Parameterization of Wave Breaking Probability and Whitecap Coverage     

李晶于定勇  刘华兴 《中国海洋工程》2006,20(3):411-418

1 .Introduction Wave breaking and associated whitecapping have long beeninteresting due totheir close relationto many fields of ocean study,including air-sea interaction,remote sensing,ocean engineering,aswell as wave dynamics .The breaking probabilityBan…  相似文献   

Analysis, synthesis and modelling of high-resolution observations of salt-marsh eco-geomorphological patterns in the Venice lagoon   总被引：1，自引：0，他引：1  

Marco Marani  Enrica Belluco  Sergio Ferrari  Sonia Silvestri  Andrea D'Alpaos  Stefano Lanzoni  Alessandra Feola  Andrea Rinaldo   《Estuarine, Coastal and Shelf Science》2006,69(3-4):414

The present paper describes observations, analyses and models of salt-marsh channel network and vegetation patterns with the aim of contributing to the development of predictive models of ecological and morphological co-evolution. Existing and new observations are described, with particular emphasis on remote sensing and ancillary field surveys, which are shown to allow reliable, accurate and repeatable quantitative characterizations of landform and vegetation properties over the spatial scales of interest. The observed channel network morphological characters are then used as the basis and validation of models describing the emergence of channel network and vegetation spatial patterns. In particular, with reference to observations performed in the Venice Lagoon, the note describes: (i) new, 2-cm resolution, characterizations of channel network geometry obtained from “proximal sensing” photographic observations; (ii) the reliable quantitative maps of salt-marsh vegetation which may be retrieved from hyperspectral remote sensing data and field ancillary observations; (iii) a synthesis of recent and new analyses of the statistical properties of vegetation and landform spatial organization, that may be inferred from the maps so derived; (iv) recent and new conceptual and quantitative ecological and geomorphic models developed and validated by remote-sensing and field observations. A coherent observational and theoretical eco-morphodynamic framework is then proposed.  相似文献   

非常规管节点疲劳寿命分析与计算   总被引：6，自引：1，他引：6  

谭开忍肖熙  黄小平 《海洋工程》2005,23(3):51-54,59

对非常规管节点的疲劳寿命进行了分析研究，用SESAM计算疲劳载荷，应用精细有限元分析计算热点应力，用规范的S—N曲线计算管节点的疲劳寿命。通过实例计算表明，这些处理对非常规管节点疲劳寿命分析与计算是很有效的。  相似文献   

The recovery of the Barents Sea capelin (Mallotus villosus) from a larval point of view     

Fossum  P. 《ICES Journal of Marine Science》1992,49(2):237-243

  相似文献   

潜艇疲劳载荷的概率模型   总被引：1，自引：0，他引：1  

黄小平  崔维成 《海洋工程》2003,21(3):18-23

探讨了建立潜艇疲劳载荷概率模型的方法，引入了正态分布和两参数威布尔分布两种概率模型。两参数威布尔分布较适合于用来描述潜艇下潜深度分布的概率特征。可根据潜艇的设计参数、任务及航行区域等因素来选取最可能的分布形式获得潜深分布密度函数。潜艇疲劳热点部位的应力(应变)幅值分布，可由应力(应变)和潜深的关系通过相应的变换得到。  相似文献   

Influences of Nutrient Outwelling from the Mangrove Swamp on the Distribution of Phytoplankton in the Matang Mangrove Estuary, Malaysia   总被引：1，自引：0，他引：1  

Katsuhisa Tanaka  Poh-Sze Choo 《Journal of Oceanography》2000,56(1):69-78

Distributions of dissolved nutrients and Chl. a were investigated in the Sangga Besar River Estuary in the well-managed Matang Mangrove Forest in West Malaysia. In the estuary, spring tide concentrations of ammonium, silicate and phosphate were higher than those in the neap tide, which suggests that these nutrients are flushed from the mangrove area by the inundation and tidal mixing of the spring tide. Ammonium comprised over 50% of the dissolved inorganic nitrogen in the spring tide, while nitrite tended to dominate in the neap tide, indicating the predominance of nitrification inside the estuary in neap tides. Nutrient concentrations in the creek water were higher than those of estuarine water, indicating the nutrient outwelling from the mangrove swamp and ammonium regeneration from mangrove litter in the creek sediments. The maximum concentration of Chl. a in spring tides reached 80 g/l while it was below 20 g/l in the neap tides. These variations in the phytoplankton biomass and nutrients probably reflect the greater nutrient availability in the spring tide due to outwelling from the mangrove swamp and creek.  相似文献   

东海海域海水中颗粒氨基酸(PAA)的组成与含量的分布调查研究     

李烈英  张星君  纪明侯 《海洋科学集刊》2004,46(46):100-105

海水中的有机物的含量微少，约为0.5~2.0 C mg/L，但其种类复杂。其中以溶解有机物(DOM)为主，而颗粒有机物(POM)所占比例则更少。大洋海水中的POM主要来源于浮游生物等的死骸及其分解碎屑；另外还有海水中受风浪影响所进行的DOM-POM的动力平衡产物。近岸海水还受河流和大气带入的陆源尘影响。POM主要由颗粒氨基酸(PAA)组成。即由Asp、Glu、Thr、Ser、Ala、Gly、Leu、Ile、Val、Met、Cys、Tyr、Lys、His、Arg、Phe、Pro等17种氨基酸组成。它们是食碎动物的主要食物，构成海洋食物链的一环，与该水域生产力有直接联系。纪明侯等(1992)于1983年和1984年首次对青岛胶州湾海水中的颗粒氨基酸的组成和含量的变化及其季节变化进行了调查研究。并且在1982年和1984年前后对渤海湾、黄河口和长江口附近水域同样调查研究了表层海水中PAA的组成与含量分布。他们还于1981年7、8月和1982年7、8月乘“科学一号”考察船进一步研究了长江口外东中国海，包括福建省外海、济州岛附近海域和黑潮流域26°00′-33°00′N、123°00′-129°00′E范围内海域的20余个站位的表层海水和部分站位上不同水深中的PAA的组成和含量。兹将调查研究结果报道如下。  相似文献   

Bathymetric shift in the distribution of Atlantic surfclams: response to warmer ocean temperature     

Weinberg  James R. 《ICES Journal of Marine Science》2005,62(7):1444-1453

  相似文献   

Metridia pacifica in Dabob Bay, Washington: The diatom effect and the discrepancy between high abundance and low egg production rates   总被引：1，自引：0，他引：1  

Claudia Halsband-Lenk   《Progress in Oceanography》2005,67(3-4):422

Information on life cycle strategies and reproductive parameters of Metridia pacifica is scarce, despite its importance in the zooplankton of the subarctic Pacific. In many regions it occurs in high abundance, but reproductive rates, when reported, are usually low. This discrepancy was studied in Dabob Bay, Washington, USA, in the context of an investigation of the effect of diatom blooms on the reproductive success of copepod grazers.In situ egg production rates of M. pacifica were measured in spring and mid-summer with standard methods (multi-wells) and a new incubation chamber (spawning towers) that separates the spawning female from its eggs and allows the eggs to develop undisturbed. Many females did not produce eggs, possibly due to a high fraction of immature individuals. Egg production rates were variable, but clutch sizes were higher in spawning towers, and estimates of female egg cannibalism revealed that females consume many eggs shortly after their release. Thus, a separation of females and eggs is mandatory for accurate measurements of M. pacifica egg production rates. The maximum clutch sizes recorded in our study were comparable to measurements for other calanoids. However, unviable eggs were a large fraction of those spawned, independent of incubation method, especially in late winter and early spring. In order to assess whether the diatom effect may be responsible for low viability of embryos and nauplii, we also measured in situ grazing. Adult females were omnivorous, but they ingested some diatoms that rank among the strongest anti-mitotic toxin producers known so far. Although M. pacifica’s vertical migration behavior suggests opportunistic feeding on abundant food during their short stay in the phytoplankton-rich surface, they often ignored the food items that contributed most to microplankton carbon concentrations. Thus, their feeding strategy remains ambiguous. Due to severe reproductive failure early in the season, recruitment was impaired in spring, while the population increased, reaching high abundance in mid-summer when reproductive output was low. While advection and interannual variability in bloom conditions might compensate for the losses described here, the paradox of high Metridia abundance versus low reproductive success still requires further investigation, and methodological constraints need to be ruled out in future studies.  相似文献   

耿贝尔逻辑模型在极值风速和有效波高联合概率分布中的应用   总被引：7，自引：1，他引：7  

周道成  段忠东 《海洋工程》2003,21(2):45-51

首先介绍了耿贝尔逻辑模型，采用该模型对南海海域的涠州岛海洋站的风速和有效波高实测数据进行了分析，结果表明耿贝尔逻辑模型较好地描述了年极值风速和有效波高两随机变量的联合分布；采用得到的极值风浪联合概率分布推算了不同重现期的极值风速和波高，表明考虑风速和波高相关性对设计荷载的确定有显著影响。由于耿贝尔逻辑模型具有函数结构简单，参数估计方便，因此有望成为极值风速和波高联合分布的较理想概率模型。  相似文献