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1.
Surface current field and seasonal variability in the Kuroshio and adjacent regions derived from satellite-tracked drifter data 总被引：7，自引：2，他引：5
The muhiyear averaged surface current field and seasonal variability in the Kuroshio and adjacent regions are studied. The data used are trajectories and （1/4） ° latitude by （1/4） ° longitude mean currents derived from 323 Argos drifters deployed by Chinese institutions and world ocean circulation experiment from 1979 to 2003. The results show that the Kuroshio surface path adapts well to the western boundary topography and exhibits six great turnings. The branching occurs frequently near anticyclonic turnings rather than near cyclonic ones. In the Luzon Strait, the surface water intrusion into the South China Sea occurs only in fall and winter. The Kuroshio surface path east of Taiwan, China appears nearly as straight lines in summer, fall, and winter, when anticyclonic eddies coexist on its right side; while the path may cyclonically turning in spring when no eddy exists. The Kuroshio intrusion northeast of Taiwan often occurs in fall and winter, but not in summer. The running direction, width and velocity of the middle segment of the Kuroshio surface currents in the East China Sea vary seasonally. The northward intrusion of the Kuroshio surface water southwest of Kyushu occurs in spring and fall, but not in summer. The northmost position of the Kuroshio surface path southwest of Kyushu occurs in fall, but never goes beyond 31 °N. The northward surface current east of the Ryukyu Islands exists only along Okinawa-Amami Islands from spring to fall. In particular, it appears as an arm of an anti- cyclonic eddy in fall. 相似文献
2.
In the Xiangshan Bay at the east coast of China, coastal marine pollution is conspicuous and severe in recent years. As transport of the pollutants is closely related to the coastal circulation, there is a great practical significance to investigate the circulation in this area. In this work, the surface pattern and vertical profiles of Lagrangian residual velocity (LRV) were studied based on field observation data from the inner Xiangshan Bay. By tracking GPS-GPRS drifters’ trajectories, the surface LRV pattern is going out in the central deep trough and flowing inwards near the shoreside. Combined with data from two mooring stations, vertical profiles of LRV is flowing out at surface and flowing in at the bottom, consistent with the gravitational circulation induced by baroclinic effects at the estuary. However, according to the diagnostic analysis, the main mechanism driving the residual current is barotropic rather than baroclinic. The LRV equation is controlled by the tidally-averaged barotropic pressure gradient force, tidal body force and tidally-averaged turbulent stress, while the tidally-averaged baroclinic pressure gradient force is one order of magnitude less than other forces. Additionally, the tidally mean eddy viscosity coefficient which is used in the expression of tidally-averaged turbulent stress might be not adequate and requires further studies. 相似文献
3.
Argos漂流浮标的若干观测结果 总被引：4，自引：0，他引：4
表层漂流浮标是一种利用Argos卫星系统定位与传送数据的海洋观测设备,它可以利用Lagrangian法则连续观测表层海流及表层水温。文章利用近年在南海和西太平洋投放的部分卫星跟踪表层漂流浮标所取得的观测资料,分析观测海域的表层海流特征及其漂移路径上的温度变化,得出以下结果。(1)由浮标的漂移轨迹看出,黑潮表层流路年际变异相当大。(2)2003年1月,黑潮表层水有入侵南海的趋势,似无西北太平洋表层水深入南海的迹象;夏季南海表层水由南海流出经吕宋海峡汇入黑潮主干。(3)秋季台湾东北海区存在一个强反气旋涡,空间尺度约270km。(4)黑潮主干在秋末冬初经过东海时明显呈弯曲流动,并形成许多小尺度的气旋式涡。(5)在九州西南海域,黑潮表层流并无分支北上进入对马暖流区。(6)2003年春季,黑潮在日本以南的弯曲不明显,并伴随有冷、暖涡产生,暖涡的强度和空间尺度都要比冷涡大得多。(7)由漂流浮标观测得到的的表层海水的温度分布明显呈日变化和季节变化的特征。在浮标漂移路径呈反气旋或气旋式转动的区域,表层水温对应出现高或低温区;但出现在台湾以东的低温区则与此时期的台风过境有关。 相似文献
4.
Alexander B. Rabinovich Richard E. Thomson Steven J. Bograd 《Journal of Oceanography》2002,58(5):661-671
Hydrographic surveys and satellite imaging reveal that mesoscale anticyclonic (AC) eddies are common features of the area
south of Bussol' Strait, the deepest of the Kuril straits connecting the western North Pacific and Sea of Okhotsk. To examine
the velocity structure of these eddies, we deployed groups of 15-m drogued satellite-tracked surface drifters over the Kuril-Kamchatka
Trench in the fall of 1990 and late summer of 1993. Drifters in both groups entered large AC eddies centered over the axis
of the trench seaward of Bussol' Strait and subsequently underwent a slow northeastward translation. One drifter (Drifter
1315) deployed near the center of the “Bussol' eddy” in 1990, remained in the eddy for roughly 45 days and made five loops
at successively greater distances from the eddy center. Large-amplitude (80–100 cm/s) storm-generated inertial oscillations
were observed during the first two loops. The vorticity field associated with the eddy resulted in a Doppler “red-shift” of
inertial frequency motions such that the “effective” inertial period of 21 hours was roughly 4 hours greater than the nominal
inertial period for the drifter latitude (45°N). In 1993, a second drifter (Drifter 15371) was retained in the Bussol' eddy
for about 40 days. This eddy had characteristics similar to those of the 1990 eddy but was devoid of significant high-frequency
motions until the drifter's final half loop. The observed spatial scales, persistence, and slow poleward translation of the
eddies suggests that they play an important role in the dynamics of the East Kamchatka and Oyashio current systems.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
5.
Priyantha Jinadasa Sinhalage Uday Pathirana Gayan Ranasinghe Pradeep Nalak Centurioni Lu Hormann Verena 《海洋学报(英文版)》2020,39(3):103-112
Monsoon driven water mass exchange between the Bay of Bengal(Bo B) and Arabian Sea(AS) is the common experience. However, it is not yet firmly confirmed that the exchange pathway is either passing through southern tip of Sri Lanka or Palk Strait. Local circulation patterns impact the pathways followed by the East Indian Coastal Currents(EICC) that drive exchange, thereby modulating mixing and water mass transformation in the Bay of Bengal around Sri Lanka. In this study, observations from surface drifters were incorporated with the satellite derived data to understand the monsoonal impact on circulation patterns in the Indian Ocean. This was the first multi-national scientific effort which was conducted in the Bo B and AS during 2013 to 2015 to understand the monsoonal impact on circulation patterns in the complex region. The results indicated that seasonally reversing monsoonal currents of southern Sri Lanka, traced by the wintertime freshwater export pathways of the EICC. The deflection of monsoon currents running along the east coast of Sri Lanka by forming cyclonic and anti-cyclonic eddies, which influence the mixing and stirring associated with these flows. Results further indicate the low salinity cold water flows from the Bo B to AS along the western boundary of the Bo B during northeast monsoon. In the same way, reverses the phenomena during southwest monsoon, transporting high salinity warm water from AS to the Bo B. This maintain the bay status which occurred due to freshwater influx from large rivers and high saline water from AS. However, no evidences were observed for the exchange through Palk Strait during the study.Also, there are some mis-matches in in-situ and remotely sensed measurements which imply the necessity of systematic observation system for the complex region as an alternative approach. 相似文献
6.
越南离岸流跨海盆特征初步分析 总被引：3，自引：0，他引：3
为了更加清晰地分析南海的环流结构,本文利用南海表层卫星跟踪漂流浮标轨迹,结合卫星高度计资料,分析了南海中、南部跨海盆尺度海流。结果表明,2011年9~10月,越南沿岸流向南,并分别在11.5°N和8.5°N(等深线出现弯曲处)转向东形成越南离岸流。之后,这支离岸流在11°~16°N呈现蛇形路径,从越南东岸跨越南海南部海盆到达菲律宾西岸。分析卫星高度计数据,结果表明,秋季南海中北部被气旋式环流控制,气旋式环流南部为东向流,可从越南东部一直到菲律宾沿岸,从而决定了越南离岸流跨海盆的特征。越南离岸流的蛇形路径主要是由反气旋-气旋-反气旋-气旋交错出现的中尺度涡决定的。 相似文献
7.
8.
The East Central climate division of Louisiana is used as a case study to evaluate relationships between divisional climate data and the 15 largest flood events on each of seven rivers during a 25-year period. Monthly precipitation and moisture surplus (a water-budget component) are correlated with number of rivers in flood within the division; the Palmer Drought Severity Index (PDSI) is not. Although divisional data sets index climatic variability for nearly 100 years, this study indicates that some cautions should be considered when applying divisional data to flood analyses. [Key words: water budget, PDSI, climate division data, flooding, storm precipitation.] 相似文献
9.
Four drift bottles, cast adrift south of the Subtropical Convergence at 48°S, 156°E in November 1980, landed within 123 days of release at a short stretch of coast north of Banks Peninsula. A high degree of coherence in the responsible drift pattern is indicated. The contemporary surface circulation inferred from satellite‐derived sea‐surface temperature distributions indicates that the bottles were entrained in a meridionally‐converging flow after drifting across the southern Tasman Sea without crossing the Convergence. They were prevented from further eastward drifting because of a marked southward flexing of the Convergence east of the Southland Current during February 1981. Because of local weather and tide effects, the bottles finally beached in Pegasus Bay. 相似文献
10.
Lagrangian drifters, moored acoustic Doppler current meters and hydrographic observations are combined with wind observations to describe the mean and variable nature of flow around Kapiti Island, New Zealand. Thirteen day-long deployments of up to six Lagrangian drifters show the mean flow is to the southwest, with evidence of stronger flows in the channel separating the island from the mainland, and an island wake in the lee of the island. Vortices in this island wake may be tidally driven. Scaling considerations suggest the flow is strong enough that tidal-generated vortices are shed on each tidal cycle. Both the drifters and mooring data suggest that the d’Urville Current around Kapiti Island has a significant wind-driven component. During north-westerlies, the drifters tend to hug the coast, and south-eastwards flows in the Rauoterangi Channel are accelerated. We suggest the observed correlation is the local expression of a South Taranaki basin scale response to the winds. 相似文献