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1.
This study investigates atmospheric responses to the directions of surface wind over the Kuroshio front in the East China Sea, using wintertime satellite-derived data sets. Composite maps of sea surface temperature, wind speed, precipitation, turbulent heat flux, surface wind divergence, and the curl of wind vectors above the atmospheric boundary layer are depicted based on the classification of intense northeasterly (along the front) and northwesterly (across the front) winds over the East China Sea. When northeasterly winds prevail, considerable precipitation occurs on the offshore side of the Kuroshio front, in contrast to periods when northwesterly winds prevail. First, the northeasterly winds strengthen above the front because of the downward transfer of momentum from the fast-moving air at higher levels and/or an adjustment of sea level pressure over the oceanic front, although the process by which the influence of the Kuroshio penetrates beyond the marine atmospheric boundary layer remains unclear. Second, a cyclonic vortex forms above the marine atmospheric boundary layer (at 850-hPa height) on the offshore side of the front, and thereafter, surface wind convergence via Ekman suction (hence, enhanced precipitation) occurs over the East China Sea shelf breaks. The northeasterly winds blow over the East China Sea when the Aleutian Low retreats to the east and when high sea level pressure covers the northern Sea of Japan. 相似文献
2.
东海陆架环流季节变化的模拟与分析 总被引：12，自引：2，他引：10
在改进POM模式基础上,建立1个中国东部海域斜压准预报模式,利用全球海洋模式结果并结合实测资料以及高精度卫星遥感SST资料,进行了东海陆架海域温盐及环流年循环的数值模拟,并系统分析了东海陆架环流系统及其季节变化、各暖流的路径等广为关注的问题。模式结果表明：黑潮主轴主体沿陆架坡折走向,中段黑潮流幅由南至北增宽,流速变大,流核所达深度变浅。浙闽沿岸流是一典型的季风环流,台湾暖流终年表现出东、北两分支结构,其分支表现出明显的季节性变化特征。在东海东北部陆架海域,冬季黑潮以其分支形式向北入侵,夏季则主要以大陆边缘流的形式向北进入陆架。论文对各暖流的水源也进行了相应的分析。 相似文献
3.
Winter appearance of a northeastward warm current off the southern coast of China against gale force winds is well documented but lacks a plausible explanation. Relaxation of northeasterly winds is envisaged here as a possible cause of the South China Sea Warm Current in winter. A three-dimensional circulation model for the South China Sea is first driven to equilibrium by climatological forcings. Thereafter, wind forcing is relaxed from the 15th day of each month for 9 days. In winterlike months from December to April, the wind relaxation invariably triggers a northeastward current of which the location and alongshore span are comparable to that of the observed warm current. This current is driven by the pressure gradient along the northwestern boundary of the South China Sea, sea level being high to the southwest and low to the northeast. The sea level gradient is built up by the monsoon-driven southwestward coastal current along the northwestern boundary and, after wind relaxes, triggers a return current and a sea level drop that expand southwestward from the southern coast of China to the east coast of Vietnam. The current is initially barotropic, becoming increasingly baroclinic in time as warm waters from the south are advected northeastward. The model also suggests that the sea level gradient is present in most of the months of the year, but is not as dramatic as in winter to trigger fundamental changes in the circulation of the South China Sea. 相似文献
4.
I~IOXThe northern South China Sea is the frontal region for the water exchange between the sleuthChina Sea (SCS) and its neighboring seas. Its northeast part connects to the East China hothrough the Taiwan Strait and the east part ~ates with the Pacific Ocean by the LUZOn Strait.The a~heric interface over the northern SCS is the important paSSage for the South China Seamourn. Therefore, the uPPer vallationS Of the northern SCS are not Only affected by the dynndc and thermed~c d… 相似文献
5.
Seasonal and spatial distributions of phytoplankton biomass associated with monsoon and oceanic environments in the South China Sea 总被引：5，自引：3，他引：2
Seasonal variations of phytoplankton/chlorophyll-a （Chl-a） distribution, sea surface wind, sea height anomaly, sea surface temperature and other oceanic environments for long periods are analyzed in the South China Sea （SCS）, especially in the two typical regions off the east coast of Vietnam and off the northwest coast of Luzon, using remote sensing data and other oceanographic data. The results show that seasonal and spatial distributions of phytoplankton biomass in the SCS are primarily influenced by the monsoon winds and oceanic environments. Off the east coast of Vietnam, Chl-a concentration is a peak in August, a jet shape extending into the interior SCS, which is associated with strong southwesterly monsoon winds, the coastal upwetling induced by offshore Ekman transport and the strong offshore current in the western SCS. In December, high Chl-a concentration appears in the upwelling region off the northwest coast of Luzon and spreads southwestward. Strong mixing by the strong northeasterly monsoon winds, the cyclonic circulation, southwestward coastal currents and river discharge have impacts on distribution of phytoplankton, so that the high phytoplankton biomass extends from the coastal areas over the northern SCS to the entire SCS in winter. These research activities could be important for revealing spatial and temporal patterns of phytoplankton and their interactions with physical environments in the SCS. 相似文献
6.
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
7.
南海海面高度季节变化的数值模拟 总被引：8，自引：1，他引：8
比较POM模式模拟与观测(TOPEX/Poseidon高度计资料)的南海海面高度(SSH)的季节变化在空间分布上的一致性和差异.结果表明:本文使用的POM模式能较好地模拟南海SSH的季节变化;冬季与夏季,春季与秋季南海海面异常场形式完全相反,冬季Ekman输运造成在西海岸的堆积要比夏季在东海岸堆积更明显,而吕宋冷涡中心附近和吕宋海峡海面季节变化振幅最大;除春季以外,在南海绝大部分海域,海面高度的季节变化主要受风力的控制,南海海面热量通量对SSH的季节变化贡献约为20%,风应力对SSH的季节变化的贡献约为80%. 相似文献
8.
自然环境特征对海洋开发建设有着重要影响,为了更好地为21世纪海上丝绸之路建设提供科学依据,文章重点对南海、孟加拉湾、阿拉伯海三大海域的地理概况、气候特征进行系统性统计分析。结果表明,该海域的风场、风浪、表层海流受季风影响明显,其中阿拉伯海和孟加拉湾受西南季风的影响更为明显,冬季风的影响次之,南海则相反。阿拉伯海的热带气旋主要活动于其东侧,孟加拉湾则在其中东部区域,南海主要是北部海域受热带气旋影响明显。南海—北印度洋的能见度整体乐观。夏季降水明显多于冬季,夏季大值区分布于印度半岛西部近海、孟加拉湾东北部、马尼拉西部区域。 相似文献
9.
Characteristics of Sea Surface Circulation and Eddy Field in the South China Sea Revealed by Satellite Altimetric Data 总被引：4，自引：0，他引：4
Temporal and spatial variations of sea surface circulation in the South China Sea were revealed with use of altimetric data provided by TOPEX/POSEIDON from December 1992 to October 1997. The estimated distribution of sea surface dynamic heights from altimetric data coincide well with the results of observation by Soong et al. (1995) and Chu et al. (1998). The RMS variability of sea surface dynamic height, which is obtained after tidal correction based on Yanagi et al. (1997), is high in the central part of the South China Sea, the Gulf of Tongking, the Sunda Shelf and the Gulf of Thailand. The high RMS variability in the Gulf of Tongking, the Sunda Shelf and the Gulf of Thailand is due to set up and set down of sea water by the East Asian monsoon, which is northeasterly during winter and southwesterly during summer. Also, the high RMS variability in the central part of the South China Sea is due to the variations of basin-wide circulation. The circulations are dominant in the central part of the South China Sea during summer and winter, an anticyclonic circulation during summer and a cyclonic circulation during winter. It is suggested that these circulations are controlled by the East Asian monsoon. Hence, there is an interannual variability of the basin-wide circulation associated with the variation of the East Asian monsoon. 相似文献
10.
冬季黄海暖流西偏机理数值探讨 总被引：1，自引：0，他引：1
利用海洋数值模式(MITgcm)模拟了冬季黄海流场并对冬季黄海暖流西偏的机理进行了探讨。冬季黄海流场模拟试验表明,黄海暖流由济州岛以西约32.5°N,125°E附近进入黄海,然后沿着黄海深槽西侧70 m等深线附近向北偏西运动;海面高度调整对黄海暖流路径具有重要影响,沿着黄海暖流路径的海面高度梯度比周围海区大,由海面高度梯度产生的地转流引起的北向体积输运占总的北向体积输运的78%。狭长海湾地形控制试验表明,单纯的黄海地形分布不足以引起黄海暖流西偏。黄海典型断面试验与渤海、黄海、东海地形控制试验说明,黄海暖流进入黄海的地理位置对流场分布有重要影响,黄海暖流进入黄海的位置恰好位于深槽西侧地形坡度较大区域,在位涡守恒的约束下黄海暖流受地形捕获沿70 m等深线附近向北偏西运动;试验还表明,黄海暖流进入黄海的位置与东海北部环流和地形分布有关,在冬季风的作用下东海北部环流的一部分沿着地形陡坡进入黄海形成黄海暖流。由此认为,黄海、东海环流在其特殊地形的约束下对冬季风的响应和调整,是引起黄海暖流西偏的主要原因。 相似文献
11.
1988—2009年中国海波候、风候统计分析 总被引：3，自引：0，他引：3
利用高精度、高时空分辨率、长时间序列的CCMP(Cross-Calibrated,Multi-Platform)风场,驱动国际先进的第三代海浪模式WAVEWATCH-Ⅲ(WW3),得到中国海1988年1月～2009年12月的海浪场。对中国海的波候(风候)进行精细化的统计分析,分析了海表风场和浪场的季节特征、极值风速与极值波高、风力等级频率和浪级频率、海表风速和波高的逐年变化趋势,结果显示:(1)中国海的海浪场与海表风场具有较好的一致性,尤其是在DJF(December,January,February)期间;海表风速和波高在MAM(March,April,May)期间为全年最低,在DJF期间达到全年最大;MAM和JJA(June,July,August)期间,中国海大部分海域的波周期在3～5.5s,SON(September,October,November)和DJF期间为4.5～6.5s。(2)中国海极值风速、极值波高的大值区分布于渤海中部海域、琉球群岛附近海域和台湾以东广阔洋面、台湾海峡、东沙群岛附近海域、北部湾海域、中沙群岛南部海域。(3)吕宋海峡在MAM、SON、DJF期间均为6级以上大风和4m以上大浪的相对高频海域,JJA期间,6级以上大风的高频海域位于中国南半岛东南部海域,4m以上大浪主要出现在10°N以北。(4)在近22a期间,中国海大部分海域的海表风速、有效波高呈显著性逐年线性递增趋势,风速递增趋势约0.06～0.15m.s-1.a-1,波高递增趋势约0.005～0.03m.a-1。 相似文献
12.
为了探讨海洋表层沉积物的孢粉分布与可能陆源地区植被、气候以及孢粉传播机制的关系,为南海古环境研究提供可靠的基础,采用野外取样、室内实验、计算孢粉百分比和孢粉浓度等方法,对广东沿海及海南岛东南部(108°34′12″—120°E,17°—23°43′12″N,水深为37—3370m)40个表层沉积物样品进行孢粉分析,揭示表层孢粉在整个广东沿海及海南岛东南部的分布和传播规律,尤其关注以往未涉及的广东沿岸海域的孢粉分布情况。研究发现草本花粉如禾本科Poaceae、蒿属Artemisia、藜科Chenopodiaceae、十字花科Brassiceae除在广东沿海近岸带含量较高外,一般都低,可能与沿岸热带亚热带草地分布以及水稻、甘蔗、蔬菜种植有关,推测是以冬季表层环流为动力由北向南传播的。松属Pinus花粉百分比高(20%)且传播较远,以珠江口和东沙群岛附近的样点最高,向西南逐渐降低,说明松属花粉是以冬季风为主要动力传播的。近海区域表层沉积的芒箕孢子含量很高(60%),可能与剧烈的人类活动干扰有关。而热带、亚热带阔叶林花粉(如栲属和栎属)的数量却远远低于其在陆地植被中的数量。广东沿岸的栲属Castanopsis、栎属Quercus、三缝孢Trilete-spore等花粉主要来源于海南岛和广东沿岸,可能是随河流及南海北部表层环流输送的。单缝孢及水生植物莎草科Cyperaceae的百分含量以靠近珠江口的样点较高,可能与河流的注入有关。 相似文献
13.
SMOS卫星盐度数据在中国近岸海域的准确度评估 总被引：3，自引：3，他引：0
盐度是描述海洋的关键变量,对海表面盐度进行观测可以推进对全球水循环的理解。本文的主要目的是在中国近海海域对SMOS卫星盐度数据进行准确度评估。主要方法是将SMOS卫星L2海洋盐度数据产品(V317)与实测ARGO数据和走航数据进行匹配,并采用统计学的方法对SMOS卫星数据准确度进行评估。结果表明:匹配数据的线性关系不显著,SMOS卫星盐度数据(V317)在南海和东海的均方根误差分别约为1.2和0.7,应用海表面粗糙度修正模型得到的3组海表盐度数据准确度都相对较低,尤其在近岸强风场区域,海表盐度卫星数据相对于实测数据偏高,这可能是由于海表粗糙度和陆地射频干扰(RFI)作用影响的结果;SMOS卫星数据在东海的均方根误差比南海高0.5左右,这可能是由于东海海域为相对开阔海域,受陆地RFI影响相对南海较小;在中国近岸海域,应用SSS1和SSS3模型得到的盐度数据准确度相对较高,可以对模型进行地球物理参数修正,进行局地化改进,预计可以提高近岸海域盐度反演的准确度。 相似文献
14.
Numerical experiments were performed in order to investigate the effects of variations of the transport through the Korea/Tsushima Strait, an inlet of the Japan/East Sea, on the upper layer circulation in the JES based on a 10-month transport observation from May 1999 to March 2000 (Perkins et al., 2000). All external forcings to the model were annual mean fields, except the transport variation through the Korea Strait. In the experiments where the periodic variation of the transport repeated continuously sinusoidally by several periods, strong variability of sea surface height (SSH) was detected in the region extending from the Korea Strait to the Japanese coast due to the geostrophy of the buoyancy forcing at the Korea Strait. The region along the Korean coast is more sensitive to the long-term variations than the short-term (≤60-day period) ones. In two experiments forced by realistic and monthly mean transport, the difference of rms of sea surface height was largest at the Japanese coast and relatively large at the East Korean Warm Current separation region (128∼130°E, 39∼41°N) and to the east of Yamato Rise. The distribution of difference of eddy kinetic energy at 100 m depth between the two experiments was similar to that of the rms of SSH. In the distributions of mean SSH and mean kinetic energy at 100 m depth the realistic transport invokes eddy variability to interact with mean current resulting in the changes of the mean SSH and the mean kinetic energy at the East Korean Warm Current separation region, but it does not produce conspicuous changes in the mean fields of entire JES compared with the mean fields forced by the seasonal transport. 相似文献
15.
A high-resolution, regional, numerical-model-based, real-time ocean prediction system for the northern South China Sea, called the Northern South China Sea Nowcast/Forecast System (NSCSNFS), has been used to investigate subtidal mesoscale flows during the time period of the Asian Seas International Acoustic Experiment (ASIAEX) field programs. The dynamics are dominated by three influences; 1) surface wind stress, 2) intrusions of the Kuroshio through Luzon Strait, and 3) the large-scale cyclonic gyre that occupies much of the northern South China Sea. Each component primarily drives currents in the upper ocean, so deep currents are rather weak. Wind stress is especially effective at forcing currents over the shallow China shelf. The Kuroshio intrusion tends to flow westward until it meets the northern edge of the large-scale cyclonic gyre. Together, these currents produce an intense, narrow jet directed northwest toward the continental slope, often in the region of the ASIAEX field programs. Upon reaching the slope, the current splits with part flowing northeastward along the slope and part flowing southwestward, producing large horizontal and vertical shears and making this region dynamically very complicated and difficult to simulate. The Kuroshio intrusion tends to be stronger (weaker) when the northeasterly winds are strong (weak) and the large-scale gyre is farther south (north), consistent with conclusions from previous model studies. At the northern boundary, the model produces a persistent northward flow through Taiwan Strait into the East China Sea. Data assimilation in the NSCSNFS model is shown to dampen the system, extracting energy and causing the entire system to spin down. 相似文献
16.
Response of the cold water mass in the western South China Sea to the wind stress curl associated with the summer monsoon 总被引：3，自引：3，他引：0
1Introduction TheSouthChinaSea(SCS)isasemi enclosed tropicalmarginalseawithcomplextopographyand numerousislands(seeFig.1)andtheonlydeep channelbetweentheSCSandtheadjacentPhilippine SeaistheLuzonStrait.TheclimateoftheSCSis controlledbytheEastAsianmonsoonsy… 相似文献
17.
18.
Kuh Kim Yun Bae Kim Jong Jin Park SungHyun Nam Kyung-Ae Park Kyung-Il Chang 《Ocean Science Journal》2005,40(1):25-44
Long-term, continuous, and real-time ocean monitoring has been undertaken in order to evaluate various oceanographic phenomena
and processes in the East/Japan Sea. Recent technical advances combined with our concerted efforts have allowed us to establish
a real-time monitoring system and to accumulate considerable knowledge on what has been taking place in water properties,
current systems, and circulation in the East Sea. We have obtained information on volume transport across the Korea Strait
through cable voltage measurements and continuous temperature and salinity profile data from ARGO floats placed throughout
entire East Sea since 1997. These ARGO float data have been utilized to estimate deep current, inertial kinetic energy, and
changes in water mass, especially in the northern East Sea. We have also developed the East Sea Real-time Ocean Buoy (ESROB)
in coastal regions and made continual improvements till it has evolved into the most up-to-date and effective monitoring system
as a result of remarkable technical progress in data communication systems. Atmospheric and oceanic measurements by ESROB
have contributed to the recognition of coastal wind variability, current fluctuations, and internal waves near and off the
eastern coast of Korea. Long-term current meter moorings have been in operation since 1996 between Ulleungdo and Dokdo to
monitor the interbasin deep water exchanges between the Japanese and Ulleung Basins. In addition, remotely sensed satellite
data could facilitate the investigation of atmospheric and oceanic surface conditions such as sea surface temperature (SST),
sea surface height, near-surface winds, oceanic color, surface roughness, and so on. These satellite data revealed surface
frontal structures with a fairly good spatial resolution, seasonal cycle of SST, atmospheric wind forcing, geostrophic current
anomalies, and biogeochemical processes associated with physical forcing and processes. Since the East Sea has been recognized
as a natural laboratory for global oceanic changes and a clue to abrupt climate change, we aim at constructing a 4-D continuous
real-time monitoring system, over a decade at least, using the most advanced techniques to understand a variety of oceanic
processes in the East Sea. 相似文献
19.
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
20.
《Deep Sea Research Part I: Oceanographic Research Papers》2003,50(7):917-926
Time-longitude diagrams of monthly anomalies of TOPEX/Poseidon sea surface height (SSH), Levitus steric height, COADS wind stress curl, as well as meridional surface wind averaged over the northern South China Sea (SCS) from 18° to 22°N, exhibit a coherent westward phase propagation, with a westward propagation speed of about 5 cm s−1. The consistency between oceanic and atmospheric variables indicates that there is a forced Rossby wave in the northern SCS. The horizontal patterns of monthly SSH anomalies from observations and model sensitivity experiments show that the forced Rossby wave, originating to the northwest off Luzon Island, actually propagates west-northwestward towards the Guangdong coast because of zonal migration of the meridional surface wind. The winter Luzon Cold Eddy (LCE), which has been found from field observations, can be identified as a forced Rossby wave with a negative SSH anomaly in winter. It corresponds to strong upwelling and a negative temperature anomaly. Sensitivity experiments show that the wind forcing controls the generation of the LCE, while the Kuroshio is of minor importance. 相似文献