共查询到18条相似文献，搜索用时 140 毫秒
1.
In order to quantitatively estimate the volume and property transports between the South China Sea and Indonesian Seas via the Karimata Strait, two trawl-resistant bottom mounts, with ADCPs embedded, were deployed in the strait to measure the velocity profile as part of the South China Sea-Indonesian Seas transport/exchange (SITE) program. A pair of surface and bottom acoustic modems was employed to transfer the measured velocity without recovering the mooring. The advantage and problems of the instruments in this field work are reported and discussed. The field observations confirm the existence of the South China Sea branch of Indonesian throughflow via the Karimata Strait with a stronger southward flow in boreal winter and weaker southward bottom flow in boreal summer, beneath the upper layer northward (reversal) flow. The estimate of the averaged volume, heat and freshwater transports from December 2007 to March 2008 (winter) is (-2.7 ± 1.1) × 10 6 m3/s, (-0.30 ± 0.11) PW, (-0.18 ± 0.07) × 106m3/s and from May to September 2008 (summer) is (1.2 ± 0.6) × 106m3/s, (0.14 ± 0.03) PW, (0.12 ± 0.04) × 106m3/s and for the entire record from December 2007 to October 2008 is (-0.5 ± 1.9) × 10 6 m3/s, (-0.05 ± 0.22) PW, (-0.01 ± 0.15) × 106m3/s (negative/positive represents southward/northward transport), respectively. The existence of southward bottom flow in boreal summer implies that the downward sea surface slope from north to south as found by Fang et al. (2010) for winter is a year-round phenomenon. 相似文献
2.
The previous studies show that the spreading path of the subtropical salinity minimum of the North Pacific Intermediate Water (NPIW) is southwestward pointing to the Luzon Strait. Based on the P -vector method and generalized digital environmental model (GDEM) data, the volume transport of NPIW through Luzon Strait and the upward transport on the NPIW lower and upper boundaries are calculated to examine the destiny of NPIW in the South China Sea (SCS). On the annual mean, the estimation of NPIW transport into the SCS through the Luzon Strait is 1.72 Sv (1Sv=10 6 m 3 /s). The upward transport over the SCS is 0.31 Sv on the NPIW upper boundary and 1.31 Sv on the NPIW lower boundary. There is no strait or passage deeper than the surface for the NPIW to extend, except for the Luzon Strait. For the volume balance in the SCS NPIW, the volume transport of 2.72 Sv has to flow out of the SCS NPIW layer through the Luzon Strait. 相似文献
3.
The structure of current speed and the variability of volume transports of the Kuroshio in the Tokara-kaikyo and Osumi-kaikyo are discussed on the basis of data of KER in the period from 1977 to 1984. The average geostrophic transport through these two straits is estimated to be 24. 5×106 m3/s and only 1/12 of the transport is through the Osumi-kaiky5. Countercurrents on both sides of the Kuroshio trunk are observed in the Tokara-kaikyo. Calculation indicates that the average geostrophic current speed is less than the GEK current speed, systematically. On the basis of the current measurements, the northward transports through the Taiwan Strait in winter and summer are estimated to be 1. 05×106and 3. 16×106m3/s, respectively. From Chu's data (1976) the average transport of the Kuroshio flowing into the East China Sea passing through the passage east of Taiwan is about 29. 3×106m3/s. From Miita and Ogawa's data (1984) the average transport through the Tsushima-kaikyo is 3. 6×106m3/s. Thus the volume 相似文献
4.
The annual mean volume and heat transport sketches through the inter-basin passages and transoceanic sections have been constructed based on 1 400-year spin up results of the MOM4p1. The spin up starts from a state of rest, driven by the monthly climatological mean force from the NOAA World Ocean Atlas(1994). The volume transport sketch reveals the northward transport throughout the Pacific and southward transport at all latitudes in the Atlantic. The annual mean strength of the Pacific-Arctic-Atlantic through flow is 0.63×106 m3/s in the Bering Strait. The majority of the northward volume transport in the southern Pacific turns into the Indonesian through flow(ITF) and joins the Indian Ocean equatorial current, which subsequently flows out southward from the Mozambique Channel, with its majority superimposed on the Antarctic Circumpolar Current(ACC). This anti-cyclonic circulation around Australia has a strength of 11×106 m3/s according to the model-produced result. The atmospheric fresh water transport, known as P-E+R(precipitation minus evaporation plus runoff), constructs a complement to the horizontal volume transport of the ocean. The annual mean heat transport sketch exhibits a northward heat transport in the Atlantic and poleward heat transport in the global ocean. The surface heat flux acts as a complement to the horizontal heat transport of the ocean. The climatological volume transports describe the most important features through the inter-basin passages and in the associated basins, including: the positive P-E+R in the Arctic substantially strengthening the East Greenland Current in summer; semiannual variability of the volume transport in the Drake Passage and the southern Atlantic-Indian Ocean passage; and annual transport variability of the ITF intensifying in the boreal summer. The climatological heat transports show heat storage in July and heat deficit in January in the Arctic; heat storage in January and heat deficit in July in the Antarctic circumpolar current regime(ACCR); and intensified heat transport of the ITF in July. The volume transport of the ITF is synchronous with the volume transport through the southern Indo-Pacific sections, but the year-long southward heat transport of the ITF is out of phase with the heat transport through the equatorial Pacific, which is northward before May and southward after May. This clarifies the majority of the ITF originating from the southern Pacific Ocean. 相似文献
5.
A review on the South China Sea western boundary current 总被引：7，自引：2，他引：5
The advances in understanding the South China Sea (SCS) western boundary current (SCSwbc) have been reviewed since the works of Dale (1956) and Wyrtki (1961) in the middle of the 20th century. The features of the pattern of SCSwbc and the oceanic phenomena associated with it are focused on. The current is driven mainly by monsoon over the SCS and partially by winds over the tropical Pacific governed by the island rule. The SCSwbc exhibits strong seasonal variation in its direction and patterns. In winter, the current is strong and flows southwestward along the South China shelf and slope from the east of Dongsha Islands to the northern central Vietnamese coast, then turns to the south along the central and southern Vietnamese coast, and finally partially exits the SCS through the Karimata Strait. In summer and early fall, the SCSwbc can be divided into three segments based on their characteristics. The southern segment is stable, flowing northward from the Karimata Strait up to about 11 N, where it separates from the coast forming an eastward offshore current. The separation of the current from Vietnamese coast induces some striking features, such as upwelling and cold sea-surface temperature. The middle segment off the central Vietnamese coast may have a bimodal behavior: northward coastal current and meandering current in early summer (June-July), and cyclonic gyre in later summer and early fall (August-September). The northern segment is featured by the summer SCS Warm Current on the South China shelf and a southwestward subsurface current along the continental slope. 相似文献
6.
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
7.
A numerical study of the South China Sea deep circulation and its relation to the Luzon Strait transport 总被引：7，自引：1，他引：7
Yuan Dongliang 《海洋学报(英文版)》2002,21(2):187-202
A fine-resolution MOM code is used to study the South China Sea basin-scale circulationand its relation to the mass transport through the Luzon Strait. The model domain includes the South China Sea, part of the East China Sea, and part of the Philippine Sea so that the currents in the vicinity of the Luzon Strait are free to evolve. In addition, all channels between the South China Sea and the Indonesian seas are closed so that the focus is on the Luzon Strait transport. The model is driven by specified Philippine Sea currents and by surface heat and salt flux conditions. For simplicity, no wind-stress is applied at the surface.The simulated Luzon Strait transport and the South China Sea circulation feature a sandwich vertical structure from the surface to the bottom. The Philippine Sea water is simulated to enter the South China Sea at the surface and in the deep ocean and is carried to the southern basin by western boundary currents. At the intermediate depth, the net Luzon Strait transport is out of t 相似文献
8.
During the summer of 2012, the fifth CHINARE Arctic Expedition was carried out, and a submersible mooring system was deployed in M5 station located at(69°30.155'N,169°00.654'W) and recovered 50 d later. A set of temperature, salinity and current profile records was acquired. The characteristics of these observations are analyzed in this paper. Some main results are achieved as below.(1) Temperature generally decreases while salinity generally increases with increasing depth. The average values of all records are 2.98°C and 32.21 psu.(2)Salinity and temperature are well negatively correlated, and the correlation coefficient between them is –0.84.However, they did not always vary synchronously. Their co-variation featured different characters during different significant periods.(3) The average velocity for the whole water column is 141 mm/s with directional angle of347.1°. The statistical distribution curve of velocity record number gets narrower with increasing depth. More than85% of the recorded velocities are northward, and the mean magnitudes of dominated northward velocities are100–150 mm/s.(4) Rotary spectrum analysis shows that motions with low frequency take a majority of energy in all layers. The most significant energy peaks for all layers are around 0.012 cph(about 3.5 d period), while the tidal motion in mooring area is nonsignificant.(5) Velocities in all layers feature similar and synchronous temporal variations, except for the slight decrease in magnitude and leftward twist from top to bottom. The directions of velocity correspond well to those of surface wind. The average northward volume transport per square meter is0.1–0.2 m3/s under southerly wind, but about –0.2 m3/s during northerly wind burst. 相似文献
9.
From the eastern Indonesian cruise from November 14 to 23, 2007, CTD (conductivity, temperature, depth profiler) /ADCP (acoustic Doppler current profiler)casting and seawater sampling were done at 25 stations around Waigeo Island near New Guinea Island. It was found overall westward intrusion of the south Pacific waters into the Seram Sea and southward spreading of the north and south Pacific waters into the Seram Sea. There is westward residual flow along the channel between Waigeo and New Guinea within upper 200 m with the maximum speed up to 50 cm/s, and much weaker eastward flow in the lower layer (< 10 cm/s) due to blocking by the shallow sill at the west of the Dampier Strait. The abrupt change of bottom topography induces active horizontal and vertical mixing which results in a three-layered current system with a major through-flow of -0.99 Sv (Sv = 10 6 m 3 /s) into the Seram Sea; the transports in the upper and the lower layers are -1.14 Sv and -0.24 Sv (westward), respectively, and in the middle there is a return flow with the transport of +0.39 Sv (eastward). 相似文献
10.
东海细菌丰度和生产力的季节变化及与浮游植物生物量和生产力的关系 总被引：4，自引：0，他引：4
The East China Sea is a productive marginal sea with a wide continental shelf and plays an important role in absorbing atmospheric carbon dioxide and transferring terrigenous organic matter to the open ocean. To investigate the roles of heterotrophic bacteria in the biogeochemical dynamics in the East China Sea, bacterial biomasses(BB) and productions(BP) were measured in four cruises. The spatial distributions of the BB and the BP were highly season-dependent. Affected by the Changjiang River discharge, the BB and the BP were high in shelf waters(bottom depth not deeper than 50 m) and generally decreased offshore in August 2009. In December 2009 to January 2010, and November to December 2010, the BB and the BP were high in waters with medium bottom depth. The onshore-offshore decreasing trends of the BB and the BP also existed in May–June 2011, when the BB was significantly higher than in other cruises in shelf break waters(bottom depth deeper than 50 m but not deeper than 200 m). The results of generalized additive models(GAM) suggest that the BB increased with the temperature at a range of 8-20°C, increased with the chlorophyll concentration at a range of 0.02–3.00 mg/m3 and then declining, and decreased with the salinity from 28 to 35. The relationship between the temperature and the log-transformed bacterial specific growth rate(SGR) was linear. The estimated temperature coefficient(Q10) of the SGR was similar with that of the phytoplankton growth. The SGR also increased with the chlorophyll concentration. The ratio of the bacterial to phytoplankton production ranged from less than 0.01 to 0.40, being significantly higher in November–December 2010 than in May–June 2011. Calculated from the bacterial production and growth efficiency, the bacterial respiration consumed, on average, 59%, 72% and 23% of the primary production in August 2009, November–December 2010, and May–June 2011, respectively. 相似文献
11.
Yasushi Fukamachi Kay I. Ohshima Naoto Ebuchi Tadao Bando Kazuya Ono Minoru Sano 《Journal of Oceanography》2010,66(5):685-696
Time-series data of the vertical structure of the Soya Warm Current (SWC) were obtained by a bottom-mounted acoustic Doppler
current profiler (ADCP) in the middle of the Soya Strait from September 2006 to July 2008. The site of the ADCP measurement
was within the coverage of the ocean-radar measurement around the strait. The volume transport of the SWC through the strait
is estimated on the basis of both the vertical structure observed by the ADCP and the horizontal structure observed by the
radars for the first time. The annual transport estimates are 0.62–0.67 Sv (1 Sv = 106 m3s−1). They are somewhat smaller than the difference between the previous estimates of the inflow and outflow through other straits
in the Sea of Japan, and smaller than those obtained in the region downstream of the strait during 2004–05 (0.94–1.04 Sv).
The difference in the two periods may be attributed to interannual variability of the SWC and/or the different measurement
locations. 相似文献
12.
《Deep Sea Research Part II: Topical Studies in Oceanography》1999,46(6-7):1137-1168
A water-mass analysis is carried out in Fram Strait, between 77.15 and 81.15°N, based on three-dimensional large-scale potential temperature and salinity distributions reconstructed from the MIZEX 84 hydrographic data collected in summer 1984. Combining these distributions with the geostrophic flow field derived from the same data in a companion paper (Schlichtholz and Houssais, 1999), the heat, fresh water and volume transports are estimated for each of the water masses identified in the strait. Twelve water masses are selected based on their different origins. Among them, the Polar Water (PW) enters Fram Strait from the Arctic Ocean both over the Greenland Slope and over the western slope of the Yermak Plateau. In the Atlantic Water (AW) range, four modes with distinct geographical distributions are indentified. In the Deep Water range, the Eurasian Basin Deep Water (EBDW) is confined to the Lena Trough and to the Molloy Deep area where it is involved in a cyclonic circulation. The warm and shallower mode of the Norwegian Sea Deep Water (NSDW), concentrated to the west, is mainly seen as an outflow from the Arctic Ocean while the cold and deeper mode, essentially observed to the east, enters the strait from the Greenland Sea. Apart from the EBDW, there is a tendency for all water masses of polar origin to flow along the Greenland Slope. The two most abundant water masses, the AW and the NSDW, occupy as much as 67% of the total water volume. The southward net transport of PW through Fram Strait is about 1 Sv at 78.9°N. At the same latitude, the net transport of AW is southward and equal to about 1.7 Sv. Only the transport of the warm mode (AWw) is northward, amounting to 0.2 Sv. The overall net outflow of the Deep Waters to the Greenland Sea is about 2.6 Sv. Two upper water masses, the fresh (AWf) and the cold (AWc) mode of the AW, and one deep-water mass, the NSDW, appear to be produced in the strait, with production rates, between 77.6 and 79.9°N, of about 0.2, 1.0 and 1.7 Sv, respectively. A southward net fresh-water transport through the strait of about 2000 km3 yr−1 (relative to a salinity of 34.93) is mainly due to the PW. The net heat transport relative to −0.1°C is northward, but undergoes a rapid northward decrease, suggesting an area-averaged surface heat loss of 50–100 W m−2 in the strait. 相似文献
13.
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
14.
Wind-induced Kuroshio intrusion into the South China Sea 总被引：14，自引：0，他引：14
The Kuroshio flows north along the east coasts of the Philippines and Taiwan. Between these two land masses lies the Luzon Strait which connects the Pacific Ocean to the South China Sea. The Kuroshio usually flows north past this strait, but at times part or all of it flows west through the strait into the South China Sea forming a loop current. It has been suggested that the loop current forms when the northeast monsoon deflects the Kuroshio through the Luzon Strait. In this study, satellite-derived sea-surface temperature images are used to observe the Kuroshio in the Luzon Strait region. Together with wind data from the region, these observations indicate a loop-current development process which is largely determined by an integrated supercritical wind stress parameter. The loop current grows when a four-day average of the local wind-stress component directed to the south exceeds 0.08 Nm–2. When this average wind-stress component drops below the critical value, the Kuroshio returns to its northward path. 相似文献
15.
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
16.
B. N. Filyushkin S. N. Moshonkin S. A. Myslenkov V. B. Zalesnyi N. G. Kozhelupova 《Oceanology》2013,53(6):643-654
The character of the water exchange in the Denmark Strait for the period of 1958–2006 is studied based on the results of the numerical experiments using the model of the ocean circulation developed at the Institute of Numerical Mathematics of the Russian Academy of Sciences with a resolution of 0.25 degrees in latitude and longitude with 27 vertical levels. The calculations were performed for the North Atlantic area from 30° S, including the Arctic Ocean and the Bering Sea. The width of the Denmark Strait at 66° N is about 650 km, and the depth is approximately 550 m. The fields of the temperature, salinity, and density and the components of the current velocities were simulated. In this period, the average overflow of dense waters with the conventional potential density σ0 > 27.80 to the North Atlantic through the Denmark Strait was 1.86 ± 0.96 Sv, and, for the nearbottom and intermediate waters with σ0 > 27.50, it was 3.84 ± 1.31 Sv. The maximum values of the overflow transport through the strait were recorded in 1962, 1972, 1983, 1990, and 2000. Exactly these years showed the highest values of the North Atlantic oscillation (NAO) index. This fact confirms the domination of the decadal variability of the hydrogeological processes in the North Atlantic. The model section of the current velocity through the strait showed the occurrence of at least four well marked jets that vertically occupy the entire sectional area from the surface to the bottom. The two jets divided by a northward jet at the strait’s middle move southward along the Greenland slope. The northward current along Iceland is also identified. This structure of the currents is also supported by the analysis of the observed variability of the absolute topography of the ocean’s surface. 相似文献
17.
Recent investigation suggests that volume transport through the Tsushima/Korea Strait often has double peaks during the summer
to autumn period with decreasing transport in September. The satellite-observed wind changes from weak northwestward (across-strait)
in summer to strong southwestward (along-strait) in early autumn (September) in the strait. Such a strong along-strait wind
is related to tropical cyclones, which frequently pass through the East China Sea in September. The effect of the along-strait
wind component on the transport variation is examined using a three-dimensional numerical model. The simulated volume transport
through the Tsushima/Korea Strait shows realistic seasonal and intra-seasonal variations. According to sensitivity experiments
on local winds, the transport variations in September are mainly generated by strong along-strait (southwestward) wind rather
than weak across-strait wind. The strait transport responds to the along-strait wind (southeastward), which produces a sea
level increase along the Korean coast, resulting in the geostrophic balance across the strait. The transport minimum through
the Tsushima/Korea Strait in September can be determined by the combination of the across-strait geostrophic and along-strait
ageostrophic balances.
The Editor-in-Chief does not recommend the usage of the term “Japan/East Sea” in place of “Sea of Japan”. 相似文献
18.
南海南部与外海间的体积和热、盐输运及其对印尼贯穿流的贡献 总被引：11，自引：1，他引：11
根据中国近海高分辨率 ( 1 / 6°)环流模式的模拟结果 ,计算了南沙邻近海域与外海之间的海水体积、热量和盐量输运及其对印度尼西亚贯穿流的贡献。研究海域为 0°— 1 4°N的整个南海南部海域。计算得出 ,穿过研究海域流向印度尼西亚海域 ,最终流向印度洋的年平均体积、热量和盐量输运分别为 5 .2Sv( 1Sv =1× 1 0 6m3·s- 1 )、0 .5 7PW和 1 84Gg·s- 1 ,大约占印度尼西亚贯穿流相应输运量的 1 / 4。这一结果表明南海是全球大传送带这一全球海洋最主要热盐环流系统的重要通道之一。从南海流向印度尼西亚海域的通道以卡里马塔海峡为最主要 ,以下依次为巴拉巴克海峡、民都洛海峡和马六甲海峡。大的南向通量主要发生在冬、秋季 ,春末夏初总的通量向北。计算还得出输入本海区的热输运量比输出少 0 .0 64PW ,由这一结果推得 ,通过海 -气界面由大气进入海洋的年平均净热通量约为 30W·m- 2 。 相似文献