Journal of Geographical Sciences 2002 Vol.12
Please wait a minute...
For Selected: Toggle Thumbnails
Pauperizing the pastoral periphery: the marginalization of herding communities in the world's dry lands
LI Ying, Douglas L. Johnson, Abdelkrim Marzouk
Journal of Geographical Sciences    2002, 12 (1): 1-14.  
Abstract797)      PDF(pc) (300KB)(52)       Save

Environmental degradation and other socio-economic problems are too often discerned in contemporary pastoral systems in the wake of global economic change. This paper identifies cases where pastoral people respond to external pressures and opportunities in positive ways and adapt to changes. We hope that by doing this a framework of pastoral adaptations can be developed. The first part of this paper focuses on impacts of global economic change, which are mostly negative in nature. Through an extensive literature search in geography, anthropology, range management, and development field, the second part introduces cases that we categorize as positive adaptations.

Related Articles | Metrics | Comments0
Cited: Baidu(1)
The global rainforest mapping project JERS-1:a paradigm of international collaboration for monitoring land cover change
DENG Xiang-zheng, ZHAN Jin-yan, LIU Ji-yuan, ZHUANG Da-fang
Journal of Geographical Sciences    2002, 12 (1): 15-22.  
Abstract954)      PDF(pc) (656KB)(55)       Save

The Global Rainforest Mapping (GRFM) project was initiated in 1995 and, through a dedicated data acquisition policy by the National Space Development Agency of Japan (NASDA), data acquisitions could be completed within a 1.5-year period, resulting in a spatially and temporally homogeneous coverage to contain the entire Amazon Basin from the Atlantic to the Pacific; Central America up to the Yucatan Peninsular in Mexico; equatorial Africa from Madagascar and Kenya in the east to Sierra Leone in the west; and Southeast Asia, including Papua New Guinea. To some extent, GRFM project is an international endeavor led by NASDA, with the goal of producing spatially and temporally contiguous Synthetic Aperture Radar (SAR) data sets over the tropical belt on the Earth by use of the JERS-1 L-band SAR, through the generation of semi-continental, 100m resolution, image mosaics. The GRFM project relies on extensive collaboration with the National Aeronautics and Space Administration (NASA), the Joint Research Center of the European Commission (JRC) and the Japanese Ministry of International Trade and Industry (MITI) for data acquisition, processing, validation and product generation. A science program is underway in parallel with product generation. This involves the agencies mentioned above, as well as a large number of international organizations, universities and individuals to perform field activities and data analysis at different levels.

Related Articles | Metrics | Comments0
Cited: Baidu(11)
Landscape distribution characteristics of northern foothill belts of Tianshan Mountains
CHENG Wei-ming, ZHOU Cheng-hu, TANG Qi-cheng, YAO Yong-hui,ZHANG Bai-ping
Journal of Geographical Sciences    2002, 12 (1): 23-28.  
Abstract992)      PDF(pc) (1864KB)(43)       Save

The foothill belts of Tianshan Mountains are about 280 km long and 60 km wide, and the study area extends from Kuitun city to Fukang city. They are transitional belts between mountains and plains, appearing in three rows of folds with different morphologies and their age becoming younger from south to north. Based on GIS and RS methods, and materials of the previous researchers, this paper deals with the genetics of the foothill belts and their landscape features resulting from folding by neotectonic movements, and also describes their length, width and slope by remote sensing image interpretation. The characteristics of the foothill belts are found to be very important for the surrounding environment by preventing groundwater from flowing into plains, changing groundwater, increasing flow of surface runoff, in addition to their roles in protecting the surrounding environment. The purpose of this paper is to provide an in-depth understanding of the foothill belts and influence on its surrounding environment.

Related Articles | Metrics | Comments0
Cited: Baidu(9)
Dynamic change of net primary productivity and fractional vegetation cover in the Yellow River Basin using multi-temporal AVHRR NDVI Data
SUN Rui, LIU Chang-ming, ZHU Qi-jiang
Journal of Geographical Sciences    2002, 12 (1): 29-34.  
Abstract781)      PDF(pc) (562KB)(44)       Save

An exponential relationship between net primary productivity (NPP) and integrated NDVI has been found in this paper. Based on the relationship and using multi-temporal 8 km resolution NOAA AVHRR-NDVI data, the spatial distribution and dynamic change of NPP and fractional vegetation cover in the Yellow River Basin from 1982 to 1999 are analyzed. Finally, the effect of rainfall on NDVI is examined. Results show that mean NPP and fractional vegetation cover have an inclining trend for the whole basin, and rainfall in flood season influences vegetation cover most.

Related Articles | Metrics | Comments0
Cited: Baidu(21)
Wetland vegetation biomass estimation and mapping from Landsat ETM data:a case study of Poyang Lake
LI Ren-dong, LIU Ji-yuan
Journal of Geographical Sciences    2002, 12 (1): 35-41.  
Abstract929)      PDF(pc) (833KB)(51)       Save

Poyang Lake is the largest freshwater lake in China. This paper conducted a digital and rapid investigation of the lake’s wetland vegetation biomass using Landsat ETM data acquired on April 16, 2000. First, utilizing the false color composite derived from the ETM data as one of the main references, the authors designed a reasonable sampling route for field measurement of the biomass, and carried it out on April 18-28, 2000. Then after both the sampling data and the ETM data were geometrically corrected to an equal-area projection of Albers, linear relationships among the sampling data and some transformed data derived from the ETM data and the ETM 4 were calculated. The results show that the sampling data is best relative to the band 4 data with a high correlation coefficient of 0.86, followed by the DVI and NDVI data with 0.83 and 0.80 respectively. Therefore, a linear regression model, which was based on the field data and band 4 data, was used to estimate the total biomass of entire Poyang Lake, and then the map of the biomass distribution was compiled.

Related Articles | Metrics | Comments0
Cited: Baidu(24)
Relationship between land cover and monsoon interannual variations in east Asia
XIANG Bao, LIU Ji-yuan
Journal of Geographical Sciences    2002, 12 (1): 42-48.  
Abstract759)      PDF(pc) (500KB)(48)       Save

Asian monsoon have multiple forms of variations such as seasonal variation, intra-seasonal variation, interannual variation, etc. The interannual variations have not only yearly variations but also variations among several years. In general, the yearly variations are described with winter temperature and summer precipitation, and the variations among several years are reflected by circulation of ENSO events. In this study, at first, we analyze the relationship between land cover and interannual monsoon variations represented by precipitation changes using Singular Value Decomposition method based on the time series precipitation data and 8km NOAA AVHRR NDVI data covering 1982 to 1993 in east Asia. Furthermore, after confirmation and reclassification of ENSO events which are recognized as the strong signal of several year monsoon variation, using the same time series NDVI data during 1982 to 1993 in east Asia, we make a Principle Component Analysis and analyzed the correlation of the 7th component eigenvectors and Southern Oscillation Index (SOI) that indicates the characteristic of ENSO events, and summed up the temporal-spatial distribution features of east Asian land cover’s inter-annual variations that are being driven by changes of ENSO events.

Related Articles | Metrics | Comments0
Cited: Baidu(12)
Erosion environment in the sediment-rich area on the Loess Plateau
JIAO Ju-ying, LI Jing, WANG Wan-zhong
Journal of Geographical Sciences    2002, 12 (1): 49-57.  
Abstract667)      PDF(pc) (374KB)(41)       Save

Based on the investigation and analysis of characteristics of precipitation, natural environment, socio-economic factors and soil erosion, this paper indicates that the precipitation is the main driving force for the soil erosion in the sediment-rich area, its variability determines the characteristics of soil and water loss; the natural conditions such as the drainage systems, geological and topographic features, the composition of soil and land surface materials, vegetation and climate determine the seriousness of soil and water loss; irrational socio-economic activities of human beings usually accelerated soil and water loss; meanwhile, the low preservation rate and inferiority of soil and water conservation measures made it impossible to make rapid progress on soil and water loss control. Furthermore, the characteristics of erosion environment endowed this area with more sediment that is the main reason for the flooding disasters by the Yellow River. Therefore, more emphasis should be placed on the enhancement of soil and water conservation. The soil loss prediction models will provide scientific basis for the planning of soil and water conservation, the designing of soil and water conservation measures and the valuation of effects of soil and water loss control. According to the analysis of the previous studies on soil loss prediction, and the water-sediment variation features, it is thought that study on soil loss prediction under various rainfall conditions and soil-water conservation measures should be carried out.

Related Articles | Metrics | Comments0
Cited: Baidu(15)
Total N, total P and organic matters content in floodplain soils of Xianghai Nature Reserve
DENG Wei, ZHAI Jin-liang, HE Yan
Journal of Geographical Sciences    2002, 12 (1): 58-64.  
Abstract797)      PDF(pc) (676KB)(51)       Save

Soil sediment samples of 10 layers with a spacing of 10 cm each were collected in different floodplain zones adjacent to Huolin River in the Xianghai Nature Reserve, and contents of total N, total P and organic matters were analyzed. The results showed that contents of total N, total P and organic matters were generally decreasing with the increase of distance from sample locations to the river channel, and contents of the three items were generally higher in the upper soil layer than that in the lower soil layer. The content variations displayed how flooding functions influenced nutrient matter content variations in floodplain soils since the flood inundation frequencies of the sample locations varied. The correlation analysis displayed that there were remarkable relativities between total N, total P and organic matters within definite spatial distance from the Huolin River channel.

Related Articles | Metrics | Comments0
Cited: Baidu(7)
Sedimentary cycles of trace elements in Salawusu River Valley since 150 ka BP
YAO Chun-xia, LI Bao-sheng, JIN He-ling, David Dian Zhang, YAN Man-cun, ZHU Yi-zhi, LI Hou-xin, ZHANGYu-hong,Luo Kai-li
Journal of Geographical Sciences    2002, 12 (1): 65-71.  
Abstract938)      PDF(pc) (1104KB)(35)       Save

The paper makes some analyses on 11 trace elements in the Milanggouwan stratigraphical section in the Salawusu River valley, which is regarded as a prototype geology-palaeoclimate record since 150 ka BP. The results show that the content and variation of trace elements has experienced remarkably regular changes in the pace with coarse and fine sedimentary cycles of palaeo-aeolian sands to its overlying fluvio-lacustrine facies or/and palaeosols. The trace elements with chemical properties of relatively active (V, Sr, Cu, Ni, As) and relatively stable (P, Pb, Rb, Mn, Nb, Zr) are a manifestation of the corresponding 27 changeable cycles between peak and valley values, appearing a multi-fluctuational process line of relative gathering and migration since then. The low numerical value distribution of these two types of trace elements in the aeolian sand facies represents erosion and accumulation under wind force during the cold-dry climate. Whereas their enrichments in both fluvio-lacustrine facies and palaeosols are related to the valley’s special low-lying physiognomic position between the Ordos Plateau and the Loess Plateau under the warm and humid climate conditions. The above relatively migrated and gathered change of the trace elements is the result of 27 climatic cycles of cold-dry and warm-humid, which is probably caused by repeated alternations of winter monsoon and summer monsoon in the Mu Us Sandy Land influenced by the climate vicissitudes in northern hemisphere during glacial and interglacial periods since 150 ka BP.

Related Articles | Metrics | Comments0
Cited: Baidu(64)
Straight river: its formation and speciality
WANG Sui-ji, NI Jin-ren
Journal of Geographical Sciences    2002, 12 (1): 72-80.  
Abstract1322)      PDF(pc) (51KB)(60)       Save

Straight river is generally regarded as one of the typical river patterns in conventional classifications in terms of their channel plain landforms. However, very few straight patterns were found to be distributed in wider spatial and temporal spans in the self-adjusted fluvial rivers. Thus, the questions occur such as that is it possible for a channel takes on a stable straight pattern? What are the main factors controlling the processes of the river pattern formation and transformation from a straight to other patterns? Various theories and hypotheses including geomorphic threshold hypothesis, the extreme hypothesis on energy dissipation rate, the stability theory, etc. have been developed to explain the aforementioned questions, but none of them is sound for the explanation to the straight-river formation. From the modern fluvial plain patterns, the straight patterns are not as stable as other typical patterns which occurred in nature; from the historic records of the river sedimentation, no apparent evidence was found to support the stable straight river evolution. Based on the analysis of existing theories, observations, evolvement processes of the channel patterns in the experimental results, this paper concluded that the straight pattern should not be included as one of the typical patterns that are self-formed and developed. This study is of importance to understanding of the river pattern formation and transformation.

Related Articles | Metrics | Comments0
Cited: Baidu(2)
Developmetn stage threshold of watershed Landforms in Loess Plateau and separation of erosion mechanism
LU Zhong-chen, CHEN Shao-feng,YUAN Bao-yin,CHEN Hao
Journal of Geographical Sciences    2002, 12 (1): 81-90.  
Abstract938)      PDF(pc) (1997KB)(49)       Save

Threshold is a limit and marginal point when a qualitative change takes place.Since threshold principle was firstly used in landform research by S.A.Schumm in the 1970s,the quantitative research on watershed landform development stage has come true.Davis proposed a three-stage model on landform evolution:young ,mature and old stages.Thereafter Stahler quantified this model by hypsometric analysis method.The authors thought that the material movement stage cannot be expressed by hypsometric method in watershed landform at development stage,because of the uncertainty on stage delimitaion.To meet this shortcoming,this paper presents an integral erosion value method.A clear delimitation on landform development stage in the Loess Plateau region has been tested by this method.The result shows that gullied loessial hilly area is at the mature stage,and gullied loessial tableland area is at the young stage.It is estimated that from the point of erosion related sediment yield,natural erosion accounts for 70% of the total erosion amount,and artificial accelerating erosion is 30%.Therefore soil and water conservation is very crucial for the Loess Plateau.

Related Articles | Metrics | Comments0
Cited: Baidu(2)
The cooling fluctuation events during Holocene in the tropical zone of China
HUANG Zhen-guo, ZHANG Wei-qiang
Journal of Geographical Sciences    2002, 12 (1): 91-98.  
Abstract759)      PDF(pc) (2901KB)(58)       Save

Forty-eight samples are chosen to discuss the distribution in space and time of the cooling fluctuation events during HoloCene in the tropical zone of China in this paper. The authors consider that the Neoglaciations II and III (or Cooling Event ①) have a widespread impact on the drop in temperature of 1-2 oC or less than 2 oC. The YD Event was dated at 11,300-10,200 a BP in the tropical mainland and its dating is 11,400-10,500 a BP in the sea area with a drop in temperature of 4-6 oC. The distribution of Event B and Neoglaciation I is taking a position of north, with a drop in temperature of 2.5-3.0 oC. The Cooling Event ② shows the temporality in time. The Cooling Event ③ shows the limitation of regional distribution with a drop in temperature of less than 1.5oC. The more recent the cooling event is, the smaller the drop amplitude in temperature will be. In the eastern part of tropical zone seven events are complete in all varieties but the cooling fluctuation is weaker in the western part. In Hainan Island and South China Sea the appearance of cooling fluctuations is synchronous with each other.

Related Articles | Metrics | Comments0
Cited: Baidu(15)
Anomaly feature of seasonal frozen soil variations on the Qinghai-Tibet Plateau
WANG Cheng-hai, DONG Wen-jie, WEI Zhi-gang
Journal of Geographical Sciences    2002, 12 (1): 99-107.  
Abstract923)      PDF(pc) (344KB)(54)       Save

The seasonal frozen soil on the Qinghai-Tibet Plateau has strong response to climate change, and its freezing-thawing process also affects East Asia climate. In this paper, the freezing soil maximum depth of 46 stations covering 1961-1999 on the plateau is analyzed by rotated experience orthogonal function (REOF). The results show that there are four main frozen anomaly regions on the plateau, i.e., the northeastern, southeastern and southern parts of the plateau and Qaidam Basin. The freezing soil depths of the annual anomaly regions in the above representative stations show that there are different changing trends. The main trend, except for the Qaidam Basin, has been decreasing since the 1980s, a sign of the climate warming. Compared with the 1980s, on the average, the maximum soil depth decreased by about 0.02 m, 0.05 m and 0.14 m in the northeastern, southeastern and southern parts of the plateau, but increased by about 0.57 m in the Qaidam Basin during the 1990s. It means there are different responses to climate system in the above areas. The spectrum analysis reveals different change cycles: in higher frequency there is an about 2-year long cycle in Qaidam Basin and southern part of the plateau in the four representative areas whereas in lower frequency there is an about 14-year long cycle in all the four representative areas due to the combined influence of different soil textures and solutes in four areas.

Related Articles | Metrics | Comments0
Cited: Baidu(27)
Arable land increase in northern China:facts and findings
SONG Jin-ping, LI Xiu-zhen
Journal of Geographical Sciences    2002, 12 (1): 108-113.  
Abstract1029)      PDF(pc) (35KB)(48)       Save

Based on investigations between 1986 and 1996 in the four provinces of northern China, major problems on land reclamation were discovered. The increase of arable land was mainly low quality fields from barren land and was susceptible to disertification and water-induced soil erosion. In the meantime, large area of grassland and forestland was lost or degraded, and original fertile arable land was occupied for residential and industrial use. As a result the environment deteriorated. This change was mainly caused by economic development, population growth, inferior natural conditions, and irrational management strategies. Finally some positive measures were suggested to stop this negative cycle.

Related Articles | Metrics | Comments0
Cited: Baidu(4)
Research progress of socio-economic water cycle in China
JIA Shao-feng, WANG Guo, ZHANG Shi-feng, YU Gui-rui,WANG Jin-xia, XIA Jun
Journal of Geographical Sciences    2002, 12 (1): 114-120.  
Abstract973)      PDF(pc) (46KB)(62)       Save

China has made great progress in the study of socio-economic water cycle. She has completed national water resources appraisement and medium to long-term water supply planning. She has been engaging in study on water-deficient regions in North China and Northwest China for about half a century. For solving water shortage problem in northern China, she has put forward the famous South-to-North Water Transferring Projects, which has been set as one of the four biggest national projects in the Tenth Five-Year-Plan period although there are still debates. For promoting water use efficiency, China has been reforming her water management system, including water right system and water price system. There has already been a case of water right purchase. China has also done a lot of research on the interaction between human activity, water and ecosystem. For meeting the need of sustainability and coordinating water resources development and environmental protection, the study of ecological water requirement became very hot in recent years. There are three focuses of socio-economic water cycle study now in China: water transfer projects from the south to the north, water resources management and ecological water requirement.

Related Articles | Metrics | Comments0
Cited: Baidu(50)
Integrated ecosystem assessment for western development of China
LIU Ji-yuan, Masataka Watanabe, YUE Tian-xiang, OUYANG Hua, DENG Xiang-zheng
Journal of Geographical Sciences    2002, 12 (2): 127-134.  
Abstract879)      PDF(pc) (1364KB)(45)       Save

The objectives of Integrated Ecosystem Assessment for Western Development of China includes: (1) providing scientific basis for ecosystem protection, ecosystem management and ecological construction in the western development; (2) developing complete database and analytical tools and strengthening decision-making support capacity; and (3) improving ecosystem management in China, spreading ecological knowledge to the public, serving decision-making of local and central governments, and promoting socio-economic sustainable development. The design and implementation of the project are of significance under the macro background of western development of China. By the integrated assessment of western China, we can get the first-hand data covering all the environmental factors as well as disclose the situations and their changing trends of ecosystem in the western part of China, which will benefit the decision-making for the central and local governments in the implementation of the western development strategy. In other words, the implementation of the project, to a certain extent, can guarantee the regional sustainable development of western China.

Related Articles | Metrics | Comments0
Cited: Baidu(31)
Biodiversity and conservation in the Tibetan Plateau
ZHANG Bai-ping, CHEN Xiao-dong, LI Bao-lin, YAO Yong-hui
Journal of Geographical Sciences    2002, 12 (2): 135-143.  
Abstract970)      PDF(pc) (1998KB)(63)       Save

The Tibetan Plateau (Qinghai-Xizang Plateau) is a unique biogeographic region in the world, where various landscapes, altitudinal belts, alpine ecosystems, and endangered and endemic species have been developed. A total of 26 altitudinal belts, 28 spectra of altitudinal belts, 12,000 species of vascular plant, 5,000 species of epiphytes, 210 species of mammals, and 532 species of birds have been recorded. The plateau is also one of the centers of species formation and differentiation in the world. To protect the biodiversity of the plateau, about 80 nature reserves have been designated, of which 45 are national or provincial, covering about 22% of the plateau area. Most of the nature reserves are distributed in the southeastern plateau. Recently, the Chinese government has initiated the “Natural Forests Protection Project of China,” mainly in the upper reaches of the Yangtze and Yellow rivers. “No logging” policies have been made and implemented for these areas.

Related Articles | Metrics | Comments0
Cited: Baidu(36)
The property, age and formation environment of the palaeokarst in Qinghai-Xizang Plateau
GAO Quan-zhou, CUI Zhi-jiu, TAO Zhe1, LIU Geng-nian,HONG Yun
Journal of Geographical Sciences    2002, 12 (2): 144-152.  
Abstract1344)      PDF(pc) (920KB)(54)       Save

The karst landforms distributed on the Qinghai-Xizang (Tibet) Plateau can be genetically classed with the Tertiary underground karst, which were gradually exhumed to the surface with the uplift of the plateau during Quaternary period. The relative deposits of the Tertiary palaeokarst processes, such as the residuum and speleothem, were discovered recently in the southern and southeastern fringe areas of the plateau, where has geological-currently been disintegrated by the headward erosion processes of the modern river systems. The major chemical components of the clay portion of the residuum consist mainly of SiO2C, Al2CO3 and Fe2O3. The clay minerals composition of the clay portion belongs to illite-kaolinite pattern for most of the residuum samples, and kaolinite-illite pattern for a few of the samples. It can be judged from the silicic acid index and the clay minerals composition that the formation of the residuum of the Plateau was in its initial phase. However, such a lower chemical weathering index only reflected the weathering degree in the bottom or lower parts of the lateritic weathering crust. The relatively intensive chemical weathering processes of the surface layers of the lateritic weathering crust could be logically speculated. The surface feature textures of quartz grains in the residuum were formed mainly by the chemical erosion, which revealed a long-term humid-tropical environment when the residuum and the palaeokarst formed.

Related Articles | Metrics | Comments0
Cited: Baidu(7)
Spatial changes of wind erosion-caused landscapes and their relation with wind field in China
ZHANG Guo-ping, LIU Ji-yuan, ZHANG Zeng-xiang,ZHAO Xiao-li, ZHOU Quan-bin
Journal of Geographical Sciences    2002, 12 (2): 153-162.  
Abstract701)      PDF(pc) (2151KB)(22)       Save

Based on the results of remote sensing investigations of the landscapes of 1995 and 2000, the national distribution of sandy desertified land and its interaction with other landscapes are classified, and five zonal types are distinguished. The data of nationally distributed 400 meteorological stations of 1999 are processed. With the GIS method, the data are spatially interpolated, and the national database of wind field concerned with wind erosion is established. In arid and semi-arid areas of China, the intensity of wind field is one of the key factors that controls the development of landscape especially in desert and its adjacent area. Different indexes are set up to describe the intensity of wind field, the method suggested by the wind erosion prediction models of RWEQ is also adopted to express the intensity of wind. The Weibull distribution is used to describe the wind field in China. Based on the analysis of the process of the wind erosion-driven landscape changes, this article proposes and discusses the control measures of wind erosion.

Related Articles | Metrics | Comments0
Cited: Baidu(3)
Internet based environmental monitoring information system and its application in Yili Prefecture
DENG Xiang-zheng, LIU Ji-yuan, ZHUANG Da-fang, ZHAN Jin-yan
Journal of Geographical Sciences    2002, 12 (2): 163-170.  
Abstract701)      PDF(pc) (2363KB)(28)       Save

With the development of Internet technologies, Internet Based Information System (IBIS) arises with more advantages: Firstly, it is convenient for users to use owing to the introduction of Internet technologies. Secondly, it benefits greatly the data dissemination and data sharing based on Internet. The most important but not the last is that we can establish the information service network supported by its technologies and the facilities of information highway. So, it would be significant to design IBIS to realize the data collection, sharing and dissemination on Internet. There are many factors affecting regional environment. So it is not easy to realize the integrated environmental monitoring. Given this, we designed the Internet based environmental monitoring information system. By the virtue of the Internet based environmental monitoring information system, the management and storage of environmental monitoring data would be easier, which lays the foundation to actualize the environmental monitoring efficiently.

Related Articles | Metrics | Comments0
Cited: Baidu(32)
A GIS-based research on the distribution of rural settlements in Yulin of northern Shaanxi
ZHAO Mu-dan, TANG Guo-an, SHI Wen-zhong, LIU Yong-mei
Journal of Geographical Sciences    2002, 12 (2): 171-176.  
Abstract795)      PDF(pc) (886KB)(38)       Save

The development and distribution pattern of rural settlements was greatly limited by their natural and social environment. Taking Yulin prefecture in northern Shaanxi’s Loess Plateau area as an example, 1:250,000 map-scale national geographical database as a major information source, a GIS-based research was conducted to investigate the spatial distribution of the rural settlements. In this paper, many significant characteristics of the rural settlement distribution are reviewed by means of a series of GIS-based information processing methodology. The results obtained in this study should be helpful for the urban and rural settlements reconstruction planning in this area.

Related Articles | Metrics | Comments0
Cited: Baidu(12)
Regional carrying capacity: case studies of Bohai Rim area
YU Dan-lin, MAO Han-ying
Journal of Geographical Sciences    2002, 12 (2): 177-185.  
Abstract1161)      PDF(pc) (64KB)(62)       Save

Carrying capacity research has been carried out for a long time. However, synthesized carrying capacity researches based on systematic views began only in the 1970s. There is even less work done in China. This paper tries to address both synthesized carrying capacity research and its utilization in China. State spaces method from the systematic science was borrowed to construct the conceptual model of regional carrying capacity. Based on the conceptual model and the surveys in the Bohai Rim area, we construct a representative indicators system for quantifying regional carrying capacity in the Bohai Rim. While employing system dynamic models we simulated the evolving trend of both the regional carrying states and regional carrying capacity from 1999 to 2015. The results proved the statement that Bohai Rim is overall over-capacity for a long time and will be over-capacity in the foreseeable future. Among all the restriction factors, water shortage and environmental pollution stand out to be the two primary obstacles for Bohai Rim’s sustainable development. Regional differentiation analysis further indicates that coastal areas of the Bohai Rim burden more than its overall level. However, Shandong province shows some good signs in addressing the regional carrying capacity issues. The research is successful in addressing the quantification of regional carrying capacity issues, but nonetheless it needs further refinery and more information.

Related Articles | Metrics | Comments0
Cited: Baidu(32)
On models for landscape connectivity:a case study of the new-born wetland of the Yellow River Delta
YUE Tian-xiang, YE Qing-hua, LIU Qing-sheng,GONG Zheng-hui
Journal of Geographical Sciences    2002, 12 (2): 186-195.  
Abstract1187)      PDF(pc) (1501KB)(47)       Save

The models for landscape connectivity are distinguished into models for line connectivity, vertex connectivity, network connectivity and patch connectivity separately. Because the models for line connectivity, for vertex connectivity, and for network connectivity have long been studied and have become ripe, the model for patch connectivity is paid special attention in this paper. The patch connectivity is defined as the average movement efficiency (minimizing movement distance) of animal migrants or plant propagules in patches of a region under consideration. According to this definition, a model for landscape connectivity is mathematically deduced to apply to GIS data. The application of model for patch connectivity in the new-born wetland of the Yellow River Delta shows patch connectivity has a negative interrelation with human impact intensity and landscape diversity.

Related Articles | Metrics | Comments0
Cited: Baidu(49)
The paleogeographic implications of loess mounds: Laizhou Bay plain
ZHANG Zu-lu, LIU En-feng, NIE Xiao-hong, WANG Lin
Journal of Geographical Sciences    2002, 12 (2): 196-201.  
Abstract899)      PDF(pc) (466KB)(56)       Save

The loess mounds are a newly discovered type of landforms on the Laizhou Bay plain south of the Bohai Sea. Research shows that they were formed in the late period of the late Pleistocene when the Bohai Sea was exposed in the period of late Wümu glacial age and changed into plain. As the exposed area is not protected by vegetation, the sediments at the sea bottom are blown and transported southward by strong north winds, and deposit on the coastal plains. As thick loess is accumulated, the loess mound landforms are formed in the direction of down wind.

Related Articles | Metrics | Comments0
Interdecadal change in Western Pacific Subtropical High and climatic effects
HE Xue-zhao, GONG Dao-yi
Journal of Geographical Sciences    2002, 12 (2): 202-209.  
Abstract1192)      PDF(pc) (440KB)(97)       Save

Western North Pacific Subtropical High is a very important atmospheric circulation system influencing the summer climate over eastern China. Its interdecadal change is analyzed in this study. There is a significant decadal shift in about 1979/1980. Since 1980, the Western North Pacific Subtropical High has enlarged, intensified, and shifted southwestward. This change gives rise to an anti-cyclonic circulation anomaly over the region from the South China Sea to western Pacific and thus causes wet anomalies over the Yangtze River valley. During the summers of 1980-1999, the precipitation is 63.9 mm above normal, while during 1958-1979 it is 27.3 mm below normal. The difference is significant at the 99% confidence level as a t-test shown. The southwestward expanding of the Western North Pacific Subtropical High also leads to a significant warming in southern China, during 1980-1999 the summer mean temperature is 0.37oC warmer than that of the period 1958-1979. The strong warming is primarily due to the clearer skies associated with the stronger downward air motion as the Western North Pacific Subtropical High expanding to the west and controlling southern China. It is also found that the relative percentage of tropical cyclones in the regions south of 20oN is decreasing since the 1980s, but in the regions north of 20oN that is increasing at the same time. The Western North Pacific Subtropical High responds significantly to sea surface temperature of the tropical eastern Pacific with a lag of one-two seasons and simultaneously to sea surface temperature of the tropical Indian Ocean. The changes in the sea surface temperatures are mainly responsible for the interdecadal variability of the Western North Pacific Subtropical High.

Related Articles | Metrics | Comments0
Cited: Baidu(194)
Interdecadal fluctuation of dry and wet climate boundaries in China in the past 50 years
YANG Jian-ping, DING Yong-jian, CHEN Ren-sheng,LIU LIAN-you
Journal of Geographical Sciences    2002, 12 (2): 210-216.  
Abstract818)      PDF(pc) (1076KB)(33)       Save

Based on the mean yearly precipitation and the total yearly evaporation data of 295 meteorological stations in China in 1951-1999, the aridity index is calculated in this paper. According to the aridity index, the climatic regions in China are classified into three types, namely, arid region, semi-arid region and humid region. Dry and wet climate boundaries in China fluctuate markedly and differentiate greatly in each region in the past 50 years. The fluctuation amplitudes are 20-400 km in Northeast China, 40-400 km in North China, 30-350 km in the eastern part of Northwest China and 40-370 km in Southwest China. Before the 1980s (including 1980), the climate tended to be dry in Northeast China and North China, to be wet in the eastern part of Northwest China and very wet in Southwest China. Since the 1990s there have been dry signs in Southwest China, the eastern part of Northwest China and North China. The climate becomes wetter in Northeast China. Semi-arid region is the transitional zone between humid and arid regions, the monsoon edge belt in China, and the susceptible region of environmental evolution. At the end of the 1960s dry and wet climate in China witnessed abrupt changes, changing wetness into dryness. Dry and wet climate boundaries show the fluctuation characteristics of the whole shifts and the opposite fluctuations of eastward, westward, southward and northward directions. The fluctuations of climatic boundaries and the dry and wet variations of climate have distinctive interdecadal features.

Related Articles | Metrics | Comments0
Cited: Baidu(52)
Groundwater regime and calculation of yield response in North China Plain: a case study of Luancheng County in Hebei Province
JIA Jin-sheng, YU Jing-jie, LIU Chang-ming
Journal of Geographical Sciences    2002, 12 (2): 217-225.  
Abstract975)      PDF(pc) (1962KB)(57)       Save

The groundwater table has been declining at a rate of 0.65 m/yr in Luancheng County since large scale groundwater extraction carried out in the 1960s. The drop of precipitation, substantial increase in agricultural output, variations of crop planting structure and construction of water conservancy projects in the headwater area all tie up with the decline of the groundwater table. On the basis of analyzing the hydrogeological conditions and the water resources utilization of Luancheng County, a three-dimensional groundwater flow model was developed to simulate the county’s groundwater flow through finite-difference method using Visual Modflow software. We divide the research field into four parts after analyzing the hydrogeological condition. Based on parameter calibration and adjustment using measured data, the hydraulic conductivity and specific yield were simulated. Using the calibrated model, we analyze the agricultural water saving potentiality and its influence on the groundwater. The results are as follows: (1) if we decrease the amount of water extracted by 0.14×108 m3, the average groundwater table of the five observation wells in December will rise by 0.33 m; (2) if we decrease the water by 0.29× 108 m3, the average groundwater table of the five observation wells in December will rise by 0.64 m; and (3) if we increase the water by 0.29×108 m3, the average groundwater table of the five observation wells in December will decline by 0.45 m. So we can draw a conclusion that controlling the agricultural water use is an important way to prevent the decline of groundwater table.

Related Articles | Metrics | Comments0
Cited: Baidu(48)
The 3D simulation and optimized management model of groundwater systems based on eco-environmental water demand
ZHANG Guang-xin, DENG Wei, HE Yan
Journal of Geographical Sciences    2002, 12 (2): 226-235.  
Abstract924)      PDF(pc) (1146KB)(46)       Save

Through the study of mutual process between groundwater systems and eco-environmental water demand, the eco-environmental water demand is brought into groundwater systems model as the important water consumption item and unification of groundwater’s economic, environmental and ecological functions were taken into account. Based on eco-environmental water demand at Da’an in Jilin province, a three-dimensional simulation and optimized management model of groundwater systems was established. All water balance components of groundwater systems in 1998 and 1999 were simulated with this model and the best optimal exploitation scheme of groundwater systems in 2000 was determined, so that groundwater resource was efficiently utilized and good economic, ecologic and social benefits were obtained.

Related Articles | Metrics | Comments0
Cited: Baidu(7)
Chemical element transfer of weathering granite regolith in the Three Gorges Dam region of Yangtze River
ZHANG Li-ping, ZHU Da-kui, YANG Da-yuan
Journal of Geographical Sciences    2002, 12 (2): 236-242.  
Abstract944)      PDF(pc) (59KB)(44)       Save

Clearing up sediment and regolith on the foundation of the dam in the Three Gorges of the Yangtze River in 1999, riverbed were exposed. On the basis of weathering granite regolith sampled from different portions of the valley landforms, by analysing total chemical contents with X rays fluorescent slice and calculating proper value of chemical element transferring ratio and intensity, the transferring law of chemical elements in different portions of the landforms were concluded: 1) In various landforms of the river valley, the process of desilication is not distinct; 2) in weathering granite regolith of riverbed, easy soluble CaO and MgO are relatively enriched whereas Al2O3 tends to decrease. The enriching rate of Fe2O3 is the greatest in various landforms of the river valley; 3) in weathering granite regolith of flood-plain, K2O and MgO contents are relatively enriched; 4) the weathering granite regolith of valley slope is a typical north subtropical weathering regolith, and its chemical weathering degree is in the transition phase from early to middle period; and 5) there is an opposite layer where K2O is relatively leaching and Na2O relatively enriching in 6.5 m depth of all weathering granite regolith.

Related Articles | Metrics | Comments0
Cited: Baidu(3)
Soil degradation: a global problem endangering sustainable development
CHEN Jie, CHEN Jing-zhang, TAN Man-zhi, GONG Zi-tong
Journal of Geographical Sciences    2002, 12 (2): 243-252.  
Abstract1266)      PDF(pc) (2575KB)(89)       Save

Soil degradation, defined as lowering and losing of soil functions, is becoming more and more serious worldwide in recent decades, and poses a threat to agricultural production and terrestrial ecosystem. It is estimated that nearly 2 billion ha of soil resources in the world have been degraded, namely approximately 22% of the total cropland, pasture, forest, and woodland. Globally, soil erosion, chemical deterioration and physical degradation are the important parts amongst various types of soil degradation. As a natural process, soil degradation can be enhanced or dampened by a variety of human activities such as inappropriate agricultural management, overgrazing, deforestation, etc. Degraded soil means less food. As a result of soil degradation, it is estimated that about 11.9-13.4% of the global agricultural supply has been lost in the past five decades. Besides, soil degradation is also associated with off-site problems of sedimentation, climate change, watershed functions, and changes in natural habitats leading to loss of genetic stock and biodiversity. Therefore, it is essential to combat soil degradation at different levels and scales worldwide, not only for food security and ecological health, but also for the guarantee of global sustainable development.

Related Articles | Metrics | Comments0
Cited: Baidu(124)
Land use and landscape pattern change: a linkage to the construction of the Qinghai-Xizang Highway
YAN Jianzhong, ZHANG Yili, LIU Linshan, LIU Yanhua, ZHENG Du
Journal of Geographical Sciences    2002, 12 (3): 253-265.  
Abstract920)      PDF(pc) (630KB)(46)       Save

Based on digital land use data from 1995 to 2000 and road data, the land use and landscape changes of Golmud, Qumaleb and Zhidoi are studied on a macro-scale. Land use and landscape changes in highway buffer zones and city expansion are special subjects. A new formula is used to define the exact degree of dynamic land use. To adequately define land use and landscape pattern changes, the buffer zones, illustrating the changes at different distances from the road, are recognized with ArcGIS 8.1 software. Prominent changes took place in land use and landscape patterns from 1995 to 2000, and the area of built-up land increased by 323.8%. The comprehensive degree of dynamic land use is 2.25, and the degree of dynamic land use of built-up land is the highest, followed by cultivated land. Woodland has the lowest value. The used degree index of land resources declined by 38.8 from 1995 to 2000. Landscape changed dramatically which influenced ecological processes immensely. Different from the corridor effect of other traffic routes, the corridor effect of this section of road is not obvious and its "point" radiation effect can be easily seen. The expanding range of Golmud City is confined to a 3 km buffer, while for Wudaoliang, it is 1 km. No land use change happened in the Nanshankou buffer.

Related Articles | Metrics | Comments0
Cited: Baidu(31)
Spatial patterns of urban land use growth in Beijing
LIU Shenghe, Sylvia Prieler, LI Xiubin
Journal of Geographical Sciences    2002, 12 (3): 266-274.  
Abstract998)      PDF(pc) (1351KB)(57)       Save

By using digitized land use maps of Beijing in 1982, 1992 and 1997 and employing GIS spatial analysis techniques, this paper conducts an empirical study on the spatial differentiation and spatial patterns of urban land use growth in Beijing in the period of 1982-1997. It is observed that urban land use growth in Beijing went beyond the control of urban planning, in terms of the extraordinary high growth rate and undesired spatial pattern. The rate of urban expansion after 1982, which was predominated by growth of industrial land, was extraordinary high compared to its historical period. While its growth centers have been actively shifting toward the northern part, rather than toward the southern and eastern parts as designated by the latest General Plan (1991-2010) of Beijing, its spatial pattern of urban land use growth in general was in distinct concentric sprawl, which seriously violated the General Plan of Beijing.

Related Articles | Metrics | Comments0
Cited: Baidu(64)
The land use and land cover change database and its relative studies in China
LIU Jiyuan, LIU Mingliang, DENG Xiangzheng, Zhuang Dafang,ZHANG Zengxiang, LUO Di
Journal of Geographical Sciences    2002, 12 (3): 275-282.  
Abstract2095)      PDF(pc) (445KB)(95)       Save

In the mid-1990s, we established the national operative dynamic information serving systems on natural resources and environment. During building the land-use/land-cover change (LUCC) database for the mid-1990s, 520 scenes of remotely sensed images of Landsat Thematic Mapper (TM) were interpreted into land-use/land-cover categories at scale of 1:100,000 under overall digital software environment after being geo-referenced and ortho-rectified. The vector map of land-use/land-cover in China at the scale of 1:100,000 was recently converted into a 1-km raster database that captures all of the high-resolution land-use information by calculating area percentage for each kind of land use category within every cell. Being designed as an operative dynamic information serving system, monitoring the change in land-use/land-cover at national level was executed. We have completed the updating of LUCC database by comparing the TM data in the mid-1990s with new data sources received during 1999-2000 and 1989-1990. The LUCC database has supported greatly the national LUCC research program in China and some relative studies are incompletely reviewed in this paper.

Related Articles | Metrics | Comments0
Cited: Baidu(269)
Natural eco-environmental evaluation of eastern Qinghai-Tibet Plateau using RS and GIS
YANG Shengtian, LIU Changming, YANG Zhifeng, SUN Rui, ZHOU Xiaodong
Journal of Geographical Sciences    2002, 12 (3): 283-288.  
Abstract1122)      PDF(pc) (414KB)(69)       Save

The impact of interbasin water transfer on environment is very significant. The affected area of the west route scheme of the South to North Water Transfer Project in China (SNWT) is located in the eastern Tibetan Plateau, where the altitude is high with frigid eco-environment. In this article, remote sensing and GIS are applied to analyze the natural environment and the natural environment index is established to express the natural conditions of the study area. After the natural environment index is divided into four grades and the features of each grade are analysed, some results are obtained for reference in environmental assessment of the west route of SNWT.

Related Articles | Metrics | Comments0
Cited: Baidu(4)
The responses of hydro-environment system in the Second Songhua River Basin to melt water
YAN Denghua, DENG Wei, HE Yan
Journal of Geographical Sciences    2002, 12 (3): 289-294.  
Abstract909)      PDF(pc) (249KB)(68)       Save

Based on the continuous monitoring data of hydrology and water quality in the period from 1972 to 1997, the responses of hydro-environment system to melt water in the Second Songhua River basin were derived. Because of melt water, the water quality in the Second Songhua River is good and changes very except that the contents of Hg and Mn in the water are higher. The contribution of melt water to the water fluxes in the Second Songhua River basin is distinct: the water flow in April increases remarkably, reaches the peak in the upper reaches. The pollutant contributions and water pollution indices (WPIs) of the Second Songhua River in April are high in the upper reaches while that in the lower reaches are low. The responses of hydro-environment system to melt water of that basin are affected by content of packed snow and the underlining surface systems.

Related Articles | Metrics | Comments0
Cited: Baidu(1)
Variation of fluxes of water vapor, sensible heat and carbon dioxide above winter wheat and maize canopies
ZHANG Yongqiang, SHEN Yanjun, YU Qiang, LIU Changming, A. Kondoh, TANG Changyuan, SUN Hongyong, JIA Jinsheng
Journal of Geographical Sciences    2002, 12 (3): 295-300.  
Abstract961)      PDF(pc) (361KB)(56)       Save

Surface energy fluxes were measured using Bowen-Ratio Energy Balance technique (BREB) and eddy correlation system at Luancheng of Hebei Province, on the North China Plain from 1999 to 2001. Average diurnal variation of surface energy fluxes and CO2 flux for maize showed the inverse "U" type. The average peak fluxes did not appear at noon, but after noon. The average peak CO2 flux was about 1.65 mg m-2 s-1. Crop water use efficiency (WUE) increased quickly in the morning, stabilized after 10:00 and decreased quickly after 15:00 with no evident peak value. The ratio of latent heat flux (λE) to net solar radiation (Rn) was always higher than 70% during winter wheat and maize seasons. The seasonal average ratio of sensible heat flux (H) divided by Rn stayed at about 15% above the field surface; the seasonal average ratio of conductive heat flux (G) divided by Rn varied between 5% and 13%, and the average G/Rn from the wheat canopy was evidently higher than that from the maize canopy. The evaporative fraction (EF) is correlated to the Bowen ratio in a reverse function. EF for winter wheat increased quickly during that revival stage, after the stage, it gradually stabilized to 1.0, and fluctuated around 1.0. EF for maize also fluctuated around 1.0 before the later grain filling stage, and decreased after that stage.

Related Articles | Metrics | Comments0
Cited: Baidu(10)
Water use, growth and yield of green gram under rainfed upland crop sequences in Gangetic Plains of Indian sub-tropics
A. Zaman, S.K. Choudhuri
Journal of Geographical Sciences    2002, 12 (3): 301-304.  
Abstract984)      PDF(pc) (124KB)(56)       Save

A field experiment was conducted to study the effect of different crop sequences on water use, growth and yield of green gram (Vigna radiata (L) Wilezek) during 1992-93 and 1993-94 under rainfed upland condition in Indo-Gangetic plains of West Bengal. Green gram sown in the month of March as pre-rainy (summer) season crop, as and when the winter crops vacated the land, produced highest dry matter of 372 gm-2 which was significantly highest in black gram-yellow sarson sequence. The results of the field experimentation revealed that green gram gave highest grain yield to the extent of 10.80 q/ha when sown after black gram (rainy season) followed by yellow sarson (winter season) while the crop produced 10.63 q/ha under sesame-yellow sarson sequence. Highest water use of 267 mm was achieved in green gram under black gram-yellow sarson sequence and the crop gave water use efficiency of 4.07 kg ha-1mm-1 under black gram-yellow sarson sequences.

Related Articles | Metrics | Comments0
A new conception on the formation of the first bend of Yangtze River: its relations with Eocene magmatic activities
ZENG Pusheng
Journal of Geographical Sciences    2002, 12 (3): 305-312.  
Abstract813)      PDF(pc) (359KB)(60)       Save

Based on field observations, the author proposes a new understanding on the formation of the first bend of the Yangtze River. The relationship between the formation of the first bend of the Yangtze River and Eocene magmatic activity is expounded, suggesting that the first bend of the Yangtze River is the result from choking of the strong magmatic activity in Eocene. As a result, the upstream became a natural reservoir, whose riverside between Mt. Yulong and Mt. Haba was burst, guiding Jinshajiang River running eastward. At the same time, the drastic uplift of the Qinghai-Tibet Plateau led to the deep dissection of the river cut down the channel, resulting in the formation of the Tiger Leaping Gorge. The magnitude of uplift in the study area (located in the eastern of the Tibetan Plateau) is calculated. Taking Mt. Yulong as a base, the magnitude of lift is 3,300 m from Eocene to Pliocene, adding 700 m since Pleistocene, totaling up to 4,000 m or so.

Related Articles | Metrics | Comments0
Cited: Baidu(4)
The application of GPR to barrier-lagoon sedimentation study in Boao of Hainan Island
YIN Yong, ZHU Dakui, TANG Wenwu, Martini I. Peter
Journal of Geographical Sciences    2002, 12 (3): 313-320.  
Abstract1042)      PDF(pc) (708KB)(68)       Save

Sedimentary successions and internal structure of the coastal barrier-lagoon system of Boao, eastern Hainan Island were studied through utilizing data from test holes and trenches and ground-penetrating-radar (GPR) profiles. During late Pleistocene, fluvial and delta plains developed over an unevenly eroded bedrock during low sea level stand, followed by the formation of littoral and lagoon facies and defined coastal barrier-lagoon-estuary system during the post-glacial uppermost Pleistocene-lower Holocene eustatic rise of the sea level, and the upper Holocene high stand. GPR results show that Yudaitan, a sandy coastal bar backed by a low-laying land (shoal) just east of the active lagoon, is a continuous, parallel and slightly-wavy reflectors indicating homogeneous sandy or sandy gravel sediments, and inclined reflectors partly caused by progradation and accumulation of beach sand and gravel. Quasi-continuous, hummocky and chaotic reflectors from the shoal of Nangang village correspond to mixed accumulation of sands and clay. This research indicates the GPR is a non-intrusive, rapid, and economical method for high-resolution profiling of subsurface sediments in sandy gravelly coast.

Related Articles | Metrics | Comments0
Cited: Baidu(8)
Assessment of biochemical concentrations of vegetation using remote sensing technology
DING Shengyan, GU Jidong, QIAN Lexiang
Journal of Geographical Sciences    2002, 12 (3): 321-330.  
Abstract725)      PDF(pc) (310KB)(56)       Save

The main biochemicals (such as lignin, protein, cellulose, sugar, starch, chlorophyll and water) of vegetation are directly or indirectly involved in major ecological processes, such as the functions of terrestrial ecosystems (i.e., nutrient-cycling processes, primary production, and decomposition). Remote sensing techniques provide a very convenient way of data acquisition capable of covering a large area several times during one season, so it can play a unique and essential role provided that we can relate remote sensing measurements to the biochemical characteristics of the Earth surface in a reliable and operational way. The application of remote sensing techniques for the estimation of canopy biochemicals was reviewed. Three methods of estimating biochemical concentrations of vegetation were included in this paper: index, stepwise multiple linear regression, and stepwise multiple linear regression based on a model of the forest crown. In addition, the vitality and potential applying value are stressed.

Related Articles | Metrics | Comments0
Cited: Baidu(4)