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    15 July 2000, Volume 55 Issue 4 Previous Issue    Next Issue
    Assessment of Vulnerable Scope to Environmental Change in Jiangsu Coastal Plain
    YANG Gui shan, SHI Ya feng, ZHANG Chen, LIANG Hai tang
    2000, 55 (4):  385-394.  doi: 10.11821/xb200004001
    Abstract ( )   PDF (405KB) ( )   Save
    This paper develops the method of delimiting vulnerable scope and assessing coastal vulnerability through the observation and sampling in the field and applying the means of remote sensing and GIS, which can be suitable for great river delta and coastal plains with great area, relative complex micro geomorphology and the protection of seawall. The vulnerable scope should include inundated tidal flats due to sea level rise, coastal lowlands of soil salinization caused by rising phreatic water level and the area directly harmed by exacerbating storm surges due to sea level rise. The Jiangsu Coastal Plain is low flat, where considerable part of habitable lands are below local mean high tidal level (3 m above sea level) and depend on the protection of low standard seawall. So this area is the most vulnerable to sea level rise and exacerbating coastal hazards. Applying above mentioned method, the coastal vulnerability of Jiangsu Coastal Plain to relative sea level rise (approximately 50 cm up to 2050 yr) and exacerbating storm surge has been assessed. The results show that, up to the 2050 yr, the Jiangsu Coastal Plain will probably loss 12 8% of tidal flats (about 6.7?104hm2) and 7 7% of cultivated land (about 8 2 104 hm2). Meanwhile, 2 0% of population, 5 9% of original value of fixed capital, 4 1% of GDP (Gross Domestic Product), 53 3% of salt industry and 6 8% of aquiculture respectively will be affected, due to coastal environmental change. The coastal vulnerability degree(CVD) of the whole area belongs to medium grade (the index between 0 and 1 is 0 56). In view of different coast sections, CVD of the northern area of Guanhe River Mouth and Abandoned Huanghe River Delta belong to high grade (the indexes reach 0 81 and 0 63 respectively), these of the northern part of Middle Coastal Plain and the northern part of the Changjiang River Delta belong to medium grade too (the indexes are 0 45 and 0 46 respectively). that of the southern of Middle Coastal Plain belongs to the lowest grade (the index is 0 31).
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    Urban Land Use Change in Lhasa
    ZHANG Yi li, LI Xiu bin, FU Xiao feng, XIE Gao di, ZHENG Du
    2000, 55 (4):  395-406.  doi: 10.11821/xb200004002
    Abstract ( )   PDF (559KB) ( )   Save
    The urban development of Lhasa were studied mainly by analyzing the literatures, interpreting the aerial photograph (1970, 1985, 1986 and 1991), using contour maps (1965 and 1987), and overlaying them with GIS, investigating the spatial variation with GPS, conducting ecological and vegetation surveys. According to a complete field survey and visitation from the August to the October of 1999, the land use change in Lhasa in the past 50 years were listed as follows: 1. From 1951 to 1999, the Lhasa urban area expanded by 10.31 times and construction area by approximately 19 times. The spatial variation include: (a) In 1951, the city region of Lhasa was the region compassed by the Lhasa Circular Road, with an area of 3 3 km2, including the Potala Palace and true “Lhasa”, except for Norbu Ling. The shopping centers, palaces and temples had an area of 111 66 hm2. The housing area was only 22 hm2, and gardens and grasslands totaled 1700 hm2, and the fallow lands making up more than 45% of the total urban area. (b) The city had expanded by average 25 11 hm2 per year from 1952 to 1965. After 1959, the construction of roads in the center of the city and the urban expansion made this ancient city new. The urban area reached 6 82 km2. (c) From 1966 to 1989, the area of the urban region expanded by 96 88 hm2. From 1966 to 1970, the new urban area was concentrated in the western and eastern of Lhasa with a new area of 5 05 hm2 and 11 87 hm2 added to the original area, 3 59 times of that in 1951 and with an average rate of 101 09 hm2. The hydroelectric station, asphalt roads and some public facilities were built up in succession. From 1971 to 1986, Lhasa got a fast development, especially after 1980, an area of 62 000 m2 for housing was constructed around the Bakuo Street in which 43 000 m2 were increased. In the northern and western of Lhasa, new constructions were emerged. The urban area reached 26 89 km2, 8 14 times of that in 1951, with an average rate of 93 88 hm2 per year. From 1987 to 1989, the urban construction occupied 46 74 hm2 of farmlands, 39 61 hm2 of high quality grasslands and 180 83 hm2 not used land with vegetation, with an average rate of 10 6 hm2. (d) From 1990 to 1999, the constructions of Lhasa were concentrated in the center area and vicinity suburb with an area of 399 hm2 and an average rate of 39 9 hm2. From 1951 to the end of 1999, the construction of Lhasa occupied almost 32 94 km2, with an average rate of 68 63 hm2 per year. 2. Restricted by the geographical situation, the Lhasa City urban area was developed to the western along the Qinghai-Tibetan Road at the beginning, then expanded toward both sides of it, and then toward the north later. 3. The cultivated lands per capita in Chengguan District of Lhasa decrease sharply with 0 049 hm2 in the early 1999, accounting for 77 7% of that in 1964. For a long period, there has no centralized management of land use for Tibetan residents, plants and mining area. In 1985~1998, only urban fundamental construction occupied 284 68 hm2 of cultivated lands. The area of cultivated lands in Chengguan District has decreased by 645 73 hm2 in 27 years, making up 23 66% of the total lands and with an average rate of 23 92 hm2 per year, from2 729 47 hm2 at the end of 1971 to 2 083 74 hm2 at the beginning of 1999. The cultivated lands use change per capita in Chengguan District of Lhasa shows that it has decreased year after year, from the maximum of 0 086 98 hm2 in 1972, decreasing rapidly in 1988, to 0 0492 hm2 at the beginning of 1999, accounting for 77 7% of that in 1964 and 61 4% of that in the whole country (0 076 8 hm2).
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    A GIS based Model of Urban Land Use Growth in Beijing
    LIU Sheng he, WU Chuan jun, SHEN Hong quan
    2000, 55 (4):  407-416.  doi: 10.11821/xb200004003
    Abstract ( )   PDF (360KB) ( )   Save
    Based on the land use maps of Beijing in 1982, 1992 and 1997, its spatial and temporal process of urban land use growth was analyzed through spatial clustering and historical morphological approaches. The growth intensity index (GII), was employed instead of growth speed to describe the spatial differentiation of urban land use growth. Assisted by spatial analysis techniques of GIS, the average GIIs per year (AGIIPY) of 155 communes or towns during 1982~1992 and 1992~1997 were calculated and then classified through the Natural Breaks method, and the spatial differentiation maps of urban land use growth in Beijing during 1982~1992 and 1992~1997 were made. This paper found: (1) Industrial land is the most important element of urban land use growth in Beijing, and its contribution rate is on the increase, which is different from the general Western urban growth model driven by residential expansion. Since 1982, the industrial land had been keeping expanded at the average rate of 24~25 km2 per year. It is extraordinary high especially during the 1992~1997 period, while that of residential land and urban land use dropped by 59% and 24%, to 3 4 km2 per year and 29 8 km2 per year respectively. Thus, the contribution rate of industrial land to urban land use growth increased from 64 91% in 1982~1992 to 80 67% in 1992~1997. (2) The spatial pattern of urban land use growth in Beijing was in distinct concentric sprawl. With the growth centers’ gradual shift from the inner to outside, the new added urban land use were increased in distinct concentric zones and continually encroached upon the green spaces among the central mass and those “dispersed constellations”. The total area of green spaces for isolating built up areas in General Plan of Beijing, was 314 km2 in 1958, reduced to 260 km2 in 1983 and 160 km2 in 1993. The concentric sprawl pattern seriously destroyed the spatial structure of “dispersed constellations” designed by the General Plan of Beijing, and also badly worsened the regional ecological environment. (3) The growth axes of urban land use in the southern and eastern part of Beijing had stepped into their decline period. The southern and eastern part of Beijing is located in the North China Plain and have advantages in urban development space, economic and transport communication, etc., so that they are determined as the main urban development areas and direction by the latest General Plan (1991~2010). But this paper found, the two major growth axes of urban land use along the Beijing Tian Jin and Beijing Shen Zhen highways in the southern and eastern part of Beijing, had stepped into their decline period during 1992~1997. Their AGIIPY decreased from 1 63 and 1 58 during 1982~1992 to 0 86 and 0 67 respectively, and the spatial growth pattern have also switched from vigorous axial expansion to fill in among axes.
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    Geo-chemical Parameters of River Particulate in Eastern China
    CHEN Jing sheng, HONG Song, WANG Li xin, WANG Fei yue
    2000, 55 (4):  417-427.  doi: 10.11821/xb200004004
    Abstract ( )   PDF (534KB) ( )   Save
    A total of 42 geographically diverse particulate samples (including suspended matters and surface sediments) were collected from 19 major rivers in eastern China. The <63 μm size fractions were sieved for studies. The particulate samples were determined for selected geo chemical parameters, such as element composition, grain size distribution, clay mineral composition, TOC and humic substance components. 1. The contents of 16 elements (Al, Ca, Mg, K, Na, Ti, Fe, Mn, Cu, Pb, Zn, Cd, Cr, Co, Ni and V) in river particulate were measured. Their geographic variations were linked to the climatic features and geologic background in the river basins. 2. The grain size distribution of suspended matters has a less change range than that of surface sediments. The average grain size (M Z) of suspended matters was smaller. From north to south, the contents of Montmorillonite had a distinctive tread of decrease (62%~15%) and the contents of Kaolinite had a distinctive tread of increase (11%~55%). So the ratio of Montmorillonite/Kaolinite decrease gradually (3 88~5 27). The contents of TOC in particulate decrease from the Heilongjiang River (2 33% for surface sediments, 5 88% for suspended matters) to the Huanghe River (0 18% for surface sediments, 0 61% for suspended matters), then increase from the Huanghe River to the Zhujiang River (2 62% for surface sediments, 2 82% for suspended matters). The ratio of Humic acid to Fulvic acid from the north to the south decreases (1 03~5 38) except for the Huanghe River (0 18). pH(H2O) of surface sediments varies from 6 48 to 8 78, higher in North and Central China (8 39~5 78) and lower in rivers of East-North and South China (6.48~5.70). 3. Correlation analysis reveals that there are relatively strong interrelations among the contents of Cu, Pb, Zn, Cd, Cr, Co, V and most of the geo chemical properties of the particulate. The positive correlation between the contents of Cu, Pb, Zn, Cd, Cr, Co, V and the contents of Al oxides, and clays in the particulate is proved to be of extreme significance. Only the content of Ni shows no correlation with the geo chemical properties.
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    Spatiotemporal Variability of Soil Moisture in Small Catchment on Loess Plateau——Semivariograms
    WANG Jun, FU Bo jie, QIU Yang, CHEN Li ding
    2000, 55 (4):  428-438.  doi: 10.11821/xb200004005
    Abstract ( )   PDF (564KB) ( )   Save
    At present, using geostatistics for studying on these variables with random and structure is becoming one of the main spatial analytical methods within the field of environmental sciences. In hilly areas of Loess Plateau, due to the importance of soil moisture, many researchers have studied on its spatial variability and relationships between land use and topography using descriptive methods. However, studies on that the spatiotemporal variability of soil moisture using geostatistics are still inadequate in this area. In this paper, we use geostatistics combined with GIS to determine and quantify the spatial and temporal variability of soil moisture. The results indicated that soil moisture exhibited high fractal dimensions and clear spatial autocorrelation. For mean soil moisture of 0~50 cm, the seasonal changes of the sills were opposite to the mean soil moisture. During dry season, the spatial heterogeneity of soil moisture was high, and the sills showed high level. During wet and extremely conditionds, the sills decreased and were low. The ranges varying between 135 m and 160m were high during dry season and low during wet season. The nuggets, random variance, ranged from 0 2 to 1 5, and did not exhibit apparent seasonal pattern and loosely mimiced mean soil moisture. For profile soil moisture, the sills except for 5 cm increased with soil depth during whole observation period. The ranges varying between 60m and 160 m did not show the systemic change with depth. However, the ranges of soil moisture of 45 cm and 70 cm exhibited little fluctuation compared to 5 cm, 15 cm and 25 cm during study period. After a significant rain event, the changes of the sills and ranges with depth became more complicated. The nugget showed no clear pattern with depth, and tended to high value with high sill and low value with low sill. These suggest that the processes for influencing on profile soil moisture pattern were convoluted, and their relative roles were different during the observation period. The spatial dependence and seasonal variability of soil moisture were interpreted by land use, topography, precipitation and soil physical attributes. Their relative roles of influencing on soil moisture depended on different seasons.
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    An Experimental Study on Influence of Materiel Component to Non-linear Relation between Sediment Yield and Drainage Network Development
    JIN De sheng, CHEN Hao, GUO Qing wu
    2000, 55 (4):  439-448.  doi: 10.11821/xb200004006
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    In this paper an experimental study on influence of materiel component to non linear relation between sediment yield and drainage network development has been completed in the Lab of Fluvial Geomorphology in the Institute of Geography, Chinese Academy of Sciences. The area of flume drainage system is 81 2 m2, the longitudinal gradient and cross section slope are from 0 0348 to 0 0775 and from 0 0115 to 0 038, respectively. Different model materials with a medium diameter of 0 021 mm, 0 076 mm and 0 066 mm cover three experiments for each. At the beginning the ψ shaped small network is dug in the flume, an artificial rainfall equipment is a sprinkler system composed of 7 downward nozzles, distributed by hexagon type and a given rainfall intensity is 35 56 mm/hr·cm2. Three experiments are designed by process response principle. Running time spans are 720 minutes, 1 440 minutes and 540 minutes for Run Ⅳ, Ⅵ, and Ⅰ respectively.\;Three experiments show that the sediment yield processes are characterized by delaying with a vibration. During network development the energy of a drainage system is dissipated by two ways, of which one is increasing numbers of channel (rill and gully), and another one is enlarging the channel length. The fractal dimension of a drainage network is exactly an index of energy dissipation of a drainage morphological system. Change of this index with time is a unsymmetrical concave curve. Contracting three experiments explains that the vibration and the delaying ratio of sediment yield processes increase with material carousing, while the number of channel decrease. The length of channel enlarges with material fining. There exists non linear relationship between fractal dimension and sediment yield with an unsymmetrical hyperbolic curve. The absolute value of delaying ratio of the curve reduces with time running and material fining. It is characterized by substitution of situation to time.
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    Sediment Distribution and Transport Patterns in Jiaozhou Bay and Adjoining Areas
    WANG Ya ping, GAO Shu, JIA Jian jun
    2000, 55 (4):  449-458.  doi: 10.11821/xb200004007
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    Sediment characteristics are important for understanding of hydrodynamic processes and sedimentary environments. In the present study, 87 sediment samples were collected from Jiaozhou Bay and adjoining areas, Shandong Peninsula, China; 81 of the samples were analyzed using a Cilas 940L Laser Analyzer and by sieving (for particles with a diameter of <2 mm and >2 mm, respectively) to obtain grain size data. Three grain size parameters i.e. mean grain size ( μ ), sorting coefficient ( δ ) and skewness ( S k ) are then calculated by a moment method (McManus, 1988). The result shows that 9 types of sediment are present in Jiaozhou Bay and adjoining areas according to the sediment classification scheme proposed by Shepard (1954) and Blair McPherson (1999). The sediment distribution pattern is complex, indicating a multi source nature of sediment supply for the study area. Mean grain size and sorting coefficient for the sediment in Jiaozhou Bay is -0 4~7 5Φ and 1 2~4 3, respectively. The coarse (i.e. μ <0 65Φ) and well sorted (i.e. δ <2) sediment is located over the central and southwestern parts of the bay, where the sediment is negatively skewed, with a minimum S k value of -3 8. The sediment at the mouth of Jiaozhou Bay is the coarsest ( μ =-0 4Φ) and positively skewed ( S k =3 3). Good correlation between the distribution pattern of the grain size parameters in Jiaozhou Bay and the sediment types (and hydrodynamics processes) is present. The two dimensional models for grain size trend analysis proposed by Gao and Collins (1992) are adopted to identify sediment transport pathways in the study area. This method is on the basis of the assumption that in the direction of transport the sediment becomes either better sorted, finer in grain size and more negatively skewed, or better sorted, coarser in grain size and more positively skewed. Further, in order to use this model for the grain size trend analysis to deal with the situation that the sampling sites are not evenly distributed over the study area, the area is divided into 4 subareas. For each of the sub-areas, different characteristic spatial sampling intervals are adopted. Grain size trends are then obtained by using this model, with the “edge effect” being removed. The net sediment transport pathways in Jiaozhou Bay and adjoining areas thus derived show that sediment is transported towards the central sand bank within the bay and the seaward end of the deep channel at the mouth of the bay. Such patterns are highly consistent with those of current velocities, geomorphologic information and heavy mineral movement. Therefore, the grain size trend model is applicable for coastal areas with complicated sediment distribution patterns and irregular sediment sampling grids.
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    Th Rate of Environmental Degradation and Natural Rehabilitation in Typical Karst Area of Guizhou
    YANG Sheng tian, ZHU Qi jiang
    2000, 55 (4):  459-466.  doi: 10.11821/xb200004008
    Abstract ( )   PDF (271KB) ( )   Save
    The land cover, vegetation cover, biological product, biological delivery and soil physical chemical features were regarded as indexes mainly representing Karst environment degradation and its rehabilitation, and remote sensing and survey are used to study them. A study area was in Zhiyun district, Guizhou Province. The study method is as follows: (1) The imageries of Landsat MSS in 1973, TM in 1990 and TM in 1995 were chosen to classify the land cover. (2) The TM imageries data, which were obtained at the same time at the end of October in 1994 and 1995, were chosen to calculate their NDVI (Normalized Difference Vegetation Index. Its formulation is (TM 4-TM 3)/(TM 4+TM 3)). (3) According to the degradation, the sample plots were chosen. The plot of forest is 25 m2, the shrub is 5 m2 and the grass is 1 m2. The production and the number of vegetation were surveyed at four corners and in the middle which is 1 m2 to forest and shrub. To grass, all in the plot were surveyed. (4) In the same plot of vegetation survey, the soil samples were analyzed in the experiment. The analysis led to the following conclusions: (1) After analyzing the complex Karst environment, the three aspects of land cover, the vegetation and soil are chosen to reflect the degradation and natural rehabilitation of Karst area. (2) Because of human activities, the area showing vegetation degradation is estimated to be 1 63%. The impact of human exploitation makes the degradation rate of vegetation cover reach 1 88%. (3) The area of the forest and shrub cover is the main object for human cultivation due to its environmental quality. Therefore policies on environmental conservation are recently executed and the degradation rate has been dropped by 1 9%, but estimation shows that there is still 0 48% of the forest and shrub degraded per year. (4) When vegetation becomes shrub from grass, the increasing rate of vegetation delivery is three times per year until vegetation is rehabilitated to forest. The annual rate of vegetation turned from grass to shrub reaches 2 5% and the rate of vegetation cover from shrub to forest reaches 3 5% until vegetation becomes forest. The annual rate of vegetation production from shrub to forest reaches 50% until forest appears. Lastly, the soil becomes fertile during natural rehabilitation, the annual rate of soil organic constituent turned from grass to shrub is 1 5% and the rate from shrub to forest is 2 5%.
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    The Cartographic Method of Synthetic Assessment for Eco-environment in Hainan
    HU Meng chun, MA Rong hua, WU Huan zhong
    2000, 55 (4):  467-474.  doi: 10.11821/xb200004009
    Abstract ( )   PDF (360KB) ( )   Save
    RS is at present the primary and effective means to measure ecological situation. GIS provides an efficient tool to analyze the status and the changes of eco environment. In this study, we introduce how to draw up the assessment map eco environment based on RS and GIS with the theory of eco landscape as a guidance, which takes the integrated assessment of the multi factors as a major method. Firstly, we overlap the topography, soil and vegetation types based on the vegetation type spot and divide it into different eco landscape types which are considered as the basic unit of cartography for assessing eco environment. Secondly, we put the TM Landsat data and others such as DEM into ERDAS to classify them with maximum likelihood supervised classification, and verify the supervised classification results by visual interpretation to extract the thematic information. Then, the topographic map, soil map and vegetation types map are made with ARC/INFO. Finally, we build the assessment index system of eco landscape factors and have the index value processed normalization to calculate the single factor assessment index and make the single factor assessment maps. Then, we overlap the single factor assessment maps to get the synthetic assessment map by ARC/INFO spatial overlapping analysis. During the overlapping, the single factor assessment indexes are processed with weight function to get the synthetic assessment index, then the eco landscape type units are assigned. According to the method mentioned above, the eco landscape type units are evaluated one by one. The eco environment assessment map of Hainan Island made by the method mentioned above shows that the eco environmental quality gradually declines from the central to the peripheral. And there are four counties in the ideal state, another four ones in the state of kilter, and the remaining in the relatively poor state. We can dynamically inspect and effectively predict the eco environmental change with the dynamic serial maps of the regional eco environment made by the method mentioned above.
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    Functional Features and Spatial Structure of CBDs in Guangzhou
    YAN Xiao pei, ZHOU Chun shan, LENG Yong, CHEN Hao guang
    2000, 55 (4):  475-486.  doi: 10.11821/xb200004010
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    This paper, on the basis of literature review on CBD research results, studies the functional features and spatial structure of CBDs in Guangzhou, a metropolis of South China, in terms of documents, data and on the spot investigation. The attention is initially paid to the delimitation of CBD. A comprehensive method of delimiting CBD is invested from the major characters of CBD dividing the streets with high land value according to the basic land value of Guangzhou, determining the transport circle surrounding the districts with high land value and further determining the limits of CBD, and investigating some typical streets in the delimited CBD by the index of Murphy and Vance so as to examine the feasibility of the delimitation. In terms of the comprehensive method, the CBD of Guangzhou is divided into three sub districts including one traditional and two new CBD sub districts. Then the functional features including the overall and sub-district features of CBD are analyzed. Some indicators, such as location quotient, office floor area, vacant office floor rate, establishments and employment of central functions, offices of non Guangzhou enterprises, offices of transnational enterprises and transnational financial organs, are used to reflect the overall features of centralization and overseas orientation. The comparative analysis on the central, external and dwelling functions of the three CBD sub districts reveals that the traditional CBD is dominated by retail but the new CBDs by enterprise offices, finance and insurance, and information consultation. These two types of functions represent different stages of CBD development and reflect the evolution of CBD function. Thirdly, the spatial structure of CBD and its formation mechanism are examined. The research results reveal that the CBD of Guangzhou shows a ‘separation’ structure with time, characterized by the spatial subdivision and agglomeration of various functions. From the horizontal structure of CBD sub districts, based on the analysis of land value and function, the traditional CBD shows a ‘twin core ring’ structure, i.e. land use changes regularly with the distance from the peak land value intersection, but the new CBDs show a ‘linear’ structure, i.e. the central functions distribute along the major streets. From the vertical structure of CBD sub districts, based on the analysis of the on the spot investigation, the three sub districts differ in vertical changes of building height and floor function. Furthermore, the formation mechanism of CBD spatial structure, in the aspects of CBD function demand, rent bid relation, environment, technology and behavior, are analyzed. Finally, a brief conclusion is drawn and a discussion on the general evolution model of CBD function and spatial structure of Guangzhou and further Chinese metropolises is made.
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    Isotope Tracer on Water Cycly System in Jiuzaigou, Sichuan
    YIN Guan, FAN Xiao, GUO Jian qiang, YANG Jun yi
    2000, 55 (4):  487-494.  doi: 10.11821/xb200004011
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    Use of isotope tracer technique of natural water can effectively trace water origin and transportation process, and reveal recharge and discharge relationship of various water bodies and hydraulic connection of various hydrogeologic units. It has important application values and is of scientific significance for protecting and developing the precious natural resources, and provides reference for the similar researches. The following results have been obtained in this research: (1) There is hydraulic connection between Zhanghai and the middle course of Rizegou. The water in Zhanghai leaks at Jianzhuhai-Tianehai area in Rizegou along the karst passages with the fault zones. The leakage water in the rainy season accounted for 21% of the total runoff volume in Jianzhuhai, and about 28% in the dry season. The absolute leakage water volume was stable and almost no change occurred with changes in seasons. (2) There are independent karst passages and groundwater reservoirs in areas from Wuhuahai to the middle upper courses of Zangmalongli in Rizegou. The rain water in the middle upper courses of Zangmalongli during the rainy season drained off through the independent karst passages. The outlets are located in areas between Wuhuahai and Xiongmaohai. The amount of water discharged into Wuhuahai accounted for about 30%. In the dry season the amount of water drained off into Wuhuahai in the same form dropped to the lowest point, but did not cause obvious influence on the amount of water in Wuhuahai. (3) Based on the runoff isotope composition features of Zhanghai and Rizegou, only part of the runoff in the highest concation of Zezhawagou source recharged into the downstream of Zhanghai, and the other part fell down to discharge into Zangmalongli valley of Rizegou source through the well developed karst passages along the NW fault zone. This is one of the important reasons accountable for the abundant runoff in Rizegou all the year round. (4) There is no direct hydaulic connection between Danzugou and Wuhuahai, and the water over the dry valley fell down to discharge through the subterranean karst passages, and the discharged mouth is at the downstream area in Wuhuahai.
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    Environmental and Ecological Water Consumption of River Systems in Haihe-Luanhe Basins
    LI Li juan, ZHENG Hong xing
    2000, 55 (4):  495-500.  doi: 10.11821/xb200004012
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    In the history of water utilization and development, our attention has always been paid on the benefit we could get from rivers while environmental and ecological function of the river system used to be neglected. Thus the activities of water utilization and development were accompanied by more and more serious environmental and ecological problems. In order to reduce the environmental and ecological problems induced by water resources development and utilization, this paper has proposed a concept of environmental and ecological water consumption. In general, we defined that the environmental and ecological water consumption means the minimum water that must be saved in or consumed by the natural water bodies to conserve their environmental and ecological functions. Based on the definition, the methods on calculating the amount of environmental and ecological water consumption are determined. Water consumption can be divided into three parts, i.e. the basic water consumption of rivers, water consumption for transportation of sediments and salts, water consumption for evaporation of the lakes. The methods for calculating the different parts of water consumption were shown in expressions. In a case study on Hai Luanhe Basins, the hydrological records before 1960, which may represent the natural conditions of the river systems, were used for calculating. The results of the calculation have shown that the environmental and ecological water consumption in the Basins is about 124?10 8m3, including 57?10 8m3 for basic consumption, 63?10 8m3 for transportation of sediments and salts and 4?10 8m3 for net evaporation loss of lakes. Thus it was estimated that the total amount of environmental and ecological water consumption accounts 54% of the total amount of runoff (228?10 8m3). However, there are still some aspects of environmental and ecological consumption that are not under our consideration. It should be realized that the required amount of environmental and ecological water consumption must be more than that we have calculated. According to this result, if the rational utilization rate of the runoff in the basins is more than 40%, the problems of eco environment will be serious but the current utilization rate of the Basins is as high as 80%. It is on the urgency to control and adjust water development and utilization to eliminate those problems existed and to avoid the potential ecological or environmental crises that are still not clear.
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    Features of Two Warming Periods and their Causes in Shanghai for the Last 127 Years
    XU Jia liang
    2000, 55 (4):  501-506.  doi: 10.11821/xb200004013
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    Based on the observational data of meteorology from 1873~1999 in Shanghai and its suburbs from 1961~1999, after minimizing the possible biases against climate change caused by urban heat island, this paper mainly discussed the different structure distribution of temperature in two warming periods in Shanghai during the last 127 years. Then the reasons for the different structure distribution are diagnosed. The results obtained are as follows: (1) The variation of annual mean temperature in Shanghai during the last 127 years has gone through two obvious warming periods. They took place from the mid 1930s to the early 1950s and the mid 1980s to nowadays. (2) The difference of temperature structure is obvious, but the warming rates are very close during two warming periods. During the first period, the warming mainly occurred in daytime and maximum temperature was higher than the average year markedly, but minimum temperature was not obvious. These changes were remarkable in summer. During the second period, the warming took place in nighttime, minimum temperature had the most significant warming trend and maximum temperature dropped. The phenomenon is also obvious in summer. Compared with the former, daily temperature range has a decreasing trend during the second warming period. (3) The correlation analysis showed that the difference of temperature structure in the two warming periods is mainly related to solar radiation and atmospheric water vapor content. During the last 41 years, the decrease of Shanghai’s direct solar radiation and global radiation and increase of diffused solar radiation are strongly correlated with the atmospheric pollution and atmospheric opacity. The increase of atmospheric water vapor content is depended on climate warming which is resulted from enhancement of greenhouse effect. (4) The cloud amount and daily temperature range in Shanghai are anti correlated to a correlated extent. Further study of the relationship will depend on the observation quality of cloud amount.
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