检索结果-南通市图书馆

Local and non-local sources of airborne particulate pollution at beijing——The ratio of Mg/Al as an element tracer for estimating the contributions of mineral aerosols from outside beijing

引用

Science china Chemistry 2005年第3期48卷 253-264页

作者： HAN Lihui1, ZHUANG Guoshun1,2,3, SUN Yele1 & wang Zifa3 1. The Center for atmospheric Environmental Study, Department of Chemistry, beijing Normal University, beijing 100875, china 2. Center for atmospheric Chemistry Study, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, china 3. LAPC/NZC, institute of atmospheric physics, CAS, beijing 100029, china The Center for atmospheric Environmental Study Department of Chemistry Beijing Normal University Beijing China Center for atmospheric Chemistry Study Department of Environmental Science & Engineering Fudan University Shanghai China institute of atmospheric physics CAS LAPC/NZC Beijing China

A new element tracer technique has firstly been established to estimate the contri-butions of mineral aerosols from both inside and outside beijing. The ratio of Mg/Al in aerosol is a feasible element tracer to distinguish between the sources of inside and outside beijing. Mineral aerosol, inorganic pollution aerosol mainly as sulfate and nitrate, and organic aerosol are the major components of airborne particulates in beijing, of which mineral aerosol accounted for 32%―67% of total suspended particles （TSP）, 10%―70% of fine particles （PM2.5）, and as high as 74% and 90% of TSP and PM2.5, respectively, in dust storm. The sources from outside beijing contributed 62% （38%―86%） of the total mineral aerosols in TSP, 69% （52%―90%） in PM10, and 76% （59%―93%） in PM2.5 in spring, and 69% （52%―83%）, 79% （52%―93%）, and 45% （7%―79%） in TSP, PM10, and PM2.5, respectively, in winter, while only20% in summer and autumn. The sources from outside beijing contributed as high as 97% during dust storm and were the dominant source of airborne particulates in beijing. The contributions from outside Bei-jing in spring and winter are higher than those in summer, indicating clearly that it was related to the various meteorological factors.

关键词： mineral aerosol local sources non-local sources dust storm re-suspended dust element tracer technique.

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Simulation Experiments of Land Surface Physical Processes and Ecological Effect over Different Underlying Surface

引用

地球科学进展 2004年第S1期19卷 15-20页

作者： LIU Shu-hua~(1,2), JIANG Hao-yu, HU Fei~2 LIU Hui-zhi~2 LIANG Fu-ming~1, wang Jiang-hua~1(1. Group of Atmosphere Boundary Layer and turbulence, Ministry Laboratory of Storm and Drought Flood Damage, Department of atmospheric sciences the School of physics Peking University, beijing 100871, china 2. State Key Laboratories of Atmosphere physics and Chemistry, institute of atmospheric physics, chinese academy of Science, beijing 100029, china)

Based on the existing Land Surface Physical Process Models(Deardorff, Dickinson, LIU, Noilhan, Seller, ZHAO), a Comprehensive Land Surface Physical Process Model (CLSPPM) is developed by considering the different physical processes of the earth's surface-vegetation-atmosphere system more completely. Compared with SiB and BATS, which are famous for their detailed parameterizations of physical variables, this simplified model is more convenient and saves much more computation time. Though simple, the feas...

关键词： Comprehensive land surface Physical process model (CLSPPM) Simulation experiment Land surface physical process Ecological effect.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Estimate of productivity in ecosystem of the broad-leaved Korean pine mixed forest in Changbai Mountain

引用

Science china Earth sciences 2006年第S2期49卷 74-88页

作者： wang Miao, GUAN Dexin, wang Yuesi, HAO Zhanqing &LIU Yaqin institute of Applied Ecology, chinese academy of sciences, Shenyang 110016, china institute of atmospheric physics, chinese academy of sciences, beijing 100029, china Eastern Liaoning University, Dandong 118003, china

We measured soil, stem and branch respiration of trees and shrubs, foliage photosynthesis and respiration in ecosystem of the needle and broad-leaved Korean pine forest in Changbai Mountain by LI-6400 CO2 analysis system. Measurement of forest microclimate was conducted simultaneously and a model was found for the relationship of soil, stem, leaf and climate factors. CO2 flux of different components in ecosystem of the broad-leaved Korean pine forest was estimated based on vegetation characteristics. The net ecosystem exchange was measured by eddy covariance technique. And we studied the effect of temperature and photosynthetic active radiation on ecosystem CO2 flux. Through analysis we found that the net ecosystem exchange was affected mainly by soil respiration and leaf photosynthesis. Annual net ecosystem exchange ranged from a minimum of about -4.671μmol·m-2·s-1 to a maximum of 13.80μmol·m-2·s-1, mean net ecosystem exchange of CO2 flux was -2.0μmol·m-2·s-1 and 3.9μmol·m-2·s-1 in winter and summer respectively (mean value during 24 h). Primary productivity of tree, shrub and herbage contributed about 89.7%, 3.5% and 6.8% to the gross primary productivity of the broad-leaved Korean pine forest respectively. Soil respiration contributed about 69.7% CO2 to the broad-leaved Korean pine forest ecosystem, comprising about 15.2% from tree leaves and 15.1% from branches. The net ecosystem exchange in growing season and non-growing season contributed 56.8% and 43.2% to the annual CO2 efflux respectively. The ratio of autotrophic respiration to gross primary productivity (Ra:GPP) was 0.52 (NPP:GPP=0.48). Annual carbon accumulation underground accounted for 52% of the gross primary productivity, and soil respiration contributed 60% to gross primary productivity. The NPP of the needle and broad-leaved Korean pine forest was 769.3 gC·m-2·a-1. The net ecosystem exchange of this forest ecosystem (NEE) was 229.51 gC·m-2·a-1. The NEE of this forest ecosystem acquired by eddy cova

关键词： carbon balance eddy covariance technique primary productivity net ecosystem exchange of CO2 flux the broad-leaved Korean pine forest.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Low-frequency fluctuations in the magnetosheath: Double Star TC-1 and Cluster observations

引用

Science china(Technological sciences) 2008年第10期51卷 1626-1638页

作者： DU Jian1,2 wang Chi1, SONG Pu3,4 & ZHANG TieLong5 1 State Key Laboratory of Space Weather, Center for Space Science and Applied Research, chinese academy of sciences, beijing 100190, china 2 Graduate School, chinese academy of sciences, beijing 100049, china 3 Earth, Environmental and atmospheric sciences Department, University of Massachusetts, Lowell, Mas-sachusetts MA 01854, USA 4 Center for atmospheric Research, University of Massachusetts, Lowell, Massachusetts MA 01854, USA 5 Space Research institute, Austrian academy of sciences, Graz A-8010, Austria State Key Laboratory of Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing China Graduate School Chinese Academy of Sciences Beijing China Earth Environmental and Atmospheric Sciences Department University of Massachusetts Lowell USA Center for atmospheric Research University of Massachusetts Lowell USA Space Research institute Austrian Academy of Sciences Graz Austria

The magnetic field variations are analyzed in the range of time periods from 4 s to 240 s in the magnetosheath observed by the Double Star TC-1 and Cluster in 2004. The characteristics of the magnetic field fluctuations are strongly controlled by the angle between the upstream interplanetary magnetic field (IMF) and the normal of the bow shock. Generally speaking, the magnetic field fluctuations in the quasi- parallel magnetosheath are more intense than those in the quasi-perpendicular ones. Almost purely compressional waves are found in the quasi-perpendicular magnetosheath. With the increase of the local plasma β, both the magnitude and direction of the magnetic field fluctuate more intensely. There exists an inverse correlation between the local temperature anisotropy T⊥/T|| and the plasma β.

关键词： low-frequency fluctuations magnetosheath MHD instabilities

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

CO_2 efflux from different forest soils and impact factors in Dinghu Mountain, china

引用

Science china Earth sciences 2005年第Z1期48卷 198-206页

作者： ZHOU Cunyu, ZHOU Guoyi, ZHANG Deqiang, wang Yinghong & LIU Shizhong Dinghushan Forest Ecosystem Research Station, chinese academy of sciences, Guangzhou 510650, china institute of atmospheric physics, chinese academy of sciences, beijing 100029, china Dinghushan Forest Ecosystem Research Station Chinese Academy of Sciences Guangzhou 510650 China institute of atmospheric physics Chinese Academy of Sciences Beijing 100029 China

CO2 fluxes from soils and related environmental factors were measured in three forest ecosystems of Dinghu Mountain using static chamber-gas chromatograph technique for one year. The seasonal pattern of CO2 flux, contribution of litter on total CO2 flux and the correlations of CO2 flux with soil temperature and soil water content were examined for each type of forest. The results were given as followings: (1) The seasonal patterns of CO2 flux from soil of the three types of forest were similar, with a higher CO2 flux in rainy season than in dry season. The comparative relations of mean annual CO2 fluxes between the three sites were expressed as:monsoon forest ＞ mixed forest ＞ pine forest. (2) CO2 fluxes from litter decomposition in monsoon forest, mixed forest and pine forest accounted for 24.43%, 41.75% and 29.23% of the corresponding total CO2 fluxes from forest floor, respectively. (3) Significant relationships were found between CO2 fluxes and soil temperatures at 5 cm depth for the three types of forest, which could be best described by exponential equations. The calculated Q10 values based on soil temperature at 5 cm depth ranged from 1.86 to 3.24. More significant relationships were found between CO2 fluxes and soil water content when the annual variation coefficients of soil moisture were higher.

关键词： CO2 flux, litter decomposition, Q10, soil moisture.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Seasonal dynamics of CO_2 fluxes from subtropical plantation coniferous ecosystem

引用

Science china Earth sciences 2006年第S2期49卷 99-109页

作者： LIU Yunfen, YU Guirui, WEN Xuefa, wang Yinghong, SONG Xia, LI Ju, SUN Xiaomin, YANG Fengting, CHEN Yongrui & LIU Qijing institute of Geographic sciences and Natural Resources Research, chinese academy of sciences, beijing 100101, china institute of atmospheric physics, chinese academy of sciences, beijing 100029, china College of Resources and Environmental Science, china Agricultural University, beijing 100094, china 1. institute of Geographic sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China 2. institute of atmospheric physics Chinese Academy of Sciences Beijing 100029 China 3. College of Resources and Environmental Science China Agricultural University Beijing 100094 China

As one component of chinaFLUX, the measurement of CO2 flux using eddy covariance over subtropical planted coniferous ecosystem in Qianyanzhou was conducted for a long term. This paper discusses the seasonal dynamics of net ecosystem exchange (NEE), ecosystem respiration (RE) and gross ecosystem exchange (GEE) between the coniferous ecosystem and atmosphere along 2003 and 2004. The variations of NEE, RE and GEE show obvious seasonal variabilities and correlate to each other, i.e. lower in winter and drought season, but higher in summer; light, temperature and soil water content are the main factors determining NEE; air temperature and water vapor pressure deficit (VPD) influence NEE with stronger influence from VPD. Under the proper light condition, drought stress could decrease the temperature range for carbon capture in planted coniferous, air temperature and precipitation controlled RE; The NEE, RE, and GEE for planted coniferous in Qianyanzhou are -387.2 gC·m-2 a-1,1223.3 g C·m-2 a-1, -1610.4 g C·m-2 a-1 in 2003 and -423.8 g C·m-2 a-1, 1442.0 g C·m-2 a-1, -1865.8 g C·m-2 a-1 in 2004, respectively, which suggest the intensive ability of plantation coniferous forest on carbon absorbing in Qianyanzhou.

关键词： plantation eddy covariance photosynthesis respiration drought stress.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Natural interdecadal weakening of East Asian summer monsoon in the late 20th century

引用

Science Bulletin 2005年第17期 109-115页

作者： JIANG Dabang1, 2 & wang huijun1 1. Nansen-Zhu International Research Center, institute of atmospheric physics, chinese academy of sciences, beijing 100029, china 2. Key Laboratory of Regional Climate-Environment Research for Tem-perate East Asia, chinese academy of sciences, beijing 100029, china

Based on the reanalysis data throughout 1948―2002 as derived from the United States National Centers for Environmental Prediction and National Center for Atmos-pheric Research, it is revealed that East Asian summer mon-soon (EASM) intensity weakens on an interdecadal timescale since the mid-1960s, and twice interdecadal jumps are re-corded in the EASM intensity index series in the late 20th century, respectively occurring in the mid-1960s and mid- to late 1970s. Six globally coupled atmosphere-ocean models’ outputs under the SRES A2 greenhouse gas and aerosol emission scenario, provided by the IPCC Data Distribution Center and the Hadley Center for Climate Prediction and Research, are then systematically examined. It follows that the above EASM weakening is not closely related to synchro-nizing anthropogenic global warming, and, therefore, it should be qualitatively natural change process. Over the 21st century, the EASM intensity is likely increased slightly by continually intensified greenhouse effect relative to the late 20th century.

关键词： East Asian summer monsoon interdecadal weakening global warming natural change.

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

The retrieval of two-dimensional distribution of the earth's surface aerodynamic roughness using SAR image and TM thermal infrared image

引用

Science china Earth sciences 2004年第12期47卷 1134-1146页

作者： ZHANG Renhua 1 ,wang Jinfeng 1 ,ZHU Caiying 1,2 ,SUN Xiaomin 1 & ZHU Zhilin 1 1.institute of Geographical sciences and Natural Resources,chinese academy of sciences,beijing 100101,china 2.institute of Surveying and Mapping,Information Engineering University of the chinese People’s Liberation Army,Zhengzhou 450052,china chinese academy of sciences Institute of Geographical Sciences and Natural Resources Beijing China Information Engineering University of the chinese People’s Liberation Army Institute of Surveying and Mapping Zhengzhou China

After having analyzed the requirement on the aerodynamic earth’s surface rough- ness in two-dimensional distribution in the research field of interaction between land surface and atmosphere, this paper presents a new way to calculate the aerodynamic roughness using the earth’s surface geometric roughness retrieved from SAR (Synthetic Aperture Radar) and TM thermal infrared image data. On the one hand, the SPM (Small Perturbation Model) was used as a theoretical SAR backscattering model to describe the relationship between the SAR back- scattering coefficient and the earth’s surface geometric roughness and its dielectric constant re- trieved from the physical model between the soil thermal inertia and the soil surface moisture with the simultaneous TM thermal infrared image data and the ground microclimate data. On the basis of the SAR image matching with the TM image, the non-volume scattering surface geo- metric information was obtained from the SPM model at the TM image pixel scale, and the ground pixel surface’s equivalent geometric roughness—height standard RMS (Root Mean Square) was achieved from the geometric information by the transformation of the typical to- pographic factors. The vegetation (wheat, tree) height retrieved from spectrum model was also transferred into its equivalent geometric roughness. A completely two-dimensional distribution map of the equivalent geometric roughness over the experimental area was produced by the data mosaic technique. On the other hand, according to the atmospheric eddy currents theory, the aerodynamic surface roughness was iterated out with the atmosphere stability correction method using the wind and the temperature profiles data measured at several typical fields such as bare soil field and vegetation field. After having analyzed the effect of surface equivalent geo- metric roughness together with dynamic and thermodynamic factors on the aerodynamic surface roughness within the working area, this paper first establishe

关键词： surface geometric roughness, aerodynamic surface roughness, SAR backscattering model, moisture retrieval model, roughness transformation model.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Dynamical framework with blocking topography coordinates for atmospheric GCM and its validation

引用

chinese Science Bulletin 2003年第S2期48卷 9-17页

作者： LIN Zhaohui~1, ZHANG Ming~(1,2), LIANG Danqing~(1,2) wang Aihui~1, ZHANG Dongling~1 & ZENG Qingcun~1 1. ICCES, institute of atmospheric physics, chinese academy of sciences. beijing 100029. china 2. College of Meteorology. PLA University of Science and Technology, Nanjing 211101. china chinese Acad Sci Inst Atmospher Phys ICCES Beijing 100029 Peoples R China PLA Univ Sci & Technol Coll Meteor PLA Nanjing 211101 Peoples R China

The dynamical framework with Blocking To-pography Coordinates (hereafter, BTC), which is suited tohandle the steep topography for the atmospheric generalcirculation models, is presented in this paper, together withits validation results. The integral properties of both the dif-ferential and finite-difference equations for the BTC dy-namical core are: gross mass conservation, quadratic con-servation for advection terms, Coriolis force does not changethe kinetic energy, conservation of total available energy. Theimproved nonlinear iteration scheme is utilized for thetime-integration. The energy conservation for BTC dynami-cal core is validated by using the integration results from9-layer and 21-layer version respectively. Comparison resultsshow that, the changes of the kinetic energy and total avail-able potential energy during the integration are quite closefor both the BTC dynamical framework and the dynamicalframework of IAP 9-level and IAP 21-level AGCM, and thismay suggest that the BTC dynamical core can be used forlong-term integration with good computational ***, the BTC dynamical core has the advantageover the terrain following (sigma) coordinates in its betterrepresentation of the influence of the large-scale topographyon the atmospheric general circulation. Finally, the correct-ness and reasonableness of the BTC dynamical core has beenfurther proved by the numerical simulation of the topogra-phy influence on the quasi-stationary planetary wave with21-layer version of BTC dynamical framework.

关键词： blocking topography coordinates atmospheric general circulation model dynamical framework.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Influences of double aerial CO_2 concentration on plant root surface area and viability and infection intensity of vesicular-arbuscular mycorrhizal fungi

引用

chinese Science Bulletin 1999年第1期44卷 63-64页

作者： wang Xingfen, LI Shiyi, BAI Kezhi KUANG Tingyuninstitute of Botany, chinese academy of sciences, beijing 100093, china Corresponding author institute of Botany Chinese Academy of Sciences Beijing China

Using recently developed methods for root research, an investigation initiated concerning effects of doubled atmospheric CO2 concentration on root surface area and infection of vesicular-arbuscular mycorrhizal （VAM） fungi in seedlings of maize, wheat and soybean. Results showed that doubled CO2 concentration significantly extended root system surface area and promoted VAM fungal infection intensity and viability. However, interspecific variation existed in these responses. It is suggested that plant community succession would be changed due to altered characteristics of roots among species in the future climate.

关键词： doubled CO2 concentration root surface area VAM infection plant community succession.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：