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Impact of land-use change on hydrological processes in the Maying River basin, china

Science china Earth sciences 2006年第10期49卷 1098-1110页

作者： WANG Genxu1,3, ZHANG Yu2. LIU Guimin2.& CHEN Lin3 1. Institute of mountain Hazards and Environment, chinese Academy of {2., Chengdu 610041, china 2. Cold and Arid Regions Environmental and Engineering Research Institute, chinese Academy of {2., Lanzhou 730000, china 3. Resource and Environment School, Lanzhou University, Lanzhou 730000, china Institute of mountain Hazards and Environment Chinese Academy of Sciences Chengdu China Resource and Environment School Lanzhou University Lanzhou China Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou China

Since the 1960s, dramatic changes have taken place in land-use patterns characterized by the persistent expansion of cultivated land and a continuous decrease in natural woodland and grassland in the arid inland river basins of china. It is very important to assess the effects of such land-use changes on the hydrological processes so vital for water resource management and sustainable development on the catchment scale. The Maying River catchment, a typical arid inland watershed located in the middle of the Hexi Corridor in northwest china, was the site chosen to investigate the hydrological responses to land-use changes. The annual runoff, base flow, maximum peak flow, and typical seasonal runoff in both spring and autumn flood periods were selected as the variables in the hydrological processes. Statistical-trend analysis and curvilinear regression were utilized to detect the trends in hydrological variables while eliminating the climatic influence. The relationship between cultivated land-use and hydrological variables was analyzed based on four periods of land-use variation data collected since 1965. A runoff model was established composed of two factors, i.e., cultivated land use and precipitation. The impact of land use changes, especially in the large ar- eas of upstream woodland and grassland turned into cultivated lands since 1967, has resulted in a mean annual runoff decrease of 2..12., a base flow decline of 35.32., a drop in the maximum peak discharge of 35.77%, and mean discharge decreases in spring and autumn of 36.05% and 2..87% respectively, of which the contribution of cultivated land expansion to the influence of annual runoff amounts to 77%-80%, with the contribution to the influence of spring discharge being 73%-81%, and that to the influence of base flow reaching 62.-65%. Thus, a rational regulation policy of land use patterns is vitally important to the sustainable use of water resources and the proper development of the entire catchment.

关键词： land-use change, arid inland river catchment, hydrological process, impact, Maying River.

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Prediction of Debris-flow Danger Area by Combining Hydrological and Inundation Simulation Methods

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Journal of mountain Science 2011年第1期8卷 1-9页

作者： CUI Peng Key Laboratory of mountain Hazards and Earth Surface Process Chinese Academy of Sciences Chengdu 610041 China Institute of mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 China Graduate School of chinese Academy of sciences Beijing 100049 China

Debris flows have caused serious human casualties and economic losses in the regions strongly affected by the Ms8.0 Wenchuan earthquake of 2.o8. Debris flow mitigation and risk assessment is a key issue for reconstruction. The existing methods of inundation simulation are based on historical disasters and have no power of prediction. The rain- flood method can not yield detailed flow hydrograph and does not meet the need of inundation simulation. In this paper, the process of water flow was studied by using the Arc-SCS model combined with hydraulic method, and then the debris flow runoff process was calculated using the empirical formula combining the result from Arc-SCS. The peak discharge and runoff duration served as input of inundation simulation. Then, the dangerous area is predicted using kinematic wave method and Manning equation. Taking the debris flow in Huashiban gully in Beichuan County, Sichuan Province, china on 2. Sep. 2.o8 as example, the peak discharge of water flow and debris flow were calculated as 35.52.m3·s-1 and 2.5.66 m3·s-, with error of 4.15% compared to the measured values. The simulated area of debris-flow deposition was 161,500 m2. vs. the measured area of 144,097 m2. in error of 81.75%. The simulated maximum depth was 12.3 m, consistent with the real maximum depth between lO and 15 m according to the field survey. The minor error is mainly due to the flow impact on buildings and variations in cross-section configuration. The present methodology can be applied to predict debrisflow magnitude and evaluate its risk in other watersheds inthe earthquake area.

关键词： Debris flow Arc-SCS model Inundation simulation Risk analysis Wenchuan earthquake

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Time Evolution of the Turnover Frequency for Diagnosis of the Coronal Magnetic Field

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chinese Journal of Astronomy and Astrophysics 2006年第1期6卷 113-119页

作者： Guang-Li Huang Purple mountain {2. Chinese Academy of Sciences Nanjing 210008

Two impulsive microwave bursts observed by Owens-Valley Solar Arrays （OVSA） are studied. The fast time variation of the turnover frequency in these bursts is quite different from the constant value in the earlier conclusion. The observational turnover frequencies are consistent with the calculations using the non-thermal gyrosynchrotron radiation model. We find the turnover frequency may play an important role for calculating the coronal magnetic field on the basis of Dulk and Marsh＇s approximations.

关键词： Sun: radio radiation -- Sun: corona- Sun: magnetic fields

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Optical results of the black hole microquasar SS 433

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Science china(Physics,Mechanics & Astronomy) 2010年第S1期53卷 153-156页

作者： LI Hui1,2.& YAN JingZhi1,3 1 Purple mountain {2.,chinese Academy of sciences,nanjing 2.0008,china 2.Graduate University of chinese Academy of sciences,Beijing 100049,china 3 Service d’Astrophysique,CEA Saclay and University Paris Diderot,91191 Gif-sur-Yvette,France Purple mountain {2. Chinese Academy of Sciences Nanjing China Graduate University of chinese Academy of sciences Beijing China Service d’Astrophysique CEA Saclay and University Paris Diderot Gif-sur-Yvette France

We present optical spectroscopic observations of SS 433 during different precessional and orbital *** 2.04,2.07 and 2.08 data provide us a good chance to study the variability of the Hα line at different orbital phases for nearly the same disk *** data show that the Hα of SS 433 usually had a symmetric profile between orbital phases 0.2.-0.75,while an asymmetric structure with a strong red peak was observed for other orbital *** suggest that the orbital variability of Hα emission is connected with accretion flow from the donor star to the accretion *** addition,we attribute the dramatic increase of Hα emission during our 2.07 observational run,which had a time scale of one day,to the emergence of strong jets.

关键词： high-mass X-ray binary black hole spectroscopy outflow wind relativistic jet

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An alternative evolution scenario for OAO 1657-415 and IGR J18483-0311

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Science china(Physics,Mechanics & Astronomy) 2010年第S1期53卷 130-134页

作者： LIU QingZhong1,2.LI Hui1,3 & YAN JingZhi1,2.1 Purple mountain {2.,chinese Academy of sciences,nanjing 2.0008,china 2.Service d’Astrophysique,CEA Saclay and University Paris Diderot,91191 Gif-sur-Yvette,France 3 Graduate University of chinese Academy of sciences,Beijing 100049,china Purple mountain {2. Chinese Academy of Sciences Nanjing China Service d’Astrophysique CEA Saclay and University Paris Diderot Gif-sur-Yvette France Graduate University of chinese Academy of sciences Beijing China

The relation between the spin period and the orbital period in high-mass X-ray binaries is ***/X-ray binaries and SG/X-ray binaries occupy different areas in Corbet's *** two SG/X-ray binaries,IGR J18483-0311 and OAO 1657-415,however,appear to occupy a transition region between Be/X-ray binaries and wind-fed SG/X-ray *** can be understood by noting that the neutron stars in the two SG/X-ray binaries have not reached their equilibrium spin periods when the donors evolved off the main ***,we provide an alternative scenario to explain their location in Corbet's diagram:the SG/X-ray binaries are the descendants of Be/X-ray binaries,*** supergiants in these systems were formed from O-type emission line stars instead of normal main-sequence ***,we suggest that there are two types of SG/X-ray binaries:one is directly evolved from a normal OB-type main sequence and neutron star system without an X-ray history,and the other evolved from a Be/X-ray binary with an X-ray history.

关键词： high-mass X-ray binary pulsar Corbet’s diagram stellar evolution

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Validation of three infiltration models on purple soil under simulated rainfall

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Progress in Natural Science:Materials International 2007年第9期17卷 1059-1066页

作者： Wang Yukuan1,2.Fu Bin1,3,Xu Pei1,2.Wang Daojie1,2.Wang Xiantuo1,3 and Wang Yongqiang1,3(1.Key Laboratory of mountain Surface Process and Hazards,chinese Academy of Seiences,Chengdu 610041,{2. 2.Institute of mountain Hazards and Environment,chinese Academy of sciences,Chengdu 610041,{2. 3.Graduate University of the chinese Academy of sciences,Beijing 100049,{2.) Key Laboratory of mountain Surface Process and Hazards Chinese Academy of Sciences Chengdu 610041 China Institute of mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 China Graduate University of the chinese Academy of sciences Beijing 100049 China

So as to find models suitable for the prediction of water infiltration in purple soil,infiltration rates simulated by three popular empirical infiltration models,Horton model,Kostiakov model,and the modified Kostiakov model,were compared by using those observed results on slope in purple soil under rainfall simulation.2. sets of infiltration data were divided into two parts for parameter estimation and validation *** performance of the three infiltration models was evaluated with the Nash and Sutcliffe efficiency *** results show that the percent for Nash and Sutcliffe efficiency greater than 0.7 is about 69.7% for the Horton model,and 48.48%,and 54.55% for the Kostiakov model and the modified Kostiakov model,*** model is better than Kostiakov model and the modified Kostiakov model in most rain events in the ***,Kostiakov model is still suitable for reasonable prediction of the infiltration in purple soil sloping farmland because fewer parameters are ***,rainfall intensity has significant effects on the parameter values used in the simulation *** simulation results can be improved by choosing suitable parameters according to the rainfall intensity.

关键词： infiltration model sloping farmland purple soil rainfall simulation

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Statistical study of EUV and X-ray transient brightenings

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Research in Astronomy and Astrophysics 2010年第7期10卷 696-706页

作者： Jing-Wei Li Hui Li Purple mountain {2. Chinese Academy of Sciences Nanjing 210008 China

Using the visual inspection and base difference method and data from the X-ray Telescope （XRT） onboard Hinode and TRACE with improved spatial and temporal resolution, we selected 48 X-ray transient brightenings （XTBs） and 2.7 EUV transient brightenings （ETBs） to study the connection between these two types of transient brightenings （TBs）. These ETBs and XTBs have smaller areas （8.42.Mm^2.and 36.3 Mm^2. respectively, on average） and shorter durations （9.0 min and 6.9 min, respectively, on average） than previous studies. These XTBs show three types of morphological structure： point-like, single-loop and multiple-loop. We find only 2.% of the ETBs have corresponding XTBs while the other 80% have no X-ray signatures at all. This is presumably due to the small amount of released energy, which is not enough to heat the plasma to coronal temperatures which produce X-ray emission rather than being due to the limitation of spatial resolution and temperature sensitivity of the X-ray instrument. These small ETBs may significantly contribute to the coronal heating.

关键词： Sun X-rays, gamma rays -- Sun UV radiation -- Sun corona

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The Gyrosynchrotron Radiation Spectrum in a Nonuniform Source

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chinese Journal of Astronomy and Astrophysics 2006年第2期6卷 260-264页

作者： Ai-Hua Zhou Purple mountain {2. Chinese Academy of Sciences Nanjing 210008

Effects of the energy spectral index δ, low energy cutoff E0 and number density N of energetic electrons on gyrosynchrotron spectrum are investigated for a model source with a nonuniform magnetic field. It is found that the flux density SVT of the x-mode and o-mode systematically increase with increasing E0, N and with decreasing δ. The peak frequency of the spectrum, vp, also systematically increases as increasing E0 and N, but it may not depend on δ. The gyrosynchrotron radiation in the nonuniform case is polarized predominately in the x-mode at v ≥ 3 GHz. A sense reversal of circular polarization also occurs but at much lower frequencies （v ≤ 3 GHz）. The reversal frequency also increases with increasing E0 and N, but it perhaps is independent of δ.

关键词： Sun: flares - Sun: radio radiation

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Soil Evolution Features of Debris Flow Waste-Shoal Land

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Journal of mountain Science 2009年第2期6卷 181-188页

作者： CUI Peng GE Yonggang ZHUANG Jianqi WANG Daojie Key Laboratory of mountain Hazards and Land Surface Processes Chinese Academy of Sciences Chengdu 610041 China Institute of mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 China Graduate University of chinese Academy of sciences Beijing 100049 China

The reclamation and utilization of debris flow waste-shoal land plays an important role in the mitigation and control of debris flow hazards, which thus contributes a lot to the exploitation of insufficient land resources in mountainous areas and the reduction of losses caused by debris flow. The aim of this paper is to discuss the features and mechanism of soil evolution of debris flow waste-shoal land so as to search for the available modes of its reclamation and utilization. The Jiangjiagou Ravine, a typical debris flow ravine, was selected to study soil evolution features of debris flow waste-shoal land based on the analysis of soil physicochemical properties and soil microstructure. It was found that the soil evolution rates of debris flow waste-shoal land varied with different modes of reclamation. For the land which had been reclaimed for less than 10 years, soil evolved most rapidly in paddy fields, and more rapidly in dry farmland than in naturally restored waste-shoal land. For the land which had been used for more than 10 years, the soil evolution rates of dry farmland, naturally restored waste-shoal land and paddy farmland decreased in the file. For the same utilization period of time, significant differences were recognized in soil evolution features under different modes of reclamation. Analysis data showed that soil clay content, soil thickness, the psephicity of skeleton particles and contents of microaggregates (2.mm) in paddy farmland were all highest. Soil nutrients and porosity of dry farmland were better than those of paddy farmland and naturally restored waste-shoal land, and those of paddy farmland were superior to those of naturally restored waste-shoal land. Paddy farmland characterized by rapid pedogenesis, stable evolution and high utilizability was the priority candidate for the reclamation and utilization of debris flow waste-shoal land.

关键词： Debris flow waste-shoal land Reclamation mode Utilization time Soil properties Soil microstructure

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Grain size record of microparticles in the Muztagata ice core

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Science china Earth sciences 2006年第1期49卷 10-17页

作者： WU Guangjian1,2. YAO Tandong1,2. XU Baiqin1,2. LI Zheng2. TIAN Lide1,2. DUAN Keqin2.& WEN Linke2.1. Laboratory of Environment and Process on Tibetan Plateau, Institute of Tibetan Plateau Research, chinese Academy of sciences, Beijing 100085, {2. 2. Key Laboratory of Cryosphere and Environment, Jointly Established by Cold and Arid Regions Environmental and Engi-neering Research Institute and Institute of Tibetan Plateau Research, chinese Academy of sciences and chinese Academy of Meteorological sciences, {2. Meteorological Administration, Lanzhou 730000, {2. Laboratory of Environment and Process on Tibetan Plateau Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing China Key Laboratory of Cryosphere and Environment Jointly Established by Cold and Arid Regions Environmental and Engineering Research Institute and Institute of Tibetan Plateau Research Chinese Academy of Sciences and Chinese Academy of Meteorological Sciences China Meteorological Administration Lanzhou China

The dust transport and sediment characteristics are discussed based onanalysis of mi-croparticle size and size distribution in the Muztagata ice core at 6350 m a.s.I. Thefiner particles with diameter of 1—5 μm are the dominant fraction in number, while middle andcoarse particles mainly contribute to the total volume. The lognormal distribution characteristicscan be seen for some high concentration samples, showing that model size and standard variation aregreater than that in the Greenland ice cores. However, size-volume distribution of some lowconcentration samples is abnormal. Those distributions reflect the dust deposit process in highmountain glaciers at mid-low latitudes and show differences from those in polar ice sheet.

关键词： Muztagata, ice core, microparticle, dust, size distribution.

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