With the development of knowledge economy, Chinese industrialization is transferring from traditional factor-driving stage to innovation-driving stage. Innovation becomes a significant force for promoting urban industrial efficiency. Exploring the spatial pattern of Chinese urban industrial innovation efficiency can make contribution to improving total innovation efficiency and industrial upgrading for China. 288 cities at prefecture level and above in China are chosen as the objects of study, in order to investigate on the spatial pattern of urban industrial innovation efficiency as well as seek its influential factor. To begin with, we use industrial innovation data from national economic census, and establish an index system of urban industrial innovation efficiency, which is constructed from innovation inputs aspect and innovation outputs aspect. By using Data Envelopment Analysis (DEA), urban industrial innovation technical efficiency (TE) is explained separately from Pure Technical Efficiency (PTE) and Scale Efficiency (SE). Moreover, we divide 3 categories of urban industrial innovation efficiency cities through clustering analysis, exploring spatial pattern characteristic of them. Our findings are 1) Overall spatial pattern of Chinese urban industrial innovation efficiency shows gradient weakened from the east to the west, while the spatial characteristic for PTE and SE is mismatched. 2) Spatial distribution of industrial innovation efficiency cities is approximately coincided with Chinese population distribution, which relates to the “Heihe-Tengchong Line”, and displays obviously “core-periphery” spatial structure in regional scale, such as the Beijing-Tianjin-Hebei region, the Changjiang River Delta region, the Zhujiang River Delta region, the Bohai Rim region and the Chengdu-Chongqing region. 3) Industrial innovation capability and Industrial developing basement are developing combined impact on the spatial pattern of Chinese urban industrial innovation efficiency, while improving human capital elements and optimizing the scale of industrial innovation input is the key of urban industrial innovation efficiency.
In 2011, the proportion of China's urban population exceeded 50%. The focus of China's urbanization is shifting from improving the urbanization rate to optimizing spatial efficiency, and it is of significant importance to explore the optimal city size distribution in terms of economic performance. City size distribution is a kind of spatial structure that reflects individuals' location choice after weighing their own advantages and disadvantages, and this is bound to affect the performance of economy. However, there is no logical consistency answer on which one is more efficient, pursuing mono-centric spatial structure for higher agglomeration economy or hunting polycentric spatial structure for lower agglomeration diseconomy. Besides, research on the economic performance of city size distributions has long been neglected. Existing studies of urban size distribution are mainly concentrated in discovering the stylized facts and rules of city size distribution, validating whether the theory of city size distribution conforming to the facts, and explaining the mechanism on the formation of city size distribution and so on. Based on city-regions cross-sectional data in 2010, this article studies how different city size distribution influences economic performance, what kinds of city size distribution has a higher economic efficiency in the mono-centric or polycentric dimension, and whether the optimal economic performance of urban size distribution is affected by other factors. This conclusions show that: 1) the mono-centric city size distribution tends to be associated with higher labor productivity, but with further samples subdivision, the optimal city size distribution turns up a mono-poly-mono shift along with the rise of scale. 2) No evidence has been found to support that the level of economic development affects the optimal city size distribution. And 3) it is of great significance to shape the cities in China's western region into mono-centric form.
The domestic express market in China expands quickly since 2000. Air cargo transportation industry becomes a new growth point in China civil aviation transportation industry. In 2012, China civil aviation cargo turnover volume is 57.44×108 tn-km, second behind US in the world. China air transportation varies from both time and space with the international air freight transportation market change and domestic air freight transportation rise. Air freight transportation is a very important part of air transportation and flight network is its spatial carrier to provide air transport service. Illustration of China air transportation feature and its spatial pattern to both air freight transportation industry and aviation industry will contribute to formulate aviation industry development strategy, which has a very important theoretical significance and practical value to China air freight transportation industry development and airline network layout optimization. The air transportation and its spatial pattern are the important topics in air transport field in China. Currently concerning studies are mainly focusing on the passenger traffic. Thus, this paper analyzes the spatial pattern and temporal evolution of air cargo transportation in China based on SDE and Spatial Gini index. SDE is used to describe temporal process of the element spatial distribution. Spatial Gini index is used to measure element concentration in network. With domestic airport and flight segment data from 2001 to 2012, this paper calculates SDE and Spatial Gini index to describe China air cargo transportation and its spatial pattern. The result shows: 1) The spatial pattern of the air cargo transportation is consistent with the economic pattern, mainly concentrating in Shanghai and Hangzhou—the core of Changjiang River Delta, Guangzhou and Shenzhen—the core of Zhujiang River Delta, Beijing and Tianjin—the core of Beijing and Tianjin District, as well as developed areas in western China, (e.g.) Chengdu and Chongqing). China flight transport center is moving to the northwest inland region from the southeast coastal areas; 2) Four combination airports (e.g. Beijing/Tianjin, Shanghai/Hangzhou, Guangzhou/Shenzhen and Chengdu/Chongqing) replace Beijing, Shanghai and Guangzhou and become four highly concentrated regional air freight transport combination hubs. Air freight network is changing from coexistence hybrid network (point-to-point structure, hub-and-spoke hub structure) to hub-and-spoke network. 3) The air cargo at the airports and flight segments tends to disperse, and its volume on hub airports and main routes reduces slowly year on year. Regional airports and branch flight segments undertake more and more air cargo. 4) The air cargo transportation main corridors are established between four combination hubs. On those corridors, the total air cargo volume reduces from 47.04% in 2001 to 30.91% in 2012.
In order to explore the basic rules of cultural information flowing between rural and urban areas, the scientific questions which are how to simulate quantitatively the flowing state and how to construct the spatio-temporal integration model are to be answered based on the big-data thinking, Petri network theory, RS-GIS-GPS integration technology and the analysis tool of State flow. From the perspective of dynamic “field” of rural and urban cultures, the spatio-temporal integration of cultural information flow between urban and rural areas is our research object. While, the research is to explore the influences of culture information flow on the forming of rural-urban cultures in space, uncover its mechanism, construct spatio-temporal integration model, initially establish spatio-temporal integration theory of rural-urban cultural information flow, and strive to promote the integrative development of multidiscipline such as culture geography and information sociology and create new theory list, which is to establish the theoretical foundation for accelerating the development of urban-rural cultural integration, and to provide the scientific and theoretical basis for sustainable construction of CIRSP between rural and urban areas in China.
With the development of Chinese transition, multinational corporations (MNCs) of fortune 500 gradually expand in China functionally and spatially. The article intended to explore how MNCs functional locations evolves in China and the mechanism of their expansion using fortune 500 investment statistics during 1979-2012. The results show that, 1) MNCs have invested in China sequentially. Production institutions and office were set up in China first. Then headquarters, R&D and sales institutions were set up in China in subsequence. After the government published the provisions of foreign-funded joint-stock company on several issues in 1995 and China’s entry into WTO, foreign institutions entering in China have been grown quickly. 2) Spatially, different functions have different location preference. Headquarters and R&D institutions emphasize talent and information resources, and inclined to distribute in top cities such as Beijing and Shanghai. Production institutes tended to locate in low cost areas and distribute across different level cities. Sales and business service functions tended to locate in great market potential areas. 3) The article highlighted the trend of subsequent entering, function upgrading and gravity transformation of MNCs based on expanding pattern of Siemens in China. 4) The function distribution and evolution has much to do with urban hierarchy and regional economic environment. Headquarters and R&D functions agglomerate in first tier hierarchy cities, production and sales distribute broadly in regional center such as province capital and other cities. 5) The location gravity center of MNCs has experienced apparent transformation. In early period, headquarters and R&D facilities agglomerated in Beijing, while production and sales gravity center agglomerated in the southern China. With the change of regional development environment, the gravity of R&D institutes moved to south and the gravity of production and sales moved to north. All gravity centers of MNC function intended to agglomerate together. 6) The results showed that the transformation of regional economic pattern is the main cause of MNCs functional gravity evolution. At the beginning of opening reforms, the strategy of regional economic development gave priority to coastal areas. The main function of MNCs entered in China is production and sales, which were mainly located in the southern China. With the marketization and globalization gravity shifting to the northern China, the gravity of sales and production of MNCs were also shifting to north of China. The campaign of western development since 1999 induced production, business service, office and headquarters of MNCs shifting to west. The balancing of regional spatial pattern propelled MNCs function gravity agglomerate together. The vertical linkages of functions further have propelled the co-agglomeration of functions of MNCs.
This article applied artificial bee colony (ABC) algorithm to modelling the urban land use change. The principle of ABC algorithm is to discover the optimum nectar source by imitating bees’ behavior of gathering honey. Hence, ABC is a new kind of optimization algorithm same as genetic algorithm, neural network, which have been wildly implemented in the modelling of land use cover/change (LUCC). This study focus on the implementation at three aspects: 1) Land use transition rules: In order to analyzes the effects between land use dynamic and its driving forces, we defined the format of land use transition rules, which are composed of land use type, the fitness function, the cover percentage and the corresponding upper and lower values of each factor. Therefore these transition rules, which are obtained via automatic searching from samples, are able to demonstrate the relationship between land use dynamic and driving forces in the form of “IF…THEN”. 2) Fitness functions: In order to eliminate the distractions caused by imbalanced samples, we chose three different fitness functions to evaluate the classification results. These functions, including the G-mean function, the F-measure function and the Percentage of Correct Predicted (PCP), are well suit to various requirements such as sensitivity preferred rather than the overall accuracy. 3) Performance testing: two experimentations, which are based on UCI datasets and reality land use change of New Castle County between 1984 and 2002, were provided. The classification results were also compared with logistic regression, neural network, SVM and Ada-boost algorithms. According to the UCI datasets, the ABC which adopt the PCP as fitness function has acquired the best overall accuracy. They were 98.00% for Iris and 97.51% for Breast-Cancer-W. On contrary, from the results of New Castle County datasets, the ABC using G-mean instead of PCP as fitness function has obtain better results, which were 78.53% of overall accuracy and 0.569 3 of Kappa coefficient. These differences indicates that the G-mean function are more suitable for imbalanced samples. In addition, we also provided a discussion about the optimal parameter selection problem of ABC. In this article, when the number of bee was 100, the maximum of integration time was 500 and the limitation of unimproved-times was 50, the ABCs had achieved the best performance. In conclusion, the comparison of two cases shows that the overall accuracy and Kappa coefficient of ABC algorithms are comparable to the other algorithms. Hence, the ABC algorithm is appropriate for the modeling of urban land use change.
Multi-factor comprehensive evaluation is widely used to assess intensive land use, and positive and/or negative indicators are usually employed in the evaluations. In practice, moderate indicators are exiting, which have positive effects on intensive land use within a certain value range, and negative effects when exceed the range, such as urban comprehensive volume rate, building density and population density. Moderate indicators pose a challenge to traditional multi-factor comprehensive evaluation method because the traditional method to standardize the indicators is based on a linear relationship between the original indicator values and standardization results. In this article, we propose an improved indicator standardization method based on the law of diminishing returns. This method supposes the land user as a consumer, the indicator standardization value Fi as utility and the indicator value xi as consumption unit. Consequently, the contribution of moderate indicator to the assessment results of intensive land use follows the law of diminishing returns. The model to simulate the standardized values of moderate indicators should meet three criterion: when x≤x0,f(x)’≥0;when x≥x0, f(x)’≤0;f(x) is a second-order continuous and f(0)=0. Based on quadratic equation, we proposed a standardization formula: Fi=axi2+bxi. This formula meets the three criterion, and the parameters a and b can be calculated by indicator ideal value x0 and coordinate origin [0, 0]. Thereafter, a new multi-factor comprehensive model to evaluate intensive land use was built. This model combines the standardized moderate indicators derived from the improved method and the linear indicators calculated by the traditional method. Then, the population density of Chongqing was used to test and compare the improved and the traditional methods. The results show: 1) the population density of the metropolitan economic circle is greater than the ideal value 0.74×104/km2, and the weight of this indicator is 0.147 6. Moreover, the contribution score of population density in the intensive land use of this areas is 14.76. 2) The formula of the improved model is Fi=-1.826xi2+2.703xi. The improved method generated decreased value of the contribution of population density in the intensive land use of the metropolitan economic circle, compared to the traditional method. While, increased values were derived from the improved method in different degrees in other areas. 3) The evaluation results from the improved method are more objective and rational compared to the traditional method. Furthermore, the results from the improved method suggest policies more consistent with the population control strategy of the five functional districts of the Chongqing city. Although the quadratic multi-factor comprehensive evaluation model shows strength in standardizing population density of Chongqing, it needs further improvement and applications in other area.
As a kind of urban public facilities, parks are the main places for citizens’ amusement and relaxation. Only when citizens can conveniently access to parks, they can function well. Park accessibility is considered as the main factor that will influence citizens’ use of them. That is the reason why scholars have paid attention to studies on the accessibility to parks for recent decades. In the previous studies on the evaluation of accessibility to parks, the relevant measures mainly focused on the ratio of parks’ service area to the total area, while spatial distribution variation in citizens selection opportunities for parks use was somehow overlooked, which, to some extent, embodied relevant studies’ limitations in representation of spatial equity on parks’ spatial distribution. From the perspective of opportunities equity, reasonable park spatial distribution lies in: citizens possess the same selection chance for parks use when they pay the same cost to visit them. On the other hand, the relevant studies always ignored population distribution, or simply assumed that population was evenly distributed, which will finally influenced the evaluation results of accessibility to greens. Taking the ancient city and its neighbor region in Shaoxing City as the study area, residential building information were utilized to estimate the distribution of permanent resident population, then GIS network analysis tools were used to measure the service area of parks, the distribution of selection opportunities residents possessed for parks use was revealed, and park accessibility was obtained in the fine spatial scale from the perspective of spatial equity. The analysis results revealed that opportunities inequity exists in the service area of parks, which can be more accurately measured by incorporating the attraction index. Some relevant optimization strategies for park distribution were proposed such as improvement on spatial quality of parks, increase of community parks inside the ancient city, parks construction synchronized with urban development, reduction of spatial inequity by utilizing the price mechanism in parks’ densely distributed area. However in this study, attraction index was quite objective, and the capacity of park was neglected as well. Unique demands of specifically group such as the elder, kids or the disabled for parks were unfortunately not considered, which will somehow deviate the origin that public resources should be leant to the disadvantaged group. The further study should be conducted in the near future.
The purpose of this article is to study the influence of industrial structure on the economic inequalities among counties at the less developed Yunnan Province in China. In the process of modernization, the country economy is the basic element of national economy and the ties of city with rural economic. Nowadays, Chinese economic operation of the prominent contradictions such as the regional inequality mostly is reflected in regional scale at countries. Therefore, it is necessary to discuss the county economic difference in order to coordinate regional development. Yunnan as a frontier, ethnic, mountainous and poor district, it is located in the western inland and one of the most imbalanced areas with regional development in China. After studied the literatures, we found the academia has not discussed the country economy from the perspective of industrial structure in Yunnan Province. So this article takes the shift share analysis and Industry decomposition of the Gini coefficient methods, based on the data of statistical yearbook, to analyze the evolution of industrial structure effecting county economic difference in Yunnan Province. The results show that: the economic disparities of counties affected by the deviation of industrial structure and competition greatly, the eastern counties of the industrial structure have a significant advantage, but the relative competitive advantage is weak, the western and southern counties have more competitive advantage, but less structural disadvantages than the eastern counties. In recent years, the eastern counties are dominant in the industrial structure, competitiveness, and the difference between the western and southern county are widened; the results from the decomposition of the Gini coefficient of industry indicate that the secondary industry is the leading factor causing the county economy difference. In addition, the tertiary industry contributes to increase county economic difference and its impacts on county economic difference has become increasingly prominent; also the change of industrial Gini coefficient decomposition reveals that the industry concentration effects to expand the county economy divergence but the structure effect can reduce the economic disparity. Finally, some well-directed policy recommendations and measures are provided to coordinate the county economic development.
This article took the Changjiang River as an example to build up an index system of spatial efficiency and measured the spatial efficiency in the Changjiang River Delta in 1994-2013 and those of cities in Changjiang River Delta in 2005, 2009 and 2013 by using the DEA model. Based on the analysis of ESDA spatial platform and Local Moran's I, the article analyzed the spatial correlation pattern of spatial efficiency in the Changjiang River Delta. The efficiency of the Changjiang River Delta urban agglomeration and its spatial evolution process was in the "W" type characteristics and rose in volatility. Space efficiency of cities increased gradually while urban space differentiation was obvious, but the individual cities of urban agglomeration spatial efficiency gap was narrowing. Clustering characteristics showed the space efficiency and city scale, and the administrative level and location advantages have a certain correlation. Space efficiency is highly associated with the degree of distribution and factors of agglomeration. Too high or too low element agglomeration size will lower efficiency of urban agglomeration, and factors of agglomeration scale moderation will significantly promote the efficiency of agglomeration.
Place cognition developed in the human and environment interactions during land use change processes is increasingly valued by land use studies. Traditional place identity researches focus on qualitative methodology, results of which are seldom applied in land use management practices. This study is to build a framework to measure place identity in land use based on real land use environment background, in order to provide reference for land use social impact evaluation. Methods used include SoftGIS and case study. The dual meaning of place identity and its connection with land use are argued. Through integrating place identity theory with SoftGIS technique which is used to obtain the information of land users’ experience, knowledge, perception and valuation about environment, a framework for the platform to measure place identity in land use is designed. With confining the evaluation object as non-construction land, the platform is established by focusing on the core issue ‘which places are you most concerned about or are most attractive to you, and why?’ The platform includes four parts, namely user participation, project introduction, place marking and place evaluation. Online investigation is carried out through the Netherlands with the proposed SoftGIS platform. Data of 3 637 participants from six regions are obtained within two weeks. Participants are shown various maps on which they can mark their selected place with a pin. They are asked what makes that place special afterwards. With the online satellite map, regions of three different scales are shown. One is participant’s neighborhood, with a 2 kilometer radius centered on his or her home. Another indicates participant’s work activity region, with a 20 kilometer circle drawn around home. The third shows the Netherlands. 12 204 places are marked in the end. Based on the survey data, the study analyzes land use place identity difference among various social groups and explores the spatial difference with metrics. By modifying the Kernel Density Estimation method, a so-called Land Use Identity Index (LUI) is built to measure the intensity of land use place identity at a specific destination. With LUI, it is able to compare place identity between different land uses. An example of applying LUI in a land use planning project in Almere in the Netherlands is provided. Conclusions show that, compared with traditional methods, questionnaire design and investigation spatial scale with the platform are flexible. A fast data collection process can be witnessed. The platform encodes maps of high resolution satellite images, so that the field survey can make participants effectively recognize and locate the real land-use environment, and feedback real and accurate place identity information on land use. Case study indicates that it is feasible to integrate traditional quantitative GIS data and qualitative land use cognition data. The designed LUI can quantify spatial variance of place identity in land use. The result shows meaningful implication and may be applied to land use assessment or to decision-making in land-use planning projects.
Based on MAS-CA model improved by BDI decision model, using the land use data of 1998, 2003, 2008 and 2013, this article simulated the urban landscape pattern in 2020 an d 2030 of Jinshitan, Dalian ,which is the typical urban area of coast of the Yellow Sea. The Kappa coefficient is 0.635. The results show that:1) The BDI model supplement the deficiency of the MAS-CA model. After joining BDI decision, the MAS-CA model framework is further improved. Thus makes the results more accurate and specific. The precision reaches 89.1%. 2)The model simulation results show that the urban landscape adjoins to the coastline and the traffic line in Jinshitan area. The urban land moves closer to the coast line. Urban land concentrated in the central region of the area, and obviously expanded into the surrounding area. Land use transformations were most heavily happened in the village of Putaogou, Hejuzi, Miaoshang, Shizijie.3) There are many factors affecting land use conversion. The distance to the coastline is the leading factor of the trend of urban landscape pattern transformation in Jinshitan area. Because of the ecological environment of the coastal area is easily destroyed in the coastal area, the government should take measures to find the perfect balance point between environment protection and economic development.
Based on the theory of the Tourism Carbon Footprint, Tourism Eco-efficiency and Tourism Economic Effects, this article proposed the concept and model of Tourism Eco-efficiency. This study took Hainan Province as a research object, calculated the tourism eco-efficiency value of Hainan Province in 2012 quantitatively, and made a mechanism analysis on regional differences of tourism eco-efficiency. According to the empirical research, this article drew some conclusions as follows: 1) In term of the tourism eco-efficiency of Hainan Province in 2012, the tourism eco-efficiency of tourism transport was 0.898 yuan/kg, the tourism eco-efficiency of tourism accommodation is 7.13 yuan/kg, the tourism eco-efficiency of tourism activity or amusement was 16.32 yuan/kg, the total tourism eco-efficiency was 1.787 yuan/kg, the tourism eco-efficiency value of tourism activity and tourism accommodation is greater than tourism transport. 2) In case of the same travel distance, there were some measures to enhance the tourism eco-efficiency as follows: to improve the level of per capita consumption, to extend the average residence time, to increase the average frequency of participation of tourism activities, it is also known as an theory that tourism market structure with "short-distance, long stay, high consumption" is conducive for optimizing tourism eco-efficiency, vice versa, tourism market structure with "long-distance, short stay, lower consumption" will drives down the value of tourism eco-efficiency. 3) The reasons that the tourism eco-efficiency of Hainan Province is lower than some compared destination could be summarized as: longer tourists average outside transport distance, higher proportion of tourists choosing aircraft as transport model, tourism revenues by statistics relatively lower to the actual consumption figure.
Based on the method of econometrics, taking 9 prefectures and cities in Jilin Province as regional study unit, we analyze the tourism overall level, the spatial and temporal characteristics of tourism development in Jilin Province in 2002`2013. The results show that the status of tourism industry and its contribution to the economic development are increasing in Jilin Province. Although the relative difference of tourism development among the regions has narrowed down, the absolute difference is keeping expanding. The reason is that Jilin Province attaches great importance to the development of tourism and takes tourism as a strategic emerging industries and an important way to develop economy, transform development mode, optimize the industrial structureand improve the livelihood of the people. Therefore, tourism is rapidly developing for each region. However,because of the difference of tourism resources, traffic location, economic base and tourism economy, the absolute difference of tourism development in cities and counties is still widening, and spatial difference of tourism development is outstanding. The spatial agglomeration degree is high, but there is a tendency to develop in dispersed direction, the decline of space agglomeration degree can be attributed to the development of tourism industry in Yanbian, Baishan, Tonghua which is gradually weakening the layout of Changchun and Jilin as a single core circle. To realize the coordinated development of tourism, each region should suit one's measures to local conditions, and strive for the division of labor, the characteristics, the advantages, more benefits in whole tourism space layout. Based on the results of measurement and analysis, this article puts forward the spatial structure of "dual core, a group, four groups". Dual core refers to the "Changchun and Jilin" as the core; a group refers to the Central Industrial Tourism Group, consisting of Changchun, Jilin, Siping, Songyuan, Meihekou; four groups refer to the periphery of four major tourism groups: 1) western tourism group containing Baicheng-Song Yuan, 2) southwest tourism group containing Siping-Liaoyuan, 3) central and southern tourism group containing Tonghua-Baishan and 4) Yanji, Hunchun, Tumen River downstream tourism group. Finally, some suggestions are put forward: strengthening the radiation effect of the core area, making a clear regional tourism spatial location,highlighting the ethnic customs and the balanced development of regional tourism industry.
The evolution of tourism spatial structure was impacted profoundly by institutional elements in addition to resource endowments, levels of economic development, transportation and other factors. Based on the perspective of supply demand analysis, this article constructed the theoretical framework of tourism policy change and its spatial response, according to the path dependence theory and the interest groups theory of new institutional economics. We explored the path and motivation of tourism policy change to reveal the inner link between the tourism policy change and the development of the tourism spatial structure. And meanwhile, we took Anhui Province as an example, according to the different stages of the development of tourism industry, the change of tourism policy was divided into three periods: the formation period, the intensive period and the coordination and integration period, whose spatial response of the tourism industry was point pattern, single plate pattern and multi plate spatial pattern, respectively. We found that in the background of China's economic system transition, the tourism development was converted from the government-led to the market-led, tourism policies motivated the interest groups to invest tourism nodes, transportation facilities and so on, through its effect mechanism in different periods, and promoted the evolution of tourism spatial pattern from the point pattern to the plate pattern, the spatial response intensity of the tourism policy depended on the degree of government information and the degree of incentive of the policy to the interest groups.
Data collection was done on flood/drought-induced loss of agricultural products and also crop fields from 29 provinces(municipality) in period of 1961-2010. Change properties were analyzed using trend test method such as Mann-Kendall trend test in this study to investigate spatio-temporal distribution of flood/ drought hazards and related impacts on agricultural productivity over China. The results indicated that: 1) Flood hazards are significant increasing trends in middle, mid-west and northwest parts of China. Evident increase of drought hazards, however, is observed in northwest, northeast parts of China and also in the Yunnan Province. In China except north China and northeast China, flood hazards have enhancing impacts and no evident negative impacts from drought hazards can be identified; 2) Abrupt changes of flood-affected and flood-damaged crop areas in the northeast, north and middle China are found mainly during 1980s and during 1990s in the south and southwest China. The abrupt changes of drought-affected crop areas however are detected mainly in 1984 and those of drought-damaged crop areas in south and north China are mainly in 1977 and 1984 in the middle and east China; 3) Spatio-temporal alterations of flood/drought hazards result in evident increase of hazard-induced loss and loss rate. Conspicuous impacts of flood/drought hazard on agricultural productivity can be detected in west and north China; 4) Increased seasonal precipitation amount and also the intensifying precipitation extremes give rise to increasing intensity and frequency of flood/drought hazards in northwest, southwest and middle China. Decrease of seasonal precipitation amount results in higher frequency of droughts in northeast and north China. This study is of great significance in planning and management of agricultural activities under the influences of climate change across China.
The DGS1 segment in the Dishaogouwan section from the Salawusu River valley is a typical stratum to study the climate variations in the Holocene. Based on the dating ages and analysis of the grain-size features within the DGS1,we find that the particle gradually becomes finer but the sorting rate becomes poorer from mobile dune sands, peat, paleosols, semi-fixed sand dunes to the lacustrine facies and secondary loess; the grain-size parameter values of Mz(?), σ1(?), SK1 in the dune sands are lower than those in the lacustrine facies or secondary loess, and the KG value shows opposite trends; the Mz ranges from 2.26 to 3.36 (average 2.55) in the dune sands, 2.33 to 6.33 (average 4.28) in the lacustrine facies and 4.25 to 5.27 (average 4.58) in the secondary loess; the σ1(?) ranges from 0.51 to 2.51 (average 0.97) in the dune sands, 0.81 to 3.25 (average 2.13) in the lacustrine facies and 1.10 to 2.46 (average 1.46) in the secondary loess; the SK1 ranges from 0.01 to 0.45 (average 0.29) in the dune sands, 0.09 to 0.53 (average 0.32) in the lacustrine facies and 0.22 to 0.38 (average 0.36) in the secondary loess; the KG ranges from 0.92 to 1.70 (average 1.42) in the dune sands, 0.65 to 1.80 (average 1.13) in the lacustrine facies and 1.22 to 1.51 (average 1.44) in the secondary loess. They display distinct variations that correspond to the sedimentary changes. The surface microstructure of the quartz grains in the lacustrine facies under the electron microscope scanning shows typical aeolian characteristics with good roundness, without precipitated silica, but with pits on the surface. Together with the freshwater gastropod fossils discovered in the stratigrapgical layers, we suggest that the grain-size cycles in the DGS1 segment actually reflect the climate variations in the alternation of East Asian winter and summer monsoons in the Holocene, and the climate of the Holocene can be divided into four stages: the warming period of the Early Holocene; Holocene heyday; the fluctuation period from the Megathermal to cold; and the cooling period of instability and desertification. The climate changes in the DGS1 during the Holocene correspond well to those found in the North Atlantic and some places in China, which probably results from the global climate changes in the Holocene.
With the growing effect of global warming on the environment and socio-economic development, climate change research has become a hot topic and attracted broad attention from national government departments and the public. In its latest report for 2013, the IPCC has noted that the global mean surface temperature has increased by 0.85℃ (0.65-1.06℃), and the annual average temperature from 2003 to 2012 increased by 0.78℃ relative to 1850-1900, a period of nearly 130 years (in 1880-2012), indicating that rapid global warming is an indisputable fact. However, temperature changes are not limited to the earth surface, but are extending to the troposphere and the stratosphere which are important components of the Earth's climate system. Changes occurring at the surface, in the troposphere, and in the stratosphere are three main components of climate change. As an indispensable foundation for climate-change research, the determination on the change trend of upper-air temperature has quickly become one of the most important directions of climate-change research in recent years. In this study, based on the daily observed data from eight sounding stations in Xinjiang in 1980-2013, the change trends, abrupt change points, and their significance of upper-air temperature were analyzed using Mann-Kendall (MK) nonparametric test, and the relation between upper-air and surface temperature changes were also carried on a preliminary discussion. The results are indicated as follows: in last more than 30 years, patterns of statistically significant upper tropospheric and mid-lower stratospheric cooling and mid-lower tropospheric warming are clearly evident. The cooling rate in the upper troposphere and the mid-lower stratosphere was much more intensive than the warming rate in the mid-lower troposphere; Annual temperature cycle suggests that the peak temperature shifts from July in the troposphere to February in the mid-lower stratosphere, indicating the necessity of seasonal trend analysis. There were apparent seasonal differences in the upper-air temperature change, the cooling in the upper troposphere and mid-lower stratosphere in autumn and winter were larger than that in spring and summer, whereas the warming in the mid-lower troposphere was more pronounced during the spring and summer; Abrupt change points of upper-air temperature at three layers all occurred around the early 1990s, which were later than that of the hemisphere temperature, but earlier than that of the corresponding surface temperature; Surface temperature exhibited a significant correlation with mid-lower troposphere temperature, but a remarkable negative correlation with upper troposphere, the mid-lower stratosphere temperatures. Overall, the correlation between surface and mid-lower troposphere temperatures was the highest, followed by the mid-lower stratosphere and upper troposphere temperatures. Temperature changes of mid-lower troposphere and surface exhibited some differences in different periods and seasons, both of them presented warming trends during 1980-2013, while showed cooling trends during 1998-2013. Furthermore, the downward trend during 1998-2013 was more obvious in winter, which suggested that the winter cooling held a dominant position in the temperature descending of the mid-lower troposphere and surface in the last more than 10 years.
In recent years, seasonal droughts occurred frequently in Songhua River Basin. Serious meteorological drought led to many adverse effects on agricultural production and ecological environment. The analysis on the spatio-temporal evolution characteristics of meteorological drought can provide theoretical basis for countermeasures to reduce drought disaster. Based on observed meteorological data from 67 significant meteorological stations on the Songhua River Basin for the period from 1960 to 2009, the meteorological drought characteristics were studied using standardized precipitation index (SPI). Seasonal SPI during 50 years were determined in Songhua River Basin, based on which evolution characteristics and occurrence regularity of meteorological drought were analyzed in seasons. The variance of SPI in different seasons showed that the amplitude of drought variation in summer was maximum, which of autumn was the second. From the long-term view, the trend of spring drought decreased in Songhua River Basin, and the trend of summer drought and autumn drought increased, while basically no change in winter. During the period from 1960s to 1970s, spring drought and summer drought occurred frequently. In 1980s, drought situation was normal. However, after 1990s, summer drought and autumn drought increased obviously. Winter drought did not have great changes during the whole period. Influences of meteorological drought on basin irrigation were analyzed combined with GIS technology to provide a reasonable basis for combating drought. The results showed that meteorological drought of Songhua River Basin presented obvious spatial and seasonal zoning. By the view of geographical changing, regions influenced by drought mainly distributed in the northeastern and southwestern Songhua River Basin. By the view of seasonal changing, drought in spring and summer was the common types of drought. Summer drought was the most serious, and spring drought was the second. Spring drought was the most serious in the west of Jilin Province (eg. Baicheng City and Songyuan City). Summer drought was serious in the southeastern (eg. Mudanjiang City and Jilin City). The distribution of autumn drought was uniform in the studying area. Winter drought only occurred in partial region (eg. Baicheng City). When responding to drought, risk management model should be adopted to avoid the drought risk and close attention should be paid on meteorological drought monitoring.
River is the path of water current on the land surface that collection and transmission, and the hydrological response of a catchment and hydrological processes which represents the global changes of the response of the earth′s surface. It is of great importance to study the runoff evolvement process. Changing rules and the influence factors in the Yellow River and would enhance sustainable development of social economy and effectively protect our environment under the reasonable utilization of river basin water resources. If we want to identify the ways of response of runoff to climate change in semi-arid region in northwest of China, the study should be first based on the grasp of the long period evolvement rules of runoff. Based on the observed annual runoff data of the Wudinghe River during 1945-2012, the characteristic of the abrupt change had been diagnosed by employing the methods of Moving t-test technique and Mann-Kendall and Yamamoto. The analysis showed that the annual runoff of the Wudinghe River changed abruptly in 1972, in the year since, the decrease of the runoff is about 3.55×108m3 on average. Precipitation decrease about 6.28% but runoff decrease about 26.62% on average after the abrupt change of the Wudinghe River runoff during 1933-2012. Although precipitation was the primary factor to affect surface water resource, precipitation was not the main reason for runoff decrease compared with human activities. Then reconstruct the sequence of natural runoff of the Wudinghe River during 1933-2012 according to the significant correlation between precipitation and runoff before 1972. Morlet complex wavelet function was used to transform the sequence of runoff of Baijiachuan hydrologic stationin of the Wudinghe River during 1933-2012. According to wavelet to analyze the periodic characteristics of the natural annual runoff, the results showed that the average period of annual runoff change have multi-scale periods such as 35.5 a, 22.2 a, 16.8 a, 12.2 a, 9.3 a and 3.3 a. It will be able to calculate the influence degree of the natural runoff change because of human activities such as building a reservoir, building a dam that silting land for developing farmland, etc.
