basin development and syntectonic sedimentation associated with kinematically coupled strike slip and detachment faulting southern nevada a previously unrecognized 12 10 ma clastic sequence is distributed widely south of the las vegas valley shear zone and north of lake mead in southern nevada structural and stratigraphic evidence from these sedimentary and associated volcanic rocks suggests that basin development was kinematically related to movement along the las vegas valley shear zone major movement along the nearby saddle island detachment also occurred within this time interval we suggest that spatially and temporally related basin development sedimentation and stratal tilting reflect kinematically coupled movement along a combined las vegas valley shear zone saddle island detachment fault system

observations of the kuroshio s barotropic and baroclinic responses to basin wide wind forcing 1 observations show that the kuroshio in the east china sea ecs kuroshio responds to the large scale wind stress curl field at two time scales it is argued that these two responses are related to barotropic and baroclinic modes that reach the ecs via different waveguides variability in the ecs kuroshio is assessed by comparing satellite altimetry historical hydrography and the pacific decadal oscillation pdo index with the latter used as a proxy for the large scale wind stress curl forcing sea level difference across the ecs kuroshio is positively correlated with pdo at zero lag and negatively correlated at 7 year lag in contrast pycnocline steepness and pdo are uncorrelated at zero lag and negatively correlated at 7 year lag these signals in the ecs kuroshio considered together with wind stress curl anomalies in the open ocean are consistent with a barotropic response to the wind at zero lag the barotropic response is likely forced in the central north pacific by wind stress curl anomalies of opposite sign one of which is centered at ecs latitudes 27 n while the other sits further north this suggests that in general the absolute transport at a given latitude is not simply that predicted by the sverdrup balance along the latitude this is a consequence of waveguides that can steer the barotropic mode across latitude lines in contrast the signals that lag pdo by 7 years are consistent with a baroclinic mode which represents the ocean s time integrated response to the wind stress curl along a single latitude band between 24 n and 27 n

anatomy of north pacific decadal variability abstract a systematic analysis of north pacific decadal variability in a full physics coupled ocean atmosphere model is executed the model is an updated and improved version of the coupled model studied by latif and barnett evidence is sought for determining the details of the mechanism responsible for the enhanced variance of some variables at 20 30 yr timescales the possible mechanisms include a midlatitude gyre ocean atmosphere feedback loop stochastic forcing remote forcing or sampling error decadal variability in the model is expressed most prominently in anomalies of upper ocean streamfunction sea surface temperature sst and latent surface heat flux in the kuroshio oyashio extension koe region off japan the decadal signal off japan is initiated by changes in strength and position of the aleutian low the atmospheric perturbations excite sst anomalies in the central and eastern north pacific with opposing signs and canonical structure the atmospheric perturbations also change the ekm

interdecadal variability of the sea surface height around japan 1 the variability of the sea surface height ssh around japan during 1960 2002 was investigated using an ocean general circulation model the first eof mode of the simulated ssh change has bidecadal variability and exhibits simultaneous variations around japan that are in good agreement with the observed sea level changes along the japanese coast the variability is caused primarily by the meridional shift of the boundary between the subtropical and subpolar gyres due to shifting of the westerlies over the central north pacific the second mode of ssh change indicates a north south dipole structure around japan that results from a change in the strength of the subtropical gyre due to a change in the magnitude of the westerlies the rising descending trend of the sea level observed in the western eastern part of japan in the past 40 years is determined by the increasing trend of the westerlies

midlatitude atmosphere ocean interaction during el nino part i the north pacific ocean abstract atmosphere ocean experiments are experiments are used to investigate the formation of sea surface temperature sst anomalies in the north pacific ocean during fall and winter of the el nino year experiments in which the ncar community climate model ccm surface fields am used to force a mixed layer ocean model in the north pacific no air sea feedback are compared to simulations in which the ccm and north pacific ocean model are coupled anomalies in the atmosphere and the north pacific ocean during el nino are obtained from the difference between simulations with and without prescribed warm sst anomalies in the tropical pacific in both the forced and coupled experiments the anomaly pattern resembles a composite of the actual sst anomaly field during el nino warm ssts develop along the cost of north america and cold ssts form in the central pacific in the coupled simulations air sea interaction results in a 25 to 50 reduction in the magnitude of the sst and mixed layer depth anomalies

rock types and permeability prediction from dipmeter and image logs shuaiba reservoir aptian abu dhabi the shuaiba formation is a complex carbonate reservoir characterized by small scale geological heterogeneity primarily related to rudist macrofauna the textural heterogeneity corresponds to extreme permeability variation that is the controlling factor in reservoir production because of the large vertical resolution contrast between cores actual scale and conventional logs averaged responses over a few feet extrapolation of small scale heterogeneity into uncored wells using a traditional approach is unreliable high resolution log data like dipmeters and image logs are required to characterize small scale heterogeneity that is essential to a good three dimensional 3 d geological model that predicts true reservoir behavior our study illustrates an approach to improve the reservoir characterization of the shuaiba by quantifying small scale heterogeneity using dipmeter and image logs a methodology is proposed to use the existing high resolution high resolution dipmeter tool hdt stratigraphic high resolution dipmeter tool shdt and formation microscanner fms and conventional log data to characterize and extrapolate geological heterogeneity texture and neural network analyses derived from microresistivity variations and a multiregression approach have been used in two wells to demonstrate the methodology both rock types and permeability are estimated for extrapolation into uncored wells although differences between the conductivity of conductive and resistive areas when normalized for background conductivity are an indirect measure of permeability for hdt and shdt the connectivity coefficient of conductive anomalies derived from textural analysis is related to permeability in the case of fms reservoir rock types rrt obtained from the methodology correlate well with rrts derived from the integration of core special core analysis scal and conventional log data in two test wells permeability estimations including small scale extreme variations from less than 1 md in tight mudstones to greater than 1 d in caprinid rudstones are in good agreement with the core plug permeability measurements after a simple calibration in one example permeability trends in rudist rrts which are not discernible using core plugs and minipermeameter data are clearly resolved using shdt data the degree of correlation between estimated and core permeabilities is greater with increased vertical resolution of the tool hdt lowest fms highest distinct rrts resulting from small scale geological heterogeneity can be classified and permeability can be estimated with a high degree of confidence providing a better pathway of extrapolating from core data to conventional logs for 3 d modeling the methodology has potential application to other carbonate and siliciclastic reservoirs with appropriate calibration and scaling underused hdt shdt fms and fullbore formation microimager fmi databases are available in many other areas that could be analyzed an order of magnitude improvement in the ability to characterize small scale heterogeneity has significant implications for future coring logging programs and reservoir characterization efforts duffy russell is a senior carbonate geologist at saudi aramco in the reservoir characterization department southern fields characterization division he received b s and m s degrees in geology from north carolina state university in 1976 and duke university in 1979 and a ph d in geology from the university of aberdeen in 2001 he started his career as a geophysicist with amoco production company in 1979 and has worked nearly 21 years as a geologist for mobil oil corporation and exxonmobil specializing in carbonate reservoir characterization mahmoud akbar is a principal geologist for schlumberger working iran qatar the united arab emirates oman and yemen he started his professional career with schlumberger wireline and testing in 1985 in pakistan he received b sc 1983 and m sc 1985 degrees in applied geology from the university of punjab pakistan he has carried out research in the lower himalayas on factors controlling fractures and their effect on rock strength badarinadh vissapragada is a senior petrophysicist with schlumberger data and consulting services abu dhabi united arab emirates he did his postgraduate study in geophysics at andhra university waltair india he has more than 19 years of petrophysics experience in india and middle east reservoirs from fieldwide petrophysical studies and reservoir characterization his special interests are reservoir rock typing permeability and fracture detection gordon walkden is head of the department of geology and petroleum geology at the university of aberdeen scotland after receiving a degree from quintin school in london he obtained his ph d in carbonate sedimentology from manchester university united kingdom in 1970 gordon was appointed senior lecturer in 1988 and became department head in 1993 he has extensive field experience and supervision of research projects in britain europe north america and the middle east

response of the separated western boundary current to harmonic and stochastic wind stress variations in a 1 5 layer ocean model abstract a time dependent version of the parsons model geostrophic 1 5 layer model of the ventilated thermocline has been developed to investigate the response of the midlatitude ocean to wind stress variations in a simple configuration in this model the total amount of water is kept constant and the eastern boundary thermocline depth can vary in time so as to maintain mass balance here basin modes are not investigated in contrast to many recent studies but the emphasis is on the line where the motionless second layer outcrops which represents the separated western boundary current it is shown that the position of this line only depends on the wind stress the earth rotation and the thermocline interior solution the position is not influenced by the parameterization of the dissipative processes this generalizes previous results established in the stationary case the displacement of the outcrop line in the case of harmonic or stochastic wind stress variations is computed numerically showing

ventilation of the subtropical north pacific abstract the ventilation of the subtropical north pacific is studied using a simple analytical model the model is forced by winter mixed layer density and depth calculated from the levitus climatology and wind stress curl from the hellerman and rosenstein wind stress data the wind driven gyre in the north pacific is shallow no more than 1 4 km the gross feature of the subduction rate is very similar to the results by huang and qiu based on data analysis of the levitus climatology with a total ventilation rate of 31 3 sv sv 106 m3 s 1 including 20 8 sv due to the vertical pumping and 10 5 sv due to lateral induction the age of water within the ventilated thermocline is relatively young it is no more than 10 years old except near the southeast corner of the basin the young age indicates a fast communication between the atmosphere and the upper ocean on a timescale of less than 10 years the vertical mass partition is slightly different from the results based on analysing climatology by huang a

investigating the local atmospheric response to a realistic shift in the oyashio sea surface temperature front abstractthe local atmospheric response to a realistic shift of the oyashio extension sst front in the western north pacific is analyzed using a high resolution hr 0 25 version of the global community atmosphere model version 5 cam5 a northward shift in the sst front causes an atmospheric response consisting of a weak surface wind anomaly but a strong vertical circulation extending throughout the troposphere in the lower troposphere most of the sst anomaly induced diabatic heating is balanced by poleward transient eddy heat and moisture fluxes collectively this response differs from the circulation suggested by linear dynamics where extratropical sst forcing produces shallow anomalous heating balanced by strong equatorward cold air advection driven by an anomalous stationary surface low to the east this latter response however is obtained by repeating the same experiment except using a relatively low resolution lr 1 version of cam5 comparison to observations suggests that the hr respo

sea surface temperature anomalies planetary waves and air sea feedback in the middle latitudes the mechanisms that contribute to the generation and damping of large scale mid latitude sea surface temperature sst anomalies are discussed the sst anomalies reflect primarily the response of the upper ocean to the changes in air sea fluxes that are associated with daily weather fluctuations heat flux forcing is dominant in the lower middle latitudes while wind driven entrainment may be most effective in the high latitudes advection by anomalous ekman current is generally less important and ekman pumping is negligible the sst anomalies decay in part because of entrainment effects associated with mixed layer deepening and oceanic mixing and in part because of heat exchanges with the atmosphere the three approaches commonly used to model the evolution of sst anomalies are reviewed case studies based on monthly or seasonal anomaly maps of the large scale sst and atmospheric anomalies numerical simulations with one dimensional mixed layer models and stochastic forcing models we stress the similarities in the different approaches and discuss their main advantages and limitations the response of the atmosphere to mid latitude sst anomalies is considered first we discuss the poorly known relationship between sst anomalies and diabatic heating using a crude assumption for the air sea coupling we consider a two layer quasi geostrophic channel model and discuss the stationary wave response to sst anomaly forcing and the resulting air sea feedback it is found that the back interaction of the sst anomalies onto the atmosphere causes a weak sst anomaly damping at large scales and a strong one at small scales the air sea coupling should also act as an eastward propagator for the sst anomalies the response of more realistic linear wave models to prescribed diabatic heating is then reviewed and it is suggested that realistic mid latitude sst anomalies have a weak influence on the atmospheric circulation corresponding to changes in the geopotential height of 10 30 m at most this order of magnitude is consistent with the results of general circulation model experiments and with the limited climate predictability associated with mid latitude sst anomalies

interannual variability in the mid and low latitude western north pacific abstract twenty two years 1967 88 of hydrographic data collected by the japan meteorological agency along the 137 e meridian and surface wind data compiled by florida state university fsu were analyzed to study the interannual variability in the western north pacific in the midlatitude region north of 22 n the dominant signal in the dynamic height field was the interannual path variations of the kuroshio whereas the eastward transport of the kuroshio itself had no significant changes between the straight path and meander path years the net transport of the kuroshio system including recirculations showed a 30 increase during the meander path years in the straight path years when the net transport was small the kuroshio tended to take a straight path with a strong recirculation developed to the south the interannual path variations of the kuroshio strongly influenced the water mass movement in the midlatitudes during the kuroshio meander years we found that a significant portion of the north p

generation mechanism of quasidecadal variability of upper ocean heat content in the equatorial pacific ocean 1 we investigate the relationship between oceanic and atmospheric anomaly fields in the tropical pacific on the quasidecadal qd 10 to 18 years scale is explored it is suggested that the anomalous wind stress curl in the tropical south pacific can generate the equatorial upper ocean heat content ohc anomalies on the qd scale via the sverdrup transport resembling that of the recharge discharge oscillator model for the dynamics of el nino southern oscillation enso the results also show that the wind stress curl anomalies in the tropical south pacific are accompanied by enso like qd scale anomaly patterns of the sea level pressure and sea surface temperature furthermore the results indicate that the equatorial qd scale ohc anomalies can also be generated by the enso like propagations of the ohc anomalies in the tropical north and south pacific this study presents a systematic linkage between the enso like qd scale ohc propagation in the tropical north and south pacific the sverdrup transport variation in the tropical south pacific and the enso like qd scale sst and slp anomalies in the tropical pacific

decadal changes in the north pacific oceanic frontal zones as revealed in ship and satellite observations 1 influence of decadal climate changes upon the north pacific subarctic and subtropical oceanic frontal zones np safz and np stfz respectively is documented both satellite and ship measured sea surface temperature sst data reveal the strong confinement of wintertime decadal sst anomalies to those frontal zones the satellite data indicate that the wintertime np safz tended to be narrow and shift northward under the weakened surface westerlies during a warm event in the early 1990s the opposite was the case under the enhanced westerlies during a cool event in the mid 1980s decadal scale modulations in the frontal intensity are also evident in the satellite data a diagnosis based on a simple linearized mixed layer model suggests that the observed anomalous frontal intensity was contributed by the sign reversal of anomalous wind stress curl through the ekman processes and by an anomaly dipole of the net heat flux around the safz these decadal scale modulations in the np safz and their relationships with decadal fluctuations in the local surface westerlies are confirmed in the ship measured data over the 4 recent decades it is found that the safz happens to be a region where the decadal variability in the surface westerlies are unlikely to be masked by the higher frequency fluctuations as it almost coincides with the ridge trough line of the remote atmospheric response to the el nino southern oscillation

interannual to interdecadal variability in the japan sea based on a new gridded upper water temperature dataset a new gridded water temperature dataset of upper 400 m depths 0 50 100 200 300 and 400 m for the japan sea or east sea is produced by using an optimal interpolation technique from 1930 to 1996 based on oceanographic observations collected in the world ocean database 1998 the temperature data are analyzed by a complex empirical orthogonal function ceof with six levels combined using the data for a period from 1957 to 1996 during which most of gridded data are available before calculating the ceofs low pass or highpass filters cutoff period at 7 yr are applied to separate interannual and decadal temperature changes respectively one interannual and two decadal ceof modes are identified the interannual first ceof mode is characterized by the energetic variability around and south of the subpolar front in the western japan sea accompanied by northward and northeastward phase propagations emanating from the tsushima strait the decadal first ceof mode exhibits a broad structure prevailing over the whole japan sea but large amplitudes are trapped by the subpolar front with 608 908 phase lags between the northeastern and southwestern japan sea the decadal second ceof mode has a localized structure with strong correlations in the yamato basin the relation between the atmosphere and ocean is analyzed by a correlation analysis of wintertime sea level pressures slps onto the temporal coefficients of the ceof modes the interannual first ceof mode is accompanied by the slp anomalies over the western north pacific ocean with steep slp gradients over the japan sea suggesting that this mode is forced by local wind anomalies associated with the slp changes over the western north pacific the decadal first ceof mode is likely to be caused by changes of the east asian winter monsoon due to the slp variability of the northern part of the siberian high which is closely associated with the decadal fluctuations of the arctic oscillation and the north atlantic oscillation the second decadal ceof mode is accompanied by high slp correlations over the central north pacific associated with strength changes of aleutian lows suggestive of remote forcing from the central north pacific

role of the gulf stream and kuroshio oyashio systems in large scale atmosphere ocean interaction a review abstract ocean atmosphere interaction over the northern hemisphere western boundary current wbc regions i e the gulf stream kuroshio oyashio and their extensions is reviewed with an emphasis on their role in basin scale climate variability sst anomalies exhibit considerable variance on interannual to decadal time scales in these regions low frequency sst variability is primarily driven by basin scale wind stress curl variability via the oceanic rossby wave adjustment of the gyre scale circulation that modulates the latitude and strength of the wbc related oceanic fronts rectification of the variability by mesoscale eddies reemergence of the anomalies from the preceding winter and tropical remote forcing also play important roles in driving and maintaining the low frequency variability in these regions in the gulf stream region interaction with the deep western boundary current also likely influences the low frequency variability surface heat fluxes damp the low frequency sst anomalies ove

wind driven shifts in the latitude of the kuroshio oyashio extension and generation of sst anomalies on decadal timescales abstract the causes of decadal variations of north pacific sea surface temperatures ssts are examined using a hindcast performed with an ocean general circulation model thermodynamically coupled to an atmospheric mixed layer model ogcm aml model and forced by the time history of observed surface winds the shift in north pacific ocean climate that occurred around 1976 77 is focused on since this is the best observed example available after the 1976 77 shift the aleutian low deepened and moved to the southeast of its previous position this placed anomalous cyclonic flow over the north pacific the sst response as simulated by the ocean model consisted of two components a fast and local part and a delayed and remote part in the central pacific stronger westerlies cool the ocean by increased equatorward ekman drift here the dynamical cooling is sufficiently large that the surface fluxes damp the sst anomaly this ekman response is fast and local and cools the ssts beginning in 1977 and persistin

interdecadal variability over the north pacific in a multi century climate simulation interdecadal variability in the north pacific region is investigated in a 500 y control integration of the hamburg echam lsg coupled ocean atmosphere general circulation model the spectrum is predominantly red but a significant peak with a period of about 18 y is detected in the spectrum of sea surface temperature sst this peak is shown to be associated with an irregular oscillation that involves both the model ocean and atmosphere the sst sea level pressure and geopotential height at 500 hpa all undergo a primarily standing oscillation with an extensive monopole structure centered near the date line the surface anticyclone is situated to the northeast of the warm sst anomaly and there is a small westward tilt with height temporal changes are approximately in phase the anomalous surface heat flux accompanying the warm phase of sst is primarily out of the ocean but is compensated by anomalous warm advection by surface currents allowing the sst anomaly to persist oceanic thermocline anomalies propagate northward in the western pacific and lag the atmosphere indicating a disequilibrium with the atmosphere sub surface thermal advection appears to play an important role a comparison is made between the model s 18 y oscillation and oscillatory components identified in an analysis of the gisst observational sst dataset which have periods of approximately 6 and roughly 30 y

northern hemisphere winter atmospheric transient eddy heat fluxes and the gulf stream and kuroshio oyashio extension variability abstractspatial and temporal covariability between the atmospheric transient eddy heat fluxes i e t and q in the northern hemisphere winter january march and the paths of the gulf stream gs kuroshio extension ke and oyashio extension oe are examined based on an atmospheric reanalyses and ocean observations for 1979 2009 for the climatological winter mean the northward heat fluxes by the synoptic 2 8 days transient eddies exhibit canonical storm tracks with their maxima collocated with the gs and ke oe the intraseasonal 8 days 3 months counterpart while having overall similar amplitude shows a spatial pattern with more localized maxima near the major orography and blocking regions lateral heat flux divergence by transient eddies as the sum of the two frequency bands exhibits very close coupling with the exact locations of the ocean fronts linear regression is used to examine the lead lag relationship between interannual changes in the northward heat fluxes by the transient

a review on the applications of image logs in structural analysis and sedimentary characterization abstract image logs provide important information on lithology sedimentary textures paleoflow directions fractures and in situ stress analysis lacking of criteria used for establishing the image log facies limits the applications of image logs in sedimentary reservoir interpretation this paper provides a thoroughgoing review focusing on the recent applications of borehole image logs for sedimentological and structural description and interpretation and aims to establish image log facies which can provide guidelines in sedimentary reservoir interpretation this paper firstly summarizes the principles and basic characteristics of various imaging logging tools and then briefly introduces the pre processing workflow of the image log data then the generated images are used for depth and orientation shifts of cores by calibrating individual sedimentary and structural features descriptive and concise image log facies are established based on combinations of image textures including dip type dip pattern and color scheme and the characteristics as well as physical criteria for each individual image facies are summarized the established image log facies are then interpreted in terms of structural and sedimentological features such as lithology sedimentary structures vugs fractures and faults the image log facies and its stacking patterns are then used to interpret the lithofacies associations by calibrating with cores and conventional logs natural fractures and induced fractures are recognized by image logs and the principles of breakouts and drilling induced fractures for in situ stress analysis are reviewed then the applications of image logs in investigation of fracture attitudes and states as well as in computation of fracture parameters are summarized the procedures to evaluate fracture effectiveness through image logs are discussed at last the application of image logs for structural dip analysis is reviewed and image logs are used for recognizing faults fracture sets and attitudes of stratum through the dip patterns the basic procedures for paleocurrent reconstruction which includes dip picking of cross beddings structural dip determination and structural dip removal are reviewed then the paleocurrent directions of the lower cretaceous bashijiqike formation in the kuqa depression were reconstructed which could help further understanding of the depositional systems this review will help extend the utility of image logs in interpreting small to large scale sedimentary and structural features and bridges the gaps between well log analysis and sedimentary and structural interpretation

meridional shift of the kuroshio extension induced by response of recirculation gyre to decadal wind variations abstract the meridional shift of the kuroshio extension to decadal wind variations is examined by analyzing the hindcast simulation of a high resolution 1 12 1 12 north pacific ocean general circulation model ogcm and by conducting a series of idealized ogcm experiments the meridional shift of the kuroshio extension in the hindcast is consistent with observations and former studies using a series of sensitivity experiments in idealized settings the following possible mechanism for this shift is proposed the baroclinic rossby waves that arise in the northern half of the subtropical gyre cannot directly enter the kuroshio oyashio extension region due to the strong kuroshio extension jet when the rossby waves accompanying the negative positive sea surface height anomalies propagate westward and reach the region to the east of the recirculation gyre the difference in thermocline depth between the recirculation gyre and the region to its east becomes larger smaller resulting in stronger weaker baroclinic instabilities these stronger weaker instabilities cause a shallower deeper thermocline in the recirculation gyre to compensate for this shrinking stretching the recirculation gyre migrates southward northward leading to the southward northward shift of the kuroshio extension

characterization of braided river delta facies in the tarim basin lower cretaceous application of borehole image logs with comparative outcrops and cores abstract borehole electrical image log with core like presentation is an efficient way to conduct sedimentary description in the subsurface the key is to set up a series of geological diagnostic criteria the subsurface lower cretaceous bashijiqike formation in the kelasu belt kuqa depression described as a sedimentary facies of braided river delta front has measured a mass of borehole image logs and open hole logs at depths more than 6000 m combined with comparative outcrops limited cores and thin sections high quality borehole images were fine calibrated to reveal their sedimentary details with the aim of subtle sedimentary interpretation in the uncored intervals the image elements all have corresponding geological indications the lithologies are interpreted including mudstones siltstones fine and medium sandstones and conglomerates and the sedimentary structures are interpreted in terms of various bedding types scoured surface and stacking modes thus interdistributary bay sandy or conglomerate subaqueous distributary channel and channel mouth bar are interpreted based on the lithologies sedimentary structures and textures basal and top contacts and succession variations furthermore determination of paleo current direction using borehole image logs is proposed for some time but is far from mature and need to consider tectonic deformation settings of studied stratigraphy based on this the paleo current in the kelasu belt is interpreted to flow southward from the southern tianshan to the depression during the early cretaceous which is consistent with the results derived from the heavy mineral analysis however the subaqueous distributary channels could frequently migrate locally and the paleo current direction changed at localities with an offset angle varied between 30 and 150 regionally the scale of single sand body decreases lakeward and the sand body may stretch at a maximum distance of 685 1 m along the flow direction the diagnostic criteria and the workflow for borehole image interpretation in this study will have potential application to subsurface sedimentary description and guide sedimentary architecture where cores are not available

north pacific climate response to freshwater forcing in the subarctic north atlantic oceanic and atmospheric pathways abstract sudden changes of the atlantic meridional overturning circulation amoc are believed to have caused large abrupt climate changes over many parts of the globe during the last glacial and deglacial period this study investigates the mechanisms by which a large freshwater input to the subarctic north atlantic and an attendant rapid weakening of the amoc influence north pacific climate by analyzing four different ocean atmosphere coupled general circulation models gcms under present day or preindustrial boundary conditions when the coupled gcms are forced with a 1 sv sv 106 m3 s 1 freshwater flux anomaly in the subarctic north atlantic the amoc nearly shuts down and the north atlantic cools significantly the south atlantic warms slightly shifting the atlantic intertropical convergence zone southward in addition to this atlantic ocean atmosphere response all of the models exhibit cooling of the north pacific especially along the oceanic frontal zone consistent with paleoclimate recons

decadal variability of the kuroshio extension observations and an eddy resolving model hindcast abstract low frequency variability of the kuroshio extension ke is studied using observations and a multidecadal 1950 2003 hindcast by a high resolution 0 1 eddy resolving global ocean general circulation model for the earth simulator ofes in both the ofes hindcast and satellite altimeter observations low frequency sea surface height ssh variability in the north pacific is high near the ke front an empirical orthogonal function eof analysis indicates that much of the ssh variability in the western north pacific east of japan is explained by two modes with meridional structures tightly trapped along the ke front the first mode represents a southward shift and to a lesser degree an acceleration of the ke jet associated with the 1976 77 shift in basin scale winds the second mode reflects quasi decadal variations in the intensity of the ke jet both the spatial structure and time series of these modes derived from the hindcast are in close agreement with observations a linear rossby wave

a simple model of the decadal response of the ocean to stochastic wind forcing abstract a simple linear model is used to estimate the decadal response of the extratropical ocean to wind stress forcing assuming a flat bottom a mean state at rest and no dissipation the barotropic fields are governed by a time dependent sverdrup balance the baroclinic ones by the long rossby wave equation the ocean is bounded by a coast in the east and a radiation condition is used in the west at each frequency the baroclinic response consists of a forced response plus a rossby wave generated at the eastern boundary for zonally independent forcing the response propagates westward at twice the rossby phase speed the wind stress is assumed to be stochastic with a white frequency spectrum so the model represents the continuous excitation of the ocean interior by the weather fluctuations the model predicts the shape and level of the frequency spectra of the oceanic pressure field and their variation with longitude and latitude the baroclinic response is spread over a continuum of frequencies

interdecadal dynamics of the north pacific ocean abstract an isopycnal ocean model forced by ncep ncar reanalysis wind stresses and heat fluxes is used to study the interdecadal variability of the pacific ocean in the 1958 97 period a reasonable agreement is found between the model s modes of variability and those obtained by other researchers from both 100 years of observations and theoretical predictions in agreement with previous observational work decadal and interdecadal timescales have different descriptions and from this study it is suggested that they indeed have different dynamics this study focuses on the dynamics of the ocean s interdecadal variability that is of timescales of about 20 yr the decadal timescale that is 10 yr is briefly outlined and compared with previous studies it is found that atmospheric heat fluxes play a key role in establishing the interdecadal sst pattern in the midlatitudinal north pacific these fluxes would excite a high baroclinic mode igniting a series of events that move around the basin in midlatitu

seismic site response analysis for ottawa canada a comprehensive study using measurements and numerical simulations the surficial geology of the city of ottawa primarily consists of soft soil sediments with low shear wave velocities graphic 1 underlain by hard bedrock with very large shear wave velocities graphic 2 earthquake recordings show unusually large seismic amplification values for weak motion these unusually large seismic amplification factors were reconfirmed with the earthquake spectral ratio method using two stations the horizontal to vertical earthquake spectral ratio method using a single station and the horizontal to vertical spectral ratio technique using background noise these findings were the motivation for carrying out an extensive site response analysis using finite element modeling fem as a part of the seismic microzonation studies for the city of ottawa the fem results confirmed the large amplification ratios for weak motion recordings fem analysis was also carried out using a selection of strong motion time series for the study area the combined effect of the soil bedrock acoustic impedance contrast and the level of ground shaking on the variation of soil amplification factors for the fundamental frequency were investigated the maximum value of the soil amplification factor for the fundamental frequency increased with increasing impedance contrast ratios until the soil bedrock acoustic impedance contrast ratio reached values that were usually greater than 12 however the change in peak amplification was much less with subsequent increases in the contrast ratio beyond that value as expected the value of the soil amplification factors for the fundamental frequency decreased with increasing peak ground acceleration pga of the input motion due to nonlinear soil damping finally for the ottawa region a mathematical model is suggested for soil amplification factors at the fundamental frequency as a function of the soil bedrock acoustic impedance contrast ratio and the pga of the input motion 1 embed inline graphic 1 gif 2 embed inline graphic 2 gif

correction to recent cooling of the upper ocean the recent cooling signal in the upper ocean reported by lyman et al 2006 is shown to be an artifact that was caused by a large cold bias discovered in a small fraction of argo floats as well as a smaller but more prevalent warm bias in expendable bathythermograph xbt data these biases are both substantially larger than sampling errors estimated in lyman et al 2006

subduction of decadal north pacific temperature anomalies observations and dynamics abstract observations of oceanic temperature in the upper 400 m reveal decadal signals that propagate in the thermocline along lines of constant potential vorticity from the ventilation region in the central north pacific to approximately 18 n in the western pacific the propagation path and speed are well described by the geostrophic mean circulation and by a model of the ventilated thermocline the approximate southward speed of the thermal signal of 7 mm s 1 yields a transit time of approximately eight years the thermal anomalies appear to be forced by perturbations of the mixed layer heat budget in the subduction region of the central north pacific east of the date line a warm pulse was generated in the central north pacific by a series of mild winters from 1973 to 1976 and reached 18 n around 1982 after 1978 a succession of colder winters initiated a cold anomaly in the central north pacific that propagated along a similar path and with a similar speed as the warm anomaly then arrived in the west

structure and cycle of decadal variability of upper ocean temperature in the north pacific abstract yearly upper ocean in situ temperature anomaly data for the period 1961 90 are analyzed to reveal spatial structure and evolution of decadal variability in the north pacific ocean an eof analysis has been performed on individual temperature anomaly fields at upper ocean standard levels as well as simultaneously on the entire upper ocean data to depict the combined three dimensional structure in a coherent manner time evolution of anomaly fields is depicted by using a regression analysis the analyses detect the principal basin scale structure of decadal warm period dwp and decadal cold period dcp there is a well defined subsurface thermal anomaly pattern characterized by a prominent seesaw structure with opposite anomaly polarity between the midlatitude north pacific and the subtropical regions during a dwp a positive temperature anomaly is found in the central midlatitude upper ocean with the maximum at about 100 m depth this is accompanied by a corresponding negative anomaly in the

enso like interdecadal variability 1900 93 a number of recent studies have reported an enso like eof mode in the global sea surface temperature sst field whose time variability is marked by an abrupt change toward a warmer tropical eastern pacific and a colder extratropical central north pacific in 1976 77 the present study compares this pattern with the structure of the interannual variability associated with the enso cycle and documents its time history back to 1900 the analysis is primarily based on the leading eofs of the sst anomaly and anomaly deviation fields in various domains and the associated expansion coefficient or principal component time series which are used to construct global regression maps of sst sea level pressure slp and a number of related variables the use of anomaly deviations i e departures of local sst anomalies from the concurrent global mean sst anomaly reduces the influence of global mean sst trends upon the structure of the eofs and their expansion coefficient time series an important auxiliary time series used in this study is a southern oscillation index based on marine surface observations by means of several different analysis techniques the time variability of the leading eof of the global sst field is separated into two components one identified with the enso cycle related variability on the interannual timescale and the other a linearly independent residual comprising all the interdecadal variability in the record the two components exhibit rather similar spatial signatures in the global sst slp and wind stress fields the sst signature in the residual variability is less equatorially confined in the eastern pacific and it is relatively more prominent over the extratropical north pacific the corresponding slp signature is also stronger over the extratropical north pacific and its counterpart in the cold season 500 mb height field more closely resembles the pna pattern the amplitude time series of the enso like pattern in the residual variability reflects the above mentioned shift in 1976 77 as well as a number of other prominent features including a shift of opposite polarity during the 1940s

a local time dependent sverdrup balance in the eastern north pacific ocean direct observations of the dynamic balance between time dependent winds and deep ocean currents are described for the eastern north pacific ocean at 42 n 152 w currents from 150 to 4000 meters below the surface at frequencies from 0 01 to 0 1 cycle per day are significantly correlated with the wind stress curl derived from u s navy operational wind fields the horizontal currents are depth independent below 300 meters and they flow parallel to the potential vorticity gradient derived from the earth9s rotation and the large scale bottom topography these characteristics are expected for such periodic motions with horizontal scales larger than 500 kilometers and represent a generalized sverdrup balance between the atmospheric forcing and the oceanic response

is the north atlantic in sverdrup balance abstract evidence for the widespread assumption that sverdrup balance describes the dynamics of the north atlantic subtropical gyre is reviewed critically if the balance were to hold up to the edge of the gulf stream system then there is a serious conflict with existing estimates of the net meridional flux of heat if a recirculation region near the stream is excluded then one loses numerical agreement between a geostrophic calculation of the interior mass flux and the opposite gulf stream transport our conclusion is that while the linear vorticity balance may well apply over much of the north atlantic subtropical gyre there is little evidence supporting the special version called sverdrup balance even in the relatively quiescent region east of the mid atlantic ridge to the contrary simple order of magnitude estimates suggest that it is just as likely that the flows are dominated by bottom induced vertical velocities as they are directly driven by the wind stress curl

evidence for a wind driven intensification of the kuroshio current extension from the 1970s to the 1980s the spatial and temporal characteristics of oceanic thermal variations in the mixed layer and main thermocline of the midlatitude north pacific are distinctive suggesting different physical origins within the main thermocline 400 m depth the variability is dominated by a westward intensified pattern of decadal scale indicative of enhanced eastward geostrophic flow along the southern flank of the kuroshio current extension during the 1980s relative to the 1970s the authors argue that the decadal scale change in the strength of the kuroshio extension was a result of the dynamical adjustment of the oceanic circulation to a decadal variation in wind stress curl according to sverdrup theory four times daily wind stress fields from the national center for atmospheric research national centers for environmental prediction reanalysis project are used to compute the decadal change in sverdrup transport associated with the 1976 77 climate transition it is shown that the decadal changes in sverdrup transport inferred from the wind stress curl field and in observed geostrophic flow inferred from the upper ocean thermal field are consistent both in terms of spatial pattern and magnitude the decadal change in depth averaged geostrophic transport along the kuroshio extension referenced to 1 km is 11 6 sv similar to the sverdrup transport change 11 5 13 9 sv the decadal scale thermocline variation along the western boundary between 308 and 408n exhibits a lag of approximately 4 5 yr relative to the decadal variation in the basin wide wind stress curl pattern this delay may be indicative of the transient adjustment of the gyre scale circulation to a change in wind stress curl via long baroclinic rossby waves

the effect of magmatic intrusions on coalbed methane reservoir characteristics a case study from the hoskissons coalbed gunnedah basin australia magmatic intrusions can deteriorate coalbed methane reservoir quality by precipitating minerals in natural fracture and cleat system to date the effect of magmatic intrusions on coal rank and maturity has been studied extensively however their impact on fluid flow capacity and gas content is poorly investigated this study evaluates the impact of magmatic intrusions on reservoir characteristics of the hoskissons coal interval in the gunnedah basin eastern australia where numerous coal intrusion associations exist drill stem test dst borehole image logs and core data are used to determine fluid flow characteristics gas content and quality in 14 wells across the gunnedah basin the integration of borehole image logs and dst data analysis enables us to determine the existence openness and hydraulic conductivity of natural fracture and cleat systems in the hoskissons coal interval in addition available desorption canister data gas composition data and conventional well logs are interpreted to investigate probable thermal effect on gas content our analyses of different datasets reveal that the thickness of intrusions and their positions with respect to the hoskissons coal interval are variable in the studied wells permeability varies from 1091 md down to zero owing to heterogeneous fracture and cleat systems interpreted natural fracture cleat systems are well correlated with measured permeability from dst data analysis this highlights the role of open natural fractures cleats in fluid flow characteristics of the hoskissons coal interval results indicate that the mineralizing effect of hydro thermal fluids derived either from magmatic intrusions or coal itself is not a controlling factor in fluid flow capacity of the hoskissons coal interval in the studied wells this is described by either the distance between coal section and major intrusions in some wells or perhaps emplacement of intrusive bodies prior to development of cleat and natural fracture networks the destructive impact of intrusions on permeability is observed in one of the studied wells in which in situ stress perturbation is large due to presence of magmatic intrusions in sedimentary rocks variable in situ stress orientation can decrease fracture connectivity and consequently fluid flow properties are affected gas content largely varies in heat affected coal intervals this signature is the result of thermal effect fading with distance and is more pronounced when intrusions are in close proximity to coal intervals gas composition is variable in the studied wells gas composition data indicate that high quality desorbed gas with methane concentration higher than 90 could be found even in coal intervals which are heavily intruded c 2016 elsevier b v all rights reserved

interdecadal variations in the alaska gyre abstract climatic dynamic topography variations in the alaska gyre during the period 1968 1990 are described with an objective analysis of more than 12000 std and xbt stations and coads wind stress data interannual dynamic height and sst variations were correlated and were consistent with recently described large scale climatic shifts in the north pacific the gyre was cantered more to the east circulation appeared stronger and sst was lower during the early to mid 1970s than during the 1980s the aleutian low np and pna indices intensified during the interim but the response did not appear as a gyre spinup instead the associated wind stress anomalies forced a slowly varying dynamic height anomaly across the eastern and northern part of the gyre through ekman convergence which had the effect of displacing the gyre s low somewhat to the wsw in the 1980s the wind curl spectrum was white and the slow oceanic response was modelled as stochastic forced climate variability with a simple first order m

decadal shifts of the kuroshio extension jet application of thin jet theory abstractmeridional shifts of the kuroshio extension ke jet on decadal time scales are examined using a 1960 2004 hindcast simulation of an eddy resolving ocean general circulation model for the earth simulator ofes the leading mode of the simulated ke represents the meridional shifts of the jet on decadal time scales with the largest southward shift in the early 1980s associated with the climate regime shift in 1976 77 a result confirmed with subsurface temperature observations the meridional shifts originate east of the date line and propagate westward along the mean jet axis a trajectory inconsistent with the traditionally used linear long rossby waves linearized in cartesian coordinates although the phase speed is comparable to that in the traditional framework the zonal scale of these westward propagation signals is about 4000 km and much larger than their meridional scale to understand the mechanism for the westward propagation of the ke jet shifts the authors consider the limit of a thin

ecology of extant nummulitids and other larger benthic foraminifera applications in palaeoenvironmental analysis abstract larger benthic foraminifera lbf are important contributors to modern and ancient tropical shallow marine sediments over the past 30 years a substantial body of literature has built up on the ecology of modern lbf especially in terms of their environmentally sensitive depth distribution reproductive strategy and morphology and the symbiotic relationship between many larger foraminifera and photosynthetic algae over the same period the extinct genus nummulites which is abundant in eocene sediments of southern europe north africa and the arabian peninsula has increasingly been studied principally because significant volumes of hydrocarbons have been discovered reservoired within nummulitic limestones offshore tunisia and libya the modern ecological studies of lbf provide a powerful tool with which to develop palaeoecological models for fossil nummulites and other symbiont bearing larger foraminifera in the rock record

tectonic controls on carbonate platform evolution in southern papua new guinea passive margin to foreland basin the middle oligocene collision of the northern margin of the australian craton with a complex subduction system resulted in emplacement of a thrust mass and formation of a foreland basin that extended from the coral sea to the indian ocean the distribution of carbonate platform facies in southwestern papua new guinea reflects the transition from an eocene passive margin setting to the early stages of foreland basin evolution the initial basin configuration with terrigenous sedimentation confined to the proximal foredeep allowed carbonate deposition in the shallow environment adjacent to the peripheral forebulge subsequent southward migration of the basin resulted in a rapid increase in the area and thickness of carbonate platform deposition when the proximal foredeep became filled by detritus shed from the emerging orogen clastic sediments buried the platform and terminated carbonate deposition the history of the southern papua new guinea carbonate platform illustrates the paradox of carbonate deposition within the foreland basin whereby basin configuration initially encourages thick and extensive carbonate deposition but inevitably leads to terrigenous inundation and the demise of the carbonate platform

development of a papua new guinean onshore carbonate reservoir a comparative borehole image fmi and petrographic evaluation abstract the depositional and diagenetic controls on carbonate platform evolution are notoriously heterogeneous and difficult to determine from standard subsurface wireline logging techniques here a combined borehole image fmi fullbore formation microimager and petrographic study allowed evaluation of depositional and diagenetic trends across an australasian subsurface buildup that is a major recent gas discovery the elk and antelope gas fields are hosted in tertiary reefal platformal and associated deep water carbonates in the present day foothills region of the fold and thrust belt in the gulf province of papua new guinea a full suite of fmi logs 2800 m and 292 thin sections mainly from sidewall cores and cuttings from both platform flank and shallow water deposits were evaluated during this study despite the obvious scale differences between the datasets there was some correlation between the independent petrography and fmi studies for a picking major facies boundaries and b interpretation of depositional environments the latter particularly for slope and deep water deposits however thin section petrography proved critical in understanding primary depositional textures and secondary alteration features through the shallow water carbonates where complex diagenetic overprinting had strongly impacted original fabric and or in regions affected by gas smearing the petrographic study allowed more detailed examination of diagenesis and its impact on rock fabric which links to the fmi textures component analysis and depositional textures identified in thin section are good indicators of original depositional environment full fmi coverage allowed textural definition on a dm m scale identification and characterisation of vertical changes and likely large scale variations in depositional environments and sequences it was clear from combining the results of the two studies that diagenesis as well as depositional fabric had a strong impact on resultant fmi facies the diagenetic overprinting would have been difficult to extract from the fmi data without the benefit of the petrographic work this study shows the merits of selective petrographic analysis to calibrate the quality of facies interpretation from fmi images and proved critical for enhancing and in places revising initial fmi interpretations

interdecadal variability of the pacific ocean model response to observed heat flux and wind stress anomalies variability of the pacific ocean is examined in numerical simulations with an ocean general circulation model forced by observed anomalies of surface heat flux wind stress and turbulent kinetic energy tke over the period 1970 88 the model captures the 1976 77 winter time climate shift in sea surface temperature as well as its monthly seasonal and longer term variability as evidenced in regional time series and empirical orthogonal function analyses examination of the surface mixed layer heat budget reveals that the 1976 77 shift was caused by a unique concurrance of sustained heat flux input anomalies and very strong horizontal advection anomalies during a multi month period preceding the shift in both the central pacific region where cooling occurred and the california coastal region where warming occurred in the central pacific the warm conditions preceding and the cold conditions following the shift tend to be maintained by anomalous vertical mixing due to increases in the atmospheric momentum flux tke input into the mixed layer which deepens in the model after the shift from the early 1970s to the late 1970s and 1980s since the ocean model does not contain feedback to the atmosphere and it succeeds in capturing the major features of the 1976 77 shift it appears that the midlatitude part of the shift was driven by the atmosphere although effects of midlatitude ocean atmosphere feedback are still possible the surface mixed layer heat budget also reveals that in the central pacific the effects of heat flux input and vertical mixing anomalies are comparable in amplitude while horizontal advection anomalies are roughly half that size in the california coastal region in contrast where wind variability is much weaker than in the central pacific horizontal advection and vertical mixing effects on the mixed layer heat budget are only one quarter the size of typical heat flux input anomalies

modulation of decadal oscillation on surface chlorophyll in the kuroshio extension 1 in the study the responses of chlorophyll to decadal oscillations of kuroshio extension ke between two dynamical states are investigated using satellite data associated with the ke stable and unstable states the surface chlorophyll south of 35 n also undergoes two different contrast patterns low high chlorophyll 12 relative to multiyear mean corresponding to strengthened weakened ke jet i e stable unstable ke two distinct seesaw patterns exist on the north and south side of 35 n for both chlorophyll and sea level anomaly and on the east and west side of 153 e for both chlorophyll and eddy kinetic energy similarly the magnitude of spring bloom was also modulated by decadal variations of ke the spring bloom was suppressed enhanced relative to the magnitude of climatological spring bloom south of 35 n during the ke stable unstable period this change is significant and can reach 35 in extreme years of 2006 and 2009 the decadal variation of chlorophyll in the ke is likely modulated by vertical nutrient supply induced by divergences convergences associated with the westward propagation of wind induced rossby waves in the central and eastern north pacific ocean which are dynamically modulated by the north pacific gyre oscillations npgo or pdo pacific decadal oscillations

recent warming in the western north pacific in relation to rapid changes in the atmospheric circulation of the siberian high and aleutian low systems abstracton the basis of a new east asian winter monsoon eawm index and by analyzing the relationship between sea surface temperature sst anomalies and different atmospheric and oceanic factors in winter this study investigates the causes of the recent unusual warming in the western north pacific ocean analyses presented here emphasize the dual contribution from the atmosphere and ocean to the local sst variability with the relative importance of each contributor varying with the period and place during the period 1970 89 the eawm controlled mostly by the siberian high is predominantly responsible for the sst variability in most of the western north pacific whereas in the period 1990 2005 ocean dynamics become increasingly important in most places or even dominant in the kuroshio oyasio extension koe region the delayed response of the koe sst to basinwide wind stress curl forcing via rossby waves is epoch dependent and is significant at lags of 1 3 and 4 yr before 1990 but only at 1 yr aft

summertime evolution of decadal sea surface temperature anomalies in the midlatitude north pacific abstract to clarify the summertime evolution of decadal sea surface temperature sst anomalies and related physical processes in the midlatitudes of the north pacific numerical solutions of a three dimensional bulk mixed layer model are analyzed focusing on the contribution of the net shortwave radiative forcing at the sea surface a quantitative heat budget analysis for the ocean mixed layer relating to late 1980s decadal sst change reveals that the decadal sst anomalies decay from late spring to early summer over the entire midlatitudes of the north pacific this quasi seasonal decay of the decadal sst anomalies is controlled by an anomalous local thermal damping i e anomalous surface heat fluxes from midsummer to early autumn the anomalous net shortwave radiation flux associated with a meridional shift of the storm track acts to induce strong seasonal damping of the decadal sst anomaly in the northern kuroshio oyashio extension region in contrast in the north of the subtropical frontal region

dynamical role of mode water ventilation in decadal variability in the central subtropical gyre of the north pacific abstract decadal variability in the interior subtropical north pacific is examined in the geophysical fluid dynamics laboratory coupled model cm2 1 superimposed on a broad classical subtropical gyre is a narrow jet called the subtropical countercurrent stcc that flows northeastward against the northeast trade winds consistent with observations the stcc is anchored by mode water characterized by its low potential vorticity pv mode water forms in the deep winter mixed layer of the kuroshio oyashio extension koe east of japan and flows southward riding on the subtropical gyre and preserving its low pv characteristic as a thick layer of uniform properties the mode water forces the upper pycnocline to shoal and the associated eastward shear results in the surface intensified stcc on decadal time scales in the central subtropical gyre 15 35 n 170 e 130 w the dominant mode of sea surface height variability is characterized by the strengthening and weakening of the stcc because of variations

integrated 3 d reservoir modeling based on 3 d seismic the tertiary malampaya and camago buildups offshore palawan philippines three dimensional 3 d seismic interpretation and drilling results indicate complex sedimentary geometries of the malampaya and camago build ups offshore palawan philippines with localized progradation due to unidirectional offbank transport alternating with vertical aggradation successive reduction of size during buildup growth and backstepping of the protected landward margin in response to transgression ultimately appear to have triggered the demise of carbonate production and platform drowning the shallow water platform top sediments repeatedly show signs of subaerial exposure before reflooding a modeling functionality was developed to allow development of multiple scenario 3 d reservoir models in an exploration or appraisal stage the model enables merging of seismic scale observations based on 3 d volume and horizon analyses with subseismic scale information from well data however inherent noise within the seismic data introduced by the complex buildup morphology has resulted in inconsistent attribute distribution and fault dimming these difficulties are compounded by erratic velocity distribution within the limestone nonhyperbolic move out and a narrow relatively low frequency spectrum all of which prevent the use of the 3 d seismic volume as hard data but rather allow its use as a soft constraint for guiding the geological interpretation and ultimately the modeling process seismic data quality in such complex morphologic settings and scarcity of well data hamper greatly the use of geostatistically driven modeling approaches therefore a new functionality was developed within shell s proprietary integrated 3 d modeling suite geocap which allows deterministic model reservoirs using seismic horizon and volume interpretation sequence and cyclo stratigraphic architecture and the concept of reservoir rock type seismic velocity in clean carbonate formations is predominantly a function of porosity distribution to assess time to depth conversion uncertainty the reservoir rock type based models were first produced in the time domain only after differential 3 d depth conversion of these models could the scenarios be reconstructed in the depth domain the depth models subsequently were used to derive permeability and saturation 3 d distortions and thus hydrocarbon volumes for each deterministic scenario the models were then used for simulation purposes

covariations of sea surface temperature and wind over the kuroshio and its extension evidence for ocean to atmosphere feedback abstract satellite microwave measurements are analyzed revealing robust covariability in sea surface temperature sst and wind speed over the kuroshio extension ke east of japan ocean hydrodynamic instabilities cause the ke to meander and result in large sst variations increased reduced wind speeds are found to be associated with warm cold sst anomalies this positive sst wind correlation in ke is confirmed by in situ buoy measurements and is consistent with a vertical shear adjustment mechanism namely an increase in sst reduces the static stability of the near surface atmosphere intensifying the vertical turbulence mixing and bringing fast moving air from aloft to the sea surface south of japan the kuroshio is known to vary between nearshore and offshore paths these paths are very persistent and can last for months to years as the kuroshio shifts its path coherent wind changes are detected from satellite data in particular winds are high south of tokyo when the kuroshio takes the near

surface water hydrography of the kuroshio extension during the pliocene pleistocene climate transition abstract the pliocene pleistocene climate transition offers an opportunity to study the effect of glaciation on the ocean climate system we present a globigerinoides ruber 18 o record from ocean drilling program site 1208 kuroshio current extension kce this exclusively sub tropical foraminifer a summer fall mixed layer dweller at the kce affords the first long 3 0 ma to 1 8 ma orbital scale 2 5 kyr time step account of the sea surface in this area the section s temperature corrected benthic foraminiferal 18 o record constrains global changes in ice volume yielding a 18 o record that primarily reflects summer fall kce hydrography temperature and salinity a 0 3 decrease in 18 o values at 2 7 ma coincides with the onset of northern hemisphere glaciation indicating as much as 1 5 c warming during the summer fall to suggest that the subtropical north pacific sea surface provided heat and moisture for expanding ice sheets on the orbital scale the 41 kyr cycle that dominates high latitude climate is absent from the 18 o record indicating a stable surface water hydrographic regime on this time scale rather the 18 o record varies at and is coherent with the 19 kyr precessional component of the regional insolation curve supporting a direct response to subtropical insolation and insensitivity to extra regional forcing factors such as ice sheets

variation in subsurface water temperature and its link to the kuroshio current in the okinawa trough during the last 38 5 kyr abstract an 820 4 cm long piston core yk12 15 pc 01 was obtained from site ot 1b 28 07 15 n 127 11 97 e 1050 m water depth located in the middle of the okinawa trough in the southern east china sea ecs for core yk12 15 pc 01 oxygen and carbon isotopes 18o and 13c of planktic foraminifera globigerinoides ruber sensu stricto 250 355 m size fraction and globorotalia inflata 250 m size fraction together with total organic carbon toc nitrogen content tn and 13c of organic matter were analyzed for the last 38 5 thousand years kyr the 18o records of g ruber 18oruber and g inflata 18oinflata were used to estimate the temperature salinity of the surface and subsurface waters respectively in addition we estimated the vertical temperature gradient between the surface and the subsurface based on the difference in 18o between g ruber and g inflata 18oruber inflata the 18oinflata and 18oruber inflata indicate millennial scale variations in association with the oscillations in antarctic temperatures during the marine isotope stage mis 3 these results suggest that variations in subsurface temperature and vertical temperature gradient in the upper water column in the ecs were closely related to the atlantic bipolar seesaw during mis 3 the subsurface temperature in the ecs was higher at the beginning of greenland stadials when the antarctic temperatures showed the lowest values the warming of the subsurface is likely attributed to the stronger kuroshio transport high peaks in the toc and tn records coincide with the low peaks in 18oinflata high temperature suggesting higher primary productivity which is in good agreement with the interpretation of the intensified kuroshio however the subsurface warming was not recognized during herinch events indicating different temperature responses in the upper water column from other stadials

a theory of interdecadal climate variability of the north pacific ocean atmosphere system abstract a linear coupled model for the atmosphere upper ocean system is proposed to highlight the mechanisms of decadal to interdecadal climate variability in the north pacific in this model wind stress anomalies over the north pacific are related to anomalies in the meridional temperature gradient of the upper ocean the latter depends upon air sea thermodynamical feedbacks and meridional heat transport by upper ocean currents slow adjustment of the oceanic gyre circulation to the change in wind stress is accomplished by the forced baroclinic oceanic rossby waves which carry out the meridional heat transport uncoupled ocean dynamic adjustment can produce a weak decadal to interdecadal peak in the power spectrum of the meridional transport under temporal white noise wind stress forcing with organized spatial structure coupled dynamics produce a basin scale interdecadal oscillatory mode this mode arises from the dynamic coupling and the memory of the system residing in the slow gyre circulation ad

southwest pacific subtropical mode water a climatology we find that stmw extends across the entire width of the tasman sea in a very broad swath between the tropical convergence in the north just to the south of new caledonia the southeast australian coast in the west to as far south as 39 s likely due to the southward extension of the eac and eastwards along the southern stmw boundary in a meandering pathway that broadly follows the tasman front the total stmw volume across the region i e west of 180 varies seasonally by a factor of more than three between the estimated maximum of 6 6 0 5 1014 m3 in october and minimum of 1 9 0 4 1014 m3 in may interannual variations o 0 5 1014 m3 are also observed in the spatial extent of the thick mode water and its total volume el nino composite maps show an anomalous thickening of the stmw during the el nino year with october positive thickness anomalies in excess of 20 m total volume anomaly of 0 6 1014 m3 manifested throughout the subtropical gyre interior as far north as new caledonia total volume anomalies tend to be positive from january of the el nino year through to the july following 18 months the maximum correlation coefficient r 0 3 between 3 monthly stmw volume anomalies and the southern oscillation index is statistically significant at the 95 confidence level we conclude that during the anomalous cooling of the upper southwest pacific ocean in the el nino year winter time convection and stmw formation is enhanced across the region resulting in an el nino southern oscillation climate signal that is identifiable below the mixed layer by the increased stmw volume which persists through to the following winter finally some evidence for the possible decadal modulation of the stmw variability is also discussed

seasonality of decadal sea surface temperature anomalies in the northwestern pacific abstract the seasonality of the decadal sea surface temperature sst anomalies and the related physical processes in the northwestern pacific were investigated using a three dimensional bulk mixed layer model in the kuroshio oyashio extension koe region the strongest decadal sst anomaly was observed during december february while that of the central north pacific occurred during february april from an examination of the seasonal heat budget of the ocean mixed layer it was revealed that the seasonal scale enhancement of the decadal sst anomaly in the koe region was controlled by horizontal ekman temperature transport in early winter and by vertical entrainment in autumn the temperature transport by the geostrophic current made only a slight contribution to the seasonal variation of the decadal sst anomaly despite controlling the upper ocean thermal conditions on decadal time scales through the slow rossby wave adjustment to the wind stress curl when averaging over the entire koe region the cont