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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 Sciences 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, Chinese Academy of Sciences, Lanzhou 73.000, China 2. college of {2.,{2.,{3., China Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou China college of geography Nanjing Normal University Nanjing 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 1956 to 2.01. 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.

A high-resolution late Pleistocene record of pollen vegetation and climate change from Jingning, NW China

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Science China Earth Sciences 2006年第2期49卷 154-162页

作者： LI Chunhai12. TANG Lingyu1, FENG Zhaodong3.4, ZHANG Hucai2. WANG Weiguo3.& AN Chenbang3.1. nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, nanjing 2.0008, China 2. Nanjng Institute of {2. and Limnology, Chinese Academy of Sciences, nanjing 2.0008, China 3. Environment and Resources college, Lanzhou university, Lanzhou 73.000, China 4. Beijing normal university, Beijing 100875, China nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing China Nanjng Institute of geography and Limnology Chinese Academy of Sciences Nanjing China Environment and Resources college Lanzhou University Lanzhou China Beijing normal university Beijing China

With the support of 18 AMS-14C data, a high-resolution pollen record from the Suancigou section at Jingning, Gansu Province was established. Our results showed that the vegetation ex-perienced a series of changes characterized by the alternative growth and decline of forest and steppe components during the period from 44.2.to 11 ka B.P. in the Jingning area. Over the period of 44―2. ka B.P. (MIS3., coniferous forests were flourishing, indicating a humid climate with the tem-perature being lower than that of the present. Since 2.0}ka B.P., the vegetation was dominated by steppe-desert steppe under a cold and dry condition, and entered the Last Glacial Maximum domi-nated by desert steppe. Several periods of the marked decrease in the arborous pollen content in Suancigou well corresponded to the North Atlantic Heinrich events, especially to Heinrich event 3. further supporting that the Heinrich events were well reflected by the pollen record in the Loess Pla-teau as well.

关键词： Western Loess Plateau, pollen record, climatic change, late Pleistocene.

Modal identification of system driven by lévy random excitation based on continuous time AR model

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Science China(Technological Sciences) 2009年第12期52卷 3649-3653页

作者： DU XiuLi 1,2.&WANG FengQuan 1 1 college of Civil Engineering,Southeast university,{2. 2.0096,China 2.School of Mathematical Sciences,{2. normal university,{2. 2.0097,China college of Civil Engineering Southeast University Nanjing China School of Mathematical Sciences Nanjing Normal University Nanjing China

Based on the continuous time AR model,this paper presents a new time-domain modal identification method of LTI system driven by the uniformly modulated lévy random *** structural dynamic equation is first transformed into the observation equation and the state equation(namely,stochastic differential equation).Based on the property of the strong solution of the stochastic differential equation,the uniformly modulated function is identified *** by virtue of the Girsanov theorem,we present the exact maximum likelihood estimators of ***,the modal parameters are identified by eigen *** results show that the method not only has high precision and robustness but also has very high computing efficiency.

关键词： modal identification uniformly modulated function CAR model lévy process exact maximum likelihood estimator

Origin of the Red Earth sequence on the northeastern Tibetan Plateau and its implications for regional aridity since the middle Miocene

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Science China Earth Sciences 2006年第5期49卷 505-517页

作者： WANG Xianyan1,7, LU Huayu1,2. JI Junfeg3. WANG Xiaoyong1,7, ZHAO Jingbo4, HUANG Baochun5 & LI Zhen6 1. SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710075, China 2. Department of Urban and Resources Sciences, nanjing {2., nanjing 2.0093. China 3. Department of Earth Sciences, nanjing {2., nanjing 2.0093. China 4. Department of geography, Shaanxi normal {2., Xi’an 710062. China 5. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 10002., China 6 Department of geography, Qinghai normal {2., Xining 810008, China 7. Graduate School of the Chinese Academy of Sciences, Beijing 10003., China SKLLQG Institute of Earth Environment Chinese Academy of Sciences Xi’an China Graduate School of the Chinese Academy of Sciences Beijing China Department of Urban and Resources Sciences Nanjing University Nanjing China Department of Earth Sciences Nanjing University Nanjing China Department of geography Shaanxi Normal University Xi’an China Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China Department of geography Qinghai Normal University Xining China

The Red Earth deposit around Xining, northeastern Tibetan Plateau, has beenstudied in terms of soil micro-structure, grain-size distribution, major- and trace-elementchemistry and magne-tostratigraphy. Field investigations indicate that the Red Earth sequenceconsists of 2. visually definable yellow-brown and weakly-developed soils interbedded with reddishstrongly-developed soils, and has a similar structure to the aeolian Red Clay deposit on the ChineseLoess Plateau. Grain-size analysis shows that the Red Earth deposit is very fine-grained with anegligible sand fraction ( > 63.μm). Thin-section observations under light microscopy show that thedeposit has a clayey texture and the coarse fraction ( > 10 μm) mainly consists of quartz,feldspar and micas. Pyroxene and hornblende were also observed. This mineralogical composition ofthe coarse fraction is similar to that of the Quaternary loess. In addition, all of the mineralgrains are semi angular semi-angular and are generally finer than 63.μm. There is a good agreementbetween the major and minor trace element chemistry of loess-soil units and the Red Earth *** REE distributions of the loess-soil and the Red Earth deposit are similar in shape, withenriched LREE and fairly flat HREE profiles and a clear negative Eu anomaly. The geochemicalcharacteristics of the Red Earth deposit are also identical to those of upper continental crust,thus indicating a wind-blown origin. Magnetostratigraphic investigation shows that onset of the RedEarth deposition predates 11.4 Ma BP (13.6 Ma at a nearby site). The distribution of the reportedMiocene aeolian loess at Qin''an of the Loess Plateau is still unknown. Our results indicate thatthis aeolian deposit had extended to the northeastern Tibetan Plateau by at least the middleMiocene. The similarity of the element geochemistry between the Red Earth deposit and the overlyingloess shows that they may have similar sources and dynamic transport system, and may indicate thatthe

关键词： Red Earth deposit, Northeastern Tibetan Plateau, aeolian deposit, aridity of Asia, the middle Miocene.

Miocene Bahean stratigraphy in the Longzhong Basin, northern central China and its implications in environmental change

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Science China Earth Sciences 2006年第12期49卷 1270-1279页

作者： LI Jijun1,2. ZHANG Jun1, SONG Chunhui1, ZHAO Zhijun2. ZHANG Yong1, WANG Xiuxi 1, ZHANG Jianming1 & CUI Qiaoyu1 1. Key Laboratory of Western China’s Environmental Systems (Ministry of Education) & college of Earth and Environment Sciences, Lanzhou university, Lanzhou 7{2.000, China 2. Jiangsu Key Laboratory of Environmental Change and Ecological Construction & college of {{2., nanjing normal university, nanjing 2.0097, China Key Laboratory of Western China’s Environmental Systems (Ministry of Education) & college of Earth and Environment Sciences Lanzhou University Lanzhou China Jiangsu Key Laboratory of Environmental Change and Ecological Construction & college of geography Nanjing Normal University Nanjing China

Fossil mammal-riched Neogene strata are widely distributed in the southeast corner of the huge Longzhong Basin at Tianshui, Gansu Province, northern central China. Hipparion weihoense, a typical member of late Middle Miocene Bahean stage, was recently excavated at Yaodian along a well-exposed outcrop. Owing to the importance of the Bahean stage in the mammalian evolution and its potential for environmental change, we suggested a name of Yaodian Formation for the stratigra- phy, which is correlated to the Bahe Formation at Lantian, Shaanxi. High resolution paleomagnetic dating of the section shows that the Yaodian Formation covers the period between 11.67 Ma and 7.43.Ma, with the site bearing Hipparion weihoense being estimated at about 10.54―10.3. Ma, providing first magnetostratigraphic chronology for the Bahean Stage. The Yaodian Formation consists of fluvial channel deposits (11.67―10.40 Ma) at the bottom, floodplain deposits in the middle (10.40―9.2.0}Ma) and shallow lake sediments at the top (9.2.0}7.43.Ma). This upward fining sequence suggests that the relief in nearby mountain ranges such as West Qinling to the south and Huajia Ling to the north was greatly reduced after long-term denudation, fluvial transport capacity was low, and finally the drainage system was disintegrated, replaced with broad-shallow lakes in which only fine sediments like mud and marlite were deposited, indicating an old stage of development of a planation surface. A remarkable shift in ecology and climatic environment was found at 7.4―7.7 Ma when paleoclimate changed from early warm humid to late dry as indicated by sedimentary facies changed from early shallow lake sequence to late eolian red clays and a former coniferous-deciduous mixed forest was replaced by grassland, leading to great growth of Hipparion Fauna of Baodean stage in the region. Therefore, it is estimated that the present high relief of Qinling and drainage pattern did not come into being until Late Pliocene in response

关键词： Bahean stage,magnetostratigraphy,Yaodian Formation,Neogene,Longzhong Basin.

Landscape structure and land uese on county level in northeastern Yunnan Province of China——a case study of Huize County

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Journal of Environmental Sciences 2000年第3期12卷 355-360页

作者： WANG Jin\|liang, NI Shao\|xiang (college of Geographical Science, nanjing normal university,{2., China) 南京师范大学江苏南京 2 1 0 0 97

Taking Huize County as an example, the paper analyzed the landscape structure(landscape element structure, landscape type structure, landscape spatial structure, landscape succession structure) and the relations between landscape structure and land use. It was pointed out that the agriculture should be developed in harmony with the landscape structure in the study area.

关键词： landscape structure land use agriculture Yunnan Province China

Nonlinear ergodic theorem for semitopological semigroups of non-Lipschitzian mappings in Banach spaces

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Chinese Science Bulletin 1997年第1期42卷 8-11页

作者： LI Gang and MA Jipu1. Department of Mathematics, Yangzhou normal college, Yangzhou 2.5002. China 2. Department of Mathematics, {2. {3., {2. 2.0093. China Department of Mathematics Yangzhou Normal College Yangzhou China Department of Mathematics Nanjing University Nanjing China

LET G be a semitopological semigroup, i. e. G is a semigroup with a Hausdorff topology such that for each s∈G the mapping s|→s·t and s|→t·s from G to G are continuous. G is called right reversible if any two closed left ideals of G have non-void intersection. In this case, (G,≤) is a directed system when the binary relation '≤' on G is defined by a≤b if and only if Let E be the uniformly convex Banach space

关键词： nonlinear semigroup ergodic theorem non-Lipschitzian mapping.

High resolution stalagmite δ18O records over the past 1000 years from Dongge Cave in Guizhou

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Science Bulletin 2005年第10期50卷 1003-1008页

作者： HE Yaoqi1, WANG Yongjin1, KONG Xinggong1 & CHENG Hai2. 1. college of geography Science,{2., {3. 2.0097, China 2. Department of Geology and Geophysics, Minnesota university, Mineapolis MN 55455, USA college of geography Science Nanjing Normal University Nanjing China Department of Geology and Geophysics Minnesota University Mineapolis USA

Based on MC-ICP-MS U-series dating and stable O-isotope analysis results, a 4―5 years resolution monsoon record over the past 1000 years has been estab- lished for two stalagmites from Dongge Cave, Guizhou. The high resolution oxygen isotope record serves as a proxy for variations in rainfall of Asian southwest monsoon over the Yunnan-Guizhou Plateau. A close relation of the δ 18O record with the ?14C record from tree rings largely reflects impact of centennial-scale solar activity on the monsoon climate changes. The conspicuous decrease in the δ 18O value at AD 172. indicates an abrupt increase in monsoon rainfall, sug- gesting that an atmospheric-oceanic couple over the tropical Indian Ocean plays an important role in rapid increase of the Northern Hemisphere temperature over the last century.

关键词： cave stalagmite oxygen isotope southwest monsoon solar activity Guizhou.

Predicting bioconcentration factor values of organic pollutants based on medv descriptors derived QSARs

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Science China Chemistry 2007年第5期50卷 587-592页

作者： CUI ShiHai1,2. YANG Jing1, LIU ShuShen2.3.& WANG LianSheng2.1 college of Chemistry and Environment,{2.,{2., China 2.State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, {3. university, {3. 2.0093. China 3.Key Laboratory of Yangtze Aquatic Environment, Ministry of Education, college of Environmental Science and Engineering, Tongji university, Shanghai 2.0092. China college of Chemistry and Environment Nanjing Normal University Nanjing China State Key Laboratory of Pollution Control and Resources Reuse School of the Environment Nanjing University Nanjing China Key Laboratory of Yangtze Aquatic Environment Ministry of Education College of Environmental Science and Engineering Tongji University Shanghai China

The molecular electronegativity-distance vector (MEDV) is employed todescribe the chemical structure of organic *** linear relationships between themolecular descriptors and BCF values are developed by best subset regression and partial leastsquare regression *** main structural factors influencing the bioactivities are -CH2.-X,-Cnot 2.and q2.(LOO) present good estimation ability and stabilityof *** prediction power for external samples is validated by the model developed from thetraining set.

关键词： POPs, BCF, MEDV, QSAR