wintertime winds and coastal sea level fluctuations in the northeast china sea part ii numerical model abstract as a sequel to data analysis reported in part i a numerical model of the wintertime wind driven circulation of the northeast chine sea is developed with the primary purpose of achieving an understanding of the underlying dynamics to several observed features of the coastal sea level behavior the model is linear and pertains to the vertically integrated balance of momentum and mass in a well mixed shallow ocean the model bathymetry incorporates a realistic shelf embayment and an open ocean region of a depth so limited that observed sea level differences across open boundaries in the deep western pacific do not result in unreasonably large model transports from results of model runs for the 1980 81 winter it is found that 1 along the west coast of south korea sea level setup to the south is a consequence chiefly of the presence at the end of the korean peninsula of relatively deep offshore water that is less responsive to wind forcing than the shallow shelf water 2 pressure gradient forc

a paleoslope model of late albian to early turonian foraminifera of the western atlantic margin and north atlantic basin abstract a paleoslope model of albian to turonian benthic foraminifera reveals seven successive biofacies which are associated with increasing paleodepth the paleoslope model indicates that the biofacies occupied inner neritic to abyssal environments of deposition 10 m to 3500 m water depth biofacies 1 and 2 characterize paleodepths of less than 60 m the biofacies contain abundant species of epistomina and gavelinella and exhibit a rapid stratigraphic alternation in response to local sea level change which considerably aids in the identification of depositional sequences species of globorotalites eggerellina and neobulimina characterize biofacies 3 which principally occurs between 60 m and 130 m paleodepth biofacies 3 is the only biofacies to occur in both the new jersey coastal plain and the baltimore canyon trough biofacies 4 is composed of species of gavelinella gyroidinoides and valvulineria and is abundant in outer neritic to middle bathyal paleodepths of 130 m to 600 m it is largely replaced by biofacies 5 during times of maximum flooding during sea level rise a diverse assemblage of species of lingulogavelinella and lenticulina characterize biofacies 5 paleodepths of 600 m to greater than 3500 m contain abundant species of osangularia pleurostomella praebulimina pseudopatellinella and quadrimorphina which define biofacies 6 and 7 in addition four biofacies of much more limited distribution are recognized biofacies 1 characterizes shallow water open marine paleoenvironments of the north atlantic and is composed of spirillinids and species of epistomina turonian dysaerobic environments are indicated by biofacies dsa and dsb which are composed mostly of agglutinated species dysaerobic environments expanded rapidly from middle bathyal to outer neritic depths in the early turonian on the western atlantic margin biofacies daa represents disturbed benthic environments and is dominated by species of psammosphaera and reophax biostratigraphy and species composition of the studied biofacies are similar to previously described european and south atlantic assemblages major speciation events occur among the genera gavelinella lingulogavelinella and valvulineria well defined neritic and bathyal biofacies formed during a rapid late albian species diversification concomitant with the first major cretaceous flooding of continental margins

recent current observations in the eastern yellow sea observations of current velocity pressure and temperature in the eastern yellow sea from january 10 through april 12 1986 together with geostrophic winds calculated from surface atmospheric pressure distributions are analyzed for a study of the synoptic band response of the yellow sea to the wintertime winds north wind pulses in the winter monsoon are found to give rise to northward flow bursts in the yellow sea trough which appear to peak just as the wind relaxes and to be driven by a synoptic band north to south rise in bottom pressure synchronous with the north wind pulses the existence of a similar rise in coastal sea level indicates that the observed southward pressure rise is but an offshore extension of a setup along the west coast of south korea forced by the north wind pulses the advection by northward flow bursts of warm water from the south apparently causes the measured temperature to be substantially higher in the trough than in coastal waters at the same latitude and the observed rate of cooling in the trough to be less than half of that in coastal waters to the east a winter to spring transition is also found in the bottom pressure records obtained in the trough in which the mean north to south gradient in winter reverses suddenly in early march a similar reversal also appears in sea level records along the west coast of south korea the reversal appears to be triggered by the weakening of the north winds at the arrival of spring

mid cretaceous sequence stratigraphy and sedimentary cyclicity in the western paris basin abstract cenomanian and turonian depositional patterns of the western paris basin are interpreted in terms of sequence stratigraphy a system tract analysis of the epicontinental normandie basin with pelagic chalks and of the maine platform covered by clastics provides evidence for relative changes in coastal onlap various minor uncomformities are related to these changes of sea level the four global cycles uza or zc 2 2 2 5 of haq et al 1987 1988 are recognised while an additional one is proposed for the geslinianum zone in addition periodic rhythmic cycles are commonly registered within the chalk expressed by the repitition of various facies enhanced both by biosedimentary processes and diagenetic alteration these elementary climatic cycles allow accurate lithostratigraphic correlations during this period when the sea level peaked on the tectonically passive border of the armorican block the paris basin appears to record a detailed set of events which can be correlated with those in the atlantic boreal and tethyan provinces

coastal wave generation in the bohai bay and propagation along the chinese coast the bohai bay and yellow sea experience sea surface height ssh changes of 20 cm and larger during wintertime northerly and southerly wind bursts that have a time scale of a few days these large ssh changes give rise to coastal shelf waves that subsequently propagate southward along the chinese coast two models provide observations of these waves the first one is a statistical model based on four years of topex poseidon t p altimeter ssh observations and navy operational global atmospheric prediction system nogaps wind stress fields the second model is a numerical model forced by the wind stress the numerical model provides an objective interpretation of the wind stress response based on dynamical equations the statistical model is based on observations with a linear response to the wind forcing and thus complements the numerical model the observed waves closely resemble gravest mode shelf waves derived by analytical solutions

current observations on the development of the yellow sea warm current historically the climatological mean northward flow in the yellow sea trough has been referred to as the yellow sea warm current yswc since it was thought to originate as a branch of the tsushima current which transports warm kuroshio waters however the tsushima current does not penetrate into the yellow sea interior during winter the onset of what is referred to as the yswc during winter is directly observed using measurements of current profiles pressure and temperature and a wind climatology for the time period july 1995 through january 1996 the yswc is a result of weak southerly winds during summer during fall transition and winter monsoon periods strong northerly wind bursts drive a north to south rise in pressure extending from the trough over to the korean coast and force a northward flow in the yellow sea trough the rise in pressure and corresponding north wind forced yswc begin at the end of october for this measurement period and are observed into january these measurements show that the yswc has different seasonal forcing mechanisms direct current measurements are also presented which suggest a current flow north of cheju sometimes referred to as the cheju warm current

biogeography of planktonic foraminifera and regional carbon isotope variations productivity and water masses in late cretaceous europe the first appearances of species of marginotruncana planktonic foraminifera are found stratigraphically earlier in boreal northwestern germany than in the tethys helvetoglobotruncana helvetica bolli is rare in northwestern germany and common in the tethys its stratigraphic range is probably comparable between both areas the biogeographic patterns are discussed with respect to influences of water depths based on isotope evidence for the depth distribution of species of hedbergella praeglobotruncana and rotalipora and water temperatures the regional variation of 13c values of cenomanian turonian pelagic carbonates was mapped for the european epicontinental basins and the southern european shelf helvetic zone of the alps the highest 13c values up to 5 were found in northwestern germany and the eastern north sea and are coincident with an upwelling zone numerically predicted by three independent climate models intermediate values in france and england 2 4 correspond to predicted weak upwelling lowest values occur in the alpine helvetic zone and the south german regensburg area 1 2 and coincide with predicted absence of upwelling the 13c values are interpreted as indicators of increased biogenic productivity in the upwelling zone semiquantitative nannofossil data suggest abundance patterns influenced by latitude neritic oceanic gradients and productivity observations agree with east to west wind driven surface current systems regional differences in nutrient supply and subsequently different primary productivity could have been a major factor controlling the evolution and the biogeographic distribution of planktonic foraminifera in cenomanian turonian europe

wind driven effects on the yellow sea warm current the yellow sea is a shallow basin writh an average depth of 44 m located between china and the korean peninsula one of the dominant ocean circulation features of the yellow sea is a warm wrater intrusion known as the yellow sea warm current this feature is present throughout the year but reaches its farthest northward extension in winter the circulation of the yellow east china and bohai seas was modeled using the princeton ocean model to better understand the dynamics of the yellow sea warm current the horizontal resolution of the model varies from 8 km in the yellow sea to 25 km in the east china sea twenty four sigma levels are used to define the vertical structure the model uses daily atmospheric forcing from the navy operational global atmospheric prediction system for 1993 open boundary conditions are applied at the taiwan strait the tsushima korea strait an area south of taiwan and the tokara strait with a closed boundary south of the ryukyu islands the model results are examined to determine the effect of the wind on the northward extension of the warm water intrusion using both water mass characteristics and northward velocity components sensitivity tests and spectrum analyses performed to study the influence of the wind on the yellow sea warm current show that winds modify the pathway and extent of the yellow sea warm current the current s origin however appears to be due to external forcing from the current systems developed in the east china sea

an asymmetric upwind flow yellow sea warm current 2 arrested topographic waves in response to the northwesterly wind 1 a warm and salty water mass exists along the yellow sea trough yst in winter this oceanic water mass is distinct from the ambient shelf water and is distributed on the western side of the yst it has long been reasoned that a yellow sea warm current yswc must exist a recent observational study indeed supports the existence of the yswc and shows that its position moved progressively westward as the warm water intrudes further shoreward toward the northwest in this paper we explain mechanisms for sustaining the yswc and for its westward displacement the northwesterly monsoonal wind prevails in the winter and is directed against the yswc the cross trough scale is small compared with the spatial scale of monsoonal variation so one can assume to the first order that the wind stress is uniform across the trough the curl of depth averaged wind stress has opposite signs on the two sides of the trough consequently two oppositely rotating gyres develop initially and they converge along the trough giving rise to a barotropic upwind flow but this upwind flow lasts only for a few days as the two gyres evolve and propagate as topographic waves for a northerly wind both gyres move westward since the positive negative potential vorticity flux on the western eastern side of the trough pushes the water toward shore trough if the bottom friction is negligible the steady response becomes a large anticyclonic gyre over the trough and the upwind current is squeezed toward the shore line in this case no yswc is sustained along or near the trough this runaway warm current can be arrested by a moderate bottom friction we therefore propose that the yswc is actually arrested topographic waves in response to local wind stress forcing

wintertime winds and coastal sea level fluctuations in the northeast china sea part i observations abstract analyses of low pass filtered coastal sea level data and geostrophic winds derived from surface pressure charts for the period of 1 december 1980 through 31 march 1981 indicate that the wintertime dynamics in the northeast china sea is strongly influenced by the passage of rapidly moving cold fronts from northwest to southeast across the region along the west coast of korea sea level fluctuations are highly coherent with the north south wind in two bands centered respectively at about 0 17 and 0 36 cpd and propagate to the south for the low frequency band removal of the wind forced component of the sea level signal yields freely propagating fluctuations in bands centered at about 0 20 0 34 and 0 50 cpd that travel northward at approximately the phase speed expected for barotropic kelvin waves indicative of a relaxation in the sea level field following the successive passages of cold fronts coherence studies of winds and sea level differences in the tsushima strait indicate a correlation

study of the dynamics of wind driven transports into the yellow sea during winter synoptic wind stresses and surface heat flux force a three dimensional numerical ocean model of the yellow sea east china sea dynamics the basin response to winter winds is examined through the model output fields northerly wind bursts are a frequent winter occurrence in this region the wind bursts develop a southward flowing current along the chinese coast as the wind stress forces fluid out of the bohai sea a north south pressure gradient develops as surface water travels from the bohai sea southward decreasing the elevation in the north relative to the elevation in the south also a westward pressure gradient across the yellow sea basin develops in response to the wind forcing the southward pressure gradient forces a bottom flow in the direction opposite to the wind stress this return flow is concentrated in a deep trough located on the eastern side of the basin after the northerly wind ceases the northward transport increases pressure in the north with the result of slowing or stopping the flow northward at times pressure increases in the north sufficiently to force a southward flow in the trough following strong northerly wind events northward transport into the yellow sea occupies the entire trough and may extend into the northern yellow sea bohai sea during periods of calm winds northward flow usually does not penetrate beyond 34 n in the yellow sea this flow is northward on the western side of the island of cheju the flow turns eastward north of cheju and then southward passing through the cheju korea strait the wind stress along the korean coast often deviates from the northerly wind stress over the rest of the yellow sea thus the flow along the korean coast is not as closely related to the northerly wind bursts as the flow along the chinese coast the winter circulation in the yellow sea is predominately a barotropic response to winds with fluctuations due to ekman flow

synoptic variations of residual currents in the huanghe yellow river derived distal mud patch off the shandong peninsula implications for long term sediment transport abstract huanghe yellow river is one of the largest contributors of global terrestrial materials to the sea a large amount of the huanghe derived sediment are responsible for forming not only the nearshore delta depositional system but also a distal mud patch off the shandong peninsula some 350 km east of the present day river mouth to better understand the spatial and temporal variations of sediment dynamics in the distal mud area two field surveys employing the phase averaging method pam were conducted in september 2017 and january 2018 respectively along a 108 km east west transect across the mud patch the residual currents derived from the pam surveys were featured by the southward current in the nearshore area and the northward current in the offshore region in summer while a unidirectional current transported from south to north across the entire transit line in winter these patterns which deviate from the traditional understandings of circulations in magnitude and even in direction are believed to result from episodic wind reversals and associated strengthening and weakening sea level pressure gradients the northerly wind episodes in summer works hand in hand with sea level tilt by preceding southerly wind to enhance the water exchange between the bohai sea and the yellow sea by intensifying both the southward flow along the coast and the northward flow of the south yellow sea water further offshore in winter episodic southerly wind causes relaxation or even reversal of the prevailing winter northerly wind that created the northward sea level tilt in the bohai sea and the yellow sea effectively enhances the south yellow sea water transport to the north yellow sea and the bohai sea consequently a considerable amount of sediment previously exported out of the bohai sea to the mud patch actually return with these backflows since the synoptic time scale oscillations in the bohai and yellow seas are considerably frequent throughout summer and winter the cumulative effects on the long term sediment transport need to be further investigated the observations in this study provide a base for new understanding of how episodic weather events impact the regional circulation and sediment dynamics on the huanghe derived distal mud patch

occurrence of large temperature inversion in the thermohaline frontal zone at the yellow sea entrance in winter and its relation to advection temperature inversion higher temperature at a deeper depth in winter and its relation to advection were investigated by analyzing both conductivity temperature depth data in the southern yellow sea ys and northwestern east china sea during the winter of 2002 2003 and time series data of temperature salinity and currents at a buoy station at the ys entrance significant temperature inversions occur predominantly along the thermohaline front at the ys entrance where the cheju warm current water cwcw and the cold coastal waters meet in february 2003 on the northern frontal zone along 34 n where isotherms and isohalines declined downward to the north particularly large inversions with temperature differences of larger than 2 0 c were observed to occur more in troughs than in the crests of the wave like frontal meander where the cold korean coastal water kcw advances farther southward the inversion persisted until mid april at the buoy station in the frontal zone and both temperature and salinity showed simultaneous variations in the same manner during episodic occurrences of large inversions temperature and salinity decreased sharply in the upper layer but increased concurrently in the lower layer these episodic inversions were found to be closely related to the westward advection of the kcw in the upper layer and the northward advection of the cwcw in the lower layer it is considered that these advections may play an important role in maintaining baroclinicity in the northern frontal zone which is responsible for driving the westward transversal flow across the ys entrance

organic carbon and sedimentation rate further evidence for anoxic deep water conditions in the cenomanian turonian atlantic ocean abstract the relationship between organic carbon content and sedimentation rate based on data derived from recent to miocene sediments deposited under oxic and anoxic sea water conditions is used to characterize the different depositional environments these data are compared with data of cenomanian turonian dsdp sediments from the atlantic ocean the results may support deposition in anoxic environments due to extremely reduced deep water circulation as the main cause for the formation of cenomanian turonian black shales in the north atlantic rather than increased supply of organic matter due to higher oceanic productivity

sea surface height variations in the yellow and east china seas 1 linear response to local wind stress the sea surface height ssh variations observed by the topex poseidon satellite in the yellow and east china seas are examined over the 3 years from 1993 through 1995 assuming a linear response to wind stress across the region the transfer function relating wind stress to ssh is modeled by a series of increasingly complex functions that gradually allow wind stress over successively broader regions and time periods to influence the ssh solution at a particular point the ssh response to instantaneous wind stress at the same point in space implies an ekman transport but the response explains only a small fraction of the ssh variability relating ssh to wind stress averaged over two subregions and including both instantaneous and 12 hour lagged wind stress indicates that a significant portion of ssh variability responds to winds that are remote in both space and time an optimal estimation of the transfer function by minimizing the error variance leads to an extended empirical orthogonal function eeof analysis of the wind stress field the ssh response to each wind mode is determined the analysis shows the principle variations in the wind stress to consist of northerly wind bursts during winter which produce large ssh drops in the bohai bay and northern yellow sea region the principal wind mode also is significantly related to variations along the shelf break near the kuroshio current the third and fourth wind stress modes indicate the passage of typhoons

nutrient fluxes via radium isotopes from the coast to offshore and from the seafloor to upper waters after the 2009 spring bloom in the yellow sea abstract the horizontal and vertical transport of nutrient rich water both from the coast and from the seafloor to the overlying water column should play an important role in supplying nutrients required for the periods of vegetative or reproductive growth of phytoplankton in the present work radium isotopes 223ra 224ra and 226ra in the southern yellow sea were measured after a spring bloom in june 2009 the exponential like decrease of 223ra away from the coast to offshore waters yielded horizontal eddy diffusivities kh of 2 93 1 47 107 cm2 s 1 by neglecting the advection this estimate was smaller than that with advection indicator by as much as 21 when using an analytic model for 223ra and 226ra the corresponding horizontal nutrient fluxes were 1525 mol m 2 d 1 din 15 9 mol m 2 d 1 dip and 826 mol m 2 d 1 dsi which would supply around 16 of n and 3 of p requirements based on the primary productivity the decrease of 224ra and 223ra activities from sediments to the upper water column suggests the vertical eddy diffusion coefficient kz of 6 23 5 58 cm2 s 1 below the thermocline which was within the yellow sea cold water mass yscwm the calculated vertical fluxes of nutrient were 4945 mol m 2 d 1 din 236 mol m 2 d 1 dip and 5315 mol m 2 d 1 dsi accounting for up to 52 of n and 40 of p requirements for the phytoplankton growth these results demonstrate the role of yscwm as a relative nutrient rich pool for the supply of nutrient to the southern yellow sea via the vertical diffusion process relative to the horizontal process during the summer season such processes will be strengthened during the weak density stratification in spring when algal blooms occur

sedimentology and paleontology of a tsunami deposit accompanying the great chilean earthquake of february 2010 abstract at pichilemu in the northern third of the rupture area of the moment magnitude scale mw 8 8 2010 chile earthquake deposits of the tsunami accompanying the earthquake consist of a lower layer of medium to fine sand mean grain size of 200 m containing rock clasts overlain by a thin silty very fine sand mean grain size of 125 m layer based on a sedimentological model most 90 of the deposit is finer than 401 408 m suggesting tsunami flow velocities were between 7 m s and 13 5 m s ostracods were common in the upper layer along with a small number of broken benthic foraminifera and a single planktonic foraminifera diatoms were abundant throughout species assemblages represent a mixture of diatoms from differing environments life forms and substrate preferences we attribute the mixed assemblages to turbulence within the water column during tsunami inundation with erosion of beaches and salt marshes followed by redeposition of sand and mud inland breakage of fragile diatom valves in the lower layer may also support transport by turbulent flow a higher abundance of diatom species with mud substrate preferences in the upper layer implies a decrease in flow velocity from lower to upper layers

cretaceous to eocene sea level fluctuations on the new jersey margin abstract the new jersey margin contains an extensive record of cretaceous to eocene sea level fluctuations these events have been documented on the basis of sedimentology benthic foraminiferal paleobathymetry paleoslope biostratigraphic recognition of unconformities and their associated hiatuses and on seismic reflection records the record of sea level change for the new jersey margin shows a long term second order rise beginning in the upper albian that is punctuated by numerous third order cycles of change in the upper cretaceous paleocene and eocene the sequences deposited during these cycles that are most readily recognizable are separated by type 1 unconformities sequences bracketed by one or two type 2 unconformities are more difficult to resolve although many have been identified sequences shown on the cycle chart of haq et al 1987 of less than 1 ma duration are the most difficult to recognize and many have not been identified in the new jersey section benthic foraminiferal paleoslope studies indicate that relative sea level rise on the new jersey margin varied on the order of 10 120 m above present sea level much of the preserved record in the coastal plain consists of sediments deposited during rising sea level this has led to a stacked record of sea level rise events separated by unconformities

organic rich sedimentation at the cenomanian turonian boundary in oceanic and coastal basins in the north atlantic and tethys one of the most striking results of the deep sea drilling project is the proof that organic rich sediments have a widespread geographical distribution during the period from upper cenomanian to middle turonian such sediments were drilled at north atlantic dsdp sites 105 135 137 138 367 398 551 603 they are also present from outcrops or oil wells on the shelf of the african continental margin senegal tarfaya and agadir basins in the tethys former alboran block southern spain algeria tunisia and umbrian apennines italy and in the north sea although these sediments have different lithologies and depositional environments from shelf areas to the deep sea their study mainly based on organic geochemistry with additional data on sedimentology biostratigraphy and palaeo bathymetry suggests that a unique pulse of organogenic accumulation characterizes the cenomanian turonian boundary event ctbe the content and type of organic matter are related to the depositional environment and organic preservation the organogenic accumulation is distributed according to various trends off the african continental margin the organic content increases from onshore areas to the shelf casamance area and moreover increases also in deep sea areas with a gradual transition from terrestrial type iii to marine type ii the best preservation of the organic matter being in the deepest areas i e site 367 off the american continental margin site 603 shows the same toc and type of organic matter as at site 105 the ctbe is also well recorded in the northern part of the atlantic celtic margin north sea by a drastic lithological change black shales within chalks but the type of organic matter is mainly terrestrial in the tethyan area the organic matter is of marine origin and well preserved results are compared with those of pratt 1984 from the western interior basin of the usa different hypotheses to explain this synchronous widespread accumulation of organic matter are discussed 1986 the geological society

transport reversals at taiwan strait during october and november 1999 1 the observed transport reversals at taiwan strait during october and november 1999 are examined by analytic solutions a numerical ocean model and the prediction from a real time north pacific ocean data assimilating model wind stress explains a majority of the transport reversals the reversals are forced by a combination of the local wind and the remote wind in the yellow and east china seas the connection between the yellow and east china seas wind stress and transport reversals at taiwan strait is provided by coastally trapped waves the waves are generated by the northerly winter wind bursts in the yellow sea and are enhanced in the east china sea by alongshore northerly wind

a numerical study of currents heat advection and sea level fluctuations in the yellow sea in winter 1986 abstract a vertically integrated model that incorporates horizontal temperature variations is used to study the circulation of the yellow sea in a wintertime period for which velocity and temperature measurements are available at several moorings locations along a central trough the model features realistic bottom topography and is forced with wind stress and heat flux fields from 13 january to 22 february 1986 the model also incorporates as a boundary condition sea level fluctuations derived from coastal and insular tide gauge stations along model boundaries in open waters the model reproduces well sea level fluctuations along the coasts of both china and korea the hindcast velocity time series particularly for the north south component track those obtained from direct measurements at the moorings the model momentum balance indicates that the northward flow in the trough is driven by a sea level setup to the south in response to northerly wind bursts in the winter monsoon the sea level fluctuat

sea surface height variations in the yellow and east china seas 2 ssh variability in the weekly and semiweekly bands two types of models are used to examine the sea surface height ssh variability at the principle short time frequency bands in the yellow and east china seas the models are a primitive equation numerical model and a statistical model based on topex poseidon altimeter data in situ pressure gauge measurements at two mooring locations are first used to evaluate each model in addition a comparison of the numerical and statistical models is made through duplicate analysis of the response to the main extended empirical orthogonal function wind stress modes in the northern yellow sea the wind stress pressure gauge data numerical model and statistical model all indicate local spectral maxima in bands centered on the weekly and semiweekly periods the coherence of the two models with the in situ data is significant down to 3 day periods at the northern mooring and down to 5 day periods at the southern mooring the meridional wind stress variability in the semiweekly band is higher than the weekly band energy in the northern yellow sea and bohai bay and lower than the weekly band energy across the east china sea the ssh variability contained in the weekly and semiweekly bands is largest in the bohai bay and northern yellow sea with a region of high energy along the chinese coast the spatial structure of the weekly and semiweekly ssh variability is similar to the wind stress variability at these bands with semiweekly variability higher in the bohai bay and northern yellow sea and weekly variability dominant in the east china sea

computation methods of major tidal currents from satellite tracked drifter positions with application to the yellow and east china seas 1 two practical techniques of correction method and fitting method for computing major diurnal and semidiurnal tidal currents from irregular satellite tracked drifter position data have been developed and then applied to the yellow and east china seas to compute m2 and k1 currents the correction method calculates the most dominant diurnal and semidiurnal tidal currents using the correction coefficients defined amplitude ratios and phase differences between the major tidal currents on the other hand the fitting method calculates major tidal currents by fitting the amplitudes and phases to a given polynomial function in space without utilization of the correction coefficients validation tests for sampling intervals data truncation effects of low frequency currents and position errors are performed to improve computation results both methods enable us to evaluate effectively and correctly strong tidal currents provided that the signal to noise level in drifter positions is not significantly high the spatial pattern and current ellipses of m2 and k1 tidal currents from drifter positions in the yellow sea are fairly well consistent with those from moored current data application of the two methods to the yellow and east china seas exhibits commonly that m2 and k1 currents rotate clockwise in the east china sea but counterclockwise in the yellow sea interior with rotation direction change around 35 and 34 n respectively

a parametric model for the yellow sea thermal variability a thermal parametric model has been developed for analyzing observed regional sea temperature profiles based on a layered structure of temperature fields mixed layer thermocline and deep layers it contains three major components 1 a first guess parametric model 2 high resolution profiles interpolated from observed profiles and 3 fitting of high resolution profiles to the parametric model the output of this parametric model is a set of major characteristics of each profile sea surface temperature mixed layer depth thermocline depth thermocline temperature gradient and deep layer stratification analyzing nearly 15 000 yellow sea historical 1950 1988 temperature profiles conductivity temperature depth station 4825 expendable bathythermograph 3213 bathythermograph 6965 from the naval oceanographic office s master oceanographic observation data set by this parametric model the yellow sea thermal field reveals dual structure one layer vertically uniform during winter and multilayer mixed layer thermocline sublayer during summer strong seasonal variations were also found in mixed layer depth thermocline depth and thermocline strength

sea level changes an integrated approach sea level changes an integrated approach in october 1985 sepm sponsored a four day conference entitled sea level changes an integrated approach the purpose of the conference was to provide a forum for an interdisciplinary exchange of ideas on sea level changes and to provide an opportunity for integrating various types of evidence in approaching unresolved issues the conference was successful in bringing together scientists from industry academia and government representing all of the major geosciences disciplines presentations of many new papers plus significant releases of data that were previously held proprietary provided fertile ground for discussion this much cited volume represents the best of the material presented at the conference includes the early vail chart

synoptic forcing of the korea strait transport abstract korea strait transport variations in the synoptic frequency band 2 20 days are examined using results of a numerical 3 d primitive equation model satellite observed sea level variations a linear barotropic adjoint dynamic model and observed transports the 3 d numerical model does not assimilate observations and the agreement with the observed transport implies that wind forcing is one of the main contributors to variations in the synoptic band the satellite observed and 3 d model sea level indicate a sea level response to wind stress along the east korean coast that propagates toward the korea strait and changes the sea level slope across the strait the adjoint results indicate that wind stress is most influential in the area east of korea along with secondarily important area along the east china sea shelf break south of japan the mechanism connecting wind stress to transport variations is a kelvin wave propagation that changes sea level slope across the strait leading to the altered geostrophic transport through the strait a strong southerly wind initially produces a sea level set down along the east korea coast and a sea level increase along the shelf break the set down propagates to the korea strait as a kelvin wave sea level across the strait changes and the transport through the strait increases similarly northerly wind stress produces a set up along the korea coast and subsequent decreased transport wind stresses across the yellow and east china seas are not a significant forcing mechanism since kelvin waves would propagate away from the strait barotropic transport response to wind stress is rapid on the order of 3 h but the relatively slow development of the atmospheric forcing on the order of 1 2 days modulates the response

tidal hydrodynamics and fine grained sediment transport on the radial sand ridge system in the southern yellow sea abstract the large radial sand ridge rsr system located in the southern yellow sea off the jiangsu coast is characterized by a radial current field and high suspended sediment concentrations sscs significant rectilinear currents are present over the northern sand ridge area whereas rotary currents prevail over the southern area the transition between the two being dominated by a locally generated trapped wave observations undertaken in 2006 and 2007 indicate a seasonal pattern in the ssc and associated dynamic characteristics the results of a calibrated hydrodynamic model show that the m2 tide dominates the rsr area the maximum tidal amplitude in the core region close to land being approximately 2 m an amphidromic point is located some distance north of the rsr off the abandoned yellow river mouth 121 686 e 34 6 n specifically the eulerian and lagrangian residual currents flow southward in both summer and winter whereas the stokes drift is directed southward in the north and northward in the south moreover in deep water the lagrangian residual current is mainly determined by the eulerian residual current whereas it is strongly influenced by the stokes drift in shallow water the seasonal variation in the residual current in the southern yellow sea is a good indicator for the location of the yellow sea warm current yswc in both summer and winter measurements show that a ssc peak appears off the abandoned yellow river delta in response to the strong currents and plentiful supply of fine grained sediment from coastal erosion another ssc peak lying close to the north branch of the changjiang river mouth is related to the abundant suspended sediment supplied by the river seasonal variations in ssc are observed in the study area maximum average values and widest diffusion from land occurring in winter this being contrasted by minimum mean values in summer sensitivity experiments demonstrate that the main factor influencing the distribution of ssc is the tide while river discharge wind and wave effects are small and very localized to explain the seasonal variation in ssc the role of hydrodynamics initial conditions and temperature are tested in the model the results show that the hydrodynamics play a significant role whereas the initial conditions only have a minor regional influence temperature on the other hand is also shown to greatly influence the seasonal variation in ssc because of substantial changes in the viscosity of the water and the erosion shear stress the modeled results are used to calculate sediment fluxes which are shown to be consistent with the lagrangian residual current pattern while wind waves can significantly change the fluxes in winter bed elevations change substantially on a monthly time scale in general the deep channels are undergoing erosion while the shallow ridges and coastal tidal flats are accreting the net sediment transport being directed towards the coastal tidal flat and the changjiang yangtze river subaqueous delta

geochemical and climatic effects of increased marine organic carbon burial at the cenomanian turonian boundary perhaps the most significant event in the cretaceous record of the carbon isotope composition of carbonate1 2 other than the 1 2 5 negative shift in the carbon isotope composition of calcareous plankton at the cretaceous tertiary boundary3 is the rapid global positive excursion of 2 13c enrichment which took place between 91 5 myr and 90 3 myr late cenomanian to earliest turonian c t boundary event 1 4 5 this excursion has been attributed to a change in the isotope composition of the marine total dissolved carbon tdc reservoir resulting from an increase in rate of burial of 13c depleted organic carbon which coincided with a major global rise in sea level5 during the so called c t oceanic anoxic event oae 6 here we present new data from nine localities which demonstrate that a positive excursion in the carbon isotope composition of organic carbon at or near the c t boundary7 8 is nearly synchronous with that for carbonate and is widespread throughout the tethys and atlantic basins fig 1 as well as in more high latitude epicontinental seas the postulated increase in the rate of burial of organic carbon may have had a significant effect on co2 and o2 concentrations in the oceans and atmosphere and consequent effects on global climate and sedimentary facies

numerical investigation of the generation of continental shelf waves and their role in the westward shift of the yellow sea warm current abstract the yellow sea warm current yswc which carries warm saline water into the yellow sea ys exhibits a typical northward upwind flow during winter observations have shown that the path of the yswc has shifted to the west from the deep trough and it has been suggested that continental shelf waves csws may play an important role in this westward shift however the source of southward propagating csws that drive the westward shift of the yswc remains unclear the objective of this study is to reveal the generative mechanism of csws and their role in driving the westward shift of the yswc numerical models with an idealised topography show that the westward shift of the northward flow propagates southward along the western slope offshore of china with a typical speed of 2 99 m s 1 comparable to the theoretical phase speed of a first mode csw csws driving the westward shift are generated on the northern slope primarily by the scattering of kelvin waves that develop due to northerly winds and propagate northward into the ys along the eastern boundary of the korean peninsula model experiments with a realistic topography consistently support the idea that kelvin wave scattering is a primary source of the southward propagation of the csws that drive the westward shift of the yswc

foraminiferal evidence for cenomanian sequence stratigraphy and palaeoceanography of the boulonnais paris basin northern france abstract a middle to upper cenomanian chalk succession in the northwestern european paris basin escalles section was investigated with respect to its sediment composition biofacies and foraminiferal content most planktic foraminifers exhibit a high frequency cyclicity in their distribution pattern and show little relationship to the sequence stratigraphic subdivision a few characteristic species of benthic foraminifers tritaxia pyramidata ataxophragmium compactum dorothia levis and gavelinella cenomana are related in their frequency distribution to certain systems tracts other benthic foraminiferal species are more evenly distributed through the systems tracts cluster analysis and factor analysis allow the separation of three benthic foraminiferal biofacies domains which exhibit a characteristic frequency distribution pattern with respect to sequence stratigraphy biofacies 1 is dominant in the highstand systems tract hst and biofacies 3 is characteristic for the transgressive systems tract tst biofacies 2 is most abundant around the maximum flooding downlap surface mfs and less abundant around the sequence boundary factor analysis shows that most of the variance in the data set is explained by variables related to plankton productivity variables related to changes in water depth and changes in sea level have minor influence on the variance of the whole data set but have some influence on the variance of the benthic foraminiferal data set the different reaction of benthic and planktic foraminifers to relative sea level changes is also recorded in the total number of foraminifers per gram sediment foraminiferal number and in the ratio between planktic and benthic foraminifers p b ratio the foraminiferal number is highest at the mfs and lowest at the sequence boundaries of the investigated depositional sequences the p b ratio has no correlation with the sequence stratigraphic subdivision but shows a high frequency cyclicity the abundance pattern of planktic foraminifers is controlled by changes in the productivity of calcareous plankton the regular variation in calcareous plankton productivity leads to marl low productivity chalk high productivity cycles that form conspicuous couplets in the section the productivity cycles are also recorded in gamma ray logs in the environmental setting of the escalles section in contrast the abundance patterns of benthic foraminifers are more influenced by relative sea level changes changes in water depth and variations in substrate composition the stacking of probably precession controlled development of couplets lead to a distinct 100 000 year cyclicity that does not match very well with published sequence stratigraphic subdivisions

modeling temperature inversion in southeastern yellow sea during winter 2016 a significant temperature inversion with temperature differences larger than 3 c was observed in the southeastern yellow sea ys during february 2016 by analyzing in situ hydrographic profiles and results from a regional ocean model for the ys this study examines the spatiotemporal evolution of the temperature inversion and its connection with wind induced currents in winter observations reveal that in winter when the northwesterly wind prevails over the ys the temperature inversion occurs largely at the frontal zone southwest of korea where warm saline water of a kuroshio origin meets cold fresh coastal water our model successfully captures the temperature inversion observed in the winter of 2016 and suggests a close relation between northwesterly wind bursts and the occurrence of the large inversion in this respect the strong northwesterly wind drove cold coastal water southward in the upper layer via ekman transport which pushed the water mass southward and increased the sea level slope in the frontal zone in southeastern ys the intensified sea level slope propagated northward away from the frontal zone as a shelf wave causing a northward upwind flow response along the ys trough in the lower layer thereby resulting in the large temperature inversion diagnostic analysis of the momentum balance shows that the westward pressure gradient which developed with shelf wave propagation along the ys trough was balanced with the coriolis force in accordance with the northward upwind current in and around the inversion area

seasonal circulation patterns of the yellow and east china seas derived from satellite tracked drifter trajectories and hydrographic observations abstract we investigated seasonal circulation patterns of the yellow and east china seas yecs by reviewing previous works on the circulation and its dominant currents and taking into account newly compiled trajectories of satellite tracked drifters collected between the 1980s and 2000s the circulation patterns suggested before the 1990s can be categorized into two groups depending on the identified origin of the tsushima warm current in the korea tsushima straits i branching from the kuroshio southwest of kyushu or ii northeastward continuation of the taiwan strait throughflow the branching of the kuroshio southwest of kyushu and northeast of taiwan was clearly evidenced by current measurements and concurrent hydrographic surveys however there is still no clear evidence for the northeastward pathway of taiwan strait throughflow across the mid shelf area of the east china sea target oriented surveys in the 1990s and 2000s employing advanced instruments such as drifter tracking and acoustic doppler current profiler measurements now provide decisive proof of the clockwise rounding of the cheju warm current around jeju do throughout the year of the northeastward extension of changjiang discharge in summer and of the presence of the yellow sea warm current only in winter thus both coastal currents in shallow water and secondary branch currents of the kuroshio such as the yellow sea warm current are found to significantly change from winter to summer to better present the basic pattern of yecs circulation and its seasonality we have constructed seasonal circulations patterns based on review results on the newly compiled drifter trajectories and on hydrographic observations further investigations should be carried out in future with support of comprehensive current measurements on shelf areas and through elaborate numerical modeling

a simulation of mid cretaceous climate a series of general circulation model experiments utilizing genesis have been completed for the mid cretaceous based on geography variable atmospheric carbon dioxide concentrations 2 to 6 times present day concentrations and variable poleward oceanic heat flux 6 to 1 2 1015 w increased from present day by combining all three major variables co2 geography and oceanic heat flux the distribution of mid cretaceous temperatures can be achieved in the simulations increased co2 is required to promote global warmth and increased oceanic heat flux is required to prevent the tropics from overheating with higher levels of co2 four times present day co2 with 1 2 1015 w provided the best match to the distribution of mid cretaceous data the best match to the cretaceous observations was achieved with a globally averaged surface temperature increase of 6 2 c at the lower end of past estimates of mid cretaceous warmth this value may be a better estimate of mid cretaceous global warming finally the model experiments can be used to provide a paleocalibration of the global warming expected for a doubling of atmospheric carbon dioxide the best estimates for the mid cretaceous appear to be a 2 5 to 4 0 c sensitivity in the mid to upper range of the sensitivity of current climate models used to assess future global change

an asymmetric upwind flow yellow sea warm current 1 new observations in the western yellow sea 1 the winter water mass along the yellow sea trough yst especially on the western side of the trough is considerably warmer and saltier than the ambient shelf water mass this observed tongue shape hydrographic feature implies the existence of a winter along trough and onshore current often referred to as the yellow sea warm current yswc however the yswc has not been confirmed by direct current measurements and therefore skepticism remains regarding its existence some studies suggest that the presence of the warm water could be due to frontal instability eddies or synoptic scale wind bursts it is noted that in situ observations used in most previous studies were from the central and eastern sides of the yst even though it is known that the warm water core is more pronounced along the western side data from the western side have been scarce here we present a set of newly available chinese observations including some from a coordinated effort involving three chinese vessels in the western yst during the 2006 2007 winter the data show unambiguously the existence of the warm current on the western side of yst both the current and hydrography observations indicate a dominant barotropic structure of yswc the westward deviation of yswc axis is particularly obvious to the south of 35 n and is clearly associated with an onshore movement of warm water to the north of 35 n the yswc flows along the bathymetry with slightly downslope movement we conclude that the barotropic current is mainly responsible for the warm water intrusion while the ekman and baroclinic currents play an important but secondary role these observations help fill an observational gap and establish a more complete view of the yswc

comparison of wind and tidal contributions to seasonal circulation of the yellow sea 1 seasonal circulation of the yellow sea ys in response to wind and tidal forces is examined using a three dimensional numerical model wind forcing affects the wintertime circulation of the ys on the other hand the summer southerly monsoon is weak and therefore has little impact on the circulation on the basis of comparative experiments with and without wind conditions results indicate that the yellow sea warm current yswc along the ys trough exists regardless of wind forcing however strong winter northerly winds intensify the southward coastal flows along both coasts of the ys and therefore the northward intrusion of the yswc becomes stronger these flows in the ys are substantially weakened when wind forcing is not applied to the model in addition to wind driven circulation tide induced circulation is also dominant in the ys particularly in summer in winter the tidal effect weakens the upwind and downwind flows in response to the strong northerly winds while in summer tidal forcing induces a strong southward residual flow along the western slope and a cyclonic gyre with a bottom cold water dome at the central region of the ys the southward residual current possibly explains the southward movement of the yellow sea bottom cold water as observed in summer comparison to the effects of parameterized tidal mixing suggests that residual flow driven by explicit tidal forcing plays an important role in the summertime circulation of the ys

the cenomanian turonian oceanic anoxic event ii palaeoceanographic controls on organic matter production and preservation correlation of the 13c spike with the well dated occurrences of strata rich in organic carbon detailed in schlanger et al this volume indicates that a global episode of intense organic carbon orgc burial took place during the latest cenomanian earliest turonian oceanic anoxic event oae a plenus through i labiatus macrofossil zones and upper r cushmani trz through w archecretacea prz foraminiferal zones over a period of no more than 1 million years m y the shape of the 13c curve indicates that rates of orgc burial gradually increased in the early part of the late cenomanian increased more rapidly in the later cenomanian and levelled off at peak values in latest cenomanian early turonian time during the maximum rate of orgc burial the 13c values decreased nearly to pre late cenomanian levels in the early to middle turonian the decrease in 13c reflects decreasing rates of orgc burial following the cenomanian turonian oceanic anoxic event as well as the probable oxidation and return of significant amounts of orgc to the oceans following regression and re oxygenation of much of the deeper water masses in contact with the seafloor

frontal circulation and westward transversal current at the yellow sea entrance in winter 1 during the wintertime monsoon a tongue shaped thermohaline front is established at the yellow sea ys entrance where the cheju warm current cwc water originating in the kuroshio and the ys cold water meet the frontal circulation as well as the frontal structure has been investigated by analyzing comprehensive conductivity temperature density data float tracks current data and wind data the front develops by the westward advance of the cwc water but it is bounded by the shallow changjiang banks cb that acts like a stopper in the deep part of the ys entrance the northern part of the tongue shaped front displays a wave like motion of 20 km in amplitude and 80 km in wavelength and isotherms isohalines and isopycnals are declined downward toward the north the geostrophic current field indicates formation of a cyclonic circulation along the front which consists of a westward transversal current tc along 34 n and a southeastward outflow along the 50 m isobath of the cb the westward trajectories of floats along the northern front support existence of the tc and a superposition of float tracks evidences cyclonic frontal circulation the new observational findings of the tc and the cyclonic circulation do not match the classical paradigm of a northerly wind driven circulation which consists of the northward inflow through the central trough and the southward outflow on the coastal sides the cyclonic turning of the cold water around the warm tongue stands in contrast with the anticyclonic rounding of the warm cwc water around jeju do

episodic surface intrusions in the yellow sea during relaxation of northerly winds the surface currents over the yellow and east china seas are mapped from the geostationary ocean color imager goci based on a composite of six intrusion events in january april the strong northward surface current in the yellow sea is shown to be concentrated along the deep trough accompanied by a broad northward surface current over the east china sea from the corresponding surface winds the episodic northward surface flow bursts appear to be associated with abrupt changes from the strong northerly winds to weak southerly winds during cold front passages a three dimensional model driven with observed surface winds is used to simulate the observed shelf wide response to northerly winds there is an outstanding agreement between the simulated and observed surface currents the surface intrusion in the yellow sea is shown to be driven primarily by a barotropic longitudinal surface slope while the strong northward current in the east china sea is associated with a coastal trapped wave moreover the surface intrusion is associated with a large volume transport suggesting that the transient intrusions could be important in the northward heat transport the unprecedented capability of goci satellite in providing a regional circulation pattern in conjunction with complementary model simulations could contribute greatly to understanding of the dynamics of the yellow and east china seas

milankovitch control of foraminiferal assemblages from the cenomanian of southern england a succession of foraminiferal assemblages recorded across three cenomanian marl chalk marl rhythms is interpreted as a function of occasional high pelagic carbonate production induced by warmer surface waters the changes in the benthonic assemblages are related to the introduction of increased amounts of carbonate sediment fluctuations in surface water temperature and associated productivity changes may be a consequence of orbital precessional forcing of the climate chalk formation is likely to have been much more rapid than marl formation

inertial oscillations in the korea strait inertial oscillations io are examined in the korea strait based on measurements from 13 acoustic doppler current profilers covering the time period may 1999 through march 2000 strong io responses to wind stress occur during summer a simple linear model predicts that winter wind stress is expected to generate inertial responses of the same order of magnitude as those in summer however the observed winter io response is much weaker than predicted during summer the currents within the mixed layer and below the mixed layer are of comparable amplitude but in opposite directions the depth at which the currents reverse directions varies throughout the year as the mixed layer deepens from about 40 m during summer to the bottom of the water column in november during winter the velocity structure is more uniform in depth with currents in the same direction throughout the water column one possible explanation for these phenomena is related to the combined effect of the strait boundaries and the strong summer stratification the stratification prevents the wind stress momentum flux from mixing downward below the thermocline and thus allows the development of a bottom current separate from the surface current such a velocity structure is necessary to satisfy the no flow condition through the land boundaries

evolution of wind driven flows in the yellow sea during winter to examine the evolution of the wind driven flows in the yellow sea ys during winter ocean circulation was simulated using a three dimensional ocean model with realistic topography and atmospheric forcing the simulated sea surface temperature ocean currents and path of the yellow sea warm current yswc agreed with observations southward currents along the korean coast and the chinese coast in winter were also effectively identified spectra of the daily mean winds and the yswc velocities in the subsurface layer had dominant peaks at 12 and 20 day periods time lagged correlation analysis suggested that the downwind flow in the surface layer reacts concurrently to the northwesterly wind in winter whereas the subsurface layer responds with a delay one day after the wind burst an upwind current in the subsurface layer appeared in the center of the trough whereas the downwind flow in the surface layer decreased significantly two days later the upwind flow in the subsurface layer shifted to the west of the trough while the downwind flow along the korean coast strengthened these flow responses to the wind variations resulted in a clockwise circulation in the ys during winter

yellow and east china seas response to winds and currents the influences of the kuroshio current kuc taiwan warm current twc and surface wind stress on the yellow and east china seas yes are examined using tracers in a princeton ocean model two experiments are performed one with wind stress and one without seasonal variations in the inflow and outflow of the twc and tsushima current are specified to examine the effects of the current transports two separate tracers are inserted into each model experiment to track the pattern of kuc and twc waters into the yes the two main areas of kuc and twc water movement into the yellow sea are the southern entrance to the yellow sea trough and the yangtze relict river valley results indicate that kuc and twc waters advect into the yellow sea regardless of wind stress however in the yellow sea during winter the wind stress increases kuc and twc concentration at 20 m the wind stress also produces short time period events that horizontally advect water masses and spatially smooth seasonally averaged water mass concentrations the bottom ekman layer appears to be one of the mechanisms driving the northward bottom flow across the east china sea shelf the bottom friction layer is stronger in summer when the twc velocity is high the bottom friction layer draws kuc water across the bottom of the continental shelf into the yangtze relict river valley and generates upwelling along the chinese coast

sequence stratigraphy and biological signals statistical studies of benthic foraminifera from liassic series abstract a study of benthic foraminifera from the toarcian in quercy aquitaine basin france shows that micropaleontological assemblages are influenced by sea level changes the percentages of coiled and straight nodosarridae lenticulina citharina differ during periods of low sea level to high sea level statistical analysis of all the taxa in the successive levels of a section multiple factorial analysis of correspondences methods of automatic clustering show that there is a perfect distribution of the samples into groups corresponding to the type of systems tract differences within the foraminiferal benthic biocoenosis allow the successive systems tracts to be separated the first axis in the multiple analysis of correspondences coincides with a gradient of biotic capacity and seems to be connected with the sea level changes the second axis could be linked with depth the renewal rate of taxa and the factorial diversity of the sampling levels show fluctuations associated with 4th 3rd and 2nd order variations of the sea level these connections are caused by intricate processes with ecological biogeographical and bioevolutionary influence however the micropaleontological assemblages can be good indicators of systems tracts and unconformities this is particularly important within deposits that have homogeneous lithology

does the yellow sea warm current really exist as a persistent mean flow does saline water of kuroshio origin intrude into the yellow sea interior by a persistent mean current through the yellow sea warm current or by an intermittently generated wind driven current this very fundamental question is discussed by analyzing comprehensive conductivity temperature depth data collected over the entire southern yellow sea basin and by analyzing satellite tracked drifter trajectories collected in 1996 and 1997 in the southwestern yellow sea relatively saline water 33 0 34 0 psu persists year round implying a northwestward intrusion of cheju warm current water cwcw this water is a mixture of saline cwcw with salinity higher than 34 0 psu and fresh yellow sea waters with salinity 33 0 psu during the winter monsoon the mixed water distribution is tongue shaped apparently intruding from the cwcw area at the same time a strong thermohaline front with a horizontal form similar to the greek letter forms across the southern entrance of the central yellow sea trough and separates the mixed water area from the cwcw during the summer monsoon the cwcw intrusion is weak and the mixed water that intruded in the previous winter monsoon remains inside the trough as its salinity decreases in winter occasional collapses of part of the front on the western side of the trough are observed presumably in response to an imbalance between northwest currents generated by strong northerly wind bursts and southeast tide induced residual currents saline water in the frontal zone may then flush into the southwestern yellow sea through the collapsed area of the front we conclude that the yswc is not a persistent mean current we also conclude that cwcw may be transported to the southwestern yellow sea in winter by the intermittently generated northwest currents on the western slope of the trough which override the tide induced residual currents that flow to the southeast in this part of the basin

low productivity and slow deep water circulation in mid cretaceous oceans paleofertility estimates are derived from organic carbon accumulation rates determined in nonbioturbated mid cretaceous deep sea deposits using organic carbon preservation factors observed in laminated sediments from anoxic holocene environments the estimated mid cretaceous primary production rates are as much as an order of magnitude lower than those measured in today s oceans an evaluation of dissolved oxygen budgets using a simple oceanic circulation model indicates very low deep water renewal rates in mid cretaceous oceans 28 references 2 tables 4 figures

the depth dependency of planktonic benthic foraminiferal ratios constraints and applications abstract study of the ratio between planktonic and benthic foraminifera in a great number of areas shows that variation of this ratio with depth can be described using organic matter flux equations essentially the share of benthic foraminifera in the total association is inversely proportional to depth as is the amount of organic matter resulting from primary productivity reaching the sea bottom variation in the p b ratio from area to area appears to be strongly dependent on the amount of inbenthic living foraminifera if the ratios are corrected for this the regressions between the proportion of planktonic foraminifera p and depth appear to be near identical in the gulf of mexico the gulf of california the west coast of the usa and the adriatic sea this regression can be described by depth e 3 58718 0 03534 p a study of the behaviour of this function in nine cores from the adriatic upper quaternary reveals that the palaeodepth reconstructions are not influenced by fluctuations in productivity and temperature but that they are significantly influenced by redeposition of fine grained deposits

a role of the yellow and east china seas in the development of extratropical cyclones in winter abstractto investigate whether the relatively warm yellow and east china seas play an active role in the deepening of extratropical cyclones over east asia during winter surface wind vectors downloaded from the quick scatterometer quikscat website are used to compute the standard deviation of surface vorticity at resolution in addition a regional numerical atmospheric model is adopted to find atmospheric and or oceanic conditions favorable for development of extratropical cyclones over the study area these satellite derived and modeled vorticity fields demonstrate that on average extratropical cyclone activity is moderate over the warm yellow and east china seas this is because enhanced lower level baroclinicity over these ocean areas is transferred as far as the shelf break of the east china sea by strong northwesterly surface winds based on the numerical model results the weak northwesterly surface wind condition is required for enhancing lower level baroclinicity over the yellow and east

sequence stratigraphy in the upper cretaceous of the basco cantabrian basin northern spain the sedimentary cycles of the cenomanian to maastrichtian were investigated in the basco cantabrian basin bcb in northern spain provinces of alava vizcaya and burgos the depositional area was a distally steepened carbonate ramp which extended from catalonia northwestwards to the basque country the investigated sediments range from calciturbidites and pelagic marls to marl limestone alternations deposited on a distal carbonate ramp shallow marine limestones marls and intertidal clastics and carbonates were deposited on the proximal part of the carbonate ramp the establishment of a regional sequence analysis is based on the investigation of seismic profiles well logs and outcrop sections examples of outcrop sections are interpreted in terms of sequence stratigraphy unconformities of third and second order cycles depositional geometries systems tracts the sequence stratigraphic interpretation of outcrop sections is based on facies analysis interpretation of observed depositional geometries and correlation of unconformities and marine flooding surfaces through the basin a biostratigraphic framework is established based on ammonites inoceramids planktonic and benthic foraminifera as a result a regional sequence stratigraphic cycle chart is presented and compared with published global cycle charts the correlation of the regional cycle chart with published cycle charts is good in the cenomanian and turonian several sequence boundaries in the bcb are shifted by up to one biozone compared with the global chart some type 1 boundaries of the standard chart are only type 2 in the bcb important type 1 boundaries in the bcb are top geslinianum zone with a 100 m lowstand wedge at the basis of the sequence sequence boundary 92 2 base petrocoriense zone with a 250 m shallowing upwards lowstand wedge at the basis sequence boundary 89 2 and within the syrtale zone sequence boundary 85 0

the cenomanian turonian oceanic anoxic event i stratigraphy and distribution of organic carbon rich beds and the marine δ13c excursion marine strata deposited during late cenomanian and early turonian time display lithological faunal and geochemical characteristics which indicate that significant parts of the world ocean were periodically oxygen deficient at or very close to the cenomanian turonian boundary between 90 5 and 91 5ma ago oxygen deficiencies were particularly marked over a period of 1ma this short lived episode of oceanic oxygen deficiency has been termed the cenomanian turonian oceanic anoxic event oae the widespread distribution of anoxic sediments deposited synchronously during such a short lived event indicates that such sediments are not simply the product of coincidental local climatic or basinal water mass characteristics but are the result of a global expansion and intensification of the cenomanian turonian oxygen minimum zone related to feedback between sea level rise and regional palaeoceanography the palaeoceanography of the cenomanian turonian oae is discussed in detail in a companion paper by arthur et al 1987 from authors

orbitally mediated cycles from the turonian of southern england their potential for high resolution stratigraphic correlation detailed sampling of two sections of turonian aged chalk from southeast england for foraminifera has revealed that cyclical abundance changes in many species and genera were mediated by orbitally induced climatic cycles these cycles can be used for high resolution stratigraphic correlation of the two sections and as a possible means of re estimating the duration of the turonian period

current and tide observations in the southern yellow sea determination of mean currents and tides are particularly difficult in coastal regions flows are often nongeostrophic and short lived bathymetry is frequently not adequately known and can greatly influence coastal dynamics to better quantify tides and currents in the southern yellow sea three pressure gauges and three acoustic doppler current profilers adcps were bottom moored for 4 6 month intervals at depths ranging from 77 to 89 m tidal range is over 2 m and maximum current velocities are between 50 and 80 cm s at the mooring locations the present data are analyzed for 13 significant tidal constituents which are found to account for 85 of the sea surface height variability m2 is the dominant constituent followed by s2 and k1 flow is dominated by the tides mean currents are relatively small ranging from 1 5 cm s at the northern mooring to 4 cm s at the southern mooring delineations of barotropic and depth dependent currents are made from the adcp measurements in terms of mean and eddy kinetic energy currents are found to be most depth dependent in the near surface layers approximately 85 90 of the eddy kinetic energy is depth independent

holocene paleoenvironmental changes in mud area southwest off cheju island east china sea evidence from benthic foraminiferal assemblages and stable isotope records abstract a sediment core retrieved from the mud area southwest off cheju island masci was analysed for benthic foraminifera grain size and stable isotopes and constrained by ams14c dating holocene paleoenvironmental changes in this broad shallow shelf were investigated with special focus on the evolution of the masci and its related ocean eddy system the results indicate that the east china sea shelf has undergone four major environmental evolution stages during the holocene prior to 9 8 cal kyr bp the benthic foraminiferal assemblages were dominated by low salinity shallow water species ammonia beccarii linnaeus elphidium advenum cushman and cribrononion subincertum asano reflecting a near coast deposit environment a noticeable transition of the benthic foraminifera from an a beccarii dominated to ammonia compressiuscula brady dominated assemblage taking place at approximately 9 8 cal kyr bp together with a contemporaneous increase in 18o and 13c provides evidence that a rapid rise in sea level occurred at this time in the east china shelf a gradual increase in 18o between 9 8 and 6 cal kyr bp indicates a steady strengthening influence of open ocean water on the area under study a sudden increase in the abundance of benthic foraminifera along with a decrease in the coarse fraction imply that an early eddy circulation system was established since almost 6 cal kyr bp in the masci this eddy circulation system was quite weak but gradually strengthened between 6 and 3 cal kyr bp possibly due to the intrusion of the yellow sea warm current yswc a more stable mud deposition period characterised by a high sedimentation rate of fine grained sediment and lighter value of 13c starting at approximately 3 cal kyr bp indicates that the masci was formed mainly during the late holocene we believe that the strengthened yswc since 3 cal kyr bp might increase the trap efficiency of the eddy system thereby accounting for the high sedimentation rate of mud deposits during this period

tongue shaped frontal structure and warm water intrusion in the southern yellow sea in winter 1 in winter a thermohaline front forms at the yellow sea ys entrance where the warm and saline cheju warm current cwc water meets cold coastal water the frontal structure as well as the northwestward intrusion of the warm water was investigated by analyzing conductivity temperature depth ctd data tracks of drifting floats moored current data and satellite images the cwc water advances westward as a tongue with its tip heading westward across the ys entrance not intruding northward along the deepest part of the ys trough whereas a secondary warm water band is developed northwestward along the western flank of the trough floats in the warm tongue moved northwestward across the western frontal zone where the frontal structure was weak reflecting the northwestward intrusion along the 50 70 m isobaths through the frontal zone currents in the trough do not always meet the upwind flow theory that in an elongated basin the wind driven flow is upwind in the deep channel but rather show the predominance of the southward downwind flow model experiments show that on the western flank of the trough both the southeastward tide induced residual flow and the southeastward flow due to the nonlinear effect between tide and wind are generated at the same time thus the intermittent intrusion of the cwc across the western frontal zone may be closely associated with the predominance of the upwind flow over the southeastward nonlinear interacted flow

effects of the yellow sea warm current on the winter temperature distribution in a numerical model 1 the temperature distribution and circulation patterns in the yellow sea ys are examined by using a wave tide circulation coupled numerical model this model sufficiently reproduces the variation of the warm tongue structure of the yellow sea warm current yswc from the double branches flowing along the ys trough and the western 60 m isobath in january to the single stream along the western temperature front in march this is observed in both the long term monthly climatology and the satellite based sea surface temperature images in recent years examining the local heat balance in the numerical model during the entire cooling period it is found that the yswc has a very important influence on the ys warm tongue structure compared with the surface cooling the influence of the advection is small in the coastal shallow area but large in the deep warm tongue area up to 50 of the magnitude of heat flux although bathymetry is the essential factor which causes the temperature front the yswc is the key factor which positions shapes and maintains the warm tongue structure this helps to affirm the existence of the yswc at least as a monthly mean flow however more high resolution current observations in deeper layers west of cheju island and the western fork of the ys trough are needed to confirm the existence of the yswc and its characteristic timescale in the real ys

sea level variations in relation to coastal flow around the gulf of alaska adjusted sea level deviations at six tide stations around the gulf of alaska were examined in light of our recent knowledge of the flow regime on the east side of the gulf a maximum in the deviations seems to be caused by winter barotropic flow on the shelf on the north side of the gulf the maximum in fall is apparently produced by a marked increase in flow of the baroclinic coastal current farther west the seasonal sea level signal is appreciably reduced

changes in paleoenvironments in the atlantic ocean during cretaceous times results from black shales studies large parts of the cretaceous atlantic ocean are characterized by the wide spread deposition of organic carbon rich sediments black shales with a maximum occurrence during aptian albian and cenomanian turonian times in order to explain the origin of these black shales changes in the amount and type of organic matter in relation to changes in paleogeography paleoceanic circulation and paleoclimate have been investigated in detail the study is mainly based on calculation of accumulation rates of marine and terrigenous organic carbon organic carbon sedimentation rate relationships and estimates of paleoproductivity