environmental significance of foraminiferal morphogroups in jurassic north sea deltas abstract the distribution of morphological groups of foraminifera has been analysed in toarcian and bajocian deposits of the northern north sea and the yorkshire coast the deposits are referred to prodeltaic lower delta front and interdistributary bay environments and contain mainly or entirely agglutinating assemblages of low to intermediate diversity a total of 33 agglutinating species are recognized in the studied material and these are arranged into eleven morphotypes composing seven subgroups and four morphogroups the categories are distinguished on the basis of main morphological features of the taxa combined with their life positions and micro habitats as inferred from modern analogues the prodelta deposits were formed in a normal saline and slightly stagnant depositional setting with foraminiferal faunas composed mainly of surficial and infaunal morphogroups the lower delta front and interdistributary bay sediments were deposited in shallow hyposaline waters strongly dominated by an epifaunal morphogroup with a partly phytal association a model of agglutinated morphotype distribution reveals increasing morphotype diversity and by inference ecological niche span from interdistributary bay through lower delta front to prodeltaic environments

diurnal variability in currents and temperature on the continental shelf between central and southern california 1 long time series are used to describe the diurnal variability in the meteorological and astronomical tidal forcing and the temperature and current response on the continental shelf of california between port san luis and port hueneme spectral characteristics are used to attribute the response to each of the forcing mechanisms the diurnal temperature field is decomposed into two dominant vertical modes a surface enhanced mode is coherent with the meteorological forcing suggesting that it is a direct response to local heating and wind forcing the amplitude of the second mode is maximum at middepth spectra of this mode exhibit multiple peaks at frequencies corresponding to the astronomical tidal forcing the phase difference between the middepth mode and the tidally dominated sea level is not consistent across the region we conclude that this mode is a localized baroclinic response to the astronomical tidal forcing the diurnal velocity field is dominated by a clockwise component at the surface this component is coherent across the study region and it is also coherent with the diurnal wind stress suggesting that it is a direct response to the diurnal heating and wind forcing coherence with the surface enhanced temperature mode further confirms this a weaker barotropic counterclockwise component is also present in the diurnal velocity field spectra of this component exhibit multiple peaks at periods corresponding to the astronomical tidal forcing the phase difference between this component and the surface elevation varies little between the observational sites we conclude that this velocity component represents a barotropic response to astronomical forcing that is coherent over the study area

a sequence stratigraphic model of benthic foraminiferal facies trends with triassic and jurassic examples abstract foraminiferal facies trends are outlined in a new sequence stratigraphic model embracing depositional conditions from alluvial plain to offshore shelf settings the biofacies proxies include distribution of benthic species faunal diversities and frequency of normal marine contra restricted taxa in the transgressive regressive framework biofacies trends are portrayed as assemblage expansion and reduction separated by trend changes assemblage expansion means upward increase in diversity and frequency of normal marine taxa while assemblage reduction means upward decrease of the same proxies the model is based on two modern bathymetric profiles and five mesozoic sections the latter documenting three settings in a transgressive regressive sequence 1 a deeper basinal setting with hypoxia at maximum flooding shows a trend change from assemblage expansion to reduction in the transgressive systems tract marking a shift from the restricting effect of shallow water to that of hypoxia the maximum flooding reveals a change from assemblage reduction to expansion 2 an intermediate basinal setting with normal shelf conditions at maximum flooding is typified by continuous assemblage expansion in the transgressive systems tract while the maximum flooding shows a change from expansion to reduction 3 at a basin marginal position the maximum transgression is marked by extremely low diversities and relatively homogeneous assemblages the study demonstrates that changing foraminiferal facies trends signify depositional conditions reflecting arrangement of sequence components such as flooding events systems tracts and boundaries assemblage trend changes are discrete stratigraphic horizons signalling shifts in the effect of environmental factors water depth salinity oxygenation in the sequence architecture

transtensional deformation in the central himalaya and its role in accommodating growth of the himalayan orogen 1 field mapping structural analysis and geochronologic data from northwestern nepal reveal major normal right slip motion along a previously unrecognized west northwest striking system of shear zones that we term the gurla mandhata humla fault system gmh the gmh obliquely cuts across the greater himalayan crystalline sequence and into the lesser himalayan imbricate thrust belt via two right step over structures the average slip direction on the gmh parallels the strike of the himalayan orogen motion along this fault system has resulted in an apparent left separation of the south tibet detachment main central thrust zone and lesser himalayan imbricate thrust belt along a north striking segment of the fault system we estimate a minimum of 21 km of net slip on the southern branch of the gmh by restoring the trace of the main central thrust zone parallel to the average slip direction on the fault taking into account slip estimates from the northern branch of the gmh yields a minimum net slip estimate of 24 4 to 32 4 km for the gmh the 232th 208pb ion microprobe monazite ages from leucogranite bodies indicate that motion on the gmh occurred after 15 ma its initiation immediately followed crustal thickening between the main central thrust zone and indus yalu suture zone motion on the gmh is contemporaneous with arc normal contraction in the southernmost himalayan orogen these observations can be explained by a model that involves foreland propagating structural systems facilitating arc normal contraction in the foreland and arc parallel extension in the hinterland that work together to maintain the arcuate shape of the himalayan orogen

statistical aspects of surface drifter observations of circulation in the santa barbara channel argos tracked drifters are used to study the near surface circulation in the santa barbara channel the mean consists of a cyclonic cell in the western santa barbara channel with weaker flow in the eastern channel drifter mean velocities agree well with record means from near surface current meters at the eastern entrance to the channel drifter velocities are biased toward outflow eastward velocity conditions drifter variability at synoptic and seasonal scales shows a tendency for upwelling and eastward flow in spring a strong cyclonic circulation in summer poleward relaxation in fall and weak variable circulation in winter drifter estimates of eddy stress divergence indicate advective terms play a secondary role in the mean surface momentum balance lagrangian time and space scales are about 1 day and under 10 km respectively the mismatch between lagrangian and eulerian timescales indicates advective terms are important to the fluctuating circulation

basin formation in the high himalaya by arc parallel extension and tectonic damming zhada basin southwestern tibet 1 the late miocene pleistocene zhada basin in southwestern tibet provides a record of subsidence and basin formation within an active collisional thrust belt the 800 m thick basin fill is undeformed and was deposited along an angular unconformity on top of tethyan strata that were previously shortened in the himalayan fold thrust belt modal sandstone petrographic data conglomerate clast count data and detrital zircon u pb age spectra indicate a transition from detritus dominated by a distal northern source to a local southern source this transition was accompanied by a change in paleocurrent directions from uniformly northwestward to basin centric at the same time the depositional environment in the zhada basin changed from a large braided river to a closed basin lake sedimentation in the zhada basin was synchronous with displacement on the qusum and gurla mandhata detachment faults which root beneath the basin and exhume midcrustal rocks along the northwestern and southeastern flanks of the basin respectively these observations indicate that accommodation for zhada basin fill was produced by a combination of tectonic subsidence and damming as midcrustal rocks were evacuated from beneath the zhada basin in response to arc parallel slip on crustal scale detachment faults

circulation in the point conception santa barbara channel region during spring and early summer 1983 fifteen current moorings were deployed around the periphery of santa barbara channel and over the continental shelf to the west off point conception data from these moorings have been used to describe the regional circulation and to address problems of wind forcing and the spatial coherency scales for current fluctuations the mean circulation in santa barbara channel was dominated by a westward jet which occupied the northwestern portion of the channel current and temperature fluctuations were generally well correlated among all locations around the channel and time lags suggested cyclonic propagation of events around the channel the time fluctuations were dominated by a relatively few low frequency events it was impossible to determine exactly either the driving mechanisms for these events or their relationships to regional flow the flow regime was considerably different off point conception than in the channel locally wind driven upwelling was observed in both the mean and fluctuating flows and the time scales of current variability i e spectral shapes mimicked those of the local winds a dramatic change in the regime off point conception occurred in late may before the transition currents and sea levels had been well correlated in time with both local and remote winds after late may the relation to fluctuating winds was less clear and the alongshore structure of sea level variability had changed radically

wind induced currents and bottom trapped waves in the santa barbara channel the santa barbara channel sbc is a coastal basin about 100 km long bounded by the southern california mainland on the north and by a chain of islands on the south the sbc is at most 50 km wide and just over 600 m deep the nature of current and wind variance peaks in the 2 4 day and 4 6 day bands in the channel are analyzed from january to july 1984 for both bands the dominant empirical mode of the currents is highly coherent with the dominant empirical mode of the winds over this region surface intensification of currents is revealed by measurements made between 25 and 300 m in contrast the deeper currents are characterized by bottom trapping evidence for baroclinic bottom trapped topographic rossby waves is found on the northern shelf at the western mouth of the channel in both frequency bands at 30 m the distribution of phases shows currents at the center of the western mouth leading the southern interisland passes by about 0 3 day and the eastern mouth by about 0 6 day in both bands co and quadrature vectors of currents and winds describe this wind current system in detail it is speculated from spatial and temporal eigenfunctions of currents and winds and from available satellite images that the dominant current mode described above is a channelwide response to upwelling north of point conception northwestward of the sbc the upwelling related currents cause a net inflow of mass into the western end of the channel which is compensated by an outflow passing through both the interisland passes and through the eastern mouth of the channel as a result of the narrowness and shallowness of the passes and of the shallowness of the southern shelf in general high flow speeds are attained there that the authors speculate seem to force deep high frequency motions both at the center of the sbc and at the northern half of its western mouth

a curious relationship between the winds and currents at the western entrance of the santa barbara channel 1 relationships between the surface winds and acoustic doppler current profiler adcp currents at 20 levels 25 to 329 m at the western entrance of the santa barbara channel sbc at national data buoy center ndbc buoy 46054 are evaluated for the 1 year period from 1 june 1996 through 31 may 1997 using a relatively new technique for correlating vectors gaps in the data were filled and the resulting time series examined to insure that the statistical properties of the edited data had not been significantly altered vertical current profiles averaged over the year indicate that the mean signal although well defined is smaller than the variability about the mean vertical profiles of current speed and direction suggest the possibility of at least a two layer system of circulation in the sbc with flow between 25 and 180 m being to the ssw and flow from 260 to 329 m being to the ene in agreement with previous results because of the existing dynamical balances the currents are oriented approximately sw ne and the direction of the vertical current shear i e the thermal wind is essentially constant with depth thus warmer waters lie to the north and west and colder waters essentially south of the buoy are consistent with observed cyclonic circulation at the western entrance of the channel vector correlations over the entire year indicate that the winds and currents are poorly correlated consistent with previous results however correlations between the winds and currents below180 m increase noticeably with increasing depth a result which was not anticipated the surface winds and near surface currents in the sbc have repeatedly shown a seasonal connection between january and april and often into may our results show the same pattern and further quantify the strength of this relationship contrary to previous results however we find a relationship between the winds and currents during this period that extends well below the near surface region down to at least 300 m vector correlations between the currents per se at different levels show quite different patterns over time suggesting the influence of independent in water sources of variability finally lagged vector correlations were calculated at four depths 21 41 121 and 313 m for two 3 month periods the first from october through december 1996 a period when a strong connection between the winds and currents was not expected and the second during the spring february through april 1997 when it was expected for the first case correlations increased after the first inertial period at 25 m and 41 m at 313 m an immediate response i e maximum response at zero lag was observed with maximum correlations decaying rapidly over the first inertial period during the spring an immediate response at all four depths similar to the response observed at 313 m during the first period was observed these results imply the importance of the inertial period as a relevant time scale satellite imagery reveals a major frontal zone often located in the vicinity of the buoy vertical sections of temperature and velocity along the axis of the sbc from the princeton ocean model suggest that upwelled waters flowing into the channel from the nw are subducted below the warmer waters that flow through the channel from the east at a location probably not far from the surface front seen from space these model results are consistent with the argument that the higher correlations below 180 m together with a rapid response to wind forcing occur because the deeper waters in the sbc have had recent contact with surface winds prior to their entry into the sbc i e good short term memory lower correlations at intermediate depths 25 180 m for waters flowing to the west may occur because they do not have direct contact with the surface wind due to the presence of a shallow 25 m surface layer and that their motion is partially guided by the channel itself and driven by advective forces outside the sbc

isotopic characteristics of the gurla mandhata metamorphic core complex implications for the architecture of the himalayan orogen isotopic data from the gurla mandhata metamorphic core complex provide insight on the character of rocks exposed within it and permit possible correlations of these rocks to those exposed in the himalayan thrust belt whole rock sr and nd isotopic analyses show that rock units in the metamorphic core have isotopic signatures that correlate to those of greater and lesser himalayan rocks exposed in the foreland these data are the first to document lesser himalayan rocks north of the higher himalayan physiographic zone when combined with previously published structural reconstructions of the himalayan orogen these data reveal a crustal architecture that requires significant uplift of lesser himalayan rocks in the hinterland with respect to their position in the foreland a greater amount of underthrusting of the lesser himalayan rocks and more shortening in the hinterland within the tethyan himalaya physiographic zone than currently estimated

seismotectonics of the nepal himalaya from a local seismic network the national seismological network of nepal consists of 17 short period seismic stations operated since 1994 it provides an exceptional view of the microseismic activity over nearly one third of the himalayan arc including the only segment between longitudes 78 e and 85 e that has not produced any m 8 earthquakes over the last century it shows a belt of seismicity that follows approximately the front of the higher himalaya with most of the seismic moment being released at depths between 10 and 20 km this belt of seismicity is interpreted to reflect interseismic stress accumulation in the upper crust associated with creep in the lower crust beneath the higher himalaya the seismic activity is more intense around 82 e in far western nepal and around 87 e in eastern nepal western nepal between 82 5 and 85 e is characterized by a particularly low level of seismic activity we propose that these lateral variations are related to segmentation of the main himalayan thrust fault the major junctions between the different segments would thus lie at about 87 e and 82 e with possibly an intermediate one at about 85 e these junctions seem to coincide with some of the active normal faults in southern tibet lateral variation of seismic activity is also found to correlate with lateral variations of geological structures suggesting that segmentation is a long lived feature we infer four 250 400 km long segments that could produce earthquakes comparable to the m 8 4 bihar nepal earthquake that struck eastern nepal in 1934 assuming the model of the characteristic earthquake the recurrence interval between two such earthquakes on a given segment is between 130 and 260 years

environmental significance of foraminiferal assemblages dominated by small sized ammodiscus and trochammina in triassic and jurassic delta influenced deposits abstract the sediment packages analyzed for benthic foraminifera consist of mudstones with interbedded sandstones deposited in shallow delta influenced shelf to deltaic environments the sections are located in spitsbergen the barents sea northern north sea and yorkshire and range in age from late triassic to middle jurassic salient features of the foraminiferal successions are 1 the assemblages consist entirely or dominantly of agglutinated taxa 2 the faunal diversities are extremely low 3 the dominant genera are ammodiscus and trochammina 4 the species are generally of small size compared to usual dimensions within the genera the features listed above suggest that the assemblages were adapted to restricted conditions clearly divergent from those of a normal marine shelf where the main limiting factors were low salinity and reduced amount of dissolved oxygen in unstable storm influenced environments evidence for environmental conditions is obtained from modern analogues although the large evolutionary changes in foraminifera during post jurassic time make it difficult to find such analogues additional information is derived from functional morphology sedimentary features and paleogeography the analyzed sediment packages show close faunal similarities suggesting opening of a marine pathway which connected the paleo arctic ocean with the western european shelf seas in early jurassic a depositional biofacies model of the small sized ammodiscus trochammina assemblages envisages a delta influenced shelf environment where high freshwater influx would have created a density stratified water column with a tendency to develop hypoxic conditions in its deeper parts the depth interval between fair weather and storm wave base the offshore transition zone is indicated as the habitat of the small sized ammodiscus trochammina assemblages in this zone benthic biota would have been stressed by intermittent periods with moderate hypoxia combined with lowered salinity and storm impacts

calcareous phytoplankton response to the half century of interannual climatic variability in santa barbara basin california 1 a high resolution study of calcareous phytoplankton in a box core from the santa barbara basin sbb reveals floral assemblage fluctuations which can be related to climatic and paleoceanographic changes during the last half century 1940 1996 in particular gephyrocapsa oceanica production increased during el nino periods in response to high temperatures silica depletion and increased iron availability conversely helicosphaera carteri flux increases in conjunction with lower surface temperatures associated with la nina episodes increasing abundances of florisphaera profunda and umbilicosphaera sibogae after 1970 reflect a warming trend and increased stratification within the basin associated with the warm phase of the pacific decadal oscillation pdo conversely increased abundances of coccolithus pelagicus and calcidiscus leptoporus before 1970 mark the cold phase of pdo these coccolithophore production rate data are consistent with instrumental records of surface and thermocline temperatures monitored since 1950 this is the first study to document the response of calcareous phytoplankton to surface water warming occurring in sbb since 1970

late miocene topographic inversion in southwest tibet based on integrated paleoelevation reconstructions and structural history article investigations of the deformation history of the himalayan orogen support interpretations of rapid and striking changes in the landscape of the tibetan himalaya and high himalaya we examine this issue by integrating oxygen isotope based paleoelevation reconstructions of the zada basin in southwestern tibet with information on the structural evolution of the high and tibetan himalaya between 79 e and 84 30 e 18 opsw values were calculated from 18 occ values from pristine fluvial miocene gastropod shells analyses comparing the most negative 18 osw and reconstructed 18 opsw values to 18 osw versus elevation relationships based on both thermodynamic models and an empirical data set suggest a decrease in the mean watershed elevation of 1 to 1 5 km since the late miocene geologic mapping and structural data from crustal scale fault systems in the zada region and regions to its east indicate a phase of arc normal shortening and vertical thickening since the middle miocene followed by ongoing arc parallel extension and vertical thinning these results suggest that regions in this part of the orogen transitioned from undergoing arc normal shortening to arc parallel extension in the late miocene and that arc parallel extensional structures root deeply within the himalayan thrust wedge when combined with data on the distribution age and provenance of sedimentary basins our geologic mapping structural data and paleoelevation results suggest that this transition from shortening to extension was accompanied by a topographic inversion from mountains to basins in b4 m y these observations can be explained by a foreland propagating fault system that accommodates outward radial expansion of the himalayan orogen

marine shelf to paralic biofacies of upper triassic to lower jurassic deposits in spitsbergen abstract the upper triassic to lower jurassic kapp toscana group of spitsbergen consists of mudstones sandstones and shales deposited in offshore marine to paralic conditions in an extensive shelf embayment the study focuses on microfossil based biofacies features mainly foraminifera but also palynomorphs combined with sedimentary and selected geochemical data in relation to transgressive regressive developments the analysed material includes field logs and sediment samples originating from the juvdalskampen section central spitsbergen the benthic foraminiferal succession reveals three principal associations 1 assemblages of mixed agglutinated and calcareous components typified by medium to high diversities indicating offshore shelf conditions 2 assemblages consisting dominantly or entirely of agglutinated forms with low diversity attributed to hyposaline conditions 3 highly impoverished agglutinated assemblages or barren samples suggesting extremely brackish to freshwater environments the marine influence is highest in the lower and upper parts and lowest in the middle part of the kapp toscana group as indicated both by foraminiferal and palynomorph proxies the potential of the boron concentration as a salinity indicator is demonstrated by its co variance with biofacies features the boron content increases with increasing salinity the kapp toscana group consists of two depositional sequences the storfjorden sequence carnian to early norian starts with a transgressive systems tract formed in offshore shelf conditions with normal marine salinity and terminates at the maximum flooding event which is succeeded by a highstand systems tract deposited in paralic hyposaline to freshwater prodelta to delta plain environments the overlying wilhelmoya sequence middle norian to bajocian is punctuated by several hiatuses and was deposited in hyposaline waters on a sediment starved prodelta shelf platform

changing depositional environments reflected by foraminifera in a transgressive regressive sequence of the lower cretaceous on spitsbergen abstract the boreal valanginian to barremian foraminiferal succession of the rurikfjellet formation in central spitsbergen is applied to stratigraphic zonation analyses of depositional conditions and developing a sequence stratigraphic model the study is based on the janusfjellet section where the formation is 204 m thick and represents a depth range from upper bathyal to prodelta top it contains a continuous benthic foraminiferal succession permitting distinction of five assemblage zones the assemblages are almost entirely agglutinated and reflect calcium carbonate depletion which appears as an overall feature of mesozoic boreal seas superimposed on other but more local restricting factors such as salinity and food supply close taxonomic similarities within the boreal realm are revealed by comparison of the janusfjellet foraminiferal faunas to those of other pan arctic sites the lower half of the janusfjellet section contains a significant faunal component comparable to modern bathyal faunas and late cretaceous to paleogene flysch type assemblages indicating upper bathyal to offshore shelf depths in the upper half of the section increased diversities are created by enhanced food supply in middle shelf setting this is succeeded by increasing deltaic impact leading to hyposaline environments reflected by low species diversities changing foraminiferal biofacies trends through the janusfjellet section are portrayed in the framework of the third order transgressive regressive wimanfjellet sequence its transgressive systems tract was deposited mainly at upper bathyal depths with maximum flooding surface in the lower valanginian part of the rurikfjellet formation the regressive systems tract reveals an upward shoaling succession from upper bathyal conditions through marine shelf to hyposaline prodelta setting

main features of foraminiferal distribution reflecting estuarine hydrography in oslo fjord abstract foraminiferal assemblages have been analysed in sediment surface samples located along three profiles covering the depth interval 1 120 m in breidangen a wide basin forming the middle portion of oslo fjord the study concentrates on the distribution of major faunal features including suborders and diversities number of species shannon wiener index equitability in addition species distribution is recorded and q mode factor analysis has distinguished six assemblages measurements of hydrographical properties temperature salinity dissolved oxygen reveal the estuarine stratification of the water column which is reflected also by the faunal parameters on the basis of these features the following subdivision is proposed with increasing depth 1 seasonal layer dominated by calcareous species in the upper and agglutinated species in the lower part with low to intermediate diversities 2 transitional layer characterized by a maximum in diversity and a reduction in the agglutinated component 3 stable deeper water showing high diversity and a further decrease in the agglutinated component the generally higher frequency of calcareous foraminifera below the seasonal water layer on the eastern side of breidangen compared to the western side is mainly attributed to the influence of inflowing skagerrak water additionally it may be a result of increased supply of organic matter to the western side increasing the oxygen demand in this area

near bed solibores over the continental slope in the faeroe shetland channel abstract on two occasions within a 12 day measurement period in the faeroe shetland channel strongly nonlinear wave trains were observed at the sea bed propagating up the continental slope in water depths 450 m the events were separated by a period of 4 days and whilst resembling in appearance a density current running up a slope are termed solibores displaying the properties of both turbulent internal bores and nonlinear internal solitary waves isw each solibore displays a steep leading edge followed by a train of nonlinear waves with amplitudes of o 10 m and periods of 5 20 min wave induced particle velocities are consistent with isw whilst a zone of strong horizontal convergence at the leading edge of the solibores causes the formation of a rotor with flow in the opposite sense to a forward overturning surface wave in both cases upward vertical velocities 10 cm s 1 are immediately followed by a return downward flow of equal magnitude a ctd and microstructure transect conducted during the passage of the first solibore illustrates its behaviour as an up slope intrusion of cold dense water with concurrent rates of turbulent dissipation e of o 10 7 w kg 1 and resulting in short term maximum vertical diffusivities kz of o 10 1 m2 s 1 in the long term however kz 140 days which again indicate intermittency in periods of enhanced sediment flux the solibores are consistent with the results of numerical and laboratory experiments on hydraulic jumps resulting from shoaling isw the influence of the slope is proposed to be the reason for their slightly different forms and effects on sediment transport thus the first solibore propagating directly up the slope is proposed to result from an overturning hydraulic jump caused by kinematic instabilities and which subsequently forms a horizontal density intrusion the second solibore represents a dispersive wave train due its oblique direction of propagation which reduces the effective bottom slope allowing dispersion to balance nonlinear effects and prohibiting overturning

living hydromagnesite stromatolites from turkey abstract salda golu lake in southern turkey is a highly alkaline ph 9 freshwater lake in which composite stromatolites several metres high are formed by microbially induced precipitation of hydromagnesite the magnesium and carbonate in the lake waters were dissolved during passage through ultramafic rocks precipitation is brought about by the flora of diatoms and cyanobacteria forming the surface of the stromatolites but does not occur in direct contact with cells stromatolites have previously been reported from environments ranging from fully marine through brackish water to a variety of freshwater lacustrine and fluvial situations the principal importance of these structures lies in their novel mineralogy hydromagnesite mg4 oh 2 co3 3 3h2o is commonly regarded as a low temperature hydrothermal mineral

wind stress curl forcing of the coastal ocean near point conception california near point conception california the atmospheric flow separates from the coast and a large wind stress curl results direct spatial wind field observations from 20 aircraft overflights in the spring of 1983 suggest that ekman pumping of on average 4 m day21 contributes to the local dynamics during strong and persistent upwelling events the curl driven ekman pumping reaches up to 20 m day21 a single complex empirical orthogonal function explains more than 72 of the spatial and temporal wind stress variance it reveals large wind stress curl at the center of the western santa barbara channel entrance this dominant mode correlates strongly r 2 5 0 79 with the wind stress observed at a moored buoy the location of largest ekman pumping in the ocean indicated by this mode coincides with the location of a laterally sheared cyclonic flow cold upwelled waters enter the santa barbara channel along its southern perimeter while warm and thus buoyant waters from the southern california bight exit the channel along its northern perimeter buoy wind stress and lateral current shear at 30 m depth correlate significantly at periods of about 3 5 and 6 days with phase lags of about 0 5 and 2 days respectively hydrographic observations from 1983 do not however indicate effects of ekman pumping on the internal mass field as winds vary in speed and direction at daily timescales this contrasts with 1984 observations that do indicate strong doming of isopycnals over the center of the channel at its western entrance winds prior to and during hydrographic observations in the spring of 1984 were both stronger and more steady than they were in 1983 cyclonic shears reach 0 4 f at the entrance of the santa barbara channel near point conception here f is the planetary vorticity the thermal wind balance explains the lateral shear of the alongchannel surface flow rather well

mass and heat balances in the santa barbara channel estimation description and forcing abstract current meter temperature and wind observations from the 1984 mms experiment are used to estimate the mass and heat budgets in the santa barbara channel the mass transports estimated at the western eastern and southern boundaries of the channel are characterized by fluctuations whose energy is concentrated around three different periods 5 14 and 2 8 days respectively these three transports fluctuate along with the dominant eof modes obtained at those 3 entrances respectively the mean transport passing through the channel from east to west is about 0 28 sv there are two frequency bands where winds and mass transports are coherent 2 5 3 0 and 4 7 5 2 day bands winds on the northern shelf lead the transports in both bands by about 1 0 day at the western half of the channel there is a recirculating counterclockwise mean transport of about 0 30 sv the time dependent part of the recirculating transport is coherent with the wind in the 4 7 5 2 day band where it also shows an absolute maximum of variance the recirculating transport lags the local downwelling favorable winds by about 1 5 day and seems to be the channel response to wind relaxations with respect to its most persistent upwelling favorable state the main mean balance in the channel integrated heat equation is between the heat transport passing through the western mouth which cools off the channel and the heat transport caused by the mass transport the transport heat flux which warms up the channel this latter transport results from the advection of the temperature difference between the channel boundaries mainly east and west by the mass transport there are no two terms that dominate the heat equation for the time dependent heat transports but it can be simplified by balancing the along channel heat divergence heat transport passing through the mouth plus transport heat flux the vertical heat flux and the local change of heat a clear thermal wind balance at the eastern and western ends of the channel is found in agreement with the work of brink and muench 1986 journal of geophysical research 91 877 895 and with the recent adcp ctd comparisons done by richards personal communication all the terms in the heat equation show a variance peak in the 2 4 day band it is found that when upwelling favorable winds blow on the northern shelf of the channel there is first a decrease or even a reversal with respect to its mean in the amplitude of the transport heat flux next a cooling of the santa barbara channel is observed followed by a loss of heat through the western mouth first and through the eastern mouth later this whole process takes about 24 h to complete