Numerical Study of Water and Suspended Matter Exchange Between the Yellow Sea and the East China Sea

INTRODUCTIONTheYellowSeaandtheEastChinaSea (ECS)aremarginalseasofthenorthwestPacificandhaveexpansivecontinentalshelves .TheuniqueandstrikingfeaturesoftheYellowSeaandtheECSarethattheyhavestrongtidalcurrent;aresubjecttostrongmonsooninfluence ;andreceiveinflowfromthebiggestriverinChina ,theChangjiangRiver ;andthatthefamouswesternboundarycurrent,theKuroshio ,passesthroughtheECS ,withitsbranchesintrudingupwardintothecontinentalshelfareas.Generallyspeaking ,thewaterexchangecapacityofthe…     

A probe heat flow value of the East China Sea shelf

Bottom temperature variation (BTV) is a serious problem in determining the thermal gradient and heart flow of the sediments in shallow seas. The water depth of the East China Sea shelf is mostly below 150m, and the heat flow measurement is strongly affected by BTV. Following a statistical algorithm, we rechecked the temperature and thermal conductivity data of the cruises KX90-1 and KX91-1, carried out by a cooperation program of China and Japan, and calculate the heat flow in a site without long-term temperature record. The calculated heat flow in the site was 58.6±3.6 mW/m², being just within the range of the drill heat flow value of East China Sea shelf. The inversed amplitude spectrum of BTV has a peak in frequency of 1/10 per year, and the annual component is also an important part. Comparison with two lakes of Lake Greifensee and Lac Leman (i.e. Lake Geneva), which are in different water depth, revealed that with increasing water depth, the peak of amplitude spectrum moved towards low frequency components. The heat flow values calculated in this paper and from petroleum bore hole in East China Sea shelf are much more close to that in southeast China than in Okinawa Trough. Supported by the National High Technology R&D Program of China (2004 AA616060)     

Characteristics of Light Transmission in Summer and Winter and Its Relation on Sediment Transport in the East China Sea

Light transmission data collected from June to July 1987 and from February to March 1997 by the R/V Kexue 1 in the East China Sea were used to analyze its distribution characteristics and its relation to the sediment transport in this sea. Some results obtained were: (1) The Taiwan Warm Current flowing northwards seemed to be a barrier preventing suspended matter discharged from the Changjiang River Estuary from continuously moving southeastward and causing the suspended matter to flow along a path near 123°30′E in summer and 123°00′E in winter. (2) Suspended matter in the area adjacent to the Changjiang River Estuary could not be transported southward along the coast in summer due to opposing offshore currents including the Taiwan Warm Current flowing northward and the Changjiang Diluted Water turning northeastward. (3) The thermocline and temperature front bar suspended matter from crossing through.     

Characteristics of Light Transmission in Summer and Winter and Its Relation to Sediment Transport in the East China Sea

INTRODUCTIONTheSubeiShoalandtheChangjiangRiverestuarineareainthewestoftheHuanghaiandEastChinaSeasisoneofthemarginalseasintheworld ,wheresuspendedmatterisextremelyhigh .Here ,notonlyistheretheTaiwanWarmCurrentoneoftheKuroshio’sbranchesintheEastChinaSea,butalsotheHuanghaiCoastalCurrent,andChangjiangDilutedWater.Sothestrongmixingbetweenthecoastalandoffshorewaterscomplicatessuspendedmatterdistributioninthisarea.HowthesuspendedmatterdischargedfromtheChangjiangRiverandtheabandonedHuan…     

Vertical structure of the tidal currents on the continental shelf of the East China Sea

The available data on tidal currents spanning periods greater than six months for the continental shelf of the East China Sea (26°30.052′N, 122°35.998′E) were analyzed using several methods. Tidal Current Harmonic Analysis results demonstrated that semi-diurnal tides dominated the current movement. The tidal currents of the principal diurnal and semidiurnal rotated clockwise with depth, with the deflection of the major semi-axes to the right in the upper layer and to the left in the lower layer. The vertical structures of two principal semi-diurnal constituents-M2 and S2-were similar, which indicates that the tidal currents are mainly barotropic in this area. The main features of the variation of the four principal tidal constituents with depth demonstrate that the currents in this region are influenced by the upper and lower boundary layers. Therefore, the tidal constituents of the shallow water are similar. Different vertical modes were calculated based on the Empirical Orthogonal Function (EOF) analysis of the Eastern and Northern components of the tidal currents, with a variance contribution for the zero-order model of at least 90%. The variance contribution of the baroclinic model is minimal, which further reveals a strong barotropic character for the tidal currents of this region.     

Temporal-Spatial Variation of Surface Suspended Matter and Controlling Factors in the Inner Shelf of the East China Sea in Winter

Based on the observed surface suspended matter in the East China Sea in February 2007 and June 2015, an empirical model was established using L1 b's band 4 data to retrieve surface suspended matter from the Moderate Resolution Imagine Spectroradiometer Terra imagery. The squared correlation coefficient is 0.8358, and the root mean square error is 0.4285 mg L-1. The model reflects the distribution characteristics of surface suspended matter in the inner shelf of the East China Sea. In this paper, the satellite images of the study area were retrieved in January from 2001 to 2015, and the monthly distribution of surface suspended matter were obtained. The inter-annual distribution of the study area is similar, and the concentration of surface suspended matter is higher near the shore than offshore. A large amount of surface suspended matter is transported southeast under the influence of Zhejiang and Fujian coastal current and Taiwan warm current. Only a small amount of surface suspension can reach the Kuroshio area. The surface suspended matter concentration changes obviously near the estuary because of the effect of differences in the flux of the Yangtze River. Meanwhile, winter monsoon, temperature front, El Ni?o events, and other factors affect the distribution of surface suspended matter in 100 m isobath to coastal water but minimally influence the distribution in 100 m isobath to deep sea.     

Paleo-fluvial sedimentation on the outer shelf of the East China Sea during the last glacial maximum

Evidence from lithology, foraminiferal assemblages, and high-resolution X-ray fluorescence scanning data of core SFK-1 indicates tidally influenced paleo-fluvial sedimentation during the last glacial maximum (LGM) on the outer shelf of the East China Sea. The paleo-fluvial deposits consist of river channel facies and estuarine incised-valley-filling facies. Different reflections on the seismic profile across core SFK-1 suggest that the river channels shifted and overlapped. River channel deposition formed early in the LGM when sea level fell and the estuary extended to the outer shelf. Channel sediments are yellowish-brown in color and rich in foraminifera and shell fragments owing to the strong tidal influence. Following the LGM, the paleo-river mouth retreated and regressive deposition of estuarine and incised-valley-filling facies with an erosion base occurred. The river channel facies and estuarine incised-valley-filling facies have clearly different sedimentary characteristics and provenances. The depositional environment of the paleoriver system on the wide shelf was reconstructed from the foraminiferal assemblages, CaCO₃ content and Ca/Ti ratio. The main results of this study provide further substantial constraints on the recognition of late Quaternary stratigraphy and land-sea interactions on the ECS shelf.     

pCO2 distribution and CO2 flux on the inner continental shelf of the East China Sea during summer 2011

Measurements of pH,total alkalinity(TA),partial pressure of CO2(pCO2) and air-sea CO2 flux(FCO2) were conducted for the inner continental shelf of the East China Sea(ECS) during August 2011.Variations in pCO2 distribution and FCO2 magnitude during the construction of the Three Gorges Dam(TGD)(2003-2009),and the potential effects of the TGD on the air-sea CO2 exchange were examined.Results showed that the ECS acts as an overall CO2 sink during summer,with pCO2 ranging from 107 to 585 μatm and an average FCO2 of-6.39 mmol/(m2·d).Low pCO2(<350 μatm) levels were observed at the central shelf(28°-32°N,123°-125.5°E) where most CO2-absorption occurred.High pCO2(>420 μatm) levels were found in the Changjiang estuary and Hangzhou Bay which acted as the main CO2 source.A negative relationship between pCO2 and salinity(R2=0.722 0) in the estuary zone indicated the predominant effect of the Changjiang Diluted Water(CDW) on the seawater CO2 system,whereas a positive relationship(R2=0.744 8) in the offshore zone revealed the influence of the Taiwan Current Warm Water(TCWW).Together with the historical data,our results indicated that the CO2 sink has shown a shift southwest while FCO2 exhibited dramatic fluctuation during the construction of the TGD,which is located in the middle reaches of the Changjiang.These variations probably reflect fluctuation in the Changjiang runoff,nutrient import,phytoplankton productivity,and sediment input,which are likely to have been caused by the operations of the TGD.Nevertheless,the potential influence of the TGD on the CO2 flux in the ECS is worthy of further study.     

OUTFLOW OF SUSPENDED MATERIALS FROM THE CHANGJIANG RIVER MOUTH

ImODUrmNJ0GFS(JointGlobaldrinFLuxStudy:l99()-2OO()isaworldwidenawhprogramfocusingontheoasns'buharolewhentheC0,prmtageintheairincreasesandtheatmOspheretemPeraturebo.ThefluxofsuspendedrnateriaIs(SM)intheEastChinaScaisboortanttotheworld'srnatterchaltfon,astheChangiiangRiver,thelargestriverinAsia,dischargesbillionsoftOnsoftheidWhterintoit.ManystudAshavebocondtalonSMmovementncarChina'scoastalseas.Yang(l983)studiedthefine%rainedsededtSfromtheChangiiangandHuangheRiversWhileQin(l983)fo…     

Phytoplankton distribution and community structure in the East China Sea (ECS) continental shelf

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The distribution and characteristics of suspended particulate matter in the Chukchi Sea

Samples taken from the Chukchi Sea （CS） during the 4th Chinese National Arctic Research Expedition, 2010, were analyzed to determine the content and composition of suspended particulate matter （SPM） to improve our understanding of the distribution, sources and control factors of the SPM there. The results show that the SPM in the water column is highest in the middle and near the bottom in the south and central-north CS, followed by that off the Alaskan coast and in Barrow Canyon. The SPM content is lowest in the central CS. Scanning electron microscope （SEM） analysis shows that the SPM in the south and central-north CS is composed mainly of diatoms, but the dominant species in those two areas are different. The SPM off the Alaskan coast and in Barrow Canyon is composed mainly of terrigenous material with few bio-skeletal clasts. The distribution of temperature and salinity and the correlation between diatom species in SPM indicate that the diatom dominant SPM in the south CS is from the Pacific Ocean via the Bering Strait in summer. The diatom dominant SPM in the central-north CS is also from Pacific water, which reaches the CS in winter. The SPM in the middle and near the bottom of the water column off the Alaskan coast and in Barrow Canyon is from Alaskan coastal water and terrigenous material transported by rivers in Alaska.     

Study on the seasonal variation of the suspended sediment distribution and transportation in the East China Seas based on SeaWiFS data

The monthly mean suspended sediment concentration in the upper layer of the East China Seas was derived from theretrieval of the monthly binned SeaWiFS Level 3 data during 1998 to 2006.The seasonal variation and spatial distribution of thesuspended sediment concentration in the study area were investigated.It was found that the suspended sediment distribution presentsapparent spatial characteristics and seasonal variations,which are mainly affected by the resuspension and transportation of the sus-pended sediment in the study area.The concentration of suspended sediment is high inshore and low offshore,and river mouths aregenerally high concentration areas.The suspended sediment covers a much wider area in winter than in summer,and for the samesite the concentration is generally higher in winter.In the Yellow and East China Seas the suspended sediment spreads farther to theopen sea in winter than in summer,and May and October are the transitional periods of the extension.Winds,waves,currents,ther-mocline,halocline,pycnocline as well as bottom sediment feature and distribution in the study area are important influencing factorsfor the distribution pattern.If the 10mg L-1 contour line is taken as an indicator,it appears that the transportation of suspended sedi-ment can hardly reach 124°00'E in summer or 126°00'E in winter,which is due to the obstruction of the Taiwan Warm Current andthe Kuroshio Current in the southern Yellow Sea and the East China Sea.     

STUDY OF WATER—TRANSPORT THROUGH SOME MAIN STRAITS IN THE EAST CHINA SEA AND SOUTH CHINA SEA

OCCAM global ocean model results were applied to calculate the monthly water transport through 7 straits around the East China Sea(ECS)and the South china Sea(SCS).Analysis of the features of velocity profiles and their variations in the Togara Strait,Luzon Strait and Eastern Taiwan Strait showed that;1)the velocity profiles had striped pattern in the Eastern Taiwan Strait,where monthly flux varied from 22.4 to 28.1 Sv and annual mean was about 25.8 Sv;2)the profiles of velocity in the Togara Strait were characterized by core structure,and monthly flux varied from 23.3 to 31.4 Sv,with annual mean of about 27.9 Sv;3)water flowed from the SCS to the ECS in the Taiwan Strait,with maximum flux of 3.1 Sv in July and minimum of 0.9 Sv in November;4)the flux in the Tsushima Strait varied by only about 0.4 Sv by season and its annual mean was about 2.3 Sv;5)Kuroshio water flowed into the SCS in the Luzon Strait throughout the year and the velocity profiles were characterized by multi-core structure.The flux in the Luzon Strait was minimun in June(about 2.4 Sv)and maximum in February(about 9.0 Sv),and its annual mean was 4.8 Sv;6)the monthly flux in the Mindoro Strait was maximum in December(3.0 Sv)and minimum in June(Only 0.1 Sv),and its annual mean was 1.3 Sv;7)Karimata Strait water flowed into the SCS from May to August,with maximum in-flow flux of about 0.75 Sv in June and flowed out from September to April at maximum outflow flux of 3.9 Sv in January.The annual mean flux was about 1.35 Sv.     

A review of comminution age method and its potential application in the East China Sea to constrain the time scale of sediment source-to-sink process

The East China Sea(ECS) is a river-dominated epicontinental sea, linking the Asian continent to the northwestern Pacific via the large rivers originating from Tibetan Plateau. The relevant huge influx of riverine detritus has developed unique sedimentary systems in the ECS during the Quaternary, offering ideal terrestrial archives for reconstructing Quaternary paleoenvironmental changes and studying land-sea interactions. Overall, two characteristic river systems dominate the sedimentary systems and sediment source to sink transport patterns in the ECS, represented by the Changjiang(Yangtze River) and Huanghe(Yellow River) for the large river system and Taiwan rivers for the small river system. Given this, the sediments derived from both river systems bear distinct features in terms of parent rock lithology, provenance weathering and sediment transport. Previous studies mostly focus on either the ‘source' discrimination or the ‘sink' records of the sedimentary system in the ECS, while the source to sink process linking the land and sea, in particular its time scale, has been poorly understood. Here we introduce a newly-developed dating technique, the ‘comminution age' method, which offers a quantitative constraint on the time scale of sediment transfer from its ultimate source to the final depositional sink. This novel method is of great significance for improving our understanding on the earth surface processes including tectonic-climate driven weathering, and sediment recycling in relation to landscape evolution and marine environmental changes. The application of comminution age method in the ECS will provide important constraints on sediment source-to-sink process and more evidences for the construction of late Quaternary paleoenvironmental changes under these unique sedimentary systems.     

HETEROTROPHIC BACTERIOPLANKTON PRODUCTION IN THE EAST CHINA SEA

ＩＮＴＲＯＤＵＣＴＩＯＮＭｏｒｅｔｈａｎａｄｅｃａｄｅｈａｓｐａｓｓｅｄｓｉｎｃｅｂａｃｔｅｒｉａｗａｓｒｅｃｏｇｎｉｚｅｄａｓｑｕａｎｔｉｔａｔｉｖｅｌｙｉｍｐｏｒｔａｎｔｃｏｎ ｓｕｍｅｒｓｏｆｏｒｇａｎｉｃｃａｒｂｏｎｉｎｍａｒｉｎｅｆｏｏｄｗｅｂｓａｎｄｍａｒｉｎｅｅｃｏｓｙｓｔｅｍｓ (Ｆｕｈｒｍａｎ ,1 992 ) .ＴｈｅｂａｓｉｃｉｎｆｏｒｍａｔｉｏｎｏｎｔｈｅｓｉｇｎｉｆｉｃａｎｃｅｏｆｔｈｅｍｉｃｒｏｂｉａｌｆｏｏｄｗｅｂｗａｓｐｒｅｓｅｎｔｅｄｂｙＰｏｍｅｒｏｙ ( 1 974 ) ,ｗｈｏｐｉｅ…     

QUANTITATIVE MODELING OF SUSPENDED SEDIMENT IN MIDDLE CHANGJIANG RIVER FROM MODIS

1INTRODUCTIONThe quality of water is traditionally determined by col-lectingwatersamplesandanalyzingthesamplesin a lab-oratory. However, sampling is very much hard sledding,time-consuming, slow and expensive, and easily in thecontrol of weather conditions, and does not include allwater areas. Satellite estimates of water quality havefound widespread application. Remote sensing instru-ments have been applied in water quality monitoringwith varying success (DANA and RICHARD, 1999;RUDD…     

中日东海划界之中间线方案:问题与评析

中日东海划界历经旷日持久而未能解决,中国主张尊重《联合国海洋法公约》(以下简称《公约》)中大陆架之自然延伸原则,采取不同于专属经济区的方法对大陆架进行划界,而日本则始终坚持采用中间线对中日东海大陆架和经济专属区作一揽子划界。无论从逻辑角度还是法理视角,日本主张在中日东海划界中适用中间线将混淆《公约》中专属经济区与大陆架两种制度。基于中日东海大陆架的地质与地貌特点以及公约对上述两种权利的不同规定,中日难以通过中间线对东海的海洋权益作出公平划分。中日两国应以《公约》为依据,分别对专属经济区和大陆架的划界作出安排,同时兼顾处理钓鱼岛群岛的主权归属问题,使中日东海划界问题得到妥善解决。     

DISSOLVED ORGANIC CARBON IN THE EAST CHINA SEA IN AUTUMN

ImODUcrIONThepoolofdissolvedorganicrnatter,eva1uatalasdissolvedorganiccarbonpoC),hasbostudndforrnanyycars(Med,l964,SkopintSevCtal.,l966).Continentalmar-ginshavedrihypotheSedtobeasirnPortanttothemarinecarbonbiogeochdricalCy-desasthedeepsea(Walsh,l99l),butinmostdiscussions,onlyexportofparticulateorganieswasconsidetal.HighconcentIationofDOCincoastalwatershasaspedlroleinexportingcarbonfromcontinentalmarginstotheopenocean.UndelstandingtheroleoftheoceanmarginsintheglobalcarbonCycAsdependsla…     

Dissolved organic matter and its role in red tide succession in the East China Sea in spring

Dissolved fluorescent organic matter was measured using fluorescence excitation-emission matrix spectroscopy at three temporal points during a Synechococcus bloom after diatom bloom dispersion in spring, 2007. Carbohydrate and dissolved organic carbon were also analyzed. The relationship between organic matter and red tide succession was examined. The results show that after the diatom bloom, tyrosine-like fluorescence B intensity was very high within the water column and exhibited a negative correlation wi...     

A THREE-DIMENSIONAL THERMOCLINE MODEL FOR THE YELLOW SEA AND NORTHERN EAST CHINA SEA

A time-dependent, three-dimensional finite difference model is presented for simulating the stratifiedYellow Sea and northem East China Sea. The mode is forced by time-dependent observed wind, surfaceflux of heat, and tidal turbulence. With this model, momentum and temperature distribution can be computed,and an approximation for the sub-grid scale effects is introduced by the use of mass and momentumexchange coefficients. The vertical exchanges are quite dependent on these assumed coefficents, whichare complicated functions of the turbulence energy of tide and wind, of the stratified strength and otherfactors. This model was applied to describe the mechanics of the variations in strength and thickness ofthe thermocline covering almost the whole Yellow Sea and northern East Chna Sea in summer. Comparisonsof the computed output with obtained survey data led to some important conclusions.