南海南部粉红色 Globigerinoides ruber 冰期旋回及影响因素     

徐建  翦知湣 《海洋地质与第四纪地质》2003,23(4):59-64

对南海南部ODP1143站氧同位素11-5e期大约2ka分辨率的粉红色Globigerinoides ruber进行分析,发现其冰期／间冰期旋回与代表全球冰量的底栖有孔虫氧同位素(δ^18O)的变化相反,即在间冰期时含量低,而冰期时高,与其他海区的记录相反。海水表层温度和温跃层深度转换函数结果以及碎壳率的变化显示,在一定的温度背景下,温跃层深度的变化可能是控制粉红色G．ruber冰期旋回的主要因素,而这段时期南海南部溶解作用的影响则不明显。  相似文献   

Reliability-Based Optimal Design for Very Large Floating Structure     

张淑华 《中国海洋工程》2003,17(1)

1 .ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅａｐｐｒａｉｓａｌｏｆａｇｏｏｄｄｅｓｉｇｎｆｏｒａｖｅｒｙｌａｒｇｅｆｌｏａｔｉｎｇｓｔｒｕｃｔｕｒｅ(ＶＬＦＳ)ｔｈａｔｗｉｌｌｓｅｒｖｅｉｎａｓｐｅｃｉ ｆｉｅｄｏｃｅａｎａｒｅａｒｅｑｕｉｒｅｓｔｈａｔｔｈｅｓｔｒｕｃｔｕｒａｌｓｙｓｔｅｍｂｅｅｃｏｎｏｍｉｃａｌｌｙｄｅｓｉｇｎｅｄ ,ｔｈｅｒｅｑｕｉｒｅｍｅｎｔｓｆｏｒｉｔｓｆｕｎｃｔｉｏｎｂｅｓａｔｉｓｆｉｅｄａｎｄｔｈｅｓｔｒｕｃｔｕｒｅｋｅｅｐｓｓｔａｂｌｅｉｎｉｔｓｗｈｏｌｅｓｅｒｖｉｃｅｐｅｒｉｏ…  相似文献   

周期浅析     

战淑芸  杨淑瑞 《海洋预报》1992,9(4):47-51

本文分析了滑动平均的数据处理方法对周期分析结果产生的影响。提出了过程变量同号积分的数据处理方法,并对亚洲西风指数序列进行了试验分析。分析结果表明,周期的长短与振幅的大小有密切关系,亚洲逐日西风指数的周期振荡具有明显的季节特征。  相似文献   

Simulations of Annual Cycle of Phytoplankton Production and the Utilization of Nitrogen in the Yellow Sea     

Tian?TianEmail author  Hao?Wei  Jian?Su  Changsoo?Chung 《Journal of Oceanography》2005,61(2):343-357

A nutrient dynamic model coupled with a 3D physical model has been developed to study the annual cycle of phytoplankton production in the Yellow Sea. The biological model involves interactions between inorganic nitrogen (nitrate and ammonium), phosphate and phytoplankton biomass. The model successfully reproduces the main features of phytoplankton-nutrient variation and dynamics of production. 1. The well-mixed coastal water is characterized by high primary production, as well as high new production. 2. In summer, the convergence of tidal front is an important hydrodynamic process, which contributes to high biomass at frontal areas. 3. The evolution of phytoplankton blooms and thermocline in the central region demonstrate that mixing is a dominant factor to the production in the Yellow Sea. In this simulation, nitrate- and ammonium-based productions are estimated regionally and temporally. The northern Yellow Sea is one of the highly ranked regions in the Yellow Sea for the capability of fixing carbon and nitrogen. The annual averaged f-ratio of 0.37 indicates that regenerated production prevails over the Yellow Sea. The result also shows that phosphate is the major nutrient, limiting phytoplankton growth throughout the year and it can be an indicator to predict the bloom magnitude. Finally, the relative roles of external nutrient sources have been evaluated, and benthic fluxes might play a significant role in compensating 54.6% of new nitrogen for new production consumption.  相似文献   

Seasonally Hypersaline Estuaries in Mediterranean-climate Regions     

J.L. Largier  J.T. Hollibaugh  S.V. Smith 《Estuarine, Coastal and Shelf Science》1997,45(6):789-797

Data collected in three Californian estuaries indicate that hypersaline conditions exist during the dry summers typical of a Mediterranean climate. The generalised seasonal and longitudinal hydrographic structures are described and explained. It is argued that this seasonal hypersalinity is common and that it represents a major class of estuaries. The observed accumulation of salt indicates surprisingly long residence times in small basins which have free exchange with the ocean. This semi-isolation of the inner basin leads to a large build-up or severe depletion of nutrients, pollutants and plankton in these systems. Of concern are the trends to increase pollutant loading in the same systems that are experiencing an increase in residence times owing to freshwater extraction in the watershed.  相似文献   

Excess CO2 and pHexcess in the Intermediate Water Layer of the Northwestern Pacific     

Andrey Andreev  Makio Honda  Yuichiro Kumamoto  Masashi Kusakabe  Akihiko Murata 《Journal of Oceanography》2001,57(2):177-188

Excess CO₂ and pH_excess showing an increase in dissolved inorganic carbon and a decrease in pH from the beginning of the industrial epoch (middle of the 19th century) until the present time have been calculated in the intermediate water layer of the northwestern Pacific and the Okhotsk Sea. It is concluded that: (1) The Kuril Basin (Okhotsk Sea) and the Bussol' Strait areas are characterized by the greatest concentrations of excess CO₂ at isopycnal surfaces due to the processes of formation and transformation of intermediate water mass. (2) The largest difference in excess CO₂ concentration between the Okhotsk Sea and the western subarctic Pacific (about 8 µmol/kg) is found at the = 27.0. (3) The difference in excess CO₂ between the western subarctic Pacific and subtropical regions is significant only in the upper part of the intermediate water layer ( = 26.7–27.0). (4) About 10% of the excess CO₂ accumulation in the subtropical north Pacific is determined by water exchange with the subarctic Pacific and the Okhotsk Sea.  相似文献   

Cod migration patterns in relation to temperature: analysis of storage tag data   总被引：1，自引：0，他引：1  

Stensholt  Boonchai K. 《ICES Journal of Marine Science》2001,58(4):770-793

  相似文献   

动荷载作用下海底粉土的孔压响应及其动强度   总被引：5，自引：0，他引：5  

冯秀丽  叶银灿  马艳霞  林霖 《中国海洋大学学报(自然科学版)》2002,32(3):429-433

本文选用近海分布较广的粉土为研究对象 ,利用室内动三轴试验结果 ,找出动荷载作用下粉土的动应力应变关系 ,分析模拟波浪荷载作用下粉土中的孔压响应、临界循环次数 ,确定波浪作用下粉土的应力状态、破坏临界循环次数 ,判断不同深度处的粉土发生液化的可能性及发生液化所需要的时间 ;研究粉土在动荷载作用下的强度降低 ,为海上工程设计和施工提供科学依据。  相似文献   

黄、渤海无机氮的收支模式初探   总被引：8，自引：1，他引：8  

王保栋  单宝田  战闰  藏家业 《海洋科学》2002,26(2):33-36

根据黄、渤海无机氮的收支状况，首次提出了黄、渤海无机氮的稳态收支模式。模式研究结果表明，大气沉降、陆源输入和海底输入的无机氮通量分别占黄、渤海无机氮浮游植物总需求量的3%、4%和12%。无机氮的外部输入约占总需求量的1/5，其他部分则由水柱中的内部再循环（再生）供给。  相似文献   

Atmospheric forcing of the eastern tropical Pacific: A review   总被引：1，自引：8，他引：1  

Jorge A. Amador  Eric J. Alfaro  Omar G. Lizano  Victor O. Magaa 《Progress in Oceanography》2006,69(2-4):101

The increase in marine, land surface, atmospheric and satellite data during recent decades has led to an improved understanding of the air–sea interaction processes in the eastern tropical Pacific. This is also thanks to extensive diagnoses from conceptual and coupled ocean–atmosphere numerical models. In this paper, mean fields of atmospheric variables, such as incoming solar radiation, sea level pressure, winds, wind stress curl, precipitation, evaporation, and surface energy fluxes, are derived from global atmospheric data sets in order to examine the dominant features of the low level atmospheric circulations of the region. The seasonal march of the atmospheric circulations is presented to depict the role of radiative forcing on atmospheric perturbations, especially those dominating the atmosphere at low levels.In the tropics, the trade winds constitute an important north–south energy and moisture exchange mechanism (as part of the low level branch of the Hadley circulation), that determines to a large extent the precipitation distribution in the region, i.e., that associated with the Inter-Tropical Convergence Zone (ITCZ). Monsoonal circulations also play an important role in determining the warm season precipitation distribution over the eastern tropical Pacific through a large variety of air–sea–land interaction mechanisms. Westward traveling waves, tropical cyclones, low latitude cold air intrusions, and other synoptic and mesoscale perturbations associated with the ITCZ are also important elements that modulate the annual rainfall cycle. The low-level jets of the Gulf of California, the Intra-Americas Sea (Gulf of Mexico and Caribbean Sea) and Chocó, Colombia are prominent features of the eastern tropical Pacific low-level circulations related to sub-regional and regional scale precipitation patterns. Observations show that the Intra-Americas Low-Level Jet intensity varies with El Niño/Southern Oscillation (ENSO) phases, however its origin and role in the westward propagation and development of disturbances that may hit the eastern tropical Pacific, such as easterly waves and tropical cyclones, are still unclear. Changes in the intensity of the trade winds in the Caribbean Sea and the Gulf of Mexico (associated with eastern tropical Pacific wind jets) exert an important control on precipitation by means of wind–topography interactions. Gaps in the mountains of southern Mexico and Central America allow strong wind jets to pass over the continent imprinting a unique signal in sea surface temperatures and ocean dynamics of the eastern tropical Pacific.The warm pools of the Americas constitute an important source of moisture for the North American Monsoon System. The northeastern tropical Pacific is a region of intense cyclogenetic activity, just west of the coast of Mesoamerica. Over the oceanic regions, large-scale properties of key variables such as precipitation, moisture, surface energy fluxes and wind stress curl are still uncertain, which inhibits a more comprehensive view of the region and stresses the importance of regional field experiments. Progress has been substantial in the understanding of the ocean and atmospheric dynamics of the eastern tropical Pacific, however, recent observational evidence such as that of a shallow meridional circulation cell in that region, in contrast to the classic concept of the Hadley-type deep meridional circulation, suggests that more in situ observations to validate theories are still necessary.This paper is part of a comprehensive review of the oceanography of the eastern tropical Pacific Ocean.  相似文献