pacific equatorial subsurface countercurrent velocity transport and potential vorticity concurrent shipboard adcp and ctd sections are used to calculate the mean velocity transport and potential vorticity fields associated with the pacific equatorial subsurface countercurrents sccs averaged in stream coordinates the core eastward velocity of the sccs is a factor of 2 higher than previously reported means but the estimated transports are unchanged the meridional profile of zonal velocity along isopycnals is sharply peaked and nearly linear on each flank of the current the sharp and strong reversal of relative vorticity over a distance of 20 km at the jet core sharpens the coincident potential vorticity front this front separates a region of very low homogeneous potential vorticity on the equatorward side from a homogeneous high potential vorticity region on the poleward side each potential vorticity pool extends well beyond the edges of the scc into regions of westward flow on the equatorward sides of the sccs this westward flow is the equatorial intermediate current in the western pacific but in the central and eastern parts of the basin it is off the equator in deep extensions of the south equatorial current in the central and eastern regions the net westward transport in an isopycnal layer between the sccs exceeds the combined eastward scc transport in that layer the net zonal transport between the scc cores is highly divergent in the east and convergent in the west this pattern together with downstream changes in scc density indicates that neither they nor the westward return flows are simple inertial recirculations strong diapycnal processes must be involved

petrography and genesis of spicular and columnar geyserite from the whakarewarewa and orakeikorako geothermal areas north island new zealand domal masses of geyserite which surround many geyser vents in the whakarewarewa geothermal area are formed largely of spicules spicule columns and shrub columns the non branching spicules and the branches of branching spicules individually up to 3 cm high and 1 mm diameter have a laminated core encased by siliceous cortex silicified microbes are rare in the core but common in the cortex silicified microbial mats and pseudodendrites are found in the crevices between neighbouring spicules shrub columns up to 5 cm high and 1 5 cm in diameter are formed of opal a that was precipitated around a three dimensional branching shrub like microbial structure the shrub branches which are hollow with scalloped walls do not contain any evidence of the original microbes or minerals that formed them silicified microbial mats are present between the columns microbial boring and etching by acidic steam led to local diagenetic degradation of these columns in the geyserite mounds at whakarewarewa spicules and spicule columns are common whereas shrub columns are rare interbedding and intercalation of spicular geyserite with shrub columnar geyserite indicate however that these different morphologic entities probably formed under similar environmental conditions on the mounds around the geyser vents petrographic evidence shows that the spicules spicule columns and shrub columns grew through a combination of biotic and abiotic processes

postcyclic recompression stiffness and consolidated cyclic strength of silt low plasticity silts are liquefiable and the dissipation of pore pressures after an earthquake will be accompanied by densification and compression of the soil skeleton anisotropic rather than isotropic stress distributions are commonly found to exist in slopes or silty fills placed under k0 conditions and this can be enhanced further by the weight of overlying structures compression after an earthquake generally increases soil resistance but it can still be liquefied by aftershocks the postcyclic recompression of silt and postdrainage monotonic and cyclic strength and stiffness have therefore been investigated with respect to the effect of initial anisotropic consolidation the compressibilities during postcyclic recompression were similar to those for isotropic consolidation samples with a greater initial anisotropy had less volumetric strain but larger axial strains during postcyclic drainage under stress reversal conditions failure occurred as a result of the development of double amplitude cycl

interannual variability of surface currents in the tropical pacific during 1987 1993 buoy drifts and current meter records between january 1987 and december 1993 are used to investigate the interannual variability of the equatorial pacific currents at a depth of 15 m the sampling is coarse until mid 1988 but more complete afterward so that the large scale features of the anomaly currents can be documented on the seasonal to yearly timescale using objective analysis bimonthly current anomalies are mapped between 20 n and 20 s on a 1 5 grid and the error covariance matrix of the analyzed fields are estimated the current anomalies are primarily zonal with largest amplitudes within about 8 from the equator and they are largely linked to the el nino southern oscillation phenomenon in particular broad basin wide westward anomaly currents were encountered during the 1988 la nina and strong eastward currents persisted from july august 1991 to january february 1992 followed by westward currents from may june to july august 1992 an empirical orthogonal function eof analysis shows that the first eof of zonal current anomaly is largely uniform in the equatorial band while the next two eofs describe large scale currents of opposite sign across the equator and across 160 w respectively the eofs are rather smooth and the errors on the principal component time series relatively small which indicates that the sampling is adequate to describe the large scale low frequency zonal current fluctuations as the dominant eofs of meridional current are noisy and the relative errors on the principal components larger the meridional current fluctuations are not as well captured by the data set correlation analysis and a singular value decomposition are used to investigate the influence of advection by the large scale low frequency currents on sea surface temperature sst anomalies during 1987 1993 although the data set is noisy and other terms play an important role in the sst anomaly equation the effect of zonal and to a lesser extent meridional advection is seen in much of the central and eastern equatorial pacific the dominant terms are the anomalous zonal advection of mean sst the mean zonal and intermittently meridional advection of sst anomalies

observations of annual and el nino thermal and flow variations at 0 110 w and 0 95 w during 1980 1985 moored measurements of the surface wind and of the current and temperature fields within the uppermost 250 m were recorded from march 1980 to september 1985 at 0 110 w and from july 1981 to november 1983 at 0 95 w at these sites the annual mean thicknesses of the equatorial undercurrent euc and of the surface portion of the south equatorial current sec were about 200 m and 20 m respectively the annual mean euc core speed was 0 9 m s 1 annual cycles of temperature and zonal current at 110 w were most distinctive near the surface at nominal depths of 15 m and 47 5 m the average annual amplitudes were 1 5 c and 0 5 m s 1 at about 100 m the annual amplitudes were about 0 5 c and 0 10 m s 1 at 15 m the annual mean zonal current was 0 05 m s 1 which was not representative of the monthly mean zonal current in april the monthly mean direction was eastward and in october it was westward with speeds of about 0 5 m s 1 in both months warmer water occurred in april and colder water in october the direction of the zonal wind component was westward throughout the year and the annual amplitude of the zonal wind was only about 2 5 times larger than that of the zonal current the average amplitude of the annual cycle of the meridional current component was less than 0 05 m s 1 and not distinguishable from year to year monthly mean variations monthly mean anomalous or el nino currents at 110 w were defined as the difference between the observations and the annual cycle during the august december 1982 onset phase of el nino the strength of the normally westward flowing near surface sec was greatly reduced to near zero speed by an el nino eastward flowing zonal current of about 0 3 m s 1 the largest vertically averaged 15 250 m zonal current anomaly 0 5 m s 1 occurred in january and february 1983 and represented a substantial decrease in the eastward transport of the euc causing a disappearance of the undercurrent the duration of the euc disappearance was longer at 95 w than at 110 w a surface intensified eastward jet with a maximum daily speed of 1 75 m s 1 at 15 m occurred in may 1983 at 110 w but not at 95 w a massive redistribution of heat throughout the mixed layer and thermocline was associated with the 1982 1983 el nino beginning in august 1982 the thermocline at 110 w and 95 w sank 100 m reaching its maximum depth in december 1982 temperatures at 100 m and 150 m which normally were about 15 c and 14 c reached 27 5 c and 22 5 c the time rate of change of the 15 to 200 m heat content was 500 w m 2 during the august december 1982 warming phase and 460 w m 2 during the january february 1983 subsurface cooling phase the euc disappeared during the subsurface cooling phase a second less intensive mixed layer deepening occurred in may 1983 at 95 w but not at 110 w

eastern pacific ocean circulation near the onset of the 1982 1983 el nino over a 1 month period october 5 to november 6 1982 during the initial stages of the 1982 1983 el nino hydrographic and velocity profiling measurements were made in the eastern equatorial pacific by two research vessels track lines approximated a square centered near the galapagos islands with approximately meridional sections at 95 w and 85 w and nearly zonal sections at about 5 n and 5 s water mass characteristics and estimated currents of these sections are discussed sea surface temperature nearly everywhere was warmer than 25 c an anomaly of 2 c 3 c the equatorial thermocline represented by the 20 c isotherm was depressed by nearly 50 m at 85 w and more than 100 m at 95 w relative to a historical mean profile across 95 w estimated geostrophic relative to 500 dbar and directly measured near equatorial velocity profiles indicated significant eastward surface flow the south equatorial current south of the equator had disappeared estimated warm water transport t 24 5 kg m 3 indicated an influx into the region which was approximately that required to balance the observed low frequency sea level change at the galapagos islands temperature and salinity properties as well as the transport estimates indicated that this warm water came predominantly from the west

antarctic circumpolar waves an indication of ocean atmosphere coupling in the extratropics recent observational studies have detected coherent oceanic and atmospheric antarctic circumpolar waves acws which propagate eastward at speeds of 6 8 cm s 1 with a circumpolar wavenumber of 2 analysis of global wind data suggests that the acws are not remotely forced by tropical el nino activity through atmospheric teleconnection rather a coupled instability of the antarctic circumpolar current and its overlying atmospheric motion is proposed to be responsible for the generation of the acws the phase relationship among the observed oceanic and atmospheric variables supports the coupled instability theory this study provides one clear example that extratropical ocean atmosphere dynamical coupling is essential in generating climate variations on time scales of several years and longer

relative influences of the interdecadal pacific oscillation and enso on the south pacific convergence zone 1 the south pacific convergence zone spcz one of the most extensive features of the global atmospheric circulation is shown to vary its location according to both the polarity of the el nino southern oscillation enso and of the interdecadal pacific oscillation ipo we first demonstrate that the ipo can be regarded as the quasi symmetric pacific wide manifestation of the pacific decadal oscillation that has been described for the north pacific shifts in the position of the spcz related to enso on interannual time scales and to the ipo on decadal time scales appear to be of similar magnitude and are largely linearly independent a station pressure based index of variations in spcz latitude is shown to be significantly related to the polarity of the ipo when enso influences are accounted for movements of this sensitive section of the spcz have occurred in phase with those of the ipo since the 1890s

cyclic behaviour of reconstituted and desiccated rewet thickened gold tailings in simple shear a simple shear apparatus norwegian geotechnical institute ngi type has been used to investigate the mechanical behaviour of gold tailings under monotonic cyclic and post cyclic loading specimens were prepared either by reconstituting the tailings at different water contents or by employing a dry wet preparation technique the latter technique attempted to simulate a realistic stress history for thickened tailings deposition by preparing the specimen at the pumping water content and subsequently allowing it to settle and then desiccate to a target water content subsequently these specimens are rewetted and then consolidated cyclic resistance ratios for specimens prepared by the dry wet preparation technique were considerably higher than those of specimens prepared by the standard technique though there appears to be no advantage in drying the tailings past the shrinkage limit in general the tailings could experience significant deformation during cyclic and post cyclic loading irrespective

observations of warm water volume changes in the equatorial pacific and their relationship to el nino and la nina abstract this paper describes observed changes in surface winds sea surface temperature sst and the volume of water warmer than 20 c wwv in the equatorial pacific ocean for the period 1980 99 the purpose is to test recent hypotheses about the relationship between variations in wwv and the el nino southern oscillation enso cycle the results confirm inferences based on theory models and previous empirical analyses using proxy data namely sea level that enso involves a recharge and discharge of wwv along the equator and that the cyclic nature of enso results from a disequilibrium between zonal winds and zonal mean thermocline depth the authors also find that the magnitude of enso sst anomalies is directly related to the magnitude of zonal mean wwv anomalies furthermore for a given change in equatorial wwv the corresponding warm el nino sst anomalies are larger than the corresponding cold la nina anomalies this asymmetry between the warm and cold phases of the enso cycle implies differences

benefits of cmip5 multimodel ensemble in reconstructing historical ocean subsurface temperature variations abstracta complete map of the ocean subsurface temperature is essential for monitoring aspects of climate change such as the ocean heat content ohc and sea level changes and for understanding the dynamics of the ocean climate variation however global observations have not been available in the past so a mapping strategy is required to fill the data gaps in this study an advanced mapping method is proposed to reconstruct the historical ocean subsurface 0 700 m temperature field from 1940 to 2014 by using ensemble optimal interpolation with a dynamic ensemble enoi de approach and a multimodel ensemble of phase 5 of the coupled model intercomparison project cmip5 historical and representative concentration pathway 4 5 simulations the reconstructed field is a combination of two parts a first guess provided by the ensemble mean of cmip5 models and an adjustment by minimizing the analysis error with the assistance of error covariance determined by the cmip5 models the uncertainty of the field ca

variability in the western equatorial pacific ocean during the 1986 87 el nino southern oscillation event abstract we describe variability in the western pacific ocean during the 1986 87 el nino southern oscillation enso event with emphasis on time series measurements of currents temperature sea level and winds near the equator at 165 e zonal winds were anomalously westerly from mid 1986 to late 1987 and were punctuated by 2 10 m s 1 episodes of westerlies lasting about 10 days to 2 months zonal current in the upper 100 m surface layer responded to these wind variations typically within a week in some cases with speeds exceeding 100 cm s 1 to the east zonal current variations in the thermocline below 100 m were generally less coherent with the local wires than currents near the surface they were also generally less variable although the equation undercurrent disappeared for 3 4 weeks in october november 1987 at a time when the normal eastward directed zonal pressure gradient force reversed along the equator periods of intense and prolonged eastward flow in the surface layer were associated with a

the north equatorial countercurrent and heat storage in the western pacific ocean during 1982 83 a sequence of extreme climate anomalies known as an el nino southern oscillation episode was observed in the tropical pacific ocean during 1982 831 2 models suggest that oceanic circulation has an important role in the formation of such anomalies1 3 4 by altering the pattern of sea surface temperature through advection the baroclinic structure of the upper 500 m of the ocean has been monitored routinely in the western pacific since 1979 providing indirect current measurements by the geostrophic method these observations reported here show large changes in the near equatorial currents during 1982 83 which are consistent with currents observed in the central and eastern pacific5 6 in particular the north equatorial countercurrent necc flowed with 25 50 increased strength during the early phase then weakened almost to zero flow the west pacific heat pool cooled by more than 1 c observed changes in circulation were large enough to alter surface heat storage by advection although other potentially important processes may not be negligible

equatorial undercurrent disappears during 1982 1983 el nino the equatorial undercurrent at 159 w decayed during august 1982 partially reversed during september and rapidly reappeared in january 1983 the virtual disappearance is consistent with the basin wide adjustment of sea surface slope to the strong westerly winds in the western and central pacific that caused the 1982 1983 el nino event

hydrographic variability west of the galapagos islands during the 1982 1983 el nino abstract nine hydrographic temperature salinity and in some cases oxygen and four zonal velocity sections near the equator along 95 w in 1980 1984 are presented and discussed perturbations associated with the 1982 1983 el nino form the locus for the discussion this event was sampled by sections in november 1982 and in march may november and december 1983 the upper ocean response in november 1982 was a downward displacement of isotherms above 400m on the equator the equatorial undercurrent euc was deep and strong for this season the vertical displacement perturbations extended to at least 5 s and were more uniform with depth off the equator in may 1983 the largest vertical displacements were observed the euc was replaced by a westward jet at about 75m and the equatorial 13 c water thermostad has disappeared local estimates of the zonal pressure gradient suggest that between 110 w and 95 w this slope had reversed in may 1983 and was at least in part responsible for the observed westward jet local winds were westerly and forced the observed eastward surface current by november 1983 surface conditions were fairly normal however the deeper stratification remained anomalous the equatorial 13 c water thermostad was still missing the vertical profile of vertical displacements from a mean suggested a complicated vertical structure near the equator in april 1984 conditions had returned to near normal

variations of zonal currents in the central tropical pacific during 1970 to 1987 sea level and dynamic height measurements the annual and interannual variations of the major zonal currents of the central tropical pacific for the period 1970 1987 are described by analyzing two data sets sea level data from a few selected island stations and ship of opportunity expendable bathythermograph xbt observations the annual cycles of geostrophic surface current indices dynamic height or sea level difference between the ridge and the trough defining the current in the north equatorial current nec and north equatorial countercurrent necc are found to be in phase maxima in november to be strong and to explain about 50 of the total variance the annual cycle of volume transport relative to 400 dbar in the necc is also strong but nec volume transport has a weak annual cycle the discrepancy between the nec surface current and the transport is due to the variation of the surface current being larger than that of the deep currents the annual cycle of the transport of the south equatorial current sec is 6 months out of phase with that of the nec and necc phases of the annual cycles of the sea level and dynamic height indices of flow agree well in general but there are significant differences between the annual amplitudes of the two types of measurements these differences arise from a variety of sources dynamic height reference level assumptions longitudinal spacing of sea level gauges meridional resolution of sea level array and different signal to noise ratios for the two sets of indices the necc shows marked flow maxima during the peaks of the strong ninos of 1972 and 1982 which were followed by near disappearance of the current the following year these fluctuations are clearly present in both the surface current indices and the volume transport in 1976 and 1986 1987 moderate ninos the same pattern is not marked the el nino signal in nec transport is weak there was a strong rise of equatorial sea level during the early phases of the 1972 and 1982 ninos followed by a fall the next year this resulted in a decrease of the transport of the sec in the first year followed by an increase to a maximum during the second year the maximum coincides with a minimum in necc transport

the three dimensional structure of an upper ocean vortex in the tropical pacific ocean in the equatorial pacific ocean easterly trade winds and the earth s rotation combine to drive surface currents away from the equator thereby causing cold nutrient rich subsurface water to upwell the front1 that forms between this upwelled water and warmer waters north of the equator is sometimes visible as a spectacular line in the sea 2 between 2 and 6 n westward propagating cusp shaped disturbances observed along this front3 have been attributed to the effect of dynamical instabilities in the system of zonal equatorial currents4 11but the connection between these phenomena remains unclear here we report extensive measurements from shipboard sensors satellite and drifting buoys which reveal the three dimensional structure of an anticyclonic eddy or vortex 500 km in diameter and centred at 4 n we suggest that cusp shaped disturbances of the front are caused by trains of large amplitude vortices which are driven by instability of the mean zonal shear we show that these vortices not only play an important role in the meridional transport of heat salt and momentum but are also associated with regions of intense horizontal convergence along the front where dramatic concentrations of marine life are observed

the liquefaction of sands a collapse surface approach recent large scale slides occurring during the hydraulic placement of an artificial island berm in the beaufort sea resulted from the liquefaction of the berm sand subsequent laboratory tests and

recent hiatus caused by decadal shift in indo pacific heating recent modeling studies have proposed different scenarios to explain the slowdown in surface temperature warming in the most recent decade some of these studies seem to support the idea of internal variability and or rearrangement of heat between the surface and the ocean interior others suggest that radiative forcing might also play a role our examination of observational data over the past two decades shows some significant differences when compared to model results from reanalyses and provides the most definitive explanation of how the heat was redistributed we find that cooling in the top 100 meter layer of the pacific ocean was mainly compensated for by warming in the 100 to 300 meter layer of the indian and pacific oceans in the past decade since 2003

upper equatorial pacific ocean current and salinity variability during the 1996 1998 el nino la nina cycle the recent el nino la nina cycle exhibited striking patterns of current and salinity variability in the upper equatorial pacific ocean this evolution is described from mid 1996 through 1998 using a remarkable data set of 35 meridional conductivity temperature depth ctd acoustic doppler current profiler adcp sections along with buoy data the sections nominally from 8 s to 8 n between 165 e and 95 w were occupied over the course of 27 months a wide range of current variability was sampled with currents that appeared or disappeared some time during the cycle including an equatorially trapped eastward surface current the equatorial undercurrent the northern branch of the south equatorial current and the north equatorial countercurrent basin wide interannual changes in upper ocean and pycnocline zonal transports were as large as 64 32 106 m3 s 1 changes in the salinity structure included a deep and fresh mixed layer in the central equatorial pacific that built up during the el nino and was then disrupted by upwelled salty water with the onset of la nina a very fresh mixed layer observed in the eastern equatorial pacific late in the el nino and a reduction in the strength of the meridional equatorial salinity gradient within the pycnocline to one third of the usual value during the el nino finally the zonal transports above the thermocline from 5 s to 5 n were well correlated with the rate of change of warm water volume west of the individual ctd adcp sections

the california current system in relation to the northeast pacific ocean circulation abstract the california current system is described in its regional setting using two modern datasets argo provides a broadscale view of the entire eastern north pacific ocean for the period 2004 2010 and the high resolution xbt network includes transects from honolulu to san francisco 1991 2010 and to los angeles 2008 2010 together these datasets describe a california current of 500 800 km width extending along the coast from 43 n to 23 n the mean southward transport of the california current is about 5 sv off central and southern california with about 2 5 sv of northward flow on its inshore side interannual variations are 50 or more of the mean transports the salinity minimum in the core of the california current is supplied by the north pacific current and by freshwater from the northern continental shelf and modified by alongshore geostrophic and across shore ekman advection as well as eddy fluxes and air sea exchange the heat and freshwater content of the california current vary in response to the fluctuating strength of the alongshore geostrophic flow on its offshore side the california current is influenced by north pacific intermediate waters at its deepest levels and by eastern subtropical mode waters on shallower density surfaces in total the sources of the california current its alongshore advection and its strong interactions with the inshore upwelling region and the offshore gyre interior combine to make this a rich and diverse ecosystem the present work reviews previous contributions to the regional oceanography and uses the new datasets to paint a spatially and temporally more comprehensive description than was possible previously

estimating global ocean heat content changes in the upper 1800 m since 1950 and the influence of climatology choice abstractocean heat content anomalies are analyzed from 1950 to 2011 in five distinct depth layers 0 100 100 300 300 700 700 900 and 900 1800 m these layers correspond to historic increases in common maximum sampling depths of ocean temperature measurements with time as different instruments mechanical bathythermograph mbt shallow expendable bathythermograph xbt deep xbt early sometimes shallower argo profiling floats and recent argo floats capable of worldwide sampling to 2000 m have come into widespread use this vertical separation of maps allows computation of annual ocean heat content anomalies and their sampling uncertainties back to 1950 while taking account of in situ sampling advances and changing sampling patterns the 0 100 m layer is measured over 50 of the globe annually starting in 1956 the 100 300 m layer starting in 1967 the 300 700 m layer starting in 1983 and the deepest two layers considered here starting in 2003 and 2004 during the implementation of argo furthermor

on the relationship between tropical and north pacific sea surface temperature variations abstract empirical orthogonal function analysis of winter sea surface temperature sst anomalies over the pacific domain 60 n 20 s reveals an el nino southern oscillation enso mode that is linked to the eastern north pacific and a north pacific mode that is linearly independent of enso the north pacific mode exhibits maximum amplitude and variance explained along 40 n west of 170 w ssts in this region have decreased by 1 5 c from 1950 to 1987 the cooling in winter has been associated with a strengthening of the overlying westerly winds

undisturbed sampling of saturated sands by freezing from considerations of the basic mechanisms of soil behavior during freezing it is suggested that undisturbed samples can only be obtained by undirectional freezing with no impedance of drainage while the confining pressure is maintained experimental data illustrate that this method can lead to laboratory samples which maintain their in situ characteristics care is required to ensure the effectiveness of the method and it is noted that variables such as the coolant temperature the percentage of fines in the sand and the depth of sampling can influence the efficiency and effectiveness of the method it is shown that the beneficial effects of freezing samples by surrounding the sampling tube with dry ice prior to shipping can only be achieved if the samples are drained prior to freezing if a sample contains a large percentage of fines insufficient drainage may cause all around freezing to have deleterious effects on the quality of the sample

biologically mediated dissolution of volcanic glass in seawater we studied the effects of biological mediation on the dissolution of basaltic glass in seawater experiments with typical seawater microbial populations were contrasted with a sterile control and reactions were monitored chemically and isotopically biologically mediated experiments produce twice the mass of authigenic phases than abiotic experiments and the phases are different abiotic alteration of glass dissolves basaltic si and ca and scavenges seawater mg while biotic alteration removes ca from seawater such opposing behavior of ca and mg in biotic and abiotic alteration of basaltic glass may have important implications for the carbon cycle and the exchange processes between ocean crust and seawater 87sr 86sr data of glass and alteration products suggest that biological mediation enhances both the diffusion of seawater sr into glass by a factor of 3 4 and the dissolution of basaltic sr into seawater by a factor of 20 40 the dependence of chemical exchange processes between seawater and glass on biological activity implies that chemical fluxes from water rock interaction at low temperatures may change as life on earth evolves

observations of horizontal velocities and vertical displacements in the equatorial pacific ocean associated with the early stages of the 1982 83 el nino abstract pacific near equatorial absolute velocity data and ctd o2 observations collected from the r v conrad in the northern fall of 1982 are presented quite by chance the cruise took place during the early stages of the 1982 83 el nino the data obtained are generally consistent with the fundamental ideas about el nino onset in that abnormal eastward flow near the surface and large thermocline depressions were observed these changes are quantified by comparing with previously collected data and are discussed in terms of simple equatorially trapped wave dynamics the results indicate that first and second mode disturbances probably kelvin waves were prominent in the equatorial pacific in the fall of 1982

correlation analyses between sea surface temperature anomalies in the eastern equatorial pacific and the world ocean based on data from the comprehensive ocean atmosphere data set coads objective analyses of the monthly mean sea surface temperature sst were prepared at gfdl for each month of the 110 year period 1870 1979 time series of various indices characterizing the sst anomalies averaged over the eastern equatorial pacific eep the tropical oceans and the world ocean are presented for monthly yearly and decadal time averaging periods global correlations maps are given for each decade of the 1870 1979 period they show the spatial connections between the monthly sst anomalies in the eep and in other parts of the world ocean and how these connections vary for the different decades on the intermonthly time scale the sst anomalies in the eep and those in the tropical and world oceans are found to be highly correlated with maximum correlations values of 0 91 at zero lag for the tropical oceans during the 1950 1959 decade and 0 81 for the world ocean during the 1970 1979 decade positive correlation values of r 0 36 persist on average from about 4 months before to about 8 months after the eep anomalies occur there is a clear tendency for the tropical and world ocean anomalies to lag behind the eep anomalies comparing different oceans we find the tendency for the tropical sst anomalies in the indian and atlantic oceans to lag behind those in the eep region by about 1 and 3 months respectively on the interannual time scale the eep anomalies are also well correlated with those in the other regions having an average correlation of 0 84 for the tropical oceans and of about 0 7 for the world ocean

variability in the eastern equatorial pacific ocean during 1986 1988 we examine variability in the eastern equatorial pacific during 1986 1988 using conductivity temperature depth data velocity and temperature data from equatorial moorings between 110 w and 140 w and wind data from a basin scale zonal array of islands and moorings between 110 w and 165 e the period studied coincides with the el nino southern oscillation enso event of 1986 1987 and a subsequent cold event in 1988 weak warm sea surface temperature anomalies first appeared in the eastern equatorial pacific in mid 1986 and increased to 1 c in september november 1986 in association with a 30 cm s 1 weakening of the south equatorial current and a 20 to 40 m depression of the thermocline these warm anomalies lasted until early 1988 after which a large scale shoaling of the thermocline led to sea surface temperatures more than 3 c colder than climatology year to year fluctuations in the eastern pacific were related primarily to zonal wind variations in the central and western pacific westerly wind stress anomalies of 0 02 0 05 n m 2 were observed between 140 w and 165 e from the latter half of 1986 until the end of 1987 these were replaced by easterly wind anomalies of similar magnitude between 157 w and 165 e in 1988 energetic intraseasonal fluctuations with periods of 2 3 months were also prominent in zonal current temperature and dynamic height time series these fluctuations propagate eastward at approximately first baroclinic mode kelvin wave phase speeds and are forced west of the date line by episodes of westerly winds extrema in several oceanic variables occurred in association with these waves though their precise dynamical link to the enso cycle is unclear from our data sea surface temperature and thermocline depth anomalies at 0 110 w were less pronounced during the 1986 87 enso than during the 1982 1983 enso the equatorial undercurrent though weaker than normal in early 1987 did not disappear as it did in early 1983

as el nino builds pacific warm pool expands ocean gains more heat el nino southern oscillation enso effects substantial redistributions of ocean temperature both horizontal and vertical on interannual time scales especially in the pacific ocean analyses of monthly argo based ocean temperature maps illustrate large scale ocean heat content redistributions with enso they quantify a globally averaged sea surface temperature warming of 0 1 c with a 1 c increase of the nino3 4 index a moderate el nino a substantial perturbation to the 0 13 c decade 1 trend in sea surface temperature monthly satellite based estimates of earth s energy imbalance suggest that a 1 c increase of the nino3 4 index corresponds to an increase of 3 4 zj in earth s energy storage more gently modulating the longer term 114 zj decade 1 trend yearly global ocean heat content estimates based on ocean temperature data with their reduced uncertainties compared to monthly maps reveal interannual variations in earth s energy storage that correspond well with satellite based estimates

effect of initial consolidation condition on postcyclic undrained monotonic shear behavior of mississippi river valley silt abstractthe postcyclic undrained monotonic shear behavior of mississippi river valley mrv silt is investigated by carrying out triaxial tests under various initial consolidation conditions results show that the variation of cyclic shear strength of mrv silt against initial overconsolidation ratio ocr and mean effective consolidation pressure c was consistent with previous studies i e it increased with both increase in ocr and decrease in c the cyclic stress ratio csr had no apparent effect on postcyclic shear behavior for mrv silt at higher ocrs the postcyclic reconsolidation behavior was more similar to recompression unlike the specimens not previously subjected to cyclic loading the initial ocr did not influence effective stress path of the postcyclic reconsolidated specimens at the early stages of shearing the normalized undrained shear strength su oc su nc of mrv silt reconsolidated after cyclic loading increased with ocr stress strain curves of mrv silt reconsolidated after c

the global ocean imprint of enso 1 the enso related spatial patterns and global averages of ocean temperature salinity and steric height are estimated from over 7 years of argo data 2004 2011 substantial extratropical variability is seen in all variables in addition to familiar tropical enso signals surface layer 0 100 dbar and subsurface 100 500 dbar temperature variations are both important in determining steric height and sea surface height patterns for the two years prior to the 2009 el nino the upper 100 dbar of the ocean gained 3 3 1022 j yr 1 of heat while the 100 500 dbar layer lost a similar amount the enso related vertical redistribution of globally averaged heat content between surface and subsurface layers occurring throughout the record is due primarily to changes in the east west tilting of the equatorial pacific thermocline the large temperature changes in the individual layers mask the smaller vertically averaged temperature change in which the ocean loses heat when the surface layer is anomalously warm and gains heat when the surface layer is cool

el nino modoki and its possible teleconnection 1 using observed data sets mainly for the period 1979 2005 we find that anomalous warming events different from conventional el nino events occur in the central equatorial pacific this unique warming in the central equatorial pacific associated with a horseshoe pattern is flanked by a colder sea surface temperature anomaly ssta on both sides along the equator empirical orthogonal function eof analysis of monthly tropical pacific ssta shows that these events are represented by the second mode that explains 12 of the variance since a majority of such events are not part of el nino evolution the phenomenon is named as el nino modoki pseudo el nino modoki is a classical japanese word which means a similar but different thing the el nino modoki involves ocean atmosphere coupled processes which include a unique tripolar sea level pressure pattern during the evolution analogous to the southern oscillation in the case of el nino hence the total entity is named as el nino southern oscillation enso modoki the enso modoki events significantly influence the temperature and precipitation over many parts of the globe depending on the season the impacts over regions such as the far east including japan new zealand western coast of united states etc are opposite to those of the conventional enso the difference maps between the two periods of 1979 2004 and 1958 1978 for various oceanic atmospheric variables suggest that the recent weakening of equatorial easterlies related to weakened zonal sea surface temperature gradient led to more flattening of the thermocline this appears to be a cause of more frequent and persistent occurrence of the enso modoki event during recent decades

equatorial pacific thermostad response to el nino el ninos are characterized by a shift of warm surface water from the western to eastern equatorial pacific due to weakening of easterly trade winds this shift is associated with the pycnocline or thermocline the large vertical density gradient beneath the surface mixed layer shoaling in the west and deepening in the east inducing a redistribution of ocean heat with global impacts here the response of the pacific equatorial thermostad a layer of low vertical stratification below the pycnocline to el nino is investigated using a monthly argo float climatology and argo float deep velocity data a mean seasonal cycle trend and time lagged linear response to the nino3 4 index are fit by least squares to temperature and salinity at each gridpoint as well as to deep float velocities omitting the trend the results of these fits are used to characterize the response of physical properties in the thermostad including layer thickness and velocity to el nino by comparing the mean properties following neutral conditions nino3 4 0 c versus those following a moderate el nino nino3 4 1 c following an el nino a strengthening of the westward flowing equatorial intermediate current of about 2 7 106 m3 s 1 shifts about 97 1012 m3 of thermostad water from the east to the west allowing conservation of volume within the thermostad as the pycnocline above deepens in the east and shoals in the west this transport and volume change imply a 14 month time scale consistent with el nino this article is protected by copyright all rights reserved

the geological significance of endolithic algae in glass calcified filaments of ostreobium are common in beachrock on grand cayman island the alga exhibits an epilithic chasmolithic and endolithic mode of life in its endolithic mode it bores into carbonate allochems and apparently uses the mg and ca so derived in calcifying the filament in its epilithic or chasmolithic mode glass fragments cemented in the beachrock are also bored by algae in a manner similar to the carbonate allochems the si dissolved by the alga in its boring phase is incorporated along with ca and cl in the algal sheath the fact that algae can bore into glass suggests that they do not assume an endolithic life mode in order to obtain organic nutrients or moisture the algae assume this life habit because of external pressures such as wave energy or simply because the algae bore into any available substrate this example also demonstrates that algae are capable of secreting substances that can dissolve silica

bioalteration of basaltic glass in the oceanic crust 1 bioalteration of quaternary to early cretaceous basaltic glass from pillow lavas of the upper oceanic crust can be documented in deep sea drilling project ocean drilling program dsdp odp samples from shallow to deep drill holes from the north to central atlantic ocean lau basin and costa rica rift a wide range of marine settings biogenerated textures are rooted in fractures and occur as two main types a granular type and a tubular type the granular type common at all depths within the volcanic pile appears as solid bands semicircles or irregular patches of individual and or coalesced spherical bodies mostly 0 2 0 6 m in diameter with irregular protrusions into the fresh glass the tubular type is more common at deeper levels in the crust and consists of thin tubes sometime branching bodies mostly 20 30 m long and are more common at deeper levels the upper crust displays a large variability in the relative importance of biotic to abiotic alteration and the degree of bioalteration appears to decrease with depth thus the fraction of bioalteration of the total alteration of the glass ranges from 20 90 in the upper 300 m down to a maximum of 10 at about 500 m depth this might be due to a natural variability in the abundance of bioaltered glass or to biased sampling from low drilling recovery of relatively young crust the proportion of bioaltered to abiotically altered glass does not show any systematic variations with age of the crust thus bioalteration lasts as long as abiotic alteration i e for as long as water is available to the hydration of the oceanic crust evidence from heat flow measurements suggests that hydrothermal circulation lasts until at least 70 ma and thus the deep biosphere is likely to expand at least into crust of this age

observations of 20 day period meridional current oscillations in the upper ocean along the pacific equator abstract prominent oscillations of the meridional current with a mean period of approximately 20 days have been observed in the upper ocean over several years from may 1979 to october 1985 using moored current measurements along the pacific equator at 95 110 124 140 w and 152 w as well as off but near the equator at 110 and 140 w the fluctuations are relatively narrowband 0 005 cpd in frequency a 95 statistically significant peak in power spectra of meridional current occurred at 110 124 and 140 w but not at 95 and 152 w where the spectral peaks were smaller the dominant wave period decreased by about 4 from 110 to 140 w maximum amplitude was measured at 124 w the amplitude above 80 m was maximum at the equator and decreased poleward from the equator at 15 m the annual averaged root mean square amplitude was about 20 5 cm s 1 and individual peak to trough values reached 150 cm s 1 the wave amplitude decreased with depth and the wave was essentially confined to the upper 80 m

the mean and the time variability of the shallow meridional overturning circulation in the tropical south pacific ocean the meridional transport in the pacific ocean subtropical cell is studied for the period from 2004 to 2011 using gridded argo temperature and salinity profiles and atmospheric reanalysis surface winds the poleward ekman and equatorward geostrophic branches of the subtropical cell exhibit an el ni no southern oscillation signature with strong meridional transport occurring during la ni and weak meridional transport during el ni no at 7 58s mean basinwide geostrophictransportabove 1000 dbar is 48 56 2 5 sv sv 10 6 m 3 s 21 of which 30 3 38 4 sv return to the subtropics in the surface ekman layer whereas 10 2 18 3 sv flow northward feeding the indonesian throughflow geostrophic transport within the subtropical cell is stronger in the ocean interiorandweakerinthewesternboundaryduringlani theinteriordominatingbasinwide transport using atmospheric reanalyses only half of the mean heat gain by the pacific north of 7 58 si s compensated by oceanicheat transport outof theregion thenationaloceanography centreat southampton air sea flux climatology is more consistent for closing the oceanic heat budget in summary the use of argo data for studying the pacific subtropical cell provides an improved estimate of basinwide mean geostrophic transport includes both interior and western boundary contributions quantifies el ni ni transport variability and illustrates how the meridional overturning cell dominates ocean heat transport at 7 58s