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    Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
  • Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    WANG Hao, JIA Yang-wen, WANG Jian-hua, QIN Da-yong, ZHOU Zu-hao, QIU Ya-qin, YAN Deng-hua
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    The paper applies the dualistic distributed hydrological model (WEP-L model) to stu-dy the evolutionary laws of the Yellow River Basin's water resources under the impact of human activities.The water resources assessment results under present underlying surfaces are compared with those under historical underlying surfaces,and the water resources assessment results under no water use condition are compared with those under water use condition as well. By contrast,it is shown that the quantity and compositions of water resources changed distinctly under the impact of intensive human activities.The two main variations are as follow:(1)the surface water resources reduced but the ground water resources which is unrepeatable with the surface water resources increased;(2)the special water resources reduced but the general water resources increased accompanied with increase of the effective evaporation,namely,effective utilization of precipitation.The research achievement can be referenced for comprehensive management and the water safety strategic planning of the Yellow River Basin.
  • Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    CHE Yue, YANG Kai, FAN Qun-jie, ZHANG Yong
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    The upstream of Huangpu River is the main headwater area in Shanghai.Although the protection program of the upstream has been identified recently,the water quality in the source areas did not change better.Based on the monitoring data of the upstream water quality in 1986-2002 and the boundary water quality in 2002,the water quality variance in the intake and upper reaches was discussed.The spatial variations of pollutants were analyzed, and there was significant difference between the water quality of intake and those of upper reaches.The concentrations of the pollutants were also affected by the periodic evolvement.The main factors controlling water environmental quality (regional development and water quality of upper reaches,urbanization and population scale, local economic level and point pollution,land use patterns and non-point pollution)were analyzed.Finally a scheme of source water area protection in the upstream of Huangpu River was established.The water-quality management and landuse planning should be integrated in the upper Huangpu River watershed.The source water area protection program should give priority for financial assistance to high-value,low-environmental-impact activities.The infrastructure improvements and financial assistance should be provided by source water area protection program.Watershed management for water supply in Shanghai,a developing world city should be developed.
  • Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    YAN Jin-feng, CHEN Xi, LUO Ge-ping, XU Wen-qiang
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    Taking an oasis of Sangong River watershed,located on the northern slope of Tianshan Mountains of Xinjiang as a case,we studied the impacts of land use/cover change(LUCC)on shallow groundwater level and quality in the oasis of arid area,by employing the Geographical Information System (GIS),Remote Sensing (RS) and Geostatistics.Land use/cover was classified mainly into 9 types of irrigated lands,cities,towns,thorps and industrial and mining lands,shrubby lands,desert grasslands,saline or alkaline lands,swamps,reservoirs and ponds,which were extracted from aerial images in 1978,Landsat TM image in 1987 and Landsat ETM image in 1998 by visual interpretation,and groundwater data was obtained from 20 monitoring wells spreading over the entire oasis.The result of research showed that the shallow groundwater level and quality reflected remarkable spatio-temporal changes-in alluvial-diluvial fans descended at avg 45cm per annum in past twenty-five years,the whole trend of water table in phreatic overflowing zones went into a rapid descent,especially in the 1990's,the maximal degree of decent reached 10m.The water table of irrigated land in the under part of the alluvial plain ascended at avg 7cm per annum.The groundwater quality of oasis became more and more deteriorative with an increase in mineralization during 1987 to 1998.The isogram of mineralization in oasis transformed from 200~600mg/l in 1987 to 300~1 500mg/l in 1998,and the degree of increase in mineralization reached 100%~200% at the downstream of the oasis.Anion transited from HCO3- to SO42- and CI-,and cation had a transition of Na+,K+,Mg2+ to Ca2+ in groundwater quality in south-north direction.All of these had close relations with exploitation of land resources,irrigation and drainage,surface evaporation and use of chemical fertilization.In a word,the change of land use/cover by human factor played decisive role in spatio-temporal changes in groundwater table and quality of the oasis in arid area.The sustaining increase in non-agriculture lands of cities and thorps and irrigated agriculture lands caused a remarkable descent in water table at upstream of the oasis,and produced a great effect on groundwater quality at the stream down of the oasis.
  • Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    MO Xing-guo, XUE Ling, LIN Zhong-ghui
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    With the aid of Geographic Information System,a Soil-Vegetation-Atmosphere Transfer model (VIP model)was used to simulate crop evapotranspiration in the North China Plain(NCP) from 1981 to 2001 based on GIS,RS and meteorology information.The simulated evapotrans-piration is comparable with the observation of Lysimeter and data from the literature.The results show that cumulative evapotranspiration of winter wheat is higher in the southern part than that in the northern part of the NCP,about 200~400 mm in the northern and 400~466 mm in the southern.For summer corn,the cumulative evapotranspiration is 230~380 mm in the northern part and 380~470 mm in the southern.During most of the years of the simulated period,precipitation amount was less than actual evapotranspiration of winter wheat,whereas the situation is quite different for summer corn in the NCP.
  • Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    FENG Zhi-ming, YANG Yan-zhao, LIU Bao-qin
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    Researches on the field water balance in Gansu province have been carried out with an accurate soil-water balance model,taking land use and the precipitation into account along with comparisons of water demand and deficits of different crops.Results show that water demand for all crops on the farmland is 121.06 billion m3,the corresponding water deficit is 43.28 billion m3,and the surplus water is 0.62 billion m3.Precipitation can not meet water demand of the crops and is the main characteristic in Gansu province.For most crops,water deficit appears in summer, and the quantity reaches 60.20% of the total deficits.The Cv value of cotton is the smallest among the ten summer crops,and that of hemp is the greatest.The water deficit increases progressively from southeast to northwest,and the surplus water decreases progressively from southeast to northwest.Water satisfactory rate and Cv value of surplus and deficit show a decrea-sing trend from southeast to northeast.
  • Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    LI Yun-ling, PEI Yuan-sheng, QIN Da-yong
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    The river courses in the lower Heihe River are all natural ones with irregular cross sections and great seepage,belonging to broad-shallow type of sandy riverbed.The channel seepage is of great significance to ecosystems in the lower reaches which supply groundwater to sustain natural vegetation.However the seepage situation of river courses in the lower Heihe River has not been monitored and investigated for a long time.The usual percolation coefficient method thus cannot be used for calculation.At present, the amount of seepage is mostly estimated with relatively simple ways.Based on the relationship between sections and discharge,the seepage laws are analyzed according to the need of water resources real-time regulation and long series allocation.Meanwhile channel seepage laws considering the short term effects of water regime and average seepage laws of long series water resources allocation are achieved.
  • Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    SUN Xian, LIN Zhen-shan, SUN Yan
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    The total farmland resource is decreasing at a rather greater speed in recent years in China.The major reasons include:construction land use,ecologic defarming,agricultural struc- ture adjustment,catastrophic failure and so on,which will badly affect the safety of food supplies in our country.To solve the problem of national food security caused by cropland reduction,we advance several dynamic equations on arable land change according to current situation.By the 95% self-sufficiency goal of foodstuff brought forward by the white book Food Issue in China,the insurance quantity of cultivated land should be 1.216 6×108hm2.In our model,we present several recommendations and projects for protecting farmland correspondingly based on numerical simulation,and make a cultivated land output prediction from 2004 to 2010.The result of the study shows:(1) only depending on supplement from reserved cultivated land is not enough to ensure food safety by the yearly decrease rate of farmland at present; and (2) returning arable land to forest and grass plays an important role in the general decrease of cultivated land and their mutual coordination is the key problem to ensure national food security.So we should try our best to reduce farmland occupation for construction purpose,make reasonable ecologic defarming planning,encourage precision farming to increase per unit area productivity and adjust people's dietary structure to reduce meat consumption.
  • Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    WEI Su-qiong, CHEN Jian-fei
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    Comparative study of LUCC between Fujian and Taiwan could be a good case for the stu-dy because of their geographical proximity and their historical and cultural similarity.Fujian and Taiwan have gone through and are in different economic development phases.Now,Taiwan is in the stage of post-industrialization and Fujian is in the middle stage of industrialization.By using the official statistics,quantitative changes of cultivated land in Fujian and Taiwan were analyzed. The results showed that these two provinces seemed to have the same characteristics of cultiva-ted land changes,i.e.,increase at first then followed by decrease, and the general tendency was decrease.However,the phase of increase at first then followed by decrease in Taiwan happened somewhat later in the whole process,if compared with Fujian.Additionally,the speed of the cultivated land's decrease was slower in Taiwan.Based on calculating of the yield per ha in all the cities and counties in Fujian and Taiwan,the quality changes of cultivated land were analyzed.The results revealed that quality of occupied cultivated land was better than reclaimed cultivated land in Fujian,but Taiwan was opposite to Fujian,which was effected by the Farmland Re-planning Policy in Taiwan.The agricultural acreage of Fujian in 2010 was forecasted by Multi Linear Regression method,its changing trend in Fujian was deducted based on a comparative analysis between Fujian and Taiwan.In order to realize sustainable use of cultivated land in Fujian province,it is rather important to raise specific productivity of cultivated land by increasing investment both in capital and in agricultural technique,in addition to strict management regulations for land use.
  • Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    YU Shu-tong, HUANG Xian-jin
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    A material metabolism analysis is a means of quantifying the burden of environment. Analysis of material metabolism can provide important information about energy efficiency, material cycling,waste management,et al in the chosen region. Given that, the paper studies the overall flows of food,energy,water,material and wastes into and out of the Greater Nangtong Area quantificationally.The most noticeable feature of material metabolism in the Greater Nangtong Area of 1996 and 2002 shows that outputs of solid wastes have generally increased at higher rates than inputs of solid material.The outputs of wastewater have generally increased at lower rates than inputs of fresh water.The speed of metabolism is higher and higher.In 2002,the consumption of material except food (material metabolism,63.34Mt/a) is as 15.8 times as that of food (human metabolism,4.01Mt/a).The consumption of energy in the form of fossil fuel and electricity(energy metabolism,1.93×1014kJ)is as much as 0.48% of all the solar energy(4.0×1016kJ)in the research region,as 17.9 times as that human body needed(body energy metabolism),and as 48.36 times as that fixated by photosynthesis.The trends of material metabolism in the Greater Nangtong Area are escalating,although all kinds of materials and energy have been used more efficiently,and recycling used rates of part of the material and energy are rising,the ecological press on land,waters and atmospheric environment has not been reduced.Finally,the paper puts forward some suggestions (such as establishing a material flow management system)on how to lower down the fragibility of regional metabolism and increase its efficiency in Nantong city.
  • Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    ZHANG Yao-guang, WANG Guo-li, ZHAO bo, WANG Sheng-yun, SONG Xin-ru
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    Twelve island counties of China are located scatteredly in four large seas including Huanghai.There exist some differences in economic level among twelve island counties because of their positions of sea area,the degree of abundance of resources of marine and land-islands, market mechanism and humanity states,island resources development dynamics and the effect of the position of their respective administrative divisions.From Gi-Ni coefficient based on per capita GDP of island counties and Lorenz curve,it also can be seen the differences are becoming smaller apparently.Seen from the industrial structure of island counties,there are different progressive course among them.According to characteristic value and distribution of island counties on the system of coordinates,we can identify different progressive stages of industrial structure and types of industrial structure.Island economy of China today is still resources-oriented economy,but in the aspect of resources exploitation and utilization,we have gradually changed the situation from merely taking utilization of marine organisms resources in domination to laying equal stress on the utilization of marine spatial resources,marine non-organisms resources,island-land land resources and marine organisms resources.Some industries which were developed on the land are starting to be shifted and extended so that the proportions of secondary and tertiary industries increased in the economic structure of island counties to a certain extent.
  • Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    QU Fu-tian, CHEN Jiang-long, CHEN Wen
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    Harmonizing the contradiction between economic growth and cultivated land conser-vation has important effect on the realization of sustainable development in China,and land conversion is the focus of that contradiction.In order to control land conversion rationally,we must understand the driving factors.In this paper we construct a theoretical framework of land conversion economic driving mechanism,and make an empirical analysis using the data of provincial level between 1995 and 2001.Results indicate that population increase and fixed assets investments are the major driving factors,land use comparative benefit and cultivated land endowment are the basic driving factors,land conversion income and the anti-governance behavior of local government has a positive relationship with the quantity of land conversion,but the development of land market and the comparative benefit of farmland has a negative relation-ship with the quantity of land conversion.As a result,some valuable propositions are presented.
  • Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    BU Wei-na, FANG Chuang-lin
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    The Yellow River Delta is developed from the exploitation of the oil resources. Altho-ugh it is in an advantageous position,it is still economically at the bottom surrounded by the developed regions.Dual structure is an important restricting factor in the process of sustainable development in the delta,including the relationship between cities and rural areas and the dissociated connection between the oil fields and districts.There are several significant opportunities to the comprehensive development,such as general reorganization and strypped-down in petroleum industry,the new tide of industry shift,the preponderant international and domestic conditions,layouts of some momentous items,improvement of transformation system,etc.To remain sustainable development, it is crucial of changeover in concepts from "building-up the city by oil resources" to "flourishing the city with harbor economy".Secondly,it is urgent to develop the downstream processing industry of oil resources and manufacturing with competitive advan-tages.Thirdly,it is necessary to put eco-agriculture into practice.And then,it is required to imp-lement congregating model in city exploitation.
  • Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    ZHAN Che-sheng, XIA Jun, FENG Hua-li, LIU Su-xia, LIU Lei
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    The paper includes assessment of ecological and socio-economic water requirements and measures of water resources allocation.Firstly,the conception framework and targets of Integ-rated Ecosystem Assessment of Western China (MAWEC),which is a sub-global assessment project of Millennium Ecosystem Assessment (MA),have been proposed. In the case study of the Sangong River Basin,changes and the corresponding driving forces of aquatic ecosystem services function have been investigated.The results showed that human activities, especially land use change, had great impacts on the ecosystem,while the ecological impacts of natural forces were quite uncertain.Secondly,ecological water demand of river corridor and off-stream ecosystem have been carried out as following:(1) eco-hydrological zoning in the Sangong River Basin;(2) defining the key region of ecological water demand on the basis of characters of natural and man-made ecosystems in the oasis region;and (3) setting the favorite ecological protect-ion objects according to annual ecological services function assessment and maximum principle of total service function from natural and manmade ecosystems.The results showed that the ecological station of 1987 was the most favorite one for ecological protection and,total ecological water demand of the protection object accounted for 24% of surface water resources in the region,where the ratio between river corridor and off-stream ecological water demand was 2.5:1.Thirdly,socio-economic water demand was projected.Finally,according to changes of resident welfare,countermeasures of water resources allocation has been proposed taking into account water bal-ance between river corridor and off-stream,water balance among socio-economic system,water balance between ecosystem and socio-economic system.
  • Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    MU Chang-cheng, SONG Hong-wen, SU Ping, WAN Shu-cheng, SUN Zhi-hu
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    The distribution patterns of plant biodiversity were studied in the two kinds of ecoto-nes between forests and swamps in the Changbai Mountains,by using transect and Shannon-Wiener index methods,in order to reveal the distribution patterns of plant biodiversity along the moistened environmental gradients or among vertical layers of communities in the Alnus hirsuta,Betula platyphylla-swamp ecotone or Betula platyphylla-swamp econtone disturbed by human activities.The results showed that:① The horizontal distribution patterns of plant biodiversity ap-pears a protruding shape along the A.hirsuta,B.platyphylla-swamp ecotones.Plant biodiversity of this kind of ecotone community is 2~3 times that of nearly swamp community, and 1.5 times that of forest community.On the contrary,it presents a concave shape,and plant biodiversity is only 80% that of nearly swamp or forest community in the B.platyphylla-swamp ecotones disturbed by human activities.②The vertical distribution pattern of plant diversity presents a "pyramid shape"in A.hirsuta,B.platyphylla-swamp ecotones,the ratio of which is tree layer:shrub layer:herbage layer being 1:3:5.In contrast,no"pyramid shape"occurs in B.platyphylla-swamp ecotones disturbed by human activities,the ratio of which is tree layer:shrub layer:herbage layer being 1:0.4:5.So human induced disturbanc has great influence on distribution patterns of plant diversity in the B.platyphylla-swamp ecotones.
  • Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    WEN Guo-sheng, WANG Lin-he, YOSHIKAWA Ken
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    To examine the changes of groundwater level in Sabina vulgaris community in Mu Us Sandy Land,automatic-groundwater-level-meter was located on the low land of S.vulgaris patches and groundwater level was recorded continuously in a year.The results were shown as follows:(1) the whole year was divided into three phases of slow rising phase (A),fast changing phase (B) and slow changing phase (C) according to the changes of groundwater level;(2) groundwater level was the highest at dawn,going down during the day time,reaching the lowest in the evening,rising at night in the fast changing phase;and (3) the critical daily mean air tempe-rature that fast changes of groundwater level started and stopped was 10.8℃.According to this,it is possible to predict the start and the stop of physiological activities of S.vulgaris,and guide planting of S.vulgaris.Relations between groundwater level and air temperature,precipitation and changes of S.vulgaris patches were discussed.
  • Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    PENG Wen-ying, ZHANG Ke-li, CHEN Yao, YANG Qin-ke
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    Soil and water loss is very serious in the Loess Plateau.Converting farmland to forest or grassland is key to control soil erosion.The samples were collected at the Ansai county of Shaanxi province in China,and according to survey of the abandoned land for restoring different plant species with different restoration time,soil samples from depth intervals of 0~20cm were collected for laboratory assessment to analyzing their soil physiochemical properties.The effects of farmland conversion to forest or grassland on soil quality in the loess hilly field were studied.The results showed that soil quality significantly improved after conversion of farmland to forest or grassland.When compared to sloping farmland,vegetation restoration has resulted in significant reduction in soil bulk density and pH,and increases in soil porosity,optimum soil moisture,soil organic matter,soil carbon,nitrogen,and available soil nutrients to differing degrees.Robinia pseudoacacia has contributed most to soil quality restoration,caragana korshinskii kom comes the second,and wasteland the least.In the same time,with the increase of abandoned time,soil texture was increasingly improved,and soil organic matter, carbon,nitrogen,and available soil nutrients occurred an increasing trend.Meanwhile,the available soil nutrients increased much more than the soil elements.Thus,returning farmland to forest or grassland can not only effectively control soil erosion,but also significantly restore soil quality.
  • Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    JIANG Ming, LÜ Xian-guo, XU Lin-shu, YANG Qing
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    Wetland has many functions and attributes,such as mitigating flood,regulating climate, preventing erosion,providing latent soil nutrient and species habitat and so on.Wetland benefits comprise functions,purposes and attribute,they can be calculated by direct value,indirect value and non-use value of wetland ecosystem.Based on GIS and evaluation means of environmental economy,estimation has been done on latent soil nutrient benefit of Melmeg Nature Reserve,at the same time,its spatial variation has been studied.The results showed latent nutrient benefit of Melmeg Reserve was 153×108 yuan,and the latent soil nutrient benefit of unit area was 10.6×104 yuan·hm-2.Results of benefit subarea indicated the latent nutrient benefit was 12.2×104yuan· hm-2 in the east of Melmeg Reserve Wetlands,12.7×104 yuan· hm-2 in the middle and 7.6×104 yuan·hm-2 in the west.Contribution rate of the organic matter and kalium upon latent soil benefit was the biggest,and total phosphorus'was the least.Estimation on latent soil nutrient benefit makes up the weakness of wetland benefit assessment.The analysis of spatial distribution of benefit will provide theoretical basis for restoration and reconstruction of wetland.
  • Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    MIN Qing-wen, LI Yun, CHENG Sheng-kui, LIU Shou-dong, YU Wei-dong
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    Urbanization is a typical feature of socio-economic development.According to the sta-tistics,from 1980 to 2001,China's urbanization level rose from 17.92% to 37.66%.Urbanization has many positive effects such as organizing mass production,improving the progress of sci-technology and education,enhancing people's living standard and so on.However,some negative effects of urbanization have been emerging especially its ecological and environmental effects. Along with the process of urbanization,lots of people migrate from countryside to city.The increase of urban residents and the change of living style increase the consumption of natural resources and natural ecosystems.So,the quantitative analysis of urban residents' living consum-ption and its appropriation to natural ecosystems can demonstrate the influences of urbanization and sustainable development in urban areas. As a new method for quantitatively measuring natural resources used by humans,ecological footprint can illustrate regional sustainable development through the analysis of energy and other resources consumption.In this paper,taking Taizhou in Jiangsu Province of East China,Shangqiu in Henan Province of Central China,Tongchuan of Shaanxi Province of Northwest China and a typical resource city,and Xilin Gol of Inner Mongolia of North China and pastoral area as examples,ecological footprints of residents'living consumption were calculated and compared. The results show that (1) about 90% of ecological footprints in Taizhou,Shangqiu and Tongchuan come from the consumption of eating and wearing but below 70% in Xilin Gol where living ener-gy consumption occupies relatively high proportion;(2)for the sake of different geographical areas,residents have different consumption styles which cause different ecosystem appropriation, e.g. per capita residents living in Xilin Gol (pastoral area) occupy 0.333hm2 of grassland ecosystem which is several times that of in other cities,residents living in Taizhou (the Yangtze valley area) occupy 0.116hm2 of water ecosystem which is two or more times in other cities;and (3)compared to the bio-productive area,the ecological footprints of city residents in Shangqiu,Taizhou and Tongchuan are all more than the whole city's ecological capacity which approves that city is one of the typical kind of ecological deficit areas.Therefore,how to effectively adjust urban residents' consumption style and structure is very significant to improve sustainable development in urban areas.
  • Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    SHEN Da-jun, CUI Li-juan, JIANG Su-mei
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    Institutions are the causes of many water problems.The unreasonable institutional set-tings result in low efficiency and high transaction costs of the system,as well as many water problems.But the institutional options for the water problems could not be fully addressed by the water sectoral reform,because institutional reforms are not only controlled by the sector. This paper analyzes the water problems and put forwards counter measures in the Shiyang River basin from an institutional aspect.Based on the reviews of current water resources development and utilization, and management institution,it identifies that the problems in water resources management in the river basin are that the traditional development model resulted in severe sectoral water shortage,regional and secotral management institutions caused frequent water conflicts between upstreams and downstreams,the neglecting and forcibly occupying environmental water usage aggravated the eco-environment,the nontransparent subsidies distorted water tariff and demand,etc.Therefore,to address these problems,it should implement integrated management of water,land and forestry resources,formulate"Shiyang River Basin Management Regulations",reform current management institutions,and develop transparent subsidy and rational pricing mechanisms.The paper also suggests to expand the functions of Shiyang River Basin Management Bureau.
  • Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    JIA Yang-wen, WANG Hao, WANG Jian-hua, LUO Xiang-yu, ZHOU Zu-hao, YAN Deng-hua, QIN Da-yong
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    This study is to establish a tool for water resources assessment and analyzing the evol-utionary laws of water resources in the Yellow River Basin by developing a distributed hydrologic model applicable to large basins.On the basis of combining the merits of distributed watershed hydrologic models and land surface processes models,we developed WEP-L(Water and Energy Transfer Processes in Large River Basins) model in which "natural-artificial" dualistic water cycle system is modeled in a coupling way.In the WEP-L model,contour bands inside sub-watersheds are used as computation units and the mosaic approach is adopted to reflect the heterogeneity of land covers inside a computation unit.In this way,the model can avoid possible serious distortions of flow modeling,which may occur if coarser grid cells are used as computation units.Variable time steps from 1 hour to 1 day are adopted in the model in accordance with different time scales of various hydrologic processes,which has improved the computation efficiency and ensures rational description of hydrologic dynamics.The Yellow River Basin was subdivided into 8 485 sub-watersheds and 38 720 contour bands,45-year(1956~2000)continuous simulations were carried out for corresponding land cover conditions,and model verification was performed by comparing simulated discharges with observed monthly and daily discharges at main gauge stations.The verification shows that the newly established WEP-L model has quite high simulation accuracies,thus it is applicable to water resources assessment and evolutionary laws analysis of water resources in the Yellow River Basin.
  • Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    HAO Shi-long, LI Bi-cheng, YU Qiang
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    The research of land use change touches upon different spatio-temporal scales,the researches to different spatio-temporal scales solve different problems.The study and analysis of the spatio-temporal rule of land-use change aims to select suitable scale,especially small scale.However,small scale land-use change research is limited by hard data availability,land use data are scarce,especially in loess hilly-gully region.The Participatory Rural Appraisal (PRA) is a method by which we can acquire the basic situations of the study area through informal interviews with local residents,which are irreplaceable for studying small scale spatio-temporal land use changes.PRA along with field measurement and GIS is applied to study the land use change in village scale,taking Shanghuang village in mountainous area of southern Ningxia as an example.The research compiled land-use spatial change maps of different period,analyzed the quantity and spatial changes of land use,and reconstructed the land use history of past 25 years with GIS.The results show that the changes of farmland and forestland are obvious,the annual ratio of change reaches 8.0% and 9.2% during the period of study.The spatial distributing changes of land use showed that the farmland was mainly converted to forestland,grassland and orchard.