塘沽海区海底地形的SAR影像仿真与反演研究

利用袁业立、金梅兵(1997)提出的海底地形SAR影像仿真与反演模型，对渤海塘沽海区的一张Radarsat SAR影像进行了仿真和水深反演研究。研究结果表明：仿真影像与真实SAR影像基本吻合，反演水深与实际水深也有较好的一致性；进一步证实了袁业立(1997)SAR成像机理的正确性和在中国近海利用SAR影像进行浅海水深探测的可行性。     

Dereverberation of marine reflection seismic data by a spatial combination of predictive deconvolution and velocity filtering

Contamination of seismic reflection records at early times by first-order water reverberations can be especially severe during survey operations over hard and flat sea floors on the continental shelf or in lake environments. A new dereverberation scheme based on two classical techniques — predictive deconvolution and velocity filtering — has been developed to address this problem. The techniques are combined spatially to take advantage of their complementary offset- and time-dependent properties. Stage I of the scheme consists of applying predictive deconvolution at short offset. The data are previously conditioned by a normal moveout correction with the water velocity which restores the periodicity of the reverberations in the offset-time plane and enhances the performance of deconvolution. Stage II of the scheme involves velocity filtering in the common-midpoint domain which is particularly effective at long offset where the moveout difference between primary reflections and reverberations is largest. The dereverberation scheme is well suited for the initial processing of large volumes of data due to the general availability of cost-effective deconvolution and velocity filtering algorithms in seismic processing software packages. Practical implementation issues are illustrated by a field example from the GLIMPCE survey in Lake Superior.Lithoprobe Publication No. 475.     

长江口徐六泾悬浮细颗粒泥沙絮凝体特性

2003年6月14日-22日, 利用现场激光粒度仪LISST-100在不扰动颗粒物的情况下, 于长江口徐六泾定点连续观测了洪季大、小潮表层粘性悬浮细颗粒泥沙絮凝体的实有粒径、体积浓度, 配合OBS-3A现场测量的悬沙浓度计算了现场絮凝体的有效密度和静水沉速.观测结果显示, 徐六泾大、小潮表层絮凝体体积浓度、粒径、有效密度和静水沉速的平均值分别为98.0 μl/L、39.8 μm、1173 kg/m^3、1.14 mm/s和70.8 μl/L、64.4 μm、919 kg/m^3、2.32 mm/s.研究表明： ①长江口徐六泾表层絮凝体体积浓度主要受水流流速影响, 再悬浮现象明显, 体积浓度过程线滞后流速过程线, 落潮期间滞后10-30 min, 涨潮则滞后30-50 min; ②小于一定流速时絮凝体平均粒径随流速增大而增大, 大于一定流速时絮凝体平均粒径则随流速增大而减小, 徐六泾大、小潮表层絮凝体在50 cm/s的垂线平均流速时出现平均粒径与垂线平均流速关系的转折; ③徐六泾大、小潮表层絮凝体平均粒径在体积浓度75 μl/L时出现平均粒径与体积浓度关系的转折, 体积浓度小于75 μl/L时粒径随体积浓度增加而增大, 超过75 μl/L时粒径随体积浓度的增加变化不明显; ④絮凝体有效密度由粒径大小控制, 粒径大, 有效密度小, 反之亦然, 粒径和有效密度共同决定絮凝体静水沉速, 有效密度和沉速与平均粒径之间均存在良好的幂指数关系.     

赤道西太平洋大气边界层的诊断分析

利用１９９３年ＥＮＳＯ事件爆发（４月）前酝酿时期“热带大洋与全球大气－海洋耦合响应试验”强化观测阶段“向阳红五号”科学考察船１５５°Ｅ，２°Ｓ定点海洋气象和高空大气探测资料，分析了赤道西太平洋大气边界层特征。结果表明：赤道西太平洋上空辐合对流区边界层内也有等温或逆温层存在，大气边界层物理参数变化与大尺度海－气变异有密切关系，赤道太平洋沃克环流加强、东移，边界层上部逆温层出现概率明显增大，边界层内高湿层湿度减小。另外，边界层内实测风速、风向廓线随高度的变化基本上不服从Ｅｋｍａｎ规律，但由其平均，分量合成得到的平均风随高度的变化却基本符合Ｅｋｍａｎ规律。     

九州西侧海域129°E断面的流速和温盐结构特征

根据中、日合作黑潮调查研究期间（1987－1993年）在九州西侧海域获得的水文资料，计算了129°E断面的地转流速和流量。着重提出129°E断面北侧存在一支较稳定的西向流；分析这支西向流的去向，指出它是向对马暖流输送黑潮水的重要途径；给出了这支西向流及黑潮通过该断面的流速、流轴、流幅及流量的变化特征。     

Vertical Sound Velocity Transition in the Coral Reef Core and Its Significance of Indicating Facies

On the basis of the sound velocity measurements of the coral reef core from Nanyong No.1 well of Yongshu Reef in the Nansha Islands,the paper studies the relations between the vertical sound velocity transition features in the coral reef core and the corresponding stratigraphic depositional facies change as well as stratigraphic gap of erosion,analyses the cause of the sound velocity transition,expounds the concrete process of the sea level change resulting in the stratigraphic gap of erosion and facies change in the coral reef and explains the relations between the vertical sound velocity transition in the coral reef core and the corresponding stratigraphic paleoclimate and the sea level change.This study is of important practical value and theoretical significance to the island and reef engineering construction and the acoustic logging for oil exploration in the reef limestone area as well as the paleoceanographic study of the marginal sea in the westerm Pacific Ocean.     

Velocity-Interface Structure of the Southwestern Ryukyu Subduction Zone from EW9509-1 OBS/MCS Data

A wide-angle seismic survey, combining ocean-bottom seismometers (OBS) and multi-channel seismic (MCS) profiling, was implemented in the southwestern Ryukyu subduction zone during August and September 1995. In this paper, we present the data analysis of eight OBSs and the corresponding MCS line along profile EW9509-1 from this experiment. Seismic data modeling includes identification of refracted and reflected arrivals, initial model building from velocity analysis of the MCS data, and simultaneous and layer-stripping inversions of the OBS and MCS arrivals. The velocity-interface structure constructed along profile EW9509-1 shows that the northward subduction of the Philippine Sea Plate has resulted in a northward thickening of the sediments of the Ryukyu Trench and the Yaeyama accretionary wedge north of the trench. The boundary between the subducting oceanic crust and the overriding continental crust (represented by a velocity contour of 6.75 km/s) and a sudden increase of the subducting angle (from 5 degrees to 25 degrees) are well imaged below the Nanao Basin. Furthermore, velocity undulation and interface variation are found within the upper crust of the Ryukyu Arc. Therefore, the strongest compression due to subduction and a break-off of the slab may have occurred and induced the high seismicity in the forearc region. This revised version was published online in November 2006 with corrections to the Cover Date.     

Estimation of Water Particle Velocities by Empirical Transfer Function

-In previous and this studies it appears that the linear and nonlinear wave theory can notaccurately and easily predict the water particle velocities.Therefore,different from the theoretical consider-ations,in this study we have attempted to determine the transfer function empirically.Laboratory experi-ments were performed under various wave conditions.The empirical formulas of the transfer function ofthe wave height,angular frequency and water particle velocity were obtained on the basis of these test databy dimensional analysis and regression analysis.In intermediate and deep water depth conditions,thetransfer function was only a function of a nondimensional parameter which is composed of the angular fre-quency,the depth of the velocity gauge under the still water level,water depth and the acceleration of grav-ity.Finally,the empirical formulas were compared with experimental data and observational data formpresent and Cavaleri's(1978)studies.The empirical formulas were found to be in sufficient correl     

近58a来影响和登陆浙江的热带气旋统计特征分析

本文利用1949-2006年热带气旋资料,对58a来影响和登陆浙江热带气旋的登陆位置、登陆时间的年际、月际和日变化、登陆后的移速及路径变化与降水中心分布的关系、登陆后维持和衰减情况等进行了统计分析.统计结果表明：影响和登陆浙江的热带气旋有较明显的年际、月际和日变化特征;登陆浙江的热带气旋陆上维持时间与登陆时的强度正相关,登陆后12h内热带气旋衰减较快;登陆后移向偏北分量大的或移速加快的热带气旋,主要降水区出现在路径右侧的可能性大.     

长江河口三角洲区有孔虫沉降速度试验

作者对有孔虫壳体沉降速度进行了测试和研究,提出了不同属种有孔虫的壳径与沉降速度相关方程,引进了“当量直径”的概念,并用于长江口三角洲地层中的化石群,提出了解释潮汐河口有孔虫埋葬群的形成机理,从而定量的研究和辨别三角洲地层中的原地埋葬和异地埋葬化石群。