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排序方式: 共有7247条查询结果,搜索用时 31 毫秒
31.
Jean-Marie Auzende Eiichi Honza Xavier Boespflug Satendra Deo Jean-Philippe Eissen Jun Hashimoto Philippe Huchon Junichiro Ishibashi Yo Iwabuchi Philip Jarvis Masato Joshima Kiyoyuki Kisimoto Yasuto Kuwahara Yves Lafoy Tsuyoshi Matsumoto Jean-Pierre Maze Kiyohiko Mitsuzawa Hiroyasu Monma Takeshi Naganuma Yukihiro Nojiri Suguru Ohta Kiyoshi Otsuka Yoshihisa Okuda Hélène Ondreas Akira Otsuki Etienne Ruellan Myriam Sibuet Manabu Tanahashi Takeo Tanaka Tetsuro Urabe 《Marine Geophysical Researches》1990,12(4):269-283
The aim of the Japanese-French Kaiyo 87 cruise was the study of the spreading axis in the North Fiji Basin (SW Pacific). A
Seabeam and geophysical survey allowed us to define the detailed structure of the active NS spreading axis between 16° and
22° S and its relationships with the left lateral motion of the North Fiji Fracture Zone. Between 21° S and 18°10′ S, the
spreading axis trends NS. From 18°10 S to 16°40 S the orientation of the spreading axis changes from NS to 015°. North of
16°40′ S the spreading axis trends 160°. These two 015° and 160° branches converge with the left lateral North Fiji fracture
zone around 16°40′ S to define an RRFZ triple junction. Water sampling, dredging and photo TV deep towing give new information
concerning the hydrothermal activity along the spreading axis. The discovery of hydrothermal deposits associated with living
communities confirms this activity. 相似文献
32.
High precision geoid models HKGEOID-2000 for Hong Kong and SZGEOID-2000 for Shenzhen, China, have been developed with a hybrid approach of so-called sequential processing, using high precision GPS/leveling data, land and sea gravity anomalies, and digital terrain models. These two local geoid models have the same 1-km resolution. The estimated accuracy (external accuracy) is better than 1.7 cm for HKGEOID-2000 and 1.4 cm for SZGEOID-2000. Some common areas are covered by HKGEOID-2000 and SZGEOID-2000. So these two geoid models, along with high quality GPS/leveling data collected on the overlapping areas, can be used to detect the systematic bias between HKGEOID-2000 and SZGEOID-2000, as well as the difference between Hong Kong Principal Datum and 1956 yellow sea height datum of China, yielding RMS errors of 1.011 m and 1,003 m, respectively. Moreover, HKGEOID-2000, along with GPS ellipsoidal heights, is employed to determine the errors of the “orthometric heights” from purely trigonometric heighting, yielding an RMS error of 0.102 m. The combination of SZGEOID-2000 and GPS ellipsoidal heights has been used to replace the traditional spirit leveling and mapping, called GPS mapping. 相似文献
33.
利用RAPD和AFLP标记 ,以一回交家系 [(Miyagi×Hiroshima)×Miyagi]为作图群体 ,构建了太平洋牡蛎的遗传连锁图谱。用经过筛选的 3 3个RAPD引物和 1 1个AFLP引物组合 ,对父母本和 80个子代个体进行了遗传分析。共得到母本分离标记 1 93个 ,其中 1 44个符合1∶1孟德尔分离规律。父本分离标记 1 5 6个 ,其中 1 1 1个符合 1∶1孟德尔分离规律。雌性框架图包括 99个遗传标记 ,定位在 1 2个连锁群中 ,覆盖 985 2cM ,标记间平均间隔 1 1 3cM。另外有 3个三联体 ,7个连锁对 ,图谱共覆盖 1 1 6 5 7cM。雄性框架图包括 72个遗传标记 ,分布在 8个连锁群 ,覆盖 81 1cM ,标记间平均间隔 1 2 7cM。另外有 4个三联体 ,3个连锁对 ,图谱共覆盖93 1 8cM。 相似文献
34.
南黄海表层沉积物中氮的区域地球化学特征 总被引:5,自引:0,他引:5
通过分级浸取分离的方法获得了南黄海表层沉积物不同形态的氮,首次探讨其分布的区域性特征:南黄海表层沉积物中各形态氮在不同测线上均呈现出波状分布。B测线的基本上呈现出中部海域高,两边海域低,而西部海域又略高于东部海域的趋势,D和E测线的基本上呈现出西高、东低的趋势,C测线的则呈现出西低、东高的趋势,F测线的变化趋势比较平缓,从整体上看,SOEF—N和TN的分布呈现出西部海区比东部海区低的趋势。受各测线上沉积物种类差异的影响,自北向南各形态氮的变化幅度逐渐减小,其中SOEF-N在各测线上的变化幅度最大,且自北向南降幅最大。受水动力及沉积物粒度的影响,不同形态氮在黄海槽内各站位沉积物中的含量较高。沉积物中各形态氮在不同测线上的分布还表明,陆源输入对南黄海沉积物中氮测线分布有较小的影响,海洋自生氮对南黄海表层沉积物中氮的形态、含量与分布具有重要影响。 相似文献
35.
J. Acosta E. Uchupi A. Muñoz P. Herranz C. Palomo M. Ballesteros 《Marine Geophysical Researches》2003,24(1-2):41-57
Circular to elliptical mounds in the Canary Channel with reliefs of 75 to 375 m and diameters of 4 to 8 km partially surrounded by moats with reliefs of 25 to 75 m, were formed by piercement of the seafloor by Mesozoic evaporites. Several long gullies, < 1km wide, with abrupt terminations and pockmarks associated with these mounds were probably eroded by dense brine and hydrocarbon seeps. The salt brines that eroded the gullies were formed where salt diapirs intersect the seafloor, or in the subsurface by circulating ground water heated by igneous activity along the Canary Ridge. If the brines originated in the subsurface they reached the seafloor along faults. Displacement of the surficial sediments by sliding and creep is probably the result of the expulsion of hydrocarbons and/or vertical motion of the Mesozoic evaporites. Microtopographic features along or near the east flank of the Canary Ridge are the creation of uplift of the ridge, hydrothermal activity, mass wasting processes and turbidity currents. 相似文献
36.
37.
John K. Hall 《Marine Geophysical Researches》2006,27(1):1-5
This special issue of Marine Geophysical Researches presents five papers dealing with GEBCO, the General Bathymetric Chart
of the Oceans, which celebrated its Centennial in April 2003, hosted by the International Hydrographic Bureau and the Principality
of Monaco. Over the past 103 years GEBCO has been the sole body dedicated to compiling all available data to produce standardized
maps of the oceans and seas covering 71% of planet Earth. Over time GEBCO has undergone a complete transformation as sparse
500 m contours on paper charts were replaced by digital grids with ever-increasing resolution. The 2003 Centennial saw the
release on two CDROMS with the first global 1′ grid, produced by methods unheard of in 1984, when GEBCO’s last 6th Edition
paper chart set was published. In GEBCO’s second century, the thrust is towards global grids that will capture the resolutions
available with evolving deep-water swath mapping technologies, as well as vast improvement in the details of the shallow continental
shelves that have traditionally been the preserve of the hydrographic community. As little more than 10% of the oceans have
been mapped to the desired level of detail, there is much to be done. However refinements in satellite altimetry appear to
offer an interim stop-gap as more multi-beam sonars ply the oceans and as the littoral countries of the world map their adjacent
marine areas for submission under Article 76 of UNCLOS (United Nations, 1983, 1999). In addition GEBCO is becoming increasingly proactive, with outreach to the public via the internet and a new GEBCO Map
of the World, active data-scrounging, and encouraging development of the first drifting buoys for acquiring data in the inaccessible
areas of the Antarctic, SW Pacific, and Arctic Oceans. 相似文献
38.
The distribution and geochemical composition of suspended-particulate matter (SPM) in the East China Sea (ECS) were investigated
during the summer period of high continental runoff to elucidate SPM sources, distribution and cross-shelf transport. The
spatial variability of SPM distribution (0.3–6.5 mg l−1) and geochemical composition (POC, Al, Si, Fe, Mn, Ca, Mg and K) in the ECS was pronounced during summer when the continental
fluxes of freshwater and terrestrial materials were highest during the year. Under the influences of Changjiang runoff, Kuroshio
intrusion, surface production and bottom resuspension, the distribution generally showed strong gradients decreasing seaward
for both biogenic and lithogenic materials. Particulate organic carbon was enriched in surface water (mean ∼18%) due to the
influence of biological productivity, and was diluted by resuspended and/or laterally-transported materials in bottom water
(mean 9.4%). The abundance of lithogenic elements (Al, Si, Fe, Mn) increased toward the bottom, and the distribution correlations
were highly significant. Particulate CaCO3 distribution provided evidence that the SPM of the bottom water in the northern part of the study area was likely mixed with
sediments originally derived from Huanghe. A distinct benthic nepheloid layer (BNL) was present in all seaward transects of
the ECS shelf. Sediment resuspension may be caused by tidal fluctuation and other forcing and be regarded as the principal
agent in the formation of BNL. This BNL was likely responsible for the transport of biogenic and lithogenic particles across
or along the ECS shelf. Total inventories of SPM, POC and PN are 46, 2.8 and 0.4 Tg, respectively, measured over the total
area of 0.45 × 106 km2 of the ECS shelf. Their mean residence times are about 27, 13 and 11 days, respectively. The inventory of SPM in the water
column was higher in the northernmost and southernmost transects and lower in the middle transects, reflecting the influences
of terrestrial inputs from Changjiang and/or resuspended materials from Huanghe deposits in the north and perhaps from Minjiang
and/or Taiwan’s rivers in the south. The distribution and transport patterns of SPM and geochemical elements strongly indicate
that continental sources and cross-shelf transport modulate ECS particulate matter in summer. 相似文献
39.
40.
The added mass of hull section shapes must be known, in order to carry out any studies of ship motions, which may be associated with either seakeeping or manoeuvring. Determination of the added mass in deep water can involve conformal mapping or surface singularity distributions. However, in shallow water the problem of determining the added mass is made more difficult by the proximity of the seabed. In this paper, three approaches to the problem of finding the added mass of semi-circular sections are explored. Although there is no known exact solution to this problem, the relationships given by the three methods are compared and the approximate nature of the solutions is examined. The first method is a series solution, which is taken here to include more terms than are normally given in the existing literature. The other two solutions are considered to be new, and so are given in some mathematical detail. 相似文献