eddy resolving observation of the north pacific subtropical mode water abstracthydrographic data obtained by high resolution shipboard observations and argo profiling floats have been analyzed to study the mesoscale structure and circulation of the north pacific subtropical mode water stmw the float data show that in the late winter of 2008 stmw having a temperature of approximately 18 8 17 7 and 16 6 c formed west of 140 e at 140 150 e and east of 150 e respectively in the recirculation gyre south of the kuroshio extension after spring the newly formed stmw gradually shift southward decreasing in thickness simultaneously the stmws of 16 6 and 17 7 c are gradually stirred and then mixed in terms of properties in late fall they seem to be integrated to form a single group of stmws having a temperature centered at 17 2 c such stmw circulation in 2008 is much more turbulent than that in 2006 which was investigated in a previous study the difference between the two years is attributed to the more variable state of the kuroshio extension in 2008 associate

decadal response of the kuroshio extension jet to rossby waves observation and thin jet theory abstractthis study examines interannual to decadal variability of the kuroshio extension ke jet using satellite altimeter observations from 1993 to 2010 the leading empirical orthogonal function eof mode of sea level variability in the ke region represents the meridional shift of the ke jet followed by its strength changes with a few month lag this shift of the ke jet lags atmospheric fluctuations over the eastern north pacific by about three years broad sea level anomalies slas emerge in the eastern north pacific 3 4 years before the upstream ke jet shift and propagate westward along the ke jet axis in the course of the propagation the meridional scale of the slas gradually narrows and their amplitude increases this westward propagation of slas with a speed of about 5 cm s 1 is attributed to the westward propagation of the meridional shift of the jet consistent with the thin jet theory whose importance has been suggested by previous numerical studies in addition the westward propagatin

impact of aleutian low activity on the stmw formation in the kuroshio recirculation gyre region 1 to understand the formation of north pacific subtropical mode water stmw in the kuroshio recirculation gyre region the cause of stmw thickness variation is investigated using temperature profiles in a historically archived data set the thickness variation is predominantly controlled by the main thermocline depth mtd when the main thermocline deepens shoals the wintertime mixed layer depth can develop not develop and consequently thicker thinner stmw is observed in summer the large scale atmospheric forcing controlling the mtd is explored using a wind driven hindcast ocean model the mtd variation stems primarily from a baroclinic response in the ocean to the aleutian low al activity especially the meridional movement of the al exerts a remarkable influence

subsurface subtropical fronts of the north pacific as inherent boundaries in the ventilated thermocline the two subsurface temperature density fronts and the accompanying eastward currents in the central and southern part of the north pacific subtropical gyre are identified using the repeat hydrographic sections in the western part of the gyre and the sections over the whole gyre from the world ocean circulation experiment woce hydrographic program whp the northern eastward current corresponds to what has been known as the subtropical countercurrent stcc the countercurrent front is located typically near 24 8n and extends from the western boundary approximately to the international date line the previous suggestion that the stcc is located at the southern edge of north pacific subtropical mode water stmw is confirmed the front appears as the southern boundary of the lower potential vorticity pv apparent oxygen utilization aou waters on the isopycnals within the stmw layer the southern eastward current corresponds to what was recognized earlier but has not been documented in detail the southern countercurrent front is located near 188n west of the date line but shifts to the north east of the date line its eastern limit is around 165 8 wa t 258n the southern front corresponds to the southern boundary of the lower pv aou waters on the isopycnal surfaces of the wide su range including those of north pacific central mode water cmw while cmw seems to contribute largely to this low pv aou layer the contribution from other waters is still significant judging from the associated pv aou features in the thermocline both fronts can be regarded as inherent boundaries in the ventilated thermocline dividing the regions ventilated to distinctive degrees correspondence between the observational features of the countercurrents fronts and some of the previously proposed theories concerning the stcc are discussed

the north pacific climatology of winter mixed layer and mode waters abstract a climatology of the winter mixed layer in the north pacific ocean was constructed using hydrographic data from historical archives and recent observational programs including the world ocean circulation experiment the main aim was to provide better knowledge about source areas of upper water masses the authors have endeavored to preserve water properties near the frontal regions by keeping the smoothing scale as small as possible the resulting climatology shows considerable differences in the mixed layer depth and its water properties from those derived from the world ocean atlas woa maps of the potential vorticity field of the north pacific pycnocline are presented using the isopycnally averaged climatology hydrobase three distinct lateral minima of potential vorticity are identified as subtropical mode water stmw central mode water cmw and eastern subtropical mode water estmw in the western central and eastern parts of the subtropical gyre respectively the hydrobase isopy

deep atmospheric response to the north pacific oceanic subtropical front in spring abstract the north pacific subtropical front stf is a zone of high sea surface temperature sst gradients located around 25 n in the western basin and is most pronounced in spring the stf s atmospheric effects are investigated using satellite observations and an atmospheric reanalysis during april may along the stf surface wind stress curl turns weakly cyclonic in the general background of anticyclonic curls atmospheric column integrated water vapor displays a pronounced meridional maximum along this surface trough suggesting a deep vertical structure cyclonic wind curls occur intermittently at intervals of a few days along the stf in subsynoptic low pressure systems accompanying larger synoptic highs in the main storm track to the north in the subsynoptic surface lows convective rain takes place with deep upward motion moistening the entire troposphere the lows are enhanced by condensational heating leading to the formation of weak cyclonic wind curls the lows display vertical structure ch

subtropical mode water variation in the northwestern part of the north pacific subtropical gyre temporal variations of the north pacific subtropical mode water npstmw are studied with the proper temporal resolution for describing seasonal variation using monthly hydrographic data taken near the ogasawara islands npstmw is formed south of the kuroshio and the kuroshio extension in late winter and advected to the ogasawara site by the southwestward westward return flow of the kuroshio recirculation while npstmw is seen at the ogasawara site in almost all seasons npstmw with a higher core temperature is advected to this site in april and one with a colder core follows in and after june until january or february furthermore the npstmw core temperature shows considerable interannual variation this variation is very similar to that found in other regions away from the ogasawara site suggesting that it reflects the larger scale variation of npstmw and that this site would be suitable for monitoring the npstmw core temperature a significant correlation between the npstmw core temperature and the monsoon index which is defined as the difference in the sea level pressure between nemuro japan and irkutsk russia as an indicator of wintertime cooling indicates that npstmw contains a memory of wintertime cooling in the preceding winter

three subtropical fronts in the north pacific observational evidence for mode water induced subsurface frontogenesis 1 subsurface fronts in the subtropical north pacific were investigated by constructing a high resolution temperature climatology three distinct subtropical fronts stfs are identified which are the southern northern and eastern stfs according to their relative geographical locations the southern stf extends along 19 21 n west of the dateline while the northern and eastern stfs appear along 21 24 n and 26 n in the western and central subtropical gyre respectively our analysis showed that each of these stfs is associated with large negative meridional potential vorticity pv gradient in the thermocline below the front the northern stf is located on the southern edge of the kuroshio recirculation where the negative pv gradient occurs within a narrow density range and is maintained by the low pv core of the subtropical mode water stmw on the other hand the negative pv gradient at the eastern and southern stfs spans over a wide density range the eastern stf forms near the center axis of the subtropical gyre north of which the upper and lower portions of the central mode water cmw converge forming a thick low pv pool that maintains the negative pv gradient on the front similarly at the southern stf the negative pv gradient is due to a low pv pool to the north with the southernmost portion of the stmw stacked above the upper cmw advected from the central subtropical gyre it is concluded that the mode waters are essential for the north pacific stfs

ventilated thermocline strongly affected by a deep mixed layer a theory for subtropical countercurrent abstract the mixed layer thickness generally increases in the northward direction but its change seems to occur rather sharply in a narrow transition zone referred to as a mixed layer front here the author investigates the effects of the mixed layer front on the ventilated thermocline structure especially focusing on the generation mechanism of the subtropical countercurrent if the mixed layer front is not parallel to the surface density contour the fluid with minimum isopycnal potential vorticity is formed around the intersection of the mixed layer front and outcrop line if the mixed layer front slants northeastward and surface density is zonally uniform as seen in a numerical experiment carried out by kubokawa and inui in which the subtropical countercurrent was reproduced the minimum potential vorticity on a high density isopycnal occurs in the east while that in a low density isopycnal occurs in the west in the present study analytic solutions for a simple three layer model are presented f

differential formation and circulation of north pacific central mode water abstract a repeat hydrographic section along 165 e was analyzed to verify a westward extension of the formation region of the north pacific ocean central mode water cmw suggested by previous synoptic observations and to investigate the relation between the formation region and thermohaline fronts the cmw formation region extends at least as far west as 155 e much farther than recognized in a previous study based on climatology it is located in two interfrontal regions between the kuroshio extension front and the kuroshio bifurcation front kbf and between the kbf and the subarctic front where two types of cmw namely the lighter variety with potential density of 25 8 26 2 kg m 3 and the denser one of 26 3 26 4 kg m 3 are formed how this differential formation of cmw is reflected in its gyrewide distribution was examined using one time sections of the world ocean circulation experiment woce hydrographic program in the north pacific the main circulation paths of the two types of cmw diverge eas

effect of decadal kuroshio extension jet and eddy variability on the modification of north pacific intermediate water abstract salinity modifications in the north pacific intermediate water npiw core layer of 26 7 26 8 in the western north pacific ocean are investigated using temperature salinity data from available profiling float and hydrographic measurements in 2002 09 during 2002 05 when the kuroshio extension ke jet was intense and zonally elongated coherent positive salinity anomalies appeared along the inflow ke jet southeast of japan and in the downstream mixed water region east of 152 e broad scale negative salinity anomalies were detected south of the ke jet and in the upstream mixed water region west of 152 e the signs of these observed salinity anomalies were reversed in 2006 09 when the ke jet transitioned to a weakened and zonally contracted dynamic state by adopting an isopycnal advection diffusion model and conducting model runs with the time dependent advective field inferred from the eddy resolving satellite altimeter sea surface height data it is found that the observed salinity anomalie

subduction of north pacific central mode water associated with subsurface mesoscale eddy 1 during a shipboard high density hydrographic survey carried out in the western north pacific in fall 2008 we observed an anticyclonic eddy with a thickness of 150 dbar and a diameter of 40 km near 500 dbar depth at 27 5 n 145 e this subsurface mesoscale eddy contains the north pacific central mode water cmw which has anomalously low potential vorticity and high dissolved oxygen compared to the climatological cmw properties in the same region profiling float measurements detect similar cmw patches near and south of the kuroshio extension as well as southward cmw migration within the cmw formation region north of the kuroshio extension these observed facts suggest that cmw is subducted into the permanent pycnocline not only through large scale eastward advection near the northern edge of the subtropical gyre but also through southward cross frontal advection associated with the formation and migration of subsurface mesoscale eddies

variability of the kuroshio extension jet recirculation gyre and mesoscale eddies on decadal time scales abstract twelve years of sea surface height ssh data from multiple satellite altimeters are used to investigate the low frequency changes and the interconnections of the kuroshio extension ke jet its southern recirculation gyre and their mesoscale eddy field the dominant signal is characterized by the steady weakening of the ke jet recirculation gyre from 1993 to 1996 followed by a gradual strengthening after 1997 during the weakening period of 1993 96 the ke path migrated southward in general and this path migration reversed in direction during the strengthening period of the ke jet and recirculation gyre after 1997 by hindcasting the ssh signals using linear vorticity dynamics it was found that weakening strengthening in the ke jet and recirculation gyre is consistent with westward propagation of negative positive ssh anomalies generating in the eastern north pacific and strengthening during their westward propagation when the ke jet and recirculation gyre were in a weak mode during 19

influence of kuroshio path variation south of japan on formation of subtropical mode water abstractdistributions of subtropical mode water stmw in the northwestern part of the north pacific subtropical gyre were investigated using temperature salinity profiles from 2005 to 2011 with particular reference to the kuroshio meander and non meander path states south of japan in spring of meander years warm stmw with a potential temperature of 19 20 c potential density anomaly of 24 6 24 9 kg m 3 was found in the shikoku basin whereas cold stmw below 19 c was distributed throughout the southern region of japan in non meander years the warm stmw was formed in a spatially isolated and warm winter mixed layer ml in the shikoku basin where a local recirculation developed in association with the kuroshio meander path both the absence of horizontal mixing with a cold ml south of the kuroshio extension because of the spatially isolated ml and an increase in horizontal heat advection due to the westward flow associated with this local recirculation caused the ml warming in the shikoku basin a

cellular calcium pathways and isotope fractionation in emiliania huxleyi the marine calcifying algae emiliania huxleyi coccolithophores was grown in laboratory cultures under varying conditions with respect to the environmental parameters of temperature and carbonate ion concentration co32 concentration the ca isotope composition of e huxleyi s coccoliths reveals new insights into fractionation processes during biomineralization the temperature dependent ca isotope fractionation resembles previous calibrations of inorganic and biogenic calcite and aragonite unlike inorganically precipitated calcite the co32 concentration of the medium has no significant effect on the ca isotope composition of the coccoliths these results indicate a decoupling of the chemical properties of the bulk medium and the calcifying vesicle cellular ca pathways of e huxleyi indicate that fractionation cannot occur at the crystal surface as occurs during inorganic precipitation the dominant processes leading to the observed ca isotope fractionation pattern in e huxleyi are most likely the dehydration of the ca aquocomplex at the plasma membrane and the attachment of dissolved ca to proteins of ca channels the independence of ca isotope fractionation from co32 and the small temperature dependence of e huxleyi are also important for defining the isotopic signature of the oceanic ca sink since coccolithophores contribute to about half the global caco3 production a relatively uniform isotopic composition of the oceanic ca sink is further supported

the subtropical mode water circulation in the north pacific abstract historical hydrographic data are analyzed to investigate the seasonal variation of the subsurace pycnostad in the northwestern part of the north pacific and to relate it to the circulation of subtropical mode water stmw a gyre scale scheme of stmw circulation is deduced based on its observed climatological formation area and climatological geostrophic flow fields the deduced circulation is supported by climatological features of the subsurface hydrography presented separately for the non large meander period and the large meander period of the kuroshio zonal and meridional sections and isopycnal maps of potential vorticity and apparent oxygen utilization the kuroshio countercurrent composing the kuroshio recirculation system advects stmw formed in the wintertime thick mixed layer immediately off the kuroshio and the kuroshio extension during the non large meander period the recirculation system has a single anticyclonic gyre centered near 30 n 137 e and advects stmw formed off the kurosh

eddy mean flow interaction in the decadally modulating kuroshio extension system abstract satellite altimeter sea surface height ssh data of the past 16 years are used to investigate the decadal changes of the kuroshio extension ke system that oscillated between a stable and an unstable dynamic state during the stable state of 10 1992 06 1995 and 01 2002 12 2004 the ke jet was intense and had a northerly zonal mean path and a well defined southern recirculation gyre during the unstable state of 07 1995 12 2001 and 01 2005 present the ke jet had a reduced eastward transport and a more southerly flow path transitions between the two dynamic states are caused by the basin scale wind stress curl forcing in the eastern north pacific related to the pacific decadal oscillations pdos or the north pacific gyre oscillations npgos during the positive pdo or negative npgo phase the intensified aleutian low generates negative ssh anomalies in the eastern north pacific through ekman divergence as these wind induced negative ssh anomalies propagate to the west as baroclinic rossby waves they weaken the zonal ke jet and shift its path southward as its path is pushed southward 32 n the deep reaching ke jet has to ride over the shallow shatsky rise generating localized disturbances that lead to their subsequent development along the ke jet west of the shatsky rise the sequence opposite to that listed above occurs when the pdo npgo changes to its negative positive phase after the ke system transitions from a stable to unstable state the enhanced eddy interaction is found to strengthen both the southern recirculation gyre and quasi stationary meanders along the ke s upstream path this nonlinear eddy interaction is important in determining the amplitude of the observed decadal ke variability

a role of eddies in formation and transport of north pacific subtropical mode water 1 hydrographic data acquired during 2001 by argo profiling floats deployed in the kuroshio recirculation region are used to verify the inference that mesoscale eddies prevailing in the recirculation region play an important role in the formation and transport of north pacific subtropical mode water npstmw that is the deeper winter mixed layer is formed preferentially where the thermocline is deeper in association with anticyclonic eddies in the succeeding seasons mesoscale eddies retain npstmw during their southwestward movement from the npstmw formation region so that anticylonic eddies contribute substantially to the npstmw transportation the spatial distributions of the mixed layer depth in winter and the npstmw thickness in the succeeding seasons based on the float data suggest that they are affected by mesoscale eddies the float data also provide the statistical relations of these quantities against the thermocline depth which are consistent with our inference

observations of the subtropical mode water evolution from the kuroshio extension system study abstract properties and seasonal evolution of north pacific ocean subtropical mode water stmw within and south of the kuroshio extension recirculation gyre are analyzed from profiling float data and additional hydrographic and shipboard adcp measurements taken during 2004 the presence of an enhanced recirculation gyre and relatively low mesoscale eddy variability rendered this year favorable for the formation of stmw within the recirculation gyre stmw formed from late winter convection that reached depths greater than 450 m near the center of the gyre the lower boundary of stmw corresponding to 25 5 kg m 3 was set by the maximum depth of the late winter mixed layer properties within the deep portions of the stmw layer remained largely unchanged as the season progressed in contrast the upper boundary of the stmw layer eroded steadily as the seasonal thermocline deepened from late april to august vertical eddy diffusivity responsible for this erosion was estimated from a budget analysis of

formation and subduction of central mode water based on profiling float data 2003 08 abstract temperature and salinity data from argo profiling floats in the north pacific during 2003 08 have been analyzed to study the structure of winter mixed layer north of the kuroshio extension and the subsurface potential vorticity distribution in the subtropical gyre in relation to the formation and subduction of the central mode water cmw in late winter two zonally elongated bands of deep mixed layer extend at 33 39 and 39 43 n from the east coast of japan to 160 w these correspond to the formation region of the lighter variety of cmw l cmw and that of the denser variety of cmw d cmw and the recently identified transition region mode water trmw respectively in the western part of the l cmw and d cmw trmw formation regions west of 170 e the winter mixed layer becomes deeper and lighter to the east i e to the downstream as a result the formed mode water is reentrained into the mixed layer in the farther east in the following winter and modified to the lighter water and is thus

distribution of biologic anthropogenic and volcanic constituents as a proxy for sediment transport in the san francisco bay coastal system abstract although conventional sediment parameters mean grain size sorting and skewness and provenance have typically been used to infer sediment transport pathways most freshwater brackish and marine environments are also characterized by abundant sediment constituents of biological and possibly anthropogenic and volcanic origin that can provide additional insight into local sedimentary processes the biota will be spatially distributed according to its response to environmental parameters such as water temperature salinity dissolved oxygen organic carbon content grain size and intensity of currents and tidal flow whereas the presence of anthropogenic and volcanic constituents will reflect proximity to source areas and whether they are fluvially or aerially transported because each of these constituents have a unique environmental signature they are a more precise proxy for that source area than the conventional sedimentary process indicators this san francisco bay coastal system study demonstrates that by applying a multi proxy approach the primary sites of sediment transport can be identified many of these sites are far from where the constituents originated showing that sediment transport is widespread in the region although not often used identifying and interpreting the distribution of naturally occurring and allochthonous biologic anthropogenic and volcanic sediment constituents is a powerful tool to aid in the investigation of sediment transport pathways in other coastal systems

reemergence areas of winter sea surface temperature anomalies in the world s oceans 1 using datasets of sea surface temperature sst surface heat flux upper ocean thermal data and climatological temperature and salinity profiles we try to detect reemergence areas of winter sst anomalies in the world s oceans and describe characteristics of these areas in terms of mixed layer depth mld annual mean heat flux and properties of waters formed in winter mixed layer eventually seven reemergence areas are found four in the northern hemisphere and three in the southern hemisphere all areas have a large seasonal variation of mld and are the regions where annual mean heat fluxes are relatively small except for two regions in the northern hemisphere in the viewpoint of water properties it is found that these areas correspond to the mode water formation regions subtropical mode waters of the indian ocean south pacific south atlantic north pacific and north atlantic and north pacific central and north atlantic subpolar mode waters

evolution of the north pacific subtropical mode water in anticyclonic eddies anticyclonic eddies aes trap and transport the north pacific subtropical mode water stmw but the evolution of the stmw trapped in aes has not been fully studied due to the lack of eddy tracking subsurface observations here we analyze profiles from special designed argo floats that follow two stmw trapping aes for more than a year the enhanced daily sampling by these argo floats swirling around the eddies enables an unprecedented investigation into the structure and evolution of the trapped stmw in the aes the upper lower thermocline domes up concaves downward and this lens shaped double thermocline encompasses the thick stmw within the eddy core the lighter stmw 25 0 25 2 trapped in aes dissipates quickly after the formation in winter because of the deepening seasonal thermocline but the denser stmw 25 2 25 4 remains largely unchanged except when the ae passes across the izu ridge the enhanced diapycnal mixing over the ridge weakens the denser stmw appreciably while many aes decay upon hitting the ridge some pass through a bathymetric gap between the hachijojima and bonin islands forming a cross ridge pathway for stmw transport by contrast the north pacific intermediate water npiw underneath is deeper than the eddy trapping depth 600 m and hence left behind east of the izu ridge in argo climatology the shallow stmw 400 m intrudes through the gap westward because of the eddy transport while the npiw 800 m is blocked by the izu ridge

three compartment structure of subsurface intensified mesoscale eddies in the ocean mesoscale eddies are energetically dominant and pervasive over most of the world s oceans among them many are subsurface intensified with strongest signals in the ocean interior such as mode water eddies which trap water masses with distinctive properties and carry them over long distances with both argo profiling floats and atmospheric reanalysis data we showed that the structure of these eddies obeys a universal rule hence their three dimensional hydrographic fields can be readily reconstructed from very limited information more interestingly the volume of water trapped and moved by a mode water eddy is much greater than previously thought it has a three compartment structure in the vertical with the mode water being sandwiched between two layers of notably different properties and accounting for only a portion of the total trapped volume this article is protected by copyright all rights reserved

remote reemergence areas of winter sea surface temperature anomalies in the north pacific 1 taking account of water movement we detect pairs of formation and reemergence areas of winter sea surface temperature sst anomalies in the north pacific by analyzing various kinds of data sets two pairs of formation and reemergence areas are detected one pair is located in the northern subtropical gyre and water properties in both the formation and reemergence areas well correspond to those of north pacific central mode water npcmw another pair is found in the western to central part of the subtropical gyre the formation area corresponds well to that of north pacific subtropical water npstmw but the reemergence area is remote from the formation area examinations on upper ocean current field trace of temperature anomalies in the subsurface and change of water properties from the formation area to the reemergence area clearly indicate that waters with winter sst anomalies move from the formation area to the reemergence area in a year

effects of mesoscale eddies on subduction and distribution of subtropical mode water in an eddy resolving ogcm of the western north pacific abstract the effects of mesoscale eddies on the subduction and distribution of the north pacific subtropical mode water stmw are investigated using an eddy resolving ocean general circulation model ogcm first the subduction rate is calculated and the contribution of eddies to the subduction of stmw is estimated it is found that eddy subduction significantly contributes to the total subduction of stmw second eddy thickness transport and diapycnal flux are directly diagnosed to investigate the large scale eddy induced transport process of stmw the large southward eddy thickness transport in the stmw core density is consistent with eddy subduction the eddy transport on the isopycnal surface of stmw is directed down the thickness gradient and traverses the mean flow the meridional eddy transport streamfunction indicates two eddy circulation cells south of 30 n associated with the circulation of stmw these cells flatten density surfaces similar to the effect of the gent and mcwilliams gm schem

a mechanism for the recurrence of wintertime midlatitude sst anomalies abstract in the early 1970s namias and born speculated that ocean temperature anomalies created over the deep mixed layer in winter could be preserved in the summer thermocline and reappear at the surface in the following fall or winter this hypothesis is examined using upper ocean temperature observations and simulations with a mixed layer model the data were collected at six ocean weather stations in the north atlantic and north pacific concurrent and lead lag correlations are used to investigate temperature variations associated with the seasonal cycle in both the observations and the model simulations concurrent correlations between the surface and subsurface temperature anomalies in both the data and the model indicate that the penetration of temperature anomalies into the ocean is closely tied to the seasonal cycle in mixed layer depth high correlations extend to relatively deep shallow depths in winter summer lead lag correlations in both the data and the model at some of the stations

effect of mesoscale eddies on subtropical mode water variability from the kuroshio extension system study kess abstract forty eight profiling floats have been deployed in the kuroshio extension ke region since may 2004 as part of the kuroshio extension system study kess project by combining the float temperature salinity measurements with satellite altimetry data this study investigates the role played by mesoscale eddies in controlling the property changes in north pacific subtropical mode water stmw following a 3 yr period of low eddy activity in 2002 04 the ke showed a transition to a high eddy kinetic energy state in 2005 this transition is the result of delayed oceanic response to the 2002 shift in the basin scale surface wind forcing in connection with the pacific decadal oscillation the high eddy kinetic energy state of the ke is characterized by successive shedding of strong cold core rings into the recirculation gyre resulting from the interaction of the ke jet with the shatsky rise or the preexisting cutoff rings by transporting northern origin high potential vorticity pv ke water into t

formation region of north pacific subtropical mode water in the late winter of 2003 1 the mixed layer structure and properties in the formation region of the north pacific subtropical mode water stmw east of japan in the late winter of 2003 were examined using temperature and salinity data primarily from argo profiling floats the formation region extends south of the kuroshio extension between 30n and 35n and as far east as 175e it is characterized by a mixed layer with depths greater than 200db and meridionally uniform temperature between 16 5c and 18 2c associated with a mixed layer front at its southern edge the mixed layer in the formation region becomes colder fresher and denser toward the east leading to the formation of warmer saltier and lighter stmw in the western part of the region the spatial variation of the mixed layer depth in the formation region corresponds well with the underlying permanent thermocline depth index terms 4223 oceanography general descriptive and regional oceanography 4283 oceanography general water masses 4572 oceanography physical upper ocean processes citation oka e and t suga formation region of north pacific subtropical mode water in the late winter of 2003 geophys res lett 30 23 2205 doi 10 1029 2003gl018581 2003

subtropical countercurrent in an idealized ocean gcm abstract in the north pacific there is a shallow eastward current called the subtropical countercurrent which flows across the central subtropical gyre the present article studies the generation mechanism of the subtropical countercurrent reproduced in an ocean general circulation model gcm with a simple geometry driven by surface wind stress and surface buoyancy forcing in the ocean gcm the deep mixed layer occurs in the northern part of subtropical gyre and shoals abruptly in the central subtropical gyre the mixed layer front the narrow transition zone of the mixed layer depth slants from the western central subtropical gyre to the northeast and the low potential vorticity fluid is formed at the intersection of the mixed layer front and the outcrop line since the surface density is almost zonally uniform and the mixed layer front slants northeastward the minimum potential vorticity fluids on denser isopycnals are formed in the northeastern region while those on lighter isopycnals are form