云南5月雨量的多尺度变化及与其相联系的大气环流异常   总被引：1，自引：1，他引：1  

万云霞  程建刚  陈新梅  孙绩华  严华生 《气象科学》2007,27(5):543-548

本文运用小波分析和功率谱分析方法对云南5月雨量的多尺度时间演变特征进行了分析,结果表明,云南5月雨量具有明显的年际和年代际变化特征。对与这两种时间尺度相关联的大气环流异常进行了分析,发现两者具有显著的差异。云南5月雨量的年际变化与冰岛低压、欧洲槽、南亚高压、中西太平洋ITCZ以及孟湾附近的低压系统的变化有着密切的关系,云南5月雨量的年代际-气候态变化与热带各系统的强度、乌山脊、阿留申低压关系密切。  相似文献   

A holistic approach to aligning geospatial data with multidimensional similarity measuring     

Li Yu  Peiyuan Qiu  Xiliang Liu  Bo Wan 《International Journal of Digital Earth》2018,11(8):845-862

Semantically aligning the heterogeneous geospatial datasets (GDs) produced by different organizations demands efficient similarity matching methods. However, the strategies employed to align the schema (concept and property) and instances are usually not reusable, and the effects of unbalanced information tend to be neglected in GD alignment. To solve this problem, a holistic approach is presented in this paper to integrally align the geospatial entities (concepts, properties and instances) simultaneously. Spatial, lexical, structural and extensional similarity metrics are designed and automatically aggregated by means of approval voting. The presented approach is validated with real geographical semantic webs, Geonames and OpenStreetMap. Compared with the well-known extensional-based aligning system, the presented approach not only considers more information involved in GD alignment, but also avoids the artificial parameter setting in metric aggregation. It reduces the dependency on specific information, and makes the alignment more robust under the unbalanced distribution of various information.  相似文献   

An elastoplastic description of frictional destructuration in natural clays and shales     

Morteza Mohamadi  Richard Wan  Zhifu Shen 《Acta Geotechnica》2018,13(4):911-924

The existence of structuration in natural clays and shales is believed to change their stiffness, yielding, dilatancy and strength characteristics. These constitutive features are widely known to ultimately reunite with those of the reconstituted parent soil upon large straining. However, some experimental results show that such reunification may not occur in isotropic/one-dimensional compression, especially with regard to the critical state friction angle. This peculiar phenomenon has been barely addressed in constitutive models for natural geomaterials. Hence, the present study aims at introducing a structure-dependent critical state friction angle within the subloading yield framework. A new internal variable is introduced in the model of Nakai et al. (Soils Found 51(6):1149–1168, 2011) to capture subtle irreversible degradation of the structured critical state line which also serves as the threshold between contractive and dilatant volume changes. Additionally, a new evolution rule for the proposed destructuration factor is developed by considering important microstructural information revealed by discrete element method simulations. The proposed new modifications not only enhance the model capabilities in predicting bonding effects, but also enrich the classical stress-dilatancy equation by rendering it a function of void ratio, mean stress and the microstructural state. Model simulations of laboratory experimental tests on the Colorado shale as well as Bacinetto clay are presented in order to illustrate the improved predictive capabilities of the new model.  相似文献   

隧道洞口段位于滑坡体上的处治方法     

唐连权  万小乐 《江苏地质》2018,42(2):328-333

隧道洞口段选址在滑坡体上的现象较为常见。以玉园隧道为工程实例,阐述了隧道洞口段滑坡地质灾害的成因及防治方法,通过数值计算针对性地提出该滑坡的应急处治措施。计算结果表明现有变形体为牵引式变形,卸载方案不利于其稳定,进而提出抗滑桩+降水、抗滑桩+旋喷桩2种方案,探讨2种处治方案的比较与选择,为类似的工程提供经验。  相似文献   

羌塘盆地南坳陷古油藏带中侏罗统布曲组白云岩元素地球化学特征及意义          下载免费PDF全文

万友利  王剑  付修根  王东 《沉积与特提斯地质》2018,38(2):23-35

在前期详细岩石学分类的基础上,研究南羌塘坳陷布曲组碳酸盐岩微量元素地球化学特征及意义。结果表明:(1)布曲组碳酸盐岩具有较低的微量元素含量,与班公湖-怒江洋盆海水快速入侵及炎热、半潮湿-半干旱条件下缺少地表径流补偿陆源物质有关;(2)Na元素和K元素指示布曲组保留先驱灰岩原始组构的白云岩和不保留先驱灰岩原始组构的晶粒白云岩的初始流体为同期蒸发海水,岩石中Sr元素的含量受方解石和白云石的相对含量控制;(3)经历不彻底白云石化作用的过渡性岩类(RD5-1)是在中-深埋藏阶段中-晚期不彻底交代先驱灰岩形成,细-中晶、自形-半自形白云石充填物由微-粉晶白云岩在浅埋藏阶段末期重结晶形成;(4)鞍形白云石的形成有外来高温流体参与,流体成因具大气淡水参与、流经碎屑岩地层深循环流体特征。新生代(78~64Ma)构造热事件是形成高温流体的热源,部分基质白云岩受到构造热事件的高温改造。  相似文献   

东昆仑虎头崖多金属矿田成矿地质特征及找矿标志研究     

屈翠侠  刘渭  杨兴科  何虎军  江万 《西北地质》2015,(1):117-126

虎头崖矿田属于近年来新确立的青海省三轮成矿远景区划及找矿靶区预测中的青海省都兰三级成矿带(Ⅲ11)的西段部分,是青海省十分重要的铜多金属成矿区带。由于该铜铅锌多金属矿床的成矿作用复杂,对成矿控制因素的研究缺少系统性,导致对于矿区的成矿模型的建立仍然不是很明确,其已成为制约找矿突破的瓶颈。通过近年来的研究成果和笔者野外及室内综合分析,总结了与成矿关系密切的容矿地层、控矿构造、岩相分布和侵入体特征,初步建立了该矿田区主要成矿-控矿因素的空间关系,并提出了地质找矿标志。这些认识对进一步分析该区矿床特征、性质、成矿关系和构造背景,以及进一步找矿都将有重要理论和实践指导意义。  相似文献   

A new method for parameter estimation in nonlinear dynamical equations     

Liu Wang  Wen-Ping He  Le-Jian Liao  Shi-Quan Wan  Tao He 《Theoretical and Applied Climatology》2015,119(1-2):193-202

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高原夏季风与南海夏季风关系及其影响     

李俊乐  范广洲  周定文  丑纯磊  冯琬 《气象科学》2015,35(5):565-573

利用1983-2012年NCEP/NCAR、NCEP/DOE、ECMWF再分析月平均资料,及中国160站月平均气温和降水量资料,利用统计学方法从大气环流、降水及温度等方面对高原夏季风与南海夏季风的关系进行了探讨。结果表明:高原夏季风与南海夏季风呈负相关关系,且大气环流及对流活动存在显著性差异。高原夏季风偏强(弱)同时南海夏季风偏弱(强)时,同期中国大部分地区的500hPa高度场偏低(高),南海地区500hPa高度场偏高(低);欧亚大陆低纬地区大部为偏东(西)风,南海地区处于反气旋(气旋)环流中。青藏高原主体地区上升运动较弱(强),南海中心区域上升运动均较弱(强),长江中下游地区降水增加(减少),华南降水减少(增加)。中国大部分地区气温较低(高),华南地区气温较高(低)。  相似文献   

原子荧光测试淮南二叠纪煤中锗的不确定度评定     

徐辉  万亚丽  黄丽莉  王文强 《中国煤炭地质》2021,(2)

利用原子荧光测试了淮南二叠纪煤中锗的含量,并对测试结果进行了多次重复测量,分别考察了样品称重、前处理过程、定容体积、工作曲线拟合、重复性测量等影响因素引入的不确定度,同时对各不确定度分量进行了评估。结果表明,原子荧光测试煤中锗的不确定度主要由样品前处理过程、样品重复性试验和拟合工作曲线所产生,实验样品为淮南石河子组煤中锗的含量为2.95mg/kg,其扩展不确定度为0.536mg/kg,评定过程准确可靠,测量结果的可信程度高。  相似文献   

Impacts of Indian summer monsoon and stratospheric intrusion on air pollutants in the inland Tibetan Plateau     

Xiufeng Yin  Shichang Kang  Benjamin de Foy  Dipesh Rupakheti  Maheswar Rupakheti  Zhiyuan Cong  Xin Wan  Guoshuai Zhang  Qianggong Zhang 《地学前缘(英文版)》2021,12(6):294-298

Air pollutants can be transported to the pristine regions such as the Tibetan Plateau,by monsoon and stratospheric intrusion.The Tibetan Plateau region has limited local anthropogenic emissions,while this region is influenced strongly by transport of heavy emissions mainly from South Asia.We conducted a comprehensive study on various air pollutants(PM2.5,total gaseous mercury,and surface ozone)at Nam Co Station in the inland Tibetan Plateau.Monthly mean PM2.5 concentration at Nam Co peaked in April before monsoon season,and decreased during the whole monsoon season(June-September).Monthly mean total gaseous mercury concentrations at Nam Co peaked in July and were in high levels during monsoon season.The Indian summer monsoon acted as a facilitator for transporting gaseous pol-lutants(total gaseous mercury)but a suppressor for particulate pollutants(PM2.5)during the monsoon season.Different from both PM2.5 and total gaseous mercury variabilities,surface ozone concentrations at Nam Co are primarily attributed to stratospheric intrusion of ozone and peaked in May.The effects of the Indian summer monsoon and stratospheric intrusion on air pollutants in the inland Tibetan Plateau are complex and require further studies.  相似文献