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  • 2014 Volume 33 Issue 7
    Published: 10 July 2014
      
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  • The research on urban spatial expansion and its space-time stability in China since 2000
    WANG Kaiyong, QI Wei, DENG Yu
    2014, 33(7): 1195-1206. https://doi.org/10.11821/dlyj201407001
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    Municipal district expansion and built-up area expansion are two main forms of urban spatial expansion. They are unstable under high-speed urbanization in China. Geographic stability contains both stability of time and space. With the help of geometric methods, the paper constructs a coordinated system based on standardized values of built-up area and municipal district area. What's more, the paper draws spatial expansion paths of some typical cities from 2000 to 2010 and classifies them based on standardized mean value. Finally, three indexes which are called mov, tor and sd are used to calculate space-time stability. The results show that, (1) In recent years, municipal district expansion can often be found in the Yangtze River Delta region, Pearl River Delta region, southeastern Fujian and the capital cities of central and western China. However, built-up area expansion seems unpolarized and each urban agglomeration has high speed expansion. (2) The space-time paths can be divided into stable type and unstable type. Most of the stable types are LL, which means both municipal district and built-up area are below mean values, while most of the unstable types only have one transformation between HH, HL, LH and LL. (3) The cities with high rank are sensitive to mov & sd, which indicate stability difference between the cities and the whole country. But the cities with medium rank are sensitive to tor, which indicates interannual stability of a city.
  • Group decision-making on well-order renovation of urban villages：A case study of Guangzhou
    TAO Haiyan, ZHOU Shuli, ZHUO Li
    2014, 33(7): 1207-1216. https://doi.org/10.11821/dlyj201407002
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    Public participation has become one of the city planning processes with legal procedures, so studying well-order renovation of urban villages based on public participant is of great value theoretically and practically for exploring the implement mechanism of rebuilding in China. However an individual decision-maker who is lack of information because of his/her self-interest, knowledge, experience and other restrictions, usually only perceives local space environment, and evaluates partial alternatives according to his preference, i.e., only can be given partial evaluation list. In order to research spatial group decision making based on incomplete information, Kemeny local optimization, which is proposed by Cynthia Dwork et al., is introduced. Steps of aggregation and optimization are as follows: firstly, find all elements in partial lists; then use a simple power-iteration algorithm to obtain a reasonable approximation to the stationary distribution of Markov chain, and the Markov chain ordering is the aggregated initial ordering; last, in order to improve consensus ranking, initial list has been locally Kemeny optimized. The normalized Kendall tau distance was used to evaluate the level of agreement from all the decision makers regarding all the possible alternatives in a given situation. With the example of 52 urban villages in Guangzhou, three different types of decision makers among villagers according to their main source of income and one type of environmentalists are introduced respectively, who are evaluating and ranking the urgency of urban villages rebuilding from their individual preference and perspective. Furthermore, a group decision making solution is obtained by using Kemeny local optimization algorithm. The method is realized by Python. The normalized Kendall tau distance of group solution to four individual solutions is 0.2873, which indicates that the result of group decision-making with all the individuals' decision making has a good consistency. The research demonstrates that the method is useful in making the most consistent group decision while comprehensively considering advices from different interest group, providing a quantitate method for public participation in democratic decision making and scientific decision support to public policy formulation.
  • Out of place and place constructing in Oldbund in Ningbo
    CHEN Xiao
    2014, 33(7): 1217-1229. https://doi.org/10.11821/dlyj201407003
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    As an important part of urban leisure space, bar has developed rapidly in China in recent years. In occident, bar is closely associated with regional order and social issues. Besides, western scholars take the bar in the Third World countries as a global Western-cultural enclave and a place with regional power concentration. As a result, the research raises two questions: (1) In China, has bar street also become a Western-cultural enclave? (2) In China, what is the power relation between domestic and foreign consumers and how does this power relation exert influences on constructing locality at bar street? The study takes the concept "out of place" as a conceptual framework, which was proposed by Cresswell, an English scholar, and aims to explore the power structure in China's bar street, which is different from that in the Western countries. In detail, the study takes Oldbund Street as a case study, which is a bar street in Ningbo, China. The research probes into consumers' behaviors and compares their spatial selection decision between domestic and foreign customers by using the methods of questionnaires, interview and observation. The main findings of the study are: 1) In Oldbund street, the"out of place"refers to the phenomena that different national consumption habits lead to the spatial segregation between domestic and foreign customers. Especially, bars with Chinese consumers are likely to exclude foreign consumers from their existing space, which, at the same time, constructs the locality of the bar street. 2) Currently, domestic and foreign consumers are two important groups in locality construction, of which Chinese consumers are playing a leading role in constructing locality of the bar street in China. Chinese consumers not only do not regard bar as foreign people's consumption space any more, but also exclude them from their groups. 3) In the past studies, bar in the Third World countries is considered as Western-cultural enclave. Consumers in bar are mainly Western consumers and local elite who used to study abroad, while local people are excluded. However, in Oldbund Street, it presents another landscape that Chinese consumer plays the leading role and"anti-segregate" theWestern consumers. Bar, as an imported consumption space, has developed in China for more than 20 years. There have been a lot of bar streets in scale in large cities in China. Consequently, to explore the locality construction of bar is conducive to understanding the interaction between globalization and localization. Currently, the phenomenon that local consumers anti-segregate Western consumers in the Third World countries has yet receiving sufficient attentions in the geographical research. The concept of power relation, which is the term that distinguishes between insiders and outsiders in a place, has not been widely explored and discussed. As a result, further studies in this area are supposed to be highlighted.
  • Spatial-temporal analysis of economic growth in Central Plains Economic Zone with EOF and GRWmethods
    BAI Jingfeng, ZHANG Haijun
    2014, 33(7): 1230-1238. https://doi.org/10.11821/dlyj201407004
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    Combined with the national strategic requirement of coordinated development of industrialization, urbanization and agriculture in Central Plains Economic Zone, selecting the data of per capita GDP from 1988 to 2012, this paper, by adopting the natural orthogonal function (EOF), analyzed the spatial-temporal characteristics of economic growth in Central Plains Economic Zone, and revealed the main driving force of economic growth and evolution with the aid of geographically weighted regression (GWR) model. The first modal of EOF analysis showed that the spatial distribution of the economic growth, on the whole, in Central Plains Economic Zone is out of phase along Beijing-Guangzhou Raiway (BGR), and that economy west of the BGR grows faster than that to east of the BGR and their corresponding time coefficients showed the obvious interannual change, and parts of region to the east and west of the railway have nearly 10 years of development cycle. The second mode reflected the annual anomaly of economic growth in some parts of the zone, and the phase distribution of spatial pattern in southwest and northeast of the region, and the interannual fluctuation of its corresponding time coefficients is more obvious. GWR analysis showed that the importance of factors that result in the change of per capita GDP in the Central Plains Economic Zone is different in space. The per capita net income of rural residents boasts the greatest influence on the economic growth of the Central Plains Economic Zone, and there is a positive correlation. Resources endowment is the second largest influencing factor, and also positively correlated with economic growth. The economic location is the third influencing factor, followed by the secondary industry, the level of urbanization, and agricultural machinery total power. Agricultural machinery total power has the least influence, and is negative correlated with economic growth. The factors that influence the economic growth in the Central Plains Economic Zone showed a clear longitudinal zonality. Therefore, the uniqueness of different administrative regions should be considered in the formulation of regional development policies.
  • Structure and evolution of economic linkage network at county level in Central Plains Economic Zone
    LI Yating, PAN Shaoqi, MIAO Changhong
    2014, 33(7): 1239-1250. https://doi.org/10.11821/dlyj201407005
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    With the rapid development of economic globalization and regional economic integration, the various contacts between cities and regions have become stronger and have a characteristic of network. As a result, regional economic linkage has always been a hot issue in economic geography and regional research. Researches on regional economic ties have provided theoretical basis and research paradigms in economic zone. However, current researches on regional characteristics are insufficient in regional economic ties, especially in less developed areas. Moreover, traditional research has mostly used the same threshold to establish economic networks in different periods, thus the change of the connectivity could be clearly identified, but the whole network structure of economic network and the roles of cities and key links in the network are difficult to be identified. If the same index was used to determine the threshold respectively at different time, it would be convenient to analyze the network structure and the roles of the cities, while it would be hard to identify the change of the connectivity. This paper, based on the gravity model in combination with network analysis of GIS which is used to acquire the matrix of the shortest time between any two counties, taking the Central Plains Economic Region as an example, calculates the economic linkage intensity between counties in 1996 and 2010, and analyses the network structure and its evolution characteristics by setting the same and different threshold separately. The conclusions can be drawn as follows: (1) The connectivity of the economic network has greatly improved in the Central Plains Economic Region, and the economic development and improvement of transportation is the main cause for the increase of network density and facilitation. (2) The connectivity among nodes is very different, and a small number of nodes hold the absolute network power, in which Zhengzhou and other four core nodes are particularly prominent. The linkage framework presents a transverse "T"-shaped pattern, and increasing the connectivity of eastern nodes will be helpful for constructing the cross-shape development axis. (3) The network has core-periphery structure and polarization trend, and the core region has the enlarging influence and radiation on the adjacent region. To strengthen the connectivity of nodes in the edge area will improve the regional integration development. (4) The connectivity of nodes tends to agglomerate by the "hub-andspoke" network structure around the secondary core nodes, the construction and evolution of the cross-shape development axis and the "米"-like development zone will facilitate to form multiple hub-and-spoke nested economic network. (5) Zhengzhou and other prominent nodes have become the "brokers" in the network due to their strong connectivity, but some nodes with low degree values act as the "structural holes" between the cluster regions. It is necessary to raise the ability of the connectivity of the "broker" nodes and the low degree value nodes by improving the economic and transportation conditions.
  • Identification and morphologic expression of Lunar impact craters
    WANG Jiao, CHENG Weiming, ZHOU Chenghu, ZHAO Min
    2014, 33(7): 1251-1263. https://doi.org/10.11821/dlyj201407006
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    Lunar crater data is the basic support data for the study on lunar morphology, the exploration of moon as well as the other lunar scientific research. Its comprehensiveness and accuracy are the measurement of a naiton's science and technology level, and even important indicator of overall national strength. In this paper based on the Chang'E-1 image, DEM and Clementine UV/Vis data, we detected 106,030 craters with a diameter of more than 500 m in the method of image processing combined with professional knowledge. According to the accuracy assessment like size-frequency cumulative curves and geometric error evaluation, the extracted craters only had an average error of 15.50 km and an error rate of 10.85% was also limited in the accuracy range. On the basis of named craters and their morphological parameters, which were organized by the International Astronomical Union, we set up a complete morphological parameter system consisted of 106,030 craters' morphological parameter attribute data. Furthermore we applied the object-oriented data model namely Geodatabase to organize all the lunar craters data for there is no set of mature database containing the most comprehensive information of lunar crater. This lunar crater database organizes the spatial and attributes data to construct an entire relations database system including the spatial part and the attribute part. The location, spatial relationship and other spatial data were converted to raster form stored in the spatial database and the data characterized craters were positioned in the attribute database which described seven categories of 52 indicators such as the overall size, shape, slope, direction, central peak and radiation grain of the crater. This database not only integrates the management of spatial data and attribute data, but also achieves the function of data storage, retrieval, processing and application. This work can provide mass basic data for data mining and applications of lunar science research and a reference for other resources database construction. The lunar crater database will be better perfected by updating and maintenance works in the further research.
  • The contributions of leaf area index and precipitation to surface energy balance in the process of land cover change
    LIU Fengshan, TAO Fulu, XIAO Dengpan, ZHANG Shuai, WANG Meng, ZHANG He, BAI Huizi
    2014, 33(7): 1264-1274. https://doi.org/10.11821/dlyj201407007
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    Leaf area index (LAI), which has interaction with a variety of elements such as precipitation in the process of land use and cover change, is an important influencing factor of the surface energy balance. But its contribution to the surface energy balance in the process of land use and cover change is unclear. This article emphatically isolated the impact of LAI on surface energy balance, in order to recognize the relative role of land cover and LAI in surface energy balance. The research objects include: three kinds of land cover, i.e. farmland, forest and grassland in northeast China, the corresponding LAI monthly data (annual average 1.21, 1.64 and 0.73 (m2m-2), respectively), and three arbitrary kinds of precipitation amount (double, normal and half) in 2003. Firstly the Simple Biosphere model 2 had been validated against net radiation, sensible heat, latent heat, and temperature at the study sites, and showed well performance on yearly change trends. Then the effects on surface energy balance of different combinations of land cover and LAI data under different rain amount conditions were studied using the model. We found that, (1) land cover change had the biggest impacts on net radiation, with annual average (Wm-2) about 14.5 compared with less than 1.57 and 0.49 for LAI and precipitation influence; (2) LAI mainly altered the partitioning of net radiation into latent and sensible heat flux, i.e. bigger LAI obviously increased (decreased) the ratio of latent (sensible) heat flux in net radiation at farmland and grassland, and LAI variation had less influence on latent and sensible heat flux at forest; (3) precipitation played an important role in net radiation partitioning, that is latent heat flux increased with more precipitation, but half times precipitation amount had more sharp effect than double times precipitation amount; (4) surface soil moisture was regulated by precipitation and LAI, and had an opposite variation tendency against latent heat. We also showed that the relationships between LAI and surface energy balance components at monthly scale were coincident with that at yearly scale. Our results proved the importance of LAI in surface energy partitioning into latent and sensible heat flux in the process of land use and cover change.
  • Simulation of the permafrost distribution on Qilian Mountains over past 40 years under the influence of climate change
    ZHANG Wenjie, CHENG Weiming, LI Baolin, TONG Chiming, ZHAO Min, WANG Nan
    2014, 33(7): 1275-1284. https://doi.org/10.11821/dlyj201407008
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    Permafrost is a soil medium which is extremely sensitive to climate change, so climate change has an important impact on permafrost. In this study, based on altitude-response model, the elevation data (DEM), longitude data, latitude data, mean annual air temperature data (MAAT) and the vertical lapse rate of air temperature (VLRT) are used to derive permafrost distribution in each decade on the Qilian Mountains over the past 40 years. For accuracy of simulation result, all these data except VLRT were transferred into a raster format and stored by WGS-1984 geographic projection and the same spatial resolution (0.001°, about 100 m). VLRT data can be obtained mainly based on the results of previous studies, which shows that the temperature decreased 5.5° by an increase of each 1000 m in elevation in the Qilian Mountains. Through analyzing, MAAT has a close relationship with altitude, longitude and latitude respectively. As for the MAAT data, linear multiple regression analysis between MAAT, DEM, latitude and longitude data was carried out for each decade. The simulation results are compared based on the Map of Snow, Ice and Frozen Ground in China, the interpretation results including 93 key permafrost point landforms can be used to test the accuracy of the simulation results, which were mainly based on field survey data, remote sensing image and DEM data for manual compilation of the Geomorphologic Atlas of People's Republic of China (1:1,000,000). The overall simulation results have a high accuracy, which can reach more than 80%. Using the altitude-response model, the areas of simulated permafrost distribution on the Qilian Mountains in the 1970s, 1980s, 1990s, 2000s, are 9.75×104 km2, 9.35×104 km2, 8.85×104 km2, 7.66×104 km2, respectively. The permafrost distribution area shows a decreasing trend over the past 40 years. Through the further analysis of the simulation results, from the 1970s to the 1980s, 1980s to 1990s, 1990s to 2000s, the rate of the permafrost loss was 4.1%, 5.3% and 13.4%, respectively, which shows an increasing trend and there exists a leap growth from the 1990s to 2000s. This research can provide an effective method for a better understanding of the dynamic changes of alpine permafrost distribution on the Qilian Mountains for a long series period.
  • Reconstruction of cropland spatial patterns for 1726 on Yellow River-Huangshui River Valley in northeast Qinghai-Tibet Plateau
    LUO Jing, ZHANG Yili, LIU Fenggui, CHEN Qiong, ZHOU Qiang, ZHANG Haifeng
    2014, 33(7): 1285-1296. https://doi.org/10.11821/dlyj201407009
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    In this study, first we revised the taxes-cropland area data in historical documents and estimated the cropland area in 1726 (the fourth year of Emperor Yongzheng's Reign in the Qing Dynasty) of Yellow River-Huangshui River Valley (YHV) which is located in northeast of Qinghai-Tibet Plateau. Subsequently, the cropland area was allocated into grids with a resolution of 2 km by 2 km under the help of GIS technology. The results show that the cropland area of YHV in 1726 was 1.427×103 km2, among which, 64.7% was cultivated by the minority as well as 35.3% was cultivated by soldiers and chieftain. The arable land of YHV is little due to the harsh natural environment. Crops can be found in some 47% of all grids and these grids were distributed in the Huangshui River basin, Beichuan River basin, the mid-lower reaches of the Datong and Yellow River. In terms of intensity of land use, the YHV had a low reclamation index in 1726. The reclamation index of 68.3% of all grids was less than 10% and only 1.4% of all grids had a reclamation index greater than 40%, which was attributed to the harsh environment and governmental policy. In addition, the spatial difference of the land use intensity was obvious. The reclamation index of Xining County was great on the whole and the mean value reached 13.5% at grid scale.
  • Surface modeling of sunshine percentage in China based on a modified version of HASM
    ZHAO Na, YUE Tianxiang, ZHAO Mingwei
    2014, 33(7): 1297-1305. https://doi.org/10.11821/dlyj201407010
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    Sunshine percentage is one of the important factors that influences the computation of sunshine hour and solar radiation. The computational results of sunshine percentage will undoubtedly affect the relevant researches. In order to solve the error problem that had long troubled the interpolation method, Yue developed a novel surface modeling method, High Accuracy Surface Modeling (HASM), based on the fundamental theorem of surfaces which makes sure that a surface is uniquely defined by the first and the second fundamental coefficients of it. Numerical tests have shown that HASM is much more accurate than the classical methods such as kriging, Inverse Distance Weighted (IDW) method, and spline. Surface modeling of Digital Elevation Model (DEM), ecosystem change and soil properties also indicate that HASM has increased interpolation accuracy. Despite its popularity, however, a common phenomenon is found that the result of HASM is not optimal since the theoretical basis of it is not complete. To improve HASM's simulation skills in interpolating sunshine percentage in China, this research gives a modification of HASM, namely HASM.MOD, which introduces the mixed partial derivative term, considers the local details of the surface and is theoretically perfect. The introduction of the mixed partial derivative term in HASM.MOD reflects the local warping of the surface, namely its deviation from tangent plane at the point under consideration. We then use Gauss synthetic surface to validate the performance of HASM.MOD and HASM. HASM.MOD is then used to simulate the monthly mean sunshine percentage by using observed data from 752 stations for the considered period (1950-2010). We also compare the performance of HASM.MOD with those of HASM and other interpolators: kriging and inverse distance method (IDW). Numerical tests and real world studies show that the simulation accuracy of HASM. MOD is higher than that of other methods in this study. As the basic geographical data, the sunshine percentage produced by HASM.MOD can provide support for other applications.
  • The evolution of network gravity center for rural residents tourist flow in China
    CHEN Chao, MA Haitao, CHEN Nan, CHEN Huyue
    2014, 33(7): 1306-1314. https://doi.org/10.11821/dlyj201407011
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    Rural residents tourist flow is a hot topic in tourism geography. The gravity center can comprehensively reflect the spatial diffusion and agglomeration of tourist flow network. This study is a basic work for regional layout of tourism industry and scientific allocation of tourism resources. Based on tourist flow data of domestic rural tourists (overnight tourists) in the sample survey of China's 2002-2008 domestic tourism, the paper constructs network gravity center models of the rural residents tourist flow, tourist flow direction, and shift distance to reflect the path of rural residents tourist flow by using SAS software and Google Earth. The results show that: First, the center of rural residents tourist is located in the west and north of the center of the destinations. Both of the centers show the evolution path of "southeast by southnortheast by east". The centers in 2004 became a yielding point of southwest-northeast changing direction. Second, both centers apparently incline to the southwest compared to the centers of economic revenue, population and inbound tourism. Third, the spatial dimensions of center shifting distance from 2003 to 2005 are greater than those in other periods. The east-west(the difference of longitude is 0.99°) moving speed of China's rural residents tourist flow center is faster than that of the south-north direction (the difference of latitude is 0.65°). Fourth, rural residents tourist destination center is located in the southeast of rural residents tourist center, shifting slightly from east to north; The distribution of both centers is characterized by a phenomenon of spatial dislocation, revealing regional difference and spatial imbalance of rural residents tourist capacity and destination attraction. The study may provide a new approach for further development of tourist market and the prediction of tourist flow.
  • The research on inbound tourists’ cognition sequence for spatial image of urban destinations in Xi’an
    ZHANG Chunhui, BAI Kai, MA Yaofeng
    2014, 33(7): 1315-1334. https://doi.org/10.11821/dlyj201407012
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    It is critical to use spatial cognitive process to discuss the human-environment inter-action and geospatial cognition. It is hard to draw consistent conclusions when we discuss the spatial cognitive process in the academic circle, and the key point of contention is the dominant element of spatial cognition and the type evolution rule of cognitive map. About the dominant element of spatial cognition, there are three theoretical perspectives, namely routes-based viewpoint, landmarks-based viewpoint and integration development viewpoint. About the type evolution rule of cognitive map, numerous empirical studies have questioned the hypothesis of cognitive map changing from sequential type to spatial type which was put forward by Appleyard. Compared with the general permanent residents, tourists' destination spatial cognitive process has a unique rule. So more attention to tourists in related studies would provide new empirical evidence for the study of spatial cognitive process, and promote the development of spatial cognitive process theory with more universal sense. Therefore, taking inbound tourists in Xi'an as the research objects, the study extracts and counts data about cognitive map from 324 questionnaires, and analyzes spatial image characteristics of Xi'an urban destination. And the study especially discusses the dynamic change process of types and constituent elements of cognitive map with tourists' duration of stay, and accordingly proposes inbound tourists' cognitive process of spatial image of urban destination. The results mainly include three aspects: (1) There are 4 types of cognitive maps of Xi'an inbound tourists, in which spatial type is major, and individual type, sequential type and hybrid type are secondary. This is different from residents' urban cognitive maps in which sequential type is dominant, indicating that there is a significant difference between tourists and residents in cognitive style of urban spatial image. Inbound tourists' spatial environment knowledge of destination is derived from direct experience with tourist attractions scattered in the city, and from indirect sources such as travel maps. This is why spatial type is dominant in inbound tourists' cognitive maps. With the second highest frequency, the individual type of cognitive map not only reflects the integrity of tourists' spatial memory, but also highlights tourists' sense of place towards destination environment, and represents a special development stage of spatial cognition. (2) From cognition elements of spatial image, the frequency of landmarks is the highest, while the frequency of district, boundary, node and road is lower. Spatial orientation and wayfinding, as well as the need of exploring social and cultural significance of symbols and establishing an emotional connection with the destination, these four factors jointly prompt landmark to become a dominant element in inbound tourists' cognitive maps. Converging at Bell Tower, east, west, south and north streets are easily perceived together by inbound tourists, and they appear mostly together in tourists' cognitive maps. Consequently, route element is second only to landmark element in average number per cognitive map. The Bell Tower, which is the center, combined with the city wall and east, west, south, north streets constitutes a basic framework of Xi'an inbound tourists' spatial image of urban destination. (3) Inbound tourists' spatial cognitive process of Xi'an urban destination includes two sequences: in the matter of dominant type of cognitive maps, the evolution sequence is "spatial type + individual type→spatial type→sequential type (hybrid type) →individual type"; and in the matter of dominant element of spatial cognition, the evolution sequence is "landmarks→ landmarks+routes→landmarks". This spatial cognitive process indicates that inbound tourists' attention focus of spatial image of urban destination turns from the identity to the structure, then to the meaning.
  • Research of trend variability of precipitation intensity and their contribution to precipitation in China from 1961 to 2010
    XU Xingchuang, ZHANG Xuezhen, DAI Erfu, SONG Wei
    2014, 33(7): 1335-1347. https://doi.org/10.11821/dlyj201407013
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    Precipitation intensity is one of important meteorological factors determining occurrence of extreme hydro events and variation of available water resources. China is a country with frequent floods/droughts and unbalanced demand/supply of water resources. To reveal the climate change rhythms and deal with water resources issues, it is valuable to research the temporal and spatial variations of precipitation intensity. Using the daily precipitation measurements during 1961-2010 from 756 stations across China, we researched the inter-annual and inter-decadal variations of precipitation intensity for the light, moderate, heavy and storm rainfall, respectively, and quantified their impacts on total precipitation. The overall trend of variations of precipitation intensity is positive. Such a positive trend was mainly observed in the region south of Qinling Mountains and the Huaihe River. Among the four grades of rainfall, the light rainfall intensity has the strongest positive trend; whereas, the moderate, heavy and storm rainfalls have no significant trends. The precipitation intensity also had obvious inter-decadal variations. At decadal scale, the precipitation intensity was weak in the 1960s and 1970s while it was strong since the 1980s. The contribution of precipitation intensity variations to total precipitation spatially occurred in the order of‘large-small-large-small'from east to west. The storm rainfall plays a dominant role in the variations of total precipitation in the eastern China, particularly in the southeast of Northeast China, west of North China and middle of Southwest China. The light, moderate and heavy rainfalls play a dominant role in the variations of total precipitation in the western China.
  • Study on comprehensive assessment of ecological security in Changbai Mountain Region based on multi-hazard natural disasters risk
    NI Xiaojiao, NAN Ying, ZHU Weihong, Choi Yunsoo, LIU Guoming, LIU Chen, YAO Kuo
    2014, 33(7): 1348-1360. https://doi.org/10.11821/dlyj201407014
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    The study, taking the Changbai Mountain Region as the study area, used DEM data, observational data of metrological station, remote sensing image data, thematic map data and statistical data as the main data sources, combined with the metrological disasters, volcanic disasters and geological disasters risk level distribution data in Changbai Mountain Region and based on PSR model. The study established the ecological security assessment index system based on multi-hazard natural disasters risk from three aspects of ecological system pressure, ecological system state and human environmental response. According to the index system, Range Method was used for index standardization, AHP was used to determine the weights of the indexes, and Comprehensive Index Method was used to calculate the ecological security index based on multi-hazard natural disasters risk. According to the ecological security criteria based on multi-hazard natural disasters risk and combined with the existing literature, the ecological security index based on multi-hazard natural disasters risk was divided into five grades of Insecurity Grade, Less Insecurity Grade, Criticality Security Grade, Less Security Grade and Security Grade, and then the ecological security level based on multi-hazard natural disasters risk in Changbai Mountain Region was then assessed based on pixel level and administrative divisions. The results showed that: the ecological security level based on multi-hazard natural disasters risk in Changbai Mountain Region reflected significant spatial differences, and represented a gradual descending trend from the central to the eastern and western ends, as well as the southern and northern sides. The area of each grade ranked as follows: Criticality Security Grade > Less Security Grade > Security Grade > Less Insecurity Grade > Insecurity Grade, and the percentages were respectively 40. 31%, 35. 77%, 10. 23%, 7. 17% and 6. 52%. In addition, the mean ecological security index and the ecological security grades were counted and analyzed based on administrative divisions. The ecological security level based on multi-hazard natural disasters risk in counties and cities ranked as follows: Changbai County > Antu County > Fusong County > Helong City > Linjiang City, and the structure of the grades varied from city to city. The Criticality Security Grade was mainly found in this region, the ecological environmental quality was at general level, which was between security grades and insecurity grades, and the system service function was damaged to some extent and was degraded. The ecological structure changed, the anti-interference ability was low, and the self-recover ability was low. The ecological problems were evident and the ecological disasters occurred occasionally. The main driving forces of the ecological environmental problems were human factors.
  • Risk assessment on storm flood disasters of different return periods in Huaihe River basin
    ZHANG Zhengtao, GAO Chao, LIU Qing, ZHAI Jianqing, WANG Yanjun, SU Buda, TIAN Hong
    2014, 33(7): 1361-1372. https://doi.org/10.11821/dlyj201407015
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    A new method is used to study the risk assessment on storm flood disasters of different return period in the Huaihe River Basin. The method is to make the maximum amount of daily precipitation (PMP), which is regarded as one of the major hazard factors, combined with other 11 kinds of second indexes to carry on the risk assessment. PMP is obtained by using different types of distribution functions fitting annual maximum sequence. The investigations show that the high-risk areas of flood disaster of the Huaihe River Basin are located in Mengwa detention area, Funan County, Anhui Province and the lowlands around it, the moderate-highrisk areas are in the central and southwestern parts of the basin and parts of the eastern basin. The southern-central and northern parts of the basin are low-risk areas. With the return period from 10 a to 1000 a, discrete spatial distributions of PMP in the southwestern basin are greatly increasing. In the eastern basin, the risk is gradually weakened. Moreover, the spatial distribution of flood disaster risk in the Huaihe River Basin shows that the moderate-high-risk areas remain stable. The high-risk and low-risk areas decrease gradually and the ratio of the total area decreases from 8.3% and 42.4% to 3.2% and 30.8%, respectively. The values of high-risk areas keeps invariant but regional concentration has become more obvious. For moderate-risk areas, the ratio increases from 28.3% to 40.9%. Overall, the changes of spatial distribution patterns present that major disasters have reduced but small disasters occurred frequently in the eastern basin. The high-risk areas of the western basin are vulnerable to flood, while the northern and central-southern parts of the basin are relatively safe.
  • Spatial-temporal characteristics of prolong-type rice chilling damage and its relationship with climate change in Northeast China
    XI Zhuxiang, MA Shuqing, JI Lingling
    2014, 33(7): 1373-1382. https://doi.org/10.11821/dlyj201407016
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    Northeast China is one of the major rice producing areas in China, because of the lack of heat, and rice growth is more sensitive to temperature. Temperature becomes the major limitations to local rice growth. Analysis of spatial-temporal characteristics of rice chilling damage in Northeast China under the background of climate warming is of important significance for rice chilling damage defense and its response to climate change. Spatial-temporal characteristics of prolong-type rice chilling damage and its response to climate change in Northeast China were analyzed based on classification index of prolongtype rice chilling damage and daily temperature data from 101 stations during 1951-2010, and by using the accumulative anomaly, correlation coefficient, and climatic trend rate and tendency coefficient. The results show that the frequency for prolong-type rice chilling damage is larger to the west of eastern Inner Mongolia (Mengdong), the boundary between eastern Jilin Province and Heilongjiang Province, the frequency for this damage is smaller in the southern-central Liaoning Province. The frequency of severe prolong-type rice chilling damage is higher than that of light and medium damages during 1951-2010 in Northeast China. The light, medium and severe prolong-type rice chilling damages show a downward trend, prolong-type rice chilling damage presents a trend of rapid decline particular after 1994. The downward trend is more significant in the central Heilongjiang and the northwest of Mengdong region, and the downward trend of prolong-type rice chilling damage shows no significance in Liaoning, the south of Mengdong region, the south of Jilin and the north of Heilongjiang. Prolong-type rice chilling damage in Northeast China has a better relationship with climate warming. The average temperature from May to September and prolong-type rice chilling damage has obvious anticorrelation, the average temperature from May to September rises by 1℃, and prolong-type rice chilling damage in Northeast China reduces about 45 times. The periodic change of the average temperature from May to September and prolong-type rice chilling damage shows the obvious reverse phase.
  • Distribution and pollution of soil heavy metals in hilly upland around Pingdingshan coal mining area
    CHU Chunjie, ZHOU Jinfeng
    2014, 33(7): 1383-1392. https://doi.org/10.11821/dlyj201407017
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    An attempt was made to investigate the influence of mining activities upon the hilly upland soil around Pingdingshan coal mining area. Topsoil samples were collected from this area. Subsequently, the contents of five heavy metals, including Cu, Zn, Cr, Ni and Pb, were determined by means of the standard analysis methods of soil chemical composition. We analyzed their distribution characteristics at different altitudes and at different distances off the wind direct from the mining area, and evaluated the conditions of soil heavy metal pollution by adopting geo-accumulation index. The results are shown as follows. 1) The accumulations of heavy metals mentioned above were different from each other at different extents in the hilly upland soil around Pingdingshan coal mining area, in which Ni was the most significant, followed by Cr, Cu and Pb in turn. 2) The higher concentrations of five heavy metals at different altitudes were found in the mining zone, near slope bottom and slope top respectively. On the other hand, the highest concentrations were found within a distance of 50 m off the wind direct from the mining area, and contents of five heavy metals decreased as the distance increase. 3) Contents of Cu, Cr and Pb increase with the slope reduction, while the lowest contents of Zn and Ni were found in soils of slope from 5° to 15°. However, land use patterns showed no effects on the distributions of heavy metals in the upland soil around Pingdingshan coal mining area. Moreover, the contents of five heavy metals between forest land, grassland and arable land were not significantly different. 4) Cu, Zn, Cr, Ni and Pb pollutions were all found in the mining zone, and Cu, Ni and Pb pollutions were also found on the slopes below the mining zone, yet soils in slopes above the mining zone were only lightly polluted by Ni. Cu and Ni were the main pollution elements in downwind direction, with light to intermediate pollutions at different distances. Cr and Pb showed light pollutions within a distance of 50 m off the wind. Otherwise, Zn still kept clean in downwind direction. 5) Ni, Cu and Pb contaminations in the hilly upland soil around Pingdingshan coal mining area were caused mainly by human activities. In contrast, Zn and Cr were chiefly from natural sources.