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141.
Climate variability recorded by n-alkanes of paleolake sediment in Qaidam Basin on the northeast Tibetan Plateau in late MIS3 总被引:1,自引:0,他引:1
PU Yang ZHANG HuCai LEI GuoLiang CHANG FengQin YANG MingSheng ZHANG WenXiang LEI YanBin YANG LunQing & PANG YouZhi State Key Laboratory of Lake Science Environment Nanjing Institute of Geography Limnology Chinese Academy of Sciences Nanjing China Graduate University of Chinese Academy of Sciences Beijing Key Laboratory of Boyang Lake MOE School of Environmental Chemical Engineering Nanchang University Nanchang 《中国科学:地球科学(英文版)》2010,(6)
Here we combine n-alkanes preserved in a shell bar section from Qarhan paleolake, Qaidam Basin with the other sedimentary proxies to elucidate the lake evolution process during the period 39.7 to 17.5 14C ka BP (calibrated age ranges from 43.5 to 22.4 cal. ka BP). In different stages, the n-alkane homologues exhibited different distribution modes indicative of variations in the surrounding vegetation and the hydrologic condition of the lake. The n-alkanes proxies (CPIh, ACLh, Paq) have the same trends as th... 相似文献
142.
TRMM降水数据在横断山区的精度 总被引:5,自引:1,他引:4
利用相关系数法和散点斜率法对横断山区1998~2011年之间月尺度的TRMM 3B43降水数据精度进行了检验。研究表明,TRMM 3B43降水数据与实测数据相关性很强,但是比实测降水量偏大33.9%。在横断山北部大雪山以东地区和南部香格里-贡山-德钦一带三江并流区TRMM 3B43数据误差较大。各个季节TRMM 3B43降水与实测值误差的空间分布有较大区别,但是都表现为北部沿经向分布,南部沿纬向分布的趋势;横断山区高海拔地区气象站点稀少和复杂的下垫面环境是产生观测误差的主要原因。 相似文献
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Groundwater from karst subterranean streams is among the world’s most important sources of drinking water supplies, and the hydrochemical characteristics of karst water are impacted by both natural environment and people. Therefore, the study of hydrochemistry and its solutes’ sources is very important to ensure the normal function of life support systems. In this paper, thirty?five representative karst groundwater samples were collected from different aquifers (limestone and dolomite) and various land use types in Chongqing to trace the sources of solutes and relative hydrochemical processes. Hydrogeochemical types of karst groundwater in Chongqing were mainly of the Ca?HCO3 type or Ca (Mg)?HCO3 type. However, some hydrochemical types of karst groundwater were the K+Na+Ca?SO4 type (G25 site) or Ca?HCO3+SO4 type (G26 and G14 site), indicating that the hydrochemistry of these sites might be strongly influenced by anthropogenic activities or unique geological characteristics. The dissolved Sr concentrations of the studied groundwater ranged from 0.57 to 15.06 μmmol/L, and the 87Sr/86Sr varied from 0.70751 to 0.71627. The δ34S?SO42? fell into a range of ?6.8‰?21.5‰, with a mean value of 5.6‰. The variations of both 87Sr/86Sr and Sr values of the groundwater samples indicated that the Sr element was controlled by the weathering of limestone, dolomite and silicate rock. However, the figure of 87Sr/86Sr vs. Sr2+/[K++Na+] showed that the anthropogenic inputs also obviously contributed to the Sr contents. For tracing the detailed anthropogenic effects, we traced the sources of solutes collected karst groundwater samples in Chongqing according to the δ34S value of potential sulfate sources. The variations of both δ34S and 1/SO42? values of the groundwater samples indicated that the atmospheric acid deposition (AAD), dissolution of gypsum (GD), oxidation of sul?de mineral (OS) or anthropogenic inputs (SF: sewage or fertilizer) have contributed to solutes in karst groundwater. The influence of oxidation of sul?de mineral, atmospheric acid deposit and anthropogenic inputs to groundwater in Chongqing karst areas was much widespread. 相似文献
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为探讨城市轨道交通U型梁车桥系统的动力响应,采用线性化轮轨模型建立了31个自由度的轮轨式车辆动力学模型.模型考虑了新型算法的横竖向轨道不平顺,以重庆市轨道交通一号线工程中梁山以西高架区间所采用标准跨径为30m的单线小U结构为对象,采用自编程序对机车车辆过桥时的车桥耦合振动进行了分析,并通过计算与实测结果的对比分析对所建... 相似文献
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