黑潮流域海温适应性观测敏感区诊断方法研究     

崔宝龙  笪良龙  过武宏  韩梅 《海洋科学》2018,42(7):80-86

敏感区诊断是适应性观测的关键问题,集合变换卡尔曼方法(EnsembleTransformKalmanFilter,ETKF)是目前主要的诊断方法之一。将集合变换卡尔曼方法应用于海洋环境适应性观测,根据ROMS海洋模式数据构建海表温度集合预报,以黑潮流域宫古海峡附近海域为验证区进行敏感区诊断计算,分析不同间隔时间条件下敏感区分布情况,结合模拟系统观测试验验证在敏感区进行适应性观测对预报质量的提升效果。结果表明,在诊断所得敏感区内添加观测能够提升预报质量;随时间间隔增大,敏感区向上游区域平移且预报质量提升效果减小;与在验证区整体添加观测相比,敏感区观测对预报质量提升效果基本相同并且观测成本明显减少。  相似文献   

新型珊瑚海水混凝土力学性能试验研究   总被引：2，自引：1，他引：1  

吴彰钰  余红发  麻海燕  章艳  梅其泉  达波  谭永山  华实 《海洋工程》2018,36(3):59-68

为了解决全珊瑚海水混凝土(coral aggregate seawater concrete,简称CASC)的脆性问题,采用碱式硫酸镁水泥(basic magnesium sulfate cement,简称BMSC)为胶凝材料和剑麻纤维为增韧材料制备了一种新型全珊瑚海水混凝土(NCASC),系统测定了基本力学性能,并与普通硅酸盐水泥制备的CASC、碱式硫酸镁水泥砂石混凝土(basic magnesium sulfate cement concrete,简称BMSCC)、普通砂石混凝土(ordinary portland cement concrete,简称OPC)以及普通轻骨料混凝土(lightweight aggregate concrete,简称LAC)的力学性能进行对比。结果表明:立方体抗压强度(f_(cu),m)在15~35 MPa范围内的NCASC的轴心抗压强度(f_c,m)、劈裂抗拉强度(f_(sp),m)与f_(cu),m之间具有较显著的线性关系;对于f_(cu),m为15~35 MPa的混凝土,相同强度NCASC的f_c,m高于OPC、LAC及BMSCC,其f_c,m与f_(cu),m比值最大,大致在0.85~0.96之间,NCASC的f_(sp),m比OPC和LAC高,但比BMSCC低,且随着强度的提高,OPC与NCASC的f_(sp),m间的差距在增大,而LAC和BMSCC与NCASC的f_(sp),m间的差距在缩小;在强度等级C15~C55的范围中,NCASC和CASC的f_(sp),m、f_c,m与f_(cu),m之间的关系基本可以采用相同的线性回归方程来描述,利用这两个回归线性方程得到对应于标准强度等级的CASC和NCASC的f_(sp),m和f_c,m数据,为CASC力学性能研究与结构设计提供参考依据。  相似文献   

Corrigendum to “Climatological mean and decadal change in surface ocean pCO₂, and net sea–air CO₂ flux over the global oceans” [Deep Sea Res. II 56 (2009) 554–577]     

Taro Takahashi  Stewart C. Sutherland  Rik Wanninkhof  Colm Sweeney  Richard A. Feely  David W. Chipman  Burke Hales  Gernot Friederich  Francisco Chavez  Christopher Sabine  Andrew Watson  Dorothee C.E. Bakker  Ute Schuster  Nicolas Metzl  Hisayuki Yoshikawa-Inoue  Masao Ishii  Takashi Midorikawa  Yukihiro Nojiri  Arne Krtzinger  Tobias Steinhoff  Mario Hoppema  Jon Olafsson  Thorarinn S. Arnarson  Bronte Tilbrook  Truls Johannessen  Are Olsen  Richard Bellerby  C.S. Wong  Bruno Delille  N.R. Bates  Hein J.W. de Baar 《Deep Sea Research Part I: Oceanographic Research Papers》2009,56(11):2075-2076

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模糊ISODATA聚类算法在声速剖面自动分类中的应用   总被引：3，自引：0，他引：3  

贾延峰  笪良龙  谢骏 《海洋科学》2009,33(12):103-105

依据中国海浅海区30′按月历史统计声速剖面数据,通过归一化处理和Akima差值采样得到梯度剖面,建立起各方区按月归化后的声速剖面分层梯度样本集,并采用模糊ISODATA聚类算法对声速剖面进行聚类分析.通过对分类结果和类内总方差和的分析表明,聚类参数m值在1.1～2.1之间,并以最远邻系统聚类法结果为初始类中心的模糊分类效果较好.应用该方法对海洋中的声速剖面进行自动分类和区划对海洋环境的战术应用意义重大.  相似文献   

Late glacial fans in the eastern Skagerrak; depositional environment interpreted from swath bathymetry and seismostratigraphy     

Oddvar Longva  Heidi A. Olsen  David J.W. Piper  Leif Rise  Terje Thorsnes 《Marine Geology》2008,251(1-2):110-123

The origin of acoustically transparent fan deposits overlying glacial till and ice-proximal sediments on the southern margin of the Norwegian Channel has been studied using high-resolution seismic-reflection profiles and multibeam bathymetry. The first deposits overlying glacigenic sediments are a series of stacked, acoustically transparent submarine fans. The lack of glaciomarine sediments below and between individual fans indicates that deposition was rapid and immediately followed the break up of the Late Weichselian ice cover. The fans are overlain by stratified glaciomarine sediments and Holocene mud. Because of the uniformity of this drape, the upper surface of the fan deposits is mimicked at the present seafloor, and the bathymetric images clearly show the spatial relationship of the fans to bedrock ridges and the presence of braided channel-levee systems on the surface of the youngest fans. The acoustically transparent character of the fan deposits indicates that they comprise silt and clay, and their lobate form and lack of internal stratification indicates that they were deposited by debris flows. The channel-levee morphology indicates deposition from more watery hyperconcentrated fluid flows. The fan sediments were either derived from 1) erosion of Mid Weichselian lake deposits in southern Skagerrak or 2) from Late glacial ice-margin lake deposits, ponded against the Norwegian Channel ice stream, which collapsed catastrophically when the lateral support was removed as the ice disintegrated. Fans composed almost exclusively of fine-grained sediment need not, therefore, rule out an origin in a deglacial setting relatively close to the former margins of glaciers and ice sheets.  相似文献   

黑潮锋区的水温分形特征研究     

韩梅  周艳霞  笪良龙 《海洋科学》2008,32(5):28-31

借助GIS ArcView软件分析提取黑潮锋区域,将一定间隔的经纬度点的温度值生成等值线以此为研究对象,应用网格法计算了20°～30°N,120°～130°E范围内黑潮锋区50m和100m深处水温的分维值,100m深处的分维值波动较50m深处小,但整体上分维值较50m深处大。计算结果符合黑潮锋区强度的实际分布情况,初步认为分形维数能够表征黑潮锋强度,分维值随黑潮锋强度的增大而增大。  相似文献   

海岸水边线提取方法在GF-2卫星影像中的适应性研究     

李阳东  温远超  笪亨融  梁君豪 《海洋通报》2022,(3):281-289

准确提取海岸水边线是海岸线变迁研究中必不可少的基本工作。本文以海南省陵水黎族自治县2016年的GF-2影像为数据源,在大气校正和正射校正等预处理的基础上,结合数学形态学处理等方法,采用NDWI (Normalized Difference Water Index)阈值法、ISOADTA (Iterative Self-Organizing Data Analysis Technique Algorithm)、SVM (Support Vector Machine)和面向对象法（Object-Oriented Classification,OOC）等4种不同方法来对海岸水边线进行提取,并对其提取结果进行定性和定量评估,进而分析比较了这4种方法在提取人工海岸、砂质海岸和基岩海岸等3种不同海岸类型的水边线时的提取效果和提取精度。结果表明,SVM方法在3种海岸水边线上的总体提取效果最好,总体提取精度最高。  相似文献   

Watson: A new link in the HE iron chain     

Edward Olsen  Andrew Davis  Roy S. Clarke  Ludolf Schultz  Hartwig W. Weber  Robert Clayton  Toshiko Mayeda  Eugene Jarosewich  Paul Sylvester  Lawrence Grossman  Ming-Sheng Wang  Michael E. Lipschutz  Ian M. Steele  James Schwade 《Meteoritics & planetary science》1994,29(2):200-213

Abstract— Watson, which was found in 1972 in South Australia, contains the largest single silicate rock mass seen in any known iron meteorite. A comprehensive study has been completed on this unusual meteorite: petrography, metallography, analyses of the silicate inclusion (whole rock chemical analysis, INAA, RNAA, noble gases, and oxygen isotope analysis) and mineral compositions (by electron microprobe and ion microprobe). The whole rock has a composition of an H-chondrite minus the normal H-group metal and troilite content. The oxygen isotope composition is that of the silicates in the HE iron meteorites and lies along an oxygen isotope fractionation line with the H-group chondrites. Trace elements in the metal confirm Watson is a new HE iron. Whole rock Watson silicate shows an enrichment in K and P (each ～2X H-chondrites). The silicate inclusion has a highly equilibrated igneous (peridotite-like) texture with olivine largely poikilitic within low-Ca pyroxene: olivine (Fa₂₀), opx (Fs₁₇Wo₃), capx (Fs₉Wo₄₁) (with very fine exsolution lamellae), antiperthite feldspar (An_1–Or₅) with <1 μm exsolution lamellae (An_1–3Or_>40), shocked feldspar with altered stoichiometry, minor whitlockite (also a poorly characterized interstitial phosphate-rich phase) and chromite, and only traces of metal and troilite. The individual silicate minerals have normal chondritic REE patterns, but whitlockite has a remarkable REE pattern. It is very enriched in light REE (La is 720X C1, and Lu is 90X C1, as opposed to usual chonditic values of ～300X and 100–150X, respectively) with a negative Eu anomaly. The enrichment of whole rock K is expressed both in an unusually high mean modal Or content of the feldspar, Or₁₃, and in the presence of antiperthite. Whole rock trace element data for the silicate mass support the petrography. Watson silicate was an H-chondrite engulfed by metal and melted at > 1550 °C. A flat refractory lithophile and flat REE pattern (at ～1x average H-chondrites) indicate that melting took place in a relatively closed system. Immiscible metal and sulfide were occluded into the surrounding metal host. Below 1100 °C, the average cooling rate is estimated to have been ～1000 °C/Ma; Widmanstätten structure formed, any igneous zoning in the silicates was equilibrated, and feldspar and pyroxene exsolution took place. Cooling to below 300 °C was completed by 3.5 Ga B. P. At 8 Ma, a shock event took place causing some severe metal deformation and forming local melt pockets of schreibersite/metal. This event likely caused the release of Watson into interplanetary space. The time of this event, 8Ma, corresponds to the peak frequency of exposure ages of the H-chondrites. This further confirms the link between HE irons and the H-chondrites, a relationship already indicated by their common oxygen isotope source. Watson metal structures are very similar to those in Kodaikanal. Watson, Kodaikanal and Netschaëvo form the young group of HE meteorites (ages 3.7 ± 0.2 Ga). They appear to represent steps in a chain of events that must have taken place repeatedly on the HE parent body or bodies from which they came: chondrite engulfed in metal (Netschaëvo); chondrite melted within metal (Watson); and finally melted silicate undergoing strong fractionation with the fractionated material emplaced as globules within metal (Kodaikanal). Watson fills an important gap in understanding the sequence of events that took place in the evolution of the IIE-H parent body(ies). This association of H-chondrite with HE metal suggests a surface, or near surface process-a suggestion made by several other researchers.  相似文献   

Barringer Medal Citation for William A. Cassidy     

Edward J. Olsen 《Meteoritics & planetary science》1996,31(4):431-432

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基于Python实现正射影像图的质量检查与精度统计方法研究     

答星  杨晓东  任杨  滕松  孔祥娟 《测绘与空间地理信息》2017,(6):43-46

DOM成果质量检查是数字测绘成果质量检查的核心内容之一,本文介绍了DOM质量检查主要的核查内容、方法和评估公式,提出了利用Python语言和FME模板设计对质量检查中需要人工核查的重要环节进行技术优化,实现检查图、表等统计信息的自动化生成,并对流程优化过程中的重要环节进行阐述,有效地提高了DOM成果质量检查效率。  相似文献