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  • 1994 Volume 49 Issue 1
    Published: 15 January 1994
      

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  • Yang Wuyang
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    The transformation of Beijing’s retailing and services center and relevent network underwent four generations:1. Dadu (as the capital of Yuan dynasty) was planned according to an ancient code <>which stipulated that. the imperial courts should occupy the city core and the marketing places could only be located backward. So the main Commercial district of Dadu was situated betwen the central point. Grand Canal tail and "Bell and Drum Towers".It was the first generation of retailing and servises center of Beijing. 2. During Ming and Qing dynasties. Beijing’s city walls got some changes. The city trade center moved from the Towers Bazaar to the Front-court and then to Qianmen. When an outer city surrounding the Tributary marketing areas was built up.Qianmen began to be Beijing’s retailing and services center of the second generation. (3) At the end of Qing Dynasty and Republic of China. owing to the Dongjiaomin lane was opened up for foreign diplomatic corps. Wangfujing street soon became flourishing and became another retailing center of Beijing. So as to Beijing was from a single center to twin ones. which formed the third generation of Commerce.As a regional or countrywide commercial center. Beijing has gone thorugh 760 years. Since the establishment of P. R. China. Beijing’s areal structure of commercial activities has occured gigantic changes due to the growth of population. the extension of metropolitan area, the improvement of road network and communication facilities etc. . The author is engaged in Beijing’s retailing and services study over ten years. His principal discoveries are as follows: 1 . The retailing and services center and network of Beijing city. no matter when or where. in addition to the Forbidden city occupying a central position. fully accords with Christaller’ s central place model. To be sure. the present hexagonal structure of Beijing’s trade distribution is more perfect than the past ones. 2. Accompanied by the prolongation of Changan Street. a new force suddenly coming to the fore──that is the rise of Xidan business district. Since the middle of 1960s. Xidan became another new municiple trade center in addition to Wangfujing and Qianmen. Three high-level centers constituted a city core or CBD triangle of the metropolis which center on the Tian An Men Square. This triangle made up a situation of tripartite confrontation and formed the second special case of Beijing’s down town of the fourth generation.At the end of this paper, the author would like to introduce his prediction on Beijing’s commercial center for next century. The basic points are Beijing will possess an unitary commercial center (CBD) at the beginning of 2000s and the rational location of the newly CBD should be Xidan inevitably. This conclusion is drawn by:1. Xidan is situated the center of the planning region──a roughly circular area of 750-900km2. Moreover. the accessibility of Xidan central place is higher than that of any of the others inside the city.2. The author initiated making use of the Varignon’ s theorem in order to inquire into the urban central point considering residential distribution.The author had some people solve above mentioned simultaneous equations and obtain the Varignon’s center of Beijing metropolis from the data of 112 zonelets. This center drops onto Gangwashi. to the north of Xidan crossroad only 1. 2km. which is becoming one of the components in Xidan trade district. By the way, the gravity center of Beijing is situated to the northwest of Xidan 2.3km.3. The external transportation is a decisive factor for the growth of any metropolis, especially for a state capital. Beijing has already been the general hubs of railroad and airline network in China.Its floating and temporary population surpasses 1000 thousand. most of whom come via railroad terminals. There exist three passenger rail stations in the metropolitan region Beijing Station. Beijing South Station and Beijing North Station. A bigger passenger terminal──Beijing West Station will be built up in 1990s. The author 
  • Chen Shupeng
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    During August 6-11, 1993, Beijing hold a Chinese Map Exhibit which revealed the history of Chinese map development. achievements in recent half centry and potential market need. The Exhibition was a great success. It contributed considerably to the social understanding of map making. As a matter of fact. the ultimate products of almost all kinds of traditional result of geo-scientific researches and surveying and mapping are without exception maps.And they are not limited to topographic maps only. Development and production of thematic map have become a huge trans-departmental, trans-professional and trans-regional scientific complex and systems engineering. from which Chinese cartographers draw promptly great enlightment in so many aspects: i. Market economy needs maps to be more practical. Publication volume of teaching maps,tourist maps. postal maps and traffic maps tends to be great. Social development and economic construction strongly need reducing period of map revision and production and suiting the deve lopment of high techs such as satellite communication and optical fiber cable network for data communication. Chinese cartographers are striving for new map products which are based on global positioning system (GPS) information sources from satellite remote sensing and geographical imformation syttems (GIS). Chinese developed computer editing and printing system for thematic map may reduce the cost of map production by 60% and period of production 50%.ii. Cartography should not only keep abreast of the highly developed information society of space science and technology but. at the same time. response to the programme of action for the <<21st Centry Course>>and provide timely information service for the sustainable development of regional social economy. Macroscopiaclly.cartography should provide the ultimate maps and data.which assist decision making. for geo-stratigic research, regional planning and management. while microscopically. provide trend forecasting basis for evironmental engineering and geo-technological design. In recent ten years. Chinese cartographers have compiled and published many trans-professional, trans-departmental and trans-administrative area regional maps and atlas in which much attention was given to the unity of social benifit. economic benifit and ecologic benifit. may be made a great contribution to the world in the research on sustainable development of regional social economy and global environmental change.iii. A kind of man’s cultural tools and "the second language of geo-science" as it is called. map should in deeply explore it’s new function of scientific" thinking" .esp. its multi-dimentional analysis function in the research on temporal and spatial role and its development. The author lays stress on further permeation between cartography and cartography related sciences such as geo-sciences. biosciences. space sciences and information sciences. Today. with great abundances in earth observation information sources. cartographers are required to make thorough researches. discarding the dross and selecting the essential, eliminating the false and retaining the true. proceeding from the phenomina to the role and proceeding aspect from this one to another. to extract the most effective information. to simplify it by cutting out the superfluous and to suit the need of social development and scientific research with high speed and quality. Now. in China. digrtalization. standardization and internationalization have basically been realized in map making in fields of geologic sciences. atmospheric sciences. geophysic sciences. seismology etc.analysis and forecasting models have been set up and researches on summarizing expert knowledge law and logical reasoning mechanism are being carried out. It is entirely possible that we through doing so forecast the earth’s future development according to the mechanism of evolution process of earth system and using multi-sourced information. Chinese cartographers are now actively and in time engaged themselves in researches on geo-informatics 
  • Wang Jingai, Shi Peijun, Zhu Li
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    According to distribution of 50 types of natural hazards all across the country. this article discusses types. percentage of covered area. as well as relative intensity of all these natural hazards in each county and the statistical units. Besides. we build a data base of 2265 counties all over the country and for 102 types or subtypes of natural hazards. Based on the data base, we produce maps of Distribution of Multiple Degree of Natural Hazards in China. Distribution of Relative intensity of Natural Hazards in China.and Distribution of Covering Index of Natural Hazards in China. We also analyse their regional distribution to support further research on regionalization of natural hazards in China.Three indexes are used in the article to express regional distribution of natural hazards. They are multiple degree. relative intensity and covering index of natural hazards.The article draws the following conclusions:a. Areas with poor natural enviromental conditions or ECOTONE must not have high multiple degree and relative intensity. Natural conditions in Guizhou, the most typical area. are poor. but they are not yet able to become natural hazards.b. Sensative zones of natural environmental evolution must not suffer from both high multiple degree and high relative intensity. For example, semiarid areas in northern China especially the combined area of agriculture and animal husbandry, are multiple hazard areas other than intense hazard areas. while Southwest China is intense hazard area with low multiple degree.c. Northern China has the highest multiple degree, relative intensity and covering index of natural hazards all across the country.d. According to the clear regional distribution of natural hazards in China. nine regions of natural hazards can be divided. which are Northeastern China Region. Northern China Region, combined Region of agricuiture and animal husbandry in Northern China. Northwestern China Region,Qinghai- Xizang Plateau Region, Southwestern China Region. Guizhou Platcau Region. Middle China Region and Coastal China Region. 
  • Zhang Houxuan, Zhang Yi
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    Active accumulated temperature is an important index of agriculture heat resource in a region. In future 2×CO2 scenario global climate will be warmer, and accumulated temperature and lasting days of china will increase. Because of simuteneous change of accumulated temperature and its lasting days after warming. the calculation of this problem is difficult. In this paper, a set of simple and practical formals are deduced based on the changing regularity of active accumulated temperature. We can take any form ouput data of GCM mean air temperature to calculate them, and the suitability is good. We also estimate the distribution of changing values of accumulated temperature Σ(≥0℃,≥10℃)and lasting days. The calculated results show that in the scenario of 2×CO2, the accumulated temperature and its lasting days will be increased. For example. the increment ofΣ≥0℃ accumuleted temperature △ ΣT0 in north China has a trend of gradual decrease along the latitudes from 430(℃ ·d) to 240 (℃·d). In the YianZi River valley,△ΣT0 will be about 430-490 (℃·d ), but in the south, △ ΣT0 will be constent -490 (℃·d). The increment ofΣ≥10℃ accumulated temperature△ΣT10 is about 320-810(℃·d), and also have a trend of gradual decrease along latitudes. But△ΣT10 decreases in the southern coastal area of China. The increase of accumulated temperature and lasting days will be a beneficial facter for expanding the multiply-cultivated-system area, and for increasing the multiply crop index in China. 
  • Luo Zhexian
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    The horizontal inhomogeneties of thermal and dynamic characters in the land surface induced by plant-bare soil zones whose space scale are 100-10l km can generate meso-scale circulation and change the local climate. In order to study the effect of the width of plant zone(d) on the meso-scale circulation and the local climate, seven numerical experiments (Ex1-Ex7) have been designed and performed by using a two-dimensional midel. Set d = 5, 7, 9, 11, 13, 15 km, respectively and Ug=2.5 m/s in Ex1-Ex6, where Ug denotes the basic zonal wind velocity, and set d= 9 km and Ug= 0.0 m/s in Ex7. The results are as follows:1. The effect of the width of plant zone on local temperature. A cold island over the plant-zone appears. The intensity of the cold island increases with the width. exhibiting a linear character ristic. 2.The effect of the width of plant zone on the maximum of vertical velocity. There is a most favorable value of the width dc, when d= dc, the intensities of the vertical cells, which are excited by the plant-bare soil horizontal inhomogeneties, achieve their maxima, exhibiting a nonlinear characteristic. 3. The influence of the basic flow on the vertical cells. It seems that the introduction of the basic flow into the model makes more intensive vertical cells. The investigation of the effect of the inhomogeneties induced by plant-bare soil zones on the local climate is a complicated subject.This work is an attempt in this field. Further study is needed to improve the model and experiments,and the work is just under way. 
  • Li Yuanfang, Zhang Qingsong, Li Bingyuan
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    Two cores of samples from Bangong Co and Sumxi Co and lacustrine sedimentary samples from one exposure near the Hongshan lake were collected. In order to obtain information about the environmental changes in the West Kunlun and Karakorum Mountains region since the late Pleistocene. detail analyses of ostracods have been carried out. On the basis of the distribution of ostracod fossils and their palaeoecological characters.it can be considered that a cold climate occurred beween 17 000 and 12 000 a BP, especially in the period 17 000-15 000 aBP. The runoff into the lake might slightly increase which infers a little warm up after 15 000 aBP. Assemblage character of ostracods and sedimentary features shows that the lakes in this area were slightly extended during the time of 12 500-12 000 aBP. No ostracod has been found in the strata in 11 500-10 000 aBP. This may correspond to the cooling event of Younger Dryas. When the Younger Dryas ended. the temperature rose rapidly, fine hydrological conditions for the development of ostracods appeared during the period about 10 000 aBP and 7 500-6 000 aBP which coincided with the rise of lake level and a warm-humid climate. Clinatic deterioration occurred since 6 000-5 500 aBP The water in the Bangong Co became slightly saline after 5 500 aBP. 
  • Pan Dingan, Wang Siming, Shen Huanting
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    Meizhou Bay is located on the coast of Fujian Province. There are many peninsalus, capes and islands. The submarine relief is more complicated. The Central Deep Channel is not only wide but also deep. The Central Deep Channel has three sections,which are the south sections, middle section and north section. Shoals usually develop along the coast or around the islands. Beiniu Sands is located in the zone where the south section and the middle section are connected in the Central Deep Channel. Tidal current is a major force to mould the submarine relief in the Meizhou Bay. To reveal the dynamic mechanism of the formation of deep channels and shoals, a numerical simulation of the flow field in Meizhou Bay is applied in this paper. The numerical model adopts Jan J. Leendertse’s geostrophic nonlinearity two-dimension flow field model. It is one of the major bases to analysis the formation of the Central Deep Channel and the Beiniu Sands. There are four-group peninsulas and islands in the Meizhou Bay, which can narrow the bay and control current action. The link line between the four-group peninsulas and the islands is a boundary line between the Central Deep Channel and the shoals. The major dynamics moulding the deep channel at the upper stream of the south section of the Central Deep Channel is the flood current. it belongs to the flood channel. At the lower stream the channel is moulded by ebb current, and it is an ebb channel. The middle section of the central Deep Channel is domained by ebb current, which is the major dynamics to mould the deep channel which is belongs to the ebb channel. At the north section of the Central Deep Channel. the major dynamics on the north shore is the flood current, and it is the ebb current which moulds the south shore. Thus,the evolution processes of the Central Deep Channel are different at various reaches. the dynamic mechanism can be divided mainly into three kinds including flood. ebb currents and combination of the two. In the Beiniu Sands area. there are a slow flood flow and a slow ebb flow. Therefore, the dynamics of the ebb flow is weaker. It is a place for sediments to be accumulated. which forms the basic conditions for the Beiniu Sands to form. The Beiniu Sands is located in the zone between the south and the middle sections of the Central Deet1 Channel.The dynamics in the deep channel of the south section is mainly the flood current.It extended in the direction of NW. The dynamics at the middle section is mainly the ebb current which stretches in the direction of SE. Althrough the trends of the two deep channels moulded by flood and ebb currents are the same, their locations are different. There are shoals between the two channels. Isobath 10 m at the SE of the Beiniu Sands is faraway from the islands, The ebb current is resisted in the middle section of the Centra1 Deep Channel which makes part of the Beiniu Sands like a spit.The flood current at the upper stream of the south section of the Central Deep Channel erodes the Sands. The isobath 5rn between the Beiniu Sands and the coastline is far away from the shore due to erosion. Therefore, the area where the depth is less than 5 m becomes a zonal isolated accumulation body. The returned current in the bay rounds the Beiniu Sands during the turning of tidal current, its duration is about 0.5-1hour. Sediments can be deposited on the shoals under the action of the returned current which is favourable to the evolution of the Beiniu Sands. The place with intensive sediment deposition is at the centre of the returned current.The head of the Beiniu Sands is always silting within 36 year, and the depth at the head of the sands decreased from 1.1m-0.3m since l954.The formation of the Beiniu Sands is n1ore complicated, and its evolution model is different from those in other places. 
  • Zho Shangzhe, Li Jijun, Pan Baotian and Zhang yechun
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    The source area of the Yellow River (33°-36°N. 95°-100°E. and higher than 430, on an average) is located in the east part of Qinghai-Xizang Plateau. Widespread glacial relics.such as streamlined landforms including roches moutonnees and whale back. glaciated troughs. smoothed hill tops, till deposits. qranodiorite erratics stria stones. kame deposits and so on. indicate that there was an ice sheet in this region during Pleistoene. The ice sheet covered an area of about 80000km2 and the centred of it is near the peak of Bayan Har mountain. south of which is the Changjiang drainage basin. Calculating by the equations H=3. 4L1/2and logv=1.23 (logs-1) (where H is thickness of centre of ice sheet. L is radius. V is ice volume and S is area). the thickness of the centre and the ice volume of the ice sheet were up to about 1360m and 63000km3 respectivily. We cna deduce that the glacier began to develop around the mountains and gradually covered all the area.The snowline of the modern glaciers on the Anyemagen Mountain, situated in the east of the area. lies at 5090m. and it was 4600m high during last glaciation and 4300m high during Penultimate ice age in the Ela Mountain, which is situated in northeast of the area. So we think that the ice sheet was developed not later than penultimate ice age when the plateau surface was much lower than that of today. and the snowline at that time was also lower than 4300m, Climatic data shows that. at present. the temperature is the lowest and the precipitation is relatively abundant in this area in the Qinghai-Xizng Plateau because of the influence of the monsoon. This is probably the reason why the ice sheet was formed only in this area but not in the west part of the plateau where the land surface is much higher. Some ice wedges developed at 135. 7±10.5 kaB. P. were found near Xinghai County (350m).which indicate that the mean annual temperature was approximately 10℃ lower than today.This Pleistocence ice sheet was the largest one found so far at present in the Qinghai Xizang Plateau. 
  • Liu Weidong
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    The Jianghan Plain, taking its name from the Changjiang and Hanshui Rivers. is located between 29°26’ -31°23’N and 111°30’-114°32’E. and has an area of more than 36 000 square kilometers. The Plain. in the central south of Hubei Province. forms part of the Lianghu Plain (the Middle Reach Plain of Changjiang River) and the Donting Lake Plain in Hunan Province. It has a subtropical monsoon climate, with a frost-free period of 243-275 days and a mean annual precipitation of 980-1300mm. Low and flat and crisscrossed by rivers and lakes. it is the major farming area of Hubei Province. known as" ia land of fish and rice". Since the Ming Dynasty. the plain has been one of improtant commercial productive bases of China for grains and aquatic products. In this paper, land types in the Jianghan Plain are classified through the analysis of its physical environmental charactenstics. Some new quantitative methods for the analysis of land type structure are introduced.and the scheme for comprehensive physical regionalization is worked out on the bases of land type structure and the areal differentiation in this plain. 
  • Zeng Zungu, Xiong Xiangen
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    The agricultural structure is defined as an interactive combination of controllable factors which constitutes a supporting framework of the agricultural system. It is a dynamic structure which changes with economic development. In the process of agricultural modernization changes of agricultural structure include following aspects:1. Extending industrial chain with in agricultural system and developing pre-and post productive sectors.2. Changing input structure and substituting land and labour with capital and technical investment.3. Changing management and organization structure. including changing tenure system. enlarging farm scale. improving agricultural service. developing regional and professional cooperatives and agricultural-industrial-commercial integration etc.4. Rationalizing sectoral structure and areal specialization of agricultural production.5. Developing agricuhural infrastructure and improving circulation and market system of agricultural products.Currently in China. the traditional agriculture is gradually transforming into the modern one and the changing agricultural structure attracts attention of many experts from different disciplines.The authors of this article suggest that geographers should actively take part in the studies of agricultural structural changes. and the concept of " major agricultural system" should be accepted for the purpose of expanding the area of their scientific investigation. encouraging theoretical innovation. improving reseach methods and techniques.and serving the agricultural modernization.