The rapid growth of automobile industries has increased traffic flows and traffic related accidents in urban areas during the recent years. Traffic jams and traffic accidents have major impacts on people’s daily life. There has been a growing body of literature investigating the characteristics and reasons of traffic accidents. A number of studies have focused on the temporal patterns of accidents and revealed that more accidents occur in day-time than night-time, afternoon than morning. However, there is no general agreement on whether peak traffic accidents always happen during the rush hours. This study aims to analyze the spatio-temporal patterns of traffic accidents in Huicheng District in Huizhou City, China. Specifically this study examines the temporal patterns of peak traffic accidents and their relationship with nearby land use. The study reveals that peak traffic accidents do not coincide with rush hours. Motor-vehicles accidents, which account for most traffic accidents, concentrate near commercial facilities, especially in the late evenings. Motor-vehicles accidents on secondary roads peak in the late evenings, while those on main roads peak right after the rush hours in the morning and the afternoon. One possible explanation of such patterns is that traffic policing is more strictly enforced and drivers are more vigilant during the rush hours.
Road traffic networks in 17 cities of Anhui Province are taken as the study object in the article. It investigates that development of road construction in Anhui is from evenness and complexity, and the fractal dimensions of various road networks were calculated with the Hausdorff Fractal Dimension and the Dendrite Fractal Dimension of the fractal technology. And then the authors construct the weight dimension model measured the integrated road network. The various causes lead to the uneven development of traffic network, and there are obvious differences among these regions in Anhui. The result is that area size of the road network influences the fractal dimension of the road network. The authors divide 17 cities into three parts based on their area, and performs the correlation analysis between the weight dimensions, the fractal dimensions of the main road lines and the general economy indexes. The result shows that the fractal dimensions of the road network in various cities and the composite economic indexes are correlative. It can be explained that the evener is coverage degree of the road network, the more complex is the transport network and the better is regional economic development. To further seek coordination relations between highway construction and the economic development in various cities, the authors calculate the fractal dimensions of 17 cities introducing the fractal model of road construction scale-economic output. We discover that economic development exceeds the road scale in 6 cities, basically consistent in 4 cities, and economy development lags in highway construction scale in 7 cities. At the same time, if economic development dropped behind highway construction scale it would not necessarily mean that economic development was clear laggard; contrarily, if economic development was in advance to highway construction scale it would not necessarily mean that economic development must be good. It has relative relation between economic development and highway construction scale.
China has been stepping into a new spatial growing stage leaded by conurbation, which results in a new border region due to the interaction between the conurbations. Based on the differential analysis on the backbone industries, the article takes the conurbation as a relatively independent territorially economic system and puts forward the border effect model resulting from interaction between conurbations according to the basic principle, of which homogeneity brings about competition and heterogeneity induces cooperation. Xinyang City, located between the Wuhan conurbation and Zhongyuan conurbation, is took as the case study region. The research result shows that border effect model could measure the potential impacts on the border region from the interaction between the conurbations. For the current development stage, Xinyang City is exposed to a good intervention opportunity by the interaction between the Wuhan and Zhongyuan conurbations. In more detail, IO (intervention opportunity) remains the high level of 0.64~0.71 (the average level is 0.69 per year ) in 2000-2008 without the border effect emerging. During the time, UE ( border effect) fluctuates between 0.16 and 0.31 (the average is only 0.23), and the level grows to 0.37 dramatically in 2009. According to the analysis, the weak intervention capability of Xinyang City may contribute to the situation, which could conclude that the border effect is the result of external intervention opportunity and internal intervention capability. What is more, globalization and conurbation reconstruct the external development environment of the border region and exerts the important influence on it. The article divides the border region into three different development stage, which are localization-dominating, regionalization-dominating and globalization-dominating, represented by localization index (LI), regionalization index (RI) and globalization index (GI) respectively. This is a dynamic mechanism stage pattern different from classical characteristics stage pattern, by which we could seek the dynamic analysis and development direction of the border region. Through the empirical study of Xinyang City, a city is still situated in the localization-dominating stage, LI is large than 0.5 (except some year) during 2000-2008, and slows down to 0.45 in 2009; RI grows to 0.55 above. All data illustrate that Xinyang City beings to step into the regionalization-dominating stage, but the globalization development keeps in the initial level since GI has been remained below 0.001 2. The conclusion basically could testify the Xinyang City’s current development situation, which is corresponded with the initial industrialization stage by Chenery. So the article proposes that the optimization of internal development environment, and the advance of inner intervention capability and regionalization process would be the future development strategy direction.
The time reliability is an important indicator of bus services quality evaluation. The improvement of time reliability has much potential to attract more commuters to public transit and to reduce the congestion through modal shift from cars. The time reliability is one of the space-time characteristics of urban public transportation. At present, there is not much researches on bus service reliability from the time geography perspective. To aim at filling the gap, this article proposes an evaluation approach of time reliability for the urban public transportation in space-time process based on time geography. In this approach, four indexes, one-way punctuality index (OWPI), stability of one-way punctuality index (SOWPI), station punctuality index (SPI), stability of station punctuality index (SSPI), are included. The space-time path, which is a basic concept of time geography, is also used to describe the four indexes as a powerful tool. OWPI and SOWPI are the moderate level indexes to investigate the time reliability of bus line, while SPI and SSPI are the micro indexes for bus stations. In addition, SPI and SSPI are time reliability indexes from the perspective of passengers, and they can also be extended to micro and macro levels. Using GIS and GPS data, space-time paths of buses are formed to calculate the indexes, and 6 bus lines of Guangzhou BRT are given as examples. Moreover, the route length, land use types, period of day and number of stations are considered as influencing factors of time reliability. The relationships between these factors and time reliability are investigated respectively. As to the analysis results, in the same direction of a bus line, the time reliability of bus stations in the upper line is higher than that in downstream. The unreliability accumulation effect can be seen along the bus route. With respect to land use types, a higher reliability in commercial land is indicated, which can be interpreted as that commercial lands, which need better bus service since the commuters in such area, have more time constrains than others. With respect to period of day, the statistical results indicate the lowest reliability is in the morning rush hours since all commuters flock to the transit system at the same time. Meanwhile, a bus line with more bus stations shows lower time reliability as higher stop frequency reduces the arrival accuracy. Recommendations for improving time reliability are proposed in the analysis Recommendations for improving time reliability are proposed in the analysis, which includes rational number (no more than 30) if station of a bus line, and reasonable length of that, and providing better bus services in residential land plus in the morning rush hours.
Based on the “lake effect” hypothesis and urban spatial structure theory, a theoretical model of the lakes which influence the economy surrounding the urban is put forward in the paper, and the area surrounding Poyang Lake as a case is empirically analyzed. The result indicates that under the influence of Poyang Lake, the city distribution density and traffic network density in the area show a trend of first slowly increasing then gradually decreasing corresponding to the distance from lake, while they show a increasing trend when the distance further increases. Therefore, the area surrounding Poyang Lake was divided into three urban economic regions according to the extreme principle and special attributes. The empirical analysis clearly shows that the model not only can theoretically explain how the lakes affect the space differentiation of the urban economic regions, but also can provide a quantitative model that can be extended.
Using spatial analysis techniques, this paper quantitatively analyzes the relationship between the spatial distribution of 655 cities of China and the natural environmental factors including rivers, vegetation, relief degree of land surface (RDLS) and elevation using sotware such as ArcGIS10, ENVI4.5 and Visual FoxPro6.0. The results include the following several aspects. Firstly, the cities are strongly dependent on rivers and the dependence is getting stronger with the expansion of the cities. The cities’ sensitivity to rivers reduces as the distance from the cities to rivers increasing. Secondly, the number of cities is becoming larger with increasing vegetation rank generally. In other words, the better the vegetation condition is, the more the cities are distributed. The cities’ dependence on vegetation is strong and the dependence is getting stronger with the expansion of the cities. Thirdly, the number of cities is getting smaller with the increasing relief degree of land surface (RDLS) rank generally. That is to say, the bigger the value of relief degree of land surface (RDLS) is, the more the cities are distributed. Relief degree of land surface (RDLS) has a great impact on the distribution of cities and the impact is becoming stronger with the expansion of the cities. Fourthly, the number of cities is becoming smaller with increasing elevation rank generally. In other words, the number of distributed cities is getting smaller as the value of elevation increasing. Elevation has a great impact on the distribution of cities and the impact is getting stronger with the expansion of the cities. At last, the city development suitability was evaluated in different regions of China and the regions were pointed out which are suitable for city development. The regions consist of the Northeast Plain, the North China Plain, the Middle-lower Yangtze Plain, the Pearl River Delta and the Sichuan Basin. In terms of the natural environment, the small and medium-sized cities of high suitability regions have large development potential.
From the spatial scale of prefecture-level city and county area, this article establishes an evaluation index system of the urban comprehensive power of Zhujiang River Delta (ZJRD) urban agglomeration to analyze the urban comprehensive power in 1990, 1994, 2000, 2005 and 2009, respectively. Moreover, the spatial interaction level among the ZJRD cities and the potential value of each city are calculated using the improved gravity model and potential model. By these results, some GIS spatial analysis methods such as space thematic map expression method and space interpolation method, etc. are used to analyze the spatio-temporal evolution of the urban space interaction of ZJRD urban agglomeration in recent 20 years. The basic conclusions are obtained as follows: 1) The spatial contact among the ZJRD prefecture-level cities has been gradually strengthened as a whole, and the centrality of Guangzhou in the region is reflected. 2) At county-level scale, the linkage between urban area and counties under the same prefecture-level city, the linkage among urban districts of prefecture-level cities and counties in the Guangzhou-Foshan metropolitan region are strong, while the spatial linkage among other counties and cities is weak. The spatial linkage among most counties at the core region of ZJRD has been gradually strengthened as a whole, however, the spatial linkage among counties out the core region and the spatial linkage between the counties at the inner core region of ZJRD urban agglomeration and counties out the core region go up and down frequently all the way and have no discernible regularity. 3) The city potential values of Guangzhou-Foshan metropolitan region and Shenzhen-Dongguan-Huizhou metropolitan region are all strong and fluctuate pronouncedly. And the diffusivity of these two regions is also stronger than the other. The potential values of other cities are relatively lower and show no obvious fluctuation. 4) There is significant imbalance of the city potential between districts. The features and evolution laws of spatial differentiation and spatial diffusivity of the city potential in ZJRD urban agglomeration are obvious and unrest under stability.
In order to probe into the difference in energy consumption between regions in different developing period, the paper studies the changes in energy consumption of Fujian and Taiwan and their driving factors. The results indicate that: 1) The energy consumption gap between Fujian and Taiwan got greater then less, and Fujian consumed more energy than Taiwan for the first time in 2008. However, the energy efficiency of Taiwan grew by the mode of Power Function, which was far higher than Fujian. And the energy consumption stucture in Taiwan was more pluralistic. The share of clean and efficient energy in the final energy consumption accounted for over 80%. 2) The main driving factors of energy consumption change were roughly similar in both Fujian and Taiwan, but there were statistically differences between them. On the one hand, the change of energy consumption in Taiwan had more driving causes such as the proportion of tertiary industry and energy efficiency besides the same factors with Fujian. On the other hand, the ratio of spending on R&D to GDP, per capita GDP, the proportion of secondary industry and energy consumption had the opposite effects on the regions. The energy consumption in Fujian showed the trend of growth after driven by above factors, but Taiwan was in adverse. 3) Energy consumption of both regions was similarly affected by the consumption tradition, but the same factors had impacts differently in the two regions. In Fujian, the motorization influence was greatest, then followed by economic development and the rise of scientific-technological input, the proportion of secondary industry and population rising accounted for the least affect. In Taiwan, the motorization influence was most obvious, then the rise of scientific-technological input and energy efficiency took the second place, the population rising, economic development and industrial structural upgrade had the lowwest influence.
Settlements are places of habitation, production and the living for people. In this paper, we studied the spatial patterns and its influencing factors of settlement in the less developed area—Suzhou of Anhui Province. Five pattern indices (including the Area, the Mean Patch Area, the Patch Density, Average Nearest Distance and the Aggregation Index ) were computed and analyzed using FRAGSTATS, and the shape index and the spatial neighboring length and number between the residential area and other patches were calculated using ArcGIS. Here the Nearest Index that determines the type of residential area distribution were counted using the method of settlement geography, and the radius of cultivation were computed using the method of buffer zone. The results indicated that the settlement is the most broadly distributed and dominate the landscape patches. The mean of the residential area is small and the shape is simple but its aggregation index is high. The farmland is the type that has highest neighboring length with residential area, suggesting a complex and close relationship between them. The distribution of residential area is random. Farmland is the most important factor which effect rural settlement spatial pattern, rural settlements′ distribution obvious influenced by the central town. More than 50% of the residential areas are distributed in general highway within 1.4 km. By using the buffer analysis method, the settlement cultivated radius is calculated which can reveal the cultivated land distribution and the relationship between the settlement distribution and its influence factor. Through the GIS, the landscape pattern analysis and settlement analysis method, the spatial distribution pattern of the settlement differences and their impact factor can be revealed. It is the effective method to explore the landscape pattern formation mechanism. The research of the settlement in less developed areas of the landscape pattern is feasible. It is a guiding role to study the village layout and planning, discuss settlements and villages′ landscape and argue the relationship between the cultivated land and village.
Wetland ecosystem is a special natural complex under the interaction between land and water. Its functions are mainly decided by landscape pattern.With the support of GIS technology, RS images and Frag-stats3.3 statistical software, this paper studied the changes of wetland landscape pattern of costal wetlands in Yellow River Delta including the size of landscape area, landscape patch characteristics and the overall level of landscape pattern under different temporal-spatial scales of the Yellow River Delta in 2000 and 2009. The results showed that the coastline length and the total area of the coastal wetland in the Yellow River Delta show a rising trend as a whole in recent 10 years. The natural wetland area has a sharp reduction. Mean fractal dimension indices of the most landscape types are lower and the landscape fragmentation indices generally decrease. While the landscape diversity index, evenness index and contagion index all increase. Overall, the indices changes of wetlands landscape pattern reflect the profound impact from human activities including large-scale cultivation of dry farming fields and paddy fields, the development of salt farming industry and oil exploration, etc.. This study indicates that the human activities have become the main driving factor for landscape pattern changes in coastal wetland of Yellow River Delta. In the future, the coordinated development of the ecological environment protection and economic development should be focused on in the Yellow River Delta .
The loadings of total phosphorus and total nitrogen entering a lake were divided into two categories: point source and non-point source. The SCS (Soil Conservation Service) and the USLE (Universal Soil Loss Equation) models were used to calculate dissolved and particulate non-point source loadings, while the point source loading was estimated from the discharge of industrial, domestic and livestock wastewater. The mass conservation model of total phosphorus and total nitrogen in a lake was established, which was built upon the estimated input loadings of total phosphorus and total nitrogen entering a lake as well as the current concentration of total phosphorus and total nitrogen in the lake. Based on the calculated loadings entering a lake from the watershed and atmospheric deposition, along with the mass conservation model established, the previous annual average concentration of total phosphorus and total nitrogen in a lake was obtained by backward inference. Then, the reference condition of total phosphorus and total nitrogen, which was minimally impacted by human activities, could be established. The reference conditions of total phosphorus and total nitrogen in Chenghai Lake are 0.014 mg/L and 0.247 mg/L with the application of the proposed model. The reference conditions inference model is of clear physical concept, and less data required. Thus, the proposed methodology is applicable to other lakes under similar situations.
In this paper, the sediments and paleo-lakeshores data in Zhuye Lake and surrounding areas, the terminal lake of Shiyang River drainage basin, in the marginal area of the Asian monsoon, were synthesized and then the spatial and time scales around Zhuye Lake and in the drainage basin were discussed. In the spatial scale, this study compared the results of mid-Holocene geomorphology and lake sediments in Zhuye Lake, and we also studied the mid-Holocene sections in the middle and upper regions of the Shiyang River. In the time scale, nearly a hundred dating results in Zhuye Lake and the drainage basin were compared. Then it was concluded that there was a centennial-scale extremely dry interval occurring during 8.0-7.0 cal ka B.P. in Zhuye Lake, instead of the previous study which reported the dry interval during 7000-5000 cal a B.P.. And the centennial-scale extremely dry could be detected in the middle and lower reaches of the drainage basin, but the upper region was less affected. The centennial-scale extremely dry interval might be related to the changes in water and heat balance, and the characteristics of climatic conditions in this drainage lead to the different responses to the dry interval in the different locations of the drainage basin. There were no obvious evidences showing that the dry interval was related to the Asian monsoon weakening. In this paper, the time and spatial scales analysis of the dry mid-Holocene in Zhuye Lake provide some clues and ideas for the dry mid-Holocene studies in other parts of the Asian monsoon domain.
Using monthly average temperature data at 26 stations in Northeast China in 1961-2010 and the NCEP/NCAR monthly reanalysis data, the interdecadal characteristics of summer temperature anomaly over Northeast China is investigated. It is found that there are 4 different patterns of summer temperature anomaly over Northeast China by applying empirical orthogonal functions (EOFs) analysis to monthly mean summer temperature anomalies. The EOF1 presents a pattern with changes in the same direction, holding about 72% of the total variance contribution, and its time factors show multiple interdecadal variation. Three other patterns hold 10%, 4% and 3% of the total variance contribution respectively, showing north-south, east-west and mountain-plain anomaly patterns with changes in different direction, and the influence of ocean, terrain, and the difference of latitude. Multiple interdecadal variation of mode EOF1 has mutation properties further analyzed by mutation and wavelet analysis, and influenced by a period of 20 a, the time factors mainly were minus during 2007 to 2010, which should be paid more attention. Mode EOF1 is significant positive correlation with geopotential height in 500 hPa and U-wind in upper troposphere (Westerly Jet) of 30ºN-40ºN, presenting a global belt distribution. In northeast Asia, the positive correlation zone reaches 60ºN, and geopotential height in 500 hPa changes in nearly the same direction with the multiple interdecadal variation of mode EOF1. Mode EOF1 is significant positive correlation with sea surface temperature (SST) in Asian coast of Pacific, the Western Pacific Warm Pool (including the north-central areas of Indian Ocean), the south Pacific surrounding Australia, the North America coast of the Atlantic, the northern area of the North Atlantic drift, and the northern area of the equator in the Atlantic. It is also significant positive correlation with Pacific Decadal Oscilliation (PDO). Mode EOF1 is closely related with the multiple interdecadal variation of sea-air system in the Northern Hemisphere, and at the same it is influenced by global warming.
Long term (1951-2006) Surface Water Surplus (SWS) for growing season (May to September) over Northeast China is produced by NCAR CLM3.5, which is driven by daily observations from 102 meteorological stations. Temporal-spatial variability of surface dry/wet status is analyzed based on the CLM3.5 simulation. The results show that, 1) in growing season, 30 year (1971-2000) averaged SWS has relatively large spatial difference, with regional SWS ranging from 100 to 800 mm. Higher SWS value locates over eastern, southern and northern parts of analysis domain, indicating a wetter condition over the area. 2) Significant inter-annual and decadalvariabilities are detected in CLM3.5 results; 3) Over Northeast China the SWS has decline trend showing that the surface has been drying during past 50 years. The drying signal is also found in decadal variance of spatial distribution of SWS, and with 2000s showing most dramatic drying, it implies that in the condition of global warming the aridification over Northeast China would enhance; 4) The surface moisture condition is the combined effects of land surface process and climate change; its prediction requires the thorough understanding of surface water budget.
In this study, the spatial distribution and dynamic characteristics of extreme cool summer events in Northeast China were investigated. It unveiled that: the temperature variation of early summer could be used as a predictor to herald that of the whole summer in Northeast China. The extreme cool summer event was defined in this paper and it was divided into three kinds. Apparently, with the increasing latitude in Northeast China, the frequency of cool event increased too. Since 1990s, there only two cool events happened, but it could sweep over the whole region of Northeast China. The influence scope of cool event was closely related with the position and arrangement of cold vortex and blocking high. On climate mean state, the blocking high dominated over north of Northeast Asian and cold vortex governed over south of Northeast Asian at 500 hPa level, while the low-frequency Rossby wave disturbance, on the same phase, acted on the climate state, enhanced the dipole of “+,-” wave train, which was the significant dynamic mechanism that affected the strength and scope of unusually cool summer events. Additionally, owing to the effect of cold vortex and blocking high in the district of Okhotsk further east, the first and second types cool events more easily occurred in Heilongjiang Province, and part of Jilin Province. Blocking high in Baikal and Okhotsk area matched very well, in addition, cold vortex further south and Rossby wave strongly disturbed, were all benefit for the third kind type cool event occurrence.
Soil moisture characteristics of spring in Jilin Province and its influencing factors were analyzed with the routine statistics method and geostatistics method integrating spatial analysis technique on GIS, based on the soil moisture data and related data in Jilin Province in 2003-2010. The results were as follows.1）In spring, the soil water content of 0-30 cm was very different between the west and the east of Jilin Province, its spatial distribution showed an increasing trend from west to east. And the spatial distribution of soil water content in 10 cm showed more difference compared with the other 3 layers. With the increase of soil depth, the variation of spatial distribution kept descending, the soil water content increased in the west and the central, but it had no significant change in the east. In all 4 soil layers there were three low soil water content regions and one high region. The low regions were appeared in the west of Jilin Province, Yanbian and the south of Tonghua. And the high region was appeared in Baishan . 2）The soil water content data has better relativity between the closer soil layers. Compared with the west and central regions, the soil water content of 10 cm was correlated with other layers more closely in the east. And the correlation among the layers was the lowest in the central of Jilin Province. Additionally, soil field water-holding capacity and precipitation were the main factors that affect the soil water content in Jilin Province. 3）The soil water content affected more on the soil moisture in the east and the central than the west in Jilin Province. And the effect of precipitation on the soil moisture in the west and the central regions was more significant than that in the east of Jilin Province.
The multitime scale features and coupling relationship of precipitation, runoff and sediment discharge of Fenhe River Basin during 47 years between 1959 and 2005 were analyzed in the paper, by applying wavelet analysis method. The results indicated that there were two significant periodic variations at scales of 2-4 a, 14-18 a for precipitation, runoff and sediment discharge. And the main periods of them were nearly the same. This first main period was 16 years, while the second main period was 3 years. At the 3-year scale, the positive and negative phases about the curves of precipitation, runoff and sediment discharge had appeared frequently, and there are many mutation points. Most of the time the changes of precipitation, runoff and sediment discharge had the synchronization during 47 years. At the 16-year scale, the mutation points, recurring cycles of positive and negative phase for three hydrological time series had became less than the 3-year scale. At the same time, there is not always synchronization for three curves. The trends of precipitation, runoff and sediment discharge and their non-synchronization were closely tied to natural factors and high-frequent human activity. And it is very important for human activity to affect the trends.
The ecological risk of heavy metals of 10 counties in the rural area around the Poyang Lake were evaluated, and then pollution sources of heavy metals were analyzed through the gray correlation between heavy metal and nine socio-economic indicators. Results showed that Cd contents of vegetable soil around Poyang Lake were severely exceeded the national standard with an excessive rate of 90% .The other heavy metals were not exceeded excepting contents of Cu in some areas. Ecological risk of the vegetable soil around Poyang Lake area is slight, and the total risk index was contributed most by Cd, accounting for 66.53%~97.30%.The ecological risk of developed regions around the Poyang lake were higher than lower industrial level regions, indicating that industrial development make a important influence on the spatial variation of heavy metal pollution in soil around Poyang Lake. The socio-economic indices of vegetable production, industrial development, urbanization, transportation development have high grey correlation with heavy metals contents, and GDP and the amount of pesticides use show a weakest impact on heavy metals.
