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  • 1987 Volume 7 Issue 3
    Published: 20 May 1987
      

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  • Chen Hailong
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    According to historical records,there are 264 drought and flood years, occurred in the upper and middle reaches of the Changjiang River during last 1020 years from 961 to 1980.The evolutionary law and developing trend of drought and flood years are studied.The distribution of drought and flood years are non-uniform and the dry and flood seasons in a year are concentrated.At the angle of monsoon circulation,at present the climate in the upper and middle reaches of the Changjiang River is just in the late stage of frequent drought period and the early stage of least flood period.In addition,the cycle of drought and flood and the feature of drought and flood occurred in the upper,middle and lower reaches of the Changjiang River are analyzed.It shows that the short period less than 10 years is in the majority,and the drought and flood occrred most frequently in the middle and lower reaches of the Changjiang River.
  • Luo Manjia
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    On the basis of"The Statistical Data of Guangdong Province in 1981", and selected 14 original variables,107 counties and suburbs in Guangdong Province of China are classified.In the classification,cluster analysis is applied,and the cluster hierarchy of the agro-ecosystem is achieved with a computer. One of the characteristics of agro-ecosystem is obvious regionalism.Therefore,it is necessary to research its regional structure in the study of macrosystem.According to the output level,the plant structure and the input level of energy,there is an evident regionalism in the agro-ecosystem of Guangdong Province,which presents approximately concentric circles where centre is Guangzhou city.
  • Wang Miaohua
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    "The Investigation on the Panjiang River" is a geographic thesis written by Xu Xiake,on the basis of his on-the-spot investigation,with the purpose of correcting the mistakes in"History of Great Ming Unity" and clarifying the sources and courses of the North Panjing River and the South Panjiang River.Most of the conclusions are right,but there are obvious mistakes owing to the limitation of the times.In addition,there are still some questionable points.For example:1)The exposition about the sources and courses of the North Panjiang River and the South Panjiang River quoted from"Hitory of Great Ming Unity"can not be found in any one of the four editions of"History of Great Ming Unity".2)"History of Great Ming Unity" says that the North Panjiang River and the South Panjiang River join at Pingfaheng Shanzhai. The diary on 24 Sept.1637 in "Xu Xiake’s Travels Travels in West Guangdong.Three" criticized this view seriously.But it can not be known why this criticism is not present in"The Investigation on the Panjiang River". The possible explainations about it are as follows:1)Xu Xiake mistook the mileage of the Bomeng and Duiyong mountains for that of the North Panjiang River and the south Panijaug River.2)There are something to be left out seriously in"The Investigation on the Panjiang River" 3)The diary on 24 Sept.1637 annotated by others instead of Xu Xiake himself.Spreading it from place to pa place,the writer’s name disappeared.Or the writer did not sign at the very beginning.4)The diary on 24 Sept.1637 was written by Xu Xiake himself,while "The Investigation on the Panjiang River" was writtern by somebody else in Xu’s name.
  • Chen Xiqing
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    At present there exist two ecologically different types of sub-alpine dark conifer forests in China and Japan,which are mainly composed of Picea, Abies etc.Most of Abies and Picea species belong to typical cold-temperate type.The summer temperature at the lower limit of these trees in different latitudes can be derived by the regression equation:Y=0.12X+10.01 The warm-temperate type of dark conifet forest is composed of only few species such as Abies beshanzuensis.There also developed the equivalents of these two types of dark conifer forests during the late glacial period(30000-22000 B.P.).Their southern boundaries in east low-lying plains are defined as 37°N and 30°N,respectively.The summer temperature in the early glacial period dropped 9.4-9.8℃ in east plains and 7.0℃ in west plateaus.That testified the existence of"cold-trough" in the glacial period in east China.The cold-wet climate in the early glacial period reflects a unique climate regime during the transitional period from interglacial to full glacial. The flourish of dark conifer forests is a vegetation response to the climate.
  • Jiao Yaning, Wei Chengkai, Fu Wenxa
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    The loess accumulated in the Liaodong Peninsula is a special type of loess in China.On the basis of the distribution,stratum sections and material composition of the loess in the peninsula,the material sources and formation mechanism of the loess are discussed.Acerding to the data of 14C dating and thermoluminescence,the age and the sedimentary rates of the loess are obtained.The loess in the peninsula is closely relative with the loess in Chifeng of the Neimonggol Autonomous Region.They both are silt accumulation transported by wind from inland deserts in the same period of the Pleistocene.Bat owing to the influence of special climate conditions,some loess, by the surface water,oecured a series of changes.The study on the loess in the peninsula makes it possible to further understand the palaeogeography and palaeoclimaete in the Pleistocene in the Liaodong Peninsula.
  • Zhao Huanchen
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    Through the principal component analysis of two climatic elementssunshine and relative humidity,the dominant distribution patterns both of perennial sunshine duration deviation(3)and perennial relative humidity(Fig. 3)in the northeast region were defined.The author used the results derived from the principal component analysis of perennial monthly mean atmospheric pressure(Fig.1)to explain the cause and process forming dominant distribution patterns of perennial sunshine deviation(Fig.2)and relative humidity deviation(Fig.4),and approach the regional characteristics of two climatic elements with time change.The similarity(distance Fig.5)among the clusters was obtained with the group average method and based on the time changing eigenvalues(factor loading)of principal components of sunshine and relative humidity correlated respectively with sunshine and relative humidity in observation stations and points.The author took the similarity as the comprehensive indexes for regionalization to map the regionalization of time changing characteristics of sunshine(Pig.6)and the regionalization of time changing characteristics of relative humidity(Fig.7)in the northeast region.Finally,the author pointed out that using the cluster analysis method of principal components to regionaliza the climatic elements was a new method for regionalization.therefore,it is of great significance in the research on regional climatic characteristics,especially on regionalization or classification theory,and in the practical application of qualitative system combined with quantitative system.
  • Zhou Chenghu, Tang Qicheng
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    This paper discusses the application of goal program to the identifacation of parameters of a hydrological model.The clue and calculating steps are discribed in detail.Through comparing the results from the minimum square method with the results from the goal program method,it is credible that the goal program method is a new and better one to identify the parameters of a hydrological model.
  • Wei Shengmin
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    The paper analyses the water budget(precipitation and evaporation)of the arid plateau in north of the Weihe River in Shaanxi Proyince.The precipitation data are collected from each station in this region for 49 years, and from Xian station from 1932 to 1980.The precipitation for different guarantee is obtained.The evaporation from water surface and the potential evaporation of the region are calculated by H.L.Penman’s formala. The annual actural evaporation of the region is calculated by H.P.Bailey’s formala.The concept of optimal evaporation is introduced and the surplusdefieit index of water is disueussed.The potential evaporation ealculatied by Penman’s formala being emended,the surplus-deficit amount of water is obtained. The principal conclusions are as follows.1)The annual precipitation is 525.97-641.1mm.It is increascent from east to west.80% of ensuring rate of precipitation is 470-568mm.2)The annual evapotation from water Surface and the potential evaporation are 920.1-1303.9mm and 748.0-1101.9 mm,respectively.They are decrescent from east to west.The maximum of annual variation occurs in June,and the minimum in December.The difference of annual actual evaporation is not large,471.6-516.8mm.The annual evaporation ratio is 0.79-0.92.It is also decrescent from east to west.3) The annual deficit-surplus amount of water is-215.1-15.0 mm.Water is surplus in autumn and deficit in the other seasons.
  • Sun Guangyou, Zhang Wenfen
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    The old channel of the Huanghe River is located to south of Maqu,Gansu, Province,72.5Km long from south to north,5-11Km wide from east to west. A vast piece of swamps developing within the old channel,presents an inverse"S"shape clearly on Landsat images.As for geomorphological type,it corresponds to the second terrace of the modern Huanghe River.The surface constituents are peat layers and fine sand with river facies,The mineral composition is similar to that of the second terrace of the modern Huanghe River near Maqu. Neotectonic movement is a basic cause of the old channel formation. Tangke was the sunsidenee center of the Ruoergai Plateau in the Pleistocene,which caused the old Huanghe River to move eastward.The capture of the Huanghe River by the Baihe River is a direct cause.The old channel developed in the middle Pleistocene.Based on the analysis of geomorphology and stratigraphy,in the Pleistocene the old Huanghe River wriggled on the Ruoergai plateau extensively.Riganqiao-Keharqiao compond valley near Waqen is a large old channel of the Huanghe River.In these old channels there are rich peat resources.
  • Qi Shaohua
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    The Songhua River is an important economic river in the Northeast China From the Songhua River basin,95 unpolluted water samples,53 suspended substance samples,100 fish samples and 144 sediment samples are collected.The test of the distribution types of the mercury in the water body show that the mercury in water,suspended substances,fish,and sediments presents mostly normal and logarithmic normal distributions.The background values of the mercury in the water body of the basin are 0.009-0.025ppb in water,0.651-2.757ppm in suspended substances.0.050-0.254ppm in fish,0.016-0.070ppm in silt sediments,and 0.08-0,023ppm in sandy sediments,respectively,
  • He Shichun
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    Fluorine is distributed in natural water regularly,by way of zonal or nonzonal distribution.The zonal distribution of fluorine is closely related with weather,topography,landforms,the acid and alkali nature of soils and the temperature of natural water.The nonzonal distribution is mainly related with warm springs,underground hot water,vocannos and the regions associated with deposit containing fluorine. In nature,the rocks containing fluorine are dissolved in water by water disivation.The fluorine contents in natural water is quite different.Under humid climatic conditions,underground water contains a small amount of fluorine.In saline alkli regions under dry climatic conditions,shallow ground water contains a large amount of fluorine.The water in rivers contains a small amount of fluorine.The fluorine contents in lakes are quite different. The fluorine content in sea water is stable.Warm springs and underground hot water contain a large amount of fluorine,so they can not be drunk. The amount of fluorine in natural water is proportional to Na+1,Cl-1, SO4-2 and mineralized degree.Even in a same place,ground water contains a small amount of fluorine in water-bearing strata with coarse particles,and a large amount in strata with fine particles.In saline alkali regions,the water in deep wells contains a small amount of fluorine.Sometimes the water containing a small amount of fluorine can be found on certain sections of river banks.This kind of water can be used as sources water.This paper points out the way to look for the water containing a small amount of fluorine.