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Simulating the impacts of climate variation and land-cover changes on basin hydrology: A case study of the Suomo basin

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Science china Earth sciences 2005年第9期48卷 1501-1509页

作者： CHEN Junfeng1,2. LI Xiubin2.& ZHANG Ming2.1. institute of Remote Sensing & GIS, Peking University, beijing 100871,{2. 2. institute of geographical sciences and natural resources research, chinese Academy of sciences, beijing 100101,{2. institute of Remote Sensing & GIS Peking University Beijing China institute of geographical {2. and natural resources research Chinese Academy of Sciences Beijing Chin

Impacts of land cover changes on watershed hydrology have been a long-term academic concern with acute dispute. But little attention has been paid to such effects on mesoscale river basins, where the society has a closer link to river hydrology. The present study focuses on a mesoscale river basin, the Suomo Basin that is located on the upper reaches of the Yangtze River. Land covers in the basin in the years 1970, 1986 and 1999 were mapped. A lumped hydrologic model, CHARM, and a distributed hydrologic model, SWAT, were used to model the impacts of both land-cover change and climate variation on river runoff during the past four decades. The results show that the contribution of climate variation to the change of runoff regime makes up 60%―80%, while that of land cover changes only 2.%.

关键词： climate variation, land-cover changes, Suomo Basin, CHARM model, SWAT model.

Debris Flow Hazard Assessment Based on Support Vector Machine

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Wuhan University Journal of natural sciences 2006年第4期11卷 897-900页

作者： YUAN Lifeng 1, 2., ZHANG Youshui 3 1. institute of Mountain Hazards and Environment, chinese Academy of {2., Chengdu 610041, Sichuan, china 2. Graduate University of chinese Academy of {2., beijing 100049, china 3. institute of geographical {2. and natural {12. research, chinese Academy of {2., beijing 100101, china institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu Sichuan China Graduate University of chinese Academy of sciences Beijing China institute of geographical {2. and natural resources research Chinese Academy of Sciences Beijing China

Seven factors, including the maximum volume of once flow , occurrence frequency of debris flow , watershed area , main channel length , watershed relative height difference , valley incision density and the length ratio of sediment supplement are chosen as evaluation factors of debris flow hazard degree. Using support vector machine （SVM） theory, we selected 2.9 basic data of 37 debris flow channels in Yunnan Province as learning samples in this study. We create a debris flow hazard assessment model based on SVM. The model was validated though instance applications and showed encouraging results.

关键词： debris flow hazard assessment support vector machine (SVM)

Reconstruction of temperature series in china for the last 5000 years

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Progress in natural Science:Materials International 2006年第8期16卷 838-845页

作者： GE Quansheng, WANG Shunbing and ZHENG Jingyun (institute of geographical {2. and natural resources research, chinese Academy of {2., beijing 100101, china Graduate School of the chinese Academy of {2., {12. 100039, china) institute of geographical {2. and natural resources research Chinese Academy of Sciences Beijing 100101 China Graduate School of the chinese Academy of sciences Beijing 100039 China

A temperature series with a 100 year resolution for the last 5000 years in china has been reconstructed by using 31 longterm temperature proxy series selected from recent publications in the last 2. years. The proxy records include pollens, stalagmites, lake-sediments, peat, ice cores and historical documents. The result reveals that in the millennial scale temperature variation it was warm in 3050-2.0 BC and it was cold in 2.0 BC-1950 AD. In the above two periods there were many stages of sub-scale temperature fluctuations. The result also shows an obvious temperature discrepancy on the century to multi-century scale between the Eastern Monsoon Region, the Qinghai-Tibet Region and the Northwestern Region in 2.50 BC, 2.50 BC, 1350 BC, 950-350 BC, 50-2.0 AD, and 550 AD. A comparison between the reconstructed series of this paper and some North Hemisphere temperature series indicates that in the longterm scale change, the temperature change in china is in phrase with that of the Northern Hemisphere during the last 5000 years, while on the century to multi-century scale there are differences at the beginning and end times, which may imply that temperature change does not occur simultaneously in different regions.

关键词： temperature series the last 5000 years china.

Simulating the transfer and fate of hexachlorocyclohexane in recent 50 years in beijing, china

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Science china Earth sciences 2005年第12期48卷 2203-2213页

作者： CAO Hongying1, LIANG Tao1 & TAO Shu2.1. institute of geographical {2. and natural resources research, chinese Academy of {2., beijing 100101, china 2. Laboratory for Earth Surface Processes, Peking University, beijing 100871, china institute of geographical {2. and natural resources research Chinese Academy of Sciences Beijing China Laboratory for Earth Surface Processes Peking University Beijing China

Taking beijing as a study area, a dynamic fugacity model was used to simulate the transfer and fate of technical HCHs according to the physic-chemical properties of the studying environment and HCH isomers. Dynamic changes of the transfer fluxes and concentrations of HCH isomers during 1952.2.03 were simulated and the model results suggest good agreement between the calculated and measured concentrations of HCH isomers. During 1952.1983, the average input and output amount of HCHs through agricultural application and degradation are 130 t and 150 t respectively. The dominant transfer processes of HCHs in the study area are air-soil deposition, soil erosion and soil-air diffusion, transfer fluxes of these processes are 80 t?a?1, 16 t?a?1 and 11 t?a?1, which account for 92. of total transfer fluxes of HCHs isomers. There were approximately 2.3t HCHs in all environmental compartments of the study area during this period and 97% of which existed in soil compartment. Air and water advection became the dominant input sources of HCHs after 1984 when the application of technical HCHs was prohib-ited, concentration of HCHs quickly descended to a quite low level in several years. Total amount of HCHs isomers remaining in the study area environment now is less than 5% that before 1983, and this percentage may descend to 0.5% after 2. years by prediction.

关键词： fugacity model, hexachlorocyclohexane, compartment, transfer flux, fate.

Hyperconcentrated flows as influenced by coupled wind-water processes

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Science china Earth sciences 2005年第11期48卷 1990-2000页

作者： XU Jiongxin institute of geographical {2. and natural resources research, chinese Academy of {2. Key Laboratory of Water Cycle and Related Land Surface Processes, chinese Academy of {2., beijing 100101, china Key Laboratory of Water Cycle and Related Land Surface Processes Chinese Academy of Sciences Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China

Using data from more than 40 rivers in the middle Yellow River basin, a study has been made of the influence of coupled wind-water processes on hyperconcentrated flows. A simple “vehicle” model has been proposed to describe hyperconcentrated flows. The liquid phase of two-phase flows is a “vehicle”, in which coarse sediment particles are carried as solid-phase. The formation and characteristics of hyperconcentrated flows are closely related with the forma-tion and characteristics of this liquid-phase and solid-phase. Surface materials and geomorphic agents of the middle Yellow River basin form some patterns of combination, which have deep influence on the formation and characteristics of liquid- and solid-phases of hyperconcentrated flows. The combination of high percentages of relatively coarse material with low percentages of fine material appears in the area predominated by the wind process, where the supply of rela-tively coarse sediment is sufficient, but the supply of relatively coarse sediment is not. The com-bination of low percentages of relatively coarse material with high percentages of fine material appears in the area predominated by the water process, where the supply of fine sediment is sufficient, but the supply of fine sediment is not. In the area predominated by coupled wind-water processes appears the combination of medium percentages of coarse and fine materials, and thus both coarse and fine sediments are in relatively sufficient supply. The manner in which the mean annual sediment concentrations of liquid- and solid-phases vary with total suspended sediment concentration is different. With the increased total suspended sediment concentration, mean annual sediment concentration of liquid-phase increased to a limit and then remained constant; however, mean annual sediment concentrations of solid-phase in-creased continuously. Thus, the magnitude of total suspended sediment concentration depends on the supply conditions of relatively coarse sedime

关键词： river sediment, hyperconcentrated flows, liquid-solid two-phase flows, wind process, fluvial process, Yellow River

Spatial distribution of surface rock fragment on hillslopes in a small catchment in wind-water erosion crisscross region of the Loess Plateau

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Science china Earth sciences 2008年第6期51卷 862-870页

作者： ZHU YuanJun1,2.& SHAO MingAn1 1 institute of Soil and Water Conservation, chinese Academy of {2. and Ministry of Water resources, Northwest Agriculture and Forestry University, Yangling 712.00, china 2.institute of geographical sciences and natural resources research, chinese Academy of {2., beijing 100101, china institute of Soil and Water Conservation Chinese Academy of Sciences and Ministry of Water Resources Northwest Agriculture and Forestry University Yangling China institute of geographical {2. and natural resources research Chinese Academy of Sciences Beijing China

The cover and size distributions of surface rock fragment in hillslopes were investigated by using digital photographing and treating technique in a small catchment in wind-water erosion crisscross region of the Loess Plateau. The results indicated that the maximal cover of rock fragment was pre-sented at mid-position in steep hillslope. Rock fragment presented a general decreasing-trend along the hillslope in gentle hillslope. Rock fragment cover was positively related to gradient, rock fragment size decreased generally along the hillslope, and the size reduced with the gradient. The mean size of rock fragment was at a range of 6―2. mm in the steep hillslope, rock fragment size > 50 mm was rarely presented. The covers of rock fragment at different positions were markedly related to the quantities of rock fragment 2.50 mm accounted for 60% or more of the total area, dominating the distribution of rock fragment in the hillslopes.

关键词： wind-water erosion crisscross region of the Loess Plateau small catchment hillslope surface rock fragment cover and size

research on Jiuquan-Jiayuguan-Yumen Region's Dynamic Changing of Urbanization Based on Self-Organizing Model

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chinese Journal of Population,resources and Environment 2005年第3期3卷 22-28页

作者： Li Ming 1,2.& Fang Chuanglin 2.1 Graduate School of the chinese Academy of sciences, {2. 100039,china 2.institute of geographical sciences and natural resources research, CAS, beijing 100101, china Graduate School of the chinese Academy of sciences Beijing 100039 China institute of geographical {2. and natural resources research CAS Beijing 100101 China

Based on the self-organizing modeling principle in the dissipative structure theory, the paper regards the migration coupling between the regions as the influence factor to create the model of regional urbanization simulation and prediction, which is more practical to simulate the space-time and dynamic evolvement characteristics of regional urbanization level. According to the historical data about the population and urbanization of Jiuquan, Jiayuguan andYumen cities, the past 50 years' dynamic evolvement trend is simulated and the following 50 years' dynamic evolvement trend is predicted with the urbanization dynamic evolvement model based on the self-organizing model. The analysis of effective factors such as economic increase, resources exploitation, ecosystem construction, traffic location, national policies, population migration are given, then the reasons of the dynamic evolvement differences of the three cities' urbanization are drawn. The study suggests that the self-organizing model is fit for the simulation of Jiuquan-Jiayuguan-Yumen regional urbanization level in the past 50 years, and the departure between the stimulant and the actual data is under 5%, so it can be used to predict the urbanization future of the three cities. The predicted results show that the regional population will reach 1.074 million and the regional urbanization level will be 72.56%.

关键词： self-organizing urbanization dynamic evolvement Jiuquan-Jiayuguan-Yumen region

Relationships between tree-ring width index and NDVI of grassland in Delingha

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chinese Science Bulletin 2006年第9期51卷 1106-1114页

作者： HE Jicheng1,3 & SHAO Xuemei1,2.. institute of geographical {2. and natural resources research, chinese Academy of {2., beijing 100101, china 2. institute of Tibetan Plateau research, chinese Academy of {2., beijing 100085, china 3. Graduate School of chinese Academy of {2., beijing 100039, china institute of geographical {2. and natural resources research Chinese Academy of Sciences Beijing China Graduate School of chinese Academy of sciences Beijing China institute of Tibetan Plateau research Chinese Academy of Sciences Beijing China

Using five well-replicated Qilian juniper (Sabina przewalskii Kom.) tree-ring width index se- ries, monthly normalized difference vegetation index (NDVI) of grassland, and climatic data from 1982.to 2.01, the relationships between tree-ring width index, NDVI of grassland, and climatic data were analyzed firstly. Then, the relationship between tree-ring width index and NDVI of grassland was explored. The re- sults showed that: (1) Temperature and precipitation in June influenced tree-ring width index and NDVI of grassland deeply in Delingha. (2. There were sig- nificant relationships between five tree-ring width index series (DLH1-DLH5) and monthly NDVI of grassland from June to September, with the most significant relationship being between tree-ring width index series and NDVI of grassland in August. (3) The PC1 (the first principal component derived from DLH1-DLH5 series) exhibited good agreement with monthly NDVI of grassland in the grass growth sea- son (from June to September) and the averaged NDVI in the growth season, which was attributed to their common responses to water-supply limit in Delingha. This study may allow an increase in studying the past dynamics of grassland in Delingha in that the variation of grassland NDVI during the last millennium has been reconstructed from PC1.

关键词：圆柏祁连山 NDVI 草原年轮宽度指数

Floating Population Increase and Its Influence on the Urban Population Situation:A Case Study in beijing

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chinese Journal of Population,resources and Environment 2005年第1期3卷 27-35页

作者： Wu Peilin 1,2.& Lu Qi 2.1. Shandong University of Technology, Zibo Shandong 2.5049, china 2. institute of {2. sciences and natural resources research, chinese Academy of sciences, beijing 100101, china Shandong University of Technology Zibo Shandong 255049 China institute of geographical {2. and natural resources research Chinese Academy of Sciences Beijing 100101 China

Floating population is a special population group in china resulting from the implementation of household registration system. This paper uses a set of floating population survey data, population censuses data and statistical data to analyze the increase and influence of floating population on the urban population situations in beijing. It is found that beijing has experienced a rapid increase of floating population since the 1990s and that the increase of this group has become the key factor of the current population expansion in the city. Its distribution in the urban regions intensified and extended the suburbanization process of the capital. In addition, the population structures of sex, age, education and employment in beijing have changed to some extent due to the influx of floating population.

关键词： Floating population Household registration system (Hukou) Population expansion Suburbanization Population structure beijing