scale of tourism activities so as to adapt to and mitigate the impact of climate change on tourist destinations.

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    Spatiotemporal evolution of urban carbon emission performance in China and prediction of future trends
    WANG Shaojian, GAO Shuang, HUANG Yongyuan, SHI Chenyi
    Journal of Geographical Sciences    2020, 30 (5): 757-774.   doi: 10.1007/s11442-020-1754-3
    Abstract93)   HTML0)    PDF (1602KB)(4)      

    Climate change resulting from CO2 emissions has become an important global environmental issue in recent years. Improving carbon emission performance is one way to reduce carbon emissions. Although carbon emission performance has been discussed at the national and industrial levels, city-level studies are lacking due to the limited availability of statistics on energy consumption. In this study, based on city-level remote sensing data on carbon emissions in China from 1992-2013, we used the slacks-based measure of super-efficiency to evaluate urban carbon emission performance. The traditional Markov probability transfer matrix and spatial Markov probability transfer matrix were constructed to explore the spatiotemporal evolution of urban carbon emission performance in China for the first time and predict long-term trends in carbon emission performance. The results show that urban carbon emission performance in China steadily increased during the study period with some fluctuations. However, the overall level of carbon emission performance remains low, indicating great potential for improvements in energy conservation and emission reduction. The spatial pattern of urban carbon emission performance in China can be described as “high in the south and low in the north,” and significant differences in carbon emission performance were found between cities. The spatial Markov probabilistic transfer matrix results indicate that the transfer of carbon emission performance in Chinese cities is stable, resulting in a “club convergence” phenomenon. Furthermore, neighborhood backgrounds play an important role in the transfer between carbon emission performance types. Based on the prediction of long-term trends in carbon emission performance, carbon emission performance is expected to improve gradually over time. Therefore, China should continue to strengthen research and development aimed at improving urban carbon emission performance and achieving the national energy conservation and emission reduction goals. Meanwhile, neighboring cities with different neighborhood backgrounds should pursue cooperative economic strategies that balance economic growth, energy conservation, and emission reductions to realize low-carbon construction and sustainable development.

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    Spatio-temporal variation in China’s climatic seasons from 1951 to 2017
    MA Bin, ZHANG Bo, JIA Lige
    Journal of Geographical Sciences    2020, 30 (9): 1387-1400.   doi: 10.1007/s11442-020-1788-6
    Abstract92)   HTML1)    PDF (2155KB)(0)      

    In this paper, meteorological industry standard, daily mean temperature, and an improved multiple regression model are used to calculate China’s climatic seasons, not only to help understand their spatio-temporal distribution, but also to provide a reference for China’s climatic regionalization and crop production. It is found that the improved multiple regression model can accurately show the spatial distribution of climatic seasons. The main results are as follows. There are four climatic seasonal regions in China, namely, the perennial-winter, no-winter, no-summer and discernible regions, and their ranges basically remained stable from 1951 to 2017. The cumulative anomaly curve of the four climatic seasonal regions clarifies that the trend of China’s climatic seasonal regions turned in 1994, after which the area of the perennial-winter and no-summer regions narrowed and the no-winter and discernible regions expanded. The number of sites with significantly reduced winter duration is the largest, followed by the number of sites with increased summer duration, and the number of sites with large changes in spring and autumn is the least. Spring advances and autumn is postponed due to the shortened winter and lengthened summer durations. Sites with significant change in seasonal duration are mainly distributed in Northwest China, the Sichuan Basin, the Huanghe-Huaihe-Haihe (Huang-Huai-Hai) Plain, the Northeast China Plain, and the Southeast Coast.

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    Analysis of critical river discharge for saltwater intrusion control in the upper South Branch of the Yangtze River Estuary
    SUN Zhaohua, FAN Jiewei, YAN Xin, XIE Cuisong
    Journal of Geographical Sciences    2020, 30 (5): 823-842.   doi: 10.1007/s11442-020-1757-0
    Abstract90)   HTML0)    PDF (1785KB)(3)      

    Saltwater intrusion in the estuary area threatens the use of freshwater resources. If river discharge increases to a critical value, then saltwater intrusion frequency and salinity level decreases. In this study, long-term river discharge and tidal range data in the Yangtze River Estuary (YRE) and salinity data obtained in the upper South Branch of the YRE were used to analyze the characteristics of different variables and the basic law of their interactions. Two methods, namely, the material analysis method and empirical models, were applied to determine the critical river discharge for saltwater intrusion control. Results are as follows: (1) the salinity might exceed the drinking water standard of China when the river discharge was less than 30,000 m3/s. Approximately 69% of salinity excessive days occurred when the river discharge was less than 15,000 m3/s; (2) the tidal range in the YRE roughly varied in sinusoidal pattern with a 15-day cycle length. Exponential relationship existed between daily salinity (chlorinity) and daily mean tidal range. Combining these two features with the cumulative frequency statistics of tidal ranges, it was showed that notable saltwater intrusion occurred when the tidal range was more than 2.7 m at Qinglonggang station. Moreover, the critical discharge was found to be slightly higher than 11,000 m3/s; (3) various of empirical models for salinity prediction could be chosen to calculate the critical discharge. The values obtained by different models were in the range of 11,000-12,000 m3/s; (4) the proposed critical discharge to reduce notable saltwater intrusion was 11,500 m3/s. After the Three Gorges Reservoir operation, the minimum river discharge into the YRE in 2008-2017 was below the critical discharge, thereby suggesting an increase in the minimum river discharge by reservoir regulation in drought periods.

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    China’s corridors-in-the-sky design and space-time congestion identification and the influence of air routes’ traffic flow
    DONG Yaqing, LU Zi, LIU Yuan, ZHANG Qiuluan, WU Dianshuang
    Journal of Geographical Sciences    2019, 29 (12): 1999-2014.   doi: 10.1007/s11442-019-1701-3
    Abstract89)   HTML7)    PDF (3088KB)(80)      

    With rapid development of air transportation, the airspace structure of the future will need to be flexible and dynamic to accommodate the increase in traffic demand. The corridors-in-the-sky has become a new technology to support the full exploitation and utilization of airspace resources. This paper proposes a method of designing corridor, identifying congestion state, and analyzing the influence of air routes’ traffic flow. From this, we have reached a number of conclusions. (1) The congestion periods present the multi-peak “wavy” scattered distributions and the peaks back-end agglomeration characteristics in the whole day. (2) The congestion segments present the structural characteristics of unbalanced coverage and concentrated distribution to the crossing points. The corridors with high congestion level present as an italic “N-shaped” frame, which presents incomplete penetration of short segments. (3) For the temporal and spatial interaction, there are two types of congestion segments, and there are some common congestion periods in different congestion segments of multiple corridors. The high-density air route plays a relatively decisive role in corridor congestion, and the influence of two directions is unbalanced. This research can provide a basis for the dynamic evaluation of China’s airspace resources and corridors construction in the future.

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    A comparative study of land price estimation and mapping using regression kriging and machine learning algorithms across Fukushima prefecture, Japan
    DERDOURI Ahmed, MURAYAMA Yuji
    Journal of Geographical Sciences    2020, 30 (5): 794-822.   doi: 10.1007/s11442-020-1756-1
    Abstract86)   HTML2)    PDF (8028KB)(6)      

    Finding accurate methods for estimating and mapping land prices at the macro-scale based on publicly accessible and low-cost spatial data is an essential step in producing a meaningful reference for regional planners. This asset would assist them in making economically justified decisions in favor of key investors for development projects and post-disaster recovery efforts. Since 2005, the Ministry of Land, Infrastructure, and Transport of Japan has made land price data open to the public in the form of observations at dispersed locations. Although this data is useful, it does not provide complete information at every site for all market participants. Therefore, estimating and mapping land prices based on sound statistical theories is required. This paper presents a comparative study of spatial prediction of land prices in 2015 in Fukushima prefecture based on geostatistical methods and machine learning algorithms. Land use, elevation, and socioeconomic factors, including population density and distance to railway stations, were used for modeling. Results show the superiority of the random forest algorithm. Overall, land prices are distributed unevenly across the prefecture with the most expensive land located in the western region characterized by flat topography and the availability of well-connected and highly dense economic hotspots.

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    Paddy rice multiple cropping index changes in Southern China: Impacts on national grain production capacity and policy implications
    JIANG Min, LI Xiubin, XIN Liangjie, TAN Minghong
    Journal of Geographical Sciences    2019, 29 (11): 1773-1787.   doi: 10.1007/s11442-019-1689-8
    Abstract83)   HTML10)    PDF (2615KB)(105)      

    Changes in rice production in Southern China are crucial to national food security. This study employed Landsat images to map the distributions of paddy rice-cropping systems in Southern China in 1990 and 2015. The impact of rice multiple cropping index changes on grain production capacity was then evaluated. Three important results were obtained for the 1990 to 2015 study period. First, the multiple cropping index for rice decreased from 148.3% to 129.3%, and 253.16×10 4 ha of land area was converted from double-cropping to single-cropping rice, termed “double to single”. The area with the most dramatic changes is in the Middle-Lower Yangtze Plain. The rice-cropping system distribution in Southern China showed a change from north to south with double-cropping rice shrinking and single-cropping rice expanding. Second, the “double to single” conversion led to a reduction of 6.1% and 2.6% in rice and grain production, respectively. Hunan and Jiangxi Provinces, located in the main rice producing areas, and Zhejiang, which has shown better economic development, exhibited large reductions in rice production due to the “double to single” conversion, all exceeding 13%. Third, the grain production capacity of converted “double to single” paddy fields is equivalent to that of 223.3 × 10 4 ha of newly reclaimed cultivated land, which is 54% of the total newly cultivated land reclaimed through the 2001-2015 land consolidation project. It is also 1.7 times the target goal for newly cultivated land in the national land consolidation plan for 2016-2020. Making full use of the converted “double to single” paddy fields can save 167.44 billion yuan in newly reclaimed cultivated land costs. Therefore, instead of pursuing low-quality new arable land, it is better to make full use of the existing high-quality arable land. Based on these results, the government should change the assessment method for cultivated land balance, and incorporate the sown area increased by improving the multiple cropping index into the cultivated land compensation indicator.

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    Implications of diurnal variations in land surface temperature to data assimilation using MODIS LST data
    FU Shiwen, NIE Suping, LUO Yong, CHEN Xin
    Journal of Geographical Sciences    2020, 30 (1): 18-36.   doi: 10.1007/s11442-020-1712-0
    Abstract79)   HTML4)    PDF (19310KB)(49)      

    Based on the Beijing Climate Center’s land surface model BCC_AVIM (Beijing Climate Center Atmosphere-Vegetation Interaction Model), the ensemble Kalman filter (EnKF) algorithm has been used to perform an assimilation experiment on the Moderate Resolution Imaging Spectroradiometer (MODIS) land surface temperature (LST) product to study the influence of satellite LST data frequencies on surface temperature data assimilations. The assimilation results have been independently tested and evaluated by Global Land Data Assimilation System (GLDAS) LST products. The results show that the assimilation scheme can effectively reduce the BCC_AVIM model simulation bias and the assimilation results reflect more reasonable spatial and temporal distributions. Diurnal variation information in the observation data has a significant effect on the assimilation results. Assimilating LST data that contain diurnal variation information can further improve the accuracy of the assimilation analysis. Overall, when assimilation is performed using observation data at 6-hour intervals, a relatively good assimilation result can be obtained, indicated by smaller bias (<2.2K) and root-mean-square-error (RMSE) (<3.7K) and correlation coefficients larger than 0.60. Conversely, the assimilation using 24-hour data generally showed larger bias (>2.2K) and RMSE (>4K). Further analysis showed that the sensitivity of assimilation effect to diurnal variations in LST varies with time and space. The assimilation using observations with a time interval of 3 hours has the smallest bias in Oceania and Africa (both<1K); the use of 24-hour interval observation data for assimilation produces the smallest bias (<2.2K) in March, April and July.

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