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1.
以秦皇岛、京唐港、曹妃甸、黄骅4个验潮站的实测潮位和逐时风的数据为基础,以2013年河北省政府发布的风暴潮四色警戒潮位值为标准,统计了2008-2017年10 a河北省沿海的风暴潮过程,从警报级别、区域分布、时间分布、天气系统、经济损失5个方面分析河北省沿海风暴潮特征,并从地形、天文潮与天气系统配合、海平面上升、全球变暖引发的气候异常4个方面分析了影响河北省沿海风暴潮的成因,分析得出:受天气系统的影响,7-10月是河北省风暴潮高发时段,且由于河北省岸线分布特点,沧州市沿海受到风暴潮影响的次数最多,唐山和秦皇岛次之,沧州和唐山地区的风暴潮过程多由东北向大风引起,而秦皇岛地区的风暴潮过程多由东南向风引起。 相似文献
2.
为定量化研究影响中国东部近海逆温层产生和发展过程的主要因素,基于Princeton Ocean Model(POM),通过进行河流和暖流的增减试验,对逆温层的季节变化及其影响因素进行了分析。模拟结果显示,受海表失热影响,逆温层主要出现在9月至翌年3月份,山东半岛北部及东部近海、闽浙沿海为三个主要逆温层发生区域,其中山东半岛北部近海逆温层范围和强度最大。当无河流输入时,整个研究海域无逆温层出现,而河流加倍或减半对逆温层的影响主要体现在长江口邻近海域,出现概率分别增高22%和降低15%。当暖流加倍或减半时,长江口邻近海域逆温层出现概率大幅增高23%和降低69%,山东半岛东部近海次之,分别增高34%和降低25%。当关闭暖流时,长江口外海逆温层消失,山东半岛东部近海逆温层出现概率降低约70%,且变浅76%。以上表明,河流淡水是中国东部近海逆温层形成的必要条件,在保持必要河流淡水输入条件下,暖流的变化对中国东部近海逆温层形成的影响比河流变化大,其中对长江口外海影响最大,山东半岛东部近海次之。暖流流量的增减可引起100 m以浅陆架区的海表面高度异常,影响跨40 m等深线海水交换和温盐锋面的形成,造成逆温层大范围的转移和变化。 相似文献
3.
《Deep Sea Research Part I: Oceanographic Research Papers》2007,54(8):1311-1328
The response of an ocean general circulation model (OGCM) to two different wind products, viz., NCEP/NCAR reanalysis and QuikSCAT scatterometer, was examined. OGCM-simulated thermodynamic variables from the two simulations, hereafter referred to as NCEP-R (NCEP/NCAR wind forced) and QS-R (QuikSCAT wind forced) were intercompared and also were compared against observations for a period of 3 years (2000–2002). In the tropical Indian Ocean (IO), the sea-level anomaly (SLA) simulated by QS-R has less root mean square error (RMSE) and higher correlation with respect to TOPEX/Poseidon SLA observations than SLA simulated by NCEP-R. Intraseasonal variability of currents observed by TRITON buoy in the IO was closely captured by QS-R, although the magnitudes are somewhat underestimated. Surface currents simulated by QS-R have less RMSE than those simulated by NCEP-R in the Pacific. However, the sub-surface currents are much weaker in magnitude in both the solutions, possibly because of deficiencies in the diffusion and viscosity parameterization. Sea-surface temperature (SST) simulated by QS-R has a cooler bias. The RMSE of SST simulated by NCEP-R is less than the RMSE of SST simulated by QS-R, with the latter capturing the variabilities more realistically. The large differences between SST simulated by QS-R and observations could be partly due to physical inconsistency between the momentum and heat fluxes. Scatterometer-forced model simulations of 20oC thermocline depths (D20) are in better agreement with in situ-derived D20 than the D20 simulated by NCEP-R. Variations in the mixed layer depth at the TRITON buoy are better captured by QS-R than by NCEP-R. Speed of Kelvin and Rossby waves and the strength of upwelling/downwelling features in the IO are closer to observations in QS-R than in NCEP-R simulations. 相似文献
4.
沉积物对磷酸盐的吸附与释放 总被引：3，自引：0，他引：3
本实验研究黄河口水文站沉积物对黄河水磷的吸附释放过程和东海１１１号站位沉积物对海水磷的吸附释放过程。并摸拟黄河沉积物在海水中磷的吸附释放过程。结果表明：底沉积物对磷的吸附相当迅速，无论是河泥还是海泥在２４ｈ内均能达到吸附平衡。吸附量与沉积物的量和水中原有磷的浓度有关，在不同的ｐＨ条件下，沉积物对磷的吸附是有显著差别的 相似文献
5.
Paz Garcia-Martinez Antal K.D. Hajos David R. Livingstone Gary W. Winston 《Marine environmental research》1992,34(1-4)
The modulation of the mutagenicity of 4-nitroquinoline N-oxide (4-NQO) by M. edulis digestive gland cytosolic and microsomal fractions was studied by monitoring the induction of the umu operon by 4-NQO in Salmonella typhimurium 1535/pSK1002. The mutagenicity of 4-NQO was increased by M. edulis cytosol and microsomes in dose-dependent manner with respect to protein and toxicant concentration. The mutagenic enhancement reflected increased NAD(P)H-dependent oxygen consumption by microsomes in the presence of 4-NQO and enhanced nitroreductase activity in cytosol. The former was stimulated by azide, indicating 4-NQO-enhanced oxyradical production by microsomes, and the latter was inhibitable by dicoumarol, indicating involvement of DT-diaphorase in nitroreduction by M. edulis cytosol. Neither dicoumarol nor allopurinol (inhibitors of DT-diaphorase and xanthine oxidase, respectively) affected the enhanced mutagenic expression of 4-NQO by cytosol. The results support the possibility of oxidative stress as a pollution-mediated mechanism of toxicity. 相似文献
6.
4种海洋绿藻光合放氢特征的研究 总被引：5，自引：0，他引：5
四爿藻(Tetraselmis sp．)、微绿球藻(Nannochloropsis occulata)、小球藻(Chlorella vulgaris)和扁藻(Ptatymonas subcordiformis)的放氢特点各不相同。在暗厌氧培养阶段,四爿藻和微绿球藻不释放氢气,小球藻和扁藻释放微量的氢气。随后的光照培养阶段中,4种海藻在天然海水中都释放氢气,四爿藻和小球藻在无硫海水中不释放氢气,而微绿球藻在无硫海水中释放的氢气比在天然海水中的少,扁藻在无硫海水中释放的氢气为天然海水中的10倍。在4种藻中。亚心型扁藻的光合放氢能力最高。解偶联剂CCCP(carbonyl cyanide m—chlorophenylhydrazone)对该4种藻的光合放氢的影响各不相同,并初步推测了扁藻光合放氢的速度限制因素。 相似文献
7.
本文推导了随机载荷下的疲劳损伤计算公式。数值计算结果表明：Ｐ．Ｈ．Ｗｉｒｓｃｈｉｎｇ给出的公式在宽带情况下与实际情况不符；Ｇ．Ｃｈａｕｄｈｕｒｙ给出的公式在窄带情况下与实际不符；本文绘出的公式不仅适合于窄带，也适合于具有各种不同带宽的宽带随机载荷。 相似文献
8.
《Ocean Engineering》2004,31(8-9):1063-1082
An analytical method is presented to analyze the radiation and diffraction of water waves by a rectangular buoy in an infinite fluid domain of finite water depth. Analytical expressions for the radiated potentials and the diffracted potentials are obtained by use of the method of separation of variables. The unknown coefficients in the expressions are determined by use of the eigenfunction expansion matching method. The added masses and damping coefficients for the buoy heaving, swaying and rolling in calm water are obtained by use of the corresponding radiated potentials. Wave excitation forces are calculated by two different approaches, one is by use of the radiated potentials through Haskind’s theorem and the other is by the diffracted potential. It can be seen that the latter approach for wave forces on a rectangular buoy is much simpler than the former. To verify the correctness of the method, two specific examples in the past references are recomputed and the obtained results are in good agreement with those by use of other methods, which shows that the present method is correct. 相似文献
9.
鱼类甲状腺轴由下丘脑、垂体、甲状腺组成,下丘脑通过分泌促甲状腺激素释放激素、促肾上腺皮质激素释放激素调节垂体促甲状腺激素的合成和分泌,促甲状腺激素促进甲状腺滤泡合成并释放甲状腺激素(主要为甲状腺素—T4),T4运输至肝脏等外周组织中,经过脱碘转化形成生物活性更强的三碘甲腺原氨酸(T3),T3主要通过同核受体结合发挥生物学功能。甲状腺激素对鱼类胚胎发育、仔鱼变态及性别分化等早期生长发育过程具有重要调控作用:甲状腺激素为鱼类胚胎发育期所必须,外加适量甲状腺激素能够提高胚胎或仔鱼存活率;仔鱼变态过程中,某些外部形态变化及相关组织分化依赖甲状腺激素的调控,牙鲆等仔鱼变态期体内甲状腺激素水平及其受体表达量会显著升高;性腺发育期,甲状腺激素对调控鱼类性别分化方向可能具有一定作用。 相似文献
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11.
南海粘土矿物组合特征及其环境意义 总被引：1，自引：0，他引：1
利用X射线衍射法(XRD)对南海12个海底表层沉积物和20个悬浮物样品中粘土矿物组成和分布特征进行了综合分析。结果表明:(1)研究区的表层沉积物粘土矿物以伊利石为主,其次为绿泥石、高岭石、伊/蒙间层矿物以及蒙皂石;悬浮物粘土矿物是以绿泥石为主,其次为高岭石、蒙皂石、伊利石以及伊/蒙间层矿物。(2)粘土矿物的组成和分布特征主要受气候条件、物质来源、水动力条件及相互间稀释作用的制约。伊利石的含量随离岸距离和水深的增加呈增大趋势;高岭石则在近岸区特别是河口区富集;绿泥石在西部沿岸海区的含量较低,在东部岛弧和北部台湾岛附近海区的含量较高;蒙皂石与火山作用密切相关,在东部火山岛弧附近海区含量较高。(3)粘土沉积物的来源以河流输入为主,海洋自生和风尘搬运对该区的沉积影响不大。(4)深海悬浮物粘土矿物的组成变化能够很好地指示短尺度气候环境的变迁,伊利石的结晶程度对气候和环境变化反映灵敏,其随所处环境的压力增大而变差。 相似文献
12.
The two-dimensional problems concerning the interaction of linear water waves with cylinders of arbitrary shape in two-layer deep water are investigated by use of the Boundary Integral Equation Method (BIEM). Simpler new expressions for the Green functions are derived, and verified by comparison of results obtained by BIEM with those by an analytical method. Examined are the radiation and scattering of linear waves by two typical configurations of cylinders in two-layer deep water. Hydrodynamic behaviors including hydrodynamic coefficients, wave forces, reflection and transmission coefficients and energies are analyzed in detail, and some interesting physical phenomena are observed. 相似文献
13.
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
14.
高频地波雷达生成海洋表面矢量流图 总被引：10，自引：0，他引：10
武汉大学研制的双站高频地波雷达系统OSMAR2000利用测得的两幅单站径向海流图生成矢量海流图。经典矢量流图生成方法不能直接应用到OSMAR2000系统中。本文提出一种先在极坐标系下用自然三次样条函数将径向流插值到公共网格上然后直接进行矢量合成的矢量海流图生成方法。OSMAR2000在东海的表面矢量流实测结果与作对比验证的传统海流计测量结果十分吻合。对比数据表明，该方法是可行的，且优于先进行径向流线性插值后矢量合成的矢量流图生成方法。这也是国内首次利用高频地波雷达实现海洋表面矢量流的实时监测。 相似文献
15.
Dou Guoren
Academician of Chinese Academy of Sciences Honorary Director of Nanjing Hydraulic Research Institute Nanjing 《中国海洋工程》1996,(1)
- Turbulent flow is a basic form of fluid motion widely observed in nature. In hydraulic engineering, especially in the study of sediment movement, turbulence is a key problem. In this paper, based on the stochastic theory of wall turbulence developed by the author and the results by other investigators, fluc-tuation and mean structures and drag coefficient for Newtonian and drag reduction flows in all states (laminar, transitional, turbulent) and in all regions (smooth, transitional, rough) are theoretically discussed in detail. General laws for laminar and turbulent flows obtained by the author are verified by the experimental results obtained by others, and there is good agreement between them. 相似文献
16.
17.
Matsumoto Takeshi Goslin Jean Lagabrielle Yves Ruellan Etienne Tanahashi Manabu 《Marine Geophysical Researches》1997,19(1):37-53
A surface ship gravity survey was carried out in the northern part of the North Fiji Basin during the NOFI cruise by the R/V l'Atalante in August-September, 1994. The two ridges inside the study area, the South Pandora Ridge and the Tripartite Ridge, present different structures and states of isostatic equilibrium in terms of gravity anomaly and its tectonic implications. The former is supported by a restoring force of an imaginary elastic plate in the crust and the latter by the Airy type isostasy. These characteristics can be derived from the difference in magmatic activity, as influenced by the difference in lithospheric structure. The latter is characterised by greater active magmatism and hydrothermalism underneath the ridge than the former. Such a difference in the magmatic activity and the horizontal scale of the shallow subsurface structure is derived from the difference in the stiffness or viscosity of the lithosphere beneath the two ridges. 相似文献
18.
《Marine Policy》2017
Comments are provided on several points in the 2016 State of the World Fisheries and Aquaculture produced by the Food and Agriculture Organization of the United Nations (FAO). It is shown that data assembled by FAO from submissions by countries suggest a “stable” trend mainly because the declining catches of a number of countries with reliable statistics is compensated for by unreliable statistics from countries where reporting increasing catches may be politically expedient, e.g., China, Myanmar. Also, concerns are raised as to why FAO chose to ignore the well-documented data ‘reconstruction’ process, which fills the gaps that exist in data reported by countries to FAO. It is being ignored despite its importance for governance and resource conservation being well known. This process and its findings could be used by FAO to encourage countries to improve their data reporting, including retroactive corrections. This is important in view of successive analyses of the status of fisheries resources undertaken by FAO (published in current and past SOFIAs) and also in modified form by the Sea Around Us. This suggests a degradation of marine fisheries, and, if trends continue, a crisis by mid-century. Finally, comments are presented on the proposition that aquaculture will overtake wild capture fisheries in terms of food production, notably because current aquaculture requires huge quantities of wild-caught fish as feed. Indeed, this emphasis on aquaculture-as-substitute for fisheries raises issues of food security and malnutrition in developing countries, from which much of the fish used as feed originates. 相似文献
19.
于1997年6月在青岛市沙子口海域采集文昌鱼样品，采用RT－PCR方法进行青岛文昌鱼LIM类同源框基因片段的扩增研究。结果表明，用一对引物一次PCR扩增的方法未能得到特异的PCR产物，用一对引物两次PCR扩增的方法也同样未果。在对套式PCR进行研究时发现，用普遍PCR方法进行的套式PCR结果不够理想，而用三步两段法和四步两段法套式PCR则可进行成功的扩增。用这两种方法扩增的PCR产物具有高度特异性。相比之下，用简并的引物对未知的基因片段进行PCR扩增时，三步两段法和四步两段法的套式PCR应是首选方法。 相似文献
20.
Locomotion is essential for vertebrate survival. Forces required for movement are generated by skeletal muscle. Skeletal muscle shortening and/or force generation occur via parallel sliding of two protein filaments: actin and myosin. This is driven by the cycling of cross-bridges, whose unitary nanometer length change and picoNewton force output are fueled by conversion of chemical energy, stored in the form of adenosine triphosphate, into a change in myosin protein configuration. The range of force and length changes of a muscle is determined by factors such as muscle cross section, fiber angle, tendon attachment, and lever geometry, but also by the metabolic pathways available for adenosine triphosphate synthesis and by enzymes involved in cross-bridge cycling. In addition, muscle mechanical activity is affected by the extent of actin and myosin filament overlap. Force output can be graded by selective recruitment of motor units and/or by variation of force output from individual units. The cost of locomotion is subject to species differences and is affected by the environment and form of movement, with an energy efficiency of up to 0.4. Overall, design principles of vertebrate skeletal muscle may serve as an interesting reference point for novel actuator technologies. 相似文献