由垂直入射脉冲和海底回波反演海底声参数     

郭永刚  王宁  高大治 《中国海洋大学学报(自然科学版)》2006,36(1):112-118

浅海海底声参数是影响声场传播的重要参量。文中根据信号的相位特性对反演稳定性的影响进行了数值模拟;并于2002年8月在黄海海区进行了海底声参数反演实验。利用垂直入射脉冲和海底回波数据进行海底声参数反演,由于海底回波信号随穿透深度增加而导致回波信号的信噪比降低,为了有效地增加海底声阻抗反演深度,提出平滑分段抽取冲激响应,重建声阻抗剖面的方法。结合Hamilton经验公式,分离海底声速、密度,反演结果与海底采样样本分析值、经验值吻合较好。  相似文献   

预测细粒酒精模型冰物理和力学参数的实验关系     

李志军  RISKA Kaj 《海洋与湖沼》2001,32(2):221-224

依据模型冰物理性质控制其力学性质的原则 ,利用能量平衡观点建立了冰内未冻结液体含量同制冰过程中的冰池温度、降温及升温时间、模型冰厚度 (喷雾时间×流量 )的理论关系 ,以其量纲表达式作为预测模型冰物理和力学参数的综合控制指标 ;通过系统测量酒精溶液冰点温度、冰池大厅气温、模型冰温度、冰内未冻液含量、冰密度、冰压缩强度、冰弯曲强度和冰变形模量 ,获得了不同冰点温度模型冰的物理和力学参数同该综合控制指标的实验关系 ;实现了用人为可控制因子定量控制模型冰物理和力学参数的目的  相似文献   

太湖水质参数的遥感监测研究     

汤诗楷  柯长青 《海洋湖沼通报》2007,(2):62-68

以太湖为研究对象,对TM各波段辐射率与水质参数进行拟合,分析了TM各波段经6S模型大气校正和未经校正直接拟合在监测内陆湖泊水质中的可行性。结果表明:TM波段经6S模型校正后能与太湖水质参教进行较好的匹配,同时通过实验得到了太湖地区水质参数的实用性回归公式。  相似文献   

潮坪层序的粒度特征与沉积相划分--以杭州湾庵东浅滩为例   总被引：1，自引：0，他引：1  

郭艳霞  范代读  赵娟 《海洋地质前沿》2004,20(5):9-14

现代潮滩依据多年平均潮位线划分高、中、低潮滩，这对于古代潮坪沉积相研究无实际意义。本文尝试用潮坪层序粒度参数剖面来划分沉积相。潮坪沉积物以粉砂为主，但敏感地反映沉积动力变化的却是粗、细尾部分。因此，在沉积相划分时主要依据粘土、砂含量及平均粒径的变化特征。分选系数是一重要依据，但要考虑絮凝沉积的影响。偏态和峰态变幅小、较复杂，在相划分中只具参考价值。利用粒度参数剖面进行潮坪沉积相划分可广泛应用于古代潮坪层序研究，而且根据中潮坪沉积厚度(x)与平均潮差(y)存在的显著性相关关系：y=1．8314x 157．31(单位cm)，推算古潮差。  相似文献   

粤西水东湾现代沉积环境特征与泥沙搬运路径   总被引：1，自引：0，他引：1  

陈子桑 《热带海洋学报》1996,(3)

对粤西水东湾沉积地貌单元的现代沉积物分布特征分析与泥沙净搬运矢量计算表明，滨面斜坡沉积物主要由砂粒级物质组成，粒级参数Ｍｄ，ＱＤ和ＳＫ具有从海向岸、自东向西变化的总趋势，泥沙净搬运趋势以向岸和西北为主。落潮三角洲沉积物较其邻近滨面斜坡有所粗化，分选从中部向两侧变好，泥沙在落潮流与波浪驱动下沿落潮三角洲边缘向西运动。口门内潮汐通道深槽泥沙净搬运趋势指向湖。湖区的沉积物以泥质为主，分选中等至差，并形成绕涨潮三角洲的泥沙环流元。  相似文献   

GPS接收机与PC机间串口通信的实现   总被引：8，自引：1，他引：8  

公丕波  郝金明  朱伟刚 《海洋测绘》2005,25(3):35-37,41

简要介绍了当前流行的几种串口通信程序开发模式以及GPS接收机广泛采用的NMEA0183通信协议，设计了串口通信类CSerialPortGPS，该类能够实现GPS接收机与Pc机问的串口通信，并且能够对遵循NMEA0183协议的GPS数据进行数据校验和数据提取，并成功地将该类应用到了车载定位导航系统的开发中。  相似文献   

Sensitivity of AUV added mass coefficients to variations in hull and control plane geometry     

Doug Perrault  Neil Bose  Siu O&#x;Young  Christopher D. Williams 《Ocean Engineering》2003,30(5):404-671

The sensitivity of the added mass coefficients of a typical autonomous underwater vehicle (AUV) to changes in geometric parameters was investigated. Qualitative deductions were made concerning the effect of geometric variations. Then the added mass coefficients for several configurations of body geometry were generated for the Canadian Self-Contained Off-the-shelf Underwater Testbed (C-SCOUT) vehicle using the computer program Estimate Submarine Added Mass (ESAM). The changes in the added mass coefficients have direct relationships to the varied parameter. The results presented here are specific to the C-SCOUT, but may be extended to similar axisymmetric bodies.  相似文献   

Successful colonization of the calanoid copepod Acartia tonsa in the oligo-mesohaline area of the Gironde estuary (SW France) – Natural or anthropogenic forcing?     

Valrie David  Benoît Sautour  Pierre Chardy 《Estuarine, Coastal and Shelf Science》2007,71(3-4):429-442

The copepod Acartia tonsa appeared in Europe in the first half of the 20th century and colonized progressively European seas and estuaries, possibly transferred from North Atlantic Coast of America. It had been reported in the polyhaline area of the Gironde estuary for a long time but was first recorded in the oligo-mesohaline area in 1983. Its abundance has been increasing significantly. High abundances of A. tonsa were reported since 1999, supplanting the abundances of its autochthonous congeneric species, Acartia bifilosa. This colonization was characterized by analyzing the mean seasonal variability: (1) for three 5-year periods corresponding to three different steps of A. tonsa appearance (1978–1982, A. tonsa was absent; 1988–1992, low abundances of the species; and 1999–2003, high abundances of A. tonsa) in the oligo-mesohaline area and (2) for three stations distributed along the salinity gradient during the recent period. The aim of this work was to define if this colonization was due to natural or anthropogenic forcing and to evaluate its possible impact on autochthonous zooplanktonic community.Both natural and anthropogenic forcings seem to explain the colonization of Acartia tonsa in the oligo-mesohaline area of the Gironde estuary. First records (1983–1988) could be due to marine water inputs caused by high values of the North Atlantic Oscillation index. The global warming which caused the increase of the summer warm period, the marinisation of the system and the local decrease of the turbidity should have been the key factors favoring the establishment of the species. Anthropogenic forcings as the establishment of the nuclear power plant which locally causes warmer conditions are also important factors explaining the differences of seasonal cycle observed between oligo-mesohaline area and other stations: the seasonal pattern of A. tonsa in the oligo-mesohaline area was indeed characterized by an autumnal peak of abundances which has been observed in other stations and in many North European estuaries, and by a second spring peak that had only been observed in Southern estuaries.The introduction of Acartia tonsa in the Gironde estuary significantly changed the seasonal pattern of autochthonous copepods, by limiting their seasonal abundances without affecting their long-term population stability. Finally, the successful colonization of A. tonsa had led to the spread of the seasonal zooplanktonic production which could have had an impact on fish and shrimp productions.  相似文献   

海洋沉积物声速与其物理-力学参数的相关性     

卢博  梁元博 《热带海洋学报》1991,(3)

通过对海洋沉积物声速及其物理-力学参数相关性的初步分析和研究,可以找到估算沉积物压缩波速Vp和切变波速Vs的经验式,最终为海底沉积物的性质进行声学遥测、为发展海底参数声遥感服务。本文给出了7个较为理想的回归方程。沉积物的物理参数与Vp有密切的关系;力学参数对Vs的预报有较大的作用。若增加物理参数作为修正项,其效果更佳。  相似文献   

电缆沉放深度对地震资料品质的影响     

钟广见  文鹏飞  罗文造  赵庆献  陆敬安 《海洋地质与第四纪地质》2007,27(6):131-134

南海东北部陆坡深水区地质构造、地球物理特性复杂,进行地震资料采集时,如何获得中生界的高品质地震资料至关重要,而选择合适的地震采集参数是关键。7、10和12 m电缆沉放深度试验表明不论从频率分析,还是从子波特征、子波能量各方面均可发现7 m的沉放深度较优。  相似文献