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1.
The South China Sea,a <Emphasis Type="Italic">cul-de-sac</Emphasis> of North Pacific Intermediate Water 总被引：1，自引：0，他引：1
This study discusses branching of the Kuroshio Current including North Pacific Intermediate Water (NPIW) into the South China Sea (SCS). The spreading path of the subtropical salinity minimum of NPIW is southwestward pointing to the Luzon Strait between Taiwan and Luzon islands. Using a large collection of updated hydrography, results show that the SCS is a cul-de-sac for the subtropical NPIW because even the NPIW’s upper boundary neutral density surface σ N = 26.5 is completely blocked by the Palawan sill and partly blocked by the southern Mindoro Strait. In autumn, NPIW is driven out of the Luzon Strait by the preceding anticyclonic summer monsoon due to an intraseasonal variation and seasonal phase lag response to the weaker summer monsoon. Stronger inflow under winter monsoon than outflow under summer monsoon results in a net annual transport of NPIW of about 1.1 ± 0.2 Sv (1 Sv = 106 m3s−1) into the SCS. This net transport accounts for the anomaly in NPIW transport across the World Ocean Circulation Experiment section P8 (130° E). An earlier study estimated a large westward NPIW transport of about 3.9 ± 0.2 Sv, resulting in a difference of 1.2 ± 0.2 Sv from the basin-wide mean of 2.7 ± 0.2 Sv. Observations are generally in agreement with numerical results although the intraseasonal signal seems to cause a slight bias and remains to be simulated by future model experiments. 相似文献
2.
The unique survey in December 1998 mapped the entire western boundary area of the South China Sea(SCS),which reveals the three-dimensional structure and huge volume transport of the swift and narrow winter western boundary current of the SCS(SCSwwbc) in full scale. The current is found to flow all the way from the shelf edge off Hong Kong to the Sunda Shelf with a width around 100 km and a vertical scale of about 400 m. It appears to be the strongest off the Indo-China Peninsula, where its volume transport reached over 20×10~6 m~3/s. The current is weaker upstream in the northern SCS to the west of Hong Kong. A Kuroshio loop or detached eddy intruded through the Luzon Strait is observed farther east where the SCSwwbc no more exists. The results suggest that during the survey the SCSwwbc was fed primarily by the interior recirculation of the SCS rather than by the"branching" of the Kuroshio from the Luzon Strait as indicated by surface drifters, which is likely a near-surface phenomenon and only contributes a minor part to the total transport of the SCSwwbc. Several topics related to the SCSwwbc are also discussed. 相似文献
3.
Lingling Xie Jiwei Tian Shuwen Zhang Yanwei Zhang Qingxuan Yang 《Journal of Oceanography》2011,67(1):37-46
The complicated flow pattern in the intermediate layer of the Luzon Strait could directly affect the efficiency of the water
and energy exchange between the South China Sea (SCS) and the North Pacific. Here we present a subsurface anticyclonic eddy
in the Luzon Strait deduced using observations conducted in October 2005. On the basis of the hydrographic and current measurements,
an anticyclonic eddy was found in the intermediate layer, i.e., about 26.8–27.3σθ, 500–900 m. It captures part of the SCS Intermediate Water outflow in the northern Luzon Strait, and carries it to flow southward
and then westward back into the SCS in the southern Luzon Strait, with volume transport of about 1.9 × 106 m3 s−1. The simulated results from Hybrid Coordinate Ocean Model also suggest the existence of this anticyclonic eddy that develops
and lingers for a month long. 相似文献
4.
Upper-layer circulation in the South China Sea has been investigated using a three-dimensional primitive equation eddy-resolving
model. The model domain covers the region from 99° to 122°E and from 3° to 23°N. The model is forced by the monthly averaged
European Centre for Medium-Range Weather Forecasts (ECMWF) model winds and the climatological monthly sea surface temperature
data from National Oceanographic Data Center (NODC). Inflow and outflow through the Taiwan Strait and the Sunda shelf are
prescribed monthly from the Wyrtki estimates. Inflow of the Kuroshio branch current in the Luzon Strait is assumed to have
a constant volume transport of 12 Sv (1 Sv = 106 m3/s), and the outflow from the open boundary to the east of Taiwan is adjusted to ensure the net volume transport through all
open boundaries is zero at any instant. The model reveals that a cyclonic circulation exists all year round in the northern
South China Sea. During the winter time this cyclonic eddy is located off the northwest of Luzon, coinciding with the region
of positive wind stress curl in this season. This cyclonic eddy moves northward in spring due to the weakening of the northeast
winds. The cyclonic circulation becomes weak and stays in the continental slope region in the northern South China Sea in
the summer period. The southwest wind can raise the water level along the west coast of Luzon, but there is no anticyclonic
circulation in the northern South China Sea. After the onset of the northeast monsoon winds in fall, the cyclonic eddy moves
back to the region off the west coast of Luzon. In the southern South China Sea and off the Vietnam coast, the model predicts
a similar flow structure as in the previous related studies.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
Application of LICOM to the numerical study of the water exchangebetween the South China Sea and its adjacent oceans 总被引：8，自引：1，他引：8
1 IntroductionThe South China Sea (SCS) is the largestmarginal sea in the western Pacific (see Fig. 1). It con-nects with the SCS through the Taiwan Strait, with thePacific through the Luzon Strait, with the Sulu Seathrough the Mindoro and Balabac Straits and with theJava Sea and Andaman Sea through the Sunda Shelf(For convenience, here we refer to the section at 1.5°N,Fig. 2). It is shown that the seasonal SCS circulation ismostly affected by the summer/winter monsoon, andthe no… 相似文献
6.
吕宋海峡纬向海流及质量输送 总被引：30，自引：6，他引：24
分析和计算了吕宋海峡PR21断面最近海洋调查的部分CTD资料和ADCP资料,再一次证明吕宋海峡常年存在纬向流。但对于天气尺度而言,该流型是多变的。根据高分辨率的海洋环流数值模式4a(1992～1996年)海平面高度(SSH)的输出值,运用地转关系估计了吕宋海峡纬向流的月平均值。研究表明;通过海峡流入、流出南海纬向流的深度一般达到500m左右,200m以上流速较大,平均流速为50cm/s,最大时达80cm/s以上。500m以下的纬向地转流流速较小,通常小于10cm/s.由大洋进入海峡的入流位置位于海峡的中部和南部,月平均入流最大值出现在11月,为50cm/s.位于海峡的北部和南部上层海洋的月平均出流,最大流速亦出现在11月,也为50cm/s,这与秋季北赤道流分叉位置最北(15°N),春季分叉位置最南(14°N)有关。上层流入、流出海峡的流量的月平均值分别约为10×106m3/s和5×106m3/s.当东北季风盛行时(从10月到翌年2月),流入海峡的流量远大于流出海峡的流量,两者的差可达8×106m3/s,而在其他季节两者的差仅为3×106m3/s.这说明东北季风盛行时,会有较多的水从南海南？ 相似文献
7.
Evidence for water exchange between the South China Sea and the Pacific Ocean through the Luzon Strait 总被引：15，自引：1，他引：15
Qu Tangdong 《海洋学报(英文版)》2002,21(2):175-185
An analysis of historical oxygen data provides evidence on the water exchange between theSouth China Sea (SCS) and the Pacific Ocean (PO). In the vicinity of the Luzon Strait (LS) , the dissolved oxygen concentration of sea water is found to be lower on the Pacific side than on the SCS side at depths between 700 and 1500 m (intermediate layer) , while the situation is reversed above 700 m (upper layer) and below 1 500 m (deep layer). The evidence suggests that water exits the SCS in the intermediate layer but enters it from the Pacific in both the upper and the deep layers, supporting the earlier speculation that the Luzon Strait transport has a sandwiched structure in the vertical. Within the SCS basin, the oxygen distribution indicates widespread vertical movement, including the upwelling in the intermediate layer and the downwelling in the deep layer. 相似文献
8.
Carbonate chemistry and projected future changes in pH and CaCO3 saturation state of the South China Sea 总被引：3，自引：0，他引：3
Chen-Tung Arthur Chen Shu-Lun Wang Wen-Chen Chou David D. Sheu 《Marine Chemistry》2006,101(3-4):277-305
To study the dissolved carbonate system in the South China Sea (SCS) and to understand the water mass exchange between the SCS and the West Philippine Sea (WPS), pH, total alkalinity and total CO2 were measured aboard the R/V Ocean Researcher 1. Because of the sill that separates these two seas in the Luzon Strait with a maximum depth of 2200 m, the SCS Deep Water has characteristics similar to those of water at about 2200 m in the WPS. The minimum pH and the maxima of normalized alkalinity and total CO2 commonly found in the open oceans at mid-depth also prevail in the WPS but are, however, very weak in the SCS. Rivers and inflows from Kuroshio Surface and Deep Waters through the Luzon Strait as well as those through the Mindoro Strait transport carbon to the SCS year-round. Meanwhile, the outflowing Taiwan Strait water as well as the SCS Surface and Intermediate Waters of the Luzon Strait transports carbon out of the SCS year-round. The Sunda Shelf is also a channel for carbon transport into the SCS in the wet season and out of the SCS in the dry season.fCO2 data and mass balance calculations indicate that the SCS is a weak CO2 source in the wet season but an even weaker CO2 sink in the dry season. With these facts taken together, the SCS is likely a very weak CO2 source. Anthropogenic CO2 penetrates to about 1500 m in depth in the SCS, and the entire SCS contains 0.60 ± 0.15 × 1015 g of excess carbon. Typical profiles of pH as well as the degree of saturation of each of calcite and aragonite in 1850 and 1997 are presented, and those for 2050 AD are projected. The maximum decrease in pH is estimated to be 0.16 pH units in the surface layer when the amount of CO2 is doubled. It is anticipated that aragonite in the upper continental slope will likely start to dissolve, thereby neutralizing excess CO2 by around 2050 AD. This paper is unique in that it presents the results of the first attempt ever to estimate the past, present and future physico-chemical properties of the world's largest marginal sea. 相似文献
9.
This study examines a Kuroshio main path(KMP) cut-off event east of Taiwan Island occurred in fall-winter2013–2014 and its impacts on the South China Sea(SCS) by analyzing satellite altimetry and mooring observations. Satellite altimeter sea level anomaly(SLA) images reveal a complete process that a huge cyclonic eddy(CE) from the Pacific collided with the Kuroshio and the western boundary from 15 October 2013 to 15 January 2014. Mooring observations evidenced that the Kuroshio upper ocean volume transport was cut off more than 82% from 17×106 m~3/s in September to 3×106 m~3/s in November 2013. The KMP cut-off event caused the Kuroshio branching and intruding into the SCS and strengthened the eddy kinetic energy in the northern SCS west of the Luzon Strait. Using the total momentum as a dynamic criterion to determine the role of eddy collision with the Kuroshio reasonably explains the KMP cut-off event. 相似文献
10.
利用在台湾海峡附近的下放式声学多普勒流速剖面仪(Lowered Acoustic Doppler Current Profiler,LADCP)观测资料和温盐观测资料,通过对连续站的两个季节观测进行正压和斜压潮流分析从而去除潮流得到准定常流,并在此基础上计算了南海和东海之间通过台湾海峡输运的水体及热盐通量。结果表明:台湾海峡大部分海域是半日潮海区(正规半日潮及不正规半日潮海区),半日潮主要分量为太阴半日分潮M2;台湾海峡的水体输运及热盐通量呈现明显的季节变化:夏季台湾海峡内表现为一支东北流向的海流,即台湾海峡暖流,存在3.3 Sv(1Sv=106 m3/s)的东北向水体输运,冬季东北季风较强,西南方向的海流加强,混合层可达到底部,存在1.8 Sv的东北向水体输运。与此对应的热盐通量分别为:夏季热通量为0.34×1015 W,盐通量为118.6×109 g/s;冬季热通量为0.14×1015 W,盐通量为72.9×109 g/s。该结果对台湾海峡通量的研究给出了一个直接观测的准确值,并为相关的数值研究提供了参考。 相似文献
11.
Based on a two-level nested model from the global ocean to the western Pacific and then to the South China Sea（SCS）, the high-resolution SCS deep circulation is numerically investigated. The SCS deep circulation shows a basin-scale cyclonic structure with a strong southward western boundary current in summer（July）, a northeastsouthwest through-flow pattern across the deep basin without a western boundary current in winter（January）,and a transitional pattern in spring and autumn. The sensitivity ... 相似文献
12.
The Luzon Strait transport variations during 1997~2000 总被引：1，自引：0，他引：1
1IntroductionTheSouthChinaSea(SCS)isthelargestmarginalseainSoutheastAsia.TheSCSiscon-nectedtotheopenoceanthroughseveralstraitsbetweenthesurroundinglandmassesandis-lands.TheLuzonStrait(seeFig.1)islocatedinthenortheastoftheSCSbetweenTaiwanIslandandthePhilippineIslands,whichisabout380kmwideanditslargestdepthismorethan2500m.Sincetheotherstraitsareveryshallow,theLuzonStraitistheonlymajorchannelallowingeffectivewaterexchangewiththewesternNorthPacific. Wyrtki(1961)firstlyassocia… 相似文献
13.
卡里马塔海峡水体交换的季节变化 总被引：2，自引：0，他引：2
Four trawl-resistant bottom mounts, with acoustic Doppler current profilers(ADCPs) embedded, were deployed in the Karimata Strait from November 2008 to June 2015 as part of the South China Sea-Indonesian Seas Transport/Exchange and Impact on Seasonal Fish Migration(SITE) Program, to estimate the volume and property transport between the South China Sea and Indonesian seas via the strait. The observed current data reveal that the volume transport through the Karimata Strait exhibits significant seasonal variation. The winteraveraged(from December to February) transport is –1.99 Sv(1 Sv=1×10~6 m~3/s), while in the boreal summer(from June to August), the average transport is 0.69 Sv. Moreover, the average transport from January 2009 to December2014 is –0.74 Sv(the positive/negative value indicates northward/southward transport). May and September are the transition period. In May, the currents in the Karimata Strait turn northward, consistent with the local monsoon. In September, the southeasterly trade wind is still present over the strait, driving surface water northward, whereas the bottom flow reverses direction, possibly because of the pressure gradient across the strait from north to south. 相似文献
14.
根据2001年3月份南海东北部航次调查温、盐资料,分析了2001年冬末春初南海东北部温、盐结构和环流的特征.分析结果表明:观测期间南海东北部环流主要受一次海盆尺度气旋型冷环流支配,冷环流呈现双核结构,垂向尺度接近1000 m.吕宋海峡内侧断面的水交换在600 m以浅海水流入南海,在断面南部(20°N以南)中层和深层有流出,断面法向地转流向西净输运量为6.9×106m3/s;直接的黑潮入侵不超过120.5°E,但有部分的黑潮水沿陆坡达到台湾岛西南部海域,并更有一部分逸入东沙岛以西海域,与南海水混合变性. 相似文献
15.
本文采用美国伍兹霍尔研究所研发的海洋-大气-波浪-泥沙输运耦合模式COAWST(Coupled Dcean-Atmosphere-Wave-Sediment Transport)对南海及邻近海域进行了9 km分辨率的数值模拟研究。结果表明,南海贯穿流的季节变化再现了冬强夏弱的特征,在南海内部冬季呈现气旋环流结构,夏季呈现反气旋环流结构,尤其在冬季其流轴结构更为清晰和稳定,海水从吕宋海峡进入南海,从民都洛海峡、卡里马塔海峡、台湾海峡和巴拉巴克海峡流出,吕宋海峡断面流量与其他4个海峡流量合计在数量级上相当,保持南海海水总量不变。吕宋海峡、卡里马塔海峡、民都洛海峡的流量呈现明显相关性,吕宋海峡流量增大时,民都洛海峡和卡里马塔海峡的流量也相应增大,相关系数分别达到0.78和0.9。通过更适于分析中短期变化的简化绕岛环流理论,定量计算2019年吕宋海峡、黑潮和棉兰老流流量与北赤道流分叉点位置的关系,发现夏季北赤道流分叉点NECBL(North Equatorial Current Bifurcation Latitude)偏南,在13.6°N附近;冬季NECBL偏北,在15.6°N左右,同期黑潮流量减少,棉兰老流流量增加,作为南海贯穿流入流的吕宋海峡流量可达13.4 Sv。吕宋海峡输运补偿了北赤道流到达菲律宾海岸后的北向分支的流量,与棉兰老流的流量呈正相关,相关系数达到0.5361。 相似文献
16.
Sub-seasonal variability of Luzon Strait Transport in a high resolution global model 总被引：1，自引：1，他引：0
The Luzon Strait is the main impact pathway of the Kuroshio on the circulation in South China Sea (SCS). Based on the analysis of the 1997–2007 altimeter data and 2005–2006 output data from a high resolution global HYCOM model, the total Luzon Strait Transport (LST) has remarkable subseasonal oscillations with a typical period of 90 to 120 days, and an average value of 1.9 Sv into SCS. Further spectrum analysis shows that the temporal variability of the LST at different depth is remarkable different. In the upper layer (0–300 m), westward inflow has significant seasonal and subseasonal variability. In the bottom layer (below 1 200 m), eastward outflow exhibits remarkable seasonal variability, while subseasonal variability is also clear. In the intermediate layer, the westward inflow is slightly bigger than the eastward outflow, and both of them have obvious seasonal and subseasonal variability. Because the seasonal variation of westward inflow and eastward outflow is opposite, the total transport of intermediate layer exhibits significant 50–150 days variation, without obvious seasonal signals. The westward Rossby waves with a period of 90 to 120 days in the Western Pacific have very clear correlationship with the Luzon Strait Transport, this indicates that the interaction between these westward Rossby waves and Kuroshio might be the possible mechanism of the subseasonal variation of the LST. 相似文献
17.
Jianyu Hu Hiroshi Kawamura Chunyan Li Huasheng Hong Yuwu Jiang 《Journal of Oceanography》2010,66(5):591-610
Patterns and features of currents and seawater volume transports in the Taiwan Strait have been reviewed by examining the results from more than 150 research papers in recent decades. It is noted that there are diverse or even conflicting viewpoints on these subjects. Here both common and different opinions are summarized. This review paper covers the studies involving in situ measurements and numerical modeling of current velocity, analyses of hydrographic data, and classification of water masses. Generally speaking, there are three currents in the Taiwan Strait: the China Coastal Current along the Fujian coast in the western Taiwan Strait, the extension of the South China Sea Warm Current in the western and central Taiwan Strait, and the Kuroshio’s branch or loop current intruding through the eastern Taiwan Strait. The current pattern in winter is quite different from that in summer, and the currents also exhibit differences between the upper and lower layers. The seawater volume transport through the Taiwan Strait is about 2.3 Sv northward in summer but about 0.8 Sv northward in winter. Both the current pattern and the seawater transport vary with local winds in the Taiwan Strait. This is particularly true in winter when the currents and the transport in the upper layer are significantly affected by strong northeasterly winds. 相似文献
18.
Masachika Masujima Ichiro Yasuda Yutaka Hiroe Tomowo Watanabe 《Journal of Oceanography》2003,59(6):855-869
Oyashio water flowing into the Mixed Water Region (MWR) and the Kuroshio Extension region that forms North Pacific Intermediate
Water (NPIW) has been examined, based on four Conductivity-Temperature-Depth profiler (CTD)/Lowered Acoustic Doppler Current
Profiler (L-ADCP) surveys of water masses and ocean currents. There are two processes by which the Oyashio water intrudes
across the Subarctic Front (SAF): one is a direct cross-nearshore-SAF transport near Hokkaido along the western boundary,
and the other is a cross-offshore-SAF process. Seasonal variations were observed in the former process, and the transport
of the Oyashio water across SAF near Hokkaido in the density range of 26.6–27.4σθ was 5–10 Sv in spring 1998 and 2001, and 0–4 Sv in autumn 2000, mainly corresponding to the change of the southwestward Oyashio
transport. Through the latter process, 5–6 Sv of the Oyashio water was entrained across the offshore SAF from south of Hokkaido
to 150° in both spring 2001 and autumn 2000. The total cross-SAF Oyashio water transport contributing to NPIW formation is
more than 10 Sv, which is larger than previously reported values. Most of the Oyashio water formed through the former process
was transported southeastward through the Kuroshio Extension. It is suggested that the Oyashio intrusion via the latter process
feeds NPIW in the northern part of the MWR, mainly along the Subarctic Boundary and SAF.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
19.
Qingxuan Yang Jiwei Tian Wei Zhao 《Deep Sea Research Part I: Oceanographic Research Papers》2010,57(5):670-676
A field experiment was conducted across the Luzon Strait in July 2007, and a total of 51 profiles covering variables of horizontal velocity, temperature, salinity, and pressure were collected at 11 stations. Using this observation, the volume transport through the Luzon Strait, its differences between July 2007 and October 2005, and the distribution of subtidal flow and geostrophic flow have been investigated. The net transport has a two-layer vertical structure, which is eastward both in the upper layer (<26 kg m?3 σ0), and in the intermediate layer (26–27.3 kg m?3 σ0), while it is westward in the deeper layer (>27.3 kg m?3 σ0), with respective values of 3.0, 4.0, and ?1.5 Sv. The net transport is eastward, and estimated to be 5.5 Sv. The distribution of the subtidal flow in the intermediate layer shows that a westward flow exists in the northern part, countered by an eastward flow existing in the southern part of the strait. This distribution is in direct contrast to the previous results obtained in October 2005, in which a westward flow occurs in the south countered by an eastward flow in the north in the intermediate layer. This suggests that the flow pattern varies greatly from October 2005 to July 2007 not only in the upper layer but also in the intermediate layer. The deep layer, on the other hand, shows few changes between the two observation periods. 相似文献
20.
Primary Study of the Mechanism of Eddy Shedding from the Kuroshio Bend in Luzon Strait 总被引：10，自引：0，他引：10
The mechanism of the anticyclonic eddy's shedding from the Kuroshio bend in Luzon Strait has been studied using a nonlinear
2 1/2 layer model, in a domain including the North Pacific and South China Sea. The model is forced by steady zonal wind in
the North Pacific. Energy analysis is adopted to detect the mechanism of the eddy shedding. Twelve experiments with unique
changes of wind forcing speed (to obtain different Kuroshio transports at Luzon Strait) were performed to examine the relationship
between the Kuroshio transport (KT) and the eddy shedding events. In the reference experiment with KT of 22.7 Sv (forced with
zonal wind idealized from the annual mean wind stress from the COADS data set), the interval of eddy shedding is 70 days and
the shed eddy centers at (20°N, 117.5°E). When the Kuroshio bend extends westward, the southern cyclonic perturbation grows
so rapidly as to form a cyclonic eddy (18.5°N, 120.5°E) because of the frontal instability in the south of the Kuroshio bend.
In the evolution of the cyclonic eddy, it cleaves the Kuroshio bend and triggers the separation of the anticyclonic eddy.
In statistical terms, anticyclonic eddy shedding occurs only when KT fluctuates within a moderate range, between 21 Sv and
28 Sv. When the KT is larger than 28 Sv, a stronger frontal instability south of the Kuroshio bend tends to generate a cyclonic
eddy of size similar to the width of the Luzon Strait. The bigger cyclonic eddy prevents the Kuroshio bend from extending
into the SCS and does not lead to eddy shedding. On the other hand, when the KT decreases to less than 21 Sv, the frontal
instability south of the Kuroshio bend is so weak that the size of corresponding cyclonic eddy is smaller than half the width
of the Luzon Strait. The cyclonic eddy, lacking power, fails to cleave the Kuroshio bend and cause separation of an anticyclonic
eddy; as a result, no eddy shedding occurred then, either. 相似文献