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Effect of climatic change on snowmelt runoffs in mountainous regions of inland rivers in Northwestern china

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Science china Earth {1. 2006年第8期49卷 881-888页

作者： WANG Jian1.& LI Shuo2.1. Cold and Arid Regions Environmental and Engineering Research Institute, {1. academy of {2., Lanzhou 730000, china 2. College of Geography, Nanjing Normal University, Nanjing 2.0097, china 1. Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China 2. College of Geography Nanjing Normal University Nanjing 210097 China

Climatic change has significant impacts on snow cover in mid-latitude mountainous re- gions, in the meantime, spatial and temporal changes of snow cover and snowmelt runoffs are con- sidered as sensitive indicators for climatic change. In this study, the upper Heihe Watershed in the Qilian Mountains was selected as a typical area affected by snow cover and snowmelt runoffs in northwestern china. The changes in air temperatures, precipitation, snowfall and spring snowmelt runoffs were analyzed for the period from 1.56 to {1.01. The results indicate that climatic warming was apparent, particularly in January and February, but precipitation just fluctuated without a clear trend. The possible changes of snowmelt runoffs in the upper Heihe watershed in response to a warming of 4℃ were simulated using Snowmelt Runoff Model (SRM) based on the degree-day factor algorithm. The results of the simulation indicate that a forward shifting of snow melting season, an increase in water flows in earlier melting season, and a decline in flows in later melting season would occur under a 4℃ warming scenario.

关键词： climatic changes, snowmelt runoff, SRM model, upper Heihe Watershed, simulating.

Size-dependent hydroxyl radicals generation induced by SiO_2.ultra-fine particles: The role of surface iron

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Science china Chemistry 2009年第7期52卷 1033-1041页

作者： SHANG Yu1. ZHU Tong1. LI Yi1.2.& ZHAO JinCai3 1.College of Environmental {1. and Engineering, Peking University, Beijing 1.0871. china 2.{2. academy of meteorological {1., Beijing 1.0871. china 3 Institute of Chemistry, {2. academy of {1., Beijing 1.0871. china 1. College of Environmental sciences and Engineering Peking University Beijing 100871 China 2. chinese academy of meteorological sciences Beijing 100871 China 3. Institute of Chemistry Chinese Academy of Sciences Beijing 100871 China

Oxidative stress and hydroxyl radicals (·OH) play important roles in adverse health effects caused by inhalable ambient air particles (PM1.). The ultra-fine fraction of PM1. has been hypothesized as one of the critical contributors to ·OH generation. Both in vivo and in vitro studies have shown that ultra-fine particles (UFPs) or nano-particles generate more ·OH than larger particles with identical mass and composition. Both the surface area and surface-adsorbed redox-active metals have been suggested as factors to determine the oxidative capacity of UFPs. In this study, the ·OH-generating capability of dif-ferent sizes of SiO2.particles was investigated in order to determine which factor influences particle-induced ·OH generation. The amount of ·OH generated in both acellular and cellular systems was quantified using a capillary electrophoresis method following exposure to SiO2.particles with diameters of 1., 1.0, and 500 nm. The amount of ·OH was strongly dependent on particle size, and a significant enhancement was observed only with 1. nm particles. Further studies indicated a close association between ·OH and iron ion concentration (R2.= 0.81.0} p1.. Washed particles, with their surface iron being removed, did not generate ·OH. The iron-containing leachate from these washings was able to enhance ·OH production as untreated particles did. Therefore, the presence of adsorbed iron on the surface of the SiO2.particles is presented as a possible mechanism of UPFs-induced ·OH generation. The SiO2.acted as an inert substrate, and the surface of ultra-fine SiO2.particles acted as a carrier for iron.

关键词： ultra-fine particles nano-particles ·OH oxidative stress size-effect

N_2. emissions from agricultural soils in the North {1. Plain: the effect of chemical nitrogen fertilizer and organic manure

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Journal of Environmental sciences 2000年第4期12卷 463-468页

作者： DONG Yun\|she 1.2.3 , Dieter Scharffe 2. Manfred Domroes 3, QI Yu chun 1. ZHANG Shen 1.(1. Institute of Geographic sciences and Natural Resources Research, chinese {2. of sciences, Beijing 1.01.1. china E\|mail: dongys@*** 2. M 中科院地理科学与资源所北京 1 0 0 1 0 Max- Planck-Institute of Chemistry 德国 Mainz 550 2 0 Mainz University 德国 Mainz 550 99

An enclosed chamber technique was used to measure N 2. emissions from intensively agricultural soils of the North {1. Plain during the periods of 1.95—1.96 and 1.97—1.98, to reflect distinct components of winter wheat and summer maize growing seasons. The results showed that the continuous application of fertilizer in agricultural soils increased N\-2. emissions by a factor of 2..1.2..1. the calculated annual chemical N fertilizer\|transformed N\-2.\|N emissions was 0.67%. Our results indicated that the application of organic manure also had a significant influence on soil N 2. emissions, which combined with the use of chemical N increased about 2.% in a year. It was calculated that there were about 0.1.% N of organic manure transformed as N 2. N. Annual mean N 2. emission from our study area of fertilized soils was estimated to be 57.1.μgN 2./(m 2.h). A weak correlation was also found between N 2. emissions and soil available nitrogen content NH + 4.

关键词： N_2. emissions the North china Plain agricultural soils chemical nitrogen organic manure

New technique to control in situ oxygen fugacity in water-free high-pressure system──Using Cu-O as an example

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chinese Science Bulletin 1998年第16期43卷 1353-1358页

作者： LI Heping 1. XIE Hongsen 1. GUO Jie 1. ZHANG Yueming 1.XU Zuming 1.and XU Ji’an 2.1. Institute of Geochemistry, {1. academy of {2., Guiyang 550002. china 2. Institute of Earth {2., Taiwan 1.52., china Institute of Geochemistry Chinese Academy of Sciences Guiyang China Institute of Earth sciences Taiwan China

Through inserting a solid oxygen-specific electrolyte (YSZ) inside and exerting an electrical power of direct current outside between the sample and oxygen reservoir (an solid oxygen buffer), oxygen was driven by the power from the cathodic electrode area into the positive electrode area at high temperature and high pressure. In this way, the oxygen fugacity in the sample was in situ controlled independently of temperature and pressure. By using Cu-O system as an example, this technique was proved to be successful.

关键词： in situ control of oxygen fugacity water-free system high temperature and high pressure.

Temperature variations recovered from tree-rings in the middle Qilian Mountain over the last millennium

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Science china Earth {1. 2005年第4期48卷 521-529页

作者： LIU Xiaohong1.2. QIN Dahe1. SHAO Xuemei , CHEN Tuo1.& REN Jiawen1.0}1. Cold and Arid Regions Environmental and Engineering Research Institute, chinese academy of {2., Lanzhou 730000, china 2. Institute of Geographical {2. and Natural Resources Research, chinese academy of {2., Beijing 1.01.1. china 1. Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences 730000 Lanzhou China 2. Institute of Geographical {1. and Natural Resources Research Chinese Academy of Sciences 100101 Beijing China

Based on the cross-dated tree-ring samples collected from the middle Qilian Moun- tain, a standard ring-width chronology had been developed, which covered the period AD 1.00 to 2.00. The correlations between the chronology and climatic records from the nearby {1. stations indicated that temperature was the dominant climatic factor for tree growth at upper timberline, and the most important climatic factor for the tree growth in the area was the mean temperature from previous December to current April. The temperature variations recovered from the ring-width data showed a cold period during the “Little Ice Age” and the con- tinuous warming during the twentieth century. Comparison between the ring-width chronology and δ1.O records from the Dunde ice core in the Qilian Mountain indicated that there was a con- sistent trend in both time series. A significant correlation existed between our ring-width chro- nology and the Northern Hemispheric temperature, suggesting that the climate changes in the Qilian Mountain were not only driven by regional factors, but also responsive to the global cli- mate.

关键词： middle Qilian Mountain, tree-ring width chronology, temperature variations.

Study of thin cloud removal method for CBERS-02.image

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Science china(Technological {1.) 2005年第S2期48卷 91-99页

作者： MA Jianwen1. GU Xingfa1. FENG Chun2.& GUO Jianning2.1. Institute of Remote Sensing Application, chinese academy of {2., Beijing 1.01.1. china 2. china Center for Resource Satellite Data and Applications, Beijing 1.0073, china 1. Institute of Remote Sensing Application Chinese Academy of Sciences 100101 Beijing China 2. {1. Center for Resource Satellite Data and Applications 100073 Beijing China

The china Brazil Earth Resources Satellite (CBERS) ended the dependence on foreign satellites. Along with the series of CBERS and the enhancement of satellite applications, it is necessary to search correlative data processing methods. Because cloud appears in the atmosphere, an image with clear sky conditions is often hard to obtain. How to remove cloud is an important sector of increasing image quality. An improved homomorphism filtering method is adopted to remove thin cloud qualitatively at first, and all bands are selected to classify pixels. Based on the fact that visible band images contain more aerosol effects than infrared bands, visible bands are used to determine clear or hazy regions and the reflectances of different surface classes in clear regions are calculated. At last the mean reflectance of the same classes in clear and hazy regions is matched to remove cloud. The image visual effect is improved; meanwhile, the ground reflectance is retrieved to meet the needs of remote sensing quantification.

关键词： CBERS-02 cloud removal surface reflectance mean reflectance matching.

Ecological Footprint and Ecological Security Evaluation in the Upper Min River Basin

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Wuhan University Journal of Natural sciences 2005年第4期10卷 641-646页

作者： TU Jian-jun 1. 2.1. School of Resources and Environment Science, Southwest {1. Normal University, Chongqing 40071., {1. 2. Institute of Mountain Hazards and Environment, {2. academy of sciences, Chengdu 61.041. Sichuan, {1. Southwest china Normal University School of Resources and Environment Science Chongqing China (GRID:grid.263906.8) chinese {1. of {2. Institute of Mountain Hazards and Environment Chengdu Sichuan China (GRID:grid.9227.e) (ISNI:***)

On the basis of the ecological footprint (EF) model, this paper studied theecological security in the Upper Min River Basin ecosystem. The result shows that with 2. 038 2.hm^2.er capita ecological capacity (0. 42. 2.hm^2.higher than per capita EF) ,and 1.5 82. hm^2.ecologysurplus , the ecosystem in Upper Min River is generally secure at present. But the arable land isoverweighed and omens an eco-security crisis. Meanwhile, problems such as low forest coverage rate,severe loss of water and soil,enlargement of arid-valley area, frequent occurrence of mountainhazards and degradation of pastures have been major threats to the eco-security of this region. Thecalculation result of ten-thousand-yuan ( RMB) GDP shows that the use of natural resources isextensive, and there will be a rapid increase tendency of EF in the future. In order to maintain thepresent eco-security, the ways of use natural resources must be improved in the Upper Min RiverBasin.

关键词： ecological security ecological footprint ecological capacity quantitativeevaluation the Upper Min River Basin

Environmental characteristics of Mid-Holocene recorded by lacustrine sediments from Lake Daihai, north environment sensitive zone, china

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Science china Earth {1. 2006年第9期49卷 968-981页

作者： SUN Qianli1.2. ZHOU Jie1. SHEN Ji3, CHEN Peng1.2. WU Feng1.2.& XIE Xiuping1.2.1. State Key Lab of Loess and Quaternary Geology, Institute of Earth Environment, chinese academy of {2., Xi’an 71.075, china 2. Graduate University of chinese academy of {2., Beijing 1.0039, china 3. Nanjing Institute of Geography and Limnology, chinese academy of {2., Nanjing 2.0008, china 1. State Key Lab of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi’an 710075 China 2. Graduate University of {1. academy of {2. Beijing 100039 China 3. Nanjing Institute of Geography and Limnology Chinese Academy of Sciences Nanjing 210008 China

Climate proxies, such as total organic carbon and nitrogen (TOC, TN), carbonate content (CaCO3), grain-size and pollen of the sediment core retrieved from enclosed Lake Daihai which lies in the north china environment sensitive zone are analyzed to reconstruct the environment evolution of the area based on high-resolution radiocarbon chronology. The results reveal that the TOC and TN contents of the sediments correlate well with pollen percentage and pollen flux variations during the Holocene, and both reach their peak values simultaneously at 6.7―3.5 ka BP (calendar age, 7.6―3.6 ka BP). Since 6.7 ka BP, both the CaCO3 and organic matter contents of the core have simultaneous variations, and their high values also occur during 6.7―3.5 ka BP. While during 9.0―6.7 ka BP (calendar age, 1.―7.6 ka BP) relatively lower level of organic matter content and pollen flux corre- spond to the higher level of carbonate content. The above relations suggest that during 6.7―3.5 ka BP, the productivity and effective precipitation were greatly improved in the lake drainage area, and this would probably strengthen the hydrodynamic conditions, enhancing organic matter, pollen and carbonate inputs from terrestrial sources. Such processes would account for the enrichment of both organic matter and carbonate in the sediments. While during 9.0―6.7 ka BP, the lower level of or- ganic matter, pollen flux but high carbonate content show depressed productivity and declined vege- tation coverage. The higher carbonate content at this stage would have probably resulted from the higher evaporation ratio of the lake water under relatively drier climate conditions. Therefore, it is in- ferred that during 6.7―3.5 ka BP, the climate was more humid with abundant rainfalls and vegetation was more flourishing in the Lake Daihai area. This can be seen as Holocene Climate Optimum (HCO). As a result, this has evident discrepancies with the traditional notion that the HCO occurs at Early Holocene or early Mid

关键词： Lake Daihai, Mid-Holocene, lacustrine sediments, environmental characteristics.

Evaluation criteria for gas source rocks of marine carbonate in china

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Progress in Natural Science:Materials International 2005年第9期15卷 810-817页

作者： WANG Zhaoyun1.*, ZHAO Wenzhi1.and WANG Yunpeng2.1. Research Institute of Petroleum Exploration & Development,Petro{1., Beijing 1.0083, {1. 2. Guangzhou Institute of Geochemistry, {2. academy of sciences, Guangzhou 51.640, {1.) Research Institute of Petroleum Exploration & Development PetroChina Beijing 100083 China. Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China

Hydrocarbon generating and expulsion simulation experiments are carried out using samples artifically matched between the acid-dissolved residue of relatively low-maturity limestone and the original sample. This work makes up for the insufficiency of source rock samples with high abundance of organic matters and low maturity in china. The organic carbon content of the 1. prepared samples varies between 0.1.% and 0.74%. Pyrolysis data and simulation experiment results of hydrocarbon generating and expulsion, which were obtained by a high-temperature and high-pressure open system, indicate that the lower limit of organic carbon content for marine carbonate rock to generate and expel hydrocarbons is 0.{1.%—0.31.. In combination with the numerical analysis of organic carbon in marine carbonate rocks from Tarim Basin, Sichuan Basin, Ordos Basin and North china, as well as the contribution of these gas source rocks to the discovered gas pools, we think that the organic carbon criterion for carbonate gas source rocks should be 0.3%.

关键词： carbonate gas source rock gas-generating efficiency evaluation criteria simulation experiment.