Reinforcement of Soft Foundation with Geotextile and Observation for Sea Dike Project of Zhapu Port

1 .IntroductionTheZhapuPortissituatedonthenorthbankoftheHangzhouBay ,nearZhapuTowninPinghuCity ,Zhejiangprovince .Asthefirststepofconstruction ,reclamationwasaccomplishedinthehinter landoftheharbor.Theborderdikeofafulllengthof 1 2 71mislocatedinthetidalregionoftheHangzhouBay .ThepreliminarydesignofthisprojectwascompletedinJune 1 986 ,anditsconstructionbeganinJuly 1 986 ,andwascompletedinMarch 1 991 .TheseadikewasbuiltontheQ4marinedepositofsaturatedsoftclaywithathicknessofabout2 7mandgeo…     

Data assimilation methods for estimating a heterogeneous conductivity field by assimilating transient solute transport data via ensemble Kalman filter

An ensemble Kalman filter (EnKF) is developed to identify a hydraulic conductivity distribution in a heterogeneous medium by assimilating solute concentration measurements of solute transport in the field with a steady‐state flow. A synthetic case with the mixed Neumann/Dirichlet boundary conditions is designed to investigate the capacity of the data assimilation methods to identify a conductivity distribution. The developed method is demonstrated in 2‐D transient solute transport with two different initial instant solute injection areas. The influences of the observation error and model error on the updated results are considered in this study. The study results indicate that the EnKF method will significantly improve the estimation of the hydraulic conductivity field by assimilating solute concentration measurements. The larger area of the initial distribution and the more observed data obtained, the better the calculation results. When the standard deviation of the observation error varies from 1% to 30% of the solute concentration measurements, the simulated results by the data assimilation method do not change much, which indicates that assimilation results are not very sensitive to the standard deviation of the observation error in this study. When the inflation factor is more than 1.0 to enlarge the model error by increasing the forecast error covariance matrix, the updated results of the hydraulic conductivity by the data assimilation method are not good at all. Copyright © 2012 John Wiley & Sons, Ltd.     

Excel在形变观测数据处理中的应用

利用Excel的数据处理功能以及自带的"Visual Basic "语言进行二次开发,然后以宏的形式连接在Excel界面上,实现了形变观测数据的处理.     

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北斗三号在轨测试卫星观测数据分析

采用自编数据处理算法对部分iGMAS与MGEX站点的观测数据进行分析，结果表明，北斗新信号表现优异，数据完整率和信噪比弱于GPS，多路径误差和伪距噪声与GPS相当，电离层延迟变化率优于GPS。总体而言，北斗三号与GPS处于同一水准。     

海底沉积物孔隙压力原位长期观测技术回顾和展望

海底沉积物孔隙压力对海底地质灾害过程反应敏感,是表征海床稳定性的一个重要指标,通过海底沉积物的孔隙压力观测可以判断海床的稳定状态,对于海底地质灾害预测预警具有重要意义。海底沉积物孔隙压力观测存在(1)超高背景压力下的高精度测量;(2)贯入过程传感器超量程破坏;(3)系统长期供电及传感器漂移;(4)深海海底布放和回收等技术难点。国际上海底孔隙压力观测技术从20世纪60年代开始发展,逐渐形成了系列核心监测技术和成熟的商业化设备产品。挪威岩土工程研究所NGI与美国伊利诺伊大学共同研发的NGI-Illinois压差式孔隙压力观测系统,是已知最早的海底沉积物孔隙压力观测设备。此后,美国地质调查局USGS、美国桑迪亚国家实验室、英国牛津大学等相继研发了不同结构的观测设备,覆盖浅海到深海。其中,英国海洋科学研究所研发成功的深海孔隙压力原位长期观测设备PUPPI是一个重要的历史节点,该设备能够在6 000 m水深的环境中连续运行一年,成为当时最成功的海底孔隙压力观测设备,其现代化的设备结构和设计理念被后续的观测设备广为借鉴。21世纪以来,得益于海洋科学技术的整体进步,国际孔隙压力观测技术发展呈现加速趋势。法国海洋开发研究院IFREMER研发的Piezometer系列孔隙压力观测探杆,代表了当今世界的先进水平,可能是目前应用次数最多的海底孔隙压力观测设备。我国在深海探测、观测技术领域起步较晚,在深海沉积物孔隙压力原位长期观测技术方面几乎空白,发展很不成熟。其中,中国海洋大学、自然资源部第一海洋研究所等单位进行了较多的探索性研发工作。近年来,以港珠澳大桥建设、南海天然气水合物试采等为标志的大批国家级海洋建设项目如火如荼,深海油气矿产资源开发、深海天然气水合物开采利用等海洋新兴产业快速起步,深海孔隙压力原位长期监测关键核心技术等“卡脖子”问题仍然突出,严重制约了我国海洋工程产业发展的步伐。因此,迫切需要发展具有自主知识产权和关键核心技术的国产深海沉积物孔隙压力原位长期监测技术。本文回顾了国际、国内海底孔隙压力观测技术的相关研究进展,旨在分析总结孔隙压力观测技术及其应用中涉及的一些核心技术和亟待解决的关键问题,以期为我国该项技术的发展和应用提供借鉴。     

Low frequency variations in currents on the southern continental shelf of the Caspian Sea

The Caspian Sea (CS) is the largest enclosed basin in the world, located inside the Eurasian continent in the Northern Hemisphere. Although there have been few studies of the dynamics of the coastal zone in the CS, observations show that oscillations with periods from 2–3 days to 1–3 weeks dominate. These oscillations are presumed to be related to the synoptic variability of direct wind impact and to coastally-trapped waves (CTW). Here, we describe and interpret current meter observations on the continental margins of the southern CS from 2012 to 2014 to identify and characterize CTW there. Time series analysis provides evidence for both remote and locally wind-forced eastward traveling signals with time lags consistent with CTW theory. A wind-forced model with two CTW modes is able to reproduce the structure, amplitudes, and phases of observed alongshore current fluctuations, explaining half of the variance at frequencies less than 1 cpd. Remote forcing effects are present at all times, but are most striking when the local winds are weak, as in summer. The CTW calculations also suggest that the source region for the remote forcing may extend farther north along the west coast of the CS.     

卫星资料揭示的青藏高原对流层上层温度气候演变趋势特征

利用1982—2016年MSU/AMSU-A亮温资料,分析了青藏高原地区对流层上层温度的气候趋势及其演变特征,并利用ERA-Interim和NCEP-R2再分析资料的相应高度大气温度资料进行了对比分析。结果表明,青藏高原地区对流层高层卫星亮温资料总体表现为逐渐增暖现象,这与再分析资料的对应层次大气温度变化有很好的相似性。基于集合经验模式分解方法 EEMD的非线性趋势分析表明,青藏高原地区对流层上层亮温的增温首先出现在青藏高原中部,随着时间演变,增温现象逐渐向青藏高原四周扩散,最后在整个青藏高原地区都出现了一致增温现象。相比于NCEP-R2再分析资料而言,ERA-Interim再分析资料300 h Pa大气温度的演变趋势与观测亮温有很好的相似性,只是增温现象是首先在青藏高原附近,随着时间推移,增温现象逐步向周边地区扩张,最终整个青藏高原地区出现了整体升温现象。但是NCEP-R2再分析资料则是与上述两种资料的温度演变特征有很大的差异,其300 h Pa高度大气温度在前20年表现为明显的降温特征,在最近10年才出现了增温,并逐步向周边地区扩张的现象。