North Atlantic climate impact on early late‐glacial climate oscillations in the south‐eastern Alps inferred from a multi‐proxy lake sediment record     

Roland Schmidt  Kaarina Weckström  Stefan Lauterbach  Richard Tessadri  Kerstin Huber 《第四纪科学杂志》2012,27(1):40-50

High‐resolution multi‐proxy analyses of a sediment core section from Lake Jeserzersee (Saissersee) in the piedmont lobe of the Würmian Drau glacier (Carinthia, Austria) reveal pronounced climatic oscillations during the early late glacial (ca. 18.5–16.0k cal a BP). Diatom‐inferred epilimnetic summer water temperatures show a close correspondence with temperature reconstructions from the adjacent Lake Längsee record and, on a hemispheric scale, with fluctuations of ice‐rafted debris in the North Atlantic. This suggests that North Atlantic climate triggered summer climate variability in the Alps during the early late glacial. The expansion of pine (mainly dwarf pine) between ca. 18.5 and 18.1k cal a BP indicates warming during the so‐called ‘Längsee oscillation’. The subsequent stepwise climate deterioration between ca. 18.1 and 17.6k cal a BP culminated in a tripartite cold period between ca. 17.6 and 16.9k cal a BP with diatom‐inferred summer water temperatures 8.5–10 °C below modern values and a shift from wet to dry conditions. This period probably coincides with a major Alpine glacier advance termed the Gschnitz stadial. A warmer interval between ca. 16.9 and 16.4k cal a BP separates this cold phase from a second, shorter and less pronounced cold phase between ca. 16.4 and 16.0k cal a BP, which is thought to correlate with the Clavadel/Senders glacier advance in the Alps. The following temperature increase, coupled with wet (probably snow‐rich) conditions, caused the expansion of birch during the transition period to the late glacial interstadial. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Identification of modal parameters of non‐classically damped linear structures under multi‐component earthquake loading     

M. Mahmoudabadi  M. Ghafory‐Ashtiany  M. Hosseini 《地震工程与结构动力学》2007,36(6):765-782

A method for parametric system identification of classically damped linear system in frequency domain is adopted and extended for non‐classically damped linear systems subjected up to six components of earthquake ground motions. This method is able to work in multi‐input/multi‐output (MIMO) case. The response of a two‐degree‐of‐freedom model with non‐classical damping, excited by one‐component earthquake ground motion, is simulated and used to verify the proposed system identification method in the single‐input/multi‐output case. Also, the records of a 10 storey real building during the Northridge earthquake is used to verify the proposed system identification method in the MIMO case. In this case, at first, a single‐input/multi‐output assumption is considered for the system and modal parameters are identified, then other components of earthquake ground motions are added, respectively, and the modal parameters are identified again. This procedure is repeated until all four components of earthquake ground motions which are measured at the base level of the building are included in the identification process. The results of identification of real building show that consideration of non‐classical damping and inclusion of the multi‐components effect of earthquake ground motions can improve the least‐squares match between the finite Fourier transforms of recorded and calculated acceleration responses. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

空间信息可视化的现状与趋势   总被引：10，自引：0，他引：10  

刘纪平  常燕卿等 《测绘学院学报》2002,19(3):207-210

对空间信息可视化的现状进行了较为细致的总结，分析了目前空间信息可视化存在的问题。在此基础上，讨论了空间信息可视化的完整概念，提出了空间信息可视化位置特征、交互性、多维性和可视化多样性的本质特征，概括了数据组织与调度、静态可视化、过程模拟与探索性分析等空间信息可视化基本过程。最后，提出未来空间信息可视化主要关键技术。  相似文献   

福建省物探找矿若干实例分析   总被引：1，自引：0，他引：1  

黄海清  许井明  黄春鹏 《福建地质》2002,21(1):27-34

物探作为一种地质勘察技术方法在国民经济各个领域，得到广泛的应用，物探方法和其它地质学科一样都存在着不足为奇的解释多解性。通过对福建省金，多金属，煤等矿产的地球物理勘察实例分析。认为要取得物探找矿效果应注意以下几点；（1）分析矿产的地质规律和特点；（2）掌握矿体与围岩之间物性差异的特征，直接找矿与间接找矿并举；（3）选择适合的物探方法，发挥各种方法的长处，（4）建立和利用矿床的地质-地球物理模型。圈出矿床（体）赋存的部位。  相似文献   

地下流体地震前兆多层次跟踪法短期预测在粤闽交界和珠江三角洲地区的应用     

叶秀薇 《华南地震》2001,21(2):42-47

利用粤闽交界地区、珠江三角洲地区连续10年左右的地下流体资料，研究利用多层次跟踪法进行地震短期预测的效果，结果表明，该法的粤闽交界及近海地区的应用效果较好，但在珠江三角洲及近海地区暂不宜应用。  相似文献   

极地记录冰川和达尔克冰川流速的遥感监测研究   总被引：1，自引：0，他引：1       下载免费PDF全文

孙家抦  霍东民  孙朝辉 《极地研究》2001,13(2):117-128

测定南极冰川的流速 ,对于研究南极冰雪物质平衡、南极环境变化及其对全球环境的影响有重大意义。本文论述了利用多时相卫星遥感影像监测冰川变化的原理和方法 ,通过对英格里特 .克里斯泰森海岸不同时期的遥感影像进行几何纠正和配准及叠加处理 ,测量和计算出极地记录冰川和达尔克冰川的平均流速 ,并对它们的变化特点进行了初步的分析和评价。  相似文献   

球面小波分析技术及在全球重力模型中的应用     

许惠平  刘万崧  R.H.N.Haagmans  A.J.Th.deBrnoue 《物探与化探》2001,25(1):8-13

在介绍球面小波理论的基础上,推导和比较了几种球面小波,分析了最新地球重力模型-EGM96,以此为依据,把球面小波多分辨分析用于计算全球自由空气异常及重力大地水准面,并对处理结果做出解释。  相似文献   

时间平均基流中准定常波的传播及多向折射     

郭品文  徐建军 《南京气象学院学报》1996,19(4):439-444

应用几何光学中的射线理论，直观地讨论了准定常波在时间平均基流中的传播，解释了定常 传播的纬向非均匀性。结果表明：折射指数平方可表示为基流绝对对基流流函数的微商，定常波的传播路径与折射指数平方的空间分布有着密切的关系。  相似文献   

新一代天气雷达     

刘力 《气象》1996,(8)

阐述了双偏振多普勒雷达的理论基础，以ＣＳＵ－ＣＨＩＬＬＳ波段双偏振多普勒天气雷达为例，介绍了双偏振多普勒雷达的系统结构和工作原理。并以雷达测量的数据处理和分析实例说明了双偏振多普勒雷达在气象学中的应用  相似文献   

应用最优化模型分析活断层与地震的关系   总被引：3，自引：0，他引：3       下载免费PDF全文

邵辉成  刘华峰  岳珠峰 《地震地质》2006,28(3):405-410

文中应用基于“多态”前兆模式及效能评价的最优效能单项模型参数选择方法,分析了3个地震带活断层(Qp3—Qh)与地震(M≥6)空间分布之间的关系。结果表明,河套地震带地震较集中分布在距断层20km的范围内,用其对6级以上地震进行地点预测有较高的准确性,R值达0.5,而对祁连山地震带30km范围内地震的发生地点进行预测,R值却仅为0.14  相似文献