development of a simple upper ocean and sea lce model abstract results are described for three simple numerical models of the upper ocean and sea ice with prescribed atmospheric forcing the ability of each model version to simulate the observed sea surface temperature sst is assessed as a basis of comparison for future coupled experiments with atmospheric gcm s lie upper ocean model versions raw from a slab of fixed thickness to a variable depth mixed layer above a variable exponential temperature gradient representing the seasonal thermocline sea ice thickness is determined thermodynamically by local melting or accretion and the effects of ice transport and leads are neglected each version is tested by integrating to equilibrium with horizontal advection neglected using monthly climatological atmospheric data for a selected north south section in the mid pacific ocean and the results for different model versions are compared with each other and with available observations it is found that the fixed slab version gives realistic sea ice thickness a

mesozoic orogenic gold deposits in mexico abstract although orogenic gold deposits in mexico were mostly formed during the cenozoic they started forming during the late cretaceous or perhaps even earlier mylonitic zones in the oaxacan metamorphic complex span either permo triassic or triassic jurassic ages but none of these have been formally associated with the existing orogenic gold occurrences given the current scarcity of age data for them any interpretation concerning the age patterns or distribution of orogenic gold deposits in mexico other than those in the sonoran belt is hitherto deemed to be precarious a few known mesozoic examples are part of the quitovac la choya deposits in the caborca orogenic gold belt cogb in sonora and los uvares in the los cabos block southernmost part of the baja california peninsula the cogb constitutes the most economically important and geologically consistent mineralized area in mexico with respect to orogenic gold deposits also the cogb arguably correlates with the mother lode trend in california and nevada whereas the cluster of deposits in the los cabos block may have correspondent similarly mineralized areas in mainland southwestern mexico jalisco block other areas with orogenic gold deposits in mexico which have been traditionally overlooked or scantly mentioned are the northernmost part of the baja california peninsula and the arteaga and oaxacan metamorphic complexes although no geochronological data are available from these besides the overly lack of such data one of the typical problems concerning the characterization and metallogenesis of orogenic deposits in mexico has been their inaccurate or incorrect ascription to other genetic paradigms or types of deposits such as epithermal or porphyry cu au deposits therefore misguiding exploration efforts the formation of orogenic gold deposits in mexico has been commonly associated with the laramide orogeny in association with cataclastic or mylonitic deformation and shear zones their depth of formation under lithostatic pressure has ben estimated at a range between 3 and 10 km alteration assemblages in them are generally dominated by quartz sericite pyrite and may be carbonate rich the hypogene mineralogy of orogenic gold deposits in mexico is normally dominated by sulfides like pyrite galena sphalerite and whereas gold normally occurs as electrum also known as unspecified ag rich gold au rich silver or as free gold the latter may either be a hypogene or supergene mineral in which case it is likely to be due mostly to the leaching off of ag from electrum te rich associations are rare and have complex parageneses that consist typically of silver and or gold tellurides the mineralizing fluid precipitation into quartz veins occurred at temperatures 350 c and are co 2 rich deeply seated crustal brines from metamorphic sources with salinities typically ranging between 2 and 10 wt nacl equiv but attaining up to 33 wt nacl equiv

latest cretaceous early paleogene boom of porphyry cu mineralization associated with the laramide magmatic arc of mexico abstract porphyry copper and associated deposits are widespread through most northwestern mexico particularly in sonora and sinaloa in the northwestern part of the country these deposits belong to a nw se trending copper belt that extends from southwestern usa to southern mexico the copper mineralization is clearly linked to subduction related calc alkaline plutons formed during the eastward migration of the cordilleran magmatic arc largely coincident in time and space with the laramide orogeny 80 40 ma the economically most important porphyry copper deposits were emplaced in the southwest margin of the north american craton the porphyry copper mineralization was formed during the latest cretaceous to early paleogene between 75 and 52 4 ma but it was particularly fertile between 69 and 54 ma when the larger copper concentrations were deposited to form the famous copper cluster of arizona new mexico and sonora during this time more than half of the total porphyry copper related metals of the entire cordillera was deposited this large copper accumulation developed south of the classical flat slab laramide province characterized by uplift of large crustal blocks and mostly amagmatic conditions an inferred slab tear zone separated this zone from a slab segment above which asthenospheric magma flux favored copper concentration the mexican porphyry copper belt accounts for 30 deposits out of which the buenavista del cobre 30 mt cu and the la caridad 8 mt cu are the most relevant more to the south close to the boundary between sonora and sinaloa the porphyry copper deposits are smaller

radiometric and kinematic evidence for middle jurassic strike slip faulting in southern mexico related to the opening of the gulf of mexico one of the least known aspects of the evolution of the gulf of mexico is the nature and location of shear zones along which the relevant continental fragments were displaced the sierra de juarez mylonitic complex located in southern mexico is a polyorogenic north northwest trending structure here we report u pb mylonitization dates of 165 20 ma for igneous zircon from the syntectonic san felipe granite and an integrated 40 ar 39 ar age of 169 3 1 7 ma from synkinematic muscovite both of which indicate a middle jurassic age for the strike slip event along the sierra de juarez mylonitic complex this event therefore occurred during the opening of the gulf of mexico and we propose that the shear zone was kinematically related to the southeast displacement of the yucatan block

boundary layer upper ocean and ice observations in the greenland sea marginal ice zone during the 1984 marginal ice zone experiment a coordinated ocean boundary layer and mixed layer experiment was carried out in concert with a complete heat and mass balance study in the summer marginal ice zone miz of the greenland sea the measurements were made at two drifting ice stations and included observations of ocean boundary layer turbulence profiles of water temperature salinity and velocity ice ablation ice concentration solar radiation and spectral albedos ocean conditions were found to be extremely variable the ice and water velocities were heavily influenced by tidal and inertial motions with amplitudes from 6 to 12 cm s 1 in the course of the drift a 30 km eddy was crossed wherein ice and water velocities exceeded 15 cm s 1 the northern extension of the east greenland polar front was encountered and a northward flow of atlantic water into the arctic basin was observed below the eastern edge of the front but the drift station never moved quite far enough west to be caught in the southward transport of arctic surface water heat from the ocean was a major factor in ice melt and when the ice was over atlantic water it was the dominant factor the events that had the greatest impact on the ice were two outbreaks during which off ice winds blew the ice across warm ice edge ocean fronts once south of these fronts and over surface water as warm as 1 c the ice bottom melted at rates up to 100 kg m 2 d 1 the rapid changes in stratification associated with the outbreaks had a dramatic impact on the drag and heat transfer coefficients the drag coefficient relative to the square of the relative water velocity at 30 m ranged from 0 002 to 0 02 and averaged 0 006 the heat transfer coefficient relative to the friction velocity u and the mixed layer temperature elevation above freezing ranged from 0 0025 to 0 009 and averaged 0 0038 in agreement with the idea that stratification inhibits turbulent exchange the heat transfer coefficient decreased when stratification increased in fact the observed melt rates can be simulated well if molecular heat and salt transfer through a thin near surface laminar boundary layer are accounted for as well as transfer through the turbulent outer boundary layer also in agreement with turbulent boundary layer theory the drag coefficient decreased when stratification increased slightly above neutral however for the large increases in surface stratification the drag coefficient increased this was due to the generation of internal gravity waves by ice bottom roughness because the surface exchange coefficients are so sensitive to surface stratification which is in turn highly variable in the miz accurate simulations of ice motion and ice melt will require realistic estimates of stratification and a good understanding of the relation between the ice ocean interactions and upper ocean conditions

swell and sea in the emerging arctic ocean ocean surface waves sea and swell are generated by winds blowing over a distance fetch for a duration of time in the arctic ocean fetch varies seasonally from essentially zero in winter to hundreds of kilometers in recent summers using in situ observations of waves in the central beaufort sea combined with a numerical wave model and satellite sea ice observations we show that wave energy scales with fetch throughout the seasonal ice cycle furthermore we show that the increased open water of 2012 allowed waves to develop beyond pure wind seas and evolve into swells the swells remain tied to the available fetch however because fetch is a proxy for the basin size in which the wave evolution occurs thus both sea and swell depend on the open water fetch in the arctic because the swell is regionally driven this suggests that further reductions in seasonal ice cover in the future will result in larger waves which in turn provide a mechanism to break up sea ice and accelerate ice retreat

the opening of the gulf of california near loreto baja california mexico from basin and range extension to transtensional tectonics abstract detailed structural field analyses of faults and fractures have led to the reconstruction of the tectonic evolution of the loreto region baja california mexico during the opening of the gulf of california three main tectonic events have been recognized i formation of large scale radial structures along the future main gulf escarpment here interpreted as associated with emplacement of magmatic bodies at shallow levels during the beginning of extension processes in early middle miocene ii ne sw extension basin and range event active since 15 ma producing nw se normal dip slip faults in the oligo miocene volcaniclastic basement and indicating high extension rates iii transtensional tectonics recorded especially in the plio quaternary sediments and associated with the activation of nw se dextral strike slip faults and n s normal faults the tectonic structures related to the basin and range extension are sealed by the plio quaternary sediments of the loreto basin and by the volcanics of the mencenares volcanic complex a huge volcanic field interfingering with the sedimentary succession of the basin

the great whirl observations of its seasonal development and interannual variability 1 in situ measurements are used together with sea surface height data to study the development and variability of the great whirl gw a large quasi stationary anticyclone that appears off the coast of somalia during the southwest monsoon season we find that anticyclonic circulation indicative of the gw appears on average in april almost two months before the onset of the southwest monsoon winds this early initiation is coincident with the arrival of annual rossby waves at the western boundary with the onset of the monsoon winds in early june the gw proper intensifies quickly remaining at its peak throughout july august and september and dissipating about one month after the winds have died the gw is present for an average 166 30 days per year and the position of its northern flank close to 9 n coincides with the latitude of zero wind stress curl the intraseasonal variability of the gw is intense as a result of mutual advection with one to three flanking cyclones which accompany the gw 70 of the time and tend to circulate clockwise around it there is no consistent seasonal pattern for the development or dissipation of the gw although movement to the southwest is common toward the end of the season the gw of 1995 deepened from 200 m in june to over 1000 m in september and strengthened from a swirl transport of 10 to 60 sv cool waters in its core resulted from advection via the somali current and some local vertical mixing

on some possible interactions between internal waves and sea ice in the marginal ice zone the ice edges of the world ocean are generally the site at times when winds are blowing off the ice of regularly spaced surface bands of ice floes these bands have size scales of the order of 1 10 km and their long axes are oriented approximately normal to the wind direction available oceanic temperature and salinity data from the bering and greenland sea ice edge regions suggest that these ice bands are commonly underlain by a two layered density structure which is maintained by net melting along the ice edges linear internal wave theory is applied to these data to compute first mode interfacial wave phase speeds a simple analytical model is developed that demonstrates the feasibility of generation of such interfacial internal waves by the stress discontinuity due to off ice winds blowing over either a stationary or a moving ice edge it is qualitatively shown that the computed internal wave phase speeds and wavelengths are under many conditions compatible with the speeds and spacings of the surface ice bands this compatibility suggests in turn that coupling between internal waves and ice bands may commonly occur some possible implications of the generation and presence of these internal waves upon other ice edge processes such as air sea heat and momentum transfer are qualitatively discussed

rapid localization of pacific north america plate motion in the gulf of california correlation of late miocene volcaniclastic strata across the northern gulf of california shows that the pacific north america plate boundary localized east of the baja california peninsula ca 6 ma dextral offset of the 12 6 ma tuff of san felipe and a pair of overlying ca 6 3 ma pyroclastic flows indicate at least 255 10 km of displacement along an azimuth of 310 isopach and facies trends of the tuff of san felipe support no more than a few tens of kilometers of additional dextral displacement between 12 6 and 6 3 ma these constraints indicate that nearly all of the dextral displacement between the pacific and north american plates prior to 6 3 ma was accommodated outside of the gulf region and by 4 7 ma the plate boundary motion was localized in the gulf of california although continental extension has accounted for a component of plate boundary motion in northwestern mexico since cessation of subduction offshore of southern baja california at 12 5 ma transfer of baja california to the pacific plate was delayed by at least 6 7 m y

distinct influence of air sea interactions mediated by mesoscale sea surface temperature and surface current in the arabian sea abstractduring the southwest monsoons the arabian sea as develops highly energetic mesoscale variability associated with the somali current sc great whirl gw and cold filaments cf the resultant high amplitude anomalies and gradients of sea surface temperature sst and surface currents modify the wind stress triggering the so called mesoscale coupled feedbacks this study uses a high resolution regional coupled model with a novel coupling procedure that separates spatial scales of the air sea coupling to show that sst and surface currents are coupled to the atmosphere at distinct spatial scales exerting distinct dynamic influences the effect of mesoscale sst wind interaction is manifested most strongly in wind work and ekman pumping over the gw primarily affecting the position of gw and the separation latitude of the sc if this effect is suppressed enhanced wind work and a weakened ekman pumping dipole cause the gw to extend northeastward delaying the sc separation by 1 current wind i

main eddy vertical structures observed in the four major eastern boundary upwelling systems in the four major eastern boundary upwelling systems ebus mesoscale eddies are known to modulate the biological productivity and transport near coastal seawater properties toward the offshore ocean however little is known about their main characteristics and vertical structure this study combines 10 years of satellite altimetry data and argo float profiles of temperature and salinity and our main goals are i to describe the main surface characteristics of long lived eddies formed in each ebus and their evolution and ii to depict the main vertical structure of the eddy types that coexist in these regions a clustering analysis of the argo profiles surfacing within the long lived eddies of each ebus allows us to determine the proportion of surface and subsurface intensified eddies in each region and to describe their vertical structure in terms of temperature salinity and dynamic height anomalies in the peru chile upwelling system 55 of the sampled anticyclonic eddies aes have subsurface intensified maximum temperature and salinity anomalies below the seasonal pycnocline whereas 88 of the cyclonic eddies ces are surface intensified in the california upwelling system only 30 of the aes are subsurface intensified and all of the ces show maximum anomalies above the pycnocline in the canary upwelling system 40 of the aes and 60 of the ces are subsurface intensified with maximum anomalies extending down to 800 m depth finally the benguela upwelling system tends to generate 40 50 of weak surface intensified eddies and 50 60 of much stronger subsurface intensified eddies with a clear geographical distribution the mechanisms involved in the observed eddy vertical shapes are discussed

mixed layer instabilities and restratification abstract the restratification of the oceanic surface mixed layer that results from lateral gradients in the surface density field is studied the lateral gradients are shown to be unstable to ageostrophic baroclinic instabilities and slump from the horizontal to the vertical these instabilities which are referred to as mixed layer instabilities mlis differ from instabilities in the ocean interior because of the weak surface stratification spatial scales are o 1 10 km and growth time scales are on the order of a day linear stability analysis and fully nonlinear simulations are used to study mlis and their impact on mixed layer restratification the main result is that mlis are a leading order process in the ml heat budget acting to constantly restratify the surface ocean climate and regional ocean models do not resolve the scales associated with mlis and are likely to underestimate the rate of ml restratification and consequently suffer from a bias in sea surface temperatures and ml depths in a

arabian sea and bay of bengal exchange of salt and tracers in an ocean model exchanges of mass and salt between the mixed layers in the arabian sea and the bay of bengal are examined in a model of the indian ocean using passive tracers as a tool to map the pathways inflow of high salinity water from the arabian sea into the bay of bengal is significant and occurs after the mature phase of the southwest monsoon freshwater transport out of the bay of bengal is southward throughout the year along the eastern boundary of the indian ocean low salinity water transport into the arabian sea occurs in the somali current during the southwest monsoon closing a clockwise path of water mass transport only a small fraction of low salinity water is advected into the eastern arabian sea from the bay of bengal

seasonal mixed layer dynamics in an eddy resolving ocean circulation model 1 mean and seasonal mixed layer depths mlds derived from an eddy resolving ocean general circulation model with a horizontal resolution of 1 10 are validated with climatological observations associated heat budgets on seasonal timescales are analyzed for six boundary current regions with high eddy kinetic energy somali current agulhas current region kuroshio east australian current gulf stream and brazil malvinas falkland confluence in all of these regions and on seasonal timescales a horizontal advection significantly contributes to the mixed layer heat budget mlhb on eddy scales and locally exceeds 5 c month b lateral mixing calculated as a residual term is similar in size to surface net heat flux horizontal advection and vertical entrainment in defining the mixed layer temperature c seasonal vertical entrainment has a cooling effect on mixed layer temperature throughout the year in the regions investigated and d a phase lag between mld and changes in mixed layer heat content exists such that local cooling warming in the mixed layer precedes maxima minima in mld by 1 3 months a rather complex picture emerges where the mlhb in ocean boundary currents on larger spatial scales is determined by net surface heat fluxes and entrainment whereas local eddy related advection and stirring modulate the large scale signals

tectonic framework for late cretaceous to eocene quartz gold vein mineralization from the caborca orogenic gold belt in northwestern mexico

mesoscale eddies coastal upwelling and the upper ocean heat budget in the arabian sea estimation of the terms in the upper ocean heat budget from a moored array in the central arabian sea shows periods when a rough balance between the temperature trend and the horizontal advection of heat exists altimetry and sea surface temperature imagery are used to demonstrate that these episodes of strong horizontal advection are associated with mesoscale features during the wintertime northeast ne monsoon these are capped off mesoscale eddy features generated during the previous summertime southwest sw monsoon and have little horizontal transport of heat within the mixed layer during the sw monsoon the major contribution is strong offshore export of coastally upwelled water in a filament with a strong surface presence temperature and salinity properties from the moored array and a seasoar survey during the formation of the coastal filament confirm the offshore transport of the upwelled water mass to the site of the moored array more than 600 km offshore estimates of the filament section heat flux are several percent of the total estimated heat flux due to upwelling along the arabian peninsula and remote sensing data show that similar mesoscale variability along the coast is enhanced during the sw monsoon this points to the importance of mesoscale modulated transports in not only the observed heat budget at the moored array but in the overall upper ocean heat budget in the arabian sea

isopycnal mixing in ocean circulation models abstract a subgrid scale form for mesoscale eddy mixing on isopycnal surfaces is proposed for use in non eddy resolving ocean circulation models the mixing is applied in isopycnal coordinates to isopycnal layer thickness or inverse density gradient as well as to passive scalars temperature and salinity the transformation of these mixing forms to physical coordinates is also presented

seasonal variations in the upper arctic ocean as observed at t 3 hydrographic data from t 3 are analyzed to illustrate the behavior of the arctic mixed layer the mixed layer depth fluctuates 11 m annually and mixed layer salinity fluctuates 0 32 the fluctuations in total salt content are consistent with theoretical work by maykut and are in phase with mixed layer depth indicating changes in the mixed layer are controlled by salt flux deepening of the mixed layer brings 0 3 kcal cm 2 yr 1 of heat to the surface from the ocean below

the seasonal variation of the mixed layer and the pycnocline under polar sea ice a model of the seasonal variation of the mixed layer and the pycnocline under polar sea ice is compared with observations during the arctic ice dynamics joint experiment aidjex 1975 1976 the model is of the kraus turner type extended to include mixed layer and pycnocline the forcing mechanisms are the mechanical mixing due to ice keel stirring and the surface buoyancy flux due to melting and freezing of sea ice the model is designed to be used for climate studies in conjunction with atmospheric and oceanic general circulation models and with sea ice models

mesoscale eddies off peru in altimeter records identification algorithms and eddy spatio temporal patterns relatively little is known about coherent vortices in the eastern south pacific along the peruvian coast even with regard to basic facts about their frequency of occurrence longevity and structure this study addresses these issues with nearly 15 years of relatively high resolution satellite altimetry measurements we first compare two distinct automated methods for eddy identification the objective validation protocol shows that the rarely used geometrical or winding angle method based on the curvature of the streamline functions is more accurate than the commonly used okubo weiss algorithm which defines a vortex as a simple connected region with values of okubo weiss parameter weaker than a given threshold we then investigate vortices off peru using more than 20 000 mesoscale eddies identified by the winding angle method coherent eddies characterized by a high ratio of vorticity to deformation rate are typically formed along the coast and propagate westward at 3 6 cm s 1 the vortices have a mean radius of 80 km increasing northward and are most frequently observed off of chimbote 9s and south of san juan 15s the mean eddy lifetime is about 1 month but if eddies survive at least 2 months the probability for surviving an additional week or month is constant at 90 or 67 anticyclonic eddies tend to propagate northwestward whereas cyclonic vortices migrate southwestward in general cyclones and anticyclones are similar except for eddies surviving at least 6 months in this case after a similar 3 4 months of radius and amplitude growth amplitudes or sizes decay particularly rapidly for anticyclonic or cyclonic eddies in terms of intensity cyclonic eddies show a rapid decay during the first 3 months before arriving at a quasi constant value whereas anticyclones exhibit steady decline finally eddy temporal variations were examined at seasonal and interannual scales in the coastal region favorable to the formation of energetic mesoscale structures on seasonal scales eddy activity is maximal in fall and minimum in spring at interannual scales the eddy activity index was maximal during the strong el nino of 1997 1998 but another strong maximum of eddy activity also occurred late in 2004 these temporal variations are probably associated with the intensification of the upwelling thermal front and with the passage of coastal trapped waves which generate baroclinic instabilities further investigation of the mechanisms involved on the eddy genesis is needed

the role of salinity on the dynamics of the arabian sea mini warm pool warmer 28 c sea surface temperature sst occurs in the south eastern arabian sea seas 5 13 n 65 76 e during march april and is known as the arabian sea mini warm pool asmwp in this study we address the role of salinity and the upper layer heat and salt budgets in the formation and collapse of this asmwp an assessment of level 3 sea surface salinity sss data from the soil moisture and ocean salinity smos satellite mission for the year 2010 shows that smos is able to capture the sss variability in the seas analysis of temperature salinity and currents from the hybrid coordinate ocean model hycom during 2003 06 and in situ temperature and salinity data from argo floats during 2003 06 for the seas revealed that low salinity waters cap the top 60 m of the seas in january february this minimum salinity was concurrent with the formation of a barrier layer and with the time when the seas gained little net heat flux and the equatorward flowing east india coastal current eicc fed low saline waters into the seas subsequently the net heat flux increased to a peak value under the increased salinity stratification leading to the formation of the asmwp in march april the asmwp collapsed by may due to increase in sss and the associated weakening of the salinity stratification the monsoon onset vortex in may 2004 could be related to the minimum sss that occurred in february 2004 followed by higher sst and heat content of the asmwp in april 2004

pre miocene palaeogeography of the los cabos block baja california sur geochronological and palaeomagnetic constraints the los cabos block lcb is located at the southern end of the baja california peninsula and is composed mainly of intrusive rocks that were emplaced into pre cretaceous heterogeneous metasediments and are partly covered by miocene volcanic and volcaniclastic rocks field observations provide evidence that the undeformed homogeneous gabbronorite of the sierra el novillo in the ne part of the lcb is the oldest crystalline unit which is intruded by undeformed to slightly deformed tonalitic quartz dioritic granitoids for these rocks an rb sr intrusion age of 129 15 ma and a biotite whole rock cooling age of 116 2 ma were obtained low initial 87sr 86sr and high e nd values of about 0 7036 and 5t o 6 respectively characterise the intrusives as primitive mantle derived granites further to the southeast and south granitoids are more silicic with abundant deformed sequences orthogneisses diatexites and migmatites among others from the southern part of the lcb an rb sr intrusion age for the undeformed granites of 115 4 ma and a biotite cooling age of 90 2 ma were determined initial 87sr 86sr was determined to be 0 7054 and e nd values fall between 2 and 0 the isotopic data do not clearly allow us to characterise the deformed granitoids of the lcb as being intruded by the undeformed unit deformation could have been partly due to syn intrusive tectonics palaeomagnetic data suggest minor if any northward displacement of the lcb with respect to continental mexico corresponding to the rifting in the gulf of california since the late miocene and significant 35 45 clockwise rotations possible tilting evects which may have occurred given the dip of tertiary volcanics on top of the intrusives would modify these values for rotation and to a lesser degree of northward displacement geochemical isotopic and palaeomagnetic results and the cooling history of the lcb are similar to those from the puerto vallarta batholith whereas other mexican continental margin plutons further to the se display lower intrusion ages more rapid cooling rates and generally more primitive magma compositions in the light of the data presented a common magmatic evolution of the lcb and the puerto vallarta batholith is strongly suggested 2000 elsevier science b v all rights reserved

strong intraseasonal variability of meridional currents near 5 n in the eastern indian ocean characteristics and causes abstractthis paper reports on strong intraseasonal upper ocean meridional currents observed in the indian ocean between the bay of bengal bob and the equator and elucidates the underlying physical processes responsible for them in situ measurements from a subsurface mooring at 5 n 90 5 e reveal strong intraseasonal variability of the meridional current with an amplitude of 0 4 m s 1 and a typical period of 30 50 days in the upper 150 m which by far exceeds the magnitudes of the mean flow and seasonal cycle such prominent intraseasonal variability is however not seen in zonal current at the same location further analysis suggests that the observed intraseasonal flows are closely associated with westward propagating eddylike sea surface height anomalies sshas along 5 n the eddylike sshas are largely manifestations of symmetric rossby waves which result primarily from intraseasonal wind stress forcing in the equatorial waveguide and reflection of the equatorial kelvin waves at the eastern bou

the impact of ocean surface currents on sverdrup transport in the midlatitude north pacific via the wind stress formulation abstracta more complete wind stress n formulation takes into account the ocean surface currents vo while the conventional wind stress c popularly used in ocean circulation models is only a function of 10 m winds v10 an analytical solution is derived for the difference of sverdrup transport induced by using n instead of c a scaling analysis of the analytical solution indicates a 6 reduction of the sverdrup transport in the north pacific i e the kuroshio transport in the east china sea when ekman velocity dominates the ocean surface currents because of the quadratic nature of wind stress four nonlinear terms contribute equally to this difference two vorticity torque terms and two speed gradient torque terms a pair of 12 5 yr july 2002 14 hybrid coordinate ocean model simulations that only differ in the wind stress formulation are used to test the analytical solution the model results 2004 14 confirm that using n instead of c reduces the sverdrup transport in the north pacific by 8 17