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    15 September 2001, Volume 56 Issue 5 Previous Issue    Next Issue
    Nitrogen Biogeochemical Cycling in the Changjiang Drainage Basin and its Effect on Changjiang River Dissolved Inorganic Nitrogen: Temporal Trend for the Period 1968~1997
    YAN Wei jin, ZHANG Shen, WANG Jia hui
    2001, 56 (5):  505-514.  doi: 10.11821/xb200105001
    Abstract ( )   PDF (230KB) ( )   Save
    In this paper, we present estimates of nitrogen (N) biogeochemical cycling in the Changjiang drainage basin, including N inputs, outputs and internal transfer for the period 1968 1997. The total N input, output and internal storage are approximately 10.0?10 9, 6.7?10 9, and 3.5?10 9 kg, respectively, in 1997, which is about fourfold, fivefold, and threefold of these in 1968, respectively. In terms of N inputs, N fixation was often a dominant input before 1977, providing about 1.0?10 9 kg year 1 ; while N fertilizer dominated N input after 1983, supplying an additional input of some 5.0?10 9 kg year 1 . In terms of N output, we estimate that the river dissolved inorganic nitrogen (DIN) concentration and flux have increased by about 10 fold from 1968 to 1997, reaching 1.60 mg L 1 and 1.40?10 9 kg, respectively, in 1997. Our study shows that about 25.0% of the total N input is transported through the river, while some 33% of the input is emitted by denitrification and volatilization, and the remaining 42% of the input is stored within the basin. The integrated N input, budget and storage have been linked to the increasing temporal trends of Changjiang River DIN. It is demonstrated that integrated N input, especially N fertilizer application, rather than human population density in the basin is the preferable predictor of the river DIN concentration and flux. Therefore, how N fertilizer is effectively applied is of crucial importance to the sustainable development of agriculture in the basin.
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    Chemical Element Transferring Features of Weathering Granite Regolith in Three Gorges Dam Region
    ZHANG Li ping, ZHU Da kui, YANG Da yuan
    2001, 56 (5):  515-522.  doi: 10.11821/xb200105002
    Abstract ( )   PDF (478KB) ( )   Save
    The exposure of river valley including riverbed as a result of clearing up sediment and regolith on the foundation of dam in the Three Gorges of the Yangtze River in 1999, river valley including riverbed was exposed which offered a good opportunity to research river valley landforms The chemical element transferring features in different valley landform positions are mainly researched in this paper 1 Sample collection:In lower 100 m of dam foundation, 50 samples were collected along NE42 ? trending cross section of river valley, at 3 different elevations (riverbed, flood plain, valley slope) and 6 typical columnar sections 2 Analysis:Based on the X rays fluorescent slice, weathering ratio, chemical element transferring ratio, the coefficient of average dripping and washing, the intensity of weathering were further calculated in detail 3 Conclusions:(1) In various landform positions of the river valley, the process of desilication is not distinct (2) In riverbed weathering granite regolith, easy soluble CaO and MgO are relatively concentrated on the contrary, Al 2O 3 shows a tendency to decrease The concentrated rate of Fe 2O 3 is the greatest in various landform positions of the river valley (3) In flood plain weathering granite regolith, K 2O and MgO contents are relatively concentrated (4) River valley slope weathering granite regolith is a typical northern subtropical weathering regolith, and its chemical weathering degree is in the transitional period from early phase to middle phase (5) In the upper middle layer of vertical columnar section in riverbed and valley slope weathering granite regolith, there is a concentrated layer of easy soluble elements and a leached layer of concentrated elements (6) Element transferring absolute intensity of riverbed weathering granite regolith is the greatest of three landform positions The order of element transferring relative intensity is flood plain weathering granite regolith > riverbed weathering granite regolith > valley slope weathering granite regolith The above mentioned conclusions indicated that, under certain climate conditions, chemical elements are transferred along with landform and water circulation in weathering granite regolith.
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    The Feature of Seasonal Frozen Soil in Qinghai Tibet Plateau
    WANG Cheng hai, DONG Wen jie, WEI Zhi gang
    2001, 56 (5):  523-531.  doi: 10.11821/xb200105003
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    The seasonal frozen soil in the Qinghai Tibet Plateau has strong response to climate change, and it effects the climate change at the same time. In this paper, the frozen soil maximum depth of 46 stations covering 1961~1999 in the Qinghai Tibet Plateau are analyzed by rotated experience orthogonality function (REOF). The results show that there are 4 main frozen anomaly regions in the Qinghai Tibet Plateau, i.e., northeast Qinghai Tibet Plateau, southeast plateau, south plateau and Qaidam Basin pattern. The frozen soil depth annual anomaly in the above representative areas shows different change trends. But the main trend, except for the Qaidam Basin, has been in decrease since the 1980s, which shows climate warming. On the average, the maximum soil depth has decreased by about 0.02, 0.05, 0.14 m over northeast, southeast and south of the Qinghai Tibet Plateau, but increased by about 0.57 m over the Qaidam basin during the 1990s. It shows different responses to the above areas in climate system and the Qinghai Tibet Plateau has dynamical effects on atmospheric circulation. The spectral analysis shows: there are different variance cycles in high frequency in four areas, i.e., there is a cycle of about 2 year length in the Qaidam Basin and south of Qinghai Tibet Plateau; there is a cycle of about 14 year length over all the four areas in lower frequency. It shows different soil texture and solutes over the four areas.
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    An Estimation of Wetland Vegetation Biomass in the Poyang Lake Using Landsat ETM Data
    LI Ren dong, LIU Ji yuan
    2001, 56 (5):  532-540.  doi: 10.11821/xb200105004
    Abstract ( )   PDF (265KB) ( )   Save
    The Poyang Lake is the largest freshwater lake in China with an area of about 3 000 km 2 This paper conducted a digital and rapid investigation of the lake’s wetland plant biomass using Landsat ETM data acquired on April 16,2000 First, using the false color composite derived from the ETM data as one of the main references, the authors planned a reasonable field sampling route for the biomass, and then carried out it during April 18 28,2000 Based on geometric correction of both the sampling data and the ETM data to an area equal projection of Albers, the linear relationships among the field biomass and some transformed data from the ETM data and the band 4 were calculated statistically The results show that the sampling data has the best positive correlation to the band 4 data with a coefficient of 0 86, followed by the DVI and NDVI data with coefficients of 0 83 and 0 80 respectively Therefore, a linear regression model established by using the field data and band 4 data was used to estimate the total biomass of the whole Poyang Lake, and to make the map of the biomass distribution It is shown that the remote sensing technology has many advantages over the traditionally used method engaged in the biomass investigation in a lake.
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    RS Research of Landscape Distribution Characteristics of Northern Piedmont, Tianshan Mountains
    CHENG Wei ming, ZHOU Cheng hu, TANG Qi cheng, YAO Yong hui, ZHANG Bai ping
    2001, 56 (5):  541-548.  doi: 10.11821/xb200105005
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    The northern piedmonts of the Tianshan Mountains are about 280 km long and 60 km wide, extending from Kuytun city to Fukang city, which are transitional belts between mountains and plains, appearing in three rows with different morphologies and with their age becoming younger from south to north Based on GIS and RS, and the materials of the former researchers, this paper deals with the genetics of the piedmont belts and their landscape features resulting from piedmont folding by neotectonic movements, and also describes their length, width and slope by remote sensing image interpretation The characteristics of the piedmont belts here are found to be very important for the surrounding environment by preventing underground water from flowing into plains, changing underground water, increasing the flux of surface flow water, in addition to its role in protecting the surrounding environment.
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    The Influential Factors and Spatial Distribution of Floating Population in China
    ZHU Chuan geng, GU Chao lin, MA Rong hua, ZHEN Feng, ZHANG Wei
    2001, 56 (5):  549-560.  doi: 10.11821/xb200105006
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    This paper makes a critical review about the researches on the floating population in China since the 1990s, then based on the floating population data in 1996 from the Ministry of Public Security of China, some influential factors and spatial distribution of floating population are analyzed. (1) By analyzing the factors, the authors find that two factors, i.e., economic growth and investment in city, are notably relative to the size of urban floating population. (2) By visualization technique of GIS and the integrated methods for spatial correlation analysis, the authors find that the spatial distribution of China’s floating population is of an evident urban rural duality with three clusters and five zones, which are the Eastern cluster, the Middle cluster, the Western cluster, the Beijing Tianjin zone, the Northeast zone, the Anhui Jiangxi zone, the Xinjiang zone and the Yunnan zone.
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    Evaluation on the Sustainable Development Capacity and Regularity of its Regional Differentiation in Hexi Region
    FANG Chuang lin, Yehua Dennis Wei
    2001, 56 (5):  561-569.  doi: 10.11821/xb200105007
    Abstract ( )   PDF (294KB) ( )   Save
    Hexi region is one of the development poles in the process of implementing the great development strategies of western China It is also one of the regions possessing most energetic and greatest potential in both today and future socio economic development in Gansu Province. According to AHP Model supported by entropy technology, the indicators’ weights of the sustainable development indicator system in Hexi region are worked out According to Multiple Hierarchies & Targets Fuzzy Comprehensive Measurement Model, the sustainable economic development capacity, the sustainable eco environmental development capacity and the sustainable social development capacity in Hexi region are all calculated, then the whole sustainable development capacity is worked out and the regional differentiation regularity of the sustainable development is summed up It is considered that the difference of the sustainable development capacity in each county in Hexi region is great while the regional differentiation of the sustainable development capacity is regular The change regularity of the sustainable development capacity goes as follows: it is higher in the upstreams while lower in the mid and down streams, higher in the industrial and mining area while lower in the farming area, higher in the pastoral area while lower in the farming area, higher in the urban area while lower in the farming area, and higher in the minority area while lower in the Han nationality area.
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    Development of Commodity Housing in Guangzhou and its Surrounding Areas
    YAN Xiao pei, ZHOU Chun shan, DENG Shi wen, CHEN Hao guang
    2001, 56 (5):  570-580.  doi: 10.11821/xb200105008
    Abstract ( )   PDF (429KB) ( )   Save
    This paper, based on survey and statistical data, focuses on the development and distribution of commodity housing in Guangzhou and its surrounding areas in the 1990s Firstly, the characteristics of commodity housing development were identified, e g the development capacity increased, development scale expanded, development types were diversified, but the problems like empty space and incomplete building were obvious Then the spatial distribution and sprawl of commodity housing were analyzed For the urban district, 1 149 pre sale permits, accounting for 71 6% of the total permits, were issued The total built up area was 28 072?10 3 m 2, accounting for 73 9% of the total The five commodity housing types were spatially recognized They were (1) multi story residential buildings oriented to domestic market; (2) high density developed high story residential and office buildings at large scale (built up area above 84?10 3 m 2); (3) residential buildings with shops at small scale(built up area less than 36?10 3 m 2); (4) villa oriented the overseas market at medium scale(built up area between 84?10 3 m 2 and 36?10 3 m 2); and (5) low density developed high story office buildings with shops at medium scale In the suburbs, 456 pre sale permits, accounting for 28 4% of the total permits, were issued The total built up area was 9 916?10 3 m 2, accounting for 26 1% of the total Three characteristics of the commodity housing distribution in the suburbs could be identified: (1) the commodity housing stretched northwards, eastwards and westwards along the external transport routes; (2) there were a lot of villa and multi story commodity buildings as compared with the urban districts; and (3) the spatial pattern of function combination of buildings was diversified Thirdly, the spatial development of commodity housing in the surrounding areas of the city was examined Several characteristics could be identified: the development scale was rapid and large, the residential housing was dominant, the market was mainly oriented to local people of Guangzhou The main factors for commodity housing development in the surrounding areas were the movement of Guangzhou people outwards due to the inner city redevelopment and comparative advantages of real estate development in the surrounding areas Fourthly, the impacts of commodity housing development on urban spatial structure were analyzed The development of commodity housing has expanded the built up area and increased the height of the city, has promoted the spatial transformation of the urban functions and formation of new urban center, and has caused the formation of the satellite town crossing administrative divisions But it has also caused some negative effects, such as the over expansion of the built up areas and urban environmental issues Finally, three implications should be further considered (1) vacant commodity housing will hinder further investment, production and consumption of the real estate; (2) the different commodity housing types mean that the factors influencing the social spatial structure of Guangzhou are changing.
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    Effects of China’s Opening up Policy on the Nation’s Regional Economic Development
    GUO Teng yun, LU Da dao, GAN Guo hui
    2001, 56 (5):  581-589.  doi: 10.11821/xb200105009
    Abstract ( )   PDF (352KB) ( )   Save
    China’s opening up policy has been significant, and boosted both its economic development of the coastal areas and inland areas greatly. But what kind of contributions has the policy made to regional economy in China? To what extent has the policy contributed to the regional economic development in China? To answer these questions, a preliminary study has been carried out based on qualitative and quantitative methods. Firstly, in this paper, the effects of the policy on regional economic development in China are expounded comprehensively: (1) Among the opening up policy series the preferential policies have been one of the main attracting forces to foreign investments;(2) owing to the opening up to the outside world, the economic growth rates in all regions in China are much higher than ever before;(3) through opening up to the outside world, export oriented economy has been playing increasingly important roles in the economic development in China, and foreign trade has become one of the major driving forces to the country’s economic growth; (4) since the 1980s the economic patterns and distributions in China have been changing greatly, the problems of energy shortages, transportation and communication infrastructures have been solved through using foreign investments, loans and technology. Secondly, through introducing policy function into C D production model, the contributions of the opening up policy to the Gross Domestic Products (GDP) growth of coastal areas (including eight provinces, one autonomous region and three municipalities directly under the central government, i.e., Guangdong, Hainan, Fujian, Zhejiang, Jiangsu, Shandong, Hebei, Liaoning, Guangxi, Beijing, Tianjin and Shanghai) in China have been calculated. Over the past two decades, from the early 1980s to the end of the 1990s, the GDP of the coastal areas has increased from about 18 billion RMB yuan to 115 billion RMB yuan. During the period the total increment of the GDP amounted up to 97 billion RMB yuan, in which about 21 billion RMB yuan is contributed by the policy. The average contribution rate of the policy to the GDP of the coastal areas of China is about 21.39%.
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    The Functional Structure of the Lower Changjiang River Port System
    CAO You hui, MAO Han ying, XU Gang
    2001, 56 (5):  590-598.  doi: 10.11821/xb200105010
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    Based on cargo commodity data of 12 principal ports of the lower Changjiang River, this paper calculates cargo location quotient of the port system in 1996.It can initially be seen that the port system has appeared the functional division system, which is characterized by three types and four sub types. However, there is not obvious functional disparity between several large ports (i.e. B1 type ports) and medium size, small ports. Sometimes, several medium sized and small ports possess too many specialized commodities. A practical formula of the coefficient of labour division of port(CLDP) is designed for determining the direction and degree of dynamic change of the functional structure of the port system. By calculating the concerned statistics from 1965 to 1996,it can be seen that CLDP in 1965 is 3.91, which was very high, then there appeared a steady tendency to drop. In 1996, CLDP reached its minimum which is 2.18. The above calculating results show that there has been to some extent homogeneity of the functional structure of this port system for recent 31 years. The authors hold that the following factors have profound implication on dynamic change of the functional structure of the port system: universal economic development along the lower Changjiang River, functional change of center port, homogeneity of industrial structure of port cities, transformation of management system of port. Comprehensive strength indexes of ports in the lower Changjiang River are calculated with the aid of R type factor analysis in which 12 evaluating indicators are as the cases. It can clearly be seen that there are four hierarchies of the functional structure of the port system. According to the above analysis results, the authors hold that there are three points for optimization of the functional structure of the port system:(1)Shanghai shall become a shipping center which is characterized by general cargo container transport and ship service;(2)Nanjing shall become a sub center port which is characterized by energy resource, other bulk cargo transit center;(3)Others shall be regional and local ports which provide service for economic development at local and regional levels.
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    The Ecological Footprints of the 12 Provinces of West China in 1999
    ZHANG Zhi qiang, XU Zhong min, CHENG Guo dong, CHEN Dong jing
    2001, 56 (5):  599-610.  doi: 10.11821/xb200105011
    Abstract ( )   PDF (425KB) ( )   Save
    The quantitative measurement of sustainable development has become one of the frontiers of sustainable development research since the sustainable development concept was put forward The ecological footprint indicator, put forward and developed by W E Rees and M Wackernagel since the early 1990s, is to measure the human impact on the earth and judge whether the human load stays within global carrying capacity The ecological footprint of any defined population (from a single individual to that of a whole city or country) is the total area of ecologically productive land and sea occupied to produce all the resources and services consumed and to assimilate all the wastes generated by that population With an area of about 6 88?10 6 km 2 which accounts for 71 67% of the total land area of China and 3 57?10 8 people accounting for 28 3% of the total population of China, the 12 provinces of West China have relatively low population density, and are abundant in natural resources but backward in economic development It is important to study the usage status of natural resources and sustainability of the 12 provinces of West China Based on the introduction to the concept and calculation method of ecological footprint indicator, the authors calculate and analyze the ecological footprints of the 12 provinces of West China in 1999 according to the data of the statistical yearbooks of these provinces According to this calculation, Yunnan Province and the Tibet Autonomous Region were the two provinces with ecological surplus, the other 10 provinces were all with ecological deficit The ecological surplus of Yunnan and Tibet were 0 145 hm 2 and 5 431 hm 2 per capita, respectively The Xinjiang Uygur Autonomous Region and Guizhou Province were the two provinces that have the largest ecological deficit, 1 261 hm 2 and 0 876 hm 2 per capita, respectively The ecological footprint and ecological deficit per capita of the 12 provinces of West China in 1999 were 1 172 hm 2 and 0 469 hm 2, respectively The total ecological footprint deficit of the 12 provinces of West China in 1999 is 1 625?10 6 km 2,which is equivalent to the area of the Xinjiang Uygur Autonomous Region The ecological footprint deficit shows that the human load has already stayed beyond the regional bio capacity, and the regional natural ecosystem is under great pressure of human activities We also point out the sustainability of the 12 provinces of West China according to the results of ecological footprints, and analyze the use efficiency of natural resources by calculating the ecological footprint needs of gross domestic product (GDP).
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    Dynamic Assessment for Soil Erosion Based on Land use-Structure Change
    NI Jin ren, LI Ying kui
    2001, 56 (5):  611-621.  doi: 10.11821/xb200105012
    Abstract ( )   PDF (465KB) ( )   Save
    The variation of land use structures is of significance to soil loss as well as ecological protection. Therefore, dynamic assessment of soil erosion and identification of the effect of human activities could be carried out by monitoring the land use change. Based on the analysis of characteristics of land use change and soil loss, this paper presents an approach for soil loss assessment in terms of land use structure change. The analytic hierarchy process is introduced to identify the impacts of land use on soil loss in terms of the hierarchical structure of regional landuse associated with different scales or resolutions, and weights at different levels could be determined with the pairwise comparison matrix. As a result, a characteristic index for land use structure is proposed to reflect the comprehensive impacts of various types of land use, which is defined as the sum of products between the weight assigned to each type of land use and its corresponding area percentage over the total for the concerned region. Moreover, a new dynamic assessment method for regional soil erosion is proposed based on the analogy of the rapid biological assessment method advanced for water quality in recent years. With a series of processes of selection of reference sites, classification of reference groups, determination of environmental indexes, identification of the matching groups for the concerned sites, and the comparison of the observed and expected results through an O/E ratio, the trend of the soil loss in an assessment area could be predicted very rapidly. A case study of the Zhifanggou Watershed in Ansai, Shaanxi Province was preformed and the systematic comparison of landuse characteristics from 1938 to 1999 was revealed. The characteristics from the assessment method are conformed to the major historical development processes in the study area and thus show flexibility for evaluation of regional soil erosion and ecological status. At the same time, the method retains most advantages in rapid ecological assessment method and pays more attention to dynamic variations rather than absolute status for regional soil erosion. It could also mitigate the limitations to regions and scales as encountered in other traditional methods, and is helpful to enhancing the assessment process for regional soil erosion and ecological quality in a dynamic manner. For large scale assessment, the presented method could be more flexible in data re use, and could save much time and expenses.
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    Life Path and Discipline Tree of Professor Chen Chuankang
    WU Bi hu
    2001, 56 (5):  622-630.  doi: 10.11821/xb200105013
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    It has been approved that life path and discipline tree techniques developed by time geographers are an effective method to examine academic thoughts and related activity characteristics for scientists, especially for those geographers who have rich time space path and traveling experiences in their lives. The author of this paper considered the technique suitable to observe personal experiences of Professor CHEN Chuan kang (1931~1997), the former vice president of the Geographical Society of China and a faculty of Department of Urban and Environmental Sciences, Peking University who had rich travel records, wide territories of research interests, and plenty of academic writings in his life span of 66 years. On the statistical basis of all his 1212 papers and books, the author firstly analyzed distributions of all works from the temporary dimension, which not only reflected changes of the number of Chen’s works with fluctuant evolutions of modern Chinese society, but also reflected the changes of the academic disciplines themselves. This kind of disciplinary shifts demonstrated both transformation of personal research interests of Professor Chen and transformation of the whole geographical development in China for about fifty years from the 1950s to 1990s. Secondly, using the concept of "discipline tree", the author checked Chen’s personal academic system, from both perspectives of disciplinary territories Chen had touched and evolutional process of these disciplines during Chen’s time, which could figure out an entire landscape of the professional experience of Chen’s creations to scientific knowledge.
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