旁侧声呐在海底探测中的应用和工作船动态定位施工技术   总被引：1，自引：0，他引：1  

李安龙  曹立华  李广雪  杨荣民 《中国海洋大学学报(自然科学版)》2006,36(2):331-335

随着海洋工程建设及海上事故和海难的增多,日益增加的海底障碍物给海上安全生产和航运带来了前所未有的挑战和安全隐患,需要进行海上搜寻和水下探摸与处理。旁侧声呐和动力定位船的配合使用是处理这类问题的最佳选择,但租用动力定位船费用昂贵,成本很高。而根据工作区的实际情况利用渔船改装的动态定位船操作简单,且费用低廉,被海洋工作者广泛采用。本文介绍了旁侧声呐在海底障碍物探测中的应用和渔船改装的GPS动态定位船进行水上定位的工作原理和施工方法。装备GPS导航软件的渔船可以指示船只的实时位置。通过改变锚绳长度来改变船只位置的动态定位技术适用于水下搜寻和探摸处理工作。  相似文献   

The REBENT monitoring network, a spatially integrated, acoustic approach to surveying nearshore macrobenthic habitats: application to the Bay of Concarneau (South Brittany, France)     

Ehrhold  Axel; Hamon  Dominique; Guillaumont  Brigitte 《ICES Journal of Marine Science》2006,63(9):1604-1615

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Temporal sampling of backscattered sonar signals     

Jaffe  Jules S. 《ICES Journal of Marine Science》1996,53(2):359-361

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Lava morphology mapping by expert system classification of high-resolution side-scan sonar imagery from the East Pacific Rise, 9°–10°N     

Jason D. Meyer  Scott M. White 《Marine Geophysical Researches》2007,28(2):81-93

Fine-scale lava morphology has been classified on the ridge crest of the East Pacific Rise between 9°15′N and 10°02′N using an expert system classification method. This method establishes the means to classify complicated seafloor environments by integrating textural and geometric feature attributes from a high-resolution side-scan sonar dataset where ground-reference data are available from near-bottom visual observations. The classification in this study focuses upon mapping the lava morphology distribution of sheet, lobate, and pillow flows along the East Pacific Rise. The reliability of the classification has been evaluated using an accuracy assessment. The study region yields a coverage area of 37,814 m² (44%) for lobate flows; 10,421 m² (12%) for pillow flows; 15,096 m² (18%) for sheet flows; 19,679 m² (23%) for fissured areas; and 2,967 m² (3%) for shadows or no data. The systematic distribution of lava morphology along the ridge found in this study supports the idea of using the regional distribution of surface morphology as an indicator of emplacement dynamics and supports an organization of the volcanic plumbing system at a third order segmentation scale beneath mid-ocean ridges.  相似文献   

Improved mapping of schooling fish near the surface: comparison of abundance estimates obtained by sonar and echo integration     

Misund  Ole Arve; Aglen  Asgeir; Hamre  Johannes; Ona  Egil; Rottingen  Ingolf; Skagen  Dankert; Valdemarsen  John Willy 《ICES Journal of Marine Science》1996,53(2):383-388

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Backarc spreading,rifting, and microplate rotation,between transform faults in the Manus Basin   总被引：2，自引：0，他引：2  

Fernando Martinez  Brian Taylor 《Marine Geophysical Researches》1996,18(2-4):203-224

The Manus Basin in the eastern Bismarck Sea is a fastopening backarc basin behind the New Britain arc-trench system. Within the basin, motion between the Pacific and Bismarck plates about a pole located at 11° S, 145° E, occurs along three major leftlateral transform faults and a variety of extensional segments. We interpret SeaMARC II sidescan and other geophysical data to show that a Brunhes age plate reorganization created new extensional boundaries and a microplate between the NW-trending Willaumez, Djaul, and Weitin transforms. Two linked spreading segments formed in backarc basin crust between the Willaumez and Djaul transforms: the ESE-trending extensional transform zone (ETZ) in the west and the Manus spreading center (MSC) in the east. Positively magnetized crust on the MSC forms a wedge varying in width from 72 km at its southwest end to zero at its northeast tip, with corresponding Brunhes spreading rates varying from 92 mm/yr to zero. The MSC forms the northwestern boundary of the 100 km-scale Manus microplate and opens at 51°/m.y. about a pole near its apex at 3°02S, 150°32E. Opposite the MSC, bordering the arc margin of New Britain, the microplate is bound by a zone of broadly distributed strike slip motion, extension, and volcanism. Within this area, the Southern Rifts contain a series of grabens partially floored by lava flows. Left-lateral motion between the Pacific and Bismarck plates appears to drive the counterclockwise pivoting motion of the Manus microplate and the complementary wedge-like opening of the MSC and the Southern Rifts. The pivoting motion of the microplate has resulted in compressional areas along its NE and SW boundaries with the Pacific and Bismarck plates respectively. East of the microplate, between the Djaul and Weitin transforms and within the arc margin of New Ireland, another zone of broad extension referred to as the Southeast Rifts takes up opening in a pull-apart basin. There, en echelon volcanic ridges may be the precursors of spreading segments, but erupted lavas include calcalkaline volcanics. Kinematic modeling and marine geophysical observations indicate that the responses to similar amounts of extension in the eastern Manus Basin have varied as a function of the different types of pre-existing crust: arc crust tectonically stretched over a broad area whereas backarc crust underwent relatively little stretching before accommodating extension by seafloor spreading.  相似文献   

Analysis of vessel influence on spatial behaviour of fish schools using a multi-beam sonar and consequences for biomass estimates by echo-sounder     

Soria  Marc; Freon  Pierre; Gerlotto  Francois 《ICES Journal of Marine Science》1996,53(2):453-458

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Relationships between the geometric dimensions and biomass of schools   总被引：1，自引：1，他引：1  

Misund  Ole Arve; Aglen  Asgeir; Beltestad  Arvid K.; Dalen  John 《ICES Journal of Marine Science》1992,49(3):305-315

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Accretionary processes in the axial valley of the Mid-Atlantic Ridge 27° N–30° N from TOBI side-scan sonar images     

Briais  Anne  Sloan  Heather  Parson  Lindsay M.  Murton  Bramley J. 《Marine Geophysical Researches》2000,21(1-2):87-119

We analyse TOBI side-scan sonar images collected during Charles Darwin cruise CD76 in the axial valley of the Mid-Atlantic Ridge (MAR) between 27°N and 30°N (Atlantis Transform Fault). Mosaics of the two side-scan sonar swaths provide a continuous image of the axial valley and the inner valley walls along more than six second-order segments of the MAR. Tectonic and volcanic analyses reveal a high-degree intra-segment and inter-segment variability. We distinguish three types of volcanic morphologies: hummocky volcanoes or volcanic ridges, smooth, flat-topped volcanoes, and lava flows. We observe that the variations in the tectonics from one segment to another are associated with variations in the distribution of the volcanic morphologies. Some segments have more smooth volcanoes near their ends and in the discontinuities than near their mid-point, and large, hummocky axial volcanic ridges. Their tectonic deformation is usually limited to the edges of the axial valley near the inner valley walls. Other segments have smooth volcanoes distributed along their length, small axial volcanic ridges, and their axial valley floor is affected by numerous faults and fissures. We propose a model of volcano-tectonic cycles in which smooth volcanoes and lava flows are built during phases of high magmatic flux. Hummocky volcanic ridges are constructed more progressively, by extraction of magma from pockets located preferentially beneath the centre of the segments, during phases of low magma input. These cycles might result from pulses in melt migration from the mantle. Melt arrival would lead to the rapid emplacement of smooth-textured volcanic terrains, and would leave magma pockets, mostly beneath the centre of the segments where most melt is produced. During the end of the volcanic cycle magma would be extracted from these reservoirs through dikes with a low magma pressure, building hummocky volcanic ridges at low effusion rates. In extreme cases, this volcanic phase would be followed by amagmatic extension until a new magma pulse arrives from the mantle.  相似文献   

An evolving ridge system around the Indian Ocean triple junction     

N. C. Mitchell 《Marine Geophysical Researches》1991,13(3):173-201

A 2°×2° map of spreading centres and fracture zones surrounding the Indian Ocean RRR triple junction, at 25.5°S, 70°E, is described from a data set of GLORIA side-scan sonar images, bathymetry, magnetic and gravity anomalies. The GLORIA images show a pervasive fabric due to linear abyssal hills oriented parallel to the two medium-spreading ridges (the Central Indian Ridge (CIR) and Southeast Indian Ridge (SEIR)). A cuvature of the fabric occurs along fracture zones, which are also located by lows in the bathymetry and gravity data and by offsets between magnetic anomalies. The magnetic anomalies also record periods of asymmetric spreading marking the development of the fracture zones, including the birth, at anomaly 2A, of a short fracture zone 50 km north of the triple junction on the CIR, and its death near the time of the Jaramillo anomaly. In some localities, a fine-scale fabric corresponds to a coarser fabric on the opposite flank of the CIR, possibly indicating a persistent asymmetry in the faulting at the median valley walls if the fabric has a tectonic and not a volcanic origin. A plate velocity analysis of the triple junction shows that both the CIR and Southwest Indian Ridge (SWIR) are propagating obliquely; the CIR appears to form an oblique trend by segmenting into a series of almost normally-oriented segments separated by short-offset fracture zones. For the last 4 m.y., the abyssal hill lineations indicate that the CIR segment immediately north of the triple junction has been spreading with an average 10° obliquity. The present small 5 km offset of the centres of the CIR and SEIR median valleys (Munschy and Schlich, 1989) is shown to be the result of this obliquity and a 30% spreading asymmetry between anomaly 2 and the Jaramillo on the CIR segment immediately north of the triple junction.  相似文献