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881.
882.
Shigeru Aoki Kazuo Shibuya Akihiro Masuyama Taku Ozawa Koichiro Doi 《Journal of Oceanography》2002,58(3):519-523
Global Positioning System (GPS) measurements of the vertical displacement of fast ice near Syowa Station, Antarctica, were
conducted between April and December 1998 to evaluate measurements of sea level variation derived with a conventional bottom
pressure gauge (BPG). The BPG-derived sea level revealed a seasonal variation of about 0.13 m, with a high in April–June and
a low in November–December. The GPS-derived sea level, combined with observed sea ice thickness, supported the BPG result,
with an RMS error of 0.007 m. Our result also demonstrates that GPS is a powerful technique for monitoring sea level variations.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
883.
Surface waves generated by a moving ship in water of finite depth are affected by the rheological properties of the movable bottom. The aim of this work is to evaluate the wave resistance exerted on a hovercraft modeled as a two-dimensional pressure distribution moving on the free surface of water with nonrigid bottom. Analysis of three-dimensional flows in two-fluid layers of finite depths is performed by assuming an inviscid upper layer (water) and a viscous lower layer (nonrigid bottom). Numerical calculations show that the maximum wave resistance occurs in the vicinity of the critical Froude number F=1. This maximum value decreases as the muddy bottom becomes less rigid. 相似文献
884.
Jeong?Hwan?LeeEmail author Young?Soon?Baek Byong?Jae?Ryu Michael?Riedel Roy?D.?Hyndman 《Marine Geophysical Researches》2005,26(1):51-59
Recently, several countries have conducted projects to explore and develop natural gas hydrate, which is one of the new alternative
energy resources for the future. In Korea, a five-year national research project was initiated in 2000. As part of this project,
a seismic survey was performed in the East Sea of Korea to quantify the potential magnitude and distribution of natural gas
hydrates. Multi-channel seismic data and core samples have been acquired and recovered in the survey area. Analysis of seismic
data show clear bottom simulating reflectors (BSRs), seismic blank zones (or wipe-out zones) with velocity pull-up structure,
and pock-marks. In this study, we present the results of seismic surveys which indicate the existence of natural gas hydrates
in Korean offshore areas. These results will be applied to select areas for coring (or drilling) and detailed exploration
such as 2D seismic survey with long offset or 3D seismic in the future. 相似文献
885.
东海沿岸潮致上升流的数值模拟 总被引:3,自引:0,他引:3
卫星照片显示东海沿岸存在一条狭长的低温水带,这是上升流将外海深层低温海水带到近岸表层所造成的现象。本文从潮汐因素探讨上升流产生的原因。对东海沿岸海域M2分潮进行三维潮流数值计算,得出的各层水平余流和垂直余流表明,由于潮汐非线性效应和海底地形的影响,能够在中国东海沿岸产生一条狭长的上升流带。此结果与卫星照片显示的海面低温水域的范围基本一致。此外还计算了在不同风速、风向作用下产生的风生上升流,并与潮致上升流进行了比较 相似文献
886.
Zhang Furan Wang Huaren Zhao Jun Assistant Researcher Tianjin Research Institute of Water Transport Engineering Tianjin Assistant Engineer Tianjin Research Institute of Water Transport Engineering Tianjin 《中国海洋工程》1992,(4)
In this paper, the effect of waves on erosion of the sandy bottom before mound breakwaters is studied. The sandy bottom basically presents two erosion patterns, between which there is a transitional state, under the action of partially standing waves. The two erosion patterns can be determined by dimensionless parameter Us, defined in this paper. The erosion locations, depths and lengths can be estimated by a series of equations presented in the text. Irregular waves are employed in the test besides regular waves, and the effect of the irregular waves can be estimated by the element of equivalent waves, such as T1/3, H1/3. 相似文献
887.
Year-to-year variation of bottom cold waters around the Korea Strait was investigated based on bottom temperatures measured
by submarine telephone cable between Pusan, Korea and Hamada, Japan from 1982 to 1992. The characteristics of bottom temperatures
could be divided into three different groups: the Korean side, the middle, and the Japanese side. Temperature drops in summer
appeared in all the three regions implying the intrusion of cold waters into the Korea Strait. Significant decreases in the
Korean side were observed in 1983, 1986, 1990, 1991, and 1992 when bottom temperatures were high in the middle. In contrast,
bottom temperatures significantly decreased in the middle in 1985, 1988, and 1989 when the temperature drops in the Korean
side were relatively small. This tendency for a negative relationship was also shown in the second mode of an EOF analysis.
In the years when bottom temperatures significantly decreased in the Korean side, the cold water along the east coast of Korea
expanded offshore and its temperature was low. On the contrary, cold water in the southern region of the Ulleung Basin developed
in the years when bottom temperatures decreased considerably in the middle. 相似文献
888.
由于埕岛油田近岸区井场地质条件复杂 ,要求坐底式平台每一次就位作业时 ,必须进行抛砂平整 ,从而导致地层土力学性质变化 ,并对下一次坐底式平台安全就位产生影响。以 CB1 5 1井场的典型资料为例 ,介绍了近岸海域井场的一般地形、地貌特征及工程地质条件差异 ,通过对坐底式平台基础沉降的分析 ,计算了坐底区、抛砂区、正常 (自然 )区 3种类型海底在外界因素作用下可能发生的沉陷量 ,总结了该类井场的一般特点 ,并对今后的坐底式平台就位作业提出了措施与建议 相似文献
889.
890.
运用海洋声传播二维 PE算法对不规则海底边界条件的处理 ,作者提出 1种改进方法 ,即利用抛物方程和界面边界条件 ,对界面附近的抛物方程的差分形式进行修正 ,以考虑复杂海底边界的影响。通过实际的数值计算表明 ,运用该方法计算声场 ,在提高计算精度方面起到有益的作用。 相似文献