泛黄海海区的物理海洋特征     

袁业立  郭炳火  孙湘平 《海洋科学进展》1993,(3)

本文扼要综述了至今的我国海洋调查的重要事件,它们包括:1)全国性综合性调查,2)特定海洋现象的专项调查,3)各项中外合作海洋调查.在海洋调查基础上,本文还综述了泛黄海区主要海洋环流分量的特征,并尽可能从数学物理角度简要阐明了这些海洋现象的形成和维持机制.  相似文献   

南大西洋风场和海浪场时空特征分析   总被引：3，自引：0，他引：3  

刘金芳  黄海仁  张晓慧  唐晓卫  任帅 《海洋湖沼通报》2002,18(3):1-8

本文根据1950～1995年共46a的南大西洋船舶气象报资料,按1*1和5*5网格统计的风、浪要素进行分析研究。通过分析每月风、浪各要素的等值线分布图,得出南大西洋风场与海浪场季节变化特点不如北半球各大洋显著,但仍有较明显的季节变化,只是季节性差异较小,冬季风比夏季风强盛,相应的平均波高、大浪大涌频率也较大;盛行风向、风浪传播方向、涌浪传播方向基本一致,低纬地区常年盛行东南浪,高纬地区则盛行偏西向浪。本文为船舶远洋交通运输、远洋出访和科学试验等活动,提供了较为翔实的风场和浪场资料及变化规律。  相似文献   

Tidal Mixing in the Kuril Straits and Its Impact on Ventilation in the North Pacific Ocean     

Tomohiro Nakamura  Takahiro Toyoda  Yoichi Ishikawa  Toshiyuki Awaji 《Journal of Oceanography》2004,60(2):411-423

A numerical study using a 3-D nonhydrostatic model has been applied to baroclinic processes generated by the K ₁ tidal flow in and around the Kuril Straits. The result shows that large-amplitude unsteady lee waves are generated and cause intense diapycnal mixing all along the Kuril Island Chain to levels of a maximum diapycnal diffusivity exceeding 10³ cm²s⁻¹. Significant water transformation by the vigorous mixing in shallow regions produces the distinct density and potential vorticity (PV) fronts along the Island Chain. The pinched-off eddies that arise and move away from the fronts have the ability to transport a large amount of mixed water (∼14 Sv) to the offshore regions, roughly half being directed to the North Pacific. These features are consistent with recent satellite imagery and in-situ observations, suggesting that diapycnal mixing within the vicinity of the Kuril Islands has a greater impact than was previously supposed on the Okhotsk Sea and the North Pacific. To examine this influence of tidal processes at the Kurils on circulations in the neighboring two basins, another numerical experiment was conducted using an ocean general circulation model with inclusion of tidal mixing along the islands, which gives a better representation of the Okhotsk Sea Mode Water than in the case without the tidal mixing. This is mainly attributed to the added effect of a significant upward salt flux into the surface layer due to tidal mixing in the Kuril Straits, which is subsequently transported to the interior region of the Okhotsk Sea. With a saline flux into the surface layer, cooling in winter in the northern part of the Okhotsk Sea can produce heavier water and thus enhance subduction, which is capable of reproducing a realistic Okhotsk Sea Mode Water. The associated low PV flux from the Kuril Straits to the open North Pacific excites the 2nd baroclinic-mode Kelvin and Rossby waves in addition to the 1st mode. Interestingly, the meridional overturning in the North Pacific is strengthened as a result of the dynamical adjustment caused by these waves, leading to a more realistic reproduction of the North Pacific Intermediate Water (NPIW) than in the case without tidal mixing. Accordingly, the joint effect of tidally-induced transport and transformation dominating in the Kuril Straits and subsequent eddy-transport is considered to play an important role in the ventilation of both the Okhotsk Sea and the North Pacific Ocean. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Tsunami Travel Time Atlas for the Atlantic Ocean     

N. Nirupama  I. Nistor  K. Ponnambalam  T. S. Murty 《Marine Geodesy》2006,29(3):179-199

Compared to the Pacific Ocean, tsunamis are rare both in the Atlantic and Indian Oceans. However, the December 26, 2004, tsunami demonstrated that, no matter how rare they may be, when a major tsunami occurs, it could be very disastrous. The most basic information in tsunami warning center requires are charts showing tsunami travel times to various locations around the rim of the ocean. With this in mind, a tsunami travel time atlas for the Atlantic Ocean is in preparation. The Caribbean Sea is also included in this Atlas, as it is more or less a part of the Atlantic Basin.  相似文献   

Decadal-to-interdecadal response and adjustment of the North Pacific to prescribed surface forcing in an oceanic general circulation model   总被引：2，自引：0，他引：2  

FANG Jiabei  RONG Xinyao  YANG Xiuqun 《海洋学报(英文版)》2006,25(3):11-24

1IntroductionAvariety of observational evidences have shownthe existence of decadal-to-interdecadal variabilitiesin the Pacific Ocean.The phase transition for thosevariabilities could be gradual or abrupt.A strikingexample for abrupt change is the so-call…  相似文献   

An East-West Comparison of the Transition Zone Coastal Pelagic Nekton of the North Pacific Ocean     

Richard D. Brodeur  Joseph P. Fisher  Yasuhiro Ueno  Kazuya Nagasawa  William G. Pearcy 《Journal of Oceanography》2003,59(4):415-434

During the 1980s and 1990s, scientific research cruises were conducted in both the eastern and western boundary regions of the North Pacific Ocean. The main purpose of these cruises was to examine the abundance and distribution patterns of juvenile salmon in coastal waters. These studies created one of the most extensive databases ever collected on the species composition of coastal Transition Zone epipelagic nekton in the North Pacific Ocean. Catch data from two purse seine and two surface trawl surveys (one each from off northern Japan and eastern Russia and off the West Coast of the U.S.) were examined using multivariate techniques to analyze the community structure of nektonic cephalopods, elasmobranchs, and teleosts in the coastal zone during the summer and autumn months. Juvenile salmonids are generally among the most common species caught, but in terms of overall abundance, other potential competitors with juvenile salmon, such as small squids and clupeoid fishes predominated the catches. Species diversity and dominance varied among areas and gear types. Distinct assemblages were found in each area, but the two regions had closely related species occupying similar ecological positions in each habitat. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

Characteristic analysis of wind field and sea wave field over the NW Pacific Ocean   总被引：2，自引：0，他引：2  

刘金芳  唐晓卫  何丹华 《海洋预报》2001,18(Z1)

The NW Pacific Ocean is not onIy the only transportation way between America andAsia, but also the source influencing on inIand climate and marine variability of adjacentseas in China. Based on ship observation data during l950 - l995 in the NW Pacific,with data from several hundreds to 30 thousand in every 5"x5" grid network, throughanalyzing the monthly mean directions of prevailing wind, wave and swelI, wind speed,pressure, wave height and frequencies of gaIe of 6 and 8 sca1e, high sea…  相似文献   

Cyclic fluctuations of anoxia during Cretaceous time in the South Atlantic Ocean   总被引：1，自引：0，他引：1  

T. Jacquin  P.Ch. de Graciansky 《Marine and Petroleum Geology》1988,5(4)

The holes of the DSDP-IPOD program in the South Atlantic Ocean document two major anoxic events during Oxfordian to middle Albian times and secondly from late Cenomanian to Santonian times. The black shales formed during these two anoxic events differ in their rhythmicity and origin.During Lower Cretaceous time, the anoxic conditions resulted from the confined, euxinic nature of the basins. The rhythmicity of these black shales probably does not result from a global phenomenon (climatic or tectono-eustatic), but from local conditions resulting from the slender dimensions of the young ocean basin(s). The diversity and the diachroneity of the deposits from the south to the north precisely reflect the dynamics of the oceanic spreading.During Upper Cretaceous time, the anoxic conditions fluctuated in relation to a mid-water oxygen-minimum zone. The rhythmicity of black shale deposition seems to result from a global phenomenon, because of the widespread occurrence of the event. In the South Atlantic ocean, the cyclic fluctuations of anoxia were due to cyclic variations in the depth of the mid-water oxygen-minimum zone. There is no simple process to explain such rhythmicity. It probably results from the interplay of the three main variables which characterize the oceans at the time of the Cenomanian-Turonian boundary: the increased rate of sea floor spreading, high sea-levels and low water-circulation.  相似文献   

ENSO related variations in biogeochemistry of AA and HA in settling particles along the equatorial Pacific Ocean     

Lallan P. Gupta  Hodaka Kawahata 《Journal of Oceanography》2007,63(4):695-709

Four year-long time-series sediment trap experiments were conducted along the equatorial Pacific Ocean in order to understand the biogeochemistry of particulate organic matter (POM) on the basis of amino acid (AA) and hexosamine (HA) compositions of the settling particles. Total mass flux in the study area varied over 4 orders of magnitude without a common seasonality among all trap sites. Planktonic blooms were apparent in terms of total mass and AA fluxes at the easternmost end of the Niño-4 region. AA fluxes closely followed the total mass flux profiles, suggesting that increased particle flux delivered a greater amount of labile OM to the deep ocean. A labile OM index (LI)-based classification showed that during the El Niño conditions in 2002, the eastern side of the equatorial Pacific transported relatively more labile OM than the western equatorial Pacific. An overall change in AA and HA composition of settling particles could be revealed with the help of discriminant analysis, suggesting that settling particles during El Niño were compositionally different from those settling during La Niña condition in the equatorial Pacific.  相似文献   

Spatial and temporal variability in coccolithophore abundance and production of PIC and POC in the NE subarctic Pacific during El Niño (1998), La Niña (1999) and 2000     

M.S. Lipsen  D.W. Crawford  P.J. Harrison 《Progress in Oceanography》2007,75(2):304-325

Seasonal variations in coccolithophore abundance, chlorophyll, nutrients and production of particulate organic and inorganic carbon (POC and PIC) were determined along a coastal to oceanic east-west transect (Line P) culminating at Ocean Station Papa in the northeastern subarctic Pacific between 1998 and 2000. Offshore stations generally exhibited low seasonality in chlorophyll concentrations, with moderate seasonality in POC production. Near shelf stations showed a similar pattern to offshore stations, but were also characterized by sporadic events of higher POC productivity. During the 1998 El Niño, June was characterized by low chlorophyll and POC productivity along the transect, presumably as a result of depleted surface nitrate. In contrast, during the 1999 La Niña, and in 2000, higher POC productivity and surface nitrate occurred along the transect in June. Chlorophyll and POC productivity were similar in late summer in all 3 years. The coccolithophore population was usually numerically dominated by Emiliania huxleyi, particularly in June. Along the transect, abundance of coccolithophores was much higher in June during the 1998 El Niño (mean of 221 cells ml⁻¹) than in the 1999 La Niña (mean of 40 cells ml⁻¹), with their abundance in late summers of both years being very low. Abundances were even higher along the transect in June and the late summer of 2000 with sporadic ‘blooms’ of >1000 cells ml⁻¹ at some stations (cruise averages 395 and 552 cell ml⁻¹, respectively). Production rates of PIC did not consistently correlate with areas of high coccolithophore abundance. PIC production was high (100-250 mg C m⁻² d⁻¹) along the transect during June 1998, and low (1-40 mg C m⁻² d⁻¹) during both winters, June 1999 and during late summers of 1998 and 1999. The year 2000 was more complicated, with high rates of PIC production accompanying high abundance of coccolithophores in late summer, but lower rates of PIC production accompanying high coccolithophore numbers in June. Our data suggest that the abundance of coccolithophores and the production rates of PIC in the subarctic are higher than previously thought. Occasional PIC:POC production ratios of 1 or greater in 1998 and 2000 suggest that coccolithophores in this region could have a significant impact on the efficiency of the biological carbon pump.  相似文献