检索结果-南通市图书馆

The significance of lake sediments geochemistry in environmental reconstruction of south Hongshan Lake, northwestern Tibetan Plateau during the past 150 years

在线全文

学校读者我要写书评

暂无评论

Journal of geographical sciences 2000年第3期10卷 65-71页

作者： CHEN Ling, ZHU Li-ping, ZHANG Qing-song (institute of Geographic sciences and {2. {3. research, Chinese academy of sciences, beijing 100101, china)

A 107cm piston-core (SHC-2. was drilled at the site with water depth of 5m in South Hongshan Lake, northwest Tibet in 1998. Based upon the 0.72.m/a of modern sedimentary rate that was tested by 2.0Pb method and also calibrated by 13.Cs method as well as the 1cm interval sample cutting level, a lake sedimentary record of 150-yr old and with a resolution of 1.4 yrs was obtained. Ratio of geochemistry contents (TOC, TN, CaCO3. and concentrations of trace elements such as B, Sr, Ba, Ca, Mg, K, Na, Al, Ti, Cu, Zn, Fe, Mn, Ni, Cr, V, Pb, etc were analyzed. The values of TOC, TN, C/N, CaCO3. Sr/Ba and Fe/Mn had clear environmental significance and well reflected the environmental changes. Geochemical multi-proxies of lacustrine sediments from SHC-2.core showed that the environmental changes in this area during the past 150 years could be reconstructed as follows: Stage 1 (1850s-1880s) was a cold period; Stage 2.(1880s-192.s) was a warm period. But the variation of lake water volume was stable in the two periods. Stage 3.(192.s-1950s) was a fluctuant and transitional period in temperature, but there were a short cold period in the 192.s and a warm period in the 193.s. Stage 4 (1950s-) showed a warming tendency, though there existed a cold period from the mid 1970s to the end of the 1980s. In the view of general trend in the past 150 years, South Hongshan Lake was shrinking gradually. It showed that, from the comparison with the Guliya ice core and meteorological records of adjacent weather stations, there is difference in the variations of temperature and precipitation among different regions and altitudes in Tibetan Plateau. It is necessary to search multi-scale and high-resolution records for environmental reconstruction and comparison.

关键词： Kunlun Mts. south Hongshan Lake lake sediments geochemistry environmental changes

Modeling the climate effects of different subregional uplifts within the Himalaya-Tibetan Plateau on Asian summer monsoon evolution

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2012年第35期57卷 4617-4626页

作者： ZHANG Ran 1,JIANG DaBang 1,2.3.LIU XiaoDong 4 & TIAN ZhiPing 2.5 1 Climate Change research Center,Chinese {2. of sciences,{3. 10002.,china 2.Nansen-Zhu International research Centre,institute of Atmospheric Physics,Chinese {2. of sciences,{3. 10002.,china 3.Key Laboratory of Regional Climate-Environment research for Temperate East Asia,Chinese {2. of sciences,{3. 10002.,china 4 State Key Laboratory of Loess and Quaternary Geology,institute of Earth Environment,Chinese {2. of sciences,Xi’an 710075,china 5 Graduate University of Chinese {2. of sciences,{3. 100049,china Climate Change research Center Chinese Academy of Sciences Beijing China Nansen-Zhu International research Centre Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Key Laboratory of Regional Climate-Environment research for Temperate East Asia Chinese Academy of Sciences Beijing China State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi’an China Graduate University of Chinese academy of sciences Beijing China

Considering the different uplifting time of different subregions of the Himalaya-Tibetan Plateau(TP),a series of numerical simulations have been conducted with the Community Atmosphere Model(CAM4) developed at the National Center for Atmospheric research to explore the effects of the phased tectonic uplift of the Himalaya-TP on the evolution of Asian summer *** results show that the uplifts of the Himalaya and northern TP significantly affect the evolutions of South Asian summer monsoon and northern East Asian summer monsoon *** is,the tectonic uplift of the Himalaya intensifies the South Asian summer monsoon circulation and increases the precipitation in South Asia,whereas the uplift of the northern TP intensifies the northern East Asian summer monsoon circulation and increases the precipitation in northern East *** with previous simulations,current comparative analyses of modeling results for different subregional uplifts within the Himalaya-TP help deepen our understanding of the evolutionary history of Asian monsoons.

关键词：青藏高原隆升喜马拉雅亚洲季风高原气候夏季季风次区域隆起演化建模

Adjoint method for the optimum planning of industrial pollutant sources

在线全文

学校读者我要写书评

暂无评论

Science china Earth sciences 2005年第8期48卷 1270-1279页

作者： LIU Feng1,2. HU Fei2.& ZHU Jiang2.1. College of Environmental sciences, Peking University, beijing 100871,{2. 2. LAPC, {3. of Atmospheric Physics, Chinese academy of sciences, beijing 10002.,{2. College of Environmental sciences Peking University Beijing China LAPC Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China

The optimum planning of industrial pollutant sources, which optimizes the economic object without violating environmental constraints, is an important and hard task to be conquered. In this paper, an adjoint method is developed to solve the problem. The penalty function is in-troduced to deal with the environmental inequality constraints, and Lagrange function is con-structed to derive the adjoint equation and the gradient of the object function. In this means, the gradient of the object function can be calculated by solving the adjoint equation, and the infor-mation from the gradient is used to make the object function descend and approach to an optimal solution after some iterations. A two-dimensional, simplified model is used for numerical experi-ments. The theoretical derivations are verified by the results of the experiments. Furthermore, the adjoint method is shown to be of excellent convergence and efficiency, which is adaptive to the fast development of air quality numerical models and super computers.

关键词： optimum planning, industrial pollutant sources, adjoint equation, penalty function, gradient.

Spatial and temporal variation of soil moisture near the interface of high/low stands

在线全文

学校读者我要写书评

暂无评论

Journal of geographical sciences 2000年第4期10卷 109-120页

作者： Liu Su-xia, Mo Xing-guo (institute of Geographic sciences and {2. {3. research, Chinese academy of sciences, beijing 100101, P. R. china) 中科院地理科学与资源所北京

In order to explore the spatial variability of soil moisture near the interface of high/low stands, an experiment was conducted at Luancheng Experimental Station, Chinese academy of sciences, Hebei,{2. from May to June, 1996. By analyzing the observed soil moisture data, it shows that there exists an obvious turning point of soil moisture pattern from one side of the interface to another. The effect of drier soil closer to the interface in winter wheat field is obvious, which is mainly due to the better ventilation condition near the interface in winter wheat filed than in alfalfa field. The irrigation in large scale is one of the most important factors to control the spatial pattern of soil moisture while the small scale human disturbing activity, such as the stealing event occurred during our observation, does not change the spatial pattern of soil moisture obviously. Latent heat, calculated by Bowen ratio method based on our observed micrometeorological data, is shown larger in alfalfa than that in winter wheat both at earring stage from May 8 to 10 and mature stage from June 11 to 14. This fact, together with the larger ground temperature and a little bit larger wind velocity in lower layer, explains that the soil is drier in alfalfa than in winter wheat from May 8 to 10. While for the period from June 11 to 14, irrigation's effect changes the {3. interrelationship of soil moisture with meteorology and ground temperature.

关键词： soil moisture interface of alfalfa/winter wheat field

Relationship between land cover and monsoon interannual variations in east Asia

在线全文

学校读者我要写书评

暂无评论

Journal of geographical sciences 2002年第1期12卷 42-48页

作者： XIANG Bao, LIU Ji-yuan (institute of Geographic sciences and {2. {3. research, CAS, beijing 100101, china) institute of Geographic sciences and {2. {3. research CAS 北京 100101

Asian monsoon have multiple forms of variations such as seasonal variation, intra-seasonal variation, interannual variation, etc. The interannual variations have not only yearly variations but also variations among several years. In general, the yearly variations are described with winter temperature and summer precipitation, and the variations among several years are reflected by circulation of ENSO events. In this study, at first, we analyze the relationship between land cover and interannual monsoon variations represented by precipitation changes using Singular Value Decomposition method based on the time series precipitation data and 8km NOAA AVHRR NDVI data covering 1982.to 1993.in east Asia. Furthermore, after confirmation and reclassification of ENSO events which are recognized as the strong signal of several year monsoon variation, using the same time series NDVI data during 1982.to 1993.in east Asia, we make a Principle Component Analysis and analyzed the correlation of the 7th component eigenvectors and Southern Oscillation Index (SOI) that indicates the characteristic of ENSO events, and summed up the temporal-spatial distribution features of east Asian land cover’s inter-annual variations that are being driven by changes of ENSO events.

关键词： east Asian land cover monsoon climate interannual variations Singular Value Decomposition ENSO events Principle Component Analysis

Evaluation of 10 plant barcodes in Bryophyta (Mosses)

在线全文

学校读者我要写书评

暂无评论

Journal of Systematics and Evolution 2010年第1期48卷 36-46页

作者： 1,2.Yan LIU 3.Hai-Fei YAN 4 Tong CAO 3.Xue-Jun GE 1({2. of Applied Ecology, Chinese academy of sciences, Shenyang 110016,{3.) 2.Graduate University of the Chinese academy of sciences, beijing 100049,{3.) 3.Key Laboratory of Plant resources Conservation and Sustainable Utilization, South{3. Botanical Garden, Chinese academy of sciences, Guangzhou 510650,{3.) 4(College of Life & Environment sciences, Shanghai Normal University, Shanghai 2.02.0},{3.) (institute of Applied Ecology Chinese Academy of Sciences Shenyang 110016 China) (Graduate University of the Chinese academy of sciences Beijing 100049 China) (Key Laboratory of Plant resources Conservation and Sustainable Utilization South China Botanical Garden Chinese Academy of Sciences Guangzhou 510650 China) (College of Life & Environment sciences Shanghai Normal University Shanghai 200234 China)

DNA barcoding is a molecular tool that uses a standardized DNA region to identify *** preliminary study reported here is the first attempt to specifically focus on universality and attributes of candidate barcodes across a wide systematic range of *** tested eight previously proposed plant barcoding regions(atpF-atpH, ITS2. matK, psbK-psbI, rbcL, rpoB, rpoC1, and trnH-psbA) and two popular phylogenetic markers(rps4 and trnL-trnF of cpDNA) in 49 moss species and 9 liverwort species, representing half of the orders in moss *** ITS2. rbcL, rpoC1, rps4, trnH-psbA and trnL-trnF regions showed good universality, and therefore the efficacy of these loci as DNA barcodes was further evaluated in 3. mosses and 2.liverworts, each of which included two to three individuals per *** five loci, ***, rpoC1, rps4, trnH-psbA and trnL-trnF, were easy to amplify and sequence and showed significant inter-specific genetic variability, making them potentially useful DNA barcodes for *** best performing single loci were the rbcL and rpoC1 coding *** loci showed equivalent performance and combinations of them did not greatly increase their discrimination *** addition, phylogenies generated from each of the separate regions and multi-locus combinations by using best-fit and Kimura 2.parameter models were compared, but no significant difference was found.

关键词： Bryophyta DNA barcoding rbcL rpoC1 rps4 trnH-psbA trnL-trnF.

Application of the moist vorticity vector in the analysis of a heavy rainfall event in North china

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in natural Science:Materials International 2007年第12期17卷 1457-1465页

作者： Zhao Yu1,2.3. Wang Jianguo4 and Xue Deqiang2.1. Laboratory of Cloud-Precipitation Physics and Severe Storms, institute of Atmospheric Physics, Chinese {2. of sciences, {3. 10002., china 2. Shandong Provincial Meteorological Observatory, Jinan 2.003., china 3. Graduate University of Chinese {2. of sciences, {3. 10003., china 4. Shandong Provincial Meteorological Bureau, Jinan 2.003., china) Laboratory of Cloud-Precipitation Physics and Severe Storms Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Shandong Provincial Meteorological Observatory Jinan 250031 China Graduate University Chinese Academy of Sciences Beijing 100039 China Shandong Provincial Meteorological Bureau Jinan 250031 China

The moist vorticity vector (MVV), defined as (ζa×▽qv)/ρ introduced by Gao et al. is used to study a heavy rainfall event in North china. The MVV has zonal, meridional and vertical components in a three-dimensional framework. Analysis of domain-mean and mass-integrated quantities shows that the variation of the vertical component of the MVV closely follows the variation of the cloud hydrometeors, with a linear correlation coefficient of 0.95, indicating that the vertical component of the MVV is strongly associated with midlatitude convection. Further analysis shows that the vertical component of the MVV reflects the interaction between the horizontal vorticity and the horizontal specific humidity gradient, which can associate dynamic and thermodynamic processes with cloud microphysical processes. Thus, this study can help to understand how the interaction between circulations and clouds aids the development of convection, and the MVV can be used to trace the development and evolution of heavy rainfall.

关键词： moist vorticity vector heavy rainfall modeling study.

Automated detection of lunar craters based on object-oriented approach

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2008年第23期53卷 3699-3704页

作者： YUE ZongYu1,2.3.4, LIU JianZhong3.& WU GanGuo2.1 {2. of Remote Sensing Application, Chinese academy of sciences,{3., china 2.6} University of Geosciences (beijing), beijing 100083. china 3.National Astronomical Observatories of Chinese academy of sciences, beijing 100012. china 4 Department of Geological sciences, The University of Texas at San Antonio, San Antonio, TX 782.9, U.S.A institute of Remote Sensing Application Chinese Academy of Sciences Beijing China china University of Geosciences ({2.) Beijing China National Astronomical Observatories of Chinese academy of sciences Beijing China

The object-oriented approach is a powerful method in making classification. With the segmentation of images to objects, many features can be calculated based on the objects so that the targets can be distinguished. However, this method has not been applied to lunar study. In this paper we attempt to apply this method to detecting lunar craters with promising results. Craters are the most obvious features on the moon and they are important for lunar geologic study. One of the important questions in lunar research is to estimate lunar surface ages by examination of crater density per unit area. Hence, proper detection of lunar craters is necessary. Manual crater identification is inefficient, and a more efficient and effective method is needed. This paper describes an object-oriented method to detect lunar craters using lunar reflectance images. In the method, many objects were first segmented from the image based on size, shape, color, and the weights to every layer. Then the feature of "contrast to neighbor objects" was selected to identify craters from the lunar image. In the next step, by merging the adjacent objects belonging to the same class, almost every crater can be taken as an independent object except several very big craters in the study area. To remove the crater rays diagnosed as craters, the feature of "length/width" was further used with suitable parameters to finish recognizing craters. Finally, the result was exported to ArcGIS for manual modification to those big craters and the number of craters was acquired.

关键词：自动化检测月球环形山地貌

A revision of Clematis ***(Ranunculaceae)

在线全文

学校读者我要写书评

暂无评论

Journal of Systematics and Evolution 2009年第6期47卷 552-580页

作者： ~(1,2.Wen-Jing YANG ~1Liang-Qian LI~* ~3.ei XIE 1(State Key Laboratory of Systematic and Evolutionary Botany,institute of Botany,Chinese {2. of sciences,{3. 100093.china) 2.Graduate University of Chinese {2. of sciences,{3. 100049,china) 3.Southwestern{12. Germplasm Bank of Wild Species,Kunming institute of Botany Chinese {2. of sciences Kunming 6502.4,china) (State Key Laboratory of Systematic and Evolutionary Botany Institute of Botany Chinese Academy of Sciences Beijing 100093 China) (Graduate University of Chinese academy of sciences Beijing 100049 China) (Southwestern china Germplasm Bank of Wild Species Kunming Institute of Botany Chinese Academy of Sciences Kunming 650204 China)

Clematis *** is revised in this paper based on the examination of a large number of herbarium specimens,extensive field observations,and morphometric *** taxonomic history and geographical distribution of the section are given,the relationships among the species are discussed,and the evolutionary trends of some characters in the section are *** staminodes of the plants in this section may have evolved from the outer stamens with petaloid filaments and gradually disappearing ***,they may have evolved in two different *** possibility is that the staminodes elongate and become lanceolate,as long as sepals,and their apices turn into *** other is that the staminodes are spathulate,but not elongating,as long as stamens,and their apices turn into retuse from obtuse and *** evolutionary trend of sepals may be from thin to thick in texture,and the veins from non-prominent to *** a result,five new series are established and nine species, two subspecies and nine varieties(including three new ranks) are recognized in this *** identification key is provided,and each taxon is described and *** sibirica and Clematis ochotensis are treated as subspecies of Clematis alpina due to their subtle differences and lack of,or few,overlapping *** fusijamana and Clematisfauriei are recognized as varieties of *** *** for the continuous variation of the velutinous strips on the sepal *** iliensis is treated as variety of *** *** for the continuous variation of leaf division *** variations in sepal color and basal caruncle size support degrading Clematis chiisanensis as a variety of Clematis *** North American *** may be primitive,whereas *** may be the most advanced taxon in this *** and *** are closely related to each ***,the systematic position of se

关键词： Clematis sect.Atragene Ranunculaceae taxonomic revision