laboratory experiments and observations of cyclonic and anticyclonic eddies impinging on an island 1 laboratory experiments are conducted to investigate the interactions of self propagating barotropic cyclones and baroclinic anticyclones with an island results are interpreted in the context of observations around okinawa island japan where ubiquitous arrivals of cyclones and anticyclones on the southeastern side of the island influence the flow around it thereby impacting both the ryukyu current s and the kuroshio s transport in the laboratory baroclinic anticyclones generate a buoyant current that flows clockwise around an island whereas barotropic cyclones generate a counterclockwise current in both cases the interaction is governed by conservation of circulation around the island which establishes a balance between the dissipation along the island in contact with the eddy and the dissipation along the island in contact with the generated current laboratory results and scaling analysis suggest that the interaction between an anticyclone cyclone and okinawa island should result in an instantaneous increase decrease of the ryukyu current transport and a delayed increase decrease of the kuroshio transport the estimated delays are in good agreement with those obtained with field measurements suggesting that the dynamics at play in the laboratory may be relevant for the flow around okinawa island

upper ocean currents around taiwan abstract current velocity measured by shipboard acoustic doppler current profiler sb adcp during 1991 2000 was used to study the upper ocean the composite and moored currents revealed a branch of the kuroshio that intruded steadily and persistently into the south china sea part of the intruded kuroshio flowed out of the south china sea through the northern luzon strait and re united with the main stream kuroshio the kuroshio had two velocity maximum cores southeast of taiwan but gradually combined into one as the kuroshio flowed north the kuroshio was deflected by the i lan ridge east of taiwan and the zonal running shelf break northeast of taiwan at the shelf break the kuroshio split with one branch intruding onto the shelf west of the luzon strait the kuroshio intruded into the south china sea some water flowed northward into the taiwan strait and re joined the kuroshio currents in the taiwan strait flowed primarily in a northward direction except for the southward current near the coast of mainland china north of the taiwan strait a branch of the northward flow followed the northern coast of taiwan to join the kuroshio the composite current varied consistently from season to season there was generally poor correlation between currents and local winds especially in the deep water regime remote forces were important in the currents around taiwan

a half century of geologic and geothermic investigations in iceland the legacy of kristjan saemundsson abstract one of the world s premier field geologists kristjan saemundsson led immense geological mapping programs and authored or co authored nearly all geological maps of iceland during the past half century including the first modern bedrock and tectonic maps of the whole country these monumental achievements collectively yield the most inclusive view of an extensional plate boundary anywhere on earth when kristjan began his work in 1961 the relation of iceland to sea floor spreading was not clear and plate tectonics had not yet been invented kristjan resolved key obstacles by demonstrating that the active rifting zones in iceland had shifted over time and were linked by complex transforms to the mid ocean spreading ridge thus making the concept of sea floor spreading in iceland acceptable to those previously skeptical further his insights and vast geological and tectonic knowledge on both high and low temperature geothermal areas in iceland yielded a major increase in knowledge of geothermal systems and probably no one has contributed more than he to icelandic energy development kristjan s legacy is comprised by his numerous superb maps on a variety of scales the high quality papers he produced the impactful ideas generated that were internationally diffused and the generations of colleagues and younger people he inspired mentored or otherwise positively influenced with his knowledge and generous attitude

topex poseidon observations of mesoscale eddies over the subtropical countercurrent kinematic characteristics of an anticyclonic eddy and a cyclonic eddy 1 relative dynamic heights and geostrophic fields were derived from topex poseidon altimetry data and then used to track mesoscale eddies over the subtropical countercurrent stcc the radii centers vorticities shearing deformation rates stretching deformation rates divergences and center velocities of all identified eddies over the stcc were determined using a model that assumes constant velocity gradients most eddies are concentrated in a zonal band near 22 n and there is an interannual variation in the number of eddies a case study was made for a cyclonic eddy and an anticyclonic eddy with time series of eddy kinematic parameters computed both eddies survive for 220 days and propagate westward along over 22 n 24 n to reach the kuroshio current east coast of taiwan where the eddies were dissipated and in turn affected the kuroshio current in many ways sea surface temperature data and drifter data confirm the existence of these two eddies the radii of both eddies vary and their shapes are mostly elliptical during propagation the anticyclonic eddy propagated almost westward with oscillating north south components and the mean speed is 8 3 km day the cyclonic eddy moved southwestward before reaching 130 e and then moved northwestward with a mean speed of 7 6 km day the propagations of these two eddies are basically consistent with the standard theory of eddy propagation but with larger speeds the propagating direction could be altered while passing steep bottom topography or merging with the other eddies index terms 4520 oceanography physical eddies and mesoscale processes 4576 oceanography physical western boundary currents 4512 oceanography physical currents 4594 oceanography physical instruments and techniques 4556 oceanography physical sea level variations

generation of internal waves by eddies impinging on the western boundary of the north atlantic abstractdespite the major role played by mesoscale eddies in redistributing the energy of the large scale circulation our understanding of their dissipation is still incomplete this study investigates the generation of internal waves by decaying eddies in the north atlantic western boundary the eddy presence and decay are measured from the altimetric surface relative vorticity associated with an array of full depth current meters extending 100 km offshore at 26 5 n in addition internal waves are analyzed over a topographic rise from 2 yr high frequency measurements of an acoustic doppler current profiler adcp which is located 13 km offshore in 600 m deep water despite an apparent polarity independence of the eddy decay observed from altimetric data the flow in the deepest 100 m is enhanced for anticyclones 25 2 cm s 1 compared with cyclones 4 7 cm s 1 accordingly the internal wave field is sensitive to this polarity dependent deep velocity this is apparent from the eddy modulated enhanc

eddy kuroshio interactions local and remote effects quasi geostrophic mesoscale eddies regularly impinge on the kuroshio in the western north pacific but the processes underlying the evolution of these eddy kuroshio interactions have not yet been thoroughly investigated in the literature here this interaction is examined with results from a semi idealized three dimensional numerical model and observations from four pressure sensor equipped inverted echo sounders piess in a zonal section east of taiwan and satellite altimeters both the observations and numerical simulations suggest that during the interaction of a cyclonic eddy with the kuroshio the circular eddy is deformed into an elliptic shape with the major axis in the northwest southeast direction before being dissipated the poleward velocity and associated kuroshio transport decrease and the sea level and pycnocline slopes across the kuroshio weaken in contrast for an anticyclonic eddy during the eddy kuroshio interaction variations in the velocity sea level and isopycnal depth are reversed the circular eddy is also deformed to an ellipse but with the major axis parallel to the kuroshio the model results also demonstrate that the velocity field is modified first and consequently the ssh and isopycnal depth evolve during the interaction furthermore due to the combined effect of impingement latitude and realistic topography some eddy kuroshio interactions east of taiwan are found to have remote effects both in the luzon strait and on the east china sea shelf northeast of taiwan

differential deformation on two sides of qiyueshan fault along the eastern margin of sichuan basin china and its influence on shale gas preservation abstract structural deformation is one of the main factors controlling shale gas preservation in silurian longmaxi formation in the sichuan basin the exploration practices demonstrate that the shale gas preservation condition in the areas to the west of the qiyueshan fault qysf along the eastern margin of the sichuan basin is better than that to the east in this study we synthesize seismic interpretation apatite fission track aft and triaxial rock mechanics experiment to determine the structural segmentation deformation time and shale fracturability of the qysf belt seismic interpretation shows that the qysf can be divided into three segments among which the central segment is transitional deformation zone the burial depth and deformation structure difference of silurian strata on the two sides of the fault are not variable obviously and shale gas preservation conditions are good aft simulation shows that the initial deformation time of chevron syncline thrust structure to the east of the qysf was 160 120 ma while that of the chevron anticline thrust structure deformation between the qiyueshan and the huayingshan was 100 80 ma and it gradually changes from the central to the north and south rock mechanics test reveals that under the same stress field the difficulty of fracture is influenced the dip angle of the shale bedding plane shale is most likely to produce fracture when the dip angle of bedding plane 34 37 but horizontal formation is difficult to rupture this proves that gentle anticline and syncline are more conducive to shale gas preservation therefore shale gas is mainly enriched in the core of gentle anticline and synclinal combined with the analysis of typical wells we believed that the two sides of the qysf are different in deformation time uplift amplitude and later multi directional stress reworking these cause differences in the direction scale and density of fractures in the strata thus affecting shale gas preservation on two sides of the qysf

blocking and westward passage of eddies in the luzon strait satellite observations have shown the abundance of generally westward propagating eddies in the subtropical regions in the north pacific ocean especially north of 10 n eddies transport mass and can significantly impact the circulation as well as the heat salt and nutrient balances of the western pacific marginal seas this paper uses a numerical model to examine the conditions when eddies can or cannot freely propagate westward through the luzon strait into the south china sea scs composite analyses on the 10 year model data show that the fates of eddies depend on the strength and path of the kuroshio in one path that exists mostly during fall and winter the kuroshio loops westward into the scs the potential vorticity pv across the current is weak and eddies are likely to propagate freely through the luzon strait in another path which exists mostly during spring and summer the kuroshio tends to leap directly northward bypassing the scs the pv across it strengthens and eddies are then blocked and are constrained to also follow the northward path nonlinear eddy current interaction and the existence of a cyclone north of the luzon island during the looping phase explain why eddies of both signs can pass through the strait it is shown also that the upstream state of the kuroshio in the western tropical pacific plays an important role in dictating the different paths of the kuroshio the looping leaping path is caused by a weakened stronger kuroshio transport related to the northward southward shift of the north equatorial current in wintertime summertime

eddy kuroshio interaction processes revealed by mooring observations off taiwan and luzon the influence and fate of westward propagating eddies that impinge on the kuroshio were observed with pressure sensor equipped inverted echo sounders piess deployed east of taiwan and northeast of luzon zero lag correlations between pies measured acoustic travel times and satellite measured sea surface height anomalies ssha which are normally negative have lower magnitude toward the west suggesting the eddy influence is weakened across the kuroshio the observational data reveal that impinging eddies lead to seesaw like ssha and pycnocline depth changes across the kuroshio east of taiwan whereas analogous responses are not found in the kuroshio northeast of luzon anticyclones intensify sea surface and pycnocline slopes across the kuroshio while cyclones weaken these slopes particularly east of taiwan during the 6 month period of overlap between the two pies arrays only one anticyclone affected the pycnocline depth first at the array northeast of luzon and 21 days later in the downstream kuroshio east of taiwan

observations of inflow of philippine sea surface water into the south china sea through the luzon strait abstract velocity observations near the surface made with argos satellite tracked drifters between 1989 and 2002 provide evidence of seasonal currents entering the south china sea from the philippine sea through the luzon strait the drifters cross the strait and reach the interior of the south china sea only between october and january with ensemble mean speeds of 0 7 0 4 m s 1 and daily mean westward speeds that can exceed 1 65 m s 1 the majority of the drifters that continued to reside in the south china sea made the entry within a westward current system located at 20 n that crossed the prevailing northward kuroshio path in other seasons the drifters looped across the strait within the kuroshio and exited along the south coast of taiwan during one intrusion event satellite altimeters indicated that directly west of the strait anticyclonic and cyclonic eddies resided respectively north and south of the entering drifter track the surface currents measured by the crossing drifters were much

energetics of eddy mean flow interactions along the western boundary currents in the north pacific abstractthe energetics of eddy mean flow interactions along two western boundary currents of the north pacific the kuroshio and ryukyu currents are systematically investigated using 22 years of n

downstream evolution of the kuroshio s time varying transport and velocity structure observations from two companion field programs origins of the kuroshio and mindanao currents okmc and observations of kuroshio transport variability oktv are used here to examine the kuroshio s temporal and spatial evolution kuroshio strength and velocity structure were measured between june 2012 and november 2014 with pressure sensor equipped inverted echo sounders piess and upward looking acoustic doppler current profilers adcps deployed across the current northeast of luzon philippines and east of taiwan with an eight month overlap in the two arrays deployment periods the time mean net i e integrated from the surface to the bottom absolute transport increases downstream from 7 3 sv 4 4 sv standard error northeast of luzon to 13 7 sv 3 6 sv east of taiwan the observed downstream increase is consistent with the return flow predicted by the simple sverdrup relation and the mean wind stress curl field over the north pacific despite the complicated bathymetry and gaps along the north pacific western boundary northeast of luzon the kuroshio bounded by the 0 m s 1 isotach is shallower than 750 dbar while east of taiwan areas of positive flow reach to the seafloor 3000 m both arrays indicate a deep counterflow beneath the poleward flowing kuroshio 10 3 2 3 sv by luzon and 12 5 1 2 sv east of taiwan time varying transports and velocities indicate the strong influence at both sections of westward propagating eddies from the ocean interior topography associated with the ridges east of taiwan also influences the mean and time varying velocity structure there this article is protected by copyright all rights reserved

typhoon induced upper ocean cooling off northeastern taiwan 1 the ocean cooling off northeastern taiwan induced by typhoons is complicated by the presence of the continental shelf of the east china sea and the kuroshio the cooling is primarily due to the upwelling of the kuroshio s subsurface water which accompanies the kuroshio s intrusion onto the shelf rather than the entrainment mixing generated by the wind the kuroshio s intrusion in this region has a seasonal variation being more substantial in winter than in summer previous studies found that the winter northeasterly monsoon creates an intrusion favored flow pattern while the reversed summer monsoon opposes it this study found that the strong northeast wind accompanied by a typhoon along a certain path could significantly alter the circulations on the shelf an intrusion event will be triggered via a similar mechanism as induced by the winter monsoon but at a faster pace a numerical study and observation data are provided to illustrate this mechanism

effects of mesoscale eddies on the volume transport and branch pattern of the kuroshio east of taiwan using satellite altimeter data and a long term altimetric transport index for the kuroshio inflow northeast of taiwan the effects of mesoscale eddies on the kuroshio volume transport kvt at the east taiwan channel and the branching pattern of the kuroshio east of taiwan are investigated at scales from those of individual events to interannual timescales both anticyclonic and cyclonic eddies are found to be able either to strengthen or weaken the kvt depending on the relative strength of mass convergence and divergence produced upstream and downstream of the eddies the major factor influencing the intensity of the kuroshio inflow is the meridional location of the eddies for single eddy events the kvt is significantly correlated with the latitude of the eddy s center the correlations being 0 44 and 0 48 for anticyclonic and cyclonic eddies respectively for dipole eddy events when the direction angle falls in the interval 40 150 240 300 the kvt anomaly tends to be positive negative furthermore low kvt events generally correspond to the formation of the ryukyu current branch which is also generated from strong mass divergence produced by the eddies in addition on interannual time scales the variation of kvt is closely related to the relative number of anticyclonic to cyclonic eddies west of 125 e with a correlation of 0 5 this article is protected by copyright all rights reserved

large variability of the kuroshio at 23 75 n east of taiwan synoptic features of the kuroshio at 23 75 n were quantified using nine ship based surveys between september 2012 and september 2014 the new ship based data set provides an unprecedented view of the kuroshio east of taiwan and suggest tremendous variability in its velocity hydrography volume heat and salt transports and water masses the kuroshio maximum velocity varied in 0 7 1 4 m s 1 the core current width delineated with the limit v 0 2 m s 1 ranged from 85 to 135 km and the thickness varied from 400 to 600 m a dual velocity maximum in the kuroshio core current though unexpected was observed in three of nine cruises the kuroshio core transport integrated from the directly measured velocity varied between 10 46 and 22 92 sv 1 sv 106 m3 s 1 the corresponding heat transport referenced to 0 c was 0 838 1 793 1015 w and the salt transport was 345 0 775 9 106 kg s 1 the geostrophic transport estimated using the thermal wind relation with the observed hydrographic data and reference velocity at 900 m is comparable to the directly measured kuroshio transport during most of the surveys suggesting the directly measured velocity is mostly in geostrophic balance

effects of the stcc eddies on the kuroshio based on the 20 year jcope2 reanalysis results abstract in this study 20 years of model reanalysis data are analyzed to study the effects of the subtropical countercurrent stcc eddies on the upstream kuroshio from east of luzon to east of taiwan the effects are assessed from individual events to interannual time scales the wind driven kuroshio is modified by the stcc eddies with high spatiotemporal variations the mass balance in the composite eddy events indicates that the strengthening and weakening of the kuroshio transport are locally caused by the mass convergence and divergence produced by the eddies the same analogy applies to the interannual time scale in the eddy rich years the upstream kuroshio is generally stronger because of wind forcing yet the strengthening is nonuniform because of modification by the eddies the larger number of warm eddies to the east of taiwan and luzon island further strengthen the jet whereas the larger number of cold eddies to the east of the luzon strait weaken the kuroshio in the luzon strait drifter trajectories show larger luzon strait intrusion during the occurrence of cold eddies the local weakening of the kuroshio by cold eddies leads to a weaker potential vorticity jump producing favorable conditions for the intrusion of a water mass into the south china sea

a two dimensional gravest empirical mode determined from hydrographic observations in the subantarctic front abstract south of australia where the baroclinicity in the subantarctic front extends almost to the seafloor the geopotential height of the sea surface and the vertical acoustic travel time exhibit a tight empirical relationship to each other and to the entire vertical structure of temperature t p salinity s p and specific volume anomaly p measurements of provide proxy estimates of the profiles tg p sg p and g p based on a two dimensional gravest empirical mode gem representation of the vertical structure fitted to 212 hydrographic stations a seasonal model was fitted in the near surface layers using additional historical data at each depth in the range 150 3000 dbar more than 96 of the variance in both the t and fields is captured by the gem representation during the subantarctic flux and dynamics experiment mar 1995 mar 1997 inverted echo sounders ies and current meters were moored in a 2d array along the woce sr3 transect south of australia at each i

a circumpolar gravest empirical mode for the southern ocean hydrography historical hydrographic data from the southern ocean are projected into a baroclinic stream function space generating a three dimensional gravest empirical mode gem parameterized by pressure geopotential height and longitude the low dimensional gem projection is intrinsically steady vertically coherent and equivalent barotropic the gem fields capture more than 97 of the total density and temperature variance in the antarctic circumpolar current region

mesoscale eddies in the northwestern subtropical pacific ocean statistical characteristics and three dimensional structures mesoscale eddy properties in the northwestern subtropical pacific ocean are investigated by analyzing 22 567 cyclonic eddies ces and 26 365 anticyclonic eddies aes detected from 19 year altimetric sea level records eddy occurrence frequency and kinetic energy are prevailingly high in the subtropical countercurrent zonal band between 19 degrees n and 26 degrees n and further elevated near the luzon taiwan coast a general superiority of aes is observed at most latitudes except between 19 degrees n and 22 degrees n where the ce number is larger the modal radius and mean lifespan of the ces aes are 134km and 11 2weeks 121km and 10 9weeks respectively after generation most eddies propagate westward with a mean speed of 7 2cms 1 and deflect northward following the kuroshio along the luzon taiwan coast three dimensional eddy structures are further explored with composite eddy images in five subregions constructed by surfacing argo temperature salinity data into altimeter detected eddy areas due to the existence of mode waters in the main thermocline eddy induced temperature anomaly exhibits a double core vertical structure which is especially evident in ce images because of the vertical water mass distribution salinity anomaly features a sandwich like pattern which is more evident in ae images also revealed is the significant structure difference in these five subregions eddies are greatly intensified as they approach the western boundary inducing larger temperature and salinity anomalies and influencing deeper ocean along the luzon taiwan coast aes are preferentially strengthened by the northward background flow

seasonal to interannual variations in the intensity and central position of the surface kuroshio east of taiwan 1 seasonal and interannual changes of surface kuroshio intensity and central position east of taiwan during 1993 2012 are investigated by quantitatively analyzing the satellite altimetry product the kuroshio moves inshore offshore off northeast of taiwan in winter summer whereas it has an offshore inshore path off southeast of taiwan in winter summer the seasonal change of heat flux over the east china sea shelf is found to cause the seasonality of the kuroshio central position off northeast of taiwan whereas the seasonal kuroshio movement off southeast of taiwan is found to be induced by the combined effect of the kuroshio changes through the luzon strait and the eastern luzon island in contrast to this y dependent path changes the kuroshio becomes weaker stronger as a whole east of taiwan in winter summer on the interannual time scales the kuroshio throughout the eastern coast of taiwan intensifies and has a concurrent offshore path during the periods of 1995 1997 and 2004 2007 the relative intensity of cyclonic eddies to anticyclonic eddies off eastern taiwan are found to contribute to these interannual kuroshio changes

modulation of kuroshio transport by mesoscale eddies at the luzon strait entrance measurements of kuroshio current velocity at the entrance to luzon strait along 18 75 n were made with an array of six moorings during june 2012 to june 2013 strong positive relative vorticity of the order of the planetary vorticity f was observed on the western flank of the kuroshio in the upper 150 m on the eastern flank the negative vorticity observed was about an order of magnitude smaller than f kuroshio transport near its origin is computed from direct measurements for the first time kuroshio transport has an annual mean of 15 sv with a standard deviation of 3 sv it is modulated strongly by impinging westward propagating eddies which are identified by an improved eddy detection method and tracked back to the interior ocean eight kuroshio transport anomalies 5 sv are identified seven are explained by the westward propagating eddies cyclonic anticyclonic eddies decrease increase the zonal sea level anomaly sla slope and reduce enhance kuroshio transport large transport anomalies of 10 sv within o 10 days are associated with the pairs of cyclonic and anticyclonic eddies the observed kuroshio transport was strongly correlated with the sla slope correlation 0 9 analysis of sla slope data at the entrance to luzon strait over the period 1992 2013 reveals a seasonal cycle with a positive anomaly i e an enhanced kuroshio transport in winter and spring and a negative anomaly in summer and fall eddy induced vorticity near the kuroshio has a similar seasonal cycle suggesting that seasonal variation of the kuroshio transport near its origin is modulated by the seasonal variation of the impinging mesoscale eddies

interannual to decadal variability in the bifurcation of the north equatorial current off the philippines satellite altimeter sea surface height ssh data from the past 17 yr are used to investigate the interannualto decadal changes in the bifurcation of the north equatorial current nec along the philippine coast the nec bifurcation latitude migrated quasi decadally between 108 and 158n with northerly bifurcations observed in late 1992 1997 98 and 2003 04 and southerly bifurcations in 1999 2000 and 2008 09 the observed necbifurcationlatitudecanbeapproximatedwellbythesshanomaliesinthe128 148nand1278 1308ebox east of the mean nec bifurcation point using a 1 layer reduced gravity model forced by the ecmwf reanalysis wind stress data the authors find that the ssh anomalies in this box can be simulated favorably to serve as a proxy for the observed nec bifurcation with the availability of the long term reanalysis wind stress data this helps to lengthen the nec bifurcation time series back to 1962 although quasi decadal variability was prominent in the last two decades the nec bifurcation was dominated by changes with a 3 5 yr period during the 1980s and had low variance prior to the 1970s these interdecadalmodulationsin the characteristics of the nec bifurcation reflect similar interdecadal modulations in the wind forcing field over the western tropical north pacific ocean although the nec bifurcation on interannual and longer time

the kuroshio east of taiwan moored transport observations from the woce pcm 1 array observations from the woce pcm 1 moored current meter array east of taiwan for the period september 1994 to may 1996 are used to derive estimates of the kuroshio transport at the entrance to the east china sea three different methods of calculating the kuroshio transport are employed and compared these methods include 1 a direct method that uses conventional interpolation of the measured currents and extrapolation to the surface and bottom to estimate the current structure 2 a dynamic height method in which moored temperature measurements from moorings on opposite sides of the channel are used to estimate dynamic height differences across the current and spatially averaged baroclinic transport profiles and 3 an adjusted geostrophic method in which all moored temperature measurements within the array are used to estimate a relative geostrophic velocity field that is referenced and adjusted by the available direct current measurements the first two methods are largely independent and are shown to produce very similar transport results the latter two methods are particularly useful in situations where direct current measurements may have marginal resolution for accurate transport estimates these methods should be generally applicable in other settings and illustrate the benefits of including a dynamic height measuring capability as a backup for conventional direct transport calculations the mean transport of the kuroshio over the 20 month duration of the experiment ranges from 20 7 to 22 1 sv 1 sv 106 m3 s 1 for the three methods or within 1 3 sv of each other the overall mean transport for the kuroshio is estimated to be 21 5 sv with an uncertainty of 2 5 sv all methods show a similar range of variability of 10 sv with dominant timescales of several months fluctuations in the transport are shown to have a robust vertical structure with over 90 of the transport variance explained by a single vertical mode the moored transports are used to determine the relationship between kuroshio transport and sea level difference between taiwan and the southern ryukyu islands allowing for long term monitoring of the kuroshio inflow to the east china sea

observations of island wakes at high rossby numbers evolution of submesoscale vortices and free shear layers abstractoceanic vortex evolution on the lee side of taiwan s green island 7 km in diameter where the kuroshio flows at a speed of 1 1 5 m s 1 is observationally examined and compared to theori

eddy transport of heat and thermocline waters in the north pacific a key to interannual decadal climate variability abstract high resolution xbt transects in the north pacific ocean at an average latitude of 22 n are analyzed together with topex poseidon altimetric data to determine the structure and transport characteristics of the mesoscale eddy field based on anomalies in dynamic height 410 eddies are identified in 30 transects from 1991 to 1999 including eddies seen in multiple transects over a year or longer their wavelength is typically 500 km with peak to trough temperature difference of 2 2 c in the center of the thermocline the features slant westward with decreasing depth by 0 8 of longitude on average from 400 m up to the sea surface this tilt produces a depth varying velocity temperature correlation and hence a vertical meridional overturning circulation in the mean 3 9 sv sv 106 m3 s 1 of thermocline waters are carried southward by the eddy field over the width of the basin balanced mainly by northward flow in the surface layer corresponding northward heat transport is 0 086 0 012 pw

vertical structure and transport on a transect across the north atlantic current near 42 n time series and mean a new method is presented for combining historical hydrography with the acoustic travel time measurements from an inverted echo sounder ies to obtain time series of full water column profiles of temperature t and specific volume anomaly hydrography is used to demonstrate that profiles constructed from the ies measurement account for more than 90 of the t and variance through the main thermocline range horizontal gradients between neighboring pairs of instruments when combined with measurements from bottom pressure sensors and deep current meters provide accurate estimates of absolute geostrophic velocity profiles a section of iess and current meters across the north atlantic current nac along world ocean circulation experiment line acm6 near 42 5 n is analyzed using these methods and the eulerian mean temperature and absolute velocity sections are calculated the mean transport for the combined nac and northward flow within the inshore portion of the mann eddy is 146 13 106 m3 s 1 the temporal standard deviation of the northward transport is 41 106 m3 s 1 arising not only from changes in the transport of the nac but also from lateral shifts of the currents and eddies captured by the fixed span of moorings assumption of a level of no motion at the bottom and at 2000 dbar underestimates the true absolute transport by 33 or 60 respectively historical measurements indicate that 50 60 106 m3 s 1 circulates within the mann eddy adjacent to the north atlantic current thus 86 96 106 m3 s 1 appears to be throughput at the acm6 line because the throughput observed on the acm6 line considerably exceeds the combined historical estimates of northward and eastward outflow from the newfoundland basin of 30 106 m3 s 1 these measurements suggest a substantial 50 106 m3 s 1 recirculation or southward flow within the newfoundland basin in addition to the historical recirculation within the mann eddy