首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
The Beibu Gulf circulation plays an imPOrtant role in the long--term water rnass transportinside the gulf. It is also closely related to the Guangxi untal water mass transport and self-purification. Hence, it is of practical imPOrtance to study the circulation in the gUlf. The cir-culation in the gUlf is very comlicated, and is rnainly gOverned by wind, water density gradi-ent, the current outside the gulf and the bathpoetry. In spring, a cold water rnass generatesln the center of the gulf…  相似文献   

2.
From August 2002 to September 2004 a high-resolution mooring array was maintained across the western Arctic boundary current in the Beaufort Sea north of Alaska. The array consisted of profiling instrumentation, providing a timeseries of vertical sections of the current. Here we present the first-year velocity measurements, with emphasis on the Pacific water component of the current. The mean flow is characterized as a bottom-intensified jet of O (15 cm s−1) directed to the east, trapped to the shelfbreak near 100 m depth. Its width scale is only 10–15 km. Seasonally the flow has distinct configurations. During summer it becomes surface-intensified as it advects buoyant Alaskan Coastal water. In fall and winter the current often reverses (flows westward) under upwelling-favorable winds. Between the storms, as the eastward flow re-establishes, the current develops a deep extension to depths exceeding 700 m. In spring the bottom-trapped flow advects winter-transformed Pacific water emanating from the Chukchi Sea. The year-long mean volume transport of Pacific water is 0.13±0.08 Sv to the east, which is less than 20% of the long-term mean Bering Strait inflow. This implies that most of the Pacific water entering the Arctic goes elsewhere, contrary to expected dynamics and previous modeling results. Possible reasons for this are discussed. The mean Atlantic water transport (to 800 m depth) is 0.047±0.026 Sv, also smaller than anticipated.  相似文献   

3.
The offshore oil and gas industry is facing the prospect of de-commissioning thousands of installations in the coming decades. In some parts of the world the issue is already pressing. The financial cost of complete removal is significant, and therefore the prospect of leaving part of the installation in situ is attractive. The way forward, though, is not clear. Despite the success of rigs-to-reef projects in the US it is unclear whether such initiatives are transferable to other contexts given very different physical and jurisdictional contexts. This paper explores current legal frameworks including international law and the state of play in Australia compared with that in the US and UK. Tentative recommendations are made for future developments in this area.  相似文献   

4.
I~IOWIn winter, on the impacts Of the Chriolis force and the current along the shore of the EastChina ho, the residual current from the Changjiang River flows south along the shore and enters the ~ Bay in the north, then it moves out of the bay in the south and flows southin the East China Sea (Su and Wang, 1989; Zhu and Shen, 1997). In recent years, scholars have made further analyse on obSerVed date, and have obtained more profound viewson the residual current and mass transport (Pn …  相似文献   

5.
Wave–current laboratory experiments have shown that the logarithmic current profile observed in pure current flows is modified due to the presence of waves. When waves propagate opposite the current, an increase in the current intensity is achieved near the mean water level, while a reduction is obtained for following waves and currents. With the aim of analyzing these nonlinear effects along the whole water column, an Eulerian wave–current model is presented. In contrast to previously presented wave–current models, the present is able to include the variation of the free surface elevation due to the wave motion and the effect of a non hydrostatic pressure field. Therefore it does not restrict its application to waves in shallow waters. Moreover, the model is able to simulate all the possible angles between waves and currents.  相似文献   

6.
《海洋学报(英文版)》1997,16(4):537-551
Ｒｅｓｅａｃｈ　ｏｎ　ｔｈｒｅｅ－ｄｉｍｅｎｓｉｏｎａｌ　ｔｉｄｅ　ｃｕｒｒｅｎｔ　ｍａｔｈｅｍｔｉｃａｌ　ｍｏｄｅｌ　ｏｆ　ｃｏａｓｔ　ａｎｄ　ｉｔｓ　ａｐｐｌｉｃａｔｉｏｎTXＲｅｓｅａｃｈｏｎｔｈｒｅｅ－ｄｉｍｅｎｓｉｏｎａｌｔｉｄｅｃｕｒｒｅｎ...  相似文献   

7.
ＩＮＴＲＯＤＵＣＴＩＯＮＩｎｅａｒｌｙ 1 96 0’ｓ,ｔｈｅｔｉｄｅａｎｄｔｉｄａｌｃｕｒｒｅｎｔｉｎｔｈｅＢｅｉｂｕＧｕｌｆｗｅｒｅｏｂｓｅｒｖｅｄａｎｄａｎａｌｙｓｅｄｂｙＣｈｉｎａｉｎｃｏｏｐｅｒａｔｉｏｎｗｉｔｈＶｉｅｔｎａｍ1) .ＴｈｅｓｙｓｔｅｍａｔｉｃｓｔｕｄｉｅｓｏｆｔｉｄｅａｎｄｔｉｄａｌｃｕｒｒｅｎｔｉｎｔｈｅＢｅｉｂｕＧｕｌｆｗｅｒｅｆｉｒｓｔｃａｒｒｉｅｄｏｕｔｂｙＦａｎｇ (1 986 ) .Ｔｈｅｈｉｓｔｏｒｙｏｆｎｕｍｅｒｉｃａｌｓｔｕｄｙｏｆｔｉｄｅａｎｄｔｉｄａｌｃｕｒｒｅｎｔ…  相似文献   

8.
ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｒｅａｒｅｍａｎｙｍｏｄｅｌｓｔｏｃａｌｃｕｌａｔｅｔｈｅｃｕｒｒｅｎｔｓｉｎｔｈｅＥａｓｔＣｈｉｎａＳｅａａｎｄｏｔｈｅｒｎｅｉｇｈｂｏｒ ｉｎｇｓｅａｓ ,ａｎｄｓｏｍｅｏｆｔｈｅｍａｒｅｂｅｉｎｇｍｏｄｉｆｉｅｄａｎｄｄｅｖｅｌｏｐｅｄｗｉｔｈｔｈｅｔｉｍｅ .Ｔｈｅｓｅｍｏｄｅｌｓａｒｅａｓｆｏｌｌｏｗｓ :(1 )ｔｈｅｆｉｎｉｔｅｅｌｅｍｅｎｔｍｅｔｈｏｄ ,ａｎｄａｃｏｍｂｉｎａｔｉｏｎｏｆｆｉｎｉｔｅｅｌｅｍｅｎｔｍｅｔｈｏｄｗｉｔｈｔｈｅａｃｃｕｒａｔｅｓｏｌ…  相似文献   

9.
-Based on a two-dimensional numerical M2 tidal model of the Huanghai and Bohai Seas, sediment transport of particles with different sizes in the computational area is given. It is concluded that tidal currents play an important role in sediment transport and deposition in the Huanghai and Bohai Seas.  相似文献   

10.
Using an irregularly oscillating tray and flume,a series of experiments are completed to evaluate bed-load sediment transport rate under irregular wave-current coexistent fild.Testing conditions include three interaction angles 0°,45°,90° and two kinds of median sizes (0.38 and 1.10 mm).The results of transport rate show that the net sediment transport rate can be expressed approximately as the function of the maximum bottom shear stress of waves,mean shear stress of current and the grain size.  相似文献   

11.
Two onboard observation campaigns were carried out in the western boundary region of the Philippine Sea in December 2006 and January 2008 during the 2006/07 El Niño and the 2007/08 La Niña to observe the North Equatorial Current (NEC), Mindanao Current (MC), and Kuroshio current system. The NEC and MC measured in late 2006 under El Niño conditions were stronger than those measured during early 2008 under La Niña conditions. The opposite was true for the current speed of the Kuroshio, which was stronger in early 2008 than in late 2006. The increase in dynamic height around 8°N, 130°E from December 2006 to January 2008 resulted in a weakening of the NEC and MC. Local wind variability in this region did not appear to contribute to changes in the current system.  相似文献   

12.
-Mainly on the basis of the data obtained during PRC/US bilateral TOGA cruises, abnormal variation occurred during the 1986/1987 El Nino is shown in this paper about the thermal structure and circulation of the upper western tropical Pacific Ocean. The effects of the abmormal variation on the subtropical high over the Northwest Pacific Ocean are discussed. During the El Nino: (1) In the east part of the western tropical Pacific Ocean (the subsurface temperature data on the 165° E section are taken as an example), the water wanner than 29 C in the upper layer spread on the longitudinal section and positive temperature anormalies appeared in a large area of the sea surface. (2) In the west part of the western tropical Pacific Ocean (the subsurface temperature data on the 137°E section are representative ), the cross section occupied by the upper layer warmer water ( T >28 ℃ ) became shrunk, and the sea surface temperature showed negative amomalies. (3) The eastward flows in the upper layer of the 165°  相似文献   

13.
ＡＢＦＧｍｏｄｅｌｆｏｒｃａｌｃｕｌａｔｉｏｎｏｆｔｉｄａｌｃｕｒｒｅｎｔａｎｄｄｉｆｆｕｓｉｏｎｏｆｐｏｌｌｕｔａｎｔｓｉｎｎｅａｒｓｈｏｒｅａｒｅａｓ￥ＳｈｉＦｅｎｇｙａｎ；ａｎｄＺｈｅｎｇ；Ｌｉａｎｙｕａｎ（ＳｔａｔｅＫｅｙＬａｂｏｒａｔｏｒｙ...  相似文献   

14.
《Coastal Engineering》2002,45(1):1-18
  相似文献   

15.
The mesoscale dynamics of the Scottish side of the Faroe–Shetland Channel have been investigated using synoptic in situ and remote sensing observations. A cold core cyclonic eddy, identified from an AVHRR image, had a diameter of about 50 km and surface current speeds of up to 50 cm s-1; it appeared to be attached to the 800 m isobath as it moved north-eastward along the edge of the channel at about 8 cm s-1. Speeds in the slope current were about 50 cm s-1 but increased to 70 cm s-1 where the current was compressed by the eddy. Offshore, over the 1000 m isobath in the cooler water, speeds in the current were slower (ca. 20 cm s-1). North-west of the Shetlands the offshore edge of the slope current was deflected across the channel for a distance of about 70 km from the shelf edge. The speed of drifters in the slope current increased to over 60 cm s-1 as they moved anti-cyclonically around this deflection. CTD profiles suggest that the movement of the surface waters was mirrored in the deep water of the channel. The deflection carried a very large quantity of North Atlantic Water into the central part of the channel; its cause and ultimate fate are not known, although it is likely to have had a significant impact on the dynamics of the channel.  相似文献   

16.
Altimeter and in situ data are used to estimate the mean surface zonal geostrophic current in the section along 115°E in the southern Indian Ocean,and the variation of strong currents in relation to the major fronts is studied.The results show that,in average,the flow in the core of Antarctic Circumpolar Current(ACC) along the section is composed of two parts,one corresponds to the jet of Subantarctic Front(SAF) and the other is the flow in the Polar Front Zone(PFZ),with a westward flow between them.The mean surface zonal geostrophic current corresponding to the SAF is up to 49 cm · s-1 at 46°S,which is the maximal velocity in the section.The eastward flow in the PFZ has a width of about 4.3 degrees in latitudes.The mean surface zonal geostrophic current corresponding to the Southern Antarctic Circumpolar Current Front(SACCF) is located at 59.7 °S with velocity less than 20 cm · s-1.The location of zonal geostrophic jet corresponding to the SAF is quite stable during the study period.In contrast,the eastward jets in the PFZ exhibit various patterns,i.e.,the primary Polar Front(PF1) shows its strong meridional shift and the secondary Polar Front(PF2) does not always coincide with jet.The surface zonal geostrophic current corresponding to SAF has the significant periods of annual,semi-annual and four-month.The geostrophic current of the PFZ also shows significant periods of semi-annual and four-month,but is out of phase with the periods of the SAF,which results in no notable semi-annual and fourmonth periods in the surface zonal geostrophic current in the core of the ACC.In terms of annual cycle,the mean surface zonal geostrophic current in the core of the ACC shows its maximal velocity in June.  相似文献   

17.
The dynamic feature of the Modaomen Estuary (ME) in the Pearl River Delta in southern China has been the subject of extensive research. In previous studies, wave–current interaction (WCI) was often neglected due to its complexity. This study uses a coupled hydrodynamic module TELEMAC-2D and wave propagation module TOMAWAC in the TELEMAC-Mascaret modeling system to quantify the effects of WCI on the hydrodynamics in the ME. The coupled wave and current modeling system was well validated against the field measurements at selected locations. The model results show that WCI varies with the seasonal change in runoff in the ME. The effect of waves on the currents is insignificant during the wet season with a current change of no more than 0.07 m/s; but, in contrast, the currents have a noticeable effect on waves. However, during the dry season, the interactions of waves and currents on each other are found to be equally significant. When wave model and current model are coupled, the velocity could increase up to a maximum of 0.30 m/s and decrease up to a maximum of 0.17 m/s. WCI is greatly affected by the propagation directions of wave and current in both seasons. Generally, wave height decreases and current increases for a following wave and current; wave height increases and current decreases for an opposing wave and current. The effects of waves on currents change with the tide. Changes are larger during neap tide than during spring tide, and stronger during ebb tide than during flood tide.  相似文献   

18.
Ocean current forecasting is still in explorative stage of study. In the study, we face some problems that have not been met before. The solving of these problems has become fundamental premise for realizing the ocean current forecasting. In the present paper are discussed in depth the physical essence for such basic problems as the predictability of ocean current, the predictable currents, the dynamical basis for studying respectively the tidal current and circulation, the necessity of boundary model, the models on regions with different scales and their link. The foundations and plans to solve the problems are demonstrated. Finally a set of operational numerical forecasting system for ocean current is proposed.  相似文献   

19.
INTRoDUCTIONAdiagnosticmodel(WangandYuan,1997)hasbeenusedtocalculatethecurrentintheTaiwanStrait(TS)duringsummer.Astothesemidiagnosticmodel,SarkisyanandYu(1983)firstlysetupasemidiagnosticmodel,whichisalsocalledanadjustablem0del,andtheyusedittocalculatethecirculati0n0vertheAtlanticOcean.YuanandPan(l995)alsodevelopedathree-di-mensi0nalsemidiagnosticmodelandcalculatedthecirculationovertheEastChinaSea.Theprog-mpticm0dlfortheoceans,whichissimilartothesemidiagnosticmodel,wasstudiedearlierby…  相似文献   

20.
On the basis of a three-dimensional weakly nonliear theory of Lagrangian residual current in the Baroclinic shallow seas, a diagnostic numerical calculation of wind-driven, thermohaline and tide-induced Lagrangian residual current in the Bohai Sea is made. The model involves the Richardson number in the eddy viscosity coefficient, wind, thcrmolialine and tidal effects in the focing terms. The runoff of the Huanghe River and a part of the Huanghai Warm Water coming from the Huanghai Sea through the Bohai Sea Strait is also considered. The velocity-splitting method is adopted. The wind-driven circu lation, thermohaline circulation and the tide-induced Lagrangian residual circulation are also obtained individually and analysed. The dynamics of the three main eddies in the Lagrangian mean circulation is discussed. Finally, the numerical result is partly verified with the observed data.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号