Mesospheric bore events in the equatorial middle atmosphere     

J. Fechine  A.F. Medeiros  R.A. Buriti  H. Takahashi  D. Gobbi 《Journal of Atmospheric and Solar》2005,67(17-18):1774

An all-sky CCD imager designed to measure wave structure of the OH, O₂b(0,1) and OI557.7 nm airglow emission layers in the mesosphere and lower thermosphere (MLT) region has been operated near the equatorial region at São João do Cariri (Cariri), Brazil, (7.5°S, 36.5°W). A large number of gravity wave was observed from September 2000 to September 2002 and among them 64 wave events were identified as mesospheric bores. The bore front shows a horizontal extension greater than 1000 km, and observed in the airglow layers as a complementary brilliance between the three emissions. At the first time mesospheric bore events were observed and analyzed in the equatorial region. Their predominant characteristics, occurrence, local time dependency, morphology and propagation direction will be presented and discussed.  相似文献   

基于文献计量法的涌潮研究动态分析   总被引：1，自引：0，他引：1       下载免费PDF全文

张舒羽  丁涛  刘进宝  胡玉珊 《海洋学研究》2022,40(1):89-100

以中国知网(CNKI)和Web of Science核心合集数据库为数据源,采用文献计量学方法,借助CiteSpace可视化分析软件,对国内外研究涌潮的国家、机构、作者、载文期刊及关键词等进行分析.在CNKI共检索出433个研究机构的632名作者在239种刊物上发表的652篇文献(1964—2020年),"钱塘江河口"...  相似文献   

Production and Certification of a Unique Set of Isotope and Delta Reference Materials for Boron Isotope Determination in Geochemical,Environmental and Industrial Materials     

Jochen Vogl  Martin Rosner 《Geostandards and Geoanalytical Research》2012,36(2):161-175

Isotopic reference materials are essential to enable reliable and comparable isotope data. In the case of boron only a very limited number of such materials is available, thus preventing adequate quality control of measurement results and validation of analytical procedures. To address this situation a unique set of two boron isotope reference materials (ERM‐AE102a and ‐AE104a) and three offset δ¹¹B reference materials (ERM‐AE120, ‐AE121 and ‐AE122) were produced and certified. The present article describes the production and certification procedure in detail. The isotopic composition of all the materials was adjusted by mixing boron parent solutions enriched in ¹⁰B or ¹¹B with a boron parent solution having a natural isotopic composition under full gravimetric control. All parent solutions were analysed for their boron concentration as well as their boron isotopic composition by thermal ionisation mass spectrometry (TIMS) using isotope dilution as the calibration technique. For all five reference materials the isotopic composition obtained on the basis of the gravimetric data agreed very well with the isotopic composition obtained from different TIMS techniques. Stability and homogeneity studies that were performed showed no significant influence on the isotopic composition or on the related uncertainties. The three reference materials ERM‐AE120, ERM‐AE121 and ERM‐AE122 are the first reference materials with natural δ¹¹B values not equal to 0‰. The certified δ¹¹B values are ?20.2‰ for ERM‐AE120, 19.9‰ for ERM‐AE121 and 39.7‰ for ERM‐AE122, each with an expanded uncertainty (k = 2) of 0.6‰. These materials were produced to cover about three‐quarters of the known natural boron isotope variation. The ¹⁰B enriched isotope reference materials ERM‐AE102a and ERM‐AE104a were produced for industrial applications utilising ¹⁰B for neutron shielding purposes. The certified ¹⁰B isotope abundances are 0.29995 for ERM‐AE102a and 0.31488 for ERM‐AE104a with expanded uncertainties (k = 2) of 0.00027 and 0.00028, respectively. Together with the formerly certified ERM‐AE101 and ERM‐AE103 a unique set of four isotope reference materials and three offset δ¹¹B reference materials for boron isotope determination are now available from European Reference Materials.  相似文献   

钱塘江涌潮区护岸工程的设计及研究     

宣传丽  罗苑 《海洋学研究》1998,16(3):56-63

丁坝在江道整治及护岸工程中已有比较广泛的应用。丁坝的平面布置、结构型式与丁坝自身的稳定性及护岸效果密切相关。本文在对钱塘江涌潮区护岸丁坝的设计作了初步总结的基础上,指出了在丁坝结构上存在的一些问题,提出了相应的改进方案,并结合抢险修复工程,进行了现场原型试验。试验结果表明,本文提出的改进方案是切实可行的。  相似文献   

Turbulence and suspended sediment processes in the Garonne River tidal bore in November 2016     

David Reungoat  Xinqian Leng  Hubert Chanson 《国际泥沙研究》2019,34(5):496-508

A tidal bore is a water discontinuity at the leading edge of a ood tide wave in estuaries with a large tidal range and funneling topography. New measurements were done in the Garonne River tidal bore on 14 15 November 2016, at a site previously investigated between 2010 and 2015. The data focused on long, continuous, high-frequency records of instantaneous velocity and suspended sediment con- centration (SSC) estimate for several hours during the late ebb, tidal bore passage and ood tide. The bore passage drastically modi ed the ow eld, with very intense turbulent and sediment mixing. This was evidenced with large and rapid uctuations of both velocity and Reynolds stress, as well as large SSCs during the ood tide. Granulometry data indicated larger grain sizes of suspended sediment in water samples compared to sediment bed material, with a broader distribution, shortly after the tidal bore. The tidal bore induced a sudden suspended sediment ux reversal and a large increase in suspended sedi- ment ux magnitude. The time-variations of turbulent velocity and suspended sediment properties indicated large uctuations throughout the entire data set. The ratio of integral time scales of SSC to velocity in the x-direction was on average TE,SSC/TE,x 0.16 during the late ebb tide, compared to TE,SSC/ TE,x 0.09 during the late ood tide. The results imply different time scales between turbulent velocities and suspended sediment concentrations.  相似文献   

基于钻孔数据Delaunay-三角网的矿产储量计算     

张渭军  孔金玲  翁晓鹏 《测绘科学》2010,35(4):57-58

针对传统矿产储量计算的不足,在分析平面点集Delaunay-三角网的算法的基础上,提出基于钻孔点集Delaunay-三角网的算法,并以该三角网为基础,在Visual Basic环境利用组件技术,结合钻孔属性数据库,对任意区域矿产储量进行计算,该法不仅克服算术平均法误差大及其他方法难以自动实现的缺点,而且为管理部门的规划和开采设计提供重要参考信息。  相似文献   

钱塘江下游建桥对涌潮景观影响的研究     

卢祥兴  杨火其  曾剑 《海洋学研究》2006,24(1):37-42

采用实测资料分析、潮浪水槽试验、定床模型试验以及已建桥梁对涌潮影响的现场观测等手段,研究了钱塘江下游尖山河段建桥对涌潮景观的影响。研究结果表明,钱塘江河口的喇叭形河湾和庞大的水下沙坎使潮波能量积聚、潮差增大,水深急剧变浅、潮波剧烈变形是形成钱塘江涌潮的主要原因。影响涌潮的主要因素是潮汐、江道地形和治江围涂工程,而建桥不会影响涌潮产生的条件,但由于桥墩的阻水作用,对桥上游500 m范围内的涌潮形态有所影响;当采用合理的桥台设计方案,即阻水面积较小时,对上游涌潮高度的影响仅3 cm左右,故不会影响涌潮的景观。  相似文献   

钻孔柱状图中缓冲线绘制技术   总被引：8，自引：0，他引：8  

迟文学  陈建强  许哲平  王东辉  武峥 《地质科技情报》2006,25(5):87-91

介绍了基于钻孔资料的柱状图自动成图技术,阐述了应用数据库方法对钻孔资料进行管理和钻孔柱状图自动成图系统的总体功能、设计思想、实现方法、关键算法及其特点.重点对钻孔柱状图成图过程中绘制缓冲线的关键算法做了详细的叙述.软件实现了对钻孔资料的管理和自动成图,同时以福建省漳州某第四系钻孔的岩性数据为例,说明该系统绘制出的具有缓冲线结构的钻孔柱状图既美观又实用.  相似文献