湄洲湾潮流数值计算     

孙长青  赵可胜  郭耀同 《海洋科学》2004,28(12):35-38

采用不规则三角形网格的分步杂交法，建立了湄洲湾海域二维变动边界潮流数值模型，通过计算得到最大潮流分布、同潮时线与等振幅线、潮流椭圆、潮致欧拉余流分布及不同时刻潮流场分布。  相似文献   

Undular tidal bore dynamics in the Daly Estuary, Northern Australia   总被引：7，自引：0，他引：7  

Eric Wolanski  David Williams  Simon Spagnol  Hubert Chanson 《Estuarine, Coastal and Shelf Science》2004,60(4):629-636

Measurements in the macro-tidal Daly Estuary show that the presence of an undular tidal bore contributed negligibly to the dissipation of tidal energy. No recirculation bubble was observed between a trough and the following wave crest in the lee waves following the undular bore. This differs to stationary undular bores in laboratory experiments at larger Froude numbers where a recirculation bubble exists. Secondary motions and the turbulence generated by the undular bore had no measurable influence on the sediment transport. This situation contrasts with the intense sediment resuspension observed in breaking tidal bores. The tidally averaged sediment budget in the Daly Estuary was controlled by the asymmetry of tidal currents. The undular bore may widen the river by breaking along the banks that it undercuts, leading to bank slippage. A patch of river-wide macro-turbulence of 3-min duration occurred about 20 min after the passage of the bore during accelerating tidal currents.  相似文献   

大连湾海流分布特征的探讨     

刘恒魁 《海洋科学》1990,14(6):23-27

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Benthic photosynthesis in submerged Wadden Sea intertidal flats   总被引：3，自引：1，他引：3  

Markus Billerbeck  Hans Ry  Katja Bosselmann  Markus Huettel 《Estuarine, Coastal and Shelf Science》2007,71(3-4):704-716

In this study we compare benthic photosynthesis during inundation in coarse sand, fine sand, and mixed sediment (sand/mud) intertidal flats in the German Wadden Sea. In situ determinations of oxygen-, DIC- and nutrient fluxes in stirred benthic chamber incubations were combined with measurements of sedimentary chlorophyll, incident light intensity at the sediment surface and scalar irradiance within the sediment. During submergence, microphytobenthos was light limited at all study sites as indicated by rapid response of gross photosynthesis to increasing incident light at the sea floor. However, depth integrated scalar irradiance was 2 to 3 times higher in the sands than in the mud. Consequently, gross photosynthesis in the net autotrophic fine sand and coarse sand flats during inundation was on average 4 and 11 times higher than in the net heterotrophic mud flat, despite higher total chlorophyll concentration in mud. Benthic photosynthesis may be enhanced in intertidal sands during inundation due to: (1) higher light availability to the microphytobenthos in the sands compared to muds, (2) more efficient transport of photosynthesis-limiting solutes to the microalgae with pore water flows in the permeable sands, and (3) more active metabolic state and different life strategies of microphytobenthos inhabiting sands.  相似文献   

长江口滨岸潮滩柱样沉积物与孔隙水中氮的垂直分布特征   总被引：3，自引：1，他引：3  

刘巧梅  刘敏  许世远  侯立军  欧冬妮 《海洋科学》2004,28(9):13-19

对长江口滨岸潮滩柱样沉积物及孔隙水中NH4^ -N、NO3^--N和NO2^--N的剖面进行了分析。结果表明，沉积物和孔隙水中NH4^ -N，NO3^--N和NO2^--N剖面分布基本一致，其中NH4^ -N含量最高，这说明有机质的降解反应主要是在缺氧或无氧环境中进行的；沉积物中有机质含量与NH4^ -N含量线性相关；NO3^--N和NO2^--N在剖面中以0～20cm变化剧烈，说明表层和深层有机质的降解程度发生改变。  相似文献   

黄河三角洲潮滩剖面特征   总被引：4，自引：0，他引：4  

周良勇  李广雪  刘健  李安龙  邓声贵  温国义  赵东波 《海洋地质与第四纪地质》2006,26(2):1-8

利用验潮、潮滩水准测量、沉积物分析和遥感资料,分析了黄河三角洲不同岸段潮滩的特征。水准测量表明,侵蚀潮滩剖面形态为下凹,而淤积潮滩则上凸,由高潮线至低潮线,潮滩沉积物均变粗,这种变粗趋势在北部侵蚀岸段和河口侧缘明显,在河口南侧稳定海岸则不明显。潮滩沉积物含水量为12.2%~32.2%,平均为21%,海滩表层沉积物不排水剪切强度在0.1~0.35 kg/cm2之间。受局限岸滩的平面形态和剖面形态受到周围大坝地形影响,具有和砂质海滩类似的形态,显示波浪对该潮滩的作用强烈,根据剖面测量结果与遥感图像,发现河口北侧有一个小的冲积扇。  相似文献   

春夏季南黄海西部沿岸低盐水入侵温跃层现象的研究   总被引：2，自引：1，他引：2  

周锋  苏纪兰  黄大吉 《海洋学报》2004,26(5):34-44

2000年6月至2002年6月春夏季期间,在南黄海春夏季南黄海西部沿岸低盐水入侵温跃层现象的研究鱼产卵场进行了4个航次的多学科调查,海洋水文观测分析结果表明:在苏北浅滩外侧、成山头—石岛外侧的层化海区的温跃层中存在低盐水现象.春夏增温季节温跃层加强,低盐水入侵现象逐渐增强;入侵强度也存在年际变化.苏北浅滩入侵低盐水舌向北偏东方向延伸,水舌较宽,入侵较远;石岛附近入侵低盐水舌向南偏西方向延伸,水舌较窄,入侵较弱.温跃层中低盐水是由于沿岸低盐水入侵造成的,并与当地的潮锋现象存在密切的关系.  相似文献   

Isotopic and Elemental Variations of Carbon and Nitrogen in a Mangrove Estuary   总被引：6，自引：0，他引：6  

L.A. Cifuentes  R.B. Coffin  L. Solorzano  W. Cardenas  J. Espinoza  R.R. Twilley 《Estuarine, Coastal and Shelf Science》1996,43(6):781-800

Variations in elemental and isotopic ratios of suspended particulate matter (SPM) were investigated in the Guayas River Estuary Ecosystem (GREE) that empties into the Gulf of Guayaquil, Ecuador. Detritus in the system was identified on the basis of extremely high carbon:chlorophyll aratios (>1000). This material had mean δ¹³C of −26·4±0·3, δ¹⁵N of +4·8±0·2, and (C:N)_atomicof 14·1±0·9. The isotopic data were comparable to measurements reported for fresh and degrading mangrove leaves, whereas the elemental ratio was comparatively enriched in nitrogen. Isotope measurements of SPM throughout the GREE were more similar to values for riverine material and detritus compared with that for the coastal end-member. Values indicative ofin situproduced algae, sewage and shrimp pond effluent were only found at selected sites. Bacterial bioassays, which were used to document potential sources of dissolved organic matter in the GREE, were isotopically similar to SPM. This correspondence coupled with the relatively low (C:N)_aof SPM could be explained by bacterial immobolization of nitrogen onto detritus. Finally, tidal variations of (C:N)_aand δ¹³C at a brackish mangrove site were similar in magnitude to spatial variations encountered throughout the GREE. Based on these results, the authors caution that care must be taken when samples are taken for food-web studies in these systems.  相似文献   

Tidal fluxes of nutrients and suspended sediments at the North Inlet–Winyah Bay National Estuarine Research Reserve     

L.R. Gardner  B. Kjerfve   《Estuarine, Coastal and Shelf Science》2006,70(4):682

Beginning June of 1993 suites of 13 water samples have been collected at Oyster Landing, North Inlet (SC), every 20 days covering two consecutive tidal cycles at 2.07 h intervals. In order to ascertain whether this large (and still growing) water chemistry data set can be used to determine tidal fluxes of nutrients and sediments, we coupled measured concentrations to estimates of instantaneous tidal discharge based on a basin water storage curve and hindcast tides. The mean advective fluxes of all constituents, including salt, showed statistically significant exports. This result, however, is largely due to an ebb bias in the sampling protocol, which resulted in 52% of the samples being collected on ebb tide versus a theoretical percentage of 48%. When this bias was corrected by reducing the mean discharge (−610 l s⁻¹) to a value (−125 l s⁻¹) that produced a balance between the mean advective and dispersive salt fluxes, the advective fluxes of the other constituents were reduced to values that are not significantly different from zero. In addition to a statistically significant dispersive influx of salt, significant dispersive exports were found for DON, NH₄, DOP, PO₄ and DOC. All particulate constituents (PN, PP, ISS and OSS) yielded dispersive fluxes that were not significantly different from zero. Annual material budgets for the Oyster Landing basin based on the dispersive fluxes of all constituents (except salt) are generally similar in magnitude and direction to those measured by [Dame, R.F., Spurrier, J.D., Williams, T.M., Kjerfve, B., Zingmark, R.G., Wolaver, T.G., Chrzanowski, T.H., McKeller, H.N., Vernberg, F.J., 1991. Annual material processing by a salt marsh-estuarine basin in South Carolina, USA. Marine Ecology Progress Series 72, 153–166.] in the nearby and ecologically similar Bly Creek basin, indicating that the dispersive fluxes determined in this study are realistic. We offer suggestions for improving the reliability and usefulness of future Oyster Landing water quality data.  相似文献   

半封闭海湾潮间带部分围垦后纳潮量计算的商榷——以胶州湾为例   总被引：14，自引：1，他引：14  

杨世伦  陈启明  朱骏  张经 《海洋科学》2003,27(8):43-47

传统的海湾(泻湖)纳潮量计算方法不能精确地反映潮间带被部分围垦后纳潮量的实际情况,本考虑围堤的影响,将纳潮量分解为堤基以下的“梯形”区和堤基以上的“矩形”区两部分之和,在理论上更加严密。根据改进后方法算出的胶州湾近期纳潮量比传统方法算出的纳潮量大15％左右。可见,半个多世纪以来胶州湾的纳潮量只减少了约15％．而不是传统方法得出的约25％。  相似文献