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  • Original Articles
    LIU Changming, LI Daofeng, TIAN Ying, HAO Fanghua, YANG Guilian
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    The paper selected the macro-scale areas of the source region of the Yellow River as an object and carried out discharge simulation with the distributed hydrological model,the SWAT model.Based on the analysis and process of DEM data,such as flow direction,a watershed borderline,a river network and sub-basins by automatically becoming,rivers,codes and areas of sub-basins,structure and topology constraint of the river network were gained with a format of grid cells.Annually and monthly measured runoff data of Tangnaihai hydrologic station from 1976~1985 were used to calibrate the simulation parameters and determine some basic parameters of the model.The simulation results are satisfactory and show that climate change is the main reason for discharge change of the source regions of the Yellow River.In twenty years of the 1980’s and the 1990’s,the discharge decrease due to climate change is 62.11×108m 3/s,which accounts for 108.72% of total discharge change,and the discharge increase due to land-cover change is 5.73×108m 3/s ,which accounts for 10.03% of that with grid cell.
  • Original Articles
    HAO Fanghua, CHEN Liqun, LIU Changming, ZHANG xuesong
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    Traditionally in the application of hydrologic/water quality (H/WQ) models, rainfall is assumed to be spatially homogeneous and is considered not to contribute to output uncertainty. The objective of this study was to assess the uncertainty induced by model outputs-runoff and sediment yield- solely due to rainfall spatial variability. The study was conducted using the SWAT model and the rainfall captured by a network of 24 rain gauges in Lushi Basin. For each rainfall event, the model was run using the rainfall captured by each rain gauge, one at a time, under the assumption of rainfall spatial homogeneity in the study area, A large uncertainty in the modeled outputs was resulted from the rainfall spatial variability. The uncertainty in the modeled outputs exceeded the input rainfall uncertainty. The uncertainty of simulated sediment yield outranges that of the runoff. The uncertainty of the simulated runoff increases with the spatial variability of rainfall. The more homogeneous of the rainfall, the more certainty of the modeled runoff. The uncertainty of the modeled sediment yield increased with the increase of spatial variability of rainfall, and the uncertainty of the modeled sediment yield is inversely related with the simulated sediment yield. Results of this study indicate that spatial variability of rainfall should be captured and used in H/WQ models in order to accurately assess the model outputs.In the application of H/WQ models, the assumption of the spatial homogeneity of the rainfall may not be valid. Spatial variability of rainfall introduces uncertainty into model outputs when uniformity of rainfall is assumed. Spatial variability of rainfall should be captured and used in H/WQ models in order to accurately assess the release and transport of pollutants. Since rainfall is a driving force behind many kinds of pollutant release and subsequent transport mechanisms, ignoring this property of rainfall in the application of H/WQ models will put a limit on the accuracy of the model results.
  • Original Articles
    YANG Shengtian, LIU Changming, WANG Pengxing
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    Soil water is a type of water resource. Although there are many methods to monitor the soil water in field, to effectually obtain data of the soil water in macro scale region is a difficult problem when evaluating water cycle. Yellow River is the second river in China, which covers an area of 752 443km 2, so it is important for the water management to calculate the soil water. On the basis of AVHRR-pathfinder data, we employed the Vegetation-Temperature Condition Index (VTCI) to monitor the land surface condition. After checking up the remote sensing data with soil water in the field, we found that VTCI is sensible to the soil water in top soil in Yellow River Basin, which agrees with other achievement. Besides, the data of soil water in field expresses obvious relation of soil water between up layer soil and down layer soil. Therefore, we set up a model to calculate soil water in soil profile (0~1m) in Yellow River Basin by combining meteorological information and remote sensing data. The data used in the research includes AVHRR-pathfinder data during 1982~1998 and soil water, precipitation and evaporation information, which were respectively monitored by 29 agriculture weather stations and 263 national weather stations. Finally, the calculated soil water was compared with survey data and checked up by the method of water balance, and the results are satisfied. It is concluded that our method can be applied in surveying soil water for soil profile in macro scale region during long time and the calculated soil water can be supplied to the research of water cycle in Yellow River Basin.
  • Original Articles
    YANG Guilian, HAO Fanghua, LIU Changming, ZHANG Xuesong
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    Baseflow, usually separated from total streamflow, is very important in many research fields. Two methods to analyze and calculate baseflow were introduced. The first method uses the water balance components from the soil and water assessment tool model (SWAT). The second method uses a digital recursive filter to separate baseflow from daily flow. The result was applied in Lushi basin located in the upper of Luohe to calibrate baseflow in SWAT model. Simulated flow was calibrated against calculated flow at Luohe (4 623km 2 ) from 1992~1996.To validate the model, calibrated and simulated monthly flow at Luohe from 1997~1998 was compared with a R 2 of 0.81 and an Ens of 0.84. Four sensitive factors, including CN_2 , RWVAPC, ESCO and EPCO, are determined after calibration and validation of the model. The rate of three-month (Aug. to Oct.) baseflow in annual total one is 46% because the floods usually took place in August and September in the study area. Comparing simulated monthly baseflow to the filtered one from 1992~1998, a good result can be gained with a R 2 of 0.76 and an E_ns of 0.75.The case study illuminates that SWAT model can simulate baseflow well, and the filter technique has the potential to provide realistic estimates of baseflow for input into regional groundwater models and a check for surface hydrologic models.
  • Original Articles
    LI Daofeng, LIU Changming
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    Geography Information System (GIS) is a decision support system,and its primary characteristic is relevant to the deposited and processed information by geographical coding,including spatial,geographical location and attributes of the land objects as to the location. The authors discussed the general application patterns of GIS in hydrology and water resources. Using relaxed combination mode of GIS and hydrological models,the GIS platform of water cycle of the Yellow River Basin was established with MS-Visual Basic visualized developing language based on one component of ESRI-MapObject GIS. The background relational database,i.e. MS-Access database, was used to construct the GIS platform of water cycle of the Yellow River Basin,automatically linking to the foregrounding interface of GIS. All kinds of data related to water cycle of the Yellow River Basin, including original data set,mid data set and ultimate data set were saved in the platform with uniform coordinate and uniform format,which supplied data support for the study of water cycle elements and process of the Yellow River Basin.
  • Original Articles
    GUO Xudong, QIU Yang, LIAN Gang, LIU Kang
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    Land quality indicators based on "press-state-response (PSR)" framework is one of the present hot-spots in land science. Fast economic growth and land degradation in China urge government and scientists to build up the indicators to monitor and evaluate land quality changes. This paper introduced the origin, concept, research plan and evaluation framework for land quality based on PSR framework, and it also summarized the new progresses in the field of international land quality indicators research. In land quality indicators project, 11 land quality indicators were proposed, which are nutrient balance, yield gap, agricultural land use intensity and land use diversity, land cover, soil quality, land degradation, agro-biodiversity, water quality, forest land quality, rangeland quality, and land contamination/pollution. Some research trends and suggestions in Chinain future were also proposed. As the national agency of land management, the Ministry of Land and Resources can make contributions to land science by the application of land quality project.
  • Original Articles
    XU Yueqing
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    From the 1970s, under the impact of natural and human factors, the groundwater table in the Hebei Plain has been declining,causing a range of geological and environmental disasters. These disasters include subsidence, seawater intrusion, salinization, desertification and so on, which have seriously threatened the ecological environment and become the key factors of restricting the socio-economic sustainable development of the Hebei Plain. This paper analyzed the causes of groundwater withdrawal from such natural factors as precipitation, surface water and temperature, and from such human aspects as over-exploitation of groundwater, building of water conservancy, improvement of crop production and enlargement of water-consuming crops. The contribution of driving forces to groundwater table drawdown was assessed through building Projection Pursuit Regression model. The result indicates that the exploitation of groundwater is the first factor, which accounts for 54.7% of groundwater withdrawal. According to the proportion of groundwater consumed by industry, agriculture and domestic, the percent of groundwater table drawdown caused by the three sectors were 6.6%, 43.7% and 4.4% respectively. The second is precipitation, with 25.6%, and the third is surface water, with 19.7%. This paper provides scientific basis for groundwater sustainable use.
  • Original Articles
    WU Kai, YUAN Zhang, XU Yuexian
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    The sown area of grain crops was 6484.4×10 3 hectares, in which the rate was 37.8% for wheat, 39.7% for maize, and the proportion among grain, cotton and oil crops was 15.9:1.0:1.6 in Hebei Province in 2002. The rate of the sown area of grain between the region and the province was 23.3% for the North Hebei Area, and 76.7% for the South Hebei Area in 2002. The ratio between the level in 2002 and in 1949 was 5.2 for the total yield of grain, which was 2435.8×10 4 tons in 2002; 5.8 for the per unit area yield of grain, which was 3756 kg per hectare in 2002; 2.4 for the per capita yield of grain, which was 362 kg in 2002. The rate of grain total yield between the region and the province was 17.2% for the North Hebei Area, and 82.8% for the South Hebei Area in 2002. According to the regression analysis and the bilateral difference modelling analysis, the grain yield in 2010 will be 3087.5×10 4 tons for the total yield, 4478 kg per hectare for the per unit area yield, and 460 kg for the per capita yield. On the basis of the gray relational analysis, the main factors affecting total yield of grain are: the per unit area yield, the general purchasing price index of farm produce and sideline products, the total power of agricultural machinery, the electricity consumed in rural area, the consumption of chemical fertilizer in farmland, and the effective irrigated area. According to our estimation, if the total power of agricultural machinery is 8989×10 4kw, the electricity is consumed 240.8×10 8kwh, the consumption of chemical fertilizer 356.1×10 4 tons, and the effective irrigated is area 4549.2×10 3 hectares in 2010, the per unit area yield of grain will be 4664 kg per hectare; if the rate of the sown area is 0.387 for wheat, and 0.439 for maize, the per unit area yield will be 4387 kg per hectare.
  • Original Articles
    LIU Zhiwu, DANG Anrong, LEI Zhidong, HUANG Yugang
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    Being used widely in eco-environment study, Land Surface Temperature (LST) is an important parameter for land-air exchange process. Traditional observations and calculations are based on a point, while remote sensing makes it possible to calculate the region LST. At present, most of LST retrieval algorithms are found on Split-Window method with thermal infrared remote sensing data, such as NOAA/AVHRR, MODIS, Landsat TM, and so on. ASTER(Advanced Spaceborne Thermal Emission and Reflection Radiometer) is a comparatively new source of remote sensing data and it is launched in 1999. ASTER has higher spatial and spectral resolution,and provides more detailed information than NOAA/AVHRR, Landsat TM, etc, which helps to improve the precision of LST retrieval. Taking an ASTER remote sensing data of the typical study region at Awati, Xinjiang Province as the data source,based on the methodology of Temperature/Emissivity Separation algorithm, LST is retrieved by using three modules of ADE (Alpha Derived Emissivity), Ratio Method and MMD (Maximum-Minimum Difference). And then, the main error sources of this model are briefly analyzed, which are from theory hypothesis of model, atmosphere effect, emissivity and characteristics of the sensor systems. According to the calculation and analysis, the conclusion is that the advanced Temperature/Emissivity Separation algorithm is effective, and using ASTER data to retrieve LST can obtain more precise results and will have a perspective future.
  • Original Articles
    PENG Jian, WANG Yanglin, JIU Juan, LI Weifeng, DING Yan
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    The ecological development of shoaly land is one of the research topics on shoaly land in China. But till now, there is little research on scale in shoaly land research. In this paper, we first made a brief review of exploitation of shoaly land in China. Then we made a research on spatial scale issues of exploitation of shoaly land. It is thought there are great differences in researches on ecological development of shoaly land in different spatial scales. In the scale of plot, the core research is about agro-technology; in the scale of farm, micro-economy is the core research; and in the scale of region, the core research is about the ecological rationality of spatial combination of different development types of shoaly land. Then we outlined some problems on recent exploitation of shoaly land in China in different spatial scales. In the scale of region, the main problems are the lack of policy assistance and integrated management, regional environmental pollution and ecological destroy, regional freshwater absence, and frequent coastal disaster. In the scale of farm, the main problems are the lack of financing, weakness of shoaly land research, low benefit of resource development, waste of resources, and resource exhaustion. In the scale of plot, the main problems are unenlightened technology of resource development, and low land quality. At last, we analyzed the main characteristics of ecological development models on shoaly land in China in the scale of region, farm, and plot. We also analyzed the ecological process of each model and its socio-economic benefits of such ecological development models as stepped development of shoaly land, dike-pond system, multipurpose use of salt pans, and vertical culture in shrimp ponds.
  • Original Articles
    SONG Linhua, WANG Jing, LIN Junshu, LI Fuhai, ZHANG Yonglan
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    The Longkong Cave, including the underground river and dry passages decorated by the solutional features and carbonate speleothems, is one of the well known show caves in Southeastern China. It developes in the Lower Permian Qixia limestone with siliceous layers and concretions. The Qixia limestone is contacted by faults with Lower Permian Tongzhiyan sandstone and shale with coal mines, Wenbishan sandtone and shales and Devonian silicarenite and conglomerate rock. The surface valleys developed along the faults. The Qixia limestone was metamorphosed by the Late Yanshan granite intrusion. Topograpgically, The sandstone and shale with coal and the granite on the mountain and the Qixia limestone on the lower slope. The surface water and groundwater from the sandstone and shale with coal and othe noncarbonates terrains flows into or down to the limestone. A part of limestone has been exposed as the noncarbonate rocks,which have been removed away. The fissure spring water discharging from the Tongzhiyan formation is with pH values in the range from 3.78 to 4.73, 240 mg/l of SO_4 -2 anions; the water with pH of 6.78~7.25 and lower contents of Ca 2+ and HCO_3 - sources from other noncarbonate rock terrains. These exotic waters, expecially with sulphuric acid aqueous,strongly dissolve the limestone to form the Longkong cave system. The endogenetic water penetrates into soil covering on the limestone from the rainwater and dissolves the CO_2 produced by vegetation roots breath, organism decomposion and biofunction of soil fauna and mcrobe to form the carbonatic acid aqueous. When the water flows into the limestone,it dissolves the limestone to enlarge the fissures and passages. The Longkong Cave is the typical genetic model for cave development by the sulphuric and carbonatic acid aqueous from the exotic and endogenetic waters.
  • Original Articles
    LONG Shaoqiu
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    The development of the medium-sized and small cities in the metropolitan fringe has special characteristics. The particular location and function of the medium-sized and small cities in the metropolitan fringe make it especially important that they should develop harmoniously with the big cities they are tied to. Recently,to improve the urbanization level, some administration measures such as rezoning by combining the surrounding countries with the big cities as their districts are adopted broadly in China. With these changing development backgrounds,the development strategies of the medium-sized and small cities in the metropolitan fringe have to be adjusted too. By taking Zengcheng to the east of Guangzhou as a study area,this paper discusses the development strategies of the medium-sized and small cities in the metropolitan fringe detailedly from the aspects of industry development,spatial development, environment protection and the construction of infrastructures,which explores the way of sustainable development of these special cities and has important practical and theoretical meaning in present China.