With rapid social and economic change around metropolitan, peri-urban phenomenon, as a transitional process from rural to urban area, is becoming one of the most important research topics for urban studies. However, current research on Chinese peri-urbanization is generally focused on the description of its unique characteristics of an identified peri-urbanization area at a specific year, and there are very few studies on the dynamic change of peri-urbanization areas and the comparison of different peri-urbanization areas. Taking Hangzhou municipality as a case, this paper aims: (1) to explore how to identify peri-urbanization areas through establishing an indices system; (2) to empirically identify the spatial distribution of peri-urbanization areas in Hangzhou municipality and further to identify the different spatial evolution types of peri-urbanizations areas in the period of 1990 to 2000; and (3) to compare the different characteristics of different spatial evolution types of peri-urbanization areas, such as the lasting peri-urbanization area and the newly-developed peri-urbanization area by using Xiaoshan District and Fuyang Municipality as respective examples, and thus to enhance our understanding on the interior differences among peri-urbanization areas.
Through the analysis of related literatures at home and abroad about the measurement of urbanization level and its dynamic changes, we found that China's urbanization has entered a rapid development stage and the motive forces for the development of urbanization have changed enormously. Therefore, the scientific measurement of urbanization development level and quantitative comparative analysis of its ideal powers will be particularly important to promote the level and quantity of regional urbanization. Based on the urbanized connotation, the paper constructs the appraisal index system of the synthesis level of the regional urbanization embarking population urbanization, economic urbanization, life-style urbanization and regional landscape urbanization. With the method of entropy, the generalized analyses to the evolution of the urbanization level of Jiangsu Province from 1991 to 2005 are carried out. The result shows that the urbanization of Jiangsu Province has been enhanced continuously. At the same time, the urbanization mainly represents the fast development of the economic urbanization and the regional landscape urbanization. But the population urbanization is becoming weak to the overall contribution of the regional urbanization and lagging behind other urbanizations. Economic urbanization, life-style urbanization and regional landscape urbanization have improved constantly. Meanwhile, they are turning harmonious gradually. On this basis, the multiple linear regression models are linked to the comparative analysis of the main urbanized impetus of Jiangsu Province from 1991 to 2005. Then the result is that the market forces, the intrinsic forces, the exterior forces and the administrative forces are the main powers of the urbanization development of Jiangsu Province. And the market forces and administrative forces are the ideal powers that promote the urbanization and the economic development of Jiangsu Province.
Current research of China's urban social space emphasizes more on the macro-level than on the micro-level social space. There are relatively few research papers on the micro-level social space, such as the characteristics of residential quarters. Based on the methodology of qualitative research and deep interviews, taking a number of peripheral communities around Peking University campus as research cases, this paper tries to analyze the characteristics and their driving forces of the social space of peripheral communities of campus in Zhongguancun. The authors found that the social space of peripheral communities of campus in Zhongguancun experienced the transformation from the period of homogeneity to that of heterogeneity. Social stratification and social differentiation exist in these communities. Higher fluidity happens in such communities, and is correlated with not different social class but the same one. The social network link is strong within the same social class, however, it is weak among different social classes. To the floating population from outside Beijing, they tend to bring some of their network links in their hometown to Zhongguancun or Beijing, and they often affiliate with not residents of other social classes in their communities but friends or relatives, who come from their hometowns and live out of these communities. As a result, to some extent, segregation of social class exists in peripheral communities of campus in Zhongguancun. Under the operation of both universities and market, the social spatial structure of the peripheral communities of campus in Zhongguancun exhibits a complex pattern of both chaos and order. Finally, the authors attempt to put forward a model of interlaced mechanism of the forming of social space of the peripheral communities of campus in Zhongguancun at the macroscopic, mesoscopic and microcosmic levels. Under the background of market economy, a new social space, which is charactered by higher fluidity and incompact social network, has been built both by external population and by original residents in the peripheral communities of campus in Zhongguancun. Most important of all, this new social space will help to understand the relationship among the fluidity, the features of social network and the maturity of social space.
The study on the village pattern evolution is important and significative to constitute the policy of land utilization in the new period and to build new socialist countryside. The Huang-Huai-Hai Plain, located in the central part of East China, is the important farm belt, and consists of multitudinous villages with a high population density. In this region, the marketization level and urbanization level are high because of close to the coastal developed areas, and the interior development problems of the villages are prominent such as a mass of farmlands being occupied, and too many houses being abandoned. So it is one of the representative regions to research problems of village development. Progress in the study related with countrysides, settlements, farmers, and villages have been reviewed. Studies of the village pattern evolution on macroscopic scale were much more than those on microscopic scale, so microscopic studies should be strengthened to better understand village development. The Wulou village in the central part of the Huang-Huai-Hai Plain was chosen as a typical case. The face-to-face interview and the global position system (GPS) measurement method were used in the study. The main results are as follows: Firstly, the Wulou village went through a series of evolution pattern including the absolute tardiness development before the establishment of People's Republic of China in 1949, the relative tardiness development before the implementation of the economic reforms in 1978, the fast expansion in the 1980s, the steady scale in the 1990s and the recessionary development in the early 21st century. In the meantime, the roads and ponds in the village have also been changed correspondingly. Secondly, the main factors of the village pattern evolution included economic improvement, the change of social structure, urbanization and the effect of national policy. However, population variation was still the decisive factor. Thirdly, the change of village scale was not obvious before the implementation of the economic reforms in 1978, the expansion of village scale was prominent from the 1978 economic reform to the 1990s, and the empty and abandoned houses have increased largely since about 2000.Fourthly, the previous village expansion attributed to four aspects as follows: No family planning after 1949 resulted in population increasing enormously; the economic development enabled people to improve their habitations; the status of nuclear families (namely a family consists of few people which only include husband, wife and their children in general) was enhanced step by step; and farmers were not conscious of the importance of protecting plantations. Finally, the causes leading to abandoned houses lately are that the urbanization and market economy are becoming or will become the direct drive of the village hollowing at present; the profit of planting grains is so low that it has become the important impetus of the village hollowing; and the fast increase of population has been successfully controlled by the policy of family planning in China since the 1980s. Furthermore, according to the status quo of the village development in the study area and the social development demands, the corresponding countermeasures have been brought forward.
According to the comparison of the spatial structures of crude oil flow in China at the beginning of the 21st century and the end of the 20th century, this paper analyzes the changing characteristics of the spatial structure of crude oil flow and its main influencing factors. Based on the analysis, this paper educes a flow model from the Interaction Model (W. Alonso Model) to simulate the regional crude oil flow. This model, together with the conception of Traffic Location Index, aims at analyzing the leading factors in forming regional crude oil flow through calculating the output indexes (ρ1) or input indexes (ρ2). The Output Index or Input Index reflects the regional oil transportation condition in support of regional oil output or input, if ρ1 or ρ2 >1, then the advantageous regional transportation condition enlarges the output or input, and the forming mechanism of crude oil flow in these regions is called transportation-driven type; if ρ1 or ρ2 =1, then the regional transportation condition only supports the output or input of the regions' oil surplus or oil gap, and the forming mechanism of crude oil flow in these regions is called supply-driven type or demand-driven type. Calculated with the data from Regional Energy Balance Table of China in 2006, this paper derives the ρ of every study region, according to which the mechanism of output flow is divided into, the transportation-driven and supply-driven two types, the mechanism of input flow is divided into three types of the transportation-driven, demand-driven and supply-and-demand-driven, and the mechanism of exchanging flow is divided into two types of the handing-on and distributing, and then, this paper analyzes thoroughly the development characteristics of the representative regions of each type. Furthermore, this paper generalizes the spatial diversity of the forming mechanism of oil flow in China, analyses the problem in it, and from a perspective of optimizing the spatial allocation of all kinds of flow mechanism, suggests to foster Shanxi into a new exchanging center between the East and the West China, and to strengthen the exchanging function of Guangdong between the South and the North.
Existing literature on regional income inequality in China has paid little attention to rural households, especially those in less industrialized rural areas. This study uses the data from a sample survey conducted in April 2007 on 1251 rural households from 11 villages of Henan, the largest less developed agricultural province in China, to examine rural inequality and factors contributing to rural income. It is found that rural income at the household-level was significantly different across rural villages and among rural households within a village. The Gini indices for all sample villages were over 0.39, and even over 0.4 for some villages. The income per capita in the poorest 10% of households only accounted for one thirty-seventh of that in the richest 10%. A quantitative modeling analysis indicates that regional factors, such as cultivated land area, landform types, farming structure, location as measured by distance from the closest county seat, transportation, and non-agricutural development have all played a significant role in explaining the difference. Furthermore, different factors have been found in villages with different income levels. In the lower income group of households, the cultivated land area was more important than other factors, implying that people in those families heavily relied on grain farming. In comparison, the agricultural types contributed more significantly to income for the households in the medium income group, while economic background, non-agricutural development level, geographical location, and transportation were more sensitive to income level in the households of high income group. This finding leads support to the hypothesis that the factors affecting rural development differ in different stages of development. The results of this study also provide a comparison with another study in the same province but based on township-level administrative areas. Most conclusions are consistant notwithstanding; this study provides some further factors improving understanding of rural development.
For many years, regional development and disparities issues have been important concerns for both academic and political leaders.This paper analyzes the disparities in variation of regional economies in China over 1999 to 2004 period, using prefecture level data. Firstly, disparities in economic growth of each prefecture level city are analyzed by classifying them into several growth patterns in terms of GDP and GDP per capita. Accordingly, combining both GDP and GDP per capita growth patterns, each prefecture city is classified into five integrated growth patterns: (1) large, usually with higher level of GDP per capita, and dynamic (LD), (2) small but very dynamic (SD), (3) large with higher level of GDP but relatively slower growth (LHS), (4) small, usually with lower level of GDP per capita, and lagging (SLL), and (5) small in total GDP but with higher level of GDP per capita, and lagging (SHL).Generally, good-performing cities (of LD and SD type) are concentrated in the eastern parts of China whereas slow-growing cites such as those of SLL type are, to a greater extent, distributed in middle and western parts of China. It is also found that there is a tendency of intercity disparity on economic growth within eastern regions. Moreover, to better understand the role of regions in national growth and explore the factors of uneven economic growth of regions in China, changes in GDP share of cities in total are decomposed by using modified OECD/SIU approach. The first thing is to decompose GDP share of cities into GDP share of cities in the province they belong to and that of the province in the nation. Statistics show that most of the good-performing cities are primarily driven by their own success rather than the success of the province they belong to. Then GDP(for secondary sector)are decomposed into five factors: capital productivity, capital per manpower, specialization, employment rate and growth rate of population. We conclude that capital is a major factor that led to GDP (secondary sector)growth among cities in China.In most cities, capital productivity is declining, the extent of which contributes to the disparities among different types of cities, while capital per manpower has generally great positive impact on economic growth of cities at all levels. In addition, the tendency of decrease in specialization indicates that there is a change in specialization towards sectors with technology and capital-intensive industries which have relatively low employment. Therefore, labor has less impact on GDP growth of the secondary sectors than capital.
The urban park is an important part of urban recreational spatial system. However,currently recreation products and service provided by urban landscape architecture fail to meet the development of visitors’ diverse requirements. Thus,how to plan,design and manage applicable recreation activities in order to fulfill visitors’ needs becomes a crucial issue to urban park managers. Evaluation is the foundation of planning and management,so the paper proposes a technical process of "designing,evaluating and decision making" for urban park recreation management. In the empirical study,four urban parks in Wuxi City are taken as examples. First,the paper develops an evaluation index system of recreation activities in urban park from the perspective of visitors,which consists of three hierarchies and 13 indexes. Second,the paper collects data from the survey on visitors of four urban parks and evaluates recreation activities in these urban parks. The results are as follows:(1) environment quality of urban parks in Wuxi City is better than service quality; (2) pricing and particular activities for the aged are supposed to be improved; and (3) the recreation management of tourism urban parks should pay attention to crowd and visitor impact management,while the recreation management of recreation urban parks should focus on developing recreation activities to be more convenient for local residents. Finally,the paper advances a method of 'Expectation Disconfirmation-Experience Level’ management. Using data collected,nine types of recreation activities are located in the "ED-EL" matrix and recommendations are given on the development of recreation activities in four urban parks in Wuxi City.
Trails are one of the fundmental facilities on which tourism activities are performed. They provide safe access to non-roaded areas, support tourism opportunities and protect natural resources by concentrating visitor traffic on resistant treads. However, increasing tourism use, coupled with poor planning and management, has led to negative impacts on trails. In order to study the tourism impacts on trails, Huangshizhai scenic spot in Zhangjiajie National Forest Park was selected to systematically research by means of after-the-fact analysis. 30 sampling plots were chosen. The results indicate that tourism activities have already negatively impacted on trails in Huangshizhai scenic spot with indictors evaluation and characteristics analysis. The main conclusions are as follows: (1) the rate of trail extension is 13.5% and there are 6 kinds of spatial forms in this scenic spot; (2) the occurrence rate of trail erosion including incision and soil loss within the sample plots is 73.3%; (3) the number of trail damage's site is 14; (4)the soil hardness along trails increases markedly and the average soil hardness increase 0.5m away from the trails is 197.5%; (5) the content of organic materials of soil by the trails decreasing due to ring trail trampling;ad (6) the percentage of vegetation cover reduces obviously along the trails. And the impact on trails on top of the mountain is the greatest, followed by the downhill trail, and that of the uphill trail the smallest. In addition, strong correlations between high levels of trail degradation and higher frequencies of visitors were found. Based on the findings, some management suggestions were put forward.
It is one of the seven main topics in the study field of the tourism destination image that the tourism destination image changes along with time. Based on the model of tourism destination formation that is a general framework of tourism destination image, this paper proposes a study method to analyze the perceptive difference of the tourism destination image along with time, evaluates the changes of pre/post tourism destination image from the overall point of view, which extends further the assessment method of tourism destination image focusing on the destination multi-dimensional attributes. The main idea of this method is to evaluate and contrast the change of cognitive, affective and overall image between pre-visit and post visit using the quantitative methods such as principal components analysis and paired sample t test. This paper applies this method to Tiantangzhai scenic spot of Anhui province and finds that the tourism destination image of Tiantangzhai scenic spot between pre-visit and post visit changes steadily to a certain degree.The overall image' assessment of Tiantangzhai scenic spot is positive either in pre-visit or in post visit without changes, which shows that the tourism destination image maintained relative stability. However, the specific perception value numbers between pre-visit and post visit have certain changes and differences, the assessment value number of the evaluation factors is decreased or increased respectively. Overall, the perception value number of pre-visit tourism destination image is larger than that of post visit, indicating a higher level of expectations of tourists to Tiantangzhai scenic spot. Managers of Tiantangzhai scenic spot should take some measures according to the situation of the perceptive differences of the tourism destination image between pre-visit and post visit, such as strengthening management and the construction of scenic areas, upgrading and improving the tourism destination image. Through the empirical study, this paper draws conclusions as follows: The empirical results achieved the expected goals, and validated that the tourism destination image has the characteristics of stability again. This method that compares the changes and the difference degree of pre/post tourism destination image from the global point of view is feasible, thus it can provide a useful reference for the follow-up studies.
As a significant approach to geographic information visualization, map making is practiced by not only professional cartographers but also more and more general public. However, the latter is often rarely equipped with knowledge of cartography. Instead of comprehensive theories and methods of cartography, simplified mapping skill might be suitable for them to make maps with respect to their special purpose. As a preliminary study, this paper aims to explore and build a conceptual model of duality for geographic information visualization. Dualistic analysis is employed to establish an easy-to-be-understood framework which could be followed as a "map-making guide". First, the paper introduces the theories of dualism in terms of other disciplines, such as geography, linguistics and philosophy. Then, with semiotic linguistics as a normal form, the methodology of dualism for geographic information visualization is elaborated from the perspectives of the signifier and signified of geographic information visualization. Our analyses demonstrate that: (1) geographic information is of duality, such as the duality of time and space, the duality of instant and interval, the duality of geometry and attributes, the duality of qualitative and quantitative approaches, etc.; and (2) map design is also full of various dualities such as the duality of the entire format of a map and individual symbols, the duality of outline and fill of a symbol, the duality of shape and size, the duality of color and texture, and so on.
Various spatial interpolation methods are widely applied to climate map production. The quality of climate spatial interpolation depends on the spatial variation of climate factors, the spatial distribution of climate stations, and the interpolation method. For examining the relationships between station distributions, interpolation methods and interpolation quality, 599 climate stations in Texas, US with 30-year precipitation records are collected and 27 station samples are designed by regular or random sampling. The spatial patterns of Annual, January and August precipitation data are investigated using exploring spatial analysis such as spatial statistics, spatial autocorrelation testing, and semivariogram modeling. Five methods, i.e. , Kriging, IDW, local polynomial, regularized spline and thin plate spline, are used in the spatial interpolation of Annual, January and August precipitation data for all the station samples. The interpolation results, in terms of cross-validation errors, known-point check errors, and linear regression of the known values versus predicted values, are compared and discussed. Four findings are generalized from this case study. First, precipitation data usually have patterns such as obvious spatial trend, high-level spatial autocorrelation and stable semivariogram model. Nevertheless, the spatial patterns may vary by sample stations and seasonal changes. Considering these spatial characteristics, the exploring spatial data analysis is necessary and essential for climate spatial interpolation. Second, increasing the sample size of climate stations, the interpolation accuracy will be improved. But at a reasonable number of stations, increasing the sample size, the interpolation accuracy will not be improved obviously. Third, when the observation samples are scarce, different methods usually give very different interpolation results. When the samples are relatively rich, general methods tend to create similar results. Fourth, considering the intrinsic limitations of the general spatial interpolation methods, the authors suggest to explore the local relationships between climate factors and geographic variations, and to develop a knowledge-based interpolation method by introducing geographic variables and local regression models. The weighted linear regression of precipitation versus elevation for northwest Texas and the geographic weighted regression for entire Texas have shown the potentials of such new approaches. It is also argued that exploring spatial data analysis and knowledge-based spatial interpolation are critical for high-quality climate data interpolation.
This paper reconsiders the man-land relationship in West Liaohe River Basin through the analysis of settlements' environment and takes the key district of ecologically fragile area, where the improvement of the environment is urgently needed, as the focus of the study. Based on the research of three agricultural reclamation periods in West Liaohe River Basin since Holocene, the paper brought forward that the location of the settlement can be classified as the first choice and the territoriality. Because of the fragile environment in West Liaohe River Basin, there exist not only the environmental differences but also a total different characteristics of the first choice and the territoriality. In the two aspects of height and topography, sloping field of 400-600 m contour is the first choice. It is not only the main immigratory area in each agricultural reclamation period, but also the area with a longer duration of human activity. Region outside 400-600 m contour area belongs to territoriality. Secondary migration is a most important step of compromising the man-land relationship. It is also the beginning of agriculture and planting in territoriality. Moving out of the first choice and moving into the territoriality as the secondary immigration have been through all previous agriculture reclamations in West Liaohe River Basin, which is most prominent during the reign of Emperor Guangxu in the Qing Dynasty. Agricultural reclamation in West Liaohe River Basin was a main process of the environmental change from grassland to farmland. Because of the environment differences between the immigrants' first choice and territoriality, agricultural reclamation in territoriality would bring a more serious disturbance to the environment, thus, this kind of area is not only the focus of environmental issues, but also the key district where the improvement of the environment is urgently needed.
The Shahe profile in Dongling, Liyang, the Caoxieshan site in Weiting, Suzhou and Maqiao site in Maqiao town, Shanghai are chosen as the major research objects on stratigraphy, from which we analyze and study the paleo-corroding surface, deposit characteristics, sporo pollens, chemical elements, 14C dating and climate transformation curve transformed by chemical composition from the stratum of the Maqiao site in Shanghai, combined with the analysis of the regional paleoenvironment and environmental archaeology as well as the research results of the temporal and spatial distribution of archaeological sites since the Neolithic Age in the Taihu Lake region. The research results indicate that the climate of Liangzhu epoch in the Taihu Lake region increasingly changed towards colder and drier than that of its former time in Holocene Megathermal period, however, much more time of it was still warmer and wetter than today. In the end of Liangzhu epoch, the climate was at the lowest position and showed rapid and violent fluctuation, which matched well a long time course of sea-level falling that was reflected by the paleo-corroding surface of Liangzhu epoch. The flood accumulation layers, the buried ancient trees, the buried archaeological sites and cultural interruption, etc. prove the existence of the ancient floods; the iron manganese concretion and the ancient wells under water such as the Taihu Lake, Chenghu Lake and the Taishidian in Zhouzhuang etc. today reflect on the dry periods or drought events. The background of Liangzhu cultural development was that the sea-level in the Taihu Lake region was slowly falling, the area of fresh-water lakes and marshes were increasingly decreasing, which made the land increasingly exposed; in the meantime, the climate was slightly better than that of today. In 4300-3800aB. P., the low sea-level, the abnormal climate as well as the frequently occurred floods and droughts were the environmental background of Liangzhu culture towards the decline and fall.We think that the direct reason for the decline and fall of Liangzhu culture is more complicated than we have imagined ever, however, the frequently occurring floods and droughts as well as the abnormal climate should be seriously fatal hit for Liangzhu people living on the paddy growing, fishing and hunting.
Hospital infection has proved to be one of the most important routes of SARS transmission, and nearly a quarter of those infected are medical staff in Guangzhou in South China. However, its potential to control epidemic of SARS is unclear. Detailed records of this epidemic have allowed the development of spatial analysis methods that capture the main features of epidemic spread in space, and the impact of SARS accepting hospitals. SARS epidemic comes from Guangzhou City in South China. SARS epidemic in Guangzhou is a sample to study epidemic's sudden outbreak in urban areas, which can help us to understand which is the risk factor that affects epidemic process and how epidemic spreads. Spatial points are gained according to the family addresses of SARS infectors. Mathematical models are used to express quantitatively the transmission center and confidence interval of epidemic areas. Spatial pattern of different SARS infection groups and their change are analyzed compared with that of SARS accepting hospital weighted with the number of accepted SARS patients. The result shows that there is a clear trend for the transmission center to approach the center of SARS accepting hospital, and their patterns are consistent with that of SARS accepting hospitals. Medical personnel and the other infectors are affected equally by SARS accepting hospitals. SARS accepting hospitals have an impact on the SARS epidemic in Guangzhou, which experiences a strong- weak- strong process. This paper contributes to a better understanding of the spatial spread for SARS and other new infectious diseases in urban areas, and provides a support for public health contingency plans.
Regulation and rebuilding of landscape structure are the keys to redevelop the regional safe ecological pattern. The eco-environment of the 13 provinces in northern China is relatively fragile. In order to understand the eco-environment feedback mechanism and seek a way to optimize landuse/cover spatial pattern under ecological security, the temporal and spatial dynamic changes of the ecological security in northern China during the 11-year period from 1989 to 1999 is analyzed based on the landscape ecology theoretic, semivariogram and GIS in this paper. The results show that: (1)The eco-environmental quality in the study area showed an obvious decreasing trend. The eco-environmental quality in the areas with high ecological security decreased more slowly on the whole. The main reasons are that the eco-environment is better,flexible and steady. So it has higher capability to resist the outside disturbances. (2)The level of ecological security in the east region was more secure than that in the west and central regions.For each sub-region, the level of ecological security in Northwest China was the lowest; Inner Mongolia was secondly; Shaanxi and Shanxi provinces that lie in the Loess Plateau were in the third place; North China was higher than the above three sub-regions; and the three provinces in Northeast China were the highest. (3)The changes of the indexes of ecological security could be divided into three types: ①the indexes of the level of ecological security increased firstly and then decreased, including Beijing, Liaoning, Shanxi and Qinghai; ②the indexes of the level of ecological security decreased and then increased, including Heilongjiang, Jilin, Inner Mongolia, Ningxia; ③the indexes of the level of ecological security decreased continuously, including Tianjin, Hebei, Shaanxi, Gansu, and Xinjiang. During the ten years, the levels of ecological security decreased at different speeds except Northeast China.
Based on daily records of precipitation from 687 weather stations over China from 1990 to 2000, we interpolate and validate daily precipitation interpolation using DAYMET. The technique interpolates on a systematic grid daily precipitation from surrounding stations based on the principles of a weighted Gaussian filter. In this study we calibrated DAYMET using the China climate data base and modified DAYMET considering the different effects of the dimensional orientation of surrounding stations on the local point interpolation, which allows us to interpolate daily precipitation for any location within the country. We validated the technique using crossing validation, and compared the MAE to the result of the methods named gradient plus inverse distance squared (GIDS). Our results can be summarized as follows: without modification, the mean absolute error(MAE) of daily precipitation interpolation using DAYMET is 1.8mm, the value for GIDS is 2.2mm,and the MAE for annual total precipitation is 29.8% for DATMET. After modification, the MAE of annual precipitation for DAYMET is 27%. The reason for considering high MAE of the two methods is that the weather stations in China are sparsely distributed in space, especially in Western China. To decrease the MAE of interpolation, the addition of the precipitation observations from hydrological station network should be considered. We chose Wudinghe Basin located in Western China with an area of 30261 km2, only 3 weather stations, but 93 precipitaition stations of hydrological station network, to test it. With the surrounding 30 climate stations, the interpolation MAE of annual precipitation is 77mm(28%) for DAYMET,but aided by precipitation stations of hydrological station network, the MAE is 48mm(12.1%)。
The thermal condition, occurring frequency, risk index and climatic risk probability of the maize chilling damage in Northeast China were analyzed, and the synthetic climatic risk index and model were developed. Northeast China was divided into five climatic risk areas(highest, higher, moderate, lower and lowest)using synthetic climatic risk index. The risk evaluation model of climate-economic loss of the chilling damage was developed using synthetic climatic risk index,considering the maize’s output and proportion of planting area.On this basis, Northeast China was divided into five typical damage areas of economic loss risk, including the highest, higher, moderate, lower and lowest one. Then the authors put forward relevant measures to reduce the damage risk in different areas. The difference in damage risk is obvious in different areas. The northern and eastern parts of Northeast China are the highest climatic risk areas, and southwestern Jilin and most parts of Liaoning are the lower ones. The central part of Northeast China, the northern part of Heilongjiang and eastern Jilin are the highest risk areas on economic loss, western Jilin and northeastern Liaoning are moderate, the central and eastern parts of Liaoning are lower, and southern Liaoning is the lowest one even without risk. Though the climate becomes warm, the supply-demand relation of thermal condition of maize production is still tense as a result of the increasing proportions of maize production(especially the late-ripe species). Therefore, the chilling damage risk is still high in most parts of Northeast China, and we should positively control the chilling damage under the condition of climatic change.The main measure to reduce the damage risk firstly is to improve the planting structure, adjust the maize variety proportion in different areas; and secondly is to use the cultivating technique of resisting the damage for promoting the resistibility.
Glacier and lake variations in the Mapam Yumco Basin were studied by integrating series of spatial data from topographic maps and Landsat images in four different periods of time:1974,1990,1999 and 2003.The results indicate that glaciers and lakes in the Basin both retreated and advanced during the last 30 years. As a contribution to the studies of the impact of climate change on glaciers and lakes in high-altitude closed basins of the western Himalayas, we present spatial and temporal variations of glaciers and lakes in the Mapam Yumco Basin on the Tibetan Plateau, by means of Geographical Information System and Remote Sensing techniques. Our results show that both glacier and lake areas in the Mapam Yumco Basin decreased from 1974 to 2003. Glaciers in the basin have receded due to the warmer climate, in total by 7.53 km2 (0.26 km2 a-1 or 0.25 % a-1) during 1974 2003 (c.f. 0.07 % a-1 nearby the Yamzhog Yumco Basin, and 0.18% a-1, the mean glacier recession rate over China since the 1960s). During the same period, lake area decreased by 34.16 km2 (1.18 km2 a-1 or 4.37 % of whole lake area in the basin) in total, where decreased by 1.43 km2 a-1 on average (with lake shrinkage amounting to 1.70 km2 a-1 in some areas and lake growth to 0.27 km2 a-1 in others) during 1974-1990, by 1.55 km2 a-1 (with lake shrinkage amounting to 2.15 km2 a-1 in some areas and lake growth to 0.60 km2 a-1 in others) during 1990-1999, while enlarged by 0.66 km2 a-1 (with lake shrinkage amounting to 2.24 km2 a-1 and lake growth to 2.89 km2 a-1) during 1999-2003 over the past three decades. It is suggested that both enlargement and reduction of lakes were accelerated, which might be an indicator for an accelerated water cycle process over the Tibetan Plateau in a warming climate condition.
Geostatistical methodology becomes an important tool for spatial prediction and uncertainty analysis. In terms of scientometric analysis and methodology development, advanced research for geostatistical methodology from 1967 to 2005 has been proposed in this study. First, its developing trend, application and patterns were identified; its development mode, suitability and choosing principles were then summarized. Development mode could be summarized as five transformations from stationary to non-stationary, single-variable to multivariate, parametric to non-parametric, linear to non-linear and spatial static to spatiotemporal dynamic geostatistics. Finally, the future researches were preliminarily discussed in this field, which is of great significance to geostatistical methodology and applications in the future. It includes: 1) developing new methods for variogram estimation to reduce the analytical complexity, 2) refining uncertain geostatistics to reflect hybrid uncertainties (input/output dataset, model structure, model parameters), 3) exploiting spatiotemporal/multi-point geostatistics and its algorithm/software to simulate complex realizations, 4) developing hybrid approach of process-mechanism and geostatistics to comprehensively uncover potential process-mechanism, in spite of the difficulties within the process simulations, and 5) expanding geostatistical-based decision-making under uncertainty, which supports the risk-based decision-making in social work, environmental pollution, agricultural production, public health, etc.
Water shortage, flood prevention and disaster mitigation are important problems awaiting to be dealt with in the Weihe River of Shaanxi Province. Under this situation, floodwater utilization would become an important way to realize comprehensive management of resources and the sustainable development of regional economy.In Guanzhong area which is located at the lower reaches of the Weihe River. The Weihe River is the biggest branch of the Yellow River, passing through Gansu, Ningxia and Shaanxi provinces. The middle reaches of the Weihe River is located in Shaanxi Province, with broad water ways, many shoals and scattered water flow. The lower reaches of the Weihe River is located in Xianyang, with serious channel siltation and small gradient. The flood resulted from heavy rain is the major disaster in these two areas. In general, the floodwater takes up about 33.1%-39.3% of the total runoff annually; the silt is about 60.1%-74.3%, where all data are mean values. It can be seen that a great deal of water and silt comes from the floodwater. By analyzing features of water, the quantity of silt coming from the upper reaches of the Weihe River, and the channel siltation, we establish the criteria as the initial values to evaluate the floodwater utilization; that is, the flood peak with a velocity of 2000m3/s in the middle reaches of the Weihe River, and that of 3000m3/s in the lower reaches of the Weihe River. According to these criteria, based on calculations we obtain the annual average quantlity of the available floodwater and silt from Linjiacun to Wijiabao is 4.038×107m3, and 6.83×106 t respectively, the quantlity of the available floodwater and silt from Weijiabao to Xianyang is 9.139×107m3, and 6.05×106 t respectively, and the quantlity of the available floodwater and silt from Xianyang to Huaxian is 1.617×108m3, and 1.843×107t, respectively. It is necessary to establish the risk management system to gain the optimal effects of flood prevention, water supply and ecological protection.
Urban River is an important part of urban ecosystem. There are close relationship between stream construction and its ecological function. The form and evolution of stream construction is controlled by geology, topography, soil, climate, vegetation and human activity at local area. At present, human activity, especially urbanization has become the major factor influencing the stream structure. In order to study the effect of urbanization on stream construction, taking Shenzhen city, a rapid urbanization area as a case, which is one of the most rapid urbanization areas in China, by using Strahler classification and Horton laws, this paper analyzed the effect of urbanization on stream length, stream density, bifurcation ratio of rivers, ability of bifurcation of rivers and fractal dimension etc. The result exhibited that: (1) The stream length, stream density and stream number all decreased, especially for the lower order stream from 1982 to 2002. and (2) the ratio and ability of bifurcation decreased of all the watersheds. The stream construction was simplified with time. The fractal dimension of stream construction also decreased with time. (3) The stream construction changing characteristic was different for different watersheds due to the effect of urbanization level. This paper suggested: (1) to improve planning and implement blue-line, strengthen the management of river net and add it to the content of urban planning and managing; (2) to protect the stream in the process of land use change; and (3) to strengthen the control of soil and water erosion, thus decrease the yield of river sediments.
