过去2000年冷暖变化的基本特征与主要暖期   总被引：1，自引：0，他引：1  

葛全胜  刘健  方修琦  杨保  郝志新  邵雪梅  郑景云 《地理学报》2013,68(5):579-592

根据近年国内外相关研究结果,分析了北半球与中国过去2000 年冷暖变化的阶段性,辨识了百年尺度暖期的起讫年代及其与20 世纪温暖程度的差别。结果表明:(1) 最近新建的多数北半球温度变化序列显示公元1-270 年温暖;271-840 年冷暖相间,但总体偏冷;841-1290年温暖;1291-1910 年寒冷;1911 年以后再次转为温暖;这些冷暖阶段虽分别与Lamb 指出的罗马暖期(约公元前1 世纪-4 世纪中期)、黑暗时代冷期(约4 世纪末-10 世纪前期)、中世纪暖期(约10 世纪中期-13 世纪末)、小冰期(约15-19 世纪) 以及20 世纪增暖大致对应,但各阶段的起讫时间与Lamb确定的时段存在一定差别。(2) 尽管过去2000 年冷暖变化过程及其变幅大小在中国境内各个区域间并不完全一致,但从全国平均看,中国与北半球百年尺度的冷暖波动阶段基本一致,仅起讫年代存在一定差异;其中公元1-200 年、551-760 年、941-1300 年及20世纪气候相对温暖,其他时段则相对寒冷。(3) 多数序列显示中世纪期间北半球的温暖程度至少与20 世纪相当。中国941-1300 年间的最暖百年和最暖30 年(暖峰) 的温度也略高于20 世纪,551-760 年间的最暖百年与20 世纪基本相当,但1-200 年间最暖百年的温暖程度则较20 世纪略低。  相似文献   

一种黄土高边坡设计的新方法   总被引：5，自引：2，他引：3  

叶万军  王东耀  折学森  倪万魁  陈志新  付兵先 《工程地质学报》2005,13(3):415-418

根据黄土高边坡破坏面的实际特征,假定最危险滑动面为抛物线型,对高边坡进行可靠度分析,应用数学原理,建立了黄土高边坡的设计模型,并对铜黄一级公路黄土高边坡进行分析验证,结果表明,该方法计算的结果与实际较接近。该方法物理意义明确,易操作,可供设计人员参考。  相似文献   

Size-based analysis for the state and heterogeneity of pelagic ecosystems in the northern South China Sea     

Linbin Zhou  Yehui Tan  Liangmin Huang  Xiping Lian  Dajun Qiu  Zhixin Ke 《Journal of Oceanography》2013,69(4):379-393

Analyzing and evaluating the state and heterogeneity of ecosystems are required for ecosystem-based management. The abundance size spectrum is a promising approach for evaluating pelagic ecosystems. To analyze the heterogeneity of pelagic ecosystems in the northern South China Sea (NSCS) in summer, a simplified abundance size spectrum (SASS) was proposed. Picophytoplankton (0.2–2 μm), microphytoplankton (10–160 μm), mesozooplankton (160–2000 μm), and macrozooplankton (505–8,000 μm) were sampled in the NSCS in August 2007, and used to build the SASS. On the basis of the SASS parameters, spatial heterogeneity in pelagic ecosystems was detected, and the study waters were distinctly categorized into the river plume or upwelling-affected area and its adjacent coastal area, the deepwater area, area near the Luzon Strait, and the offshore shelf area. Contrasts of SASS parameters between the eastern and western pelagic ecosystems out of the Pear River estuary demonstrate the fast ecosystem response to the spreading of the Pearl River plume. These results indicate that the SASS could be a good indicator for the state of pelagic ecosystems in the NSCS. In addition, the SASS approach is easily available and labor- and time-saving, thus the SASS could be a useful tool for monitoring and evaluating the state of pelagic ecosystems and their responses to perturbations.  相似文献   

Geothermic activity and seismotectonics in the altitude of the Tibetan plateau     

Jiren Xu  Zhixin Zhao Institute of Geology  Chinese Academy of Geological Sciences  Beijing  China 《地震学报(英文版)》2009,(6):651-658

In the present analysis on the relationships among the depth of lithosphere brittle fracture,seismotectonics and geothermal anomalous active in Tibetan plateau were investigated using the seismic dada from ISC and Chinese seismic net and geothermal data.The results suggest that the region of anomalously geothermal activity almost coincides with that of the normal faulting type earthquake.The geothermal anomaly activity region coincides spatially with that of the events deeper than 60 km as well as.The norma...  相似文献   

大亚湾表层沉积物重金属元素形态特征、控制因素及风险评价分析     

曹玲珑  王建华  黄楚光  倪志鑫  金钢雄  瓦西拉里  陈慧娴 《吉林大学学报(地球科学版)》2014,44(6):1988

为了解大亚湾表层沉积物中重金属的污染状况,对大亚湾海域23个点位表层沉积物中7种重金属元素（Cr、Ni、Cu、Pb、Zn、Cd、As）的质量分数、形态特征、来源控制因素以及潜在生态风险进行了研究。采用优化BCR提取法分析重金属元素赋存形态,并依据各种重金属元素的形态特征与沉积物基质属性进行了相关因子分析,了解其分布的控制因素。结果表明：大亚湾沉积物重金属元素呈现环带状分布特征,从岸向湾内逐渐减小;重金属元素质量分数的高值区主要分布于大鹏澳、哑铃湾及范和港附近;重金属元素赋存形态中Cr、Ni、Cu、Zn、As主要以残渣态存在,Pb主要以可还原态存在,Cd主要以酸提取态存在;7种重金属元素各自非残渣态所占比率从大到小为Pb(78.83%)、Cd(78.65%)、Cu(48.54%)、Zn(48.10%)、Ni(38.31%)、Cr(28.43%)、As(27.76%),即Pb最高,As最低,表明Pb的迁移性最强;通过因子分析,大亚湾重金属主要为沿岸自然风化产物的输入,其次为工业废水及养殖污水。运用酸提取态风险评估法对重金属元素潜在生态风险进行评价,发现研究区所选重金属元素综合风险评价Cd为高风险,其余重金属为中-低风险等级。  相似文献   

Variations in the starting date of the pre-summer rainy season in South China, 1736–2010     

Lingling Ding  Quansheng Ge  Jingyun Zheng  Zhixin Hao 《地理学报(英文版)》2014,24(5):845-857

The starting dates of the pre-summer rainy season during historical times （1736- 1911） in Fuzhou and Guangzhou of South China, were determined and reconstructed on the basis of historical documents in the Yu-Xue-Fen-Cun archive, together with observed features of precipitation during the pre-summer rainy season. In addition, starting dates of the pre-summer rainy season from 1953 in Fuzhou and from 1952 in Guangzhou were reconstructed for the instrumental period. These data allowed for analyses of inter-annual and inter-decadal changes in the starting dates of the pre-summer rainy season in South China over the past 300 years. Results show that the mean starting date of the pre-summer rainy season in South China was the first pentad of May; in addition, periodicities in the starting dates of 2-3 years, 10 years, and 40 years were detected during the period 1736-1911, and of 2-3 years, 10 years, and 22 years during the instrumental period. From 1736 to 1911, the earliest starting dates at Fuzhou and Guangzhou both occurred at the fourth pentad of April, while the latest starting dates were at the sixth pentad of May in Fuzhou and the first pentad of June in Guangzhou. During the instrumental period, the earliest and latest starting dates were at the fourth pentad of April and the first pentad of June, respectively, in both Fuzhou during 1953-2010 and Guangzhou during 1952-2010. The maximum difference between neighboring decades during 1736-1911 was 2.2 and 1.6 pentads in Fuzhou and Guangzhou, respectively, and during the instrumental period it was 2.5 and 2.4 pentads in Fuzhou and Guangzhou, respectively.  相似文献   

非洲地区盆地演化与油气分布   总被引：2，自引：0，他引：2  

张光亚  余朝华  陈忠民  张荻萩  温志新  黄彤飞  王彦奇  刘小兵  马锋  赵健 《地学前缘》2018,25(2):1-14

非洲地区盆地整体勘探程度较低,待发现资源量大,是当前油气勘探开发的热点地区之一。非洲板块在显生宙主要经历了冈瓦纳大陆形成、整体运动和裂解3个构造演化阶段,形成多种不同类型的盆地。通过板块构造演化和原型盆地研究及石油地质综合分析,明确了不同类型盆地的构造特征与油气富集规律。北非克拉通边缘盆地形成于古生代早期,受海西运动影响,油气主要富集在挤压背景下形成的大型穹隆构造之中,以古生界含油气系统为主;北非边缘裂谷盆地海西运动之后普遍经历了裂谷和沉降,裂谷期各盆地沉降幅度和沉降中心的差异导致了油气成藏模式和资源潜力的差异;东、西非被动陆缘盆地形成于中生代潘吉亚大陆的解体、大西洋和印度洋张裂的过程中,西非被动陆缘盆地普遍发育含盐地层,形成盐上和盐下两套含油气系统,东非被动陆缘盆地结构差异较大,油气分布主要受盆地结构控制;中西非裂谷系是经历早白垩世、晚白垩世和古近纪3期裂谷作用而形成的陆内裂谷盆地,受晚白垩世非洲板块与欧亚板块碰撞的影响,近东西向展布盆地抬升剧烈,油气主要富集在下白垩统,北西南东向盆地受影响较弱,油气主要富集在上白垩统和古近系之中;新生代东非裂谷系盆地和红海盆地形成时间相对较晚,以新生界含油气系统为主,新生代三角洲盆地中油气分布主要受三角洲砂(扇)体展布和盆地结构所控制。  相似文献   

中尺度涡影响下的南海西部活性铝分布   总被引：1，自引：0，他引：1  

刘甲星  周林滨  谭烨辉  王琼  胡子峰  李佳俊  姜歆  柯志新 《海洋学报(英文版)》2017,36(6):95-103

To understand the distribution of aluminum(Al) under the influence of mesocale eddies in the western South China Sea(SCS), sea level anomaly, geostrophic current, environmental parameters and reactive Al were investigated in the western SCS in August 2013. The highest reactive Al concentration((180±64) nmol/L) was observed in the surface waters, indicating a substantial atmospheric input. Vertically, the reactive Al decreased from the surface high concentration to the subsurface minima at the depth of chlorophyll a(Chl a) maxima and then increased again with depth at most of the stations. The average concentration of reactive Al in the upper 100 m water column was significantly lower in the cyclonic eddy((137±6) nmol/L) as compared with that in the noneddy waters((180±21) nmol/L). By contrast, the average concentrations of Chl a and silicate in the upper 100 m water column were higher in the cyclonic eddy and lower in the anticyclonic eddy. There was a significant negative correlation between the average concentrations of reactive Al and Chl a in the upper 100 m water column. The vertical distribution of reactive Al and the negative correlation between reactive Al and Chl a both suggest that the reactive Al in the upper water column was significantly influenced by biological removal processes. Our results indicate that mesoscale eddies could regulate the distribution of reactive Al by influencing the primary production and phytoplankton community structure in the western SCS.  相似文献   

温度影响下膨胀土强度的试验研究     

翟聚云  卫国祥  郝晓  马明江  言志信 《冰川冻土》2017,39(3):629-633

通过对河南平顶山膨胀土温度影响下的抗剪强度试验,揭示了膨胀土的强度随温度、含水量、干密度、压力等参数变化的规律。结果表明：相同压力作用下膨胀土强度随含水量不同有较显著的变化,随含水量增加而减小。但当含水量增加到一定程度,强度不再随压力而变化,即内摩擦角为0。当含水量较高时,温度影响显著,相同压力、含水量和干密度情况下,液相为全液体时,随温度的升高抗剪强度增大;当液相有部分结冰时,其规律与干密度的大小有关。含水量较小时,压力较小情况下,温度对抗剪强度影响不明显。  相似文献   

鲁西徂徕山地区傲来山序列二长花岗岩锆石LA-ICP-MS U-Pb定年及其地质意义          下载免费PDF全文

靳立杰  赵体群  高继雷  刘伟  于松  杨帆  韩智昕 《山东国土资源》2017,33(12)

出露于鲁西徂徕山地区的傲来山序列二长花岗岩是鲁西新太古代岩浆作用的重要记录,在野外地质工作的基础上,通过对其进行锆石LA-ICP-MS U-Pb同位素年代学研究,得到了二长花岗岩的形成时代,并对鲁西地区新太古代的岩浆活动进行了讨论。研究得到,谐和度90%的锆石中存在岩浆锆石~2 520Ma和继承性岩浆锆石2611Ma~2 766Ma两个年龄区间。岩浆锆石的加权平均年龄为(2 525±18)Ma,认为这一年龄代表了二长花岗岩的形成年龄。2 611Ma~2 766Ma继承性岩浆锆石的存在反映了鲁西地区至少经历了2次壳源物质的重熔和加入。  相似文献