The inter-annual variability of the Yellow Sea Warm Current surface axis and its influencing factors

Based on the Pathfinder sea surface temperature(PFSST),the surface axis and its pattern of the Yellow Sea Warm Current(YSWC) are discussed.A structure of double-warm-tongue is found in February and it varies in different years.Two indexes are calculated to represent the westward shift(WSI) and northward extension(NEI) of the warm water in the Yellow Sea(YS).Wavelet analysis illustrates that the WSI and NEI have prominent periods of 3-6 years and 3-4 years,respectively.The Empirical Orthogonal Function(EOF) decomposition is applied to the winter wind stress curl and the Kuroshio Current(KC) transport,which are believed to play important roles in forcing the variability of the YSWC surface axis.Statistics shows that the WSI is significantly related with the second EOF mode of the wind stress curl in February,which may force the YSWC surface axis moving westward and maintaining the double warm tongues because of its opposite curl in the YSWC domain.The first EOF mode of wind stress curl in January is propitious for inducing the warm tongue in the YS to advance more northward.Hence,the wind stress curls both in January and in February could force variations of the YSWC surface axis;however,the effect of the January wind stress curl is relatively weaker than that of the February.The relationship between the NEI and the KC transport is remarkable,and it seems that the stronger KC supplies more power to push the YSWC northward against the southward wind.

Observational evidence of the Yellow Sea warm current

The Yellow Sea Warm Current (YSWC) is one of the principal currents in the Yellow Sea in winter. Former examinations on current activity in the Yellow Sea have not observed a stable YSWC because of the positioning of current meters. To further understand the YSWC, a research cruise in the southern Yellow Sea was carried out in the winter of 2006/2007. Five moorings with bottom-mounted acoustic Doppler current profilers (ADCP) were deployed on the western side of the central trough of the Yellow Sea. The existence and distributional features of the YSWC were studied by analyzing three ADCP moorings in the path of the YSWC in conjunction with conductivity-temperature-depth (CTD) data over the observed area in the southern Yellow Sea. The results show the following. (1) The upper layer of the YSWC is strongly influenced by winter cold surge; its direction and speed often vary along a south-north axis when strong cold surges arrive from the north. (2) The YSWC near the bottom layer is a stable northwest flowing current with a speed of 4 to 10 cm/s. By combining the analyses of the CTD data, we speculate that the core of the YSWC may lie near the bottom. (3) On a monthly average timescale, the YSWC is stably oriented with northward flow from the sea surface to the sea floor.

Winter heat budget in the Huanghai Sea and the effect from Huanghai Warm Current (Yellow Sea Warm Current)

Four sources of surface heat flux （SHF） and the satellite remote sensing sea surface temperature （SST） data are combined to investigate the heat budget closure of the Huanghai Sea （HS） in winter.It is found that heat loss occurs all over the HS during winter and the area averaged heat content change decreases with a rate of-106 W/m 2.Comparing with the area averaged SHF of-150 W/m 2 from the four SHF data sets,it can be concluded that the SHF plays a dominant role in the HS heat budget during winter.In contrast,the heat advection transported by the Huanghai Warm Current （Yellow Sea Warm Current,HWC） accounted for up to 29% of the HS heat content change.Close correlation,especially in February,between the storm events and the SST increase demonstrates that the HWC behaves strongly as a wind-driven compensation current.

Sea surface temperature evolution in the Yellow Sea Warm Current pathway and its teleconnection with high and low latitude forcing during the mid-late Holocene

Sea surface temperature(SST)in the Yellow Sea Warm Current(YSWC)pathway is sensitive to the East Asian Winter Monsoon(EAWM)and YSWC.However,the role of the YSWC in the evolution of regional SST remains unclear.Here,we present new U 37 k′based SST and grain size sequences spanning the last 6092 years in the sediment core Z1,which was retrieved from the central Yellow Sea muddy area.Overall,U 37 k′-SST gradually increased since 6.1 ka BP,with a series of centennial-scale fl uctuations.Its variation was mainly caused by EAWM when YSWC was weak between 6.1 and~3.9 ka BP,as shown by the end-member content of grain size.However,after YSWC was fully developed,i.e.,since~3.9 ka BP,it exerted critical eff ects on SST evolution in its pathway.The 1010-and 538-year cycles of the SST sequence indicated a basic control of solar activity on the oceanic conditions in the Yellow Sea.It is suggested that the variation of total solar irradiance was amplifi ed by thermohaline circulation and then transmitted to the Yellow Sea through the EAWM.Meanwhile,the tropical Pacifi c signal of El Niño was transmitted to the YSWC through the Kuroshio Current.The dual properties of warm water transported by YSWC to compensate the EAWM and driving by Kuroshio Current closely linked the variation of SST in the YSWC pathway to the Northern Hemisphere high latitude climate and the tropical Pacifi c.These fi ndings highlight the signifi cance of YSWC on regional SST evolution and its teleconnection to high and low latitude forcing,which grains a better understanding of the long-term evolution of SST in the middle latitude Yellow Sea.

Characteristics of zooplankton community in North Yellow Sea unveiled an indicator species for the Yellow Sea Warm Current in winter: Euchaeta plana

Zooplankton distributions are largely influenced by both biotic and abiotic factors in the surrounding environment.Some zooplankton species can be used as bio-indicators for particular currents and water masses to help discover the dynamics of water current in the ocean.In this study,we investigated the distribution of zooplankton in North Yellow Sea(NYS)during winter when the Yellow Sea Warm Current(YSWC)influenced that area.Zooplankton communities in the NYS were dominated by temperate and warm-temperate species,such as Calanus sinicus,Paracalanus parvus,Acartia bifilosa,and Sagitta crassa.Two warm-water species,Eucheata plana and Sagitta enflata were also present.Cluster analysis grouped NYS zooplankton into three communities,the Shandong Coastal Community(SCC)in the Shandong neritic area,the Yellow Sea Central Community(YSCC)in the central waters of the NYS,and the Liaoning Coastal Community(LCC)in the Liaoning neritic area.Abundances varied significantly among these communities,with an average of 102.2 ind./m^3 in SCC,179.8 ind./m^3 in YSCC,and 1244.2 ind./m^3 in LCC.Depth and the bottom(3 m from the sea floor)temperature were likely the primary abiotic factors influencing zooplankton distributions.The appearance of E.plana,an indicator species for the YSWC path,indicated a significant northwestward trend for the YSWC in 2007.

THE STUDY OF THE YELLOW SEA WARM CURRENT AND ITS SEASONAL VARIABILITY

The Yellow Sea Warm Current （YSWC） penetrates northward along the Yellow Sea Trough, and brings warm and saline water towards the Bohai Sea. The YSWC becomes much less intrusive in summer and is limited mostly in the southern trough, contrasting with a deep winter penetration well into the trough. The seasonal variability of the YSWC has prompted a debate regarding which controls the YSWC and its seasonal variability. In this article, the annual mean and seasonal variability of the YSWC was examined by using a 3-D ocean model together with several experiments. The results show that in the annual mean the YSWC is a compensating current firstly for the southward Korea Coastal Current （KCC）, which is mainly caused by the Kuroshio Current （KC）. The local wind-stress forcing plays an important but secondary role. However, the local monsoonal forcing plays a prominent role in modulating the seasonal variability. A deep northwestward intrusion of the YSWC in winter, for instance, is mainly due to a robustly developed China Coastal Current （CCC） which draws water along the Yellow Sea trough to feed a southward flow all the way from the Bohai Sea to the Taiwan Strait.

Sea surface temperature records of core ZY2 from the central mud area in the South Yellow Sea during last 6200 years and related effect of the Yellow Sea Warm Current

Sea surface temperature (SST) records in the South Yellow Sea during the last 6200 years are reconstructed by the unsaturation index of long-chain alkenones (K 37 U ') in sediment core ZY2 from the central mud area.The SST records varied between 14.1 and 16.5°C (15.6°C on average),with 3 phases:(1) A high SST phase at 6.2-5.9 cal ka BP;(2) A low and intensely fluctuating SST phase at 5.9-2.3 cal ka BP;and (3) A high and stable SST phase since 2.3 cal ka BP.Variation of the SST records is similar to intensity of the Kuroshio Current (KC),and corresponds well in time to global cold climate events.However,the amplitude of the SST response to cooling events was significantly different in different phases.The SST response to global cooling event was weak while the KC was strong;and the SST response was strong while the KC was weak.The difference in amplitude of the SST response is possibly caused by the modulation effect of the Yellow Sea Warm Current which acts as a shelf branch of the KC and a compensating current induced by the East Asia winter monsoon.The warm waters brought by the Yellow Sea Warm Current cushion the SST decrease induced by climate cooling,and both the Kuroshio and East Asian winter monsoon play important roles in the modulation mechanism.The SST records display a periodicity of 1482 years.The same period was found in the KC records,indicating that variation of the SST records in the central South Yellow Sea is strongly affected by KC intensity.The same period was also found in Greenland ice cores and North Atlantic and Arabian Sea sediment cores,showing a regional response of marine environmental variability in the East China Seas to that in the global oceans.

Existence, morphology and structure of the Yellow Sea Warm Current Branch approaching waters offshore Qingdao, China

In this study, we focused on full-region cruise survey data, near-bottom continuous mooring observations and sea surface wind products from the western South Yellow Sea in winter; after ensuring the data reliability and accuracy, we processed and analyzed the data. Image resolution experiments were carried out to determine the lowest recognition resolutions for all image types, which represent the resolution characteristics of the data. The existence of a warm water tongue originating from the Yellow Sea Warm Current(YSWC) that approached waters offshore Qingdao was confirmed. For the first time, a high salinity water tongue, corresponding to the warm water tongue, was described and found to be more representative of the YSWC branch path. This warm tongue is a sign of the branch originating from the YSWC, which we defined as the Yellow Sea Warm Current Branch approaching waters offshore Qingdao(YSWC-QDB). The pattern of the warm and salty water tongues showed remarkable rear, branching middle, shrinking neck and expanding top regions. These patterns showed a temporal feature of the tongues, and were the result of multi-temporal branches in front of the YSWC main section as well as the YSWC-QDB crossing the southwestward path of the extension of the North Shandong Coastal Current flowing along the southeast coast of the Shandong Peninsula(NSCC-SESE). Analysis using mooring data at a sensitive and representative station also showed the existence of the YSWC-QDB. It is a probabilistic event that manifests as a northwestward flow that decreases gradually from the bottom to the surface in the early cold air transit stage and consistent in the whole water column profile in the later stage. It varies quasi-periodically with weather processes. It also transports some of the YSWC water stored in the entrance area of the Bohai and Yellow seas under winter wind conditions to the western South Yellow Sea as a compensatory current. This current, caused by northerly winds, especially northwest winds and obstruction of the NSCC-SESE, was present, and strong water reduction and compensation caused significant residual sea level oscillations. The compensatory current, if caused by strong northwest wind,began to appear when its direction was opposite to the wind direction. In addition, confirmation of the YSWC-QDB provides an oceanographic basis for the short cooling time and rapid warming in the Qingdao area in winter. This research provides a basis for further studies of the YSWC-QDB at high spatial and temporal resolutions using large sea surface datasets. For monsoon basin dynamics, this study can also be extended to the whole Bohai and Yellow seas and closed or semi-closed basins on the continental margin.

Long-Chain Alkenones in the South Yellow Sea Sediments and Their Indicative Significance for Haptophytes Species

Long-chain alkenones(LCAs)have been widely used as important biomarkers in palaeoceanographic studies.However,the commonly used LCAs proxies are mainly based on C_(37) alkenones,and it is still lack of the studies about the distribution and in-dications of LCAs with different chain lengths other than C_(37) alkenones.Here,the composition and distribution of LCAs were ana-lyzed in surface sediments from the southern Yellow Sea(SYS)and a sedimentary core(A02-C)from the central Yellow Sea(YS)mud area.The results showed that C_(37),C_(38) and C_(39) alkenones were the major LCAs in surface sediments of the SYS,and the relative contents of C_(38:2)Et,C_(37:2)Me,C_(37:3)Me,C_(38:2)Me,C_(38:3)Et,C_(38:3)Me,C_(39:2)Et and C_(39:3)Et were 18.3%-59.8%,22.6%-41.2%,7.4%-23.0%,6.6%-15.4%,3.8%-13.3%,3.6%-8.7%,2.8%-6.0% and 0.7%-3.0%,respectively.Then the relationships of U_(38Me)^(K)-U_(38Et)^(K) and U_(37)^(K')-U_(38Et)^(K) indicate that LCAs are mainly derived from Emiliania huxleyi(E.huxleyi).High ratios of total C_(37) alkenones to total C_(38) alkenones(K_(37)/K_(38))(1-1.2)were found in the central SYS,corresponding to the relatively high abundance of E.huxleyi;while low ratios of K_(37)/K_(38)(0.7-0.9)were observed at nearshore area of the SYS where Gephyrocapsa oceanica(G.oceanica)has rela-tively high abundance.The spatial distribution of K_(37)/K_(38) ratio is also consistent with that of coccolithophores nannofossil in the sediments.In addition,K_(37)/K_(38) ratio in core A02-C varied from 0.7 to 1.1 with a gradual decreasing trend during the past 5.5 kyr.This suggests that the relative abundance of E.huxleyi decreased gradually,caused by the changes in the Yellow Sea Warm Current(YSWC)and the East Asian Winter Monsoon(EAWM)during this period.

Seasonal evolution of the Northern Yellow Sea cold water mass

With the in-situ temperature and salinity observations taken seasonally in the Northern Yellow Sea area during the National 908 Water Investigation and Research Project from 2006 to 2007, the characteristics of the Northern Yellow Sea cold water mass （NYSCWM） were studied, including both its spatial pattern over the whole bottom and historically typical section from Dalian to Chengshantou. Seasonal evolution as well as its spatial distribution was analyzed to further understand the NYSCWM, as a result, some new features about the NYSCWM had been found. Compared to the previous studies, the center of colder water mass in summer moved eastward, but sharing the similar peak values for both temperature and salinity with historical data. In spring, the axis of 32.8 psu saltier moves westward approximately 75 km and the high salinity areas beyond 123.5° E were largely impaired comparing to that in winter. In winter, the NYSCWM almost disappeared due to the reinforced wind-induced mixing and the Yellow Sea Warm Currents （YSWC） moved northward and controlled most of the Northern Yellow Sea region. In autumn, two cold centers with the peak value of 9℃ were found inside the attenuated NYSCWM.

Biomarker Records of Phytoplankton Productivity and Community Structure Changes in the Central Yellow Sea Mud Area During the Mid-Late Holocene

The Yellow Sea （YS） environmental and ecological changes during the Holocene are driven by the interactions between the Yellow Sea Warm Current （YSWC）, the East Asian Winter Monsoon （EAWM） and the Kuroshio Current （KC）. We report marine biomarker records of brassicasterol, dinosterol and C37 alkenones in core ZY1 and core ZY2 from the South Yellow Sea （SYS） to reconstruct the spatial/temporal variations and possible mechanisms of phytoplankton primary productivity and community structure changes during the Mid-late Holocene. The contents of the corresponding biomarkers in the two cores are similar, and they also reveal broadly similar temporal trends. From 6kyr to 3kyr, the biomarker contents in the two cores were relatively low with small oscillations, followed by a distinct increase at about 3 kyr indicating productivity increases caused by a stronger EAWM. The alkenone/brassicasterol ratio （A/B） is used as a community structure proxy, which also showed higher values in both cores since 3 kyr, indicating increased haptophyte contribution to total productivity. It is proposed that the YS community structure has been mainly influenced by the YSWC, with stronger YSWC influences causing an increase in haptophyte contribution since 3 kyr. Some differences of the biomarker records between ZY2 and ZYI suggest spatial variations in response to YSWC and KC forcing. When the KC was intensified during the periods of 6-4.2kyr and 1.7-0kyr, the YSWC extended eastward, exerting more influence on core ZY1. On the other hand, when the KC weakened during 4.2-1.7 kyr, the YSWC extended westward, exerting more influence on the ZY2.

An N-shape thermal front in the western South Yellow Sea in winter

An N-shape thermal front in the western South Yellow Sea （YS） in winter was detected using Advanced Very High Resolution Radiation （AVHRR） Sea Surface Temperature data and in-situ observations with a merged front-detecting method. The front, which exists from late October through early March, consists of western and eastern wings extending roughly along the northeast-southwest isobaths with a southeastward middle segment across the 20--50 m isobaths. There are north and south inflexions connecting the middle segment with the western and eastern wings, respectively. The middle segment gradually moves southwestward from November through February with its length increasing from 62 km to 107 km and the southern inflexion moving from 36.2°N to 35.3°N. A cold tongue is found to coexist with the N-shape front, and is carried by the coastal jet penetrating southward from the tip of the Shandong Peninsula into the western South YS as revealed by a numerical simulation. After departing from the coast, the jet flows as an anti-cyclonic recirculation below 10 m depth, trapping warmer water originally carried by the compensating Yellow Sea Warm Current （YSWC）. A northwestward fowing branch of the YSWC is also found on the lowest level south of the front. The N-shape front initially forms between the cold tongue and warm water involved in the subsurface anti-cyclonical recirculation and extends upwards to the surface through vertical advection and mixing. Correlation analyses reveal that northerly and easterly winds tend to be favorable to the formation and extension of the N-shape front probably through strengthening of the coastal jet and shifting the YSWC pathway eastward, respectively.

Simulation and analysis on seasonal variability of average salinity in the Yellow Sea

The CTD (conductivity, temperature and depth) data collected by six China-Korea joint cruises during 1996-1998 and the climatological data suggest that the seasonal variability of average salinity in the Yellow Sea (Sa) presents a general sinusoid pattern. To study the mechanism of the variability, annual cycles of Sa were simulated and a theoretical analysis based on the governing equations was reported.Three main factors are responsible for the variability: the Yellow Sea Warm Current (YSWC), the Changji-ang (Yangtze) River diluted water (YRDW) and the evaporation minus precipitation (E-P). From December to the next May, the variability of Sa is mainly controlled by the salt transportation of the YSWC. But in early July, the YSWC is overtaken and replaced by the YRDW which then becomes the most important controller in summer. From late September to November, the E-P gradually took the lead. The mass exchange north of the 37癗 line is not significant.

Recent improvements to the physical model of the Bohai Sea,the Yellow Sea and the East China Sea Operational Oceanography Forecasting System

In order to satisfy the increasing demand for the marine forecasting capacity,the Bohai Sea,the Yellow Sea and the East China Sea Operational Oceanography Forecasting System(BYEOFS)has been upgraded and improved to Version 2.0.Based on the Regional Ocean Modeling System(ROMS),a series of comparative experiments were conducted during the improvement process,including correcting topography,changing sea surface atmospheric forcing mode,adjusting open boundary conditions,and considering atmospheric pressure correction.(1)After the topography correction,the volume transport and meridional velocity maximum of Yellow Sea Warm Current increase obviously and the unreasonable bending of its axis around 36.1°N,123.5°E disappears.(2)After the change of sea surface forcing mode,an effective negative feedback mechanism is formed between predicted sea surface temperature(SST)by the ocean model and sea surface radiation fluxes fields.The simulation errors of SST decreased significantly,and the annual average of root-mean-square error(RMSE)decreased by about 18%.(3)The change of the eastern lateral boundary condition of baroclinic velocity from mixed Radiation-Nudging to Clamped makes the unreasonable westward current in Tsushima Strait disappear.(4)The adding of mean sea level pressure correction option which forms the mean sea level gradient from the Bohai Sea and the Yellow Sea to the western Pacific in winter and autumn is helpful to increasing the fluctuation of SLA and outflow of the Yellow Sea when the cold high air pressure system controls the Yellow Sea area.

Features of Clay Minerals in the YSDP102 Core on the Continental Shelf of the Southeast Yellow Sea

Ninety-eight clay mineral samples from the YSDP102 core were analyzed by x-ray diffractometer to study the four clay minerals: illite, chlorite, kaolinite and smectite. Twenty-eight samples had been analyzed on the laser particle-size analyzer to reveal the particle features of the sediments. Distribution of the clay minerals and the particle characteristics in the YSDP102 core show that the core experienced three different depositional periods and formed three different sedimentary intervals due to different sediment sources and different depositional environments. Features of the clay minerals and the heavy minerals in the YSDP102 core indicate that coarse-grained sediments and fine-grained sediments result from different sources. The Yellow Sea Warm Current has greatly influenced the sedimentary framework of this region since the current’s formation.

Case analysis of water exchange between the Bohai and Yellow Seas in response to high winds in winter

Based on the data from a special project titled China's Offshore Marine Integrated Investigation and Evaluation as well as Regional Ocean Modeling Systems(ROMS)diagnostic numerical model,we studied the influence of high wind processes on the circulation and water exchange between the Bohai and Yellow Seas(BYS)in winter.The results show that the vertical structure of the Yellow Sea Warm Current(YSWC)is relatively uniform under condition of high winds,showing obvious barotropic features.However,this flow is not a stable mean flow,showing strong paroxysmal and reciprocating characteristics.A comparison of the changes in sea level suggests that the intensity of the northwards upwind flow is consistent with the abnormal fluctuations in the sea level.It indicates that the upwind flow is closely related to the water exchange between the BYS.The impact of high wind processes on the water exchange between the BYS is enormous.It can make the flux through the Bohai Strait,as well as that through the mouth of each constituent bay(i.e.,Liaodong Bay,Bohai Bay,and Laizhou Bay)far greater than usual,resulting in a significant increase in the water exchange rate.The exchange capacity,which is about 8%of the total volume of the Bohai Sea,can be completed in a few days.Therefore,the water exchange of the Bohai Sea may be completed by only a few occasional high wind processes in winter.

Responses of Primary Productivity to Current and Climate Changes in the Mud Area to the Southwest of Cheju Island During the Past 800 Years

The biogenic silica (BSi) ,total organic carbon (TOC) ,total nitrogen (TN) and grain size were analyzed with a gravity core (3250-6) collected from the mud area in the north East China Sea.The average deposition rate of the upper core was about 0.078cm yr1based on the results of 210Pbex.The mean grain size increased with depth in general.The frequency distribution of grain size showed that two marked changes of deposition environment occurred at 30 cm and 50 cm depths (about 1550 AD and 1300 AD,respectively) .The variations of BSi and TOC indicated two distinct major periods of primary productivity over the past 800 years:a stage of low primary productivity corresponding to weak upwelling and low nutrient input below 30 cm depth (about 1200-1550 AD) ,and a stage of high primary productivity with strong currents and upwelling above 30 cm depth (about 1550-1950 AD) .The stage with high primary productive appeared to be due to the northward-expanded muddy area caused by strong Asian Winter Monsoon and enhanced Yellow Sea Warm Current in winter.In conclusion,the BSi and TOC in the muddy sediments,the symbols of marine primary productivity,can be then used to investigate the evolution history of currents and relative climate change in the offshore areas.

北黄海温盐分布季节变化特征分析

利用2006～2007年夏冬春秋4个季节北黄海的大面调查资料，分析了4个季节北黄海温度和盐度大面以及典型断面分布特征，得出以下结论：2007年冷水团势力范围强于2006年，北黄海冷水团的形成受地形影响。黄海暖流冬春季较强，冬季最强，夏季最弱，秋季开始形成。鲁北沿岸流冬季最强，春季减弱，夏秋季消失，但夏季鲁北沿岸存在冬季鲁北沿岸流水的残余体，即鲁北沿岸水。辽南沿岸水4个季节都以低盐为特征，除夏季低盐中心位于庄河口外，其它3个季节低盐中心均位于调查区域的东北角。渤海与北黄海之间的水交换4个季节都存在。春季，断面盐跃层形成滞后于温跃层；秋季，断面盐跃层消失滞后于温跃层。

末次冰消期以来东黄海暖流系统的演化

以黑潮为主干的东黄海暖流系统，所携带的高温高盐水对我国近海的海洋环境和大气环流格局产生了重大影响。为系统重建由黑潮暖流、对马暖流和黄海暖流组成的东黄海暖流系统在末次冰消期以来的演化过程，建立末次冰消期以来东黄海暖流系统的演化模式，对取自黑潮主流轴附近的DGKS9603孔、现代对马暖流边缘的CSH1孔和与黄海暖流相伴生的冷水体下面的泥质沉积区YSDP102孔的古海洋记录进行综合分析研究。结果表明，现代东黄海暖流系统是伴随着末次冰消期以来黑潮的演化和海平面的脉冲式上升而形成与演化的，地理边界条件是非常重要的控制因素。16kaB．P．黑潮对冲绳海槽的影响开始加强，之后随着海平面的上升，对马暖流开始发育，到8．5kaB．P．左右，现代对马暖流正式形成，期间黑潮暖流经历了Heinrich 1和Younger Dryas事件的两次减弱过程。7—6kaB．P．是黑潮暖流和对马暖流末次冰消期以来最强盛的时期；约6．4kaB．P．左右黄海暖流开始出现，至此东黄海暖流系统的基本格局已完全形成；在5．3—2．8kaB．P．期间，冲绳海槽发生了以“Pulleniatina低值事件”为标志的黑潮变弱过程，导致对马暖流主流轴在3kaB．P．左右发生了一次向太平洋方向的偏转事件，低温、高营养物质含量的陆架冷水团对冲绳海槽北部影响加强，期间在黄海暖流附近冷水体下面堆积了巨厚的泥质沉积体系。此后，由黑潮暖流、对马暖流和黄海暖流组成的东黄海暖流系统显著加强，直至达到现代的态势。

近岸强海流切变锋作用下悬浮沉积物的输送和沉积——以山东半岛东端外海为例

利用2007年国家908专项ST02区块(渤海海峡及北黄海)水体专项夏季和冬季两个航次调查的温度、浊度和悬浮体浓度数据,选取了跨越山东半岛东端外海泥质沉积体的B1和B2两个断面,结合该区浅地层剖面资料,辅以研究海域的冬季环流数值模拟,着重分析了山东半岛东端外海强海流切变锋作用下的悬浮体输送和沉积特征。结果表明山东半岛东端外海悬浮体向外海输送存在类似"夏储冬输"的规律:夏季,北黄海海水浊度普遍小,不仅北黄海温跃层抑制了底层悬浮体向中上层水体扩散,而且北黄海冷水团在中底层与山东半岛东部沿岸水也形成了显著的温度和悬浮体锋面,阻碍了悬浮物的纬向输送,故夏季应是悬浮体沉积的主要时节;冬季,温跃层消亡,在强风的作用下,山东半岛东部悬浮体浓度高且垂向混合较好,然而在泥质沉积体顶积层两侧,山东半岛东部沿岸中下层北上的逆风补偿流和北上的黄海暖流与位于顶积层上方表中层南下的沿岸流构成了两道显著的强海流切变锋,使得底积层上大量的再悬浮沉积物不能越过山东半岛东部陆架末梢,从而有助于形成山东半岛东端外海特有的Ω状泥质沉积体。