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  • 2005 Volume 25 Issue 2
    Published: 20 March 2005
      

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  • FANG Xiu-Qi, YE Yu, GE Quan-Sheng, ZHENG Jing-Yun
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    The development of town system may be used to indicate the land exploitation in the Northeast China during the Qing Dynasty because the towns were set to be the location of the administrations such as counties, districts, or provinces that managed the farmers who exploited the land.There were four phases in the course of town system development during the Qing Dynasty when the towns were set quickly in the Northeast China, which indicated there were four times tidal waves of land exploitation.The town system expended spatially from the south to the north, and from the middle part along the Shenyang-Jilin, Changchun Harbin to the east and the west parts of the Northeast China, corresponding to the four fast increased phases in town numbers, which indicated the exploited area jumpingly extended from the south to the north.And the land exploitation in the Northeast China Plain was earlier than other sides, which is similar to the evolvement of town system.It shows that the land exploitation is limited and affected by natural area’s conditions, landform and policy.
  • LIU Ji-Sheng, CHEN Yan-Guang
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    In this paper, the relationship between urban population size and land area of urbanized area of Shandong Province, PRC, in 2000 by is analyzed means of the fifth Census data.Without an accepted definition of urbanized area in China, we define the urbanized area by means of variable thresholds and two lower limit values are adopted: one is about 500 person/km2, and the other is around 600 persons/km2, taking into consideration the scale invariance of urban form.The system of cities is divided into three cases: first, larger cities without the towns of counties;second, the towns based only on counties;third, whole cities including both larger and smaller ones.Four simple functions in common use are tested:① linear, A=a+bP;② exponential, A=aexp (bP);③ logarithmic, A= a+blnP, and ④ power, A=aPb.Where A represents the urbanized area, P denotes the population in the corresponding urbanized area, both a and b are parameters regarded as constants under given conditions.Among the four functions, the power, which is most widely used in the literature on fractal and self-organized criticality, fits best for both the data based on different thresholds without considering the counties.However, if the smaller cities based on counties are taken into account, the results make a difference and then the logarithmic one fits better than the power.This implies that only the larger cities in Shandong Province conform to the law of allometric growth.The cause that the smaller ones fail to obey the law can be explained demographically: the data are not based on cities strictly but on districts for administrative purposes.The scaling factor of allometric model,b, is computed such as b =0.711 and b=0.794 for different thresholds, negative allometry results implying that A increases at a slower rate than P.In addition, the data based on non-agricultural population and built-up area are also fitted into the power function, which gives the allometric coefficient as b =0.854 <1, a negative allometry result still.Although the statistical results of the allometric equations in some cases are not satisfactory, we can still draw a clear conclusion that the Shandong urban system is rational state where the urban area-population relationships are concerned.The suggestion is made that self-organizing theories can be employed to optimize the urban system in the studied area.Sometimes the allometric relationships retrogress from the power to the logarithmic one, just as it does in Shandong systems of cities.This phenomenon is interpreted theoretically in the light of mathematical transformation.As a matter of fact, if we suppose that the growth rate of urbanized area is restricted without reason, the allometric equation will inevitably change into the reverse-exponential relationships.
  • FENG Jian
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    The author selects 10 districts of Beijing and try to investigate the cognitive maps of urban residents in Beijing by questionnaire.He get 323 cognitive maps, which are classified and counted, and as a result, correlative statistical data are obtained.Based on the above-mentioned work, the author analyzs the basic types, constitutive factors, development phases and the characteristics of differences of cognitive maps of urban residents in Beijing.The research shows that although the types of spatial cognition of Beijing’s residents are similar to those of the western cities of China, they are a little different.The grades of cognitive maps are concerned with residential area, sex, educational level, income and birthplace of urban residents.The constitutive factors of cognitive maps are concerned with residential area, age, income and birthplace of urban residents, while the development phrases are concerned with sex, income and birthplace of urban residents in Beijing.The research also shows that social role and economic income level play important roles in the development phrases of spatial cognition of Beijing’s urban residents.At last, the author generalizes the spatial structure of Beijing’s urban image based on the location and frequency of elements recorded on the cognitive maps of urban residents, and find that it is similar to the emphases of spatial distribution of Beijing.As a result, some theories of urban image of Lynch are proved in Beijing.
  • FANG Zhong-Quan
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    The development strategy of "extending to east and opening up to south" which cancelled northern groups has scientific meaning of "eco-city" and landscape ecology control.Its scientific values are embodied by the function of Baiyun District, which is constructing ecologic supporting system of economic development of the metropolis and big scale background, embodying the practical meaning of eco-economy and the development idea of constructing landscape city for Guangzhou.However, the economic development of Baiyun District is weaker than that of other districts of Guangzhou, and its urbanization level is lower, which is not according with the status as and administrative area of Guangzhou.The change of development focus weakened the superiority of Baiyun District, and the production factors of talents, capitals, techniques etc.are flowing to southeast.So, Baiyun District confronts double challenges of controlling and development.According to the district characters, plight and function, this paper suggests to settle the conflict of controlling and development through constructing three blocks, forming industrial groups, building ecologic residential districts and corridors.
  • LEI Jun, ZHANG Xue-Yan, WU Shi-Xin, ZHANG Xiao-Lei, LU Qi
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    The paper, based on remote sensing, GIS and Landsat TM digital images and the methods of spatial analysis and statistical analysis, analyzed the spatial-temporal characteristics of the rural-urban construction land use changes in Xinjiang from the end of the 1980s to the end of the 1990s.The primary findings show as the fowlling: 1) The rural-urban construction land use has been increased in many area.The expansion speed of the urban land use has been accelerated during the 10 years.The sub-land use changes of the rural-urban construction land use are characteristics by conspicuous regional differentiation among the three main region and among the 85 counties of Xinjiang.2) The change of rural-urban construction land use is mainly transformed from cultivate land and grassland.At the same time, the change of each kind of land use is characteristics of conspicuous regional differentiation.3 ) The force of rural-urban construction land use changes in Xinjiang is still the expansion of urban land and the rural settlement land, undoubtedly affected by the natural environment and social and economic conditions, which is main in the population increasing, GDP development and the third industry improvement.
  • SUN Feng-Hua, REN Guo-Yu, ZHAO Chun-Yu, YANG Su-Ying
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    The air temperature data used for the study come from six weather stations in Northeast China from 1905 to 2001.These stations all have temperature observation records for about 100 years, which include Shenyang, Dalian, Yingkou, Changchun, Harbin and Qiqihar.The average temperature time series for the areas are obtained by simply averaging the six station values in the period.In order to check the representation of the series, correlativity between the six station time series and the twenty-six station time series is made, and it shows a very significant correlative coefficient.The temperature time series were further analyzed for the changes on varied time scales in the area.It is found that a marked warming occurred in the area over the past 100 years, with the wanning much more obvious in winter than other seasons.A slight cooling trend in summer can be detected, though temperature in warm season began to rise after 1995.Spectrum analysis indicates a 2.3-year period and a 4.2-year period for the average temperature series.In addition, climate jumps for annual mean temperature are also checked by applying the Mann-Kendall and Yamamoto methods, and two significant jumps in temperature time series have been detected in the beginning of 1920’s and the late 1980’s.
  • TANG Yun, WANG Hao, YAN Deng-Hua, WANG Shui-Sheng
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    By applying ARCGIS8.3 as a key data processing platform, this paper analyzes the spatial-temporal differentiation of precipitation within a duration of 50 years (1951-2000) in Northeast China.The mean annual precipitation in Northeast China is 489mm, successively decreasing from southeast area to northwest area, which is 635mm, 481mm, and 355mm, respectively, in the east, central, and west regions.Another prominent feature of precipitation in Northeast China is its periodicals, with a period of 11 years in the east and west area, and 32 years in the central area.
  • LI Xiao-Qiang, ZHAO Hong-Li, YAN Min-Hua, WANG Sheng-Zhong
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    The records of charcoal and pollen from peat section at Qindeli, NortheastChina help us to reconstruct the fire variation and the vegetation history in the Holocene at Sanjiang Plain and to study their relationship among fire, vegetation and climate.The reconstruction of fire history also discusses the human activity of fire and the impact on environment.Two peak values of charcoal concentration appeared in the two periods of spares forest and grassland (9 200-8 500 a B.P.) and spares forest (9 700-9 200 a B.P.) corresponding to two climate epochs of warm-dry and relatively warm-arid respectively.In the wet period the charcoal concentration shows the low values.The frequency and intensity of fire are high in the dry period and low in the wet period.However, the characteristic of vegetation and the types of plant also restrict the frequency and intensity of fire in the Holocene at Sanjiang Plain.In the mean time, the exploitation to Sanjiang Plain influenced the fire variation and environment greatly after the 1950s.
  • SHI Chang-Xing
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    With a high sediment load, the lower Yellow River has been aggrading rapidly for a long time.The causes of the aggradation became a hot topic among Chinese scholars in recent decades.Opposite opinions on the issue were raised.Some attributed the aggradation mainly to base level control, and some others associated it mainly with watershed control.Changes of base level control in the lower Yellow River are caused by the extension of the river mouth.This study reveals that different opinions on the issue were advanced because the issue was investigated on different time scales and some impertinent methods and evidence were employed by some previous studies.A certain time scale is necessary for studying this issue because there exist complex and constant changes in upriver inputs, mouth extension, and other factors influencing the sedimentation in the lower Yellow River with time as well as the hysteresis of channel adjustment of the river to these changes.A period of tens to hundreds of years seems to be a proper and practical time scale on which to discuss the issue.In order to back up the argument that the aggradation associated with base level control dominates in the lower Yellow River, some previous studies try to prove that the slope of the lower Yellow River is large enough for transporting the sediment inputs if the river mouth does not extend or that the aggradation in the river takes the form of headward aggradation.However, the author finds that all the evidence provided by those studies for this argument is untenable.The change in water level or deposits thickness along the river in a period is among the evidence.In piece of telling and concrete evidence, it has a good performance in determining the effects of base level control on aggradation on many other rivers, but the existence of great yearly variations of upriver inputs and concomitance of aggradation due to upstream and downstream controls in the lower Yellow River make it unsuitable in this case.As a fact, this evidence was also used by some other studies to claim the dominance of aggradation due to upstream control.Moreover, through flume experiments or calculation based on hydraulic models some studies disclose that the slope of the river is much lower than the graded slope under the current upstream inputs even if the river mouth does not extend.The methods and evidence used by studies to support the argument that the effect of base level control on aggradation has been limited in a reach close to the river mouth are also examined and disproved.Thus, both the arguments that the aggradation in the lower Yellow River has been dominated by the base level control and that the effect of mouth extension has been limited in a reach close to the river mouth for all time scales are not acceptable.
  • ZHANG Xin-Ping, TIAN Li-De, LIU Jing-Miao, YAO Tan-Dong
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    The variations of stable isotope in precipitation along three vapor transport path are analyzed and compared.Along the south vapor path that is from the equatorial areas through the southwest vapor passage in the Yunnan-Guizhou Plateau towards to the mid-lower reaches of the Yangtze River, the seasonal differences of mean δ18O in precipitation are small in the sampling stations located in low latitudes, but increase from Bangkok toward north.The δ18O values in precipitation fluctuate on the whole, showing the different vapor origins.The appearance of the minimum δ18O at Kunming is related to its high altitude.Along the north vapor path from west to east under westerlies, the seasonal differences of the mean δ18O in precipitation, between the warm and the cold half-year, are all greater than zero for the stations in the west of Zhengzhou, and then decrease with the increasing longitude.During the cold half-year, the mean δ18O in precipitation reaches its minimum in Urumqi with the minimum temperature, influenced by the wide Cold-High Pressure over the Mongolia, then increases with longitude gradually and keeps at a roughly same level from Zhengzhou towards east.However, the δ18O values in precipitation are lower in the east than in the west during the warm half-year, influenced by the summer monsoon o-ver East Asia markedly.Along the plateau path that is from the tropics through the Indian Subcontinent and the Himalayas to the northern Tibetan Plateau, the mean δ18O values in precipitation are correspondingly high in the south parts of the India Subcontinent, and then decrease with latitude gradually.A sharp depletion of the stable isotopic compositions in precipitation takes place due to the very strong rainout of the stable isotopic compositions in vapor in the process of the lifting on the southern slope of the Himalayas.The δ18O in precipitation is kept at a low level from Nyalam to the Tanggula Mountains during the rainy season all the while, but increases with increasing latitude persistently from the Tanggula Mountains to the northern Tibetan Plateau because of the replenishment of vapor with the relative heavy stable isotopic compositions originating from the inner Plateau.The situation in the dry season is different: the mean δ18O values in precipitation decrease basically along the path from south to north.Generally, the mean δ18O in precipitation during the rainy season are lower than in the dry season for the regions controlled by the monsoons over South Asia or the Plateau, but contrary for the regions without monsoon or by weak monsoon.
  • GAO Hong-Shan, PAN Bao-Tian, WU Guang-Jian, LI Ji-Jun LI Bing-Yuan, DOUGLAS Burbank, YE Yu-Guang
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    Based on field investigation, we find that the rivers generally developed 5-6 terraces in the east Qilian Mountains during the Quaternary.According to the ESR (Electron spin resonance), TL (Luminescence), IRSL (Infra-red stimulated luminescence) and 14C dating methods, the ages of the Jinta River terraces are 1.24 Ma B.P.(T5), 0.78 MaB.P.(T4), 0.14 Ma B.P.(T3), 0.06 Ma B.P.(T2), and 0.01 Ma B.P.(T1)from up to down.The Xiying River developed 6 terraces near the Xiying Reservoir, some ages are 0.84 Ma B.P.(T6), 0.25 Ma B.P.(T4), 0.14 Ma B.P.(T3), 0.06 Ma B.P.(T2).These terrace sequences can be roughly correlated with the stepped landforms found in upstream Yellow River and Yangtze River watersheds.After careful analyses on the ages of gravel bed accumulations and the ages of channel down-cuttings, we propose that climate variations play significant roles in controlling river terrace evolutions even within the tectonic active regions.
  • HAN Xiao-Zeng, WANG Shou-Yu, SONG Chun-Yu, QIAO Yun-Fa
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    Black soils, located mainly in Heilongjiang and Jilin provinces of China, cover a broad area from 43皌o 48癗 and from 124皌o 127癊, with a total area of 5.93?106 ha.The black soils were cultivated about 200 years in south, 50 years in north and 100 years in central parts of the black soil area.These soils are one of the most fertile soils in China.These soils were cultivated for a relatively short time as compared to the soils in southern China.The vegetation changed from natural vegetation to crop-weed, to rotation of corn-soybean-wheat, or to rotation of corn-soybean.Steppified herbosa were flourished in black soil area under the proper weather condition for plant growth where the precipitation of about 500mm to 600mm mainly from April to September is synchronized with heat.The water status has changed dramatically with the use of land.If we take the water storage in the depth of 1m in spring in natural soil under the Steppified herbosa vegetation as control, the water storage under crops decreased to 20.4%, 20.6%, 22.6%, 27.2%, 29.3%, 27.3% after 2, 8, 15, 30, 50, and 100 years cultivation, respectively.The decrease of water storage was around 17.6% to 30.8% in summer investigation and about 19.7% to 29.9% in autumn measurement.According to the data from the three times measurement, we make a simulated calculation.The result showed that, the storage of water in this area was as high as a 24.9?109t reservoir in spring.The storage of water has decreased to 19.2?109 t after a hundred year cultivation.The impact of land use/cover on the soil water status is great.The capacity of land for storing water is decreased by 20% when cultivated for crops in contrast to natural soil.After the second year when the land was initially cultivated, the capacity decreased 6.9% every year with the cultivated time.So we concluded that the effect of soil use/cover is bigger than the time effect.The effect on black soil C pool of land use method and land cover is decisive, the C pool has a increase trend under original soil condition and steppified herbosa, it will decrease when black soil were reclaimed from its original state to farmland covered with crops.Compared with the capacity on soil C pool in 1 m soil layer under original soil condition and steppified herbosa, however, the organic C pool were decreased slowly by 23.71% on farmland after cultivation of 100 years.Plants need nitrogen as a macro-element.Method of land use and land cover affected the N pool in black soil in the same trend as for the C pool.Nevertheless the change in C pool in the layer from 50cm to 100cm is not significant in the period of 100 years;it is expected that much longer time is needed to have a significant change.It is land use/cover that makes tremendous influence on water and soil losses, but there is a litde relationship of water and soil losses with the cultivation time.Compared with the original soil and natural vegetation, the annual water loss of reclaimed farmland increased 27t/( ha·a);and there are as much as 50.93?106 t of water loss for the whole black soil area.Also the annual soil loss of reclaimed farmland increased about 38 t/ha;and there are 78.87?106 t soil loss for the whole black soil area.The over-cultivation not only resulted in the soil and water loss but also deteriorated the human living environment.
  • ZUO Wei, WANG Qiao, WANG Wen-Jie, WU Xiu-Qin, YANG Yi-Peng, YANG Li-Jing, ZHU Xiao-Hua
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    Regional ecological security assessment can be attained by assessing model, the establishment of which has to overcome theoretical, technological, methodological, data difficulties.According to the essential characteristics of ecosystem, the paper optimally compounds the comprehensive models of regional ecological security assessment such as hierarchical analysis, gray system, fuzzy mathematics, variable weight, etc., thus a-chieving the assessing conclusions which closely reflects the real situations.In this paper, the composite models of hierarchical analysis-variable weight-fuzzy-gray correlation are constructed and used as the assessing model for regional ecological security.The case study here shows that this model is the relative best one for regional ecological security assessment at the current stage and conditions.
  • REN Li-Jun, SHANG Jin-Cheng
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    Industrial structure decide the economic benefit, the resources utilizing efficiency and the pressure on environment of a region, so the assessment of industrial structure rationality is very important.This paper establishes the indicators system of the ecological rationality assessment of industrial structure.The assessment indicators system comprises 17 indicators that reflect the present situation of economy and society, the utilizing rate of resources, and the situation of environment.The criterion of assessment includes five grades.Then, the paper applies the fuzzy mathematics evaluation method, and assesses the ecological rationality of industrial structure in different regions in Shandong Province.The results of different regions and systems are compared and analyzed.On the whole, the present situation of economy and society is not very good, the utilizing rate of resources is low, and the environment is facing serious challenge in Shandong Province.The assessment results prove the ecological rationality of industrial structure of the whole province belongs to Ⅲ grade.The industrial structure’s impact on the assessment conclusion of ecological rationality is discussed.At last, the paper puts forward some basic countermeasures to optimize industrial structure and to promote the sustainable development in Shandong Province, such as decreasing the proportion of primary industry and transferring the large number of people of farm to secondary and tertiary industries, reforming the traditional industry and trying to develop the high-technology industry, increasing the proportion of tertiary industry.
  • FENG Song, ZHANG Yong-Jun, ZHU De-Qin, TANG Mao-Cang, GAO Xiao-Qing
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    Using the Guliya ice core accumulation from 1951 to 1991, and the precipitation data in south part of the south Xinjiang basis form 1951 to 2000, and the NCEP/NCAR reanalysis data of atmospheric circulation from 1958 to 2000, their correlation have been discussed and their mechanism also have been analyzed.Based on these analyses the high resolution of the dry and wet change sequence in the past 2000 years was established.
  • MA Yan-Ji
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    Study on regional industrial agglomeration is an important aspect of human geography.It is important even in the study of regional system of human-land relationship.Since the 1970’s, some important theories were developed, including new industrial district, new economic geography, and competitive advantage of nation and diamond theory.LU Dadao’s theory of Pole &Axis system was the important basis of nation and region’s industrial distribution.In Li Xiaojian’s theory of company geography, many important methods were given on study of enterprise.Many scholars analyzed the mechanisms of industrial agglomeration, mainly on agglomeration economy, trade and market, enterprise linkages, knowledge communication.In China, indexes of industrial agglomeration and FDI were studied specifically, and industrial cluster was the focus.Case studies are mainly on the cities or regions in Southeast China and Beijing.New industry and labor-intensive industry are mainly selected.In China, as a response to globalization and foundation of socialist market economy, it is helpful for the reconstruction of old industrial bases, also it is a key problem in studying regional industrialization and urbanization.Using for reference of theories and practices of studies on regional industrial agglomeration at home and abroad, we should studied the theory of regional industrial agglomeration systematically.The study includes mechanism and laws of industrial agglomeration, relation of industrial agglomeration and regional development, conversion and controlling of regional industrial agglomeration.Some researches should be done on the industrial agglomeration in old industrial bases, including conversion and controlling of regional industrial agglomeration, fostering of multinational corporation and industrial cluster, coordination among the areas in or out industrial agglomeration body.In addition, when cultivating the industrial agglomeration, regional sustainable development should be emphasized.
  • ZHU Qiu-An, ZHANG Wang-Chang, ZHAO Deng-Zhong
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    The spatial interpolation of monthly and daily precipitation over the Heihe region in the middle range of the Hexi corridor was systematically studied, and a new methodology based on PRISM approach in association with the utilization of Thiessen polygon analyses to counter the problems existed in daily precipitation spatial interpolations was proposed and validated with the meteorological data obtained in 1988 from 28 stations in the study region.In order to upscale the precisely interpolated yearly or monthly precipitation results derived from PRISM applications to the daily ones in the study region, a transferring algorithm was developed based on the fact that spatial regime of the specific day’s precipitation in the specific month is generally similar to that of the monthly precipitation spatial patterns of that month under study except some difference for some specific locations without precipitation in daily precipitation spatial distributions.For accurately locating the area where no precipitation take place in specific days over the study region, Thiessen polygon approach was utilized to determine the probability of daily precipitation in each pixels.The performance of the proposed methodology was validated for 6 stations, and the derived daily spatial precipitation over the study region was statistically analyzed in both temporal and spatial scales.The detailed analysis indicates that the method is simple and reliable and is able to meet the precision need of the distributed daily precipitation in the distributed hydrological process studies or relevant distributed land surface process simulations.
  • GU Wei-Wei, ZHU Cheng
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    This paper discusses the spatial-temporal distribution of Neilithic sites and the relation with environmental variation, that is, climate and sea level change in North Jiangsu Province.Since the 1980s, Chinese scholars have made a lot of research on the relation between the spatial-temporal distribution of Neilithic sites and the Holocene sediment stratum,transgression, coast evolution,and get lots of achievements.However, the correlative research on the spatial-temporal distribution of archaeological sites, stratigraphy and micropaleontology are few.North Jiangsu Province, the most important part of Jiangsu Plain, has vast area, dense river, warm climate, abundant rain fall, and is one of areas with the clear-cut prehistoric culture series and prevailing Neolithic culture during 7.0-4.0 ka B.P.based on many archaeological finds.The Neolithic culture series that includes Qingliangang culture, Liulin culture, Dawenkou culture and Longshan culture has been established basically.There are 58 culture sites in total in North Jiangsu Province.The number of Qingliangang culture sites reaches 18, accounting for 31.0% of total sites.The number of Liulin culture sites is 9, being 15.5% of total number of culture sites.The number of Dawenkou and Longshan culture sites is 8 and 23 respectively.Qingliangang culture sites are mainly located on the plain from Siyang to Lianshui along the abandon Yellow River.Liulin culture sites are mainly located on Lianshui, Pixian, Gaoyou and so on, and there is no culture sites found around Hongze Lake, Liulin culture sites decreased sharply.Dawenkou and Longshan culture sites are mainly located on the west of Lianyungang, Shuyang and Sihong, the number of culture sites increased greatly.The distribution of prehistoric culture sites is limited by environment, and has internal and exterior law.According to correlative research on the spatial-temporal distribution and geomorphology, the authors draw the conclusions as follows: The distribution of above culture sites has close relation with climate and sea level change.Prior to 7000 a B.P., the largest Holocene transgression invaded North Jiangsu coastland, so there are no Neolithic sites found in this area.During 7.0-6.5 ka B.P., the climate was warm and wet, Qingliangang culture become flourishing, the archaeological sites are mainly located on the land, where does not be affected by Holocence transgression.During 7.0-6.5 ka B.P., terrestrial area reduced and the number of Liulin culture sites decreased sharply, it indicated the arrival of Holocence high sea level around 5.5 ka B.P.in North Jiangsu Province.During 4.1-3.8 ka B.P., the climate was mild and dry, sea-level was fall-off and terrestrial area enlarged.Most of North Jiangsu area became dry land, it made Longshan culture developed well, the number of culture sites increased greatly.Therefore, the above variation of geomorphology evolution and hydrology affected succession of archaeological culture types greatly, that is, culture developed and number of sites increased with trend of transference to low lands owing to warm and dry climate and higher terrain suited to habitation.On the contrary, the warm and wet climate enlarged water area and went against the development of ancient culture showing few cultural sites.
  • ZENG Fan-Wei, XU Gang, LI Qing
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    The investigations on 21 debris flows on mountain slope in Beibei District, Chongqing makes clearly that gradients are very important to debris flow on mountain slope.After counting and analyzing a great deal of the drainage area of debris flow on mountain slope, we find that the distribution of gradients is the normal distribution.According to the distributive laws of the average gradients of the drainages areas of debris flow on mountain slope, we make sure that the critical gradients can be classified into three kinds.The average of the first kind of the critical gradients is 32.4 degrees.The debris flows belonging to the first kind of the critical gradients are apart from residential areas and human being’ activities are feeble, and at the same time, their vegetation rates are higher.The average of the second kind of the critical gradients is 27.3 degrees.The debris flows belonging to the second kind of the critical gradients are located in woodlands and farmlands, and human being’ activities are acute and the vegetation rates are lower .The average of the third kind of the critical gradients is 36.8 degrees.The debris flows belonging to the third kind of the critical gradients are in the Guanyin gorge.They are controlled by the terrain condition.We have quantitatively explained the relationship between the crucial gradients and the debris flow on mountain slopes.It can afford services to the dividing ecological frailty sections, engineering construction, preventing and decreasing disasters, and the government decision-making.
  • ZHANG Jin-He, ZHANG Jie, LIU Ze-Hua
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    Tourism field is a basic existence of tourist activities, which has energy, momentum and quality, operates and affects on the generating, centralizing and expanding of tourism flows, reflects the interaction relationships among the different places in tourism field.This paper offers an analysis model of spatial competition among tourism regions based on the theory of tourism field and a conceptual system of tourism field.It puts forward an idiographic analysis method of tourism field from three aspects, namely the intensity of single place, potential energy of several places and interaction among many places in tourism field.It takes the tourism region of South Anhui as an example, by using the theory and methods of tourism field, discusses the general character of tourism nucleus, hierarchic structure of tourism field, hierarchic structure of tourism flows spreading and spatial behavior of tourism flows in tourism region of South Anhui.Finally, this article draws some basic principles of spatial competition among tourism regions and discusses the use of the theory of tourism field.