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Climatic and environmental implications from n-alkanes in glacially eroded lake sediments in Tibetan Plateau:An example from Ximen Co

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Chinese Science Bulletin 2011年第14期56卷 1503-1510页

作者： PU Yang ZHANG HuCai WANG YongLi LEI GuoLiang NACE Trevor ZHANG ShuPing School of Remote Sensing Nanjing University of Information Science & Technology Nanjing 210044 China State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and Limnology Chinese Academy of Sciences Nanjing 210008. China Key Laboratory of Petroleum Resources Research Institute of Geology and Geophysics Chinese Academy of Sciences. Lanzhou 730000 China duke university. divisio. of earth and ocean sciences Durham. North Carolina 27708-0227. USA

Gas chromatography-mass spectrometry was used to identify a series of n-alkanes in the sediments of a typical glacially eroded lake in the eastern Tibetan *** comparing the distribution patterns of n-alkanes in lake sediments,surface soils and cow manure,it was shown that n-C 27-n-C 33 alkanes in the soil ecosystem of Ximen Co are derived from vascular plant species and that the distribution pattern of n-C 27-n-C 33 alkanes remains unchanged during the feeding and digestion processes of *** relative percentage of C 27,C 29 and C 31 n-alkanes decreased from the bottom to the top of the sediment core showing a trend of degradation of higher plants in the Ximen Co lake region during the formation of the 44 cm core.210 Pb dating,combined with pre-existing AMS 14 C dating results showed that the depositional core reflects climatic and environmental variations since about 900 years before *** n-alkane indexes (ACL 27-33,P aq,P wax) are comparable with regional temperature variation,especially recording the Little Ice Age event (LIA).This study highlights that n-alkanes are valid proxies for paleo-climate and paleo-environment reconstruction,despite the same distribution patterns in n-alkane molecular fossils derived from a typical glacially eroded lake.

关键词：湖泊沉积物青藏高原东部正构烷烃环境变化古气候侵蚀冰川合作

Climate &Sustainability Implications of Land Use Alterations in an Urbanizing Region: Raleigh-Durham, North Carolina

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Journal of Environmental Protection 2016年第7期7卷 1072-1088页

作者： E. M. B. Doran J. S. Golden divisio. of earth and ocean sciences Nicholas School of the Environment Duke University Durham USA

Urban climate is the most immediate manifestation of the warming global climate for the majority of people on earth. Nearly half of those people live in small to medium sized cities, an understudied scale in urban climate research. Widespread characterization would be useful to decision makers in planning and design for land use decisions. Using a multi-method approach, the mesoscale UHI in the study region is characterized and the secular trend over the last sixty years evaluated. Under isolated ideal conditions the findings indicate a UHI of 5.3℃ ± 0.97℃ to be present in the study area, the magnitude of which is growing over time.

关键词： Land Use Urban Heat Island Mesoscale Urban Climate Piedmont North Carolina

Climatic and environmental implications from n-alkanes in glacially eroded lake sediments in Tibetan Plateau:An example from Ximen Co

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Science Bulletin 2011年第14期56卷 1514-1521页

作者： NACE Trevor duke university Division of Earth and Ocean SciencesDurhamNorth Carolina 27708-0227USA

关键词： Tibetan Plateau glacially eroded lake Ximen Co lake sediment molecular fossil n-alkane climatic and environmental change

Impact of two different types of El Nino events on the Amazon climate and ecosystem productivity

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Journal of Plant Ecology 2011年第1期4卷 91-99页

作者： Wenhong Li Pengfei Zhang Jiansheng Ye Laifang Li Paul ABaker earth and ocean sciences Nicholas School of the EnvironmentDuke UniversityDurhamNC 27708USA College of Atmospheric sciences and Plateau Atmosphere and Environment Key Laboratory of Sichuan Province Chengdu University of Information TechnologyNo.24Block 1Xuefu RoadChengduSichuan610225P.R.China MOE Key Laboratory of Arid and Grassland Ecology School of Life ScienceLanzhou UniversityNo.222 Tianshui South RoadLanzhou730000P.R.China

Aims The Amazon basin plays an important role in the global carbon *** climate variability associated with El Nino can affect the Amazon ecosystem carbon *** recent years,studies have suggested that there are two different types of El Ninos:eastern-Pacific(EP)El Nino and central-Pacific(CP)El *** impacts of two types of El Nino on the Amazon climate and Amazon ecosystem are analyzed in the *** A composite method has been applied to highlight the common features for the EP-and CP-El Nino events using observational data,IPCC-AR4 model *** impacts of the two different types of El Nino on ecosystem carbon sequestration over the Amazon have been investigated using a process-based biogeochemical model,the Biome–BioGeochemical Cycles model(Biome–BGC).Important Findings Below-normal rainfall is observed year round in northern,central and eastern Amazonia during EP-El Nino *** CP-El Nino years,negative rainfall anomalies are observed in most of the Amazon during the austral summer wet season,while there is average or above-average precipitation in other ***-and CP-El Nino events produce strikingly different precipitation anomaly pattern in the tropical and subtropical Andes during the austral fall season:wetter conditions prevail during EP-El Nino years and drier conditions during CP-El Nino *** are above-average year round throughout tropical South America during EP-El Nino events,especially during austral *** CP-El Nino events,average or slightly above-average temperatures prevail in the tropics,but these temperatures are less extreme than EP year’s temperature except in austral *** precipitation and temperature anomalies influence ecosystem productivity and carbon sequestration throughout the *** the Biome–BGC model,we find that net ecosystem production(NEP)in the EP-El Nino years is below average,in agreement with most previous studies;such results indicate that the

关键词： EP-El Nino CP-El Nino Amazon climate Amazon ecosystem Amazon carbon sequestration

Improving forest burn severity estimations with partial least squares regression and orthogonal signal correction methods in Daxing'an Mountains,China

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Journal of Forestry Research 2021年第3期32卷 1157-1165页

作者： Cunyong Ju Tijiu Cai Wenhong Li Ge Sun Chengliang Lei Xueying Di Xiuling Man School of Forestry Northeast Forestry UniversityHarbin 150040People’s Republic of China Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education Northeast Forestry UniversityHarbin 150040People’s Republic of China earth and ocean sciences Nicholas SchoolDuke UniversityDurham 27708USA Eastern Forest Environmental Threat Assessment Center Southern Research StationUSDA Forest ServiceRaleigh 27606USA Endangered Species Import and Export Management Center State Forestry AdministrationBeijing 100714People’s Republic of China

Several indices and simple empirical models and ratios of single band from pre-and post-fire Landsat images have been developed to estimate and/or map burn ***,these models and indices are usually site-,time-and vegetation-dependent and their applications are *** Daxing'an Mountains range has the largest forested area in China and is prone to *** or not the existing models can effectively characterize the burn severity over a large region is *** this study,we used the orthogonal signal correction method based on partial least squares regression(PLSR)to select those variables that better interpret the variance of burn severity.A new index and other commonly used indices were used to construct a new,multivariate PLSR model which was compared with the popular single variable models,according to three assessment indices:relative root mean square error(RMSE%),relative bias(R E%)and Nash–Sutcliffe efficiency(NSE%).The results indicate that the multivariate PLSR model performed better than the other single variable models with higher NSE%(68.2%vs.67.8%)and less RE%(3.7%vs.-8.7%),while achieving almost the same R MSE%.We also discuss the spectral characteristics of the four selected variables for constructing the multivariate PLSR model and their correlation with the field burn severity *** new model developed from this study should help to better understand the patterns of forest burn severity and assist in vegetation restoration efforts in the region.

关键词： Satellite data Normalized burn ratio Variable selection Multiple regression

青藏高原冰蚀湖沉积物正构烷烃记录的气候和环境变化信息:以希门错为例

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科学通报 2011年第14期56卷 1132-1139页

作者：蒲阳张虎才王永莉雷国良 NACE Trevor 张淑萍南京信息工程大学遥感学院南京210044 中国科学院南京地理与湖泊研究所湖泊与环境国家重点实验室南京210008 中国科学院油气资源研究重点实验室兰州730000 divisio. of earth and ocean sciences Duke University

利用气相色谱一质谱联用仪从青藏高原东部典型冰蚀湖湖泊沉积物中检测出正构烷烃系列分子化石，将其与湖区表层土壤及牛粪中正构烷烃的分布特征进行对比，认为冰蚀湖湖泊沉积物中C27-C33正构烷烃主要来自流域内土壤生态系统中的高等植... 详细信息

利用气相色谱一质谱联用仪从青藏高原东部典型冰蚀湖湖泊沉积物中检测出正构烷烃系列分子化石，将其与湖区表层土壤及牛粪中正构烷烃的分布特征进行对比，认为冰蚀湖湖泊沉积物中C27-C33正构烷烃主要来自流域内土壤生态系统中的高等植物，且食草动物对高等植物的摄食消化过程并未显著改变C27-C33正构烷烃的分布特征．在0—44cm的湖泊沉积物岩芯中，陆生高等植被来源的正构烷烃相对含量从底部到顶部总体上呈现下降趋势，由此推测，湖区高等植被在0～44cm沉积时段内有逐渐退化的趋势．根据210Pb定年并结合已有的AMSH14^C年代，认为该沉积岩芯记录了希门错湖区过去近900a以来的气候和环境变化历史，其正构烷烃指标（ACL27-33，Paq以及Pwax）与区域温度记录具有一定的对应关系，特别是记录了相对寒冷的小冰期气候事件（LIA）．说明冰蚀湖湖泊沉积物中正构烷烃即使分布模式不变，其代用指标依然精细地记录了古气候、古环境变化信息．

关键词：青藏高原冰蚀湖希门错湖泊沉积物分子化石正构烷烃气候环境变化