Acoustic semi-tomography in studies of the structure and function of the marine ecosystem     

Orlowski  Andrzej 《ICES Journal of Marine Science》2003,60(6):1392-1397

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Numerical Solution of Lock-Release Gravity Current with Viscous Self-Similar Regime     

张立柱李行伟  陈国谦 《中国海洋工程》2004,18(1):157-162

Lock-release gravity currents with a viscous self-similar regime are simulated by use of the renormalization group(RNG) k - ε model for Reynolds-stress closure. Besides the turbulent regime with initially a slumping phase of a conslant current front speed and later an inviseid self-similar phase of front speed decreasing as t^-1/3(where t is the time measured from release), the viseous self-similar regime is satisfactorily reproduced with front speed decreasing as t^-4/5,consistent with well known experimental observations.  相似文献   

Spatial, temporal and diel variations of fish assemblages at two sandy beaches in the Sepetiba Bay, Rio de Janeiro, Brazil     

Andr Luiz Machado Pessanha  Francisco Gerson Araújo 《Estuarine, Coastal and Shelf Science》2003,57(5-6):817-828

Fish assemblages from two beaches, one in the inner and the other in the outer Sepetiba Bay (latitude: 22°54′–23°04′S; longitude: 43°34′–44°10′W), Southeast Brazil, were sampled by beach seine net, simultaneously, on both seasonal and diel scales, between August 1998 and June 1999. Sites were selected to encompass different environmental conditions which reflect the two bay zones, thus providing a comprehensive assessment of the factors influencing surf zone fish assemblages, and their spatial, seasonal and diel variations. A total of 55 fish species was recorded, mostly young-of-the-year. Anchoa tricolor, Micropogonias furnieri, Gerres aprion, Diapterus rhombeus, Harengula clupeola, Atherinella brasiliensis and Mugil liza were numerically dominant and contributed to 95.2% of the total fish catches. Strong differences in fish assemblages were observed between the two areas, with higher number of species in the outer bay. Increases in fish numbers occurred in winter, while the highest biomass occurred in winter and summer. Transparency, followed by salinity, was responsible for most of the spatial variability and played an important role in structuring fish assemblages. Overall, diel patterns did not reveal any significant trends; however, if we consider each season separately, an increase in fish numbers during the day with peak at sunset was observed in winter, and a higher biomass occurred at night in winter and summer. Species preferences for various combinations of environmental variables are responsible for shifts in the structure and overall abundance of assemblages and dictated some patterns. The sciaenid M. furnieri, the second most abundant species, occurred only in the inner zone, being more abundant in winter. The species of Engraulidae were more abundant in the outer zone in winter/spring during the day. The gerreids G. aprion and D. rhombeus occurred mainly in summer. Overall, temporal fluctuations act more at a specific level than at a structural one, and may be linked to some particular stages of the fish life cycle, but do not significantly influence the spatial organization.  相似文献   

安徽宣城地区中晚更新世风成堆积与环境变迁   总被引：25，自引：7，他引：25  

杨达源  房迎三 《海洋地质与第四纪地质》1991,11(2):97-104

通过对宣城向阳中晚更新世沉积剖面的综合研究,认为该剖面与中国北方同时代的黄土—古土壤剖面相比较,虽然长江下游以南地区中晚更新世多个冰期中风成堆积的单层厚度与累积厚度,亦即风成物质的沉积通量与沉积速率均比北方黄土区要小,但它们所反映的气候与环境的变化具有明显的可比性。  相似文献   

天津海岸带经济开发的地质环境和环境工程地质问题   总被引：3，自引：0，他引：3       下载免费PDF全文

杨锦贤 《海洋开发与管理》1994,11(3):36-40

本文揭示了天津海岸带影响经济开发的四个方面的地质环境特点；着重探讨三个方面的环境工程地质问题；并防止其形成和减轻地灾害的对策进行了研究。  相似文献   

胶州湾海域水质预测   总被引：3，自引：0，他引：3  

孙英兰  孙长青  王丽霞  徐鸿楷 《中国海洋大学学报(自然科学版)》1994,(Z1)

在已建潮流模型的基础上,用ADI法建立了胶州湾扩大域变动边界的平流—扩散输运模型,以COD为指示因子,预测了胶州湾海域1995年、2000年的水质、青岛环海公路海上段、沧口区北半部污水截流、北水南调、集中排放以及胶州湾西部经济开发对海域水质的影响等。为青岛市环保部门制定环保规划提供决策依据。  相似文献   

海洋声层析的基本原理和应用     

朱芸  吕连港 《海洋科学进展》2002,20(4):70-75

从射线声学和简正波声学的角度，概述了海洋声层析的基本理论，包括射线走时反演、简正波走时反演、简正波相位反演和简正波水平折射层析。海洋声层析以反演海水温度和流速为基础。还总结了声层析在海洋学研究中的应用。  相似文献   

A quantitative evaluation of the impact of beam trawling on benthic fauna in the southern North Sea     

Piet  G. J.; Rijnsdorp  A. D.; Bergman  M. J. N.; van Santbrink  J. W.; Craeymeersch  J.; Buijs  J. 《ICES Journal of Marine Science》2000,57(5):1332-1339

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海洋生态环境监测的指标体系研究   总被引：1，自引：0，他引：1  

单宇  李正炎 《海洋湖沼通报》2007,200(2):52-56

本文在总结国内外各种海洋生态监测方法的基础上,构建生物分布指数、生物暴露指数和生物反应指数,并由此确定生态质量总指教。生态质量总指数可以综合反映特定海洋环境的生物群落特征,典型污染物在生物体内的蓄积特征以及生物体对环境污染的生理生化反应特征,因此可以应用于近岸海洋环境质量的生态监测。  相似文献   

南极普里兹湾气旋的生消发展   总被引：3，自引：4，他引：3  

解思梅  郝春江  梅山  刘克威  魏立新 《海洋学报》2002,24(6):11-19

利用1989～2000年现场观测的气象资料,特别是自1997年以来在南极考察船上接收的NOAA卫星极轨高分辨的卫星云图,研究了普里兹湾气旋的生消发展;提出了夏季绕极气旋进入普里兹湾内也会发展加强,在湾内东风带里也能生成气旋的新观点,修正了普里兹湾仅是气旋墓地的不全面说法,从而进一步完善了南极西风带绕极气旋和东风带上气旋生消发展的理论;研究了普里兹湾冰-气-海相互作用的机理,解释了气旋发生、发展的物理过程.用整体动力学输送法计算了进入普里兹湾980205号绕极气旋爆发性发展的能量交换,指出气旋在超过冰坝进入冰间湖可以获得巨大的热量,使气旋迅速发展成为具有南极特色的强风暴,风力达12级以上,平均风速为38m/s;瞬时最大风速达100m/s.  相似文献