黄河口埕岛海域悬浮沉积物沉降规律原位观测北大核心CSCD

运用时间序列沉积物捕获器,原位捕获了黄河口埕岛海域某观测点的沉降沉积物,并结合同步的波浪、海流、水深等水动力参数观测以及后续土样粒径分析等研究手段,计算了沉降通量,推断了沉降沉积物的来源,并结合理论计算探讨了悬浮沉积物沉降过程的影响因素以及沉降量在再悬浮量中所占的比例。研究结果表明:黄河口埕岛海域的悬浮沉积物沉降通量约为120~280g·m^(-2)·d^(-1),与该海域的再悬浮通量有着很好的正相关关系,推测很可能主要来源于海底沉积物的再悬浮;在该海域,即使过剩剪切力持续大于0,悬浮沉积物仍然会发生沉降,并且可以大于过剩剪切力小于0时的沉降量,推测与该地区粉质土海床的液化特性有关;再悬浮沉积物大约有5%发生原位沉降,绝大部分沉积物保持悬浮或者被输运至异地,这与该地区海底遭受强烈侵蚀的现象相一致。     

桩基高层建筑施工中的沉降测量

结合两幢位于山坡且楼体外有隔热保温敷层的桩基高层住宅楼施工测量,探讨了桩基高层建筑施工中的沉降测量及数据处理分析方法;对沉降观测中需要特别注意的若干问题进行了分析探讨,特别指出了:相对于普通的沉降测量,由于某些桩基可能受到上拔力的作用,基准点的稳定性更重要,其布设应更科学慎重;一些不依赖于基准点的数据处理和分析方法可能会导致错误的分析结果。分析结果也为研究滩涂、湿地、软土地区常见的桩基础建(构)筑物随荷载的变化提供了一个具体参考例证。     

我国海洋观测技术三十年发展的回顾和展望

本文回顾了我国海洋观测技术发展三十年的基本情况、主要成就，结合全球海洋观测系统（ＧＯＯＳ）计划的实施，展望我国海洋观测技术今后的发展。     

面向原位数据的海洋观测客户端软件设计与实现

原位数据在海洋观测过程中具有重要作用。本文针对面向原位数据的海洋观测客户端软件开发复用率低、不同观测平台之间数据通用性差的问题,结合已有的海洋观测软件,利用ActiveX控件开发技术、WebGIS以及WebService技术,提出面向原位数据的海洋观测客户端软件设计模型,通过原型系统验证了模型设计的有效性。该设计模型对于面向原位数据的海洋观测客户端软件的高效率开发具有重要作用。     

试探如何提高海流观测资料的可靠性

本文根据工作实践,对海流观测资料的可靠性和具体观测方法作出分析,并提出问题。对今后改进海流观测方法和提高资料可靠性提供了具体措施和建议,以供同行交流。     

利用CCD成像技术进行渤海海冰观测探讨

利用CCD成像技术进行走航海冰观测是国际南极科学委员会海冰过程与气候项目制定的南极海冰观测方法的一部分.本文介绍了利用CCD成像技术进行海冰观测及其图像信息提取的基本原理,分析了该项技术在南北极海冰走航观测应用实践中的成功经验及问题所在,讨论了南北极与渤海冰情和调查作业环境的差异,探讨了利用CCD成像技术进行渤海海冰观测的应用前景.     

基于集合同化方法的南海北部最优观测实验

根据集合同化理论及最优观测方法,应用基于ROMS模式的南海北部区域模拟结果作为集合样本,对该区域的最优观测廓线以及最优观测航次进行了评估和选择.最优观测方法是一种不需要直接同化观测,而通过最小化分析场误差方差理论值来选择最优观测点的方法.最优观测方法根据卡曼滤波理论中协方差矩阵的更新方程,使用一组模式或观测得到的历史样...     

热带气旋海上观测进展

热带气旋的精准预报具有重要的社会、经济效益,是科学家研究与关注的重要问题。为了更充分、更全面地认识热带气旋变化规律,及时发现处于发生、发展期的热带气旋,实现更精准的预报,热带气旋的海上观测是必不可少的。对热带气旋的观测伴随技术的进步,表现出从点到面、从面到综合观测的趋势。本文从星基观测、空基观测、移动观测、锚系观测以及综合观测试验等方面,简述了热带气旋海上观测方面取得的应用进展。上述不同观测平台和手段,在实际应用中表现出了不同的价值与能力,且均有其优缺点。研究需求及综合观测试验结果证明将陆基、海基、空基和星基平台和设备进行全方位立体组网观测,以发挥各自的优势是热带气旋海上观测未来的发展趋势。     

中国海洋环境观测系统的建设与发展

根据海洋减灾防灾工作的需要,建设与发展中国海洋环境观测系统已成我国海洋事业发展的当务之急。为此,本文就建立一个完整的海洋环境体观测框架的结构,加速开发与研究观测技术所需的仪器装备和建产一个现代化的观测资料通讯网络提出概要介绍,供有关部门和同行参考。     

发展海洋观测高技术

本文概述了海洋观测高技术的现状和发展趋势，论述了海洋观测技术在我国国民经济建设和社会发展中的战略地位，社会需求和市场前景，指出了发展海洋观测高技术的风险和困难。     

渤海湾西岸潮间带现代沉积速率研究

利用渤海湾西岸潮间带柱状沉积物的210Pb_ex和137Cs活度测定结果,计算了潮间带现代沉积物的平均沉积速率,结果表明,渤海湾西岸潮间带砂质区(道沟子至独流减河)1955～1963年的沉积速率为3.43～4.06cm/a,1963年以来的平均沉积速率为0.65～1.59cm/a;泥质区(歧口附近)的平均沉积速率约为1.81cm/a.上述结果说明潮间带砂质区在20世纪50～60年代发生快速沉积作用,60年代之后沉积作用变缓.这可能是由于华北地区在该时段具有丰沛的降水和入海水沙,为潮间带沉积物提供了丰富的物源.60年代以后沉积作用变缓可能是自然和人类活动引起的入海水量减少和由此导致的物源减少的结果.     

G882光泵磁力仪静态噪声水平检验与分析

G882光泵磁力仪主要用于海洋磁探作业,也常常作为地磁日变观测仪器使用。无论哪种工作需要,使用前都应对仪器稳定性测试,借此了解仪器性能和工作指标。依据相关技术规范和计算方法,结合多年野外日变实测资料,可对该型磁力仪基本性能指标的静态噪声进行计算检验与统计,同时分析环境、数据来源等外部因素对计算结果的影响程度,综合评价此项性能指标限值的合理性。     

A model of the effects of sedimentation rate on the stability of Mississippi Delta sediments

High sedimentation rates on the subaqueous delta of the Mississippi River create localized sediment instabilities that result in downslope movement through well-defined chutes or gullies. A simplified kinematic wave equation model that neglects second-order effects such as diffusion treats the failure mechanism as a sedimentation and slope oversteepening process and sediment motion as a propagating kinematic wave. The model allows estimation of sedimentation rates necessary to initiate slope failures for a range of observed depths of basal shear planes. Model results indicate that slope oversteepening is a viable failure mechanism and a thin surface sediment layer may be moving downslope in a slow, continuous motion.     

台湾海峡西部表层沉积地球化学元素分布及砂矿成矿显示

本文研究了台湾海峡西部海底表层沉积物中的２０种微量元素分布特征，划分４种组合类型。Ｚｒ、Ｌａ、Ｙ、Ｎｂ、Ｔｉ元素高含量区具有海底锆、钛砂矿可能成矿的良好显示，为海底砂矿找矿提供地球化学依据。     

海南岛近海海域7个沉积岩芯的现代沉积速率及其分布特征

利用多道α能谱仪,对2005年8～9月在海南岛近海采集的7个沉积岩芯进行了210Pb的沉积速率测定,探讨了海南岛近海陆架上现代沉积速率的区域性分布特征,结果表明:位于港湾内的B1168站位由于沉积物供应充足,有最高的沉积速率,达2.9 cm/a;位于河口海湾附近且受沿岸流影响的B289站位,有很高的沉积速率,可达1.6 cm/a,沉积环境较稳定;位于西南海底沙脊区北缘且靠近昌化江河口的B97、B135、B10站位也有较高沉积速率,分别达到1.0、0.89和0.47 cm/a,在表层都出现了210Pb放射性活度倒置的现象,表明所处区域有较强混合作用;处于西南外陆架的C4站位受北部湾环流影响,沉积速率为0.6 cm/a;位于东部外陆架的B377站位处于上升流区,沉积速率较低,为0.21 cm/a.可见,海南岛近海陆架上的现代沉积速率存在着明显的区域分布:在物质来源丰富的沿岸流作用区和河口区附近,现代沉积速率很高;在陆架环流沉积作用区,现代沉积速率也较高;在水深较大的外陆架上,由于沉积物供应相对匮乏,沉积速率一般较低;在近岸潮流沙脊区,由于水动力很强,无法形成现代细粒沉积.同时,在陆架上,沉积速率有随着水深的增加而降低的趋势.由此可见,海南岛近海海域的沉积速率与该区的物质供应、水动力条件和海底地形等因素有密切关系.     

Depositional history of the Helgoland mud area,German Bight,North Sea

The Helgoland mud area in the German Bight is one of the very few sediment depocenters in the North Sea. Despite the shallowness of the setting (<30 m water depth), its topmost sediments provide a continuous and high-resolution record allowing the reconstruction of regional paleoenvironmental conditions for the time since ~400 a.d. The record reveals a marked shift in sedimentation around 1250 a.d., when average sedimentation rates drop from >13 to ~1.6 mm/year. Among a number of major environmental changes in this region during the Middle Ages, the disintegration of the island of Helgoland appears to be the most likely factor which caused the very high sedimentation rates prior to 1250 a.d. According to historical maps, Helgoland used to be substantially bigger at around 800 a.d. than today. After the shift in sedimentation, a continuous and highly resolved paleoenvironmental record reflects natural events, such as regional storm-flood activity, as well as human impacts at work at local to global scales, on sedimentation in the Helgoland mud area.     

Basic regularities of the process of sedimentation of suspended organic matter in the shallow-water zones of the seas at middle latitudes

On the basis of analysis of literature data, we consider the regularities of sedimentation of suspended organic matter in shallow waters. The seasonal variability in sedimentation is demonstrated, and its scheme is constructed involving such classes of organic compounds as suspended amino acids, fatty acids, and hydrocarbons. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

Modern sedimentation rates in the intertidal zone on the west coast of the Bohai Gulf

On the basis of the measurement of ^210Pbcx and ^137Cs activities in the sediment cores taken from the intertidal zone on the west coast of the Bohai Gulf, the average sedimentation rates of modern sediments are calculated. The results indicate that in the sandy area of the intertidal zone (from Daogouzi to the Duliujian River), the sedimentation rate from 1955 to 1963 is 3.43～4.06 cm/a, and is within the range of 0.65～1.59 cm/a since 1963. The average sedimentation rate in the muddy area (around Qikou) is approximately 1.81 cm/a.The results above suggest that the sandy area of the intertidal zone has experienced rapid sedimentation from the 1950s to the 1960s,and the sedimentation slows down after the 1960s, and the sedimentation rates increase from north to south spatially. The rapid sedimentation from the 1950s to the 1960s in the sandy area is due to the fact that North China has plentiful precipitation during this period and the intertidal zone is supplied with abundant matter sources for sedimentation. After the 1960s, the weakened sedimentation may be a result of the reduction of sand transported to the intertidal zone, which is a consequence of diminished rainfall in North China and intensive human activities in the Haihe basin.     

Examination of observation impacts derived from observing system experiments (OSEs) and adjoint models

With the adjoint of a data assimilation system, the impact of any or all assimilated observations on measures of forecast skill can be estimated accurately and efficiently. The approach allows aggregation of results in terms of individual data types, channels or locations, all computed simultaneously. In this study, adjoint-based estimates of observation impact are compared with results from standard observing system experiments (OSEs) using forward and adjoint versions of the NASA GEOS-5 atmospheric data assimilation system. Despite important underlying differences in the way observation impacts are measured in the two approaches, the results show that they provide consistent estimates of the overall impact of most of the major observing systems in reducing a dry total-energy metric of 24-h forecast error over the globe and extratropics and, to a lesser extent, over the tropics. Just as importantly, however, it is argued that the two approaches provide unique, but complementary, information about the impact of observations on numerical weather forecasts. Moreover, when used together, they reveal both redundancies and dependencies between observing system impacts as observations are added or removed from the data assimilation system. Understanding these dependencies appears to pose an important challenge in making optimal use of the global observing system for numerical weather prediction.     

海洋观测方法之研究

本文讨论了海洋观测技术的定义,厘清了其与海洋探测技术和海洋监测技术的关系,并在认识海洋观测数据本质的基础上,从技术性、实时性、经济性和适用性等4个方面,来讨论海洋观测方法。本文研究表明,抓着观测数据的本质保障观测数据的质量;观测手段特别是平台技术决定观测技术的实时性;实时性反映海洋观测任务的需要及观测技术的水平;经济性决定观测技术的选用;适用性进一步决定海洋观测技术的最佳形式,甚至衍生出新的观测技术。