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  • 1997 Volume 52 Issue 5
    Published: 15 September 1997
      
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  • SOCIAL POLARISATION AND SEGREGATION PHENOMENON IN BEIJING
    Gu Chaolin, Christian Kesteloot
    1997, 52(5): 385-393. https://doi.org/10.11821/xb199705001
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    The biggest change in Beijing during the last decade was its social structure. The transition is changing the existing situation of social “equality”, and leads to polarization both in individual communities and in society as a whole. As a result, social variations and conflicting interest are growing, and some new social groups are emerging. In this paper we seek to explore a new urban phenomenon on past 1984 Beijing: social polarization and segregation. At first, we will discuss some elements explaining social polarization. The elements and the processes can be traced back to two main aspects of the economic reforms, namely the internal reforms unleashing a huge rural exodus and the open door policy. Special attention will be paid to the new lower side of the social ladder, constituted by the rural immigrants, labeled floating population. Finally we will explore how these social changes translate into urban segregation, with some consideration for future developments.
  • ON THE THREE ANCIENTS REMOVE OF LATE THE STONE AGE OF CHINA AND THE CLIMATE CHANGE
    Lu Wei, Wu Baolu
    1997, 52(5): 394-402. https://doi.org/10.11821/xb199705002
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    In this paper, we give a method to quantize the characters of a cultural relic.
  • AN ANALYSIS ON LOCATION FACTORS AFFECTING THE SPATIAL DISTRIBUTION OF SHANGHAI LAND VALUE
    Du Debin, Xu Jiangang
    1997, 52(5): 403-411. https://doi.org/10.11821/xb199705003
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    With a technique of GIS and a method of multiple linear regression analysis, the spatial distribution of Shanghai land values and its relationship with some location factors are examined in this paper. The data base of land values consists of 166 land parcels leased during 1993-1994. The land value map of constructed from 155 sample land lots shows that the spatial distribution of Shanghai land values has some distinct spatial features. First, the highest land value areas are located along Nanjin Road, Huaihai Road and Bund. From these high land value areas there is sharp decline in all directions except in two regional shopping centers, Xujiahui and Yuyuan. Secondly, there is no conspiculus perk land value intersection within the CBD, which locates within Middle Xizang Road, East Beijing Road, Bund ad East Jinling Road. Finally, the land values of Pudong are much lower than that of Puxi and there is a sharp drop along Puangpu River on the land value isogram map. The multiple regression model between Shanghai land values and selected location factors calculated from the sample land lots is as fellow:Y=734.98-21.66X1-36.34X2-27.42X3-4.61X4-1.71X5+0.18X6where Y is the land value at any location, X1 is the distance of a land lot to the center of Shanghai (Renmin Square), X2 to Nanjin Road, X3 to Huaihai Road,X4 to Bund, X5 to major outlying regional shopping centers, X6 to some major transportation nodes. Three unimportant variables, X4 , X5 and X6, being rejected, the model is simplified as:Y=732.09-28.70X1-35.16X2-25.17X3 The above two models indicate that Nanjin Road is the First important location factor affecting the spatial distribution of Shanghai land value, the city center is the second one and Huaihai Road is the third one. Bund, the regional shopping centers and the transportation nodes have little influence on the spatial distribution of Shanghai land values. The relationship between shanghai land values and the selected location factors is determined by the distribution of commercial activities, the characteristics of the CBD and the spatial form of the city. Nanjing Road and Huaihai Road, both of which stretch more than 5 kilometers, are traditional commercial ribbons and are more and more concentrated with various commercial activities especially after large scale redevelopment in recent years. In addition, there are many other commercial streets, such as Middle Xizang Road, East Beijing Road, East Jinlin Road, Middle Henan Road, in the central area of the city. The great concentration of commercial activities in the central area, especially along Nanjing Road and Huaihai Road, results in a steep rise of the land values. So Nanjing Road, the city center and Huaihai Road become the most improtant location factors affecting the distribution of Shanghai land values. Compared with the central area, the concentration of the outer areas of the city is very low. So the regional shopping centers and the transportation nodes nearly have no affection on the land values. Although Bund is an important sightseeing area and is becoming a major financial street of Shanghai it has little influence on the spatial distribution of land values of the whole city because of its location on the east side of city and adjacent to the low land value area of Pudong Bund.
  • AN ANALYTICAL STUDY ON EID AND ESA ON A SLOPE
    Sun Hanqun, Fu Baopu
    1997, 52(5): 412-420. https://doi.org/10.11821/xb199705004
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    In this paper, the authors study the existing conditions, ranges and distributional laws of the EID and ESA on a slope with an analytical method. EID (Equal Insolation Duration) means that the insloation duration on a slope is not variable according to the data. In the other words, the insolation duration on a slope is equal in every day of a year. ESA (Equal Sunshine Azimuth) is the azimuth of a slope on which EID is existing. The insolation duration of a slope is relative to the sunrise and sunset hour angles ω1, ω 2 . ω1 and ω2 are composed of the sunrise and sunset hour angies ωs1 , ωs2 on the non horizental surface and the sunrise and sunset hour angles - ω0, ω0 on the horizental surface. There are many different combined relations. For a slope with given latitude, gradient α and slope azimuth β , the combined relation can vary with the sun declination δ . When one combined relation changes into another one, there are two critical sun declinations δc . They meet the following condition: tan2δc= sin2 cos2φ/(1- sin2βcos2φ) Becaus the sun declination δ vary on the range of (-23.45°,23.45°), the following relation is necessary for δc existing: sin 2βcos 2φ≤ sin223.45°On the other hand, when sin 2β cos 2φ> sin 223.45°,we can not get the critical sun declination δc.
  • A STUDY ON THE COUPLING RELATION BETWEEN THE WATER AND SEDIMENT YIELD SUB SYSTEM AND RIVER CHANNEL DEPOSITION SUB SYSTEM: AN EXAMPLE FROM THE YELLOW RIVER
    Xu Jiongxin
    1997, 52(5): 421-429. https://doi.org/10.11821/xb199705005
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    Based on the data from the Yellow River, by applying the concept of system coupling, this paper deals with the coupling relation between the water and sediment yield sub-system in the upper and middle river basin and the sediment deposition sub system at the lower river reaches. To describe this coupling relation quantitatively, a multi regression model has been setablished to express the relation between the sedimentaton in the lower Yellow River and the water and sediment quantities from the 4 different source areas in the upper and middle river basin, based on the yearly and the flood event data, respectively. The results obtained show that, on the basis of yearly data, given other factors, each ton sediment from the coarser sediment producing area causes a sedimentation of 0.445 ton, but for each ton sediment from the fine sediment producing area, this sedimentation is only 0.154t, meaning that the effect of the former in causing sedimentation is two times higher than the latter. This indicates that the sediments from coarser and finer sediment producing areas have different influence on the sedimentation process in the lower Yellow River.
  • PALYNOLOGICAL RECORD OF PALEOVEGETATION CHANGE DURING HOLOCENE AT NORTH TUMOTE PLAIN IN INNER MONGOLIA, CHINA
    Wang Fengyu, Song Changqing, Sun Xiangjun
    1997, 52(5): 430-438. https://doi.org/10.11821/xb199705006
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    The Chasuqi profile (40°40′N, 111°08′E) is located in front of Daqingshan Mts., which is 55km westward from HOHHOT, capital of Inner Mongolia province. The landform at the front edge of pluvial fan is gentle with a grassland vegetation. The profile is 280cm deep with peat deposits at the upper part and clay or salt clay at the lower part. The 9100 aBP of bottom age and 0 aBP of the top are infered by linear interpolation based on 4 14 C control data. 50 types, 19 tree families and genera, 22 shrubs and herbs, 5 quatics and 4 ferns spores were found by analysis of 133 samples. The plentiful pollen appear and the highest total influx is up to 2765 grains/(cm 2·a). The tree pollen percentage, the highest up to 97 2%, is more than shrubs and herbs within the 58cm￣190cm depth. The highest influx of that reaches to 615 grains/(cm 2·a). On the other hand, the pollen percentage of shrubs and herbs is more than that of trees within the depths of 9 cm￣58 cm and 166 cm￣254 cm, in which the highest is up to 100%, and they are mainly consisted of Artemisia , Chenopodiaceae and Ephedra . Five pollen assemblage zones were established according to stratigraphically constrained cluster analysis. The vegetation change were infered as following: (1) from 9 100 aBP￣7 400 aBP, the steppe vegetaton dominated was inferred according to low influx and rare types; (2) from 7 400 aBP￣5 000 aBP, the tree steppe vegetation formed due to the evidence of increasing total influx, especially trees; (3) from 5 000 aBP￣4 100 aBP, the total influx reached to the highest and the percentage of tree pollen diminated obviously which reflects a forest vegetation; (4) from 4 100 aBP￣1 350 aBP, the composition of pollen types changing greatly, the vegetation underwent forest tree steppe steppe; (5) from 1 350 aBP￣0 aBP, the typical steppe vegetation was reflected by pollen asseblage mainly consisting of herb types. In conclusion, there are some similarities in vegetation changes in the profile comparing to the results from another area but the time series.
  • THE IMPACTS OF GROUND WATER ON EVAPOTRANSPIRATION BY USING LYSIMETER
    Chen Jianyao,,Wu Kai
    1997, 52(5): 439-446. https://doi.org/10.11821/xb199705007
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    A new lysimeter, built in 1991 in Yucheng Field Experimental Station of Chinese Academy of Sciences (CAS) and started operation since then, is 5 m in depth and 3.14 m 2 in area. The weight of the lysimeter is about 3.4×104 kg, and the measurement resolution is about 60 g, e.g. 0.02 mm in water depth. The ground water table inside the lysimeter can be adjusted to be the same as that in the adjacent area. The new lysimeter measures evapotranspiration and evaporation from ground water surface at the same time following the concept of water balance:P+I+Eg=Pa+ET+R±ΔSwhere P, I, Eg, Pa, ET, R, ΔS is precipitation, irrigation, evaporation from ground water, deep percolation, evapotranspiration, runoff and soil moisture variation of the whole column respectively. This paper examines firstly the representability of evapotranspiration measurement of this lysimeter, which shows that there is a good consistency between the variations of soil moisture and heat condition inside lysimeter and that outside. The variation of soil moisture storage of 0 cm -150 cm inside lysimeter ( ΔW 1 , in mm/d) is well related to that outside lysimeter ( ΔW 2 , in mm/d) with correlation coefficient of 0.93 in the form: ΔW 2 =0.77* ΔW 1 -0.0178, which indicates that ΔW 2 is roughly 77% of ΔW1 . The evapotranspiration measured by the lysimeter can represent well that of the adjacent area even though one coefficient of approximately 0 75-0 85, according to the comparison of several methods, is needed in order to get real evapotranspiration of that adjacent area. The figure of scatter points of measured Eg and ET show that their relationship is not either simple linear or non linear, and both of them may exist. The average ratio of E g to ET during the period of Dec. 11,1995 to May 30,1996 is about 17.1%, when winter wheat grew and the ground water table was between 1.89 m and 2.65 m. The empirical relationship of the average ratio PRE under one certain water table and this water table has been obtained with the coefficient of about 80%:PRE=-0.559*D+1.358where D is ground water table in m. PRE is about 30% when D =1.89 m, and 17.1% when D =2.12 m according to the above relationship.
  • EVAPOTRANSPIRATION, SOIL EVAPORATION AND WATER EFFICIET USE
    Wang Huixiao, Liu Changming
    1997, 52(5): 447-454. https://doi.org/10.11821/xb199705008
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    Agricultural water use, i.e. field evapotranspiration includes crop transpiration and soil evaporation. Studies on field evapotranspiration, ratio of transpiration and soil evaporation, and agronomic measures for controlling soil evaporation are the important aspects of the researches on field water efficient use. During the period of 1984 to 1996, several field experiments have been carried out at Luancheng Agricultural Ecosystem Station to measure water balance components, crop physiological parameters. Based on the experimental research and model simulation, the water conditions for crop growth, relationship between evapotranspiration and soil evaporation, effects of mulching on soil evaporation, and effects of irrigation on crop growth were analyzed in this paper, which would provide the scientific basis for efficient water use. From the experiments, it was known that soil evaporation accounted for 29.0% of the field evapotranspiration during wheat growth season, which showed the potential for reducing soil evaporation. It was clear that mulching could effectively control the soil evaporation. Wheat stubble could prevent soil evaporation in corn field by 34.7%, and the mulching with crop straw could reduce soil evaporation by 50%. The time and rate of irrigation affect the availability of irrigation water. The simulation results of WAVES showed that there was no agricultural production without irrigation in the dry year in this region, while developing dryland agriculture would be practical when several succesive wet years happened.
  • ON THE WATER CONSUMPTION CHARACTERISTICS OF WINTER WHEAT AND WATER SAVING IN AGRICULTURE
    Wu Kai, Chen Jianyao, Xie Xianqun
    1997, 52(5): 455-460. https://doi.org/10.11821/xb199705009
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    The total output of winter wheat in Huang Huai Hai Plain in 1993 accounted for 44.4 per cent of that of the whole state and 47.2 per cent of total grain crop of this region. Therefore, it is important to stady the water consumption characteristics of winter wheat. According to the experimental data measured by the lysimeters in Yucheng Experimental Station, CAS, the average water consumption is 482.5 mm for winter wheat and 854.8 mm for both winter wheat and summer maize, for which the rainfall can provide 30.7 per cent and 65.3 per cent respectively in Yucheng Region. Two obvious peaks and three key water demand periods exist in the whole water consumption process of winter wheat and it is possible to make full use of these periods for the irrigation, e.g., the winter, the jointing, the heading or the milking period. The measuremants by the lysimeters, the Bowen ratio meter, the evaporation pans and other pieces of equipment indicate the existence of linear relationships between the daily water consumption of winter wheat and the environmental factors, such as net radiation, soil heat flux, the infrared temperature, the evaporation from water surface and the growing period in days after planting. Two good relationships have been found, one between the cumulated daily water consumption of winter wheat and the growing period in days after planting, and the other between the daily water consumption and net radiation, the infrared temperature of crop canopy and the evaporation from water surface. The above results may be used to estimate the regional crop water consumption and the regional irrigation forecast for the area with similar natural conditions.
  • STUDIES ON THE CONTROL OF SOIL WATER PROFILE AND ROOT DISTRIBUTION
    Feng Guanglong, Liu Changming
    1997, 52(5): 461-469. https://doi.org/10.11821/xb199705010
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    There are feedback interrelationships between shoot and root, namely shoot growth and development could be controlled by root growth and distribution which can be also adjusted by soil moisture distribution in soil profile. In order to determine an optimum irrigation method for controlling water distribution with depths which could adjust effectively root growth and distribution in soil profile, the field experiment with four treatments of irrigation application depth and frequency (once irrigation, the same amount of water was irrigated by 1,2 and 3 times, respectively) were conducted from 1995-1996 at Luancheng Experimental Station of Agricultural Ecosystems, Chinese Academy of Sciences, which located in the North China Plain. Under different irrigation conditions, shoot growth, grain yield, root growth and distribution, soil water extraction patterns, consumptive water use, and water use efficiency (WUE) were investigated in detail. The more soil water content, the higher the rooting density, the density was reduced by decreased soil moisture content. Root length density was much more in the deeper layer due to soil water stress on the top of layer, meanwhile, more amount of soil water was depleted. Soil water extraction patterns were correlated to rooting distributions. Under frequent, light irrigation treatment (I3), soil moisture content and extraction efficiency were higher at 0 cm-30 cm layer in which 61% total root length density was observed, 74% total amount of water was consumed from the layer, the proportion of soil evaporation to evapotranspiration was 28% which was only 4% greater than the conventional irrigation (I1). Grain yield and WUE were improved separately by 17% and 11% in comparison with I1 treatment. Under I1 and rainfed treatment (CK), 37% and 30% total amount of root distributed in 50 cm-100 cm depth of soil from which 22% and 29% total amount of water were extracted, respectively. The crop achieved its maximum LAI and dry matter of stem and leaf at flowering stage, the rate of root elongation is the highest over growing season in the period (0.2 cm/cm 3穌-0.25 cm/cm 3穌). Average the maximum evapotranspiration rate (5.5 mm/d, 4.6 mm/d) and transpiration rate (4.6 mm/d, 3.3 mm/d) of all irrigation treatments occurred in flowering and filling stages. Otherwise, the average rate of soil evaporation is 1.3 mm/d during jointing stage which is the highest rate from jointing to maturing.
  • CLIMATE INSTABILITY RECORDED IN ICE CORES AN OVERVIEW OF RECENT FINDINGS BY ICE-CORE STUDIES
    Qin Dahe,,Li Peiji
    1997, 52(5): 470-476. https://doi.org/10.11821/xb199705011
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    Analyses of ice cores drilled through Greenland and Antarcitica ice sheets and high glaciers have produced remarkable advances in our understanding of the evolution of Earths climate. The past a few years have seen a revolution in our thinking on climate variability and tropic climate sensitivity, because of the signs of fast climate oscillations and cooling ice age tropics displeayed in the ice cores. One of the principal progress made by GRIP and GISP2 ice cores has been the demonstration that the last glacial period was punctuated by a series of abrupt warm interstadials during which temperature increased by about 5℃-8℃ for a few hundred years. Another sigificant new finding has been the document that the Eemian interglacial was interrupted by a series of severe cold periods, which began extremely rapidly and lasted from decades to centuries. Thirdly, a high glacier ice core opens a view of the ice age tropics. Two ice cores from Andes found that the tropics did share in the cooling as much as 8℃ to 12℃ lower than today during the late glacial stage. And the last, analysis of borehole temperature at GISP2 reveals that polar amplification of climate change is a central characteristic of Earths climate. With these new discoveries, the widely accepted concepts of a noisy glacial climate and a quiet interglacial climate as well as thermostat tropics came under challenge. And they result in the questions about the consequences of future global warming. Will the greenhouse effect end the recent climate stability and bring rapid climate change to our doorstep?