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121.
A preliminary study of carbon system in the East China Sea 总被引:1,自引:0,他引:1
Shizuo Tsunogai Shuichi Watanabe Junya Nakamura Tsuneo Ono Tetsuro Sato 《Journal of Oceanography》1997,53(1):9-17
In the central part of the East China Sea, the activity of CO2 in the surface water and total carbonate, pH and alkalinity in the water column were determined in winter and autumn of 1993.
The activity of CO2 in the continental shelf water was about 50 ppm lower than that of surface air. This decrease corresponds to the absorption
of about 40 gC/m2/yr of atmospheric CO2 in the coastal zone or 1 GtC/yr in the global continental shelf, if this rate is applicable to entire coastal seas. The normalized
total carbonate contents were higher in the water near the coast and near the bottom. This increase toward the bottom may
be due to the organic matter deposited on the bottom. This conclusion is supported by the distribution of pH. The normalized
alkalinity distribution also showed higher values in the near-coast water, but in the surface water, indicating the supply
of bicarbonate from river water. The residence time of the East China Sea water, including the Yellow Sea water, has been
calculated to be about 0.8 yr from the excess alkalinity and the alkalinity input. Using this residence time and the excess
carbonate, we can estimate that the amount of dissolved carbonate transported from the coastal zone to the oceanic basin is
about 70 gC/m2/yr or 2 GtC/yr/area-of-global-continental-shelf. This also means that the rivers transport carbon to the oceans at a rate
of 30 gC/m2/yr of the coastal sea or 0.8 GtC/yr/ area-of-global shelf, the carbon consisting of dissolved inorganic carbonate and terrestrial
organic carbon decomposed on the continental shelf. 相似文献
122.
A Preliminary Study of Shear Wave in Seafloor Surface Sediments 总被引:1,自引:0,他引:1
This article preliminarily reports and analyses the transmission characteristics and behaviors of shear wave in the offshore seafloor surface sediments in China, discusses the relationships between the physical and mechanical features of the shear wave and the compression wave, and compares the testing results with that of Hamilton and Chen et al. The result shows that the shear wave can be tested if the seafloor surface sediment has tangent modulus. The shear wave velocity ranges from 50-600 m/s and the measuring frequency from 50-200 kHz. The sound velocity rate of shear wave and compression wave can be used to appraise the stress-strain feature of seafloor surface sediments. This study provides a basis for further describing and appraising the seafloor sedimentary acoustic-mechanical feature and building a geological-acoustic model on China's offshore sea area. 相似文献
123.
124.
Lynne D. Talley Pavel Tishchenko Vladimir Luchin Alexander Nedashkovskiy Sergey Sagalaev Dong-Jin Kang Mark Warner Dong-Ha Min 《Progress in Oceanography》2004,61(2-4):277
Hydrographic properties from CTD and discrete bottle sample profiles covering the Japan (East) Sea in summer, 1999, are presented in vertical sections, maps at standard depths, maps on isopycnal surfaces, and as property–property distributions. This data set covers most of the Sea with the exception of the western boundary region and northern Tatar Strait, and includes nutrients, pH, alkalinity, and chlorofluorocarbons, as well as the usual temperature, salinity, and oxygen observations. 相似文献
125.
Wave run-up, and flow visualization experiments were conducted with a 1:2 sloped sea wall model. The visualization experiments gave an overview of flow fields in reflected, non-breaking conditions. Maximum particle velocities were found to be significantly smaller than suggested in the literature. Downrush produced a fast sheet flow, extending down to the toe of the sea wall. This created a ‘reverse’ breaker during the retreat of the initially non-breaking wave, which explains the high-energy dissipation rates for non-breaking waves reported in the literature. Embankments may therefore be exposed to wave impact pressures in areas up to 1.18H0 below MWL. 相似文献
126.
The global community's ability to assess the environmental effects of marine scientific research (MSR) as required by the 1982 United Nations Convention on the Law of the Sea's (UNCLOS) marine environment provisions (MEP) is limited, as shown by experimental activities that intentionally manipulate the marine environment. Such work enhances knowledge of the ocean, but it may also have significant environmental effects. This growing use of the ocean as a laboratory has global scientific, environmental, legal and policy implications. Examined here is the relationship between the MSR and the MEP provisions of UNCLOS. International, science-driven guidelines are proposed. 相似文献
127.
风力对内陆浅水水域磷水平的影响 总被引:1,自引:0,他引:1
本文通过对平度市大泽山水库(面积约0.5平方公里,平均水深约1.5米)的实地观测,研究了风力对内陆浅水水域磷水平的影响。结果表明,影响程度取决于风速、风力作用时间、水深以及风力作用前磷水平的高低等因素。就大泽山水库而言,风速大于2.5米/秒的风力可引起各种形态磷的明显增加。不过对磷酸盐磷来说,如果浓度本来就较高,风力作用下当有大量沉积物颗粒泛起时,会对PO_4~≡产生吸附,因而可能导致水中游离磷酸盐磷含量下降。鉴于此,作者建议对内陆浅水水域进行磷水平调查时应考虑风力的作用。 相似文献
128.
Comparison among four kinds of data of sea surface wind stress in the South China Sea 总被引:1,自引:0,他引:1
By using remote sensing (ERS) data, FSU data, COADS data and Hellerman & Rosen-stein objective analysis data to analyze the sea surface wind stress in the South China Sea, it is found that the remote sensing data have higher resolution and more reasonable values. Therefore we suggest that remote sensing data be chosen in the study of climatological features of sea surface wind stress and its seasonal variability in the South China Sea, especially in the study of small and middle scale eddies. 相似文献
129.
桩式离岸堤保滩促淤工程消浪效果试验研究 总被引:9,自引:0,他引:9
在上海奉贤南北港保滩促淤工程中,采用了一种新型结构型式-桩式离岸堤,并通过物理模式试验进行了桩式离岸堤消浪效果研究。针对离岸堤通常建于近岸水区破波带的特点,重点研究水深,堤高以及堤身结构对波浪衰减的影响,同时对桩式离岸堤堤后水域的波浪底流速 分析探讨。研究结果表明,桩式离岸堤不仅具有良好的消浪效果。而且可在较大范围内改变波态,即由引起水体剧烈紊动的破波转变为浅水推进波,从而有效地改善海滩上的动力条件,促进海滩免受侵蚀,是一种具有广泛应用前景和新型保滩促淤结构。 相似文献
130.
杜勇 《中国海洋大学学报(自然科学版)》1989,(3)
作者采用非线性潮波方程,假定河口的宽度B(x)和深度h(x)是任意可微函数,导出了涌潮发生的条件,并讨论了各种变形情况下涌潮的形成。得出结论是,在涌潮形成过程中起决定作用的是浅水非线性效应,而河口变形效应则是起促进作用的。 相似文献