comparison of water column co2aq with sedimentary alkenone based estimates a test of the alkenone co2 proxy 1 the stable carbon isotopic compositions of alkenones have been used to interpret the long term history of the partial pressure of atmospheric carbon dioxide pco2 although extensive water column and culture studies document the potential utility and limitations of this approach to date the accuracy of pco2 values derived from sedimentary alkenones remains untested for this study we establish holocene aged alkenone based co2aq estimates co2aq alk from 20 sites along a central pacific ocean transect and compare them against both observed modern water column co2aq and estimated preindustrial concentrations at the depth of alkenone production at each site although the co2aq alk track measured water column values they are conspicuously lower than modern values across the subtropics this offset likely reflects the contributions of anthropogenic co2 in modern surface waters relative to preindustrial concentrations at the time of alkenone production when a model based estimate of anthropogenic co2 is removed from the modern observed values a majority 84 of co2aq alk falls within 20 of modeled preindustrial values consistency between the modeled and alkenone based estimates of preindustrial co2 levels points to the relative accuracy of the alkenone co2 method across a wide range of ocean and biogeographic regimes provided that phosphate concentrations at the depth of haptophyte production are reasonably constrained it further suggests that light limited growth and or active carbon uptake if they occur have a negligible effect on reconstructed co2aq

dietary reconstruction of an early to middle holocene human population from the central california coast insights from advanced stable isotope mixing models the inherent sampling and preservational biases of the archaeological record make it difficult to quantify prehistoric human diets especially in coastal settings where populations had access to a wide range of marine and terrestrial food sources in certain cases geochemical proxies such as stable isotope ratios may be utilized to provide robust estimates on the relative proportions of various food resources consumed by prehistoric populations the harkins slough archaeological site scr 60 130 is an early to middle holocene coastal assemblage located on monterey bay in central ca the carbon d 13 c and nitrogen d 15 n isotope composition of human burials and associated archaeofauna excavated from the site were measured for input into a concentration dependent isotope mixing model that is able to statistically discriminate among multiple o3 food sources the human burials segregate into two distinct groups an early w7000 bp and middle w4500 bp holocene population with significant dietary differences stable isotope analyses indicate a 70e84 marine food source contribution for the early holocene group ehg but only a 48e58 marine dietary contribution for the middle holocene group mhg results also suggest that pinnipeds were an important marine food source for both groups modeling results are in agreement with archaeological evidence from southern ca suggesting that early holocene coastal populations were highly dependent on marine resources with the ability to procure both littoral and pelagic species further the use of terrestrial plant sources likely increased over time with the feasible contribution range doubling from the ehg 4e30 mean 19 to mhg 10e52 mean 38 this trend is supported by regional archaeological evidence for the advent of technological innovations linked to intensive terrestrial plant processing beginning in the middle holocene methodologically this work demonstrated the utility of a concentration dependent stable isotope mixing model in an iterative framework to provide feasible ranges of dietary contribution when the number of food sources is too high to allow a unique solution 2004 published by elsevier ltd

evidence for preindustrial variations in the marine surface water carbonate system from coralline sponges 1 coralline sponge skeletons are excellent tools for reconstructing the carbon isotope history of dissolved inorganic carbon dic in tropical surface waters carbon isotope records from coralline sponges clearly reflect the industrial 12c increase in atmospheric co2 with a precision that permits quantitative interpretations we find from a set of 13c records of four caribbean sponge specimens that the isotopic response of surface water dic to the changing isotopic composition of atmospheric co2 varied dynamically during the last century depending on the rate of atmospheric change three of our sponges provide 600 year long 13c records for the first time we can reconstruct surface water 13cdic for the full history of the industrial co2 release as well as the preceding preindustrial period back to the beginning of the little ice age this provides a well founded estimate of the anthropogenically uninfluenced preindustrial background level of surface water 13c 12c ratios our records show small but systematic variations that appear to be linked to the climate fluctuations of the little ice age

weakening of the kuroshio intrusion into the south china sea over the past two decades inferred from the satellite and in situ hydrographic data from the 1990s and 2000s the kuroshio intrusion into the south china sea scs had a weakening trend over the past two decades associated with the weakened kuroshio intrusion the kuroshio loop and eddy activity southwest of taiwan became weaker whereas the water above the salinity minimum became less saline in the northern scs the sea surface height southwest of taiwan increased at a slower rate compared to other regions of the scs because of the weakened kuroshio intrusion simulations using the regional ocean modeling system roms pacific model show that the strength of the kuroshio intrusion into the scs decreased from 1993 to 2010 with a negative trend 0 24 sverdrups sv yr 1 1 sv 10 6 m 3 s 1 in the total luzon strait transport lst although wind induced ekman transport through the luzon strait became weaker the magnitude at 0 001 sv yr 1 was too small to compensate for the negative trend of the lst on the other hand the piling up of the water induced by monsoon winds was an important mechanism for changing the pressure gradient across the luzon strait and eventually affecting the lst the sea level gradient between the western pacific and the scs had a negative trend 0 10 cm yr 1 corresponding to a negative trend in the geostrophic transport at 0 20 sv yr 1 the kuroshio transport east of luzon island also had a negative trend which might also be linked to the weakening kuroshio intrusion

multidecadal changes of upper ocean thermal conditions in the tropical northwest pacific ocean versus south china sea during 1960 2015 abstractby analyzing the upper ocean properties of observation based hydrographic data and validated oceanic reanalysis products this study presents multidecadal changes of oceanic surface and sub

marine climate variability during the last millennium the loch sunart record scotland uk abstract the first decadal scale reconstruction of british coastal temperature anomalies spanning the last millennium is presented from a sea loch fjord basin loch sunart nw scotland based on modern observation and the results of previous numerical modeling of fjord circulation benthic foraminiferal oxygen isotope records are interpreted as a record of summer temperature a significant climate transition apparently driven by large scale reorganization of northern hemisphere atmospheric circulation occurs in the record around ad 1400 an abrupt but relatively short lived climate warming occurs between ad 1540 1610 when the bottom water temperature anomalies are 1 1 c above the long term average which is warmer than most of the 20th century and the late medieval warm period a long term cooling occurs throughout the little ice age culminating in the coldest recorded temperature anomalies between the late 1920s and 1940s the warmest reconstructed temperatures of the past millennium occurred in the last 5 years of the record which ends in 2006 a replicated post ad 1900 shift in benthic foraminiferal 13 c of ca 0 6 provides evidence of the oceanic 13 c suess effect this feature provides an independent test of the age model and demonstrates the value of benthic foraminifera as palaeo proxies in the loch sunart record

foraminiferal radiocarbon record of northeast pacific decadal subsurface variability 1 the decadal dynamics of the subsurface north pacific ocean are largely inaccessible beyond sparse instrumental observations spanning the last 20 years here we present a 200 year long record of benthic foraminiferal radiocarbon 14c extracted at biennial resolution from the annually laminated sediments at the santa barbara basin sbb depocenter 600 m the close match between core top benthic foraminiferal 14c values and the 14c of seawater dissolved inorganic carbon dic suggests that benthic foraminifera faithfully capture the bottom water radiocarbon concentrations as opposed to that of the deeper 0 5 cm sediment porewater zone the full time series of benthic foraminiferal 14c displays significant variability on decadal timescales with excursions on the order of 40 these excursions are overprinted by a unidirectional trend over the late 20th century that likely reflects the sedimentary incorporation of bomb radiocarbon via remineralized particulate organic carbon we isolate this trend by means of a one dimensional oxidation model which considers the possible contribution of remineralized particles to the total ambient carbon pool this oxidation model also considers the possible influence of carbon with a variety of sources ages though variable oxidation of preaged carbon could exert a strong influence on benthic foraminiferal radiocarbon variability the totality of evidence points to the vertical density structure along the southern california margin scm as the primary driver of the sbb benthic foraminiferal 14c record for example intervals characterized by significantly lower 14c values correspond to periods of enhanced upwelling and subsurface equatorward flow along the scm

decadal changes in tropical cyclone activity over the western north pacific in the late 1990s a pronounced decadal change in tropical cyclone tc activity over the western north pacific wnp in the late 1990s was identified based on a comparison of the two epochs that occurred before and after the late 1990s the tc genesis number exhibited an evident decrease over the southern wnp s wnp 5 20 n 105 170 e and an increase over the northern wnp n wnp 20 25 n 115 155 e which partly corresponded to a significant northward migration in the seasonal mean latitudinal location of tc genesis i e from 17 2 n to 18 7 n after the late 1990s the northwestward moving track became the most dominant track mode accompanied by the weakening of both the westward moving track and the northeastward recurving track meanwhile the tc occurrence frequency tcf experienced evident increases over southeastern china and the okinawa islands while prominent decreases occurred over the south china sea the philippine sea japan and east of japan changes in the tcf were determined by tc genesis changes tc track shifts and variations in regional tc durations which were all ascribed to the decadal change in tropical indo pacific sea surface temperature the full picture on the decadal changes in the wnp tc activity revealed in this study may provide useful guidance for regional tc seasonal forecasts and future projections

mixed layer thermodynamics of the southern south china sea seasonal and inter annual variability of the mixed layer temperature in the southern south china sea sscs is investigated using a regional ocean circulation model simulation the mixed layer depth mld over the sscs exhibits a strong seasonal signal with deeper mlds during the northeast and southwest monsoons the main factor that drives the mixed layer temperature variation in the sscs is the air sea heat fluxes with vertical ocean processes acting as a relatively weak negative feedback in general the budget analysis demonstrates a net balance between the vertical ocean processes and surface heat flux during the pre monsoon and southwest monsoon northeast monsoon period is noted by an offsetting of surface heat flux horizontal and vertical ocean processes the first dominant mode of mixed layer temperature inter annual variability in the sscs shows significant correlation 0 34 with the el nino phenomenon in the pacific ocean and is best correlated 0 67 with a lag of 5 months

tracing the thermohaline circulation in the western north atlantic using chlorofluorocarbons abstract measurement of chlorofluorocarbons cfcs f 11 and f 12 were obtained from vertical sections extending across the deep western boundary current dwbc along the western margin of the north atlantic ocean between 32 45 n in 1983 and 1986 these sections revealed an upper and a deep cfc maximun with highest concentrations along the continental slope the upper maximum had a potential temperature ranging from 4 2 4 6 c a core density of 1 5 34 56 and occurred at a depth of about 800m adjacent to the continental slope water with classical labrador sea water s characteristics occurs just above the cfc minimum between the upper and lower maxima and indicates that a significant volume of classical labrador sea water has not entered the region south of the grand banks for the last 3 decades the deep cfc maximum is from dense water overflowing the greenland iceland scotland ridge it occurred at about 3500m depth and had a potential temperature range of 2 02 2 18 c and a core density of 4 45 87 a source function of f 11 and f 12 for the deep maximum was estimated using temperature salinity and tracer data from previous studies the core of the dwbc defined by the deep cfc maximum was estimated to consist of roughly 2 3 gibbs fracture water and 1 3 denmark strait overflow water however 80 or more of the f 11 and f 12 signal was derived from denmark strait overflow water ages for the upper and lower cfc maxima in the dwbc were estimated from the cfc data these ages ranged from 11 12 years at the northernmost section to 18 years at the southernmost section for both features this corresponds to apparent mean current speeds of about 0 8cm s 1 for the upper maximum and 1 4cm s 1 for the deep maximum an age of 8 9 years with a corresponding apparent mean current speed of 2 2 2 5cm s 1 was also estimated for the deep cfc maximum from the observed increase in the f 11 concentration at 41 n between 1983 and 1986 the apparent mean current speeds are significantly less than current speeds measured with long term current meter moorings two reasons for this are 1 mixing between the dwbc core and adjacent water causes ages estimated from cfc data to be overestimated and hence the associated current speed to be underestimated pickart hogg and smethie 1989 and 2 water propagating along the western boundary spends some time in recirculation gyres the northern recirculation gyre south of the eastern north american continental margin is clearly apparent in the lateral distributions of f 11 and f 12 the apparent mean current speed in the northern recirculation gyre was estimated to be 1 3cm s 1 from the cfc data seaward of the dwbc north of the new england seamount chain high cfc low silica parcels of water were observed interspersed with low cfc high silica parcels of water along the bottom the high cfc low silica water is overflow water with a slightly greater component of denmark strait overflow water than contained in the dwbc deep cfc maximum the low cfc high silica water is of southern origin and has a component of antarctic bottom water

isotopic composition of conomurex fasciatus shells as an environmental proxy for the red sea abstract the marine gastropod conomurex fasciatus born 1778 is the main component of thousands of shell middens on the farasan islands in the southern red sea the middens date from 6500 to 4500 cal bp and cover the period of increased aridification over the region no general research on c fasciatus has been carried out before and basic information about the species is mostly speculative to test if c fasciatus shells can be used as a recorder of climate variability we collected living specimens from the farasan islands in saudi arabia over a 1 5 year period this area receives almost no precipitation and sea surface salinity is extremely high 38 39 psu and sea surface temperature sst ranges from 26 5 c to 34 9 c raman spectroscopy results on modern c fasciatus shell samples show these specimens to be aragonitic ground fragments from archaeological c fasciatus shells used for isotope analyses were also measured by raman spectroscopy and shown to be well preserved against diagenetic alterations leading to aragonite to calcite transformation measured shell edge 18o values range from 0 5 to 1 7 calculated modern shell edge temperatures from these 18o values correlate with modern sst measured on site with an error of 2 4 c two different growth rates occurred in the shells of c fasciatus the measurement of growth increments in the lip part of adult specimens indicates a tide related growth rate of 13 mm year sequential 18o data from juvenile parts of the shell indicates a faster growth rate of 90 mm year this growth rate and the correlation of 18o with measured temperatures allows the use of c fasciatus shell 18o as a palaeoclimate proxy

interannual variability of the south china sea throughflow inferred from wind data and an ocean data assimilation product 1 the luzon strait transport as an index for the south china sea throughflow has attracted much attention recently in this study the interannual variability of luzon strait transport is examined using the island rule and results from ocean data assimilation transport variability obtained from these two approaches is consistent with each other assessment of contribution from each integral segment involved in the island rule indicates that wind stress in the western and central equatorial pacific is the key factor regulating the interannual variability of the luzon strait transport whereas the effect of local wind stress in the vicinity of the luzon strait is secondary analysis also shows that when the westerly easterly wind anomalies in the tropical pacific break out the luzon strait transport increases decreases associated with the variations in the

tropical indian ocean influence on northwest pacific tropical cyclones in summer following strong el nino abstract in the summer following a strong el nino tropical cyclone tc number decreases over the northwest nw pacific despite little change in local sea surface temperature the authors analysis suggests el nino induced tropical indian ocean tio warming as the cause the tio warming forces a warm tropospheric kelvin wave that propagates into the western pacific inducing surface divergence off the equator the tropospheric kelvin wave suppresses convection and induces an anomalous anticyclone over the nw pacific both anomalies unfavorable for tcs the westerly vertical shear associated with the warm kelvin wave reduces the magnitude of vertical shear in the south china sea and strengthens it in the nw pacific an east west variation that causes tc activity to increase and decrease in respective regions these results help improve seasonal tc prediction

oceanic penetration of excess co2 in a cross section between alaska and hawaii results from the recent co sub 2 dynamics cruise in the northeast north pacific ocean june july 1981 are presented the shipboard co sub 2 data indicate that the excess co sub 2 has penetrated to the deepest depth 1000 300 m near the subtropical front but to a shallower depth outside of the frontal zone in general the depth of penetration is several hundred meters shallower than in the northwest pacific

depth distributions of alkalinity tco2 and δ13ctco2 at seats time series site in the northern south china sea abstract in this study measurements of titration alkalinity ta total dissolved carbon dioxide tco2 and 13c of tco2 13 c tco 2 throughout the water column at the southeast asian time series study seats site were investigated in order to understand better the fundamental processes controlling their vertical distributions in the south china sea scs the linear correlations between ta and salinity in the shallow waters as identified by the mixing line between the surface water and salinity maximum water suggested the predominant control of physical mixing on the variability of ta in contrast tco2 and 13 c tco 2 showed the non conservative behavior in the respective tco2 and 13 c tco 2 vs salinity plot due to the effect of biological production a stoichiometric model further showed that the depth profile of nta ta salinity 35 largely reflects the increase of preformed nta in the shallow waters whereas carbonate dissolution was responsible for the continuous increase of nta in the deep waters a one dimensional diffusion advection model further revealed that the carbonate dissolution could account for 28 of ntco2 tco2 salinity 35 increase in deep waters and the remaining 72 of ntco2 was from organic decomposition calculation of excess ta further showed that it emerged well above the aragonite and calcite saturation depths at 600 and 2500 m respectively indicating that some biologically chemically and physically mediated processes must be involved to provide excess ta into the shallow waters the decrease in 13 c tco 2 with depth primarily resulted from organic decomposition the influence of anthropogenic co2 throughout the water column was assessed with the carbon chemistry and the isotope based approach in this study both methods obtained nearly the same results in which the signal of anthropogenic co2 decreased exponentially with depth and its penetration depth were found to be at 1000 m the inventory of anthropogenic co2 in the water column was estimated to be 16 6 mol c m 2 which was less than that reported in the northwest pacific at the same latitude presumably due to the enhanced upwelling in the scs such an anthropogenic co2 penetration had led to decreases of the saturation levels of aragonite and calcite by 17 and 14 respectively in the surface water and an upward migration of aragonite saturation depth by 100 m since industrial revolution

mechanism of seasonal eddy kinetic energy variability in the eastern equatorial pacific ocean enhanced mesoscale eddy activities or tropical instability waves tiws exist along the northern front of the cold tongue in the eastern equatorial pacific ocean in this study we investigate seasonal variability of eddy kinetic energy eke over this region and its associated dynamic mechanism using a global eddy resolving ocean general circulation model ogcm simulation the equatorial mooring data and satellite altimeter observations the seasonal varying enhanced eke signals are found to expand westward from 100 w in june to 180 w in december between 0 6 n this westward expansion in eke is closely connected to the barotropically baroclinically unstable zonal flows that are in thermal wind balance with the seasonal varying thermocline trough along 4 n by adopting an 1 layer reduced gravity model we confirm that the seasonal perturbation of the thermocline trough is dominated by the anti cyclonic wind stress curl forcing which develops due to southerly winds along 4 n from june to december

indian ocean capacitor effect on indo western pacific climate during the summer following el nino significant climate anomalies persist through the summer june august after el nino dissipates in spring over the equatorial pacific they include the tropical indian ocean tio sea surface temperature sst warming increased tropical tropospheric temperature an anomalous anticyclone over the subtropical northwest pacific and increased mei yu baiu rainfall over east asia the cause of these lingering el nino effects during summer is investigated using observations and an atmospheric general circulation model gcm the results herein indicate that the tio warming acts like a capacitor anchoring atmospheric anomalies over the indo western pacific oceans it causes tropospheric temperature to increase by a moist adiabatic adjustment in deep convection emanating a baroclinic kelvin wave into the pacific in the northwest pacific this equatorial kelvin wave induces northeasterly surface wind anomalies and the resultant divergence in the subtropics triggers suppressed convection and the anomalous anticyclone the gcm results support this kelvin wave induced ekman divergence mechanism in response to a prescribed sst increase over the tio the model simulates the kelvin wave with low pressure on the equator as well as suppressed convection and the anomalous anticyclone over the subtropical northwest pacific an additional experiment further indicates that the north indian ocean warming is most important for the kelvin wave and northwest pacific anticyclone a result corroborated by observations these results have important implications for the predictability of indo western pacific summer climate the spatial distribution and magnitude of the tio warming rather than simply whether there is an el nino in the preceding winter affect summer climate anomalies over the indo western pacific and east asia

interannual to decadal variability and trends of sea level in the south china sea interannual to decadal variability and trends of sea level in the south china sea scs are studied using altimetric data during 1993 2012 and reconstructed sea level data from 1950 2009 the interannual variability shows a strong seasonality surface wind anomalies associated with el nino southern oscillation explain the sea level anomaly pattern in the interior scs while rossby waves radiated from the eastern boundary dominate the sea level variability in the eastern scs decadal variability of sea level in the scs follows that in the western tropical pacific with large variance found west of luzon island local atmospheric forcing makes a negative contribution to decadal variability in the central scs and rossby waves radiated from the eastern boundary appear to be important during 1993 2012 decadal sea level averaged in the scs is significantly correlated with the pacific decadal oscillation pdo r 0 96 the decadal variability associated with the pdo accounts for most part of sea level trends in the scs in the last two decades

low frequency variability of the north pacific ocean the roles of boundary and wind driven baroclinic rossby waves 1 the effects of the sea level variability along the eastern boundary of the north pacific ocean including those associated with el nino southern oscillation have been considered an important factor in determining the low frequency large scale variability of the ocean interior through rossby waves generated at the eastern boundary this hypothesis is examined in this study using 8 years worth of the sea surface height observations made by the topex poseidon satellite the timescales of interest are longer than 90 days with the annual cycle removed the results indicate that the influence of the eastern boundary of the north pacific ocean has limited offshore extent varying from 3000 4000 km at 10 n to 200 300 km at 50 n the variability in the ocean interior is primarily driven by wind with only a minor influence from the boundary simulations of a linear two layer model of the ocean driven by wind stress curl are correlated with the observations the effects of wind forcing accumulate along the characteristics of long nondispersive rossby waves in the time longitude domain these wind driven rossby waves overwhelm the boundary driven waves in the ocean interior where there are only some small residual effects of the boundary driven waves however these small effects become clearer after the simulated wind driven variability is removed from the observations index terms 4556 oceanography physical sea level variations 4504 oceanography physical air sea interactions 0312 4215 oceanography general climate and interannual variability 3309 keywords rossby waves satellite altimetry el nino north pacific eastern boundary

temporal and spatial variabilities of the south china sea surface temperature anomaly in this study we use the national centers for environmental prediction ncep monthly sea surface temperature sst fields 1982 1994 to investigate the temporal and spatial wriabilities of the south china sea scs warm cool anomalies three steps of analysis were performed on the data set ensemble mean t composite analysis to obtain the monthly mean anomaly relative to the ensemble mean t and empirical orthogonal function eof analysis on the residue data relative to t t the ensemble mean sst field t has a rather weak horizontal gradient 29oc near the borneo cost to 25o 26oc near the southeast chincoast two areas of evident sst anomalies were found in the monthly t variation west of borneo palawan islands wbp and southeast of the southern vietnam coast svc four patterns monsoon and transition each with two out of phase structures were found during the spring to summer transition march to may the warm anomaly is formed in the northern scs with t 1 8oc located at 112o 119o30 e 15o 19o30 n during the fml to winter transition october to november the northern scs north of 12on cool anomaly is formed in november with t 0 6oc located at 108o 115oe 13o 20on we performed an eof analysis on the residue data relative to t t in order to obtain transient and interannual variations of the sst fields eof1 accounts for 47 of the variance and represents the northern scs warm cool anomaly pattern eof2 accounts for 14 of the variance and represents the southern scs dipole pattern strong northern scs wrmnommy ioc wrmer ppers during october november 1987 nd jnury february 1988 and strong northern scs cool anomaly ioc cooler occurs during march 1986 and november 1992 furthermore strong cross correlation between wind stress curl and sst anomalies computed from the european centre for medium range weather forecast analyzed wind stress data and the n cep sst data for different lags shows the existence of an air sea feedback mechanism in the scs deep basin

interannual variability of the south china sea in a data assimilation model 1 sea surface height ssh variations in the south china sea are examined using results from a data assimilation model after the ssh data have had the annual cycle removed principal component analysis illustrates two distinct anomaly patterns the first mode strongest off vietnam would affect the basin wide gyre intensity the second mode consists of a meridional dipole feature with a nodal line around 12 n and is related to the development of the eastward jet and upwelling off vietnam both eof modes have significant interannual variations and are highly correlated to the enso events the leading phase of mode 2 coefficient provides preliminary evidence for the air sea interaction and the pacific east asian teleconnection an innovative mechanism is proposed to describe a weakened upwelling off luzon in winter 1998 an extra strong basin wide warming in summer 1998 persists into fall and winter preventing the formation of winter upwelling off luzon in that year

sclerochronology of busycon sinistrum late prehistoric seasonality determination at st joseph bay florida usa abstract recent archaeological investigations indicate that coastal fort walton cultures in the st joseph bay region of northwest florida emphasized marine and estuarine foraging these late prehistoric mississippi period a d 1000 1500 peoples collected fish shellfish and other aquatic resources at the richardson s hammock site 8gu10 radiocarbon dated to about a d 1300 large predatory gastropods were a major subsistence component this adaptation is in sharp contrast with that of contemporaneous inland fort walton societies who relied on maize agriculture and raises the question whether coastal groups were separate hunter gatherer fisher populations or migrated seasonally from inland farming villages we perform stable oxygen and carbon isotope sclerochronology on lightning whelks busycon sinistrum to determine the seasonality of fort walton foraging and to compare the environment of prehistoric st joseph bay with that of the modern bay oxygen isotope profiles suggest that shellfish collecting was relegated primarily to the summer months producing a scheduling conflict with the primary growing season for maize in northwest florida thus coastal and inland fort walton sites probably represent separate culture groups the relationship between 18oshell and 13cshell indicates similar environmental and climatic conditions between prehistoric st joseph bay and today however modern whelks are depleted in 13c compared to fort walton whelks which reflects both twentieth century co2 emissions and years of dredging and wastewater pollution entering the bay

13c constraints on ocean carbon cycle models 1 the sensitivity of oceanic 13c fields to overturning and gas exchange is investigated in a suite of ocean general circulation models the deep and oceanic mean 13c in the models was sensitive to the balance between deep waters forming in the north atlantic and the southern ocean increasing the southern ocean deep water formation rate to improve deep sea 14c and aou fields was detrimental to model data 13c fidelity a concurrent increase in north atlantic deep water would be needed to match the observed 14c and 13c constraining both the rate and schematics of model deep water formation respectively and improving sensitivity to future perturbations inter basin trends in 13c were sensitive to the rate of overturning in the models with high mixing model configurations matching the observations best models anthropogenic 13c changes used as a diagnostic of model co2 uptake were in agreement with the observations except at high southern latitudes 50 s where the model 13c changes were greater than observed there were predictive relationships among models uptake of anthropogenic co2 and depth integrated 13c changes model relationships between model anthropogenic co2 uptake and the air sea 13c disequilibrium and the sea surface 13c depend on preindustrial riverine fluxes of terrestrial organic carbon and on the wind field used to drive the model circulation respectively among the models tested the relations among anthropogenic co2 uptake and 13c changes in the ocean are biased by the ocmip practice of driving model momentum with one wind field and gas exchange rates with another

shell sclerochronology and stable isotopes of the bivalve anomalocardia flexuosa linnaeus 1767 from southern brazil implications for environmental and archaeological studies abstract this study presents the first stable isotopic and sclerochronological calibration of the bivalve anomalocardia flexuosa linnaeus 1767 in relation to environmental variables in a subtropical coastal area of southern brazil we investigate incremental shell growth patterns and 18o and 13c values of modern specimens collected alive from the laguna lagoonal system lls shells of anomalocardia flexuosa are also one of the main biological components of pre columbian archaeological shell mounds and middens distributed along the brazilian coastline we therefore selected archaeological specimens from a local late holocene shell mound cabecuda to compare their stable carbon and oxygen isotope values with those of modern specimens shell growth increments 18o and 13c values respond to a complex of environmental conditions involving for example the effects of temperature and salinity the isotopic information extracted from archaeological specimens from cabecuda shell midden in the lls indirectly indicates that environmental conditions during the late holocene were different from present day in particular intra shell 18o and 13c values of archaeological shells reveal a stronger marine influence at 3 ka cal bp which is in contrast to the seasonal freshwater seawater balance that currently prevails at the lls

salt usually seals but sometimes leaks implications for mine and cavern stabilities in the short and long term abstract thick evaporite masses bedded and halokinetic dominated by the mineral halite are currently mined using conventional solution mining techniques after excavation the resulting salt cavities are sometimes used as subsurface storage vessels for hydrocarbons or various types of waste including low level nuclear waste there are plans being discussed to use purposed designed solution cavities in thick salt masses for the long term storage of high level nuclear waste if high level nuclear waste is ever to be safely stored in salt it will involve a need for the encasing salt not to leak over time frames measured in tens of thousands of years understanding how where and why accessible salt masses leak is the rationale for this review it is the first step in assessing it a particular site s salt geology is suitable for storage we know salt can act as an excellent longterm seal over hundreds of thousands of years as evidenced by its ability to hold back significant columns of highly overpressured fluids even in structurally complex settings but we also know that locally salt bodies do occasionally leak large volumes of fluid as evidenced by the loss of a number of salt mines to uncontrolled floods the rapid creation of solution dolines atop subcropping salt masses and to black salt haloes around highly pressurized hydrocarbon reservoirs these types of leakage are usually tied to the edges of a salt body being exposed to longterm crossflows of undersaturated pore waters or to the build up of internal pressure to levels that exceed lithostatic in fact most zones where a salt body is liable to leak or has leaked are indicated by anomalous textural or mineralogical features when compared to the regional character of the salt the time of leakage can be early eogenetic related to burial mesogenetic or related to uplift telogenetic if the salt mass is not entirely dissolved in the fluid crossflow then the remaining salt tends to re seal especially in zones of ongoing salt flow however if non salt sediment remains in the re annealed salt mass it will tend to retain permeability and when intersected in a salt mine or by a well bore it will flow fluid more problematic in terms of significant leakage are zones in contact with an aquifer external to the salt mass these anomalous areas can transfer large volumes of fluid for this reason active telogenetic anomalies in a salt mass are the most problematic in terms of both mine safety and waste storage identifying the type of salt anomaly the time in diagenesis when leakage occurred and proximity and volume of intersected fluids in the zone of leaking salt is fundamental to mine safety and reliable waste storage

upper layer circulation in the south china sea abstract upper layer circulation is investigated by using all available historical temperature profiles combined with climatological temperature salinity relationships in the south china sea two cyclonic eddies are revealed one is located east of vietnam called the east vietnam eddy and the other is off northwest luzon called the west luzon eddy both local ekman pumping and remotely forced basin scale circulation are important mechanisms controlling these two eddies the luzon strait transport relative to 400 db is estimated to be of the order 3 0 sv 1 sv 1 106 m3 s 1 in the mean and has a seasonal cycle dominated by the annual signal with a maximum 5 3 sv in january february and a minimum 0 2 sv in june july pressure gradients are also examined to explore the dynamics of the intrusion of waters from the pacific into the south china sea through the luzon strait

strontium isotopic signatures of oil field waters applications for reservoir characterization the 87sr 86sr compositions of formation waters that were collected from 71 wells producing from a pennsylvanian carbonate reservoir in new mexico display a well defined distribution with radiogenic waters up to 0 710129 at the updip western part of the reservoir grading downdip to less radiogenic waters as low as 0 708903 to the east salinity 2800 50 000 mg l displays a parallel trend saline waters to the west pass downdip to brackish waters elemental and isotopic data indicate that the waters originated as meteoric precipitation and acquired their salinity and radiogenic 87sr through dissolution of upper permian evaporites these meteoric derived waters descended perhaps along deeply penetrating faults driven by gravity and density to depths of more than 7000 ft 2100 m the 87sr 86sr and salinity trends record influx of these waters along the western field margin and downdip flow across the field consistent with the strong water drive potentiometric gradient and tilted gas oil water contacts the formation water 87sr 86sr composition can be useful to evaluate subsurface flow and reservoir behavior especially in immature fields with scarce pressure and production data in mature reservoirs sr isotopes can be used to differentiate original formation water from injected water for waterflood surveillance strontium isotopes thus provide a valuable tool for both static and dynamic reservoir characterization in conjunction with conventional studies using seismic log core engineering and production data roger barnaby has conducted stratigraphic studies of carbonates and siliciclastics in outcrop and subsurface for 15 years he holds a ph d from virginia polytechnic institute and a b s degree from east carolina university barnaby has worked on sedimentary successions of the gulf coast permian basin alaska north slope middle east and caspian region he maintains interests in carbonate diagenesis and geochemistry gregg oetting received an m a degree in geology in 1995 from the university of texas at austin he is the author of six publications concerning geochemical and strontium isotopic variations in edwards aquifer groundwaters for the past seven years oetting has traded energy futures for leading merchant energy concerns he works for an independent consulting business in houston texas guoqiu gao received his b s and m s degrees in geology from central south university hunan china and his ph d in geology from the university of texas at austin he works for a major oil company in houston texas his current interests lie in the field of geoscience computing

upwelling in the continental shelf of northern south china sea associated with 1997 1998 el nino 1 a strong upwelling off the continental shelf of the northern south china sea scs in 1998 summer is reinvestigated using a suite of new satellite measurements and numerical modeling previous studies indicate that the upwelling in the western scs especially off the vietnam coast almost disappears during 1998 summer following the el nino because of the weakened southwest monsoon this study identifies that the coastal upwelling in the adjacent northern scs nscs is significantly strengthened during 1998 summer and the alongshore wind stress is dramatically enhanced over the region as a result the offshore ekman transport in 1998 summer is the strongest almost twice the average of the other 17 years during 1997 2007 the chl a concentrations in the representative upwelling regions are much higher than any in other years further analysis suggests that two adjacent basin scale upwellings in the scs have different responses and maintaining mechanisms because of the anticyclonic atmospheric circulation anomaly over the scs and northwest pacific the northern flank of the atmospheric circulation anomaly intensifies the monsoonal winds off the nscs coast while the southern flank suppresses the southwesterly winds along the vietnam coast

interannual mode of sea level in the south china sea and the roles of el nino and el nino modoki 1 enso scale variation of the summer ocean circulation in the south china sea scs is investigated the interannual mode of ssh features a north south dipole pattern that modulates the cold jet off vietnam during the summers before and after the el nino the mode has opposite signs of extrema strengthened circulations couple with the cold sstas during the el nino developing summers weakened circulations accompany the warm sstas during the decaying summers heat advection by the basin circulation modulates the sst variation the impact of the 1997 el nino on the scs circulation contrasting that of 1994 and 2002 el nino modoki is assessed with moderate sst warming but further westward shift of the low level convergence of the atmosphere in the equatorial pacific the el nino modoki phenomenon enhanced the western north pacific summer monsoon inside the scs driving stronger circulations in both the summers of 1994 and 2002

reconstructing the oceanic 13c suess effect the anthropogenic 13c change for the time period 1968 to 1991 was determined based on calculations of the preformed 13c 12c of dissolved inorganic carbon dic distributions on isopycnal surfaces in the main thermocline of the pacific north atlantic and south indian oceans the time rate of change of preformed 13c the 13c suess effect along isopycnals was calculated using cfc derived water ages and yields a time history of the surface water 13c change at the isopycnal outcrop location the surface ocean suess effect recorded on isopycnals decreased with increasing outcrop latitude from approximately 0 2 decade 1 within the subtropics to around 0 1 decade 1 in the subpolar oceans in the pacific ocean these surface 13c change rate reconstructions agree both in magnitude and meridional trend with direct observations of surface ocean 13c changes reported from time series measurements and from comparisons of surface water 13c of dic measurements in 1970 and 1993 a global ocean average surface 13c rate of change of 0 15 0 04 decade 1 is determined which is slightly smaller than a previous time series data and model based estimate 0 171 decade 1 bacastow etal 1996 depth integrations of the 13c reconstructions in the pacific indian and atlantic oceans when combined with these previous individual depth profile comparisons and geochemical ocean sections study bomb 14c inventories quay et al 1992 imply a global depth integrated 13c change rate of 9 7 2 4 m yr 1 over the time period 1970 1990 these results imply a net oceanic co2 uptake rate of 1 9 0 9 gt c yr 1 over the time period 1970 1990 when applied to an atmospheric 13co2 and 12co2 budget

oceanic radiocarbon separation of the natural and bomb components an improved method has been developed for the separation of the natural and bomb components of the radiocarbon in the ocean the improvement involves the use of a very strong correlation between natural radiocarbon and dissolved silica this method is applied to radiocarbon measurements made on samples collected during the geochemical ocean sections study geosecs transient tracers in the ocean tto and south atlantic ventilation experiment save expeditions on the basis of this new separation we provide not only an estimate of the global inventory of bomb 14c at the time of the geosecs survey but also the distribution of bomb radiocarbon along four thermocline isopycnals in each ocean we also document the evolution of the bomb 14c inventory and penetration along thermocline isopycnals in the north atlantic ocean between the times of the geosecs 1972 1973 and tto 1980 1982 surveys and in the south atlantic ocean between the times of the geosecs 1973 and save 1987 1989 surveys in addition we show that the bomb tritium to bomb 14c ratio expressed in the tritium unit tu 81 units 100 for waters entering the thermocline of the northern hemisphere is about 9 times higher than for those entering the southern hemisphere thermocline this contrast offers long term potential as an indicator of inter hemispheric transport of upper ocean waters

contribution of the phase transition of pacific decadal oscillation to the late 1990s shift in east china summer rainfall based on our previous study the interdecadal changes in summer rainfall over east china in the late 1990s are further explored here the increased local rising motion is implicated as the dominant factor of increased rainfall in the lower huang huai river valley lhr both the observation and numerical experiments using community atmosphere model version 4 suggest that the negative pacific decadal oscillation pdo mode can result in rising anomalies and thus more rainfall in the lhr the east asian westerly jet stream eawjs is suggested as a bridge to link the pacific sea surface temperature anomalies and east asian summer rainfall model results reveal that the negative pdo mode can lead to significant easterly anomalies over east asia as a result the eawjs is weakened and shifts poleward which coincides with observed changes in eawjs after the late 1990s in addition weakened and poleward shifted eawjs can result in an anomalous ascending motion to its south in the lhr by modulating the jet related secondary meridional vertical circulation consequently rainfall increased in the lhr after the late 1990s besides the positive atlantic meridional oscillation can only induce insignificant changes over east asia and partly counteract the negative pdo effect there

regional dynamics of seasonal variability in the south china sea abstract dynamics of the seasonal cycle of sea surface height ssh in the south china sea scs are studied using observations as well as numerical and theoretical models seasonal variability of the scs is interpreted in light of large scale dynamics and rossby waves it is found that the seasonal cycle over most of the scs basin is determined predominantly by the regional ocean dynamics within the scs the ssh variability is shown to be forced mainly by surface wind curl on baroclinic rossby waves annual baroclinic rossby waves cross the basin in less than a few months leaving the upper ocean in a quasi steady sverdrup balance an anomalous cyclonic anticyclonic gyre is generated in winter summer by the anomalous cyclonic anticyclonic wind curl that is associated with the northeasterly southwesterly monsoon in addition surface heat flux acts to enhance the wind generated variability the winter surface cooling warming cools warms the mixed layer especially in the central scs reducing

decadal 1994 2008 change in the carbon isotope ratio in the eastern south pacific ocean we determined the 14 year change in the anthropogenic co2 inventory in the eastern south pacific ocean along the 110 w meridian from 67 s to 21 n using seawater 13c data sets collected in 1994 and 2008 the vertical integral of the 14 year 13c change was assessed in five latitude bands and found to be greatest 14 7 m yr 1 in the subpolar band 38 s 55 s and smallest 3 0 m yr 1 in the tropical band 21 n 18 s the 13c change in each of the latitudinal bands was primarily caused by inputs of anthropogenic co2 via air sea exchange and transport more than 50 of the total anthropogenic co2 was added to the subpolar band via the northward movement of antarctic intermediate water aaiw from the south and the remaining 50 was added via air sea exchange we also calculated the ratio of the temporal change in 13c to the change in dissolved inorganic carbon which is a measure of the efficiency of oceanic uptake of anthropogenic co2 the ratio for aaiw in 1994 0 017 mol kg 1 1 was greater than that in 2008 0 010 mol kg 1 1 based on the change in preformed 13c and dissolved inorganic carbon dic indicating reduced efficiency of co2 uptake by the southern ocean in 2008 relative to that in 1994 aaiw remained at the surface for a shorter period in 2008 relative to 1994 and thus would have taken up less atmospheric co2 prior to subduction the projected reduction in this ratio indicates a weakening of co2 uptake by the southern ocean in the future

the influence of the interdecadal pacific oscillation on temperature and precipitation over the globe the interdecadal pacific oscillation ipo is a 40 60 year quasi oscillation seen mostly in the pacific basin but its impacts on surface temperature t and precipitation p have been found over australia the southwest u s and other regions here a global analysis of ipo s impacts on t and p and its modulation of enso s influence on t and p over the globe is performed using observational and reanalysis data and model simulations since 1920 there are two warm 1924 1944 and 1977 1998 and two cold 1945 1976 and 1999 present ipo phases whose change is associated with abrupt shifts in north pacific sea level pressure slp and contrasting anomaly patterns in t and p and atmospheric circulation over the eastern and western pacific the ipo explains more than half of the interdecadal variations in t and p over many regions such as northeastern australia western canada and northern india significant correlations between the ipo and local p are observed over eastern australia southern africa and the southwest u s the ipo also modulates enso s influence on local t and p over most of these regions t over northern india is positively correlated with nino3 4 enso index during cold ipo phases but the correlation turns negative or insignificant during ipo warm phases over northeastern australia the t versus enso and p versus enso correlations are stronger during the ipo cold phases than during the warm phases the p versus enso correlation over southern africa tends to be negative during ipo warm phases but becomes weaker or insignificant during ipo cold phases the ipo induced p anomalies can be explained by the associated anomaly circulation which is characterized by a high slp center and anti cyclonic flows over the north pacific and negative slp anomalies and increased wind convergence over the indonesia and western pacific region during ipo cold phases these observed influences of the ipo on regional t and p are generally reproduced by an atmospheric model forced by observed sea surface temperatures

early morning irregularities detected with spaceborne gps measurements in the topside ionosphere a multisatellite case study we present observations of the equatorial plasma bubbles epb in the topside ionosphere at early morning hours 05 08 lt in the recovery phase of the 18 19 february 2014 geomagnetic storm this rare type of irregularities was detected in the pacific sector using gps measurements on board several low earth orbit leo satellites we use a multisatellite constellation consisted of the three swarm and one terrasar x satellites that on 19 february flew in the same region and at similar altitudes 500 km the epb occurrence in the leo gps data was observed for several consecutive orbits from 11 ut to 16 17 ut on 19 february 2014 which suggests the following 1 rather long duration hours of favorable conditions for epb generation 2 formation and evolution of epb over wide longitude range of the pacific ocean and 3 possible movement of the epb region in the westward direction with dawn registration of the early morning epb in leo gps data was supported by concurrent in situ swarm and dmsp defense meteorological satellite program and ground based ionosonde and gps measurements leo based gps technique is found to be essential and promising data source to study the topside epb over regions with lack of the ground based facilities in addition we use the prompt penetration model and the thermosphere ionosphere electrodynamics global circulation model tie gcm to identify the possible mechanisms responsible for the observed phenomenon the model simulation results indicate the occurrence of the zone with the enhanced vertical plasma drift 40 45 m s owing to the disturbance dynamo action in the predawn dawn sector during 09 17 ut

generation and life cycle of the dipole in the south china sea summer circulation 1 the south china sea scs summer circulation often has a dipole structure associated with an eastward jet appearing off central vietnam the dipole has an anticyclonic eddy ae south of the jet and a cyclonic eddy ce north of it the life cycle of the dipole structure is analyzed using satellite altimetry data and a reduced gravity model on average the dipole structure begins in june peaks in strength in august or september and disappears in october the dipole evolution lags behind the basin scale wind by about 40 days and 40 days are exactly what it takes for baroclinic planetary waves to cross the southern scs our results show that the vorticity transports from the nonlinear effect of the western boundary currents are crucial for the generation of the dipole structure in addition the strength and direction of the offshore wind jet also play a significant role in determining the magnitudes and the core positions of the two concomitant eddies

pacific east asian teleconnection how does enso affect east asian climate observational evidence is presented to show a teleconnection between the central pacific and east asia during the extreme phases of enso cycles this pacific east asian teleconnection is confined to the lower troposphere the key system that bridges the warm cold events in the eastern pacific and the weak strong east asian winter monsoons is an anomalous lower tropospheric anticyclone cyclone located in the western north pacific the western north pacific wind anomalies develop rapidly in late fall of the year when a strong warm or cold event matures the anomalies persist until the following spring or early summer causing anomalously wet dry conditions along the east asian polar front stretching from southern china northeastward to the east of japan kuroshio extension using atmospheric general circulation and intermediate models the authors show that the anomalous philippine sea anticyclone results from a rossby wave response to suppressed convective heating which is induced by both the in situ ocean surface cooling and the subsidence forced remotely by the central pacific warming the development of the anticyclone is nearly concurrent with the enhancement of the local sea surface cooling both the anticyclone and the cooling region propagate slowly eastward the development and persistence of the teleconnection is primarily attributed to a positive thermodynamic feedback between the anticyclone and the sea surface cooling in the presence of mean northeasterly trades the rapid establishment of the philippine sea wind and sst anomalies implies the occurrence of extratropical tropical interactions through cold surge induced exchanges of surface buoyancy flux the central pacific warming plays an essential role in the development of the western pacific cooling and the wind anomalies by setting up a favorable environment for the anticyclone sst interaction and midlatitude tropical interaction in the western north pacific

the arrival of recently formed labrador sea water in the deep western boundary current at 26 5 n the deep western boundary current dwbc of the north atlantic is a principal conduit between the formation region for labrador sea water lsw and the oceanic interior to the south time series 1985 1997 of hydrographic properties obtained in the dwbc at 26 5 n show that prior to 1994 temperature salinity and transient tracer properties within the lsw density range showed little indication of recently formed parcels properties characteristic of a newer version of lsw cooler fresher and higher tracer concentrations were observed beginning in 1994 and continuing through 1997 longer time series of temperature and salinity developed from a regional data base show both the 1994 and a 1980 1981 event in the abaco region both events are consistent with anomalies in the labrador sea that occurred some 10 years earlier the 10 year transit time from the labrador sea to 26 5 n is less than the 18 year transit time inferred from earlier studies

decadal phase change in large scale sea level and winds in the indo pacific region at the end of the 20th century 1 satellite observations of sea surface height ssh and wind stress for the period of 1993 2006 reveal a near coherent large scale decadal variability in much of the indo pacific region with a phase change at the turn of the 20th century trade wind variations in the tropical pacific and south indian ocean are anti correlated with each other as are ssh differences across these two basins implying anti correlated variation of the subtropical cells in the two oceans decadal changes in large scale ssh in the extra tropics are mostly associated with well defined patterns of wind stress curl indicating a near coherent decadal variation in the strength of subtropical and subpolar gyres together these variations reflect a linkage in the circulation of the pacific and indian oceans via atmospheric and oceanic bridges the phase change in the tropical pacific tends to occur earlier than elsewhere suggesting a potential role of the tropical pacific in regulating decadal variability of the entire region

a 20th century acceleration in global sea level rise 1 multi century sea level records and climate models indicate an acceleration of sea level rise but no 20th century acceleration has previously been detected a reconstruction of global sea level using tide gauge data from 1950 to 2000 indicates a larger rate of rise after 1993 and other periods of rapid sea level rise but no significant acceleration over this period here we extend the reconstruction of global mean sea level back to 1870 and find a sea level rise from january 1870 to december 2004 of 195 mm a 20th century rate of sea level rise of 1 7 0 3 mm yr 1 and a significant acceleration of sea level rise of 0 013 0 006 mm yr 2 this acceleration is an important confirmation of climate change simulations which show an acceleration not previously observed if this acceleration remained constant then the 1990 to 2100 rise would range from 280 to 340 mm consistent with projections in the ipcc tar

large scale variability in the midlatitude subtropical and subpolar north pacific ocean observations and causes abstract altimetric data from the 8 yr topex poseidon t p mission oct 1992 jul 2000 are used to investigate large scale circulation changes in the three current systems of the midlatitude north pacific ocean the north pacific current npc the alaska gyre and the western subarctic gyre wsg to facilitate the understanding of the observed changes a two layer ocean model was adopted that includes first mode baroclinic rossby wave dynamics and barotropic sverdrup dynamics the npc intensified steadily over the t p period from 1992 to 1998 much of this intensification is due to the persistent sea surface height ssh drop on the northern side of the npc a similar ssh trend is also found in the interior of the alaska gyre both of these ssh changes are shown to be the result of surface wind stress curl forcing accumulated along the baroclinic rossby wave characteristics initiated from the eastern boundary in addition to the interior ssh signals the intensity of the alaska gyre is shown to depend

improving the quality of satellite altimetry data over continental shelves 1 satellite altimetry has proven to be a useful tool to study oceanic processes in the deep ocean over continental shelves however the aliasing of unresolved high frequency signals of tidal and wind induced origin is the source of long wavelength errors that corrupt altimetry measurements and limit their use in shallow waters in 2005 ssalto duacs performed a complete reanalysis of altimeter data to accommodate the latest tidal model got2000 and a correction for the aliased high frequency signals using a hydrodynamic model mog2d g this paper examines the quality and the performance of the newly released altimetry data over the northwest european shelf this region is known for complex tides and for frequent storm surges the newly corrected maps of sea level anomalies were compared with a previous altimetry product residual tidal aliasing was analyzed and the impact of mog2d g and got2000 models was assessed altimeter records were compared with tide gauge measurements this research showed a significant reduction in the contamination of data by high frequency aliasing achieved through the use of the aforementioned models however aliased shallow water tidal constituents pose a serious problem and it is obvious that future tidal corrections should feature local tides nonaliased physical sea level variability was also studied focusing on interannual seasonal and intra annual periods from 20 days to 1 year modes the magnitudes and the contributions of each mode to the total variance were estimated it was demonstrated that the newly corrected data can successfully be used to study the variability of sea level over continental shelves

reconstructing sea level using cyclostationary empirical orthogonal functions 1 cyclostationary empirical orthogonal functions derived from satellite altimetry are combined with historical sea level measurements from tide gauges to reconstruct sea level fields from 1950 through 2009 previous sea level reconstructions have utilized empirical orthogonal functions as basis functions but by using cyclostationary empirical orthogonal functions and by addressing other aspects of the reconstruction procedure an alternative sea level reconstruction can be computed the procedure introduced here is capable of capturing the annual cycle and el nino southern oscillation enso signals back to 1950 with correlations between the reconstructed enso signal and common enso indices found to be over 0 9 the regional trends computed from the new reconstruction show good agreement with the trends obtained from the satellite altimetry but some discrepancies are seen when comparing with previous sea level reconstructions over longer time periods the computed rate of global mean sea level rise from the reconstructed time series is 1 97 mm yr from 1950 to 2009 and 3 22 mm yr from 1993 to 2009

thermal variations in the south china sea associated with the eastern and central pacific el nino events and their mechanisms in this study we investigate the interannual variability of the sea surface temperature sst in the south china sea scs associated with two types of el nino namely the eastern pacific ep el nino and the central pacific cp el nino first double warm peaks can occur during both types of el nino events in the scs however the strong warm basin mode can only develop in the ep el nino while the warm semibasin mode exists during the cp el nino associated with an anomalous positive negative net surface heat flux in the ep cp el nino along with a shallower thermocline with weaker stronger northeasterly wind anomalies the sst anomalies become warmer cooler in the developing autumn over the background of cooling sst in autumn of cp el nino therefore only a weak warming can occur in the subsequent years which is limited in the western boundary area under the forcing of warm ocean advection second the sst oscillation periods are different in these two types of el nino the sst evolution in the ep el nino is negative positive with a quasi biennial oscillation but that in the cp el nino is positive negative positive negative with an annual oscillation it seems that the double cooling in the cp el nino is phase locked to the late autumn season

regime shift of the south china sea sst in the late 1990s decadal variability of the south china sea scs sea surface temperature sst during 1982 2014 is investigated using observations and ocean reanalysis datasets the scs sst shows an abrupt transition from a cold to warm regime in the late 1990s based on the long term sst variability two epochs are defined 1982 1996 and 2000 2014 as cold and warm regimes respectively spanning on either side of the 1997 1999 scs warming despite the occurrence of strong el nino induced warming events the sst anomalies tend to be negative in the cold regime conversely during the warm regime the positive sst anomalies have dominated over the la nina driven cooling events the cold warm sst regime is marked by net heat gain loss by the scs the long term variations of net surface heat flux are mainly driven by the latent heat flux anomalies while the short wave flux plays a secondary role low frequency variability of the south china sea throughflow scstf appears to be closely related to the scs sst regime shift the scstf shows reversing trends during the cold and warm epochs the weakened scstf in the warm regime has promoted the scs warming by limiting the outward flow of warm water from the scs meanwhile enhanced scstf during the cold regime acts as a cooling mechanism and lead to persistent negative sst anomalies the change in trend of the scstf and sst regime shift coincides with the switching of pacific decadal oscillation from a warm to cold phase in the late 1990s

decadal shift in el nino influences on indo western pacific and east asian climate in the 1970s abstract el nino s influence on the subtropical northwest nw pacific climate increased after the climate regime shift of the 1970s this is manifested in well organized atmospheric anomalies of suppressed convection and a surface anticyclone during the summer june august of the el nino decay year jja 1 a season when equatorial pacific sea surface temperature sst anomalies have dissipated in situ observations and ocean atmospheric reanalyses are used to investigate mechanisms for the interdecadal change during jja 1 the influence of the el nino southern oscillation enso on the nw pacific is indirect being mediated by sst conditions over the tropical indian ocean tio the results here show that interdecadal change in this influence is due to changes in the tio response to enso during the postregime shift epoch the el nino teleconnection excites downwelling rossby waves in the south tio by anticyclonic wind curls these rossby waves propagate slowly westward causing persistent sst warmi

does carbon 13 track anthropogenic co2 in the southern ocean a multiparametric linear regression technique was used for waters in the southern ocean to estimate the change in both 13 c dic 13 c dic and dissolved inorganic carbon dic dic between 1978 and 1998 due to the accumulation of anthropogenic co 2 the observed decrease in 13 c dic at the surface the suess effect was 0 015 0 003 yr 1 in the sub antarctic zone and 0 005 0 003 yr 1 in the antarctic zone similar to values reported for the southern indian ocean gruber et al 1999 sonnerup et al 2000 to compare the 13 c dic with adic we used the ratio of these two anomalies rc 13 c dic dic mol kg 1 1 along the section arc ranged from 0 015 0 005 at 42 s to 0 007 0 005 mol kg 1 1 at 54 s the spatial variability in arc in the southern ocean reflects different timescales for processes controlling the uptake of 13 c from those controlling the uptake of 12 c and indicates that 13 c dic decouples from adic poleward of the sub antarctic zone the variations of arc along the section suggest that the 13 c dic anomaly is not a good predictor of the anthropogenic co 2 inventory in the southern ocean some methods for determining anthropogenic co 2 uptake both on the global and regional scale assume the penetration depths of 13 c dic to be the same as adic which implies a constant value for arc in the ocean at 0 016 mol kg 1 1 heimann and maier reimer 1996 ortiz et al 2000 bauch et al 2000 the use of a constant arc and the observed 13 c dic to estimate anthropogenic co 2 could lead to an underestimate in the inventory of anthropogenic co 2 for the southern ocean by 50

carbon isotope records from extant caribbean and south pacific sponges evolution of δ13c in surface water dic stable isotope records of demosponges from the caribbean and coral sea are described for the purpose of studying the influence of fossil fuel co2 on the carbon isotopic composition of dissolved inorganic carbon dic in surface water the slow growing sponges precipitate calcium carbonate in isotopic equilibrium with ambient sea water and are used to detect changes in 13cdic from pre industrial times early 19th century to the present we observed similar shapes and ranges in 13c curves measured on caribbean specimens collected from water depths of 25 84 and 91 m as well as a specimen collected in shallow waters off new caledonia the records reveal a highly significant correlation with atmospheric 13cco2 13cdic values for caribbean and coral sea surface waters were calculated using the 13c sponge records while 13c of atmospheric co2 decreased by about 1 4 from the early 19th century to 1990 13cdic of caribbean and coral sea surface waters decreased by 0 9 0 2 and 0 7 0 3 respectively no isotopic equilibrium between surface water dic and atmospheric co2 was observed either during the pre industrial steady state or during the last 100 years the lower amount of depletion in the surface water 13cdic with respect to the atmospheric anthropogenic signal is explained by the dilution of the surface waters by biologically altered subsurface water dic the lower 13c decrease in the coral sea points to a stronger influence of the subsurface water source compared to the caribbean

anthropogenic co2 accumulation rates in the north atlantic ocean from changes in the 13c 12c of dissolved inorganic carbon 1 the anthropogenic co2 accumulation rate for the north atlantic ocean was estimated on the basis of the decrease in the 13c of the dissolved inorganic carbon measured between cruises in 1981 transient tracers in the north atlantic 1993 oaces and 2003 repeat hydrography a mean depth integrated 13c change of 15 0 3 8 m yr 1 was estimated by applying a multiple linear regression approach to determine the anthropogenic 13c decrease at 22 stations where 13c depth profiles were compared the largest and deepest anthropogenic 13c decreases occurred in the subpolar ocean and in contrast the smallest and shallowest decreases occurred in the tropical ocean a mean anthropogenic co2 accumulation rate of 0 63 0 16 mol c m 2 yr 1 0 32 0 08 pg c yr 1 in the north atlantic ocean over the last 20 years was determined from the mean depth integrated 13c change and a ratio of anthropogenic 13c to dic change of 0 024 mol kg 1 1 only half of the accumulated anthropogenic co2 in the north atlantic during the last 20 years was the result of air sea co2 uptake based on a comparison of the air sea 13co2 flux to the dic13 inventory change with the other half likely a result of northward advective transport

kuroshio intrusion into the south china sea a review the kuroshio carrying the northwestern pacific water intrudes into the south china sea scs through the luzon strait significantly affecting the temperature salinity circulation and eddy generation in the scs thus the kuroshio intrusion makes important contributions to the momentum heat and salt budgets in the scs in the past decades much work has been done on the kuroshio intrusion this paper reviews past efforts and summarizes our current understanding of the kuroshio intruding processes from observational evidence laboratory results theoretical analyses and a range of numerical model simulations in addition discrepancies between results simulated by models as well as those between simulations and observations are presented specifically this paper addresses the following topics 1 different types of the kuroshio intrusion into the scs and their identification 2 vertical structure of the kuroshio in the luzon strait 3 an overview of the luzon strait transport resulting from observations and numerical model simulations 4 seasonal and interannual variations of the kuroshio intrusion as well as eddy generation due to the kuroshio path variation and 5 dynamical mechanisms e g wind forcing interbasin pressure gradient beta effect and hysteresis potential vorticity eddy activity controlling the kuroshio intrusion into the scs finally several future research topics for gaining a better understanding of the kuroshio intruding processes are suggested c 2014 the authors published by elsevier ltd

the distribution of bomb radiocarbon in the ocean water column inventories are calculated for bomb radiocarbon at all the stations occupied during the geosecs and norpax expeditions and for the available tto stations the pattern of global inventories obtained in this way suggests that a sizable portion of the bomb radiocarbon that entered the antarctic the northern pacific and the tropical ocean has been transported to the adjacent temperate zones a strategy for utilizing these inventory anomalies as constraints on global ocean circulation models is presented essential to this strategy are the improvement of our knowledge of the pattern of wind speed over the ocean the establishment of the wind speed dependence of the rate of gas exchange between the atmosphere and sea and the continued mapping of the distribution of bomb produced radiocarbon in the sea

summer upwelling in the south china sea and its role in regional climate variations seasonal and interannual variations of summer upwelling off the south vietnam coast and the offshore spread of cold water are investigated using a suite of new satellite measurements in summer as the southwesterly winds impinge on annam cordillera a north south running mountain range on the east coast of indochina a strong wind jet occurs at its southern tip offshore east of saigon resulting in strong wind curls that are important for ocean upwelling off the coast in july and august an anticyclonic ocean eddy develops to the southeast advecting the cold coastal water offshore into the open south china sea scs the center of this cold filament is located consistently north of the wind speed maximum indicating that open ocean upwelling helps to cool the ocean surface corroborating evidence for the cold filament is found in ocean color observations that reveal a collocated tongue of high chlorophyll concentration the development of this cold filament disrupts the summer warming of the scs and causes a pronounced semiannual cycle in sst moreover the cold filament is an important player in interannual variability in the summer scs in 1998 the cold filament and mid summer cooling never took place giving rise to a strong basin wide surface warming interannual sst variance has a local maximum over the climatological cold filament and is much greater than the variance over the adjacent indian and western pacific oceans a cold filament index is constructed which displays significant lagged correlation with sst in the eastern equatorial pacific and indian oceans indicative of a teleconnection from el nino

the indian ocean 13c suess effect the 13c of dissolved inorganic carbon dic decrease the 13c suess effect in the indian ocean was calculated using a multiparameter linear regression comparison of the 1978 geochemical ocean sections study and 1995 world ocean circulation experiment 13c of dic hydrographic and nutrient data the surface ocean 13c decrease rate along 80 and 115 e ranged from approximately 0 1 decade 1 at 55 s to a maximum of approximately 0 18 decade 1 at 35 s and decreased northward to around 0 13 decade 1 at the equator using a global extrapolation based on ocean model results bacastow et al 1996 and previous 13c changes calculated from 1970 to 1993 station reoccupations in the pacific ocean and based on preformed 13c versus chlorofluorocarbon age trends in the indian pacific and atlantic oceans sonnerup et al 1999 an ocean wide average surface ocean 13c rate of change of 0 15 to 0 17 decade 1 was estimated the average depth integrated 13c change rate between 1978 and 1995 along 80 and 115 e was 6 9 0 5 m yr 1 from 58 s to 5 n

interannual modulation of the pacific decadal oscillation pdo on the low latitude western north pacific to investigate the interannual variability in the northwestern pacific an empirical mode decomposition emd was applied to 17 year absolute dynamic topography adt data west of luzon island the philippines the mean sea surface height in this area is an appropriate index for the kuroshio intrusion into the south china sea scs significant interannual fluctuations were extracted by the emd the interannual variability was strongly correlated with the pacific decadal oscillation pdo index but not the el nino southern oscillation enso this indicated the potential impact of the pdo on the circulation in the area in the warm phase of the pdo positive index a southerly anomalous wind off the philippines causes a northward shift of the north equatorial current bifurcation latitude necbl this leads to a weakened kuroshio off luzon favoring kuroshio intrusion into the scs the northward migration of the necbl also results in a weakened kuroshio off southeast taiwan and a larger kuroshio transport off northeast taiwan the abundant westward propagating eddies impinging on the kuroshio in the subtropical countercurrent region increases this transport although the enso has little effect on monsoonal winds during the warm pdo phase it has a strong impact on the monsoon and meridional migration of the necbl during the cold phase of the pdo therefore necbl variations only show a close correspondence with the enso during the cold pdo phase because the influence of the enso is not stationary the impact of the pdo should be taken into account when examining interannual variability in the low latitude western north pacific

interdecadal variability of the eastward current in the south china sea associated with the summer asian monsoon abstract based on the simple ocean data assimilation soda dataset and three types of sverdrup streamfunction an interdecadal variability of the eastward current in the middle south china sea scs during summer is identified both the pattern and strength of the summer asian monsoon wind stress curl over the scs contribute to the interdecadal variability of this current from 1960 to 1979 the monsoon intensified and the zero wind stress curl line shifted southward both the core of positive wind stress curl in the northern scs and the negative curl in the southern scs moved southward and thus induced a southward shift of both the southern anticyclonic and northern cyclonic gyres resulting in a southward displacement of the eastward current associated with these two gyres in the meantime the southern northern scs anticyclonic cyclonic ocean gyre weakened strengthened and therefore also induced the southward shift of the eastward current near the intergyre boundary in contrast the eastward cu

different responses of sea surface temperature in the south china sea to various el nino events during boreal autumn abstractthis study investigates variations of sea surface temperature sst anomalies in the south china sea scs during developing autumn of various el nino events the warm sst anomalies are observed in the scs for canonical el nino and el nino modoki i whereas the cold sst anomalies are found for el nino modoki ii the ocean heat budget analyses show that the latent heat flux change induced by various types of el nino events is a major contributor to the scs sst variations an anomalous anticyclone resides near the philippine sea for canonical el nino and el nino modoki i which induces the southerly wind anomalies over the scs and thus weakens the climatological northeasterly in boreal autumn the weakened surface wind speed reduces heat loss from the ocean leading to a warmer state in the scs however for el nino modoki ii the anomalous anticyclone shifts westward to the west of the scs and thus the northeasterly wind anomalies appear in the scs the northeasterly anomalies enhance the climatol

miocene ocean circulation inferred from marine carbon cycle modeling combined with benthic isotope records 1 in a modeling sensitivity study we investigate the evolution of the ocean circulation and of marine carbon isotope 13c records during the miocene about 23 5 million years ago for this purpose we ran an ocean circulation carbon cycle model of intermediate complexity large scale geostrophic hamburg ocean carbon cycle model version 2s exploring various seaway configurations our investigations confirm that the central american seaway played a decisive role in the history of the miocene ocean circulation in simulations with a deep central american seaway depth range 1 3 km typical for the early to middle miocene deep water production in the north atlantic is absent or weak while the meridional overturning circulation is dominated by water mass formation in the southern ocean deep water formation in the north atlantic begins when the central american seaway shoals to a few hundreds of meters which is typical for the late miocene our results do not support ideas that the mid miocene closing of the eastern tethys contributed to antarctic glaciation on the other hand we find some water exchange between the indian ocean and the atlantic via the eastern tethys during the early miocene our model results for the atlantic meridional overturning circulation and for atlantic 13c during the late miocene are largely independent from depth variations of the greenland scotland ridge to a large extent the evolution of miocene deep sea 13c records can be explained with large scale ocean circulation changes our model data comparison for the middle and early miocene suggests that during the early neogene the seaway effect on benthic 13c may have been superimposed by further factors such as climate regime shifts and or terrestrial carbon cycle changes

imprint of the pacific decadal oscillation on the south china sea throughflow variability abstractanalysis of the 62 yr hindcast outputs from an eddy resolving ocean general circulation model reveals a prominent decadal variability in the upper layer 0 745 m luzon strait transport lst a key component of the south china sea throughflow this variability is in phase with the basin scale wind stress anomalies associated with the pacific decadal oscillation pdo a composite analysis shows that during the positive phase of the pdo the aleutian low and its related positive wind stress curl anomalies intrude southward reducing the trade winds and enhancing the westerly wind anomalies in the tropical north pacific in response the north equatorial current bifurcation shifts northward resulting in a weaker kuroshio east of luzon and consequently a stronger south china sea throughflow in the upper 745 m

modes of diagenesis responsible for observed succession of potash evaporites in the salado formation delaware basin new mexico abstract clays are a prevalent constituent of the mcnutt potash member of the upper salado formation permian new mexico the mode of clay distribution is varied and is an important indicator of fluid movement clays in the study area occur as thick clay seams up to 4 cm disseminated deposits and as linings on crystal contacts of evaporite minerals these different occurrences represent different conditions during evaporite deposition 1 thick clay seams represent major incursions of fresh seawater diluting the brine in the shallow delaware basin 2 disseminated deposits represent undisturbed portions of primary evaporite deposition and 3 clay linings on langbeinite and sylvite depict percolation of solutions that dissolve preexisting minerals resulting in deposition of clays during downward migration of the solution front although the clay chemistry varies little the clay mineralogy differs with respect to its associated evaporite mineralogy low charge corrensite is associated with potassium deficient salts like halite anhydrite and polyhalite high charge corrensite is associated with potassium rich salts like sylvite and langbeinite three modes of evaporite diagenesis are invoked to explain the major evaporite mineral assemblages in the mcnutt potash member syndepositional alteration best explains the occurrence of polyhalite burial diagenesis fits well in explaining the minor amounts of kainite replacing langbeinite in or near clay rich areas retrograde diagenesis seems to be the dominant mechanism responsible for formation of the potash bitter salts the retrograde process involves percolation of fresh seawater into poorly crystallized strata causing the replacement of primary salts like kainite kieserite and carnallite with secondary salts like langbeinite sylvite and loewite

impact of the indian ocean sst basin mode on the asian summer monsoon 1 following an el nino event a basin wide warming takes place over the tropical indian ocean peaks in late boreal winter and early spring and persists through boreal summer our observational analysis suggests that this indian ocean warming induces robust climatic anomalies in the summer indo west pacific region prolonging the el nino s influence after tropical east pacific sea surface temperature has returned to normal in response to the indian ocean warming precipitation increases over most of the basin forcing a matsuno gill pattern in the upper troposphere with a strengthened south asian high near the ground the southwest monsoon intensifies over the arabian sea and weakens over the south china and philippine seas an anomalous anticyclonic circulation forms over the subtropical northwest pacific collocated with negative precipitation anomalies all these anomaly patterns are reproduced in a coupled model simulation initialized with a warming in the tropical indian ocean mixed layer indicating that the indian ocean warming is not just a passive response to el nino but important for summer climate variability in the indo west pacific region the implications for seasonal prediction are discussed