the age of yellow river water in the bohai sea 1 to quantitatively understand the transport timescales of dissolved material discharged from large rivers into a semienclosed sea the age of yellow river water in the bohai sea was calculated with the constituent oriented age and residence time theory cart and particle tracking method yellow river water has a mean age of 3 0 years for the entire bohai sea the spatial variation of the water age is significant 1 2 years near the yellow river estuary but 3 9 years in the liaodong bay however the temporal variation in water age is insignificant the water particles released at the river mouth need only several days to reach the estuary area the great water age 1 2 years near the yellow river estuary is caused by the presence of old water particles that initially left this area but returned to this area again without the reentry of yellow river water from the yellow sea to the bohai sea the mean age of yellow river water in the entire bohai sea decreases to 1 2 years calculations without tidal forcing give a reduction in water age by more than 50 suggesting that tidal forcing plays the most dominant role in controlling the age of yellow river water in the bohai sea calculations without winds give an increase in water age by 20 30 suggesting that wind forcing is secondary factor to the age of yellow river water changes in discharge of the yellow river and in thermal stratification have limited influence on the age of yellow river water

submarine groundwater discharge sgd into the yellow sea revealed by 228ra and 226ra isotopes implications for global silicate fluxes abstract we estimated the magnitude of submarine groundwater discharge sgd into the yellow sea which is one of the largest continental shelves in the world using 226 ra and 228 ra isotopes on the basis of 228 ra and 226 ra mass balance models we estimated the advective flux of 226 ra through sgd to be 270 10 12 dpm yr 1 in the yellow sea using this 226 ra flux and the measured 226 ra activity in coastal groundwater the submarine discharge of groundwater mostly brackish groundwater was calculated to be at least 40 of the river water input 2 3 10 11 m 3 yr 1 then on the basis of the sgd and the concentration of si in coastal groundwater we estimated the flux of si through sgd to be 20 100 of that associated with river discharge 23 10 9 mol yr 1 this large sgd is likely to be due to the high tidal range up to 10 m and the wide distribution of sandy sediments in the yellow sea favorable for the recirculation of seawater through bottom sediments and rocks this result from such a large area implies that the si flux through sgd may be significant on a global scale

iron isotope constraints on fe cycling and mass balance in oxygenated earth oceans the fe isotope composition of proterozoic to modern clastic sedimentary rocks and aerosols defines a range ind 56 fe values that is only slightly more variable than the range of fe isotope com positions measured in terrestrial igneous rocks indicating that chemical weathering sedimentary transport and diagenesis play only a minor role in producing fe isotope variations in environ ments where fe redox conditions have been controlled by current levels of atmospheric oxygen in contrast the fe isotope composi tions of hot fluids 300 8c from mid ocean ridge mor spread ing centers define a narrow range that is shifted to lower d 56 fe values by 0 2 0 5 as compared to igneous rocks these new data allow a conceptual model for the fe isotope composition of the oxic oceans that predicts large ranges in fe isotope composition under conditions of changing aerosol and mor fe fluxes such as during periods of major worldwide glaciation

the effects of tides on the water mass mixing and sea ice in the arctic ocean in this study we use a novel pan arctic sea ice ocean coupled model to examine the effects of tides on sea ice and the mixing of water masses two 30 year simulations were performed one with explicitly resolved tides and the other without any tidal dynamics we find that the tides are responsible for a 15 reduction in the volume of sea ice during the last decade and a redistribution of salinity with surface salinity in the case with tides being on average 1 0 1 8 practical salinity units psu higher than without tides the ice volume trend in the two simulations also differs 2 09 103 km3 decade without tides and 2 49 103 km3 decade with tides the latter being closer to the trend of 2 58 103 km3 decade in the piomas model which assimilates sst and ice concentration the three following mechanisms of tidal interaction appear to be significant a strong shear stresses generated by the baroclinic clockwise rotating component of tidal currents in the interior waters b thicker subsurface ice ocean and bottom boundary layers and c intensification of quasi steady vertical motions of isopycnals by 50 through enhanced bottom ekman pumping and stretching of relative vorticity over rough bottom topography the combination of these effects leads to entrainment of warm atlantic waters into the colder and fresher surface waters supporting the melting of the overlying ice

westward shift of the yellow sea warm salty tongue 1 the accumulated in situ hydrographic survey as well as the satellite observed sea surface temperature sst show consistent westward shifting of the yellow sea warm salty tongue yswst in winter a 2 d thermal model is used to show the westward shifting of the yswst due to cooling and advection the mitgcm is applied to simulate the circulation in the yellow and east china seas under the northern monsoon wind in winter the sea surface height ssh is adjusted to have a ridge in the channel and a trough in the 50 70 m iso bath in the yellow sea the barotropic transport of ssh and baroclinic transport of horizontal density gradient play the major role for the shifting of the yswst while the ekman wind drift plays a minor role

influence of sea level rise on iron diagenesis in an east florida subterranean estuary abstract subterranean estuary occupies the transition zone between hypoxic fresh groundwater and oxic seawater and between terrestrial and marine sediment deposits consequently we hypothesize in a subterranean estuary biogeochemical reactions of fe respond to submarine groundwater discharge sgd and sea level rise porewater and sediment samples were collected across a 30 m wide freshwater discharge zone of the indian river lagoon florida usa subterranean estuary and at a site 250 m offshore porewater fe concentrations range from 0 5 m at the shoreline and 250 m offshore to about 286 m at the freshwater saltwater boundary sediment sulfur and porewater sulfide maxima occur in near surface oc rich black sediments of marine origin and dissolved fe maxima occur in underlying oc poor orange sediments of terrestrial origin freshwater sgd flow rates decrease offshore from around 1 to 0 1 cm day while bioirrigation exchange deepens with distance from about 10 cm at the shoreline to about 40 cm at the freshwater saltwater boundary doc concentrations increase from around 75 m at the shoreline to as much as 700 m at the freshwater saltwater boundary as a result of labile marine carbon inputs from marine sgd this labile doc reduces fe oxides which in conjunction with slow discharge of sgd at the boundary allows dissolved fe to accumulate upward advection of fresh sgd carries dissolved fe from the fe oxide reduction zone to the sulfate reduction zone where dissolved fe precipitates as fe sulfides saturation models of fe sulfides indicate some fractions of these fe sulfides get dissolved near the sediment water interface where bioirrigation exchanges oxic surface water the estimated dissolved fe flux is approximately 0 84 m fe day per meter of shoreline to lagoon surface waters accelerated sea level rise predictions are thus likely to increase the fe flux to surface waters and local primary productivity particularly along coastlines where groundwater discharges through sediments

iron isotope fractionation in a sulfide bearing subterranean estuary and its potential influence on oceanic fe isotope flux we trace pathways of fe reactions in the indian river lagoon florida usa subterranean estuary using fe isotopes to provide new constraints on fe isotopic fractionation in a sulfide bearing subterranean estuary porewater 56fe values increase from 1 16 at 115cm depth to 0 2 at 7cm depth due to isotope fractionation in three distinct lithostratigraphic zones the deepest zone contains orange sands with elevated fe oxide contents 0 2wt that dissolve through diagenetic fe oxide reduction and elevate fe concentrations in porewaters 100 to 300 m l this reaction causes porewater 56fe values to be 1 lighter than the sediment 56fe values an intermediate zone contains white fe poor sands with fe oxide contents 0 1wt and dissolved fe concentrations 20 m l this zone is a sink for dissolved fe through adsorption of isotopically heavy dissolved fe ii onto mineral surfaces this adsorption results in porewater 56fe values that are as much as 1 8 lighter than sediment 56fe values the uppermost zone contains organic carbon and fe sulfide rich black sediments with low dissolved fe 1 m l and elevated porewater sulfide up to 600 m l concentrations precipitation of isotopically light fe sulfides increases the porewater 56fe values as much as 0 68 more than corresponding sediment 56fe values the near surface fe sulfide precipitation delivers to the lagoon dissolved fe with slightly positive 56fe values averaging about 0 24 via submarine groundwater discharge sgd iron sulfide precipitation in sulfide containing subterranean estuaries thus may result in a previously unidentified source of isotopically heavy fe to the coastal oceans

iron isotopes in the early marine diagenetic iron cycle measurements of fe oxyhydroxides reactive fe iii in two shallow sediment profiles from reducing and oxic environments on the arabian sea margin demonstrate fe isotope fractionation during early marine diagenesis reactive fe iii has 56 fe values between 0 77 and 0 19 values are lowest at the top of the sediment profile and considerably lower than bulk sediment fe 56 fe 0 preferential reduction and dissolution of light fe isotopes during diagenesis leaves behind an increasingly smaller and heavier reactive fe iii residual initially the isotopic composition of reactive fe iii evolves down core according to the fractionation factor typical of microbial dissimilatory fe reduction deeper in the profile 56 fe values remain unchanged despite further fe reduction here another process with a different fractionation factor becomes dominant probably reduction by dissolved sulfide the 56 fe of the residual reactive fe iii suggests that 25 of the initially present reactive fe iii was reduced by microbial fe reduction when fe is diagenetically recycled between reducing sediments at depth and an oxic top layer the process depending on recycling efficiency may result in the accumulation of light fe in the top layer while the complementary heavier residual is buried fe diffusing from the seafloor back into the ocean should reflect the low 56 fe diagenetic source of dissolved fe

a multi level pore water sampler for permeable sediments abstract the construction and operation of a multi level piezometer multisampler designed to collect pore water from permeable sediments up to 230 cm below the sediment water interface is described multisamplers are constructed from 1 inch schedule 80 pvc pipe one quarter inch flexible pvc tubing leads from eight ports at variable depths to a 1 inch tee fitting at the top of the pvc pipe multisamplers are driven into the sediment using standard fence post drivers water is pumped from the pvc tubing with a peristaltic pump field tests in banana river lagoon florida demonstrate the utility of multisamplers these tests include collection of multiple samples from the permeable sediments and reveal mixing between shallow pore water and overlying lagoon water

dynamics governing the response of tidal current along the mouth of jiaozhou bay to land reclamation 7 abstract data collected from the previous studies show that the tidal current along the mouth of jiaoz 8 hou bay jzb appears to have weakened whereas the spatial asymmetry stronger flooding in the north 9 region and stronger ebbing in the south region has remained nearly unchanged during the past aq4 several 10 decades of large scale land reclamation this study is conducted to explain the underlying dynamics for this 11 phenomenon the analytic evaluation of the tidal motion indicates that the tidal current in a small coastal 12 bay such as the jzb is linearly proportional to its length l if l is far less than one quarter of the tidal wave 13 length this relation suggests that the decrease in tidal current speed in jzb mouth results from the land 14 reclamation within the bay also the relationship between bay areas and tidal current along the jzb mouth 15 can be derived the results of this simple theoretical method for predicting the change in mean tidal current 16 amplitude after the land reclamation largely agree with previous three dimensional 3 d modeling studies 17 it is also found that the spatial asymmetry of the tidal current along the jzb mouth is controlled by the 18 sharp headland the local factor the unchanged shoreline around the headland leads to the stable spatial 19 asymmetry of the tidal current the weaker tidal current can explain the weaker residual current and the 20 unchanged asymmetry of the tidal current explains the unaltered pattern of inflow over the north region

residence times of surface water and particle reactive 210pb and 210po in the east china and yellow seas 228ra 226ra 210pb and 210po were measured in the surface waters of the east china and yellow seas using mass balance equations for the ra isotopes we estimated the total flux of diffusion from sediments and desorption from suspended particles to be 0 1 dpm 226ra cm 2 a 1 and 1 dpm 228ra cm 2 a 1 and residence times to be 2 3 years for the waters on the east china sea shelf and 5 6 years for yellow sea waters box model calculations yielded generally congruent scavenging residence times for 210pb and 210po in the waters of 2 months on the shelf and 7 months in the kuroshio current these suggest that reactive heavy metals and pollutants discharged through rivers from the continent to the east asian continental shelf are largely deposited on the bottom sediments prior to transport to the pelagic ocean by lateral mixing

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

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

iron isotope fractionation during microbial reduction of iron the importance of adsorption in experiments investigating the causes of fe isotope fractionation the d 56 54 fe value of fe ii remaining in solution fe ii aq after reduction of fe iii goethite by shewanella putrefaciens is 21 2 relative to the goethite in agreement with previous research the addition of an electron shuttle did not affect fractionation suggesting that fe isotope fractionation may not be related to the kinetics of the electron transfer furthermore in abiotic anaerobic fecl2 aq experiments in which approximately one third of fe ii aq is lost from solution due to adsorption of fe ii onto goethite the d 56 54 fe value of fe ii aq remaining in solution is shifted by 20 8 relative to fecl 2 this finding demonstrates that anaerobic nonbiological interaction between fe ii and goethite can generate signif icant fe isotope fractionation acid extraction of sorbed fe ii from goethite in experi ments reveals that heavy fe preferentially sorbs to goethite simple mass balance modeling indicates that the isotopic composition of the sorbed fe ii pool is 11 5 to 12 5 heavier than fe in the goethite 2 7 3 7 heavier than aqueous fe ii mass balance is also consistent with a pool of heavy fe that is not released to solution during acid extraction

iron isotope systematics in estuaries the case of north river massachusetts usa abstract recent studies have suggested that rivers may present an isotopically light fe source to the oceans since the input of dissolved iron from river water is generally controlled by flocculation processes that occur during estuarine mixing it is important to investigate potential fractionation of fe isotopes during this process in this study we investigate the influence of the flocculation of fe rich colloids on the iron isotope composition of pristine estuarine waters and suspended particles the samples were collected along a salinity gradient from the fresh water to the ocean in the north river estuary ma usa estuarine samples were filtered at 0 22 m and the iron isotope composition of the two fractions dissolved and particles were analyzed using high resolution mc icp ms after chemical purification dissolved iron results show positive 56 fe values with an average of 0 43 0 04 relative to the irmm 14 standard and do not display any relationships with salinity or with percentage of colloid flocculation the iron isotopic composition of the particles suspended in fresh water is characterized by more negative 56 fe values than for dissolved fe and correlate with the percentage of fe flocculation particulate 56 fe values vary from 0 09 at no flocculation to 0 1 at the flocculation maximum which reflect mixing effects between river borne particles lithogenic particles derived from coastal seawaters and newly precipitated colloids since the process of flocculation produces minimal fe isotope fractionation in the dissolved fe pool we suggest that the pristine iron isotope composition of fresh water is preserved during estuarine mixing and that the value of the global riverine source into the ocean can be identified from the fresh water values however this study also suggests that 56 fe composition of rivers can also be characterized by more positive 56 fe values up to 0 3 relative to the crust than previously reported in order to improve our current understanding of the oceanic iron isotope cycling further work is now required to determine the processes controlling the fractionation of fe isotopes during continental run off

iron isotopes in the seawater of the equatorial pacific ocean new constraints for the oceanic iron cycle abstract this study presents the isotopic compositions and concentrations of dissolved and particulate iron from two seawater profiles of the western and central equatorial pacific ocean sampled during the eucfe cruise most of the 56 fe values are positive relative to irmm 14 from 0 01 to 0 58 in the dissolved fraction dfe and from 0 02 to 0 46 in the particulate fraction pfe the mean measurement uncertainty of 0 08 2sd allows the observation of significant variations most of the isotope variations occur in the vertical and not in the horizontal direction implying that each isotope signature is preserved over long distances within a water mass the thermocline waters of the papua new guinea png area mostly influenced by sedimentary inputs display a mean 56 dfe value of 0 37 0 15 2sd this isotopic signature suggests that the process releasing dissolved iron into the seawater in this area is a non reductive dissolution of sediments discharged by local rivers and likely re suspended by strong boundary currents rather than dissimilatory iron reduction dir within the sediment characterized by negative 56 dfe these positive 56 dfe values seem to be the result of a mean isotopic fractionation of 56 fe dfe pfe 0 20 0 11 2sd produced by the non reductive dissolution at 0 n 180 e the fe isotope signature of the equatorial undercurrent euc waters is identical to that of the png station within the range of the uncertainty this suggests that the dissolved iron feeding the euc and ultimately the eastern pacific high nutrient low chlorophyll area is of png origin likely released by a non reductive dissolution of terrigenous sediments significant fe removals are observed within the thermocline and the intermediate waters between the png and the open ocean stations the corresponding isotopic fractionations appear to be small with 56 fe removed sw fe values of 0 30 0 31 to 0 18 0 12 2sd for dfe removal and of 0 10 0 04 to 0 05 0 31 2sd for pfe removal in the chlorophyll maximum of the open ocean station the isotopic fractionation associated with biological uptake is estimated at 56 fe phyto dfe 0 25 0 10 to 0 13 0 11 2sd although these fractionations are based on a limited dataset and need to be further constrained they appear to be small and to limit the transformations of the iron source signatures within the ocean

fe isotope fractionation on fes formation in ambient aqueous solution iron sulfide phases are the ultimate repository of iron and reduced sulfur in sediments the sulfur isotope geochemistry of pyrite has had much to tell us about modern and ancient earth environments and it is likely that fe isotopes will too once fractionations for key processes are known we report the results of an experimental study of fe isotope fractionation on precipitation of fes synthetic mackinawite from excess aqueous fe ii solutions by addition of sodium sulfide solution at 2 40 c the results show a significant kinetic isotope effect in the absence of a redox process no detectable effect of temperature on the fractionation factor was observed the fe isotope fractionation for zero age fes is fe ii fes 0 85 0 30 across the temperature range studied giving a kinetic isotope fractionation factor of fe ii fes 1 0009 0 0003 on ageing the fes in contact with aqueous fe ii becomes progressively isotopically heavier indicating that the initial fractionations are kinetic rather than equilibrium from published reaction mechanisms the opportunity for fe isotope fractionation appears to occur during inner sphere ligand exchange between hexaqua fe ii and aqueous sulfide complexes fe isotope fractionation on mackinawite formation is expected to be most significant under early diagenetic situations where a readily available reactive fe source is available since fes aq is a key reactive component in natural pyrite formation kinetic fe isotope fractionations will contribute to the fe isotope signatures sequestered by pyrite subject to the relative rate of fes2 formation versus fes fe ii aq isotopic equilibration

enhanced cross shelf exchange by tides in the western ross sea 1 the western ross sea is one of the key sites for cross shelf water exchange around antarctica the mechanism through which tides affect the cross shelf exchange in the northwestern ross sea is investigated using numerical simulations tides are found to increase the high salinity shelf water hssw outflow through the impact on the warm water intrusion of open ocean origin the residual tidal currents are onshore along the modified circumpolar deep water pathway and therefore enhance its intrusion lighter ambient water adjacent to the hssw increases the cross flow density gradient thus strengthening the hssw export at the same time the onshore residual current and increased dilution of the hssw have the potential to reduce the export rate owing to the existence of opposite tidal effects the strongest hssw export happens at the intermediate tidal forcing strength the amplification of tides on cross shelf exchange indicates that the relevant dynamical processes should be simulated or parameterized in climate models in order to adequately predict the ocean

antarctic bottom water production and export by tides in the ross sea 1 current measurements in the western ross sea show that antarctic bottom water is produced at the outer edge of the continental shelf by tidal stirring of antarctic surface water circumpolar deep water and shelf water current amplitudes during spring tides are greater than 1 m s sufficient to carry circumpolar deep water onto the shelf from offshore and stir at least the lower portion of the water column to a nearly homogeneous mixture the antarctic bottom water produced every day during spring tides does not appear to have a seasonal signal its export rate is estimated to be 1 95 1 85 10 6 m 3 s

seasonal variations of the yellow river plume in the bohai sea a model study 1 we investigated the behavior of the yellow river plume in the bohai sea through a year and its controlling mechanisms using a numerical model driven by monthly averaged wind stress heat flux and river discharge the model produced a clear seasonal behavior of the yellow river plume in summer the yellow river plume extends northeastward into the central bohai sea in autumn it turns southward and flows into laizhou bay along the coast in winter most of the diluted water is found around southeastern corner of laizhou bay and in spring a low salinity area appears in southwest laizhou bay with the same model several well designed numerical experiments were performed to investigate the effect on the behavior of the yellow river plume of tidal current river discharge wind stress and thermal stratification the tidal currents promote the offshore spread of diluted water while the tide induced residual currents prevent the plume from extending further downstream in the direction of kelvin wave propagation wind stresses lead to pronounced changes in the path and shape of the plume in autumn and winter northwesterly or northerly winds drive the buoyant water into laizhou bay along the coast in summer the combination of southeasterly winds and thermal stratification drives the plume extend northeastward into the central bohai sea by changing only the magnitude of wind stress or river discharge in the experiments we examined the sensitivity of summertime plume to the magnitude of wind stress and river discharge

pore fluid fe isotopes reflect the extent of benthic fe redox recycling evidence from continental shelf and deep sea sediments pore fluid fe isotopes may be a unique tracer of sediment respiration by dissimilatory fe reducing bacteria but to date pore fluid fe isotope measurements have been restricted to continental shelf settings here we present 56fe values of pore fluids from two distinct sedimentary settings 1 a riverine dominated site on the northern california margin eel river shelf 120 m water depth and 2 biogenic opal rich volcaniclastic deep sea sediments from the southern ocean north and south of the crozet plateau 3000 4000 m water depth the fe isotope compositions of crozet region pore fluids are significantly less fractionated 56fe 0 12 to 0 01 than the eel river shelf 56fe 0 65 to 3 40 and previous studies of pore fluid fe isotopes relative to average igneous rocks our data represent the first measurements of fe isotope compositions in pore fluids from deep sea sediments a comparison of pore fluid 56fe with the relative abundance of highly labile fe in the reactive sedimentary fe pool demonstrates that the composition of fe isotopes in the pore fluids reflects the different extent of sedimentary fe redox recycling between these sites

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