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Spatial heterogeneity of the driving forces of cropland change in china

Science china Earth {1. 2005年第12期48卷 2231-2240页

作者： liu xuhua1,2. wang jinfeng1,{2.,1 & meng bin1,2.3 1. institute of geographic sciences and natural resources research, chinese Academy of sciences, beijing 100101, china 2. Graduate School of the chinese Academy of sciences, beijing 100039, china 3. College of Arts and sciences of beijing Union University, beijing 100083, china 4. School of Forestry and Wildlife sciences, Auburn University, Auburn, Alabama, AL36849, USA institute of {1. {2. and natural resources research Chinese Academy of Sciences Beijing China Graduate School of the chinese Academy of {1. Beijing China School of Forestry and Wildlife sciences Auburn University Auburn Alabama USA College of Arts and sciences of {1. Union University Beijing China

By using digital satellite remote sensing data acquired in 1.87―1.89 and 1.99―2.00 and GIS com{1.ed with the natural and socio-economic data, this paper drew an integrated zonation of the cropland change and its driving forces in{2.. The results indicated that the cropland change in the study period was constrained by geographical factors and driven by cli-mate change as well as socio-economic system. Moreover, the regional differences of the drivers for cropland change were significant. In the midwest of{2., natural condition changes and geographical background were the main constraints and drivers, while in Eastern{2., social and economic changes and economic policies were the main driving forces. The cropland loss was nationwide. The dominant factors to cause this decrease included buildup of developing area to attract foreign capital and technologies, changes of industry structure due to urban in-fluence, the change of employment notions thanks to living standard improvement, rapid ur-banization due to the expansion of cities and towns, the diminished farming net income partly because of the global warming effects, and the rapid economic growth stimulated by the con-venient transportation system. These factors interact and interdepend with each other to cause the cropland loss in{2. recently. The reasons for the increase of cropland were primarily the cultivation and deforestation by the farmers who want to increase income. This study on the mechnism of LUCC relied on the cropland change integrated classification considering the natural or human factors both inside and outside the region, which provides a new approach to study the integrated regionalization and LUCC mechanism.

关键词： land use change, driving force, integrated classification, spatial statistics, cropland, china.

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Calculating soil moisture by remote sensing and analyzing hydrologic cycle process in the Yellow River basin

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Science china(Technological {1.) 2004年第Z1期47卷 1-13页

作者： YANG Shengtian1 & liu Changming1, 2.1. School of Environmental sciences, {2. Normal University, {2. 100875, china 2. institute of geographic Science and natural resources research, beijing 100101, china School of Environmental sciences Beijing Normal University Beijing China institute of {1. Science and {2. resources research Beijing China

Based on the AVHRR pathfinder remote sensing data, soil moisture, precipitation and evaporation during the period of 1.82.1.98, soil moisture of all layers of soil-profile (0—1.m) in the Yellow River basin over the 1. years are calculated by the remote sensing model of calculating soil water. The Yellow River basin is divided into seven subcatchments as control sections at the location of six hydrologic stations (Lanzhou, Toudaoguai, Longmen, Sanmenxia, Huayuankou and Lijin). After calculating soil moisture and obtaining runoff data and precipitation data, the dynamical features of hydrological cycle in the Yellow River basin are analyzed for the period from 1.82.to 1.88 using water balance method. The conclusions are as follows: It is feasible to calculate the soil water on the macro-scale, in the soil profile with temporal continuity by means of remote sensing and survey in land. Some values of the key water cycle factors in the Yellow River are obtained, which include the annual precipitation of 4000 km3, the evapotranspiration of 3000-3500 km3, and the soil moisture transformation of ?500- 500 km3. Consequently, we analyzed the process of the water cycle in the Yellow River over the 1. years, and the results show that the segment upstream of Lanzhou city is a relatively humid region, and the area of internal waters and the reaches of Shanshan is the most desiccated region. Therefore, the runoff in the depth process is intensive and the runoff-generating process is weak in more arid regions.

关键词： the Yellow River, soil moisture, remote sensing, hydrologic cycle.

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The study on Sanmenxia annual flow forecasting in the Yellow River with mix regression model

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Science china(Technological {1.) 2004年第Z1期47卷 118-126页

作者： JIANG Xiaohui1, liu Changming1,2. wang Yu3 & wang Hongrui1 1. beijing Normal University, beijing 100875, china 2. institute of geographic Science and natural resources, chinese Academy of sciences,{12., china 3. Reconnaissance, Planning, Design and research institute, YRCC, Zhengzhou 450003, china beijing Normal University Beijing China institute of {1. Science and {2. resources Chinese Academy of Sciences Beijing China Reconnaissance Planning Design and Research Institute YRCC Zhengzhou China

This paper established mix regression model for simulating annual flow, in which annual runoff is auto-regression factor, precipitation, air temperature and water consumption are regression factors; we adopted 9 hypothesis climate change schemes to forecast the change of annual flow of Sanmenxia Station. The results show : (1. When temperature is steady, the average annual runoff will increase by 8.3% if precipitation increases by 1.%; when precipitation decreases by 1.%, the average annual runoff will decrease by 8.2.; when precipitation is steady, the average annual runoff will decrease by 2.4% if temperature increases 1.; if temperature decreases 1., runoff will increase by 1.2.. The mix regression model can well simulate annual runoff. (2. As to 9 different temperature and precipitation scenarios, scenario 9 is the most adverse to the runoff of Sanmenxia Station of Yellow River; i.e. temperature increases 1. and precipitation decreases by 1.%. Under this condition, the simulated average annual runoff decreases by 1..8%. On the contrary, scenario 1.is the best to the enhancement of runoff; i.e. when temperature decreases 1.℃ precipitation will increase by 1.%, which will make the annual runoff of Sanmenxia increase by 1..6%.

关键词： forecast annual flow, mix regression model, Sanmenxia Station

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Reconstruction of precipitation variation from tree rings in recent 1.00 years in Delingha, Qinghai

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Science china Earth {1. 2005年第7期48卷 939-949页

作者： SHAO Xuemei1, HUANG Lei1, liu Hongbin2. LIANG Eryuan1, FANG Xiuqi3 & {2. Lili1 1. institute of geographic sciences and natural resources research, chinese Academy of sciences, beijing 100101,{12. 2. National Climate Center, beijing 100081,{12. 3. beijing Normal University, beijing 100875,{12. institute of {1. {2. Natural Resources Research Chinese Academy of Sciences Beijing 100101 China National Climate Center Beijing 100081 China beijing Normal University Beijing 100875 China

Using seven well-replicated Qilian juniper (Sabina przewalskii Kom.) ring-width chronologies developed at Zongwulong and Shalike Mts. in the northeastern part of the Qaidam Basin annual precipitation from previous July to current June in the recent 1.00 years was re- constructed for Delingha. The reconstruction can capture 63.1. of precipitation variance and the equation was stable over time. For the reconstructed precipitation, wet periods occurred in AD1.{1.—1.33 and 1.33—{1.01. whereas dry intervals in 1.{1.—1.1. and 1.34—1.41. In ad- dition, the magnitude in precipitation variation was lower before 1.30 with about 1. mm, but it increased to 30 mm during the period of 1.30 to 1.50. After 1.50, the precipitation variance de- creased again. In contrast to the increase in temperature, a decrease in annual precipitation was evident since the 1.90s. The agreement in low-frequency variation between the reconstruction and the glacier accumulation and particulate content in Dunde ice cores during the recent several hundred years suggested that the precipitation reconstructed in this study was rather reliable, and represented a regional signal. This 1.00-year reconstruction could benefit our understanding of climatic variation in decadal to century-scale in this region, and provide basic data to climate models and to prediction of future climate in the {1.st century.

关键词： northeastern part of the Qaidam Basin tree-ring width series of Qilian juniper precipitation reconstruction in 1.00 years.

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Indoor imitation experimental study on driving factors of rainfall-runoff process

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Science china Earth {1. 2005年第3期48卷 417-428页

作者： ZHANG Shifeng1, liu Changming 1, XIA Jun1, TAN Ge 1, LI Lin1, liu Caitang1, ZHOU Changqing 1 & GUO Lei2.1. {2. of geographic sciences and natural resources research, chinese Academy of sciences, beijing 100101, china 2. College of Water resources and Hydropower Engineering, Wuhan University, Wuhan 430072. china institute of {1. {2. and natural resources research Chinese Academy of Sciences Beijing China College of Water resources and Hydropower Engineering Wuhan University Wuhan China

The driving actions of rainfall-runoff process can be attributed to two aspects. The first is the influence of precipitation process, and the second is that of the ground pad. The re- search results of 1.9 indoor experiments conducted to imitate rainfall-runoff process indicate that both precipitation duration and intensity play important roles in affecting confluence lag time, which is obviously inconsistent with the traditional hypotheses. The nonlinear relationship is of great significance to the confluence curve especially when the precipitation duration is less than the total confluence time or the precipitation intensity is small. Therefore it can be concluded that the unit hydrograph (UH) can be applied to rainfall-runoff process imitation in the humid areas in the south china region. However, the UH application should be strictly modified in accordance with precipitation conditions in the arid and semiarid region of north china where the precipitation duration is short and the intensity is unstable. It will be hard to get ideal imitation results if the UH is applied blindly without considering specific conditions in the north china region. This also explains the unsatisfactory imitation results caused by using various hydrological models in the north china region. When the precipitation duration is short, and the watershed has not reached total watershed concentration, the characteristics of confluence change greatly, which reflects the actual situation in the north china region. Therefore necessary nonlinear corrections should be made when UH is applied. If the duration is longer than the total confluence time and the balance between pondage and discharge is stricken, the imitation research results will be applicable to both rainfall-runoff relation with longer duration in the south china region and the basic theoreti- cal research on runoff generation and concentration. On conditions of adequate rainfall, peak discharge is in linear relationship with inten

关键词： rainfall-runoff, driving factors, indoor imitation, experiment.

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Properties and applications of cold supersonic gas jet

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Science china(Physics,Mechanics & Astronomy) 2006年第6期49卷 709-715页

作者： ZHANG Shaofeng1,2.MA Xinwen1,2.liu Huiping2.LI bin1,2.& ZHU Xiaolong1,2.1. {2. of Modern Physics,chinese Academy of sciences,Lanzhou 730000,china 2. Graduate University of chinese Academy of sciences,beijing 100049,china institute of Modern Physics Chinese Academy of Sciences Lanzhou China Graduate University of chinese Academy of {1. Beijing China

By analyzing the formation mechanism of a supersonic gas jet,a set of equations which describe the atomic beam properties were established. The influence of initial temperature,initial pressure,background gas pressure and pumping speed was discussed in detail. A simulation program was developed based on the equations,and the results under different initial conditions were obtained. The results are in good agreement with the experimental data,and suggest that,in order to get much smaller transverse momentum in collision experiments,it is necessary to lower the initial temperature and the initial pressure of the supersonic gas jet,together with increasing the pumping speed. These results are very instructive for construction of a new generation of cold supersonic gas jets.

关键词： cold supersonic gas jet,zone of silence,nozzle,skimmer.

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Changes in hair arsenic concentration in a population exposed to heavy pollution:Follow-up investigation in Chenzhou City,Hunan Province,Southern china

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Journal of Environmental sciences 2010年第2期22卷 283-289页

作者： bin Wu,Tongbin Chen Center for Environmental Remediation,{2. of geographic sciences and natural resources research,chinese Academy of sciences,beijing 100101,{12.. Center for Environmental Remediation Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China

Follow-up investigation on hair arsenic concentration was conducted in an arsenic heavily polluted area of southern china in {1.0{1.and {1.06. The results showed that the geometric mean of hair arsenic concentration decreased from {1.95 mg/kg in {1.0{1.to 1.78 mg/kg in {1.06, when the percentage of the population with levels over 1.mg/kg only decreased from 93.4% in {1.0{1.to 80.5% in {1.06. Over this four-year period, the population with high arsenic concentrations decreased significantly while there was no obvious change in hair arsenic concentration for people who had relatively low concentrations. In terms of age distribution, young and old people had higher hair arsenic concentrations than the middle-aged. All of these results showed that it is difficult to reverse the negative impact of arsenic pollution on human health. Arsenic pollution has a long-term continuous influence on the health of local residents.

关键词： arsenic human health soil contamination hair arsenic

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Monitoring Dynamic Change of Land Cover Based on SVM and Satellite Images in Hanoi,Vietnam

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Wuhan University Journal of natural {1. 2010年第4期15卷 355-362页

作者： ZHAO Jinling1,2. liu Chuang1, 3 1. institute of {2. sciences and natural resources research, chinese Academy of sciences, beijing 100101, china 2. Graduate University of chinese Academy of sciences, beijing 100049, china 3. College of resources Science and Technology, beijing Normal University, beijing 100875, china institute of {1. {2. and natural resources research Chinese Academy of Sciences Beijing China Graduate University of chinese Academy of {1. Beijing China College of resources Science and Technology Beijing Normal University Beijing China

An integral method,combining support vector ma-chine (SVM) with remote-sensing analysis techniques,was ex-plored to monitor Hanoi’s dynamic change of land cover. The landsat thematic mapper (TM) image in 1993,the enhanced the-matic mapper plus (ETM+) image in 2.00,and the image with the charge-coupled device camera (CCD) on the china-Brazil earth {2. satellite (CBERS) in 2.08 were used. Six land-cover types,including built-up areas,woodland,cropland,sand,water body and unused land,were identified. The detected results showed visually the rapid urban expansion as well as land-cover change of Hanoi from 1993 to 2.08. There were 12.637.54 hm2.cropland de-creased between 1993 and 2.00,and 8 2.7.6 hm2.cropland de-creased between 2.00 and 2.08. Compared with cropland,wood-land firstly decreased and then increased,and the other types did not change significantly. The results indicate that CBERS dataset has the application potential in world {2. researches.

关键词： land cover the china-Brazil earth {1. satellite (CBERS) support vector machine (SVM) change detection

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Accurate Quantification of Grassland Cover Density in an Alpine Meadow Soil Based on Remote Sensing and GPS

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Pedosphere 2005年第6期15卷 778-783页

作者： liu Yan-Sui HU Ye-Cui PENG liu-Ying institute of {1. {2. and natural resources research Chinese Academy of Sciences Beijing 100101 （China） Graduate School of chinese Academy of {1. Beijing 100039 （China）

The principles of remotely estimating grassland cover density in an alpine meadow soil from space lie in the synchronous collection of in situ samples with the satellite pass and statistically linking these cover densities to their image properties according to their geographic coordinates. The principles and procedures for quantifying grassland cover density from satellite image data were presented with an example from Qinghai Lake,{1. demonstrating how quantification could be made more accurate through the integrated use of remote sensing and global positioning systems (GPS). An empirical model was applied to an entire satellite image to convert pixel values into ground cover density. Satellite data based on 68 field samples was used to produce a map of ten cover densities. After calibration a strong linear regression relationship (r2.= 0.745) between pixel values on the satellite image and in situ measured grassland cover density was established with an 89% accuracy level. However, to minimize positional uncertainty of field samples, integrated use of hyperspatial satellite data and GPS could be utilized. This integration could reduce disparity in ground and space sampling intervals, and improve future quantification accuracy even more.

关键词： alpine meadow soil grassland cover density quantitative remote sensing Qinghai Lake

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Study of attenuation depths for MODIS bands in the Bohai Sea in china

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Acta Oceanologica Sinica 2009年第5期28卷 39-48页

作者： liu Ying LI Guosheng institute of {1. {2. and natural resources research Chinese Academy of Science Beijing 100101 China Xinjiang institute of Ecology and Geogrphy Chinese Academy of Science Urumqi 830011 China

An attenuation depth is defined for remote sensing purposes as a depth above which 90% of the arising light leaving the water surface is originated. The deeper the attenuation depth, the more information of water is detectable by remote sensing, then the more precise information of water is extracted. Meanwhile, the attenuation depth is helpful to know water layer （by its thickness） from which remote sensing will be able to extract information. A number of investigators are using the moderate resolution imaging spectroradiometer （or MODIS） for remote sensing of ocean color. It is necessary to have a rough idea of the effective attenuation depth of imagery in each of the spectral bands employed by the MODIS. The attenuation depth is directly determined from MODIS data. Though analyzing the spectral distribution of the attenuation depth on 7 August 2.03 and the seasonal variation of the attenuation depth （551.nm） in the Bohai Sea indicated that： the spectral distribution of the attenuation depth for the spectral range between 400 to 700 nm is single-peak curve, and it’s similar and difference in different regions is consistent with other scholars’ results of zoning, moreover, it supports the Bohai Sea is Case 2.water; the maximum attenuation depth shifts toward longer wavelengths, liking the red shift, with increase of turbidity of water, just like the maximum attenuation depth in the outside of the northwest coast of the Bohai Sea and the Bohai Strait is at 531.m, in the central of the Bohai Sea is at 551.m, in the region controlled by the Huanghe （Yellow） River, the region impacted by the old Huanghe River, the western side of the Liaodong Bay and the eastern side of the Liaodong Bay is at 555 nm; the seasonal change of the attenuation depth is the largest in the summer, followed by the fall, and the ranking of winter and spring in different regions is distinct. The attenuation depth in different regions is dissimilar： the order of the attenuation depth in different

关键词： attenuation depth MODIS Bohai Sea

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