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    Climate Change
  • Climate Change
    ZHAO Jie,DU Ziqiang,WU Zhitao,ZHANG Hong,GUO Na,MA Zhiting,LIU Xuejia
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    Based on normalized difference vegetation index (NDVI), vegetation type, and meteorological data, this study revealed the seasonal variations of the day- and nighttime warming in growing seasons using unitary linear regression analysis. It examined different effects of asymmetric seasonal warming on vegetation activities in China's temperate zone using the two-order partial correlation analysis method. The results are as follows. (1) The day- and nighttime warming trends from 1982 to 2015 in growing seasons were extremely significant. The day- and nighttime warming rates were featured by asymmetry; daytime warming was slightly faster than nighttime warming in spring and summer. Contrarily, in autumn, nighttime warming was faster than daytime warming. (2) The effects of the day- and nighttime warming on vegetation activity were obviously different; daytime warming had significantly greater and more extensive effects on vegetation than nighttime warming did, and the areas impacted by diurnal warming were broader in spring than in summer and autumn. (3) Different vegetation types responded differently to the seasonal asymmetry in day- and nighttime warming, and the degree of responses showed distinct variations by season.

  • Climate Change
    YIN Zhan'e,TIAN Pengfei,CHI Xiaoxiao
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    Precipitation extremes are expected to become more frequent and intense under global warming in the coming decades. Risk analysis of precipitation extremes has become a hot issue in academic circles and governments. In this paper, we use the data recorded at 756 meteorological stations from 1951 to 2011. Data were first processed to generate a coherent set of precipitation datasets. Pearson-III frequency analysis method was used to define the thresholds of different rainfall return periods. We chose total extreme precipitation amount and extreme precipitation frequency as indices, and scenarios with return periods of 5, 10, 50 and 100 years were designed to analyze precipitation extremes. The vulnerability of economy and population to precipitation extremes was analyzed. Precipitation extremes and the associated vulnerability were evaluated using the risk assessment model of ISDR to assess the risk pattern of precipitation extremes in China, mapping the risk distribution of precipitation extremes under different return periods in China during the past 60 years (1951-2011). Results show that: (1) the magnitude of extreme precipitation decreases from the southeastern coastal areas to the northwestern inlands. The high-risk areas of extreme precipitation in the 5-year scenario are mainly located in southeastern coastal China. The boundary between high-risk and low-risk areas nearly coincides with the isohyet of 400 mm; (2) China's extreme precipitation is mainly observed in densely populated and economically developed eastern coastal metropolitan areas, especially in Yangtze River Delta urban agglomeration, Pearl River Delta urban agglomeration, Beijing-Tianjin-Hebei urban agglomeration and several large cities in the western region of China. The western region of the country, which is resource-scarce and economically less developed, is associated with lower-risk precipitation extremes; (3) under each return period, the extreme precipitation risk level decreases from southeastern coastal areas to northwestern inland areas. The high-risk level areas are distributed in South China, southeastern coastal China, middle and lower reaches of the Yangtze River, Huang-Huai-Hai Plain, Bohai Rim and Sichuan Basin. The areas with high risk are mainly distributed to the east of the Heihe-Tengchong Line (Hu Line), and the medium and low risk areas are located to the west of the Hu Line, which is roughly consistent with the Hu Line of population density distribution in China. This research presents a novel approach to evaluating national-scale precipitation extremes and the associated socio-economic risks. Findings obtained herein can be used as scientific references for governments at all levels in disaster prevention and reduction of extreme precipitation in China.

  • Surface Process and Ecological Environment
  • Surface Process and Ecological Environment
    WANG Shaojian,SU Yongxian,ZHAO Yabo
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    Carbon emissions are increasing due to human activities related with the energy consumptions for economic development. Thus, attention has been paid to the reduction of the growth of carbon emissions and formulation of policies for addressing climate change. Although most studies have explored the driving forces behind carbon emissions in China, literature lacks studies at the city-level due to a limited availability of statistics on energy consumptions. In this study, based on China's city-level remote sensing carbon emissions from 1992 to 2013, we applied the spatial autocorrelation, spatial Markov-chain transitional matrices, dynamic spatial panel model and Sys-GMM to empirically estimate the key determinants of carbon emissions at the city-level and discuss its spatial spillover effects in consideration of spatiotemporal lag effects and different geographical and economic weighting matrices. Results indicated that the regional inequalities of city-level carbon emissions decreased over time and presented an obvious spatial spillover effect and high-emission "club" agglomeration. In addition, the evolution of the emission pattern has the characteristic of obvious path dependence. Panel data analysis results indicated that there was a significant U-shaped curve that can reflect the relationship between carbon emissions and GDP per capita. In addition, carbon emissions per capita are increasing with economic growth for most cities. High-proportion of secondary industry and extensive growth of investment exerted significantly positive effects on China's city-level carbon emissions. Conversely, rapid population agglomeration, the improvement of technology level, the increase of trade openness and road density play an inhibiting role in carbon emissions. Therefore, in order to reduce carbon emissions, the Chinese government should inhibit the effects of promotion factors and enhance the effects of mitigation factors. Combining with the analysis of results, we argued that optimizing the industrial structure, streamlining the extensive investment, increasing the level of technology and improving the road accessibility are the effective ways to increase energy savings and reduce carbon emissions in China.

  • Surface Process and Ecological Environment
    HOU Peng,ZHAI Jun,CAO Wei,YANG Min,CAI Mingyong,LI Jing
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    Ecosystem services have become one of the major aspects of ecosystem management and evaluation. As a key area of ecosystem services, evaluation of ecosystem changes and implementation effect is important for national key ecological function zones. Such evaluation can help to maintain national ecological security, drive the implementation of the main function zone strategy and advance the construction of an ecological civilization. This article explores the ecological zone of a tropical rainforest region in the central mountain area of Hainan Island, China. Multi-source satellite data and ground observation statistics are analyzed with geo-statistics method and ecological assessment model. The core analysis of this paper includes ecosystem pattern, quality and service. By means of spatial and temporal scale expansion and multi-dimensional space-time correlation analysis, we examine the trend and stability characteristics of ecosystem change, and evaluate the implementation effect. The results showed that, first, the forest area ratio was 84.5% in 2013, which was significantly higher than the average level in Hainan Island. During 1990-2013, settlement gradually increased in ecological zone. After the implementation of the function zone in 2010, human activity intensity was still increasing, with the area ratio rising from 0.5% to 0.8%. The main land use change was urban construction and land reclamation. Second, water conservation in the ecological function zone was better than that outside the zone. During 1990-2013, water conservation increased slightly, and had obvious fluctuation in different periods. Water conservation change decreased first and then increased during both the periods 1990-2000 and 2000-2013. Water conservation quantity was 0.5178 million cubic metres per square kilometer, which was higher than the average outside the zone. Third, soil conservation in the ecological function zone was also better than that outside the zone. Soil conservation showed dramatic fluctuations and relatively poor stability during 1990-2013. Soil conservation quantity was 19500 tons per square kilometer in the ecological function zone. Fourth, the human disturbance index in the ecological function zone was significantly less than that outside the zone and had lower biodiversity threat level. This would be beneficial to biodiversity conservation. In the ecological function zone, average human disturbance index was 0.3664 and 0.1152 lower than that outside the zone. During 1990-2013, human disturbance index variation range outside the zone was 0.0152, about 5.31 times that of the inner zone. Especially in 2010-2013, the increased range of human disturbance index in the ecological function zone was significantly less than that outside value the zone.

  • Surface Process and Ecological Environment
    ZHONG Zhangqi,JIANG Lei,HE Lingyun,WANG Zheng,BAI Ling
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    Embodied carbon emissions in international trade plays a crucial role in shaping regional commitments towards emission reduction in the context of global climate change and greenhouse gas emission policy. Based on the multi-region input-output analytical framework and the stochastic impacts by regression on population, affluence and technology (STIRPAT) model, this paper analyzes the embodiment of global emissions in trade, so as to explore the characteristics of global carbon emissions under a consumption accounting principle for 39 countries from 1995 to 2011, and investigates the determinants of the embodied emissions in global trade based on an extended STIRPAT model. One finding from this study is that some countries like China and Russia are characterized by the highest net outflow of embodied emissions in trade, while other regions in the world provide strong support for their economic growth through thick trade relationships, and more importantly, comparative advantages are also obtained by their industries associated with trades. Under the production-based accounting principle, these countries like China and Russia have also been accountable for a large volume of emissions embodied in global trade, and thus would face huge pressures to curtail carbon emissions, which, in turn, may also impede the local economic development. Moreover, the lower the net carbon emissions embodied in regional trade, the higher the carbon emissions under a consumption accounting principle. Therefore, the relevant countries should bear greater emissions reduction responsibilities from the perspective of the production-based accounting principle in the context of global climate policy. Additionally, the analysis results show that a larger deal of net carbon emissions embodied in global trade are mainly from Asia and Eastern Europe, while a smaller amount of net carbon emissions embodied in global trade are primarily found in highly economically developed regions like Western Europe and Northern America. Another important finding is that, for environmental impact analysis regarding the corresponding influencing factors, the increase of carbon emissions embodied in global trade would be primarily caused by population and economic development level. For wealthy countries or regions such as the USA and the EU, via trade relations with their main trading partners, their environmental impacts, particularly carbon emissions associated with their consumption, may be transferred to other regions. On that basis, facing severe pressures to curb carbon emissions embodied in international trade in climate policy, these regions should take proactive initiatives like carrying out technology transfer and/or providing financial aid to improve notably other developing countries' production technology. In addition, in order to reduce the impact of trade on the emissions of global economies on global environment, the increase in the overall share of clean energy in the energy consumption structure and energy efficiency improvement should be also an effective policy option.

  • Surface Process and Ecological Environment
    YANG Siqi,XING Xiaoyue,DONG Weihua,LI Shuaipeng,ZHAN Zhicheng,WANG Quanyi,YANG Peng,ZHANG Yi
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    Abstract: In order to explore the response of influenza A (H1N1) to meteorological factors, we analyzed the spatio-temporal distribution of influenza A (H1N1) in Beijing using global Moran's I and local Getis-Ord G I * . The regression model between influenza A (H1N1) and average wind speed, precipitation, average relative humidity, average temperature was established, based on the geographical weighted regression (GWR) model. The results showed that there was no obvious correlation between influenza A (H1N1) and the precipitation, while a strong positive correlation between influenza A (H1N1) and average wind speed was found. The average temperature and the average relative humidity had a strong negative correlation with the spread of influenza A (H1N1) in Beijing, while the latter presented a more complex impact on the spread of it. In terms of the spatio-temporal variation, the impact of meteorological factors was significant during the period when the number of influenza A (H1N1) infections rose rapidly, while it decreased when the number of infections rose slowly. Regarding the spatial variation, the spatial heterogeneity of the impact of each meteorological factor on the four functional zones of Beijing was obvious, which might be related to regional conditions such as local terrain, wind zone, and local climate.

  • Surface Process and Ecological Environment
    CHEN Rui,LI Fengquan,WANG Tianyang,ZHU Lidong,YE Wei,ZHOU Guocheng
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    Cultural sites are relics of human activity and they are also the product of the interactions between human and nature. The size of cultural sites could reflect the population size and grade of the ancient settlements. The study of cultural sites could help us to deepen the understanding of the relationships between human and nature. This paper established the spatial database of the Neolithic cultural sites in the middle reaches of Yangtze River from 9000 a BP to 4000 a BP. by using ArcGIS software. Overlay analysis and statistical method were employed to examine the spatial relationships between the size of archaeological sites and elevation, slope, the distance to the river in different periods. The results showed that, from the early Neolithic period to the late Neolithic period, the number of sites, the size of sites and the spatial distribution range of the sites showed an increasing or expanding trend, and the proportion of overlapping sites increased; Sites with different sizes generally had low altitude, gentle terrain and near river selection tendency. For sites of the late Neolithic Age, while there existed the above-mentioned selection tendency, the selection of altitude, slope and the distance to river tended to show the characteristics of diversification. There were some differences in location selection of Neolithic cultural sites with different sizes in the late Neolithic period. Small sites were mostly located on the gentle slope of 6-15 degrees. The large or medium-sized sites tended to be distributed on the flat land with a slope of 2-6 degrees; From small to large sites, Neolithic sites was dominated by an elevation of 30-50 m. The elevation of super sites was mainly in a range from 50 m to 100 m. The super sites were located in the area less than 1 km far from the river; The Neolithic culture was greatly influenced by the natural factors such as climate, water resources and topography in the early and middle Neolithic Age, and the adaptation ability of culture in the late Neolithic period was gradually enhanced.

  • Land Use
  • Land Use
    WANG Yahui,LI Xiubin,XIN Liangjie,TAN Minghong,JIANG Min
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    Land circulation is an important measure that can be utilized to enable agricultural management at a moderate scale. It is imperative to explore spatiotemporal changes in land circulation and the factors that drive these variations in order to increase the vitality of land rental market in China. Based on a sample of 169 511 farm households from the rural fixed observation point system between 2003 and 2013, this paper revealed the regional differences in land circulation and used Heckman two-stage models to identify the drivers of regional differences in land circulation. The results of this study show that: (1) the rate of land circulation in China rose from 17.09% to 24.1% over the course of the study period, an average rate of 0.7%. (2) The rate of land circulation in the south of China has been higher than that in the north, the average land rental payment was 283.74 yuan per mu, and 55.05% of farm households did not pay a fee in the process of land circulation. In contrast, the average rent that leasers received was 243.23 yuan per mu nationally even though 52.36% of households did not receive any payments from their tenants. At present, the rate of rent-free land circulation was more than 50% in China's land rental market. In addition, the average rent in developed provinces, such as Jiangsu, Shandong, Guangdong and Zhejiang, was 40% higher than the national average. (3) The results show that land quality, geographic location, transaction costs, and household characteristics have all significantly affected land circulation in different regions of China. The marginal effects of land quality and geographic location were larger in the plain regions, while transaction cost was the key factor influencing land circulation in the hilly and mountainous regions. The essence of rent-free land circulation was a sign of mismatch of land resources, and the marginalization of mountainous regions and higher transaction costs reduced the potential value of land resources. Thus, as the opportunity cost of farming continues to rise across China, the depreciation of land assets will become irreversible and land abandonment will be anabatic in the hills and mountains in the future. The transaction costs in land rental market should be reduced by establishing the land circulation intermediaries at the township level. Also, more attention should be given to the critical issues of farmland abandonment and poverty reduction in the hills and mountains.

  • Land Use
    ZHANG Bailin,GAO Jiangbo,GAO Yang,CAI Weimin,ZHANG Fengrong
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    In agricultural society, the cultivation of mountainous land was a representative of intensified contradiction between human and land which resulted in water loss and soil erosion. With the rapid urbanization and industrialization in poverty-stricken mountainous areas, the labor emigration relieves this contradiction significantly, and leads to land use transition, which results in a series of natural and socio-economic changes. This research built an analysis framework of "Land use transition - driving mechanism - effects - responses" in mountainous land use transition and then put forward the further direction of mountainous land reclamation. The results indicate that: (1) The tendency change of land use morphology was the core of rural land use transition in mountainous areas. The expansion of cropland, as well as the contraction of forest land in agricultural society, has changed to the abandonment of cropland and the expansion of forest land is the main characteristic of the dominant land use morphology transition. Land marginalization and land ecological functional recovery are the main characteristics of the recessive land use morphology transition in mountainous areas. (2) Socio-economic factors are the primary driving forces during the mountainous land use transition. Labor emigration is the direct driving forces. Meanwhile, the rising costs of farming opportunities, and the harsh living environment that lead to labor emigration are the root cause for mountainous land use transition. (3) The transition of rural land use in mountainous areas reduces the vulnerability of land ecosystem and improves its ecological security barrier function. The advantages and disadvantages of its socio-economic effects should focus on rural development of mountainous areas and the livelihood of farmers, and need to be supported by empirical and quantitative researches. (4) The transition of land use in rural areas is a benign process of natural restoration and ecological optimization. The rural land remediation in mountainous areas should conform to the law of land use transition, and the target orientation will shift from the increase of cultivated land to the synergies of ecological and environmental protection.

  • Land Use
    ZHANG Yingnan,LONG Hualou,GE Dazhuan,TU Shuangshuang,QU Yi
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    Taking counties as the basic unit, this paper establishes the evaluation index system of farmland functions from the dimensions of economy, society and ecology, adopts the method combining entropy weighting and multiple correlation coefficient weighting to determine the weights, and calculates the farmland function indices of each county. Subsequently, the spatio-temporal characteristics of farmland functions evolution were analyzed and the coupling relationships between the sub-functions were explored based on the coupling coordination model, simultaneously, the dynamic mechanism of farmland functions evolution was quantitatively probed by applying the spatial econometric regression analysis method in this research. Major conclusions were drawn as follows: (1) The farmland economic function generally presented a declining trend during 1990-2010. Especially, the function is strengthened in underdeveloped and agriculture dominated counties, and weakened continuously in developed areas on contrary; 60.29% of the counties decrease in farmland social function, whereas some counties, which are mostly located in the north of Zhengzhou, the west of Dezhou and Cangzhou, Yantai and Weihai, have experienced an obvious increase; The dramatic decline of farmland ecological function has occurred around Beijing, Tianjin and Jinan. Areas located in northern Henan Province and central Shandong Province has witnessed an increase of ecological function. (2) There is a significant spatial difference in the coupling degree and coordination degree of the sub-functions, and the decoupling phenomenon gradually highlights. The changes of social function and ecological function lag behind those of economic function in developed areas, but they are highly coupled in some underdeveloped areas. (3) The evolution of farmland functions in the Huang-Huai-Hai Plain resulted from the comprehensive effects of regional basic conditions and external driving factors. Furthermore, the transition of population and industry in the process of urbanization and industrialization plays a decisive role in evolution intensity and direction of farmland sub-systems including economy, society and ecology. According to the results above mentioned, agricultural modernization, industrialization and promoting the transformation of traditional agriculture should be regarded as an important engine driving the sustainable development of Huang-Huai-Hai Plain. In view of regional differentiation characteristics of farmland functions evolution, differentiated and diversified farmland use and management modes should be implemented from developed urban areas to underdeveloped traditional agricultural areas.

  • Land Use
    LEI Ming,KONG Xiangbin,WANG Jianing
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    China puts forward the national strategy of fallow plan so as to improve the sustainable grain production capacity of arable land and alleviate the continuous decline of the groundwater level in the Huang-Huai-Hai Plain. Aiming at estimation of sustainable grain productivity for ensuring the implementation of this strategy, this paper learns management experience and experimental production from agricultural experiment station and adopts step-by-step correction method in twelve agricultural ecological zones, which are relatively uniform in social and economic conditions based on the sustainable theory and water balance. The results showed that: (1) The total sustainable grain production capacity of arable land under water balance in the Huang-Huai-Hai Plain was 116 million t/year. (2) The yield gap of sustainable grain productivity was -0.67 million t/year, the wheat yield gap was -3.31 million t/year due to limited-water irrigation and the maize yield gap was positive. (3) The loss area of wheat production is mainly distributed in Heilonggang area, Luxi Plain, the Beijing-Tianjin-Tangshan Plain and the eastern Henan Plain, and the potential area is mainly in Xuhuai Plain, the Northern Anhui Plain and Jiaoxi Yellow River Flood Plain. The research was valuable for understanding the sustainable productivity of cultivated land and implementing the reliable spatial pattern of agricultural production in the Huang-Huai-Hai Plain.

  • Land Use
    WAN Zhiwei,JIA Yulian,JIANG Meixin,LIU Ying,HONG Yijun,LU Chengfang
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    The quantitative reconstruction of historical urban land use and urbanization level data sets can make contribution to good simulation of the environmental effects of land use and cover change. In this study, urban land use and city patterns above or within the county level in Jiangxi Province during the Republican era are reconstructed with the aid of the ArcGIS platform on the basis of the military map during the Japanese invasion of China. A comprehensive data set, which contains the city wall perimeter, urban land area, non-construction land in the city wall, and construction land outside the city wall, is obtained. The data set with a 10% error based on the comparison with detailed data from other studies can be applied to land use models of various historical periods. The county-scale level of land urbanization is analyzed. The "farmland-inside-city" phenomenon occurred in 20 cities, which accounted for 25% of the total number of cities in Jiangxi. The "urban-outside-city" phenomenon is found in 28 cities, which accounted for 35% of the total number of cities in the province. The result shows that the overall area of urban construction was 87.99 km2, which accounted for 0.053% of Jiangxi's total area. The overall urbanization rate of Jiangxi during the Republican era was 0.047%. Of all the cities and counties in the province, Nanchang had the highest urbanization rate (0.19%), whereas Suichuan reached only 0.007%. The urbanization level was positively correlated with the population (r = 0.457, P < 0.001). The data sets of urban land use and urbanization in Jiangxi can provide land use data for relevant global environmental change models.

  • Land Use
    XIONG Ying,CHEN Yun,LI Jingzhi,YAN Xiaojing
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    Using the system dynamics (SD), the feedback loop of urban construction land between supply and demand and function relationship between index variables are built up to simulate the change trends of the balance of land resources supply and demand in Changsha-Zhuzhou-Xiangtan urban agglomeration from 2016 to 2030 in three scenarios, i.e., low intensity mode, medium intensity mode and high intensity mode based on the land resources supply and demand system dynamic model. The simulation suggested that: (1) the construction land scale is still in the expansion state, and the amount of urban construction land is increasing rapidly. However, there are differences in the scale and speed of land use under the three development modes. (2) Under the low intensity mode, the scale of construction land and the quantity of land supply are large, which is prone to the waste of land resources; under the high intensity mode, the supply of construction land is contracted, and the scale of land use is growing slowly and the total scale is small, which is not conducive to the healthy development of new-type urbanization; under the medium intensity mode, the scale of land use and the amount of supply can be adapted to the development of social economy, which can reflect the concept of modern city. (3) The proportion of industrial land to construction land maintains at 15%-21%, in which the proportion under the low intensity mode increases year by year, and slows down and keeps stable under the proper intensity mode and high intensity mode; the proportion of residential land to construction land maintains at 27%-35%, in which the proportion under the low and the medium intensity modes slow down, and the proportion of the high intensity mode keeps at a high level.

  • Progress in Geography
  • Progress in Geography
    HUANG Gengzhi,LENG Shuying
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    This paper analyzes the role of the National Natural Science Foundation of China (NSFC) in promoting the development of Chinese human geography by focusing on five important research areas identified by the recent discipline progress report. They are land use, urban system, economic globalization, climate change and social and cultural geography. The data we use include all NSFC approved proposals on these research areas from 1986 to 2017. The research topic, research content, research team and main achievement of each of these proposals are analyzed. Our analysis shows that the NSFC plays an important role in promoting Chinese human geography to engage in innovative basic study and to serve national strategic development. The NSFC contributed substantially to the interdisciplinary research, the application of new methods, the growth of new research topics and the construction and expansion of research teams in the development of Chinese human geography. This paper also reports the main progress of Chinese human geography over the past three decades, revealing some important characteristics and development tendency of this discipline. In conclusion, we call for developing a locally grounded and globally influential Chinese human geography through concerted efforts of researcher community and NSFC as a research foundation.