Loading...

Table of Content

    15 January 2001, Volume 56 Issue 1 Previous Issue    Next Issue
    A GIS Based Model for Calculating of Flood Area
    LIU Ren yi, LIU Nan
    2001, 56 (1):  1-6.  doi: 10.11821/xb200101001
    Abstract ( )   PDF (331KB) ( )   Save
    In this paper, a model of flood area display and damage evaluation is discussed, which adopts seed spread algorithm to calculate and visualize flood area based on a DEM data set and under the condition of a given water level of flood. The raster image containing flood area is overlaid with raster data converted from thematic vector maps such as land use map and related to other socio economic data, and then quantitative evaluation of flood damage is achieved. There are two different cases, the so called “non source flood” and “source flood”, for determining flood area based on DEM and under the given water level condition. Non source flood corresponds to the case with well distributed and large area rainfall where all the low lying land may have a flood disaster, and in this case all the points with elevations below the given water level should be included in the flood area. The “source flood” is the case of flood (e.g. from bank burst) flushing through the surrounding lands that needs to consider “circulating” condition. Because flood may be obstructed by ring structures or high lands, thus it can only cover the place where it flows and reaches. One of the computer processing methods suitable for source flood is the seed spread algorithm. The principle of this method is to select a representative pixel as a seed and to examine its contiguous pixels outward along 4 or 8 directions. The pixels, contiguous to it and meeting the given conditions, become seeds, and then contiguous pixels to the new seeds will be examined in the same way. This process repeats until an aggregation of the pixels which meet the given conditions on a certain plane are obtained. Adopting seed spread algorithm for source flood area calculation is just to achieve an aggregation of pixels, which satisfies the connectivity requirement and the given conditions of water level. The initial position of seed pixel should usually be selected on the characteristic points, e.g. adjacent to a reservoir dam or stream boundary. The precision of flood area calculation is mainly determined by spatial resolution of the DEM, the area on the ground is represented by each pixel; whereas the accuracy of flood area calculation, to a great extent, is dependent on the precision of the DEM’s pixel value or elevation. Once the area below the flood water level has been calculated, the flood damage evaluation can be calculated by overlaying the flood range with thematic maps and by relating to other socio economic data. All thematic maps were converted to raster data because algorithm of the overlay analysis implemented in raster format is relatively simple and computing is fast. In order to improve accuracy of the flood damage evaluation it is necessary to accurately register and georefer all raster layers before overlay analysis. The calculation results of flood damage evaluation are generally represented by tabulation, which is a kind of classified statistics of flood damage data, e.g. a table representing total area of every land use type in different administrative divisions. The results of flood area calculation and damage evaluation can also be visually and dynamically provided in the forms of graph, image, 3D or virtual reality. The model has been successfully applied in the “Zhejiang Provincial Water Conservancy Management System” developed for a national project.
    References | Related Articles | Metrics
    Effect of Apple Base on Regional Water Cycle in Weibei Upland of the Loess Plateau
    HUANG Ming bin, YAMG Xin min, LI Yu shan
    2001, 56 (1):  7-13.  doi: 10.11821/xb200101002
    Abstract ( )   PDF (239KB) ( )   Save
    Weibei Upland in southern part of Loess Plateau is a commercial apple base where the increase of apple planting area has seriously affected the regional water cycle. This paper studies the effects of different land use patterns on hydrological parameters. The main results are as following: (1) The initial and steady rates of infiltration in apple orchard were higher than those in grassland, naked land and farmland. Their initial rates of infiltration were 0 823 cm/min , 0 215 cm/min, 0 534 cm/min and 0 586 cm/min respectively. Their steady rates of infiltration were 0 45 cm/min, 0 038 cm/min, 0 191 cm/min and 0 155 cm/min respectively. (2) No runoff in apple orchard was produced in the 8 events of observed natural rainfalls, but it was produced in winter wheat, corn and alfalfa plots where runoff coefficients reached 2 39%, 1 58% and 0 31% respectively. (3) The transpiration of apple trees was very strong, leading to gradual depletion of the ascendant soil moisture. The average soil water contents of 3~9 meters soil profile in Changwu plots with apple trees of 14 and 32 years old were 11 77% and 11 59% and in Luochuan plots with those of 15 and 28 years old, 11 7% and 11 59% respectively. They are closing to 9 0% of wilting moisture of Changwu soil and 8 6% of wilting moisture of Luochuan soil. The pathway of rainfall percolating to groundwater was shut down by dry soil profile.
    References | Related Articles | Metrics
    Theory and Practice on Database of Three-dimensional Vegetation Quantity
    ZHOU Jian hua
    2001, 56 (1):  14-23.  doi: 10.11821/xb200101003
    Abstract ( )   PDF (266KB) ( )   Save
    The difference in spatial structure of urban greenery affects the environmental quality to a great extent. Taking the ability of absorbing CO2 and producing O 2 as an example, the volume the forest produce is about five times as much as that produced by grass of the same size. It can be inferred that the methods of relative analysis often used are not very accurate in some sense. The three dimentional vegetation quantity (hereinafter referred to as “3 D VQ”) is a new concept put forward by the author. The 3 D VQ means the volume of a space occupied by stem and leaves of a plant. Compared with those values concerning plane, the greenery value is the index that demonstrates the differences of urban greenery in spatial organization better. Therefore, it can be applied to calculate the theoretical value of environmental benefit in terms of greenery more accurately. After several years’ research, a series of theories and techniques have been made out. Several major breakthroughs are described as follows: 1. In terms of the method of simulating the stereo quantity by the plane quantity, the remote sensing models of measuring and calculating the 3 D VQ were put forward. With them we surveyed and calculated the 3 D VQ through interpretation of color infrared aerial photos and simulation technology of computer. Especially the “Logistic curve” equation was successfully corrected; as a result, the precision of calculating the 3 D VQ has remarkably been improved. 2. The first database of 3 D VQ has been established. There are several advances in the studies of the theories and techniques of establishing data model and structure and arranging and coding files and data. 3. The 3 D VQ database has been developed into an advanced management system in the general form of GIS. This system has the functions of inquiry, statistics, amendment, charting and establishment of new 3 D VQ database with the basic characters of spatially locating and window appearing. The system can directly serve the consumers of garden department as a macro managemental system for the whole city. It gives a lot of help to make a scientific and automatic management of gardens. It has also provided theoretical and techological basis for some relative analyses between urban greenery and environment for other relative studies.
    References | Related Articles | Metrics
    Demarcation of the Eco-geographical System Based upon the Extension Engineering Method——Taking Semi arid and Sub humid Areas in Mid temperate as an Example
    ZHANG Jun tao, LI Zhe, ZHENG Du
    2001, 56 (1):  24-31.  doi: 10.11821/xb200101004
    Abstract ( )   PDF (229KB) ( )   Save
    The extension engineering method introduces a matter element model, which consists of the matter, character and quantity. Formed as a three matter set, it can be expressed as R =(matter, character, quantity)=( N, c, c (N)) . Since the extension engineering method aims to turn the qualitative analysis concerning yes or no into the quantitative one, a new approach to the distinction and judgement has been developed. This paper presents a preliminary study on the demarcation of the eco geographical regional system based upon the matter element model. Through physio geographical analysis, documents and field investigations, combining the integrated analysis, dominant factors and expert integration, 40 typical sites were selected in the study area. Meanwhile, 4 indicators, i.e. the aridity index, growing season aridity index, profit and loss of soil moisture in growing season and the annual precipitation were also selected to reflect the moisture regime. In view of the identical variation of crop water demands and the profits and losses of soil moisture, in calculation, the profit and loss of soil moisture for maize was chosen as a representative indicator. By determining the classical scope, extensional scope, and the matter elements to be identified, a single index associated function and the multiple index comprehensive associated function were calculated. Based upon this as well as vegetation and soil types, the boundary between semi arid and sub humid areas of mid temperate zone in China was demarcated. In this study, not only the qualitative boundary between the above said, but also the boundary between the arid region in sub humid area and the humid region in semi arid area were proposed, which can reflect the transition of geographic boundary more objectively than before. The extension engineering method has an advantage of either rationally explaining the physio geographic demarcation or avoiding the drawbacks of single index and qualitative analysis of the former regionalization. It therefore, puts forward a new method for the establishment of the eco geographical regional system of China.
    References | Related Articles | Metrics
    Effect of Wetland Landscape Pattern on Nutrient Reduction in the Liaohe Delta
    LI Xiu zhen, XIAO Du ning, HU Yuan man, WANG Xian li
    2001, 56 (1):  32-43.  doi: 10.11821/xb200101005
    Abstract ( )   PDF (506KB) ( )   Save
    The effect of spatial pattern on the nutrient reduction is investigated based on the spatial simulation model designed for the estuary wetland of Liaohe Delta. Four scenarios are designed to test the effect of different landscape patterns on the nutrient reduction in the reed marsh: canal density, reed area size, reed area shrinking pattern, and pumping station position. According to the simulation result, each factor brings less than 10% change in the total nutrient reduction rate. More canals will not help much to improve nutrient reduction. Smaller areas are more efficient than larger ones. The shrinkage pattern is better than other shrinking patterns in keeping a higher nutrient reduction rate. It is also more efficient to keep the pumping station near the border of the area to be irrigated. These conclusions provide theoretical supports to strategy makers for local land use planning, and contribute to the understanding of the relationship between landscape patterns and functions.
    Related Articles | Metrics
    The Content of Soil Organic Carbon and Total Nitrogen and Correl Ativity between Their Content and Fluxes of CO22O and CH4 in Xilin River Basin Steppe
    GENG Yuan bo, ZHANG Shen, DONG Yun she, MENG Wei qi, QI Yu chun, CHEN Zuo zhong, WANG Yan fen
    2001, 56 (1):  44-53.  doi: 10.11821/xb200101006
    Abstract ( )   PDF (449KB) ( )   Save
    In the paper, the content characteristics of soil organic carbon and total nitrogen were studied, and correlativity between the content of soil organic carbon and total nitrogen and the fluxes of greenhouse gases CO2, N2O and CH4 were analyzed. All the samples were taken from temperate steppe of Xilin River Basin in Inner Mongolia of China. The results showed that the content of organic carbon range in soil surface layer (0~20 cm) decreased successively from 2 38% to 1 23% and the content of total nitrogen from 0 218% to 0 136% along the precipitation gradient from 470 mm to 150 mm. The contents of the soil organic carbon and total nitrogen had the decreasing trend due to grazing and cultivation. The fluxes of CO2 were significantly positively correlated with the content of the soil organic carbon, the content of soil total nitrogen, C/N ratio and the fluxes of N2O. The fluxes of N2O were significantly positively correlated with the content of the soil organic carbon, soil C/N ratio soil and the fluxes of CO2. The fluxes of both CO2 and N2O had the successively decreasing trend along the precipitation gradient. The fluxes of CH4 had no significant correlativity with the content of soil organic carbon, the content of soil total nitrogen, C/N ratio in soil, the fluxes of CO2 and the fluxes of N2O.
    Related Articles | Metrics
    Comprehensive Evaluation of Guangzhou Urban Sustainable Development
    XU Xue qiang, ZHANG Jun jun
    2001, 56 (1):  54-63.  doi: 10.11821/xb200101007
    Abstract ( )   PDF (154KB) ( )   Save
    With unfolding and deepening of the studies on urban sustainable development in the world, the reseach on comprehensive evaluation of urban sustainable development has also been carried out gradually. Guangzhou has acquired enormous achievements since the reform and opening up in 1978. On the one hand, urban economies have rapidly developed, where as on the other, urban environmental quality has declined, and social development lagged relatively. Firstly, aiming at the disunified dimensions of all kinds of indicators in the indicator system, the paper makes a standard treatment by the subjection function. Secondly, owing to the artificially selected reason, aiming at the overlap information which are included in all kinds of indicators, the paper eliminates the overlap information by the principal component analysis, and gets scores of SENI (sustainable environmental index), SECI (sustainable economic index), SSOI (sustainable social index) and cumulatives of principal components, and then calculates SENI, SECI and SSOI by add weigh models. Lastly, on the basis of SENI, SECI and SSOI, the paper designs 3 indexes reflecting the connotation of urban sustainable development, which are Level Index ( LI ), Development Index ( DI ) and Coordination Index ( CI ), and scale development levels, development rates and development coordination condition of urban sustainable development respectively. On the basis of environmental and socio economic development data from 1980 to 1996, the paper makes a comprehensive evaluation of urban sustainable development. The results are: as far as LI’s concerned, there are several characteristics on urban sustainable development in Guangzhou city: ① The stage of urban sustainable development is turning into high grade stage, including slow development stage (1980~1984), recessionary development stage (1984~1987), adjustable development stage (1987~1991), fast development stage (1991~1994) and slow development stage (1994~1996), which is accorded with the law of period in evolution and period between promotion of urban sustainable development. ② The change of urban environmental, economic and social development is dissynchronous. The relation of environment and economy puts up: when economy develops at high speed, there would be a serious environmental phenomena; when government strengthens the adjustment, a promising environmental phenomenon would occur. On the whole the relation of environment and economy is negatively related. The relation of environment and society is not taken on relativity as a whole. The relation of economy and society is taken on positive relativity, and indicates economic growth can drive social progress. At the same time, the paper raises the rate of social progress is much lower than the rate of economic growth, and in a sense the lag of social development will limit economic growth in the future. As far as DI’s concerned, urban sustainable development in Guangzhou city is taken on several characteristics: ① Environmental subsystem is taken on no sustainable feature; ② economic subsystem is taken on sustainable feature; ③ social subsystem is taken on sustainable feature; and ④ urban development is taken on sustainable as a whole because of pull effects of socio economic subsystem. As far as CI’s concerned, urban development is taken on weak sustainability, that is to say that urban environment and socio economic development are in harmonious. In a word, by the above mentioned comprehensive evaluation, the paper raises economic development there is at the expanse of serious environmental phenomena in the initial and middle stages of the reform and opening up in China, which counteract economic growth. It also raises there is non sustainable style of urban development, which cannot bring into urban development as a whole.
    Related Articles | Metrics
    Urban Image Space and Main Factors in Beijing
    GU Chao lin, SONG Guo chen
    2001, 56 (1):  64-74.  doi: 10.11821/xb200101008
    Abstract ( )   PDF (192KB) ( )   Save
    This article analyzes urban images held by people living in Beijing after a short review of theoretical development in urban image space studies. Two basic methods were used to obtain data, one is cognitive mapping and the other is photo recognition. Five major factors that may influence the designative image are examined one by one. Hence we conclude that the frame constituted by roads, landmarks, nodes and function areas consist of the major public imaginary of Beijing. The Second Ring Road separates the “inner city area” from the “outer city area” and the quality of urban image is quite different in area from one part to the others. Based on the above conclusions and findings, some useful suggestions are made for urban planning and designing of Beijing.
    Related Articles | Metrics
    Influence of Zaling and Eling Lake on the Annual Discharge of the Huanghe River Source Area
    LI Wang shou, FENG ling, SUN Sheng li
    2001, 56 (1):  75-82.  doi: 10.11821/xb200101009
    Abstract ( )   PDF (241KB) ( )   Save
    ZalingLake and Eling Lake, the two major lakes in the Huanghe River source area, effectively serve as reservoirs that lag the flood peak and regulate the annual discharge budget. Based on hydrologic data from the four control stations-Huangheyan, Jimai, Tangnaihai, and Xunhua, analysis are made according to the characteristics of the annual discharge spatial distribution to give the influence of these two lakes on the annual discharge in the Huanghe River source. First, Zaling and Eling Lake average the annual discharge budget due to their large capacity to hold water. second, in the low water years, the less discharge into the two Lakes combined with stronger surface evaporation lead to less annual discharge measured at Huangheyan station, which contributes to increase the annual discharge variation and aggravates the dryness. Third, based on comparing and analyzing the degree of water sufficiency at Huangheyan and downstream Jimai station, we find that Zaling and Eling Lake don’t significautly change the annual discharge measured at Huangheyan station, neither in abundant water years nor in insufficient one. These two Lakes are actually annual regulating lakes rather than multiannual ones.
    Related Articles | Metrics
    Formation and Growth of High Megadunes in Badain Jaran Desert
    YAN Man cun, WANG Guang qian, LI Bao sheng, DONG Guang rong
    2001, 56 (1):  83-91.  doi: 10.11821/xb200101010
    Abstract ( )   PDF (268KB) ( )   Save
    High megadunes in the Badain Jaran desert, with a height ranging from 200 to 300 m in general and maximum height of 500 m or more are seldom seen in the other sand seas of the world. Up to present no much work associated with the formation and growth of high megadunes have been done. On the spot investigations of the Badain Jaran desert and a series of research work, including sand dune types and their spatial features, megadunes strata and TL dating, palaeowind direction measurement and modern wind data analysis, indicate that the formation and growth of high megadunes in the Badain Jaran desert are controlled by sand source, prevailing wind patterns, underlying relief of megadunes and vegetation on sand dunes. Ruoshui system developed in the western and northwestern Badain Jaran area was a main sand source for the formation and growth of high megadunes. Dips from fossil sand dunes cross bedding and steep face orientations in three locaties distributed in the Badain Jaran desert demonstrate that the prevailing palaeowind patterns over the Badain Jaran desert are at variance throughout the Quaternary period. Before last glaciations westerly winds originating from westerly circulation predominated but that there were also important northwestly winds from East Asian monsoon circulation at the time of high megadune growth. Since last glaciations, northwestly winds have dominated the area but accompanied also with the relatively important westerly winds in the processes of megadune growth. Simultaneously, the initial stages of the magedunes are related to the wave like airflow motion caused by the intimidation from underlying hilly relief which become an obstacle against moving wind blown sand. The shrub and grass on sand dunes, fed by rainfall during stronger summer monsoon, encourages the growth and development of megadunes by trapping and accumulating upwind windblown sand and combating wind erosion as well as promoting roughness over dune surface. Intergrated aeolian bedforms in the area went through a temporal development process from barchans, barchanic ridges, compound barchans, megabarchans to high megadunes since the Quaternary.
    Related Articles | Metrics
    Processes of Gully Erosion and Accumulation in the Central Loess Plateau of China Since the Last Interglacial
    DENG Cheng long, YUAN Bao yin
    2001, 56 (1):  92-98.  doi: 10.11821/xb200101011
    Abstract ( )   PDF (227KB) ( )   Save
    A model was proposed for illustrating gully erosion accumulation processes since the last interglacial. According to this model, the erosion modules and accumulation rates of several erosion and/or accumulation stages for a typical small watershed in the central Loess Plateau of China were quantitatively calculated. Our calculations show that the erosion modules in the selected small watershed have values of 2 126 t/km2穉 during the marine isotope stage 5 (MIS5, 127~73 ka BP) and 972 t/km2穉 during MIS3 (62~26 ka BP), respectively, which are much less than modern erosion module with a value of about 5 000 t/km2穉 in the studied area. The increase of modern erosion module seems to suggest that loess erosion in the central Loess Plateau of China tends to be accelerated presently. Furthermore, gully erosion mainly occurred in the warm and humid interglacial periods, being dominant contributions to the total erosion. During the cold and dry glacial periods, gully development became evidently slowed down or was suspended, and loess deposits accumulated on the gully slope. Our results also demonstrate that gully evolution in the Chinese Loess Plateau is closely linked to paleoclimatic variations, and further indicate that abundant rainfall in the region of the plateau may give rise to occurrence of sediment hazards in the lower Huanghe River.
    Related Articles | Metrics
    Areal Diffusion and Integration of the Frontier Pioneering Culture in Hainan Island
    ZHU Hong, SITU Shang ji
    2001, 56 (1):  99-106.  doi: 10.11821/xb200101012
    Abstract ( )   PDF (294KB) ( )   Save
    The paper points out that Hainan culture is a kind of frontier pioneering culture, and focuses on its areal diffusion and cultural integration. Frontier pioneering culture is a new form of culture which springs up in pace with the exploitation of frontier areas through joint efforts of dismissed government officials and garrison troops historically and by means of land reclamation in modern times. There are differences between Hainan Island and the mainland in the course of cultural diffusion. In mainland, culture is diffused along the rivers or the plains whereas in Hainan Island altitude is the most important factor that influences the diffusion of culture. Because of cultural dissemination and diffusion, different cultures assimilate, blend or even merge into an organic one, which were called cultural integration or cultural synthesis. The formation of Hainan culture resulted in the integration of various kinds of frontier pioneering cultures in Hainan Island in the long span of history. In other words, Hainan culture is the synthetic outcome of the complicated integration process of national cultures of Han, Miao and Hui nationalities and modern cultures, such as the cultures of overseas Chinese, culture of land reclamation and cultivation, the western cultures based on the background culture of Li nationality. This is the new form of Island culture that developed in Hainan’s environment.
    Related Articles | Metrics
    Standardized Documentation of Models for Resources and Environment and Their Integration with GIS
    YUE Tian xiang
    2001, 56 (1):  107-112.  doi: 10.11821/xb200101013
    Abstract ( )   PDF (149KB) ( )   Save
    On the basis of analyzing and summarizing the research achievements on mathematical models for resources and environment, a framework of standardized documentation of models for resources and environment is proposed. It includes 6 message layers: (1) registration layer provides messages such as abstract of each model, contact address of author or authors and references; (2) technique layer provides messages such as mathematical equation or equations, parameter or parameters, variable or variables, hypothesis or hypotheses and background of resources and environment; (3) mathematical layer provides messages on mathematical foundation of each model; (4) process layer provides messages on construction process or deduction process of each model; (5) program layer provides messages on computer programming of each model; and (6) case study layer provides messages on application case studies of each model. Efficiently integrating mathematical models with GIS is the key technical issue of applying the standardized documentation of models for resources and environment to modelling sustainable development. Methods of integrating mathematical models with GIS can be classified into 4 types: (1) inserting the GIS functions into the software package of mathematical models requires programming in large amounts, which is the disadvantage of this method; (2) inserting mathematical models into GIS absorbs all advantages of existing GIS, but the used models are too simple; (3) coupling mathematical models with GIS loosely includes a standardized GIS software package and a computer program of a mathematical model, of which the disadvantage is that the data exchange is conducted between several different software packages and there is no common interface of users; and (4) coupling mathematical models with GIS closely couples several models with a GIS software package by programming or a macroinstruction. The integration methods of mathematical models with GIS mentioned above could not meet the requirement of constructing the system for modelling sustainable development. They need programming in large amounts, exchanging data between several different softeware packages, or macroinstructions. Our study is to develop an efficient integration method on the basis of the research achivements of Open GIS, by which the operated results of a mathematical model can be displayed on a visual interface supplied for modelers by GIS so long as the mathematical model is written in a common user interface. Finally, a framework of applying the standardized documentation of models for resources and environment to modelling sustainable development is proposed that includes 5 cross functional layers: (1) Geo Information system is to collect and collate information from typical previous case analyses, statistical data, environmental monitoring, remote sensing observation, investigation on the spot and research achievements, and to provide data input, storage, manipulation, analysis, and display capacities for geographical, cultural, political, environmental and statistical data in a common spatial framework; (2) Models for sustainable regional development are to simulate life support system, development support system, environment support system, society support system and intelligence support system of land use and their mutual relations by operating relative models from the standardized documentation of models for resources and environment; (3) Scenarios are to describe the current situation and alternative futures as well as possible ways from the present situation to the alternative futures by establishing the sign map and the diagnosis map; (4) Strategy formulation is to develop an overall approach to achieving its mission and objectives by establishing the action map, in which decision making programs are reasoned by changing various boundary conditions; (5) Strategy implementation is to put the strategy into action through establishing short term objectives, formulating policies, and matching structure with strategy.
    Related Articles | Metrics
Share: