LARGE-SCALE CIRCULATION CONDITIONS AFFECTINGTHE TYPHOON FORMATION OVER THENORTHWEST PACIFIC   总被引：1，自引：0，他引：1  

丁一汇  ELMAR R. RBITBr 《海洋学报(英文版)》1984,3(3):327-338

A contrasting study of the large-scale circulation features responsible for months with many typhoons and months with tew typhoons has revealed that the frequency of typhoon formation over the Northwest Pacific is related to the following conditions:Over the Northwest Pacific, a well-defined ITCZ (Intertropical Convergence Zone) extending eastward to 160°E was displaced to 20°N. At 200 mb, an extensive anomalous anticyclonic circulation prevails over the western and central Pacific. The condition characteristic of a break in the monsoon prevailed in India. The monsoon trough at 500 mb and at the surface over the Indian Peninsula was relatively weak and was accompanied by higher-than-normal rainfall in the northern part of India and lower-than-normal rainfall over the peninsula. In addition, the polar vortex tends to be weak and move to the side of the Northern Hemisphere, opposite to the North Pacific. Finally, abnormally warm water was observed over the Central and Eastern Pacific and abnormally cold  相似文献   

Theoretical wind wave frequency spectra in shallow water     

Wen Shengchang 《海洋学报(英文版)》1988,7(3):325-343

The method developed by Wen et al. (1988 a) for deriving theoretical wind wave frequency spectrum in deep water is extended to the case of water of finite depth, in which a parameter η=H/d is introduced, where H and d represent the average wave height and water depth respectively. The derived spectra reduce to those in deep water when η=0. The case of η=1/2 corresponds to waves impending to break because of the effect of the bottom. Simplified forms of spectra are given. The theoretical results agree with the observed spectra well.  相似文献   

AN ECOSYSTEM MODEL ANALYSIS OF THE EFFECT OF MINE TAILINGS ON THE EUPHOTIC ZONE OF A PELAGIC ECOSYSTEM   总被引：1，自引：0，他引：1  

T. R. PARSONS  T. A. KESSLER  LI GUANGUO 《海洋学报(英文版)》1986,5(3):425-436

A computer analysis was performed on experimental results obtained when mine tailings were added to seawater. The Mixed Upper-Layer Ecotrophie Simulation (MULES) model was tested by changing the extinction coefficient and the abundance of heterotrophic zooflagellates. Increasing the extinction coefficient resulted in a delay of phytoplankton growth, an increase in zooplankton standing stock and better growth of autotrophic flagellates compared with diatoms. Zooflagellates in the ecosystem influence the growth of zooplankton; secondary production by zooplankton was markedly depressed at low levels of zooflagellates. These results are believed to be of general significance for the diagnosis of suspended sediment effects on planktonic ecosystems.  相似文献   

Numerical Simulation of Residual Circulation due to Bottom Rouglmess Variability Under Tidal Flows in A Semi-Enclosed Bay     

槐文信  T.  Komatsu  曾小辉 《中国海洋工程》2005,19(4):601-612

Nowadays there are some chronic serious environmental problems, such as eutrophication, blue tide and so on, in a complicated coastal zone or a semi-enclosed bay, because the water exchanges between an inner bay and an outer sea is weak compared with the supply of contaminant. Under this situation, a method to improve the water quality by 3-dimensional small unsymmetrical structures has been proposed by Komatsu et al. In this paper, several numerical simulations of the tidal current and concentration for various arrangements of bottom roughness in a semi-enclosed model bay are carfled out with a depth-averaged 2-D numerical model. The model is solved by the hybrid finite analytic method with nonstaggered grid. And the SIMPLES algorithm with Rhie and Chow＇ s momentum interpolation technique is used for the simulation. The effect of Komatsu＇ s method for water purification is examined by numerical simulation. The result of numerical experiment indicates that it is possible to generate a new tidal residual current and to activate a tidal exchange by bottom roughness arrangement only.  相似文献   

Impact of sediment organic matter quality on the fate and effects of fluoranthene in the infaunal brittle star Amphiura filiformis     

Selck H  Granberg ME  Forbes VE 《Marine environmental research》2005,59(1):19-45

Hydrophobic contaminants, such as polycyclic aromatic hydrocarbons (PAHs) readily adsorb to organic matter. The aim of this study was to determine the importance of the quality of sedimentary organic matter for the uptake, biotransformation and toxicity of the PAH, fluoranthene (Flu), in the infaunal brittle star Amphiura filiformis. Brittle stars were exposed to a base sediment covered by a 2 cm Flu-spiked top layer (30 microg Flu/g dry wt. sed.), enriched to the same total organic carbon content with either refractory or labile organic matter. The labile carbon source was concentrated green flagellate: Tetraselmis spp. The refractory carbon source was lignin from a paper mill. Tissue concentrations of Flu both in disk and arm-fractions were determined as total Flu, parent Flu (i.e. untransformed), aqueous Flu-metabolites, polar Flu-metabolites and tissue residue Flu (i.e. unextractable). Our results showed that sediment particle ingestion is a pathway by which Flu can enter benthic food webs. Flu toxicity (measured as arm-regeneration), but not net accumulation, was dependent on the nutritional quality of the ingested sediment particles. Flu bioaccumulation could not be attributed solely to equilibrium partitioning between organism lipid content and organic content of the sediment. Biotransformation of Flu by brittle stars was very limited and unaffected by organic matter quality. A. filiformis contributed to the downward transport of Flu from the surface sediment to the burrow lining. The limited breakdown of parent Flu by brittle stars and/or microorganisms was relatively higher in burrows compared to surface sediment, and highest in the presence of labile organic matter. Tissue concentrations were higher in disk than in arms, but the proportion of metabolic products relative to parent Flu was higher in arms than in the disk fraction. We estimate that the yearly mobilization of sediment-associated Flu by arm-regeneration in A. filiformis is in the range of 3.8-29.4 microg total Flu eq. m(-2) year(-1) at a sediment concentration of 30 microg Flu/g dry wt. sed.  相似文献   

Measurement of stress effects (scope for growth) and contaminant levels in mussels (Mytilus edulis) collected from the Irish Sea     

Widdows J  Donkin P  Staff FJ  Matthiessen P  Law RJ  Allen YT  Thain JE  Allchin CR  Jones BR 《Marine environmental research》2002,53(4):327-356

The objective of this research was to quantify the impact of pollution along the coastlines of the Irish Sea. Pollution assessment was based on the combined measurement of scope for growth (SFG), and chemical contaminants in the tissues of mussels (Mytilus edulis) collected from 38 coastal sites around the Irish Sea during June-July in 1996 and 1997. On the UK mainland coast, the SFG showed a general trend with a significant decline in water quality in the Liverpool and Morecambe Bay region. High water quality was recorded along the west coast of Wales, as well as southwest England and northwest Scotland (clean reference sites outside the Irish Sea). Along the coast of Ireland there was a similar trend with reduced SFG within the Irish Sea region. SFG was generally low north of Duncannon and then improved north of Belfast. The poor water quality on both sides of the Irish Sea is consistent with the prevailing hydrodynamics and the spatial distribution of contaminants associated with urban/ industrial development. The decline in SFG of mussels on both sides of the Irish Sea was associated with a general increase in contaminant levels in the mussels. Certain contaminants, including PAHs, TBT, sigmaDDT, Dieldrin, gamma-HCH, PCBs, and a few of the metals (Cd, Se, Ag, Pb), showed elevated concentrations. Many of these contaminants were particularly elevated in the coastal margins of Liverpool Bay, Morecambe Bay and Dublin Bay. A quantitative toxicological interpretation (QTI) of the combined tissue residue chemistry and SFG measurements indicated that at the majority of coastal sites, c. 50 to > 80% of the observed decline in SFG was due to PAHs as a result of fossil fuel combustion and oil spills. TBT levels were highest at major ports and harbours, but these concentrations only made a minor contribution to the overall reduction in SFG. At no sites were individual metals accumulated to concentrations that could cause a significant effect on SFG. The study identified many sites where the observed reduction in SFG was far greater than predicted from the limited number of chemical contaminants analysed, thus indicating the presence of additional 'unknown toxicants'. Sewage (containing domestic, agricultural and industrial components) appears to be an important contributor to reduced SFG and linear alkylbenzenes (LABs) and As may provide suitable 'sewage markers'. There was a highly significant positive correlation between SFG and As (P < 0.001). This relationship may be due to reduced As uptake by algal food material and mussels at sites with elevated P04 concentrations (e.g. at sites with sewage inputs). Phosphate is a known competitive inhibitor of As accumulation, at least in algae. The results highlight that further research is required on 'sewage markers' in mussels. The SFG approach therefore provides a rapid, cost-effective and quantitative measure of pollution impact, as well as a means of identifying the causes through a QTI of tissue contaminants levels. It also serves to identify the presence of unidentified toxicants and areas that require further study.  相似文献   

1985年空间海洋学的状况和展望     

D.J.贝克  倪振荣 《海洋开发与管理》1986,(3)

1984年海洋学工程的主要措施是在空间建立海洋观察站。新的海军遥控海洋测向系统卫星(NROSS)和欧洲空间站的地球资源卫星(ERS—Ⅰ)已得到政府的批准,列入了预算项目,开展了利用卫星调查内容的计划和操作运行的计划。NROSS 的传感器有用于风的 NASA(国家航空和航天局)的传播计量器;用于水面温度,冰的性质和海冰边端的微波无线  相似文献   

大西洋中脊的热液矿泉     

R．P.VonHerzen 《海洋地质前沿》1997,(2)

在过去10年中，通过国际合作，对大西洋中肯的热液矿泉及周围地质背景进行了研究。TAG热液矿泉位于26°N，45°W，距大西洋中脊轴数公里，它是世界卜已发现的最大热液矿泉之一．这个活动的热泉位于一直径为10m的烟囱上，该烟囱位于一直径为150－200m、高40m的椭圆形硫化矿山上．在这个硫化矿山附近几公里范围内还发现了几个不活动的热泉。TAG靠近两条转换断层之间的大西洋中脊．区域重力调查表明，TAG北部的剪切带在向北漂移．分析TAG海底玄武岩表明，源岩在10－15km深处．从旁侧声纳资料看出，TAG由两个复杂的烟囱组成．近海底地球…  相似文献   

LARGE-SCALE CIRCULATION CONDITIONS AFFECTING THE HURRICANE FORMATION OVER THE NORTH ATLANTIC OCEAN     

丁一汇  ELMAR R. REITER 《海洋学报(英文版)》1985,4(1):21-34

A contrasting study of the large-scale circulation features responsible for months or seasons with many hurricanes and those with few hurricanes has revealed that the frequency of hurricane formation over the North Atlantic Ocean is enhanced by the following conditions:There exists a well-developed subtropical high-pressure belt displaced to the north; a deep Icelandic low; a stronger-than-normal polar vortex with a deep polar trough dipping far southward along the eastern part of the United States; a dominant high-pressure ridge over western Canada and the United States; and a jet stream displaced northward over these regions. At 200 hPa, an anomalous anticyclonic circulation prevails over the subtropical North Atlantic. A stronger-than-normal upper easterly flow prevails. Positive sea surface temperature anomalies prevailing on a seasonal or long-term basis tend to be favorable for the formation of hurricanes.  相似文献   

CHARACTERISTICS ON INTERANNUAL VARIATIONS OF NORTH PACIFIC SST AND ITS RELATION TO EAST ASIA CLIMATE     

解思梅  TAKASHI AOKI  MASATOSHI M. YOSHINO 《海洋学报(英文版)》1987,6(1):68-79

The interannual variations of the monthly sea surface temperature (SST) in the North Pacific (including Equatorial East Pacific) during 1951-1980 are analysed by means of EOF method. The findings are:(1) In the cold and warm ocean current areas, such as the North Pacific Current, the California Current and the Equatorial East Pacific areas, the convergence speeds are the fastest, while in the Kuroshio and the western part of the North Equatorial Current areas they are fast only in winter.(2) The physical features of the first 3 eigenvectors are obvious. The first eigenvector shows that the SST values are high in the south and low in the north in the latitudinal distribution of the SST field. The warm current area, i.e. the northwestern part of the North Pacific is positive and the cold current area, i.e. the southeastern part of the North Pacific including the Eastern Equatorial Pacific is negative. The zero line of the 2nd eigenvector field runs from northeast to southwest, in the same direction as the  相似文献