基于列车时刻表数据,以地级城市为研究对象,通过提取两两中心城市间的最短交通时间,以平均可达性为度量指标,测算了全国31个中心城市的可达性水平,分析了高铁对中心城市可达性格局的影响。依据中心城市到全国地级城市的最短交通时间提取全国31个中心城市的一日交流圈范围,分析了中心城市的高铁效应,并选择北京、上海、广州、武汉、重庆5个中心城市作为典型案例,分析和探讨一日交流圈空间格局变化的影响因素。结果表明：① 中心城市可达性水平与城市的空间区位及城市的对外交通条件关联密切;② 高铁网络的发展使中心城市的可达性水平有所提升,受城市所处的空间区位及高铁建设条件的影响,不同城市的可达性改善程度存在差距;③ 高铁对中心城市一日交流圈范围拓展的影响显著且呈东中西差异分布,中心城市一日交流圈覆盖的地级市数量增加,在城市密集地区,地级市被叠加覆盖的次数增长;④ 中心城市一日交流圈的拓展与高铁线路布局走向一致,优越的中心地理位置有利于中心城市交流圈范围的扩大,地形、水域等地理障碍则会限制城市交流圈在不同方向上的拓展;⑤ 高铁网络的发展对改善城市可达性的作用正逐渐赶超城市空间区位对城市可达性水平的影响。
Railway is an important way of transportation to combine Chinese cities, and its upgrading plays an important role in improving spatial pattern of cities′ accessibility. Having selected prefecture-level cities as study objects and extracted the shortest-time distances between every two central cites based on data from train schedule, the article calculated the accessibility of 31 central cities by employing the indicator of average accessibility, and analyzed the impact of high-speed railway on central cities′ accessibility. Then the daily communication areas of 31 central cities are abstrcted and the effects of high-speed railway is explored. What′s more, five cities were selected—Beijing, Shanghai, Guangzhou, Wuhan and Chongqing as typical cases to analyze factors which influenced their spatial patterns of daily communication areas. Results are shown as follows. 1) The accessibility of central city is closely related to spatial location and external traffic condition of the city. 2) High-speed railway network has promoted the accessibility of all central cities, but different city has different improved degree of accessibility under the influence of city′s spatial location and construction condition of high-speed railway. 3) The impact of high-speed railway on expanding daily communication areas of Chinese cities is significant and it distributes in the east, middle and west zones. Meanwhile, the number of prefecture-level cities covered by daily communication areas is increasing, and these cities are covered by more central cities′daily communication areas in urban populated areas. 4) The expansion of central city′s daily communication area is in step with the layout of high-speed railway. Besides, the superior geographic position will be beneficial to the expansion of central city′s daily communication area, but terrain and water and other geographical barriers will limit its expansion on different direction. 5) The impact of high-speed railway is gradually catching up and will surpass the impact of city′s spatial location on improving cities′ accessibility.
Using a database of Chinese outward foreign direct investment (OFDI) to Africa from 2007 to 2011, and economic, population and energy data of 43 African countries, this article analyses the spatial distribution of Chinese OFDI to African countries and its determinants. By adopting a factor analysis, five main factors are obtained from sixteen indexes. A linear regression model is used to examine the influence of these five main factors towards the Chinese OFDI to African countries. In the model, Chinese OFDI per capital is taken as an independent variable, and the five main factors as dependent variables. The results showed that the infrastructure, urbanization and marktization of the host countries are significantly correlated with the spatial distribution of Chinese OFDI to African countries, while energy and size of market are insignificant enough. The result strongly opposes the argument that the purpose of Chinese OFDI to African countries are mainly for resource access. Furthermore, the results of the analysis also shows that Chinese OFDI to African countries are weakly correlated in space whilst of no insignificant spillover effect to its neighboring countries. The related background reasons are also provided in the article. Based on the above analysis, the article put forward suggestions for the policy makers in terms of the development of Chinese OFDI to Africa.
Emerging at the end of 1980s, urban theorists, cultural critics and social commentators have devoted a tremendous amount of attention to the study of Los Angeles. This attention derives from the complex theoretical and practical urban issues in Los Angeles, and also from the continuous competition among the power of globalization, which obviously influenced the general economic order all over the world. Los Angeles School (LA School) is constructed by a group of geography scholars, such as Edward W. Soja, Allen J. Scott, Michael J. Dear, Mike Davis et al., to generalize their systematic academic points of view. This article aims to make a detailed and systematic introduction to the LA school, and tries to sort out its impacts on many disciplines in the field of human geography. According to the summarization, this article supports that the LA school is based on Soja’s social-spatial dialectics theory. This theory strongly suggests that spatiality also plays a big role in the formation of social relations when the basic production mode in the era and keeps unchanged. Under this theoretical framework, we can see that crisis and reconstruction are just the dialectic’s projection in reality, which means that crisis tends to cause urban reconstruction, and the reconstruction may lead to some new urban crisis at the same time. Los Angeles metropolitan area has provided a vivid interpretation and reasonably exemplified LA school’s basic academic points of view, as well gives us an accurate demonstration of the circulation between urban crisis and reconstruction. Many views of LA School have already made an important influence on the branches of human geography, such as economic geography, urban geography and social geography, providing a lot of important academic hypothesis and ideas for follow-up researches. The main contribution that the LA school has made includes the significant enrichment on the core and traditional idea of the relationship between mankind and nature, as well as the promotion of the new industrial space concept in the field of economic geography. Meanwhile, the case of Los Angeles metropolitan’s typical polycentric spatial structure may be the representative of cities and city-regions in the future, which has already led to much more researches concerning about the description and definition of urban spatial structure, as well as the emergence of some new conceptions such as sub-centers and edge cities. As to social issues LA school regards them as results of social and spatiality relationship, for example, economic restructuring has increased employment but also increased poverty and social polarization, so that LA school strongly stands for the concept of spatial justice, which means no matter which columns or groups the citizens belong to, they should be given equal rights to live, work and enjoy the entertainment in the city. However, the LA school also bears some critical voices and doubts, such as some doubts about its basic epistemologies, which cannot be proved and certificated by regular methods, we have to accept that the LA school still has significant and positive influence in promoting the crucial disciplines in human geography.
The research on spatial differentiation of human settlements environment suitability in typical tourist cities plays an important role in exploiting local human settlement environment resources. Meanwhile, it provides scientific basis for the sustainable development of local tourism. This article applies the fuzzy analytic hierarchy process (Fuzzy AHP) to choose 30 typical tourism cities in China as the research object from 101cities who have five 3A or more scenic spots. By establishing human settlement environment suitability index system and using entropy method, this article obtains the economic environment suitability, ecological suitability, suitable climate and environment, service environment suitability and human settlement suitability comprehensive score for 30 typical tourist cities. Results show that Beijing and Shanghai obtain the top two score in the human settlement suitability and have absolute advantage than others; the Yangtze River Delta region (Suzhou, Wuxi, Hangzhou etc.) has a little difference between the ranking of human settlement suitability and typical tourist city and most of them are in the top 15. Moreover, they do well in the coordinated development of human settlements environment and tourism resources. While the coastal city, such as, Dalian, Qingdao and Xiamen, has a low ranking of the typical tourist city, the score of human settlement suitability is high; The cultural landscape tourism city, such as Xi'an and Luoyang, acquires a low ranking of the human settlement environment suitability. Although Chongqing and Guangzhou have advantage in typical tourist cities, the score of human settlement suitability are lower; accordingly, they should pay more attention on improving ecological environment and service environment.
Urban metabolic systems are co-evolution systems of the urban economic development, the natural environment and the social environment. In this article, 31 Chinese cities′ metabolic efficiencies are tested by the material flow analysis, data envelopment analysis (DEA) and Malmquist index. Inputs and outputs of urban metabolic systems in 2000, 2010 are measured in the DEA and Malmquist index, such as economic output, environmental undesirable output, water, electricity, fossil fuels, metallic minerals, building materials, food and other inputs. Chinese cities metabolic systems have relatively high overall efficiencies, especially cities in the Eastern Coastal and Central China, with higher pure technical efficiencies and scale efficiencies than the western cities. In 2000, Tianjin, Haikou and other six cities reached the DEA optimal; while in 2010, seven cities reached the DEA optimal. The overall metabolic efficiencies of such highly developed cities as Beijing, Shanghai, Nanjing, Suzhou and other cities have maintained a relatively high level, with the average reaching more than 0.5. While the least efficient cities, Fuzhou, Chongqing and et al., have not improved significantly during the last decade. Large cities have better performances in urban efficiencies than that in giant, large and extra large cities. Since 2000 to 2010, the overall urban metabolic efficiencies, pure technical efficiencies and all other efficiency indicators show a decreasing trend, except the overall efficiencies and pure technical efficiencies of cities in the Western and Central China. It is important to take the strategy of resource-conservation and environmental protection to enhance the metabolic efficiencies of Chinese cities. Moreover, the overall urban metabolic efficiencies in large and extra-large cities are better than that in mega-cities, which proves that the moderate expansions of cities should be encouraged and supported in order to highlight scale economies; on the other hand, the government should control the scale of mega-cities to avoid diseconomies of scale. In addition, Most of the cities’ high scale efficiencies are the main reason for the urban better overall efficiency, which reflects the increasing returns to scale in urban metabolic efficiencies.
Appropriate management measures are required for the areas involved in climate protection. According to these requirements, the Regional Carbon Emissions Requirements Analysis System (RCERAS) was developed to provide data support and policy analysis for the implementation of regional carbon emission reduction policies. This article briefly shows the economic dynamics model of the regional demand for carbon emissions, as well as the development and design of the GIS-based RCERAS. With RCERAS, future carbon emissions demand of China's provinces and autonomous regions can be calculated easily. The results of energy carbon emissions can be queried, stored and displayed. With the help of GIS, the users can get the pictures of different regions and compare them directly, as well as export the image. In this article the carbon emissions of Jiangsu Province and Shandong Province are compared. Shandong’s carbon emissions are much higher than Jiangsu’s carbon emissions both from the point of the amounts and per capita. Different scenario analysis are made to provide decision support to local governments to implement carbon emission reduction measures, including energy structure regulation, industry structure adjustment and the mix of both. In this article, Tianjin is taken as an example, the result shows the effects of different reduction measures. International-oriented multi-regional synthesis of carbon emissions demand can also be calculated by implementing the system, which can provide more information and strive for more initiative for our government to participate in the climate negotiations. In the study, we take high developing countries as a whole and estimate their future energy consumptions and CO2 emissions. The results show that peak year of their energy consumption and carbon emissions would be in 2029.
以长江三角洲地区为例,构建城镇化效率的指标体系,运用DEA模型测度1990~2011年研究区城镇化效率;基于ESDA空间分析平台,运用全局、局部自相关测度模型对长江三角洲地区城镇化效率空间关联格局特征进行了分析。结果表明：① 从城镇化效率测度来看,自20世纪90年代起长江三角洲地区城镇化综合效率整体上偏低,呈上升趋势,技术效率上总体较高呈略升趋势,而规模效率总体偏高呈减弱态势;② 从全局空间关联来看,长江三角洲地区城镇化效率呈现出正的空间相关性特征,存在着效率空间集聚现象,即城镇化效率高（低）的地区空间相互邻接;③ 从局部空间关联来看,效率L-L关联区及H-H关联区所占比重较大,并呈现出不断上升的趋势;同时L-L关联区主要集中在台州、舟山等地,空间分布格局保持稳定;而H-H关联区主要分布在苏锡沪,并呈现出向绍、杭地区演化态势。
This article took the Changjiang River Delta as an example, built up index system of urbanization efficiency and measured the urbanization efficiency in the Changjiang River Delta from 1990 to 2011 using the DEA model. Based on the analysis of ESDA spatial platform, by using spatial metric model such as spatial correlation index and Local Moran,s I, the article analyzed the spatial correlation pattern of urbanization efficiency in the Changjiang River Delta. The results showed that: 1) Since the 1990s, the urbanization efficiency was overall low but on the rising trend, urbanization pure technical efficiency was entirety higher and on the rise, but urbanization scale efficiency was on the high and weakened as a whole. 2) Urbanization efficiency has a positive correlation characteristics, there existed a spatial cluster feature,it meant that the regions with high urbanization efficiency were apt to be adjacent to the regions with high urbanization efficiency, and the regions with low urbanization efficiency intensity were apt to be adjacent to the regions with low urbanization efficiency. 3) The regions with L-L or H-H correlation pattern had a large percentage since 1990s,and the number of regions were steadily increasing,which reflected the fact that the urbanization efficiency special cluster become more and more obvious. The L-L correlation pattern regions were mainly located in Zhoushan and Taizhou, where the spatial distribution pattern was stable. And the H-H correlation pattern regions were mainly distributed in Suzhou-Wuxi-Shanghai. After 2004, the H-H correlation regions have been increased, converged to Hangzhou and Shaoxing.
Tourists' willingness to pay for the tourist areas' admission is closely related to the development of the tourist areas and the tourists' travel experience. This study, a case study of Xixi National Wetland Park in Hangzhou, examines the tourists' willingness to pay for the tourist areas' admission. The willing to pay for admission is decomposed into three hierarchical indicators, which are the lowest, the best and the highest ones. Factorial analysis and regression analysis are conducted to investigate the factors influencing tourists' willingness. It is shown that the current admission fee is reasonable, which constrains the tourists’ highest willingness to pay. Meanwhile, the best admission and the lowest admission are way lower than the current admission fee. The characteristics of the admission fee, resort image recognition, facilities, value, travel motivation all influence the willingness to pay for the admission. Of all the factors, the characteristics of the admission fee and the image recognition contribute more to the willingness to pay than the other factors.
水足迹真实反映了一个地区人类生活消费对水资源的占用情况,正确利用旅游地水资源是促进旅游地可持续发展的重要前提。基于G?ssling旅游地水足迹概念模型,立足实体水和虚拟水相结合的视角,从旅游地住宿、餐饮、交通、娱乐、生态5个要素构建了旅游地水足迹测度模型,并对黄山风景区进行实证分析。结果表明：① 2002~2012年间,黄山风景区旅游地水足迹总量由551.15×104m3增加到909.40×104m3,水资源占用呈不断上升趋势。② 餐饮、交通、住宿、生态子足迹在水足迹总量中所占比重分别约为59.86%、25.75%、12.07%、2.32%,水足迹总量变化趋势与餐饮水足迹变化趋势大体一致。③ 虚拟水是景区水足迹总量的主要构成部分,年均约占总量的85.47%,以餐饮、交通为主;实体水年均约占14.53%,以住宿、生态为主。④ 水资源压力总指数由2002年的0.62增加到2012年的1.02,实体水压力指数由0.53上升到0.87,旅游人数不断增长是黄山风景区水资源压力逐年增大的直接原因。
Water footprint can reflect the occupancy of water resources in human consumption at a region. The sustainable utilization of tourism water resources is an important precondition to insure tourism sustainable development. Based on the theory and method of water footprint concept model proposed by G?ssling, the article built the water footprint measure model of tourism destination. The measure model contains tourist accommodation, catering, transport, entertainment and ecological water footprint with the perspective of the combination of real and virtual water. Taking Huangshan scenic area as an example, the authors calculated and analysed the tourism water footprint. The results show that: 1) During the period of 2002-2012, the total water footprint of Huangshan scenic area increased from 551.15×104m3 to 909.40×104m3, which is showing a tendency of rising in the occupancy of water resources. 2) Catering, transport, accommodation, ecological water footprint accounted for 59.86%, 25.75%, 12.07% and 2.32% of total water footprint respectively, which reflect the change trend of the catering water footprint roughly in line with the change trend of total water footprint. 3) The virtual water is the main constitute part of scenic water footprint, mainly catering and transport water footprint, an average of about 85.47% of the total. Accommodation and ecological water footprint consist mostly in real water footprint, an average of about 14.53% of the total. 4) The water resources pressure index of Huangshan scenic area increased from 0.62 in 2002 to 1.02 in 2012, real water footprint pressure index from 0.53 in 2002 to 0.87. Tourist numbers growth is the direct cause of scenic water resources pressure increasing year by year.
石油城市是人地相互作用十分强烈的人地系统,具有典型的脆弱性特征。在对典型石油城市大庆市经济系统脆弱性定性分析的基础上,构建经济系统脆弱性评价指标体系和评估模型,运用综合评价法、灰色关联度分析法及BP神经网络模型对大庆市经济系统脆弱性程度进行评估,并在此基础上预测2014~2023年大庆市经济系统脆弱性演化趋势。结果表明：① 17 a间大庆市经济系统的脆弱性程度整体上呈现波动下降态势,脆弱性指数由1996年的0.686降至2012年的0.283,目前已处在较低脆弱水平。2012年大庆市经济系统脆弱性仅低于克拉玛依市,高于其他石油城市。② 经济系统脆弱性主要影响因素为刚性产业结构和不合理的投资结构。③ 预测未来10 a,大庆市经济系统脆弱性先升后降,整体呈现下降趋势。依据大庆市经济系统脆弱性特征及影响因素,结合脆弱性演变规律,提出大庆市经济系统脆弱性的规避、拮抗、适应等调控途径。
Petroleum city, as a special kind of human-land system with intense interactions between human activities and natural environment, has typical vulnerability characteristics. Based on the qualitative analysis for economic system vulnerability (ESV) of Daqing City, the article establishes indicators system and assessment model .Then the comprehensive index method , grey relational grade analysis and BP neural network model are used to assess the ESV. The article also predicts the evolution trend of ESV from 2014 to 2023. The results indicated that the ESV of Daqing City had shown a declining trend from 1996 to 2012 and in a relatively low level at present, with the vulnerability index dropping from 0.686 (1996) to 0.283 (2012) and sensitivity index increasing from 0.142 (1996) to 0.280 (2012). Compared with other petroleum cities ,the ESV of Daqing in 2012 was just lower than Karamay, while higher than other petroleum cities. The dominant factor of ESV is responsive ability. Grey relational grade analysis was used to further explore the degree of influence of each index on the development level of the ESV. The results showed that the ESV of Daqing was seriously affected by rigid industry structure and unreasonable investment structure. BP neural network model was used to predict the ESV on the basis of present situation. The results showed that the ESV of Daqing City will increase first and then decrease in the future ten years. According to the characteristics and causes, combining the evolution rules of ESV, this paper puts forward the evadable, antagonistic and adaptable control approaches.The evadable approache is that Daqing City should grasp the life cycle of the petroleum industry and accurately grasp the economic transition opportunity.The antagonistic approache is to extend the industrial chain and develop the petrochemical industry.The adaptable approache is to improve the new industries and urban economic function.These control approaches can provide theoretical basis for reducing the ESV of Daqing, and then achieve its economic transformation and sustainable development.
山区人口承载能力评价是山区国土空间管理的基础之一,而准确的人口密度数据是正确评价人口承载能力的基础。传统的人口密度算法并未考虑地形起伏度对人口分布带来的影响,不能客观反映山区人口聚集程度。引入地形起伏度、海拔高度因子,选择岷江上游作为研究区,首先运用GIS技术提取地形起伏度,再运用SPSS软件对人口密度与地形起伏度相关性进行分析,确定县域不同地形起伏度与海拔人居适宜标准,剔除阈值以外不适宜人口聚居的面积,对人口密度进行修正。研究结果表明：① 岷江上游人口分布受地形起伏度的影响显著,二者的对数曲线拟合度为0.89,汶川县、茂县、理县、黑水县与松潘县地形起伏度与人口分布的相关性分别为：0.841、0.773、0.643、0.696和0.730;② 应用地形起伏度对岷江上游人口密度修正,为真实反映山区人口密度提供了新的考量依据,剔除了人口密度空间噪音,5县地形起伏度与海拔适宜标准分别为：汶川3.2°和3 693 m,茂县4°和4 033 m,理县4.3°和3 790 m,黑水4.4°和3 853 m、松潘4.2°和3 966 m;地形起伏度高值区面积越大,修正前后的人口密度偏差越大,地形起伏度较大的理县和黑水县修正后的人口密度分别提高了7.8倍和5.6倍;地形起伏度较低的汶川县与茂县修正后人口密度仅分别提高2.3倍与2.4倍;③ 岷江上游人口潜在压力大,不同区域应因地制宜,汶川和茂县采取重点集约发展战略,理县和黑水县采取适度开发战略,松潘县应采取恢复与保护生态策略。
A prerequisite for the protection and governance of mountainous areas is the scientific evaluation of the population carrying capacity, which depends on an accurate assessment of population density. The prior method of calculating population density does not consider the effect of the relief degree of land surface (RDLS) on population distribution. Therefore, it cannot accurately reflect the degree of population aggregation, especially in mountainous areas. Thus, this study selects the Upper Minjiang River Basin as the research area and introduces the RDLS and elevation factor. First, it extracts the exact population value by means of geographic information system technology. Second, it conducts the correlation analysis between the population distribution and the RDLS by using the Statistical Package for Social Science (SPSS). Then, based on the correlation and the population distribution analysis, this method is used to determine the appropriate standard of RDLS and elevation in different mountainous areas. According to the corresponding results, it calculates and corrects the population density of the upper Minjiang River Basin. The results show that: 1) The population distribution of the upper Minjiang River Basin is strong affected by RDLS, correspondingly, the R2 value between the RDLS and the population of the upper Minjiang River Basin is 0.89. The correlation coefficients between the RDLS and the population density of different county (Wenchuan county, Mao county, Li county, Heishui county and Songpancounty) are 0.841, 0.773, 0.643, 0.696 and 0.730, respectively. 2) The RDLS and elevation are introduced to revise the population density in the upper Minjiang River Basin. According to the results of the population cumulative distribution curve, the rational RDLS for human habitation in Wenchuan County, Mao County, Li County, Heishui County and Songpan County are 3.2°, 4°, 4.3°, 4.4° and 4.2°, respectively. The corresponding elevation is 3 693 m, 4 033 m, 3 790 m, 3 853 m and 3 966 m. 3) The population density has been corrected is clearly different from the previous result. The higher RDLS of mountainous areas, the more obvious discrepancy exists. For example, compared with previous result, the revised population density in Li County and Heishui County increase by 7.8 and 5.6 times, respectively. In contrast, the revised population density in Wenchuan county and Mao county increase by 2.3 and 2.4 times, respectively. 4) The upper Minjiang River Basin is confronted with greater pressure of population growth. Thus the population distribution of this area should be guided by local social, economic, topographic and other conditions. Specifically, Wenchuan county and Mao county should adopt intensive development strategy, Li County and Heishui County should adopt moderate development strategy and Songpan County should adopt ecology repair strategy.
Due to rapid urbanization, most cities in the world like Shanghai have a large number of underground facilities including public transport and commercial facilities such as subway, parks, shopping malls, etc. With the continuous development of underground spaces, the threat of rainstorm waterlogging is increasing. One of the significant components of impacts from rainstorm waterlogging is possibility of damage to underground facilities. Under the background of dramatic increase of extreme weather events, the safety issues of underground spaces against rainstorm waterlogging have become an important aspect of urban safety. The present study focused on subway in Shanghai central urban area, and analyzed the exposure of rainstorm waterlogging on subway based on multiple scenario perspective. Considering a series of impact factors of rainstorm waterlogging in urban area, the present study established a framework for exposure analysis of rainstorm waterlogging on subway through the combination of hydrological modeling and concept model for rainstorm waterlogging affected frequency. The results show that the exposure of subway in Shanghai central urban area was not very high. The total number of subway station exits which might suffer rainstorm waterlogging was only 40. Meanwhile, the number of inundated subway exits presents a remarkable increasing trend as increasing rainstorm intensity. Shanghai West Railway Station exit 1 and Loushanguan Road Station exit 3 have high exposure rank. The number of subway station exits with medium exposure was 18. There were 20 subway station exits, which have low exposure rank. The exposure index (ES) value indicates that there are obvious differences of exposure degree between different subway lines. Overall, Subway line 2 and line 11 belong to high exposure subway line; line 8 and line 10 have medium exposure rank; and line 1, line 4, line 7 and line 9 show low waterlogging exposure. These results will provide reference for the local government to improve waterlogging risk management.
利用珠江流域38个站点54 a日降水资料,采用Kendall非参数检验法、线性回归及空间克里格插值,对多种降雨指数时空变化及影响进行了研究。结果表明：① 珠江流域西部年降雨有减少趋势,流域大部分的降雨日数则有增加趋势;② 流域降雨具有季度、月份集中性,其中,季度集中性趋于空间均匀化,月份集中性趋向空间极端化;③ 极端降雨阈值东高西低,全区极端降雨在20世纪60、80年代末有突变现象,P0.01%设计值在21世纪达到最高。综合多尺度降雨时空变化结果进行分析,将珠江流域划分为广东（包括江西）、广西中北部（包括湖南）、广西西南及云贵4个降雨特征区,广东尤其是珠三角地区及广西中北部地区应注重防洪安全,广西西南与云贵地区应注重保障用水安全。
Basing on daily precipitation data from 1959-2012 in 38 gauging stations in Zhujiang River Basin (PRB), we have adopted Kendall test and linear regression method in studying the spatio-temporal characteristics of multiple precipitation indexes as studied time series, conclusions are drawn as follows: 1) In PRB, annual precipitation decreases towards west and declines along time; RRB drops from center to surroundings and keeps an increasing trend in most part of the basin; 2) Precipitation is seasonal and moderately concentrated in June; PCI becomeseven in the whole basin while differences between FI6 values expands; 3) Threshold value of extreme rainfall descends from east to the west and jumps are found in 1960s and 1980s; volume of extreme rainfall with same recurrence interval comes to its peak in 21st century; 4) Four precipitation regions are divided as (a)Guangdong District, (b) north-central part of Guangxi District, (c) south-west of Guangxi District and (d) Yunnan-Guizhou District; flood prevention is crucial for aand b districts especially Pearl River Delta region, and water safety is major concern for c and d District.
The impact of rainfall variation on watershed hydrological process is an issue of great deliberation in geographical and environmental sciences. In this article, a comprehensive watershed model—The hydrological simulation program FORTRAN(HSPF) was set up and calibrated for the Dongjiang River basin in China, and was repeatedly run with various rainfall scenarios generated by the daily rainfall stochastic simulation model. The results indicated that: (1) The runoff changed in the same trend either with rise and fall in mean value or variation coefficient of rainfall; (2) In the four given scenarios (mean value of rainfall has increased by 20% and 40%, decreased by 20% and 40%, respectively), change magnitude of runoff was similar under same change magnitude of mean value of rainfall; (3) The average annual runoff raised by 24.93% when the variation coefficient of rainfall raised by 40%, and raised by 10.84% when the variation coefficient of rainfall raised by 20%. However, it fell by 3.84% and 5.35% respectively when the variation coefficient of rainfall fell by 20% and 40%, which presented that the increase of variation coefficient of rainfall has a greater impact on runoff than the decrease of variation coefficient of rainfall does. The intensity of rainfall change is an important factor affecting the runoff, and heavy rainfall has a great effect on the runoff; (4) Change of runoff due to fluctuation of variation coefficient of rainfall gradually decreased, when variation coefficient of rainfall gradually declined; (5) Average annual runoff raised by 33.99% as mean value of rainfall raised by 20%, and raised by 10.84% as variation coefficient of rainfall raised by 20%, which means change of mean value of rainfall has bigger impact on runoff change than variation coefficient of rainfall; (6) Variation of monthly runoff caused by different rainfall scenarios is more obvious in June, July and August than other months.
分别于生长季（2004 年7 月）和非生长季（2005 年1 月）在苏北海岸带盐沼沿环境梯度采用静态箱技术原位测定二氯苯通量。结果表明：研究区大气中二氯苯可能源于海水外源输入,海岸带盐沼植物和土壤对外源输入的二氯苯具有重要的吸收作用,盐沼土壤和植物根系对二氯苯的自然吸收强度大于盐沼植物地上部分,其强度具有显著的物种依赖性;海岸带盐沼对外源输入的二氯苯的自然吸收能力具有显著的季节差异性,这种季节差异性源于高等植物及其根际环境自然吸收能力以及对生态因子响应敏感性程度的季节差异;海岸带盐沼对外源输入的二氯苯自然吸收能力具有显著地空间异质性,这种空间异质性与盐沼生态系统对二氯苯自然吸收能力的物种依赖性有直接的关系。因此,盐沼植物是大气二氯苯自然吸收库的重要组成部分,并对其时空变化特征具有重要的影响。盐沼生态系统高等植物物种种类、生物活性以及影响生物活性生态因子的空间差异性是盐沼对二氯苯的自然吸收强度空间分布差异性的重要因素, 即使在高等植物生物活性降低的非生长季,高等植物地上立枯的存在也能够对大气中二氯苯的自然吸收产生影响。
Dichlorobenzene (DCB) is used primarily as a chemical intermediate, or as solvent and has adverse effects on animals and humans. The fluxes of DCB were measured seasonally using static flux chambers along an elevational gradient of a coastal salt marsh of eastern China. Main results are as follows, DCB of the atmosphere may be from external input of seawater in the study area, the plant and the soil of coastal salt marsh ecosystem are important sink of DCB, natural removal flux of soil and plant roots is more than that of above ground biomassof plant, its strength has significant species dependent. Seasonal variation of natural absorption flux of DCB is significant, it is from the seasonal difference of natural absorption capacity from higher plants, their rhizosphere environment, and the sensitivity degree of response to ecological factors. Significant spatial heterogeneity of natural absorption capacity of DCB is significant, it were closely correlated with species dependence of absorptive capacity. Therefore, the plant is an important part of the natural removal of DCB in atmosphere, and has a significant influence on the temporal and spatial variation characteristics. The spatial difference of plant species, biological activity and ecological factors that infect on biological activity of plant in salt marsh ecosystem are important factors that impact on spatial heterogeneity of natural absorption capacity of DCB, the presence of standing litter of the plant could also have an impact on natural absorption of DCB of atmosphere, even in no growth season that biological activity of plant is lower.
In this study, the variation and relationship of stable water isotope both in precipitation and atmospheric water vapor, the influence of different moisture sources and their strength during transportation on precipitation isotopes are analyzed by using precipitation events isotope that covered a period of Jan. 2010 to Dec. 2012 in Changsha and TES retrievals of daily HDO, H2O data from Mar. 2010 to Dec.2011. The results show that firstly, decreasing atmospheric water vapor isotope values ??with increasing altitude. Secondly, comparing atmospheric water vapor with precipitation, the former is more depleted in isotope. Thirdly, precipitation isotopes values are high in winter and spring, low in summer and fall, referring to water vapor isotope, it is high in spring and summer, low in fall and winter. Fourthly, isotopes both in water vapor and precipitation have evident fluctuation. Moisture trajectories of precipitation events for summer and winter in Changsha suggest that in summer, the moisture is transported by the southwest and southeast monsoon from low latitude oceans, with high humidity, low stable isotopic ratios owing to the rainout of water vapor along the transport history. Then, in winter, the water vapor is primarily from the westerly transportation, with low humidity, high stable isotopic ratios in precipitation. Further analysis of the relationship between moisture flux and precipitation isotopes in summer Changsha confirmed that the circulation effect is credible.
利用国家气象信息中心气温数据集1961~2011年中国东北地区资料及NCEP /NCAR再分析资料,对东亚冬季风与东北冬季气温变化特征的对比分析表明：从20世纪90年代起,东北冬季异常冷、暖事件明显增多,冬季风异常强、弱事件也相对增多;1986年前后东北冬季气温发生增暖性气候突变,冬季风同时进入转弱阶段;冬季风在2004年进入偏强阶段,东北冬季气温在2009~2011年出现转入低温阶段迹象。冬季风通过影响200 hPa 东亚急流,500 hPa东亚大槽、乌拉尔高压,850 hPa风场,地面西伯利亚高压等的异常导致东北冬季气温的年际和年代际异常。
The contrastive analysis of the winter monsoon intensity index and the winter air temperature in Northeast China during 1961-2011 is made by using the temperature dataset from National Meteorological Information Center of CMA and the data of the NCEP/NCAR reanalysis. The result shows that abnormal cold and warm events increased obviously in Northeast China since the 1990’s, and the strong and weak EAWM abnormal events were relatively increased. A warming climate jump of the winter air temperature occurred in Northeast China in 1986. EAWM has turned to continuous weaker at the same time. EAWM entered the stronger stage in 2004. The winter air temperature in Northeast China appeared the emergence of signs in 2009-2011 years which was into the low temperature stage. EAWM influenced the abnormal of some systems such as the East Asian westerly jet stream at 200 hPa, East Asia trough and the high in Ural at 500 hPa, wind at 850 hPa, Siberian high on the ground to lead to the interannual and interdecadal abnormal of the winter air temperature in Northeast China.