the evolution of oceanic and atmospheric anomalies in the northeast pacific during the el nino and la nina events of 1995 2001 abstract from late 1995 through early 2001 three major interannual climate events occurred in the tropical pacific the 1995 97 la nina ln 1997 98 el nino en and 1998 2001 ln we analyze atmospheric and upper oceanic anomalies in the northeast pacific nep during these events and compare them to anomalies both elsewhere in the north and tropical pacific and to typical en and ln anomaly patterns the atmospheric and oceanic anomalies varied strongly on intraseasonal and interannual scales during the 1995 97 ln and 1997 98 en the northeast pacific was dominated by negative slp and cyclonic wind anomalies and by upper ocean temperature and sea surface height ssh anomalies the latter were positive along the north american west coast and in the nep thermal anomaly pool between hawaii vancouver island and baja california and negative in the central north pacific this atmospheric oceanic anomaly pattern is typical of en an eastward shift in the atmospheric teleconnection from east asia created en like anomalies in the nep during the 1995 97 ln well before the 1997 98 en had begun the persistence of negative sea level pressure slp and cyclonic wind anomalies in the nep during the 1997 98 en intensified pre existing upper oceanic anomalies atmospheric anomalies were shifted eastward during late 1996 early 1998 leading to a similar onshore shift of oceanic anomalies this produced exceptionally strong positive upper ocean temperature and ssh anomalies along the west coast during the 1997 98 en and explains the unusual coastal occurrences of several species of large pelagic warm water fishes the growth and eastward shift of these pre existing anomalies does not appear to have been linked to tropical pacific en anomalies until late 1997 when a clear atmospheric teleconnection between the two regions developed prior to this remote atmospheric impacts on the nep were primarily from east asia as the 1998 2001 ln developed nep anomalies began reversing toward the typical ln pattern this led to predominantly negative slp and cyclonic wind anomalies in the nep and upper ocean temperature and ssh anomalies that were mainly negative along the west coast and positive in the central north pacific the persistence of these anomalies into mid 2001 and a number of concurrent biological changes in the nep suggest that a decadal climate shift may have occurred in late 1998 during 1995 2001 nep oceanic anomalies tracked the overlying atmospheric anomalies as indicated by the maintenance of a characteristic spatial relationship between these anomalies in particular wind stress curl and ssh anomalies in the nep maintained an inverse relationship that strengthened and shifted eastward toward the west coast during late 1996 early 1998 this consistent relationship indicates that anomalous ekman transport driven by regional atmospheric forcing was an important contributor to temperature and ssh anomalies in the nep and ccs during the 1997 98 en other studies have shown that coastal propagations originating from the tropical pacific also may have contributed to coastal nep anomalies during this en our results indicate that at least some of this coastal anomaly signal may have been generated by regional atmospheric forcing within the nep

millennial scale changes in sea surface temperature and ocean circulation in the northeast pacific 10 60 kyr bp 1 a new centennial scale mg ca temperature record from the california margin odp site 1017e reveals large millennial scale oscillations between 10 to 60 kyr this record indicates that sea surface temperature on the california margin warmed rapidly on the deglacial by 7 4 0 8 c and was preceded by a pre bolling temperature oscillation of 2 6 1 2 c millennial scale events of the last glacial episode were marked by sea surface temperature oscillations of between 3 and 7 c on the california margin and interstadials were associated with an increase in surface water salinity the data are consistent with evidence for a glacial southward shift in the polar jet stream and concomitant strengthening of the relatively cold fresh california current during stadial events the data also support previous hypotheses suggesting a tight coupling between the north atlantic and northeast pacific response to climate instability of the last glacial episode

coupling the wrf model with a temperature index model based on remote sensing for snowmelt simulations in a river basin in the altay mountains north west china

assimilation of moored velocity data in a model of coastal wind driven circulation off oregon multivariate capabilities 1 horizontal current measurements from an array of moored acoustic doppler profilers are assimilated sequentially into a model of coastal wind driven circulation off oregon during the upwelling season of may august 2001 model results are compared against independent moored and ship survey data to document a positive effect of velocity data assimilation da on other oceanic variables of interest such as the sea surface height ssh temperature potential density surface salinity and near bottom turbulence parameters significant improvement is achieved for the nearshore ssh even when data are assimilated from only two moorings at an alongshore distance of 50 km from the ssh verification site at 45 n in an area of simple shelf bathymetry with relatively small alongshore variations the model even without da provides a good description of the isopycnal structure on a cross shore section at 44 2 n over complicated bathymetry velocity da may improve the slope of isopycnals but at the same time not necessarily the density values themselves data assimilation based on a time invariant representation of the forecast error covariance may inhibit spatial variability on horizontal scales smaller than the assumed forecast error decorrelation scale an experiment involving assimilation of both velocity and moored salinity measurements demonstrates that moored velocity da improves transport of buoyant surface water the level of improvement in the near bottom turbulent dissipation and bottom stress found with the da model indicates that it is suitable for future studies of spatial and temporal variability in the bottom boundary layer off oregon

moored wind temperature and current observations made during coastal ocean dynamics experiments 1 and 2 over the northern california continental shelf and upper slope moored observations of winds currents and temperature made over the northern california shelf and upper slope during the 1981 and 1982 upwelling seasons as part of the coastal ocean dynamics experiment code are described in both field experiments code 1 and code 2 the onset of the upwelling season is triggered by the strengthening of the north pacific high off northern california and signalled by the presence of water colder than 9 c near the bottom over the shelf vertical temperature stratification over the shelf is reduced during active upwelling local winds and subtidal currents over the shelf are strongly polarized in the alongshelf direction and the mean wind stress is directed equatorward response of alongshelf currents to wind forcing is similar at all depths over the shelf the response of the cross shelf current is more complex in the surface layer offshelf flow is significantly and positively correlated with the upwelling favorable alongshelf wind stress beneath this layer a weak return flow exists the thickness of the upper mixed layer varies greatly reaching 60 m during upwelling events thus direct wind forcing affects a substantial fraction of the water over the shelf low frequency wind stress current and temperature fields are adequately described by a few energetic empirical orthogonal functions with simple spatial structure the most energetic mode typically accounts for 75 or more of the variance of wind stress and temperature over the middle and inner shelf the most energetic current mode accounts for 90 or more of the variance is dominated by he alongshelf component and veers to the left with depth the low frequency alongshelf flow fluctuations are quasi barotropic with some vertical shear but no reversal with depth vertical shear in alongshelf current and the cross shelf density gradient obey the thermal wind relation the simple structure of the subdiurnal currents allow estimation of the alongshelf volume transport between the 60 and 130 m isobaths through three cross shelf transects in code 2 volume transport over the shelf is often nearly two dimensional but occasional large differences indicate significant mass exchange between the shelf and the adjacent upper slope correlation of low frequency currents and alongshelf wind stress shows the response of alongshelf current to be maximum near the surface and near midshelf where a 15 cm 1 alongshelf flow lags a 1 dyn cm 2 alongshelf wind stress by the order of 10 hours currents over the upper slope are not significantly correlated with local wind alongshelf transport over the shelf is highly correlated with local wind stress explaining 80 of the variance in the low frequency transport during code 2 volume transport is best correlated with wind stress approximately 30 km to the south winds in the code area during spring and summer are characterized by strong and persistent upwelling favorable winds interrupted by shorter periods of weak winds regression analysis indicates that in the absence of wind a poleward barotropic current jet exists over the shelf with a maximum amplitude over the inner shelf in the code area an upwelling favorable wind counters this jet over the shelf so that the alongshore flow is everywhere equator ward during strong wind events since the maximum response to wind forcing is found at midshelf and near surface the mean current over the upwelling season is strongly sheared in both the vertical and cross shelf directions mean flow over the outer shelf is surface intensified and is directed offshelf and equatorward while the deeper flow at midshelf and through most of the water column over the inner shelf is directed poleward

shelf response to intense offshore wind this is the accepted version of the following article grifoll m aretxabaleta a espino m shelf response to intense offshore wind journal of geophysical research setembre 2015 vol 120 num 9 p 6564 6580 which has been published in final form at http onlinelibrary wiley com doi 10 1002 2015jc010850 full

upwelling and cyclonic regimes of the near surface circulation in the santa barbara channel the observed near surface circulation in the santa barbara channel indicates in particular two patterns a dominant cyclonic circulation mode and a less frequent upwelling flow mode to explain the dynamics that may govern these two flow regimes momentum balance from a hindcast model of currents in the channel forced by observed hourly winds and hydrographic data was calculated the along channel balance was found to be between wind which was eastward i e equatorward sea level tilt which was westward i e poleward and coriolis which was westward if the wind was 1 intense west and east of the channel and was eastward if the wind was 2 weaker in the east wind condition 1 produced southward cross channel flow in the midchannel connected by eastward currents upstream downstream along the northern southern coast of the channel while wind condition 2 produced northward cross channel flow connected by cyclonic recirculation in the west and westward inflow in the east it is suggested that the former corresponds to the dynamical balance that may occur in the upwelling flow mode while the latter corresponds to the cyclonic circulation mode

interannual westward propagating baroclinic long wave activity on line p in the eastern midlatitude north pacific abstract for the period 1959 81 quasi zonal hydrographic sections have been made between the southern coast of vancouver island 49 n 126 w and ocean station p 50 n 145 w approximately every two months along this section called line p hydrographic std stations were repeated at nearly the same locations approximately 2 of longitude apart and at closer intervals near the coast as such 13 stations in all were made nearly every two months over the 23 year period thus the line p dataset has particular value in verifying the existence of interannual baroclinic long waves near 50 n in previous studies white kang and magaard and white and saur had found evidence of annual and interannual baroclinic long wave activity in the eastern midlatitude north pacific over the range 20 40 n but earlier attempts could not discover these westward traveling waves along line p in this study both spectral analysis and complex empirical orthogonal function analysis are used to do just that concentrating u

impact of open ocean influence on a coastal model the 1997 1998 el nino off central california 1 extensive moored current meters atmospheric observations and hydrographic surveys were obtained off central california during the 1997 1998 el nino in this study the temperature observations from current meter moorings and hydrographic surveys are assimilated into a coastal ocean model to study the seasonal circulation in the santa barbara channel santa maria basin sbc smb mean coastal circulation was dominated by a poleward jet in fall 1997 at the peak of the el nino but returned to the normal surface convergent pattern in fall 1998 the data assimilated model reproduces well the observed flow patterns in both years the interannual flow variability is examined through sensitivity analysis of the effects of local forcing and open ocean influence it is shown that the poleward jet is associated with enhanced california countercurrent during el nino while the surface convergence is driven by local wind stress curl taking advantage of the extensive data set the climatology is compared with the synoptic states it is found that the climatology could cause significant negative impact

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

lagrangian assessment of simulated surface current dispersion in the coastal ocean 1 a purely lagrangian assessment of dispersion from modeled surface current trajectories in the coastal ocean is presented modeled trajectories come from roms simulations for the southern california bight during the 1996 through 1999 period data are from surface current trajectories collected primarily in the santa barbara channel with code style drifters distributions of particle positions from trajectories emanating from launch locations within 10 kilometers of the coast throughout the santa barbara channel that advect for one through four days lagrangian pdfs are evaluated descriptively and quantitatively the two dimensional kolmogorov smirnov k s statistical test for comparing discrete sampled data with a known probability distribution is the quantitative basis in general dispersion distributions from observations are similar to lagrangian pdfs computed from modeled trajectories and the k s statistic quantifies this accordingly a few specific regions of poor model data agreement are indicated and discussed the purely lagrangian assessment elucidates an improved understanding of model performance and ocean circulation beyond that offered in a eulerian sense and is necessary when modeled trajectories are utilized for applied oceanographic and marine ecology problems

circulation in the santa maria basin california during 1998 1 moored observations and numerical model results are used to describe the circulation during 1998 in santa maria basin smb and santa barbara channel sbc located to the northwest and southeast respectively of a bend in the southern california coastline singular value decomposition svd analysis of observed wind stress and currents yields a first mode that represents large scale alongshore flow variability that appears to be wind driven and a second mode which mostly represents flow variability in sbc and appears coherent with wind stress shear there a three dimensional numerical ocean circulation model is used to simulate the flow the model derived surface heat flux is most similar to observation derived values in summer and least similar in winter and more similar in smb than in sbc empirical orthogonal function eof analysis of the coriolis and pressure gradient terms for modeled near surface currents supports the hypothesis that the large scale flow variability of the first mode is wind driven it further suggests that an alongshore pressure gradient drives the poleward flow along sbc s northern shelf wind stress curl of which the shear along sbc is a part or its gradient may govern such a pressure gradient although this could not be ascertained modeled and observed currents are similar in their directions but both the annual mean and variance tend to be smaller for modeled flow svd analysis shows that modeled and observed flows have similar modes of variability remotely driven flow may play a role in smb especially in summer

characteristic patterns of the circulation in the santa barbara channel the subtidal near surface circulation in the santa barbara channel sbc and on the shelf north of point conception is described based on observations obtained during the 3 year period from 1993 to 1995 near surface currents in the channel are a superposition of a larger than sbc scale flow and a cyclonic circulation of variable intensity located inside the channel on seasonal timescales the larger than sbc scale flow near the surface is equatorward in spring and poleward from summer through winter the increase in equatorward flow in spring occurs concurrently with the increase in equatorward wind stress and the decrease in near surface temperatures and synthetic subsurface pressures ssps the flow reverses in late spring simultaneously with the increase in the along channel ssp difference and months before wind stress has reached its peak the period during which the cyclonic circulation within the sbc is strongest coincides with the period of strongest poleward flow through the eastern entrance a synoptic description of the circulation in the sbc is presented in terms of six characteristic patterns labeled upwelling relaxation cyclonic propagating cyclones flood east and flood west an analysis of the 5 and 45 m currents into empirical orthogonal functions eofs isolates 50 53 of the 5 m 45 m low frequency current variance into three two modes combining these modes with the mean current fields the modes have spatial patterns that correspond to the characteristic flow patterns subjectively deduced from inspection of daily averages of the near surface currents from late spring through fall the two largest 5 m current modes produce a repeating pattern of circulation in which the sequence of four states namely upwelling cyclonic relaxation and quiescent is traversed roughly every 16 days in addition to the large scale cyclonicity in the central sbc smaller cyclonic eddies form frequently in the eastern channel and travel toward the west with an average speed of 0 06 m s 1 the patterns described here develop in response to the wind stress and the along channel ssp gradient

objective maps of near surface flow states near point conception california abstract objective streamfunction and velocity potential maps of three commonly observed flow states near point conception california are derived from moored current meter and drifter observations the states are defined using current meter data drifter data are sorted by flow state and averaged within spatial bins to resolve their spatial structures spatial correlations of drifter data show the along shelf and cross shelf decorrelation distances are approximately 45 and 25 km respectively this information is used to make the objective streamfunction and velocity potential maps the total velocity is represented as the sum of the rotational nondivergent streamfunction component and the irrotational divergent velocity potential component the velocity derived from the streamfunction is much stronger than that derived from the velocity potential the streamfunction is sufficiently well resolved to make meaningful vorticity maps the velocity potential indicates a source term in the western santa bar

characterizing long island sound outflows from hf radar using self organizing maps abstract the surface outflows from the long island sound are examined from one year records of hf radar codar observations synoptic flow patterns are identified using manual classification empirical orthogonal function eof decomposition and self organizing maps som four characteristic flow patterns for the spring summer and fall winter seasons each are obtained through a 2 2 som array the som is confirmed by comparison with manual classification and is shown to be a significant improvement over eof classification it is suggested that the degrees of freedom of the leading eof modes can be used as a constraint on the otherwise arbitrary som dimension the relationship between the flow patterns and the winds also can be conveniently examined in som the outflows are shown to interact strongly with the ambient coastal currents both of which are under the influence of the winds this result challenges the conventional wisdom which often treats the outflows independent of the ambient currents the advantage of using som in synthesizing and interpreting synoptic hf radar observations is clearly demonstrated

a distributed temperature index ice and snowmelt model including potential direct solar radiation hourly melt and discharge of storglaciaren a small glacier in sweden were computed for two melt seasons applying temperature index methods to a 30 m resolution grid for the melt component the classical degree day method yielded a good simulation of the seasonal patient of discharge but the pronounced melt induced daily discharge cycles were not captured modelled degree day factors calculated for every hour and each gridcell from melt obtained from a distributed energy balance model varied substantially both diurnally and spatially a new distributed temperature index model is suggested attempting to capture both the pronounced diurnal melt cycles and the spatial variations in melt due to the effects of surrounding topography this is accomplished by including a radiation index in terms of potential clear sky direct solar radiation and thus without the need for other data besides air temperature this approach improved considerably the simulation of diurnal discharge fluctuations and yielded a more realistic spatial distribution of melt rates the incorporation of measured global radiation to account for the reduction in direct solar radiation due to cloudiness did not lead to additional improvement in model performance

the california current system in the southern california bight and the santa barbara channel recent observations in the santa barbara channel and over the california cooperative oceanic fisheries investigations calcofi southern california grid are used to examine seasonal circulation patterns in and near the southern california bight defined as the region east of the santa rosa ridge and including the santa barbara channel poleward flow relative to 500 m is found throughout the bight in all seasons except for spring and all subregions except the western part of the santa barbara channel in spring there is equatorward flow throughout the bight at all depths to 500 m though it tends to be surface or midcolumn intensified equatorward flow offshore of the bight present in all seasons narrows and accelerates into a jet like feature and simultaneously moves close to the santa rosa ridge in summer current meter data from the eastern entrance to the santa barbara channel are consistent with the seasonal results from the calcofi data and further show an upward propagation of phase at annual period with a phase speed of 1 to 2 m d 1 comparison with the calcofi ship winds suggests that poleward flow in the bight may be the result of positive wind stress curl through a sverdrup balance though the observed transport is only about 75 of that expected from the curl amplitude equatorward flow in the bight may be the result of coastal upwelling though the transport is larger than expected from the relatively weak winds in the bight and the offshore extent of the equatorward flow is about 10 rossby radii farther than might be expected for linearized coastal upwelling equatorward flow outside the bight cannot be explained as a sverdrup flow because the wind stress curl is positive throughout most of the region upward propagation of phase and downward propagation of energy may be indicative of forcing by remote wind equatorward of the bight given the complexity of possible forcing mechanisms for circulation in and near the bight a model that includes effects of remote wind forcing ekman pumping and topography is needed to explain the observations in a satisfactory way

near surface trajectories off central and southern california the near surface circulation in the santa barbara channel and off the coast of central and southern california is described based on 20 releases of drifters drogued 1 m beneath the surface from 12 sites within the channel at bimonthly intervals this description includes small scale features of the circulation which are not part of descriptions based on moored observations or of the statistics of the drifter releases the eventual fate of drifters at long time intervals compared to the residence time in the channel about 7 days is also included in the channel the trajectories document a persistent cyclonic circulation with a typical recirculation period between 3 and 5 days in the spring currents near the mainland are weaker than near the channel islands and the overall flow is toward the southeast trajectories document the possibility for water parcels to leave the channel through the interisland passes in the late fall and winter a poleward flow with velocities often exceeding 0 5 m s 1 is confined within 20 km of the mainland between these two seasons the cyclonic tendency is enhanced although most of the drifters eventually migrate westward the trajectories of drifters released at the same time from sites only 20 km apart can be remarkably different once the drifters migrate out of the channel their trajectories can be grouped into a few patterns in spring and summer drifters tend to remain in the southern california bight their trajectories often remain close over extended periods as if they were caught in convergence zones in fall the drifters often are caught in a poleward current

spatio temporal variability of piezometric response on two steep alpine hillslopes information on the main drivers of subsurface flow generation on hillslopes of alpine headwater catchments is still missing therefore the dominant factors controlling the water table response to precipitation at the hillslope scale in the alpine bridge creek catchment northern italy were investigated two steep hillslopes of similar size soil properties and vegetation cover but contrasting topography were instrumented with 24 piezometric wells sixty three 63 rainfall runoff events were selected over three years in the snow free months to analyse the influence of rainfall depth antecedent moisture conditions hillslope topographic characteristics and soil depth on shallow water table dynamics piezometric response expressed as percentage of well activation and water peak magnitude was strongly correlated with soil moisture status as described by an index combining antecedent soil moisture and rainfall depth hillslope topography was found to be a dominant control only for the convex divergent hillslope and during wet conditions timing of water table response depended primarily on soil depth and topographic position with piezometric peak response occurring later and showing a greater temporal variability at the hillslope bottom characterized by thicker soil the relationship between mean hillslope water table level and standard deviation for all wells reflected the timing of the water table response at the different locations along the hillslopes the outcomes of this research contribute to a better understanding of the controls on piezometric response at the hillslope scale in steep terrain and its role on the hydrological functioning of the study catchment and of other sites with similar physiographic characteristics copyright 2014 john wiley sons ltd

diurnal period internal waves near point conception california diurnal period internal waves were observed near point conception california using an array of moorings extending 120 km along the inner shelf the waves have an along shelf coherence scale of at least 50 km and appear to propagate nearly straight onshore wave amplitudes vary over time depending on thermal stratification and the amplitude of the diurnal sea breeze oscillation barotropic tides and vorticity over the mid shelf are not correlated with internal wave amplitude large amplitude internal waves with supercritical froude numbers are observed in mid summer although such waves may drive vertical mixing and cross shelf transport of passive particles there is no significant correlation between wave amplitude and invertebrate settlement in the santa barbara channel

flow around a coastal bend a model of the santa barbara channel eddy a steady equatorward wind stress is applied over a two layer ocean infinitely deep lower layer west of an otherwise straight meridional coast with a right angle bend initial t 10 days response consists of an equatorward current kelvin wave that triggers a cyclone around the bend through viscous production and advection of vorticity a process akin to eddy shedding in flows without rotation the response at large times is governed by a kelvin wave forced by the equatorward weakening of the assumed positive wind stress curl which produces a poleward current near the coast application to the santa barbara channel cyclone is discussed and the cyclone formation process is further demonstrated with a three dimensional model with topography and stratification

a view of the 1993 1994 california current based on surface drifters floats and remotely sensed data near surface drifters were deployed in the california current system during the period 1993 1994 in order to study mean and eddy currents the deployment scheme allowed a 2 year period where data density was high enough to make meaningful estimates of eddy statistics and of seasonal mean currents and variances on a 5 grid eddy variability which tended to be isotropic was higher near the coast standard deviations around 0 2 m s 1 and decreased offshore down to 0 1 m s 1 seasonal mean surface flow west of california was southward during all seasons if a davidson current existed during 1993 1995 it was probably either short lived or only found closer to the coast than our study area i e within 100 150 km of shore in some cases drifter populations within a discrete feature were high enough to allow some detailed resolution of its behavior we note a tendency for individual eddies which can last for up to 3 5 months to drift westward at rates of o 5 km day 1 not all eddies in the region are surface intensified there is clear evidence for at least the occasional presence of a thin meandering southward jet in the region that can be 1000 km or more long this jet can be identified with that found in the coastal transition zone program in association with cool filaments the jet appears to become broader and slower south of point conception we hypothesize on the basis of others results as well as ours that the eddies that are strongest at the surface result primarily from instabilities on a southward alongshore mean current and that eddies that are maximal at depth are spawned by the northward undercurrent

large scale response to atmospheric forcing of shelf currents and coastal sea level off the west coast of north america may july 1981 and 1982 the response of alongshore currents v over the continental shelf and of coastal sea level along the pacific coast of north america to atmospheric forcing on large alongshore scales 100 2000 km during may july 1981 coastal ocean dynamics experiment code 1 and may july 1982 code 2 has been studied using sea level and wind measurements from coastal stations and buoys between 33 n and 48 n and using current measurements from five locations between 35 n and 48 n characteristics of the large scale response of v and to fluctuations in the alongshore component of the wind stress varied with latitude and with year in relation to variations in in 1981 large scale fluctuations were coherent within but not between separate domains north and south of 42 n in 1982 large scale coherent fluctuations were found only in a northern domain that extended much farther south to near 37 n accordingly in 1981 alongshore current v fluctuations from 39 n code were coherent with v from 35 n while in 1982 v fluctuations from 39 n were coherent with those north to 48 n in 1981 the northern domain fluctuations were forced by between 42 n and 45 n with southern domain forcing at 35 36 n in 1982 northern domain fluctuations were forced by over a region of much larger along shore extent 37 48 n high values of space lagged coherences between v and y y is the alongshore coordinate indicate that v at 39 n was strongly wind driven maximum squared coherences of v versus y are found with to the south by 100 300 km for low frequencies 0 23 cpd in 1981 0 14 cpd in 1982 and with from near local stations at higher indicating the importance of remote forcing at low frequencies and local forcing at high frequencies the response of v to y at 35 n and 43 n was more complicated but evidence for strong wind forcing is found in several frequency bands for v at 43 n during 1981 and 1982 and at 35 n during 1981 at 48 n v was forced in 1982 for 0 18 cpd by from locations 300 1400 km to the south

families of miocene monterey crude oil seep and tarball samples coastal california biomarker and stable carbon isotope ratios were used to infer the age lithology organic matter input and depositional environment of the source rocks for 388 samples of produced crude oil seep oil and tarballs to better assess their origins and distributions in coastal california these samples were used to construct a chemometric multivariate statistical decision tree to classify 288 additional samples the results identify three tribes of 13c rich oil samples inferred to originate from thermally mature equivalents of the clayey siliceous carbonaceous marl and lower calcareous siliceous members of the monterey formation at naples beach near santa barbara an attempt to correlate these families to rock extracts from these members in the nearby cost continental offshore stratigraphic test ocs cal 78 164 well failed at least in part because the rocks are thermally immature geochemical similarities among the oil tribes and their widespread distribution support the prograding margin model or the banktop slope basin model instead of the ridge and basin model for the deposition of the monterey formation tribe 1 contains four oil families having geochemical traits of clay rich marine shale source rock deposited under suboxic conditions with substantial higher plant input tribe 2 contains four oil families with traits intermediate between tribes 1 and 3 except for abundant 28 30 bisnorhopane indicating suboxic to anoxic marine marl source rock with hemipelagic input tribe 3 contains five oil families with traits of distal marine carbonate source rock deposited under anoxic conditions with pelagic but little or no higher plant input tribes 1 and 2 occur mainly south of point conception in paleogeographic settings where deep burial of the monterey source rock favored petroleum generation from all three members or their equivalents in this area oil from the clayey siliceous and carbonaceous marl members tribes 1 and 2 may overwhelm that from the lower calcareous siliceous member tribe 3 because the latter is thinner and less oil prone than the overlying members tribe 3 occurs mainly north of point conception where shallow burial caused preferential generation from the underlying lower calcareous siliceous member or another unit with similar characteristics in a test of the decision tree 10 tarball samples collected from beaches in monterey and san mateo counties in early 2007 were found to originate from natural seeps representing different organofacies of monterey formation source rock instead from one anthropogenic pollution event the seeps apparently became more active because of increased storm activity

west florida shelf mean circulation observed with long term moorings 1 the mean circulation on the west florida continental shelf is described using long term current measurements bounded by the florida peninsula to the east and the gulf of mexico to the west the west florida continental shelf mean flow is oriented approximately along isobath and southward the mean velocity vectors veer systematically with depth shoreward over shallow water and seaward over deeper water this polarization change implies that the mean flow is upwelling over shallow water and downwelling seaward from the inner shelf such a well organized three dimensional coastal ocean circulation pattern revealed by an unprecedented set of observations and explained on the basis of wind forcing and density field adjustment has important implications for both fisheries and red tide occurrences

errors in daily ablation measurements in northern greenland 1993 94 and their implications for glacier climate studies ablation climate studies were made at two locations in northern green land in the summers of 1993 and 1994 respec tively daily ablation ii as measured at ten stakes within a small area and the data were compared with each other to detect gross errors for example high deviations for data taken on the same day or low cor rela tions between data series at differ ent stakes indicate erroneous data a fter cl iscard i ng data for one stake in 1993 and t wo stakes in 1994 random errors in daily ablation data for individ ual stakes arc 5 kg m 2 d i which is further reduced to only about 2 kg m 2 d 1 by averag ing over eight or nine stakes random errors in cal culated energy bala nces using the pres ent abla tion data are much imover than found in earlier studies in vest greenland where ablation was only measured on three stakes without any attem pt to detect gross errors aside from day to day errors there arc 10 diffe rences in mca n ablation at different sta kes which are probably caused by small s cal e variations in surface albedo such inters take diffe rences gi e 10 uncertainty in positive degree day faetors which arc 9 8 0 9 and 5 9 0 6 kg m 2 d 1 deg 1 for the two sites

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

the spatial scales distribution and intensity of natural marine hydrocarbon seeps near coal oil point california natural hydrocarbon seepage from marine environments is an important source of methane and other gases to the atmosphere quantifying this flux is necessary for constraining global budgets and understanding local air pollution sources a field of strong hydrocarbon seepage offshore of coal oil point near santa barbara california produces extensive areas of bursting bubbles at the sea surface an instrumented buoy was deployed in the coal oil point field to measure directly the atmospheric gas flux from three seeps of varying size and intensity spatial scales of continuity of the seeps quantified by semivariograms are small ranging from 1 to about 9 m such that flux values on larger scales are uncorrelated these de correlation scales are comparable to the horizontal extents of individual bubble plumes estimated visually at the sea surface semivariograms for each seep are used in an ordinary kriging procedure to interpolate flux measurements onto a regular grid and produce objective maps of the spatial distribution of flux spatial integrals yield total flux estimates from the three seeps of 7400 m 3 day 1 which amount to 4 13 of the total flux from the coal oil point field based on estimates from previous studies

coastal water circulation patterns around the northern channel islands and point conception california abstract the northern channel islands in california host multiple marine protected areas containing kelp forest ecosystems little is known about the water circulation onshore of the 20 m isobath we use water velocity recorded at 21 sites near the 15 m isobath at the islands and mainland during 1999 2012 to describe the water circulation on time scales of days to months the mean circulation is eastward or weak at the islands but poleward along the mainland speeds 0 10 cm s 1 the subinertial frequency along shelf flow is surface intensified and reverses direction on time scales of days in summer the flow becomes more poleward throughout the region the mean cross shelf flow profiles are strikingly similar at most sites with flow speeds 1 2 cm s 1 the mean flow near bottom in the vicinity of the kelp forests is offshore the time varying two layered response to wind is stronger up to 6 cm s 1 the flushing time of the shelf onshore of the 15 m isobath is short at most 2 dy at a few sites exposed to the prevailing wind up to 60 of the velocity variance is predictable from wind measured in the santa barbara channel in the lee of point conception or at the islands however regional wind explains little of the velocity variance during weak winds the velocity at some mainland but not island sites responds to pressure gradients measured along the mainland coast these pressure gradients are associated with local wind relaxations at pt conception not with remotely generated coastal trapped waves

the evolution and depth structure of shelf and slope temperatures and velocities during the 1997 1998 el nino near point conception california abstract moored survey and drifter observations are used to describe the evolution of temperature sea level velocity and salinity from 1997 to 1998 over the california shelf between san luis obispo bay and the eastern entrance to the santa barbara channel the dominant event during this time was the 1997 1998 el nino its relation to background seasonal and interannual variability depended on which property is considered subsurface temperature and local sea level showed extreme anomalies between march 1997 and october 1998 three distinct peaks occurred the first two are associated with the regional response to el nino while the cause of the third remains unclear the first peaked in june 1997 and decayed until august the main el nino peak reached maximum amplitude between november 1997 and january 1998 after the collapse of the regional el nino anomaly in february 1998 a final peak occurred locally during the summer of 1998 the central result presented here concerns the spatial structure of temperature during these events the initial peak was surface intensified and was barely detectable at 45 m its amplitude varied with position along the coast decaying with distance north the main peak showed a strong signal down to at least 200 m the amplitude and timing of temperature anomalies during this event were depth dependent the largest absolute amplitudes relative to seasonal cycles were in excess of 4 c and occurred between 45 and 65 m depth the anomalies reached their maximum values at later time with increasing depth between october 1997 and january 1998 the amplitude of this main peak was comparable at all mooring sites the final peak in august 1998 had a comparable amplitude at all mooring sites to a depth of 100 m temperature increases during the three events were accompanied by a corresponding rise in sea level the el nino signals in currents and salinity are more difficult to distinguish from background variability than those in temperatures and sea level however stronger than average poleward flow was observed at the eastern entrance to the santa barbara channel between 5 and 100 m depth for most of 1997 and there are indications for greater than usual poleward flow over the santa maria basin in fall 1997 surface drifter evidence although qualitative also suggests greater than usual poleward displacement in november 1997 relative to other years along with increased temperature survey observations of salinity suggest changes to the regional temperature salinity relation during november 1997 with greater than usual salinity at temperatures below 12 c

threshold relations in subsurface stormflow 2 the fill and spill hypothesis analysis of subsurface stormflow from 147 storms at the 20 m long trench in the panola mountain research watershed by tromp van meerveld and mcdonnell 2006a showed that there was a distinct 55 mm precipitation threshold for significant subsurface stormflow production this second paper in the series investigates the processes responsible for this threshold response we installed a dense spatial array of maximum rise crest stage gauges and recording wells on the hillslope and studied the temporal and spatial patterns of transient saturation at the soil bedrock interface and its relation to subsurface stormflow measured at the trench face results show that while transient groundwater developed on parts of the hillslope during events smaller than 55 mm it was not until more than 55 mm of rain fell before bedrock depressions on the hillslope were filled water spilled over microtopographic relief in the bedrock surface and the subsurface saturated areas became connected to the trench when connectivity was achieved the instantaneous subsurface stormflow rate increased more than fivefold compared to before the subsurface saturated areas were connected to the trench face total subsurface stormflow was more than 75 times larger when connectivity was achieved compared to when connectivity was not achieved the fill and spill hypothesis presented in this paper is a process explanation for the observed threshold behavior of tromp van meerveld and mcdonnell 2006a thereby linking patterns and processes

intraseasonal oscillations in sea level along the west coast of the americas abstract hourly observations of coastal sea level at stations from peru to british columbia are analyzed for low frequency content a space time contour plot of sea level from four years of data during the 1971 75 period shows the meridional structure of the seasonal cycle and interannual variability associated with the 1972 73 el nino oscillations with intraseasonal periods of 36 73 days are also evident coherent over alongshore distances of several thousand kilometers further investigation using spectral methods and empirical orthogonal function analysis in the frequency domain reveals in particular that intraseasonal sea level variability has a peak in spectral density along the coasts of south america central america and mexico with high coherence from near the equator tumaco 2 n north to central california 34 n and south to at least callao 12 s phase propagation north of the equator is poleward at 150 200 kilometers day atmospheric pressure alongshore wind stress and wind stress cu

groundwater dynamics in a till hillslope flow directions gradients and delay knowledge of groundwater dynamics is important for the understanding of hydrological controls on chemical processes along the water flow pathways to increase our knowledge of groundwater dynamics

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 relaxations and poleward flow events in a coastal upwelling system on the central california coast 1 when upwelling favorable winds weaken or relax in coastal upwelling systems prevailing equatorward currents often weaken and then reverse to form propagating poleward currents here the statistics of wind relaxations and poleward flow events along the south central california coast are derived using meteorological and oceanographic times series during 2000 2006 over the 7 year record 169 wind relaxations were observed about 1 every 2 weeks and 127 of these were followed by poleward flow events thermistor moorings and current profilers along the 15 m isobath at alegria point arguello point purisima and point sal recorded the poleward flows the poleward flows propagate northward at 10 30 km d 1 and appear as sequential temperature increases at the moorings wind relaxations occur throughout the year but are most frequent in september and least frequent in april when upwelling winds are strong and persistent poleward flows follow wind relaxations frequently during may through november and rarely in december and january sea level differences between santa monica and port san luis california decreased as winds relaxed consistent with forcing by alongshore pressure gradients temperature distributions at point arguello point purisima and point sal were skewed toward higher values because of the poleward flows the alongshore distance traveled by the poleward flows increased with duration of the wind relaxations and magnitudes of alongshore temperature and sea level differences prior to the relaxations

melt water driven stream and groundwater stage fluctuations on a glacier forefield dammagletscher switzerland in many mountain regions large land areas with heterogeneous soils have become ice free with the ongoing glacier retreat on these recently formed proglacial fields the melt of the remaining glaciers typically drives pronounced diurnal stream level fluctuations that propagate into the riparian zone this behaviour was measured on the damma glacier forefield in central switzerland with stage recorders in the stream and groundwater monitoring wells along four transects in spite of the large groundwater stage variations radon measurements in the near stream riparian zone indicate that there is little mixing between stream water and groundwater on daily time scales at all four transects including both losing and gaining reaches the groundwater level fluctuations lagged the stream stage variations and were often damped with distance from the stream similar behaviours have been modelled using the diffusion equation in coastal regions influenced by tidal sea level variations we thus tested the ability of such a model to predict groundwater level fluctuations in proglacial fields the model reproduced several key features of the observed fluctuations at three of four locations although discrepancies also arise due to non representative input data and model simplifications nevertheless calibration of the model for the individual transects yielded realistic estimates of hydraulic diffusivities between the stream and groundwater monitoring wells we conclude that studying diurnal groundwater fluctuations can provide important information about the subsurface hydrology of alpine watersheds dominated by glacier melt copyright 2012 john wiley sons ltd

constraints on average taiwan reference moho discontinuity model receiver function analysis using bats data summary by analysing teleseismic waveform data we propose a large scale taiwan reference moho discontinuity model trmdm through coherent stacking and h analysis of receiver functions rfs tectonic structural features are determined from accurate crustal thickness h and reliable vp vs ratio consequently poisson s ratio estimations for taiwan the best estimated regional average moho depth is 33 5 2 9 km noted is a westward crustal thinning from 39 3 0 km in eastern taiwan to 30 1 5 km in southeastern china the averaged moho depth is 23 0 2 5 km in northern taiwan and increases to 33 5 2 0 km in the south the markedly thin crust and high vp vs ratio in northern taiwan are mainly associated with backarc opening and magmatic activities based on h estimations and associated seismicity patterns beneath suang long sslb and adjacent four stations we propose two moho reference models that exhibit distinctive crustal thickening in central taiwan the spatial variations of crustal thickness models show strong lateral change in the moho topography the thick crust in the south thin crust in the north and transition in central taiwan mark the different tectonic units between the subduction wedge and the collision prism onshore in view of the following list of constraints thicker crust in the south than in the north eastward crust thickening significant moho depth changes clear 9 11 s subcrustal boundaries from five stations the compelling thickening of crust and upper mantle beneath the central mountain belt seismicity patterns with the absence of mantle earthquake in the wadatibenioff zone regional geological features the occurrence of the inland chi chi earthquake the compelling low at yulb 1 58 0 13 that may extend to central taiwan at sslb 1 59 0 23 relatively thick crust at yulb 39 5 1 6 km and sslb 40 5 1 3 km or 52 5 1 5 km and finally the apparent horizontal offset between highest yu shan mountain and the deepest moho at sslb we are able to suggest that the initial subduction of the eurasian plate occurred in southern taiwan and most likely extended to the transition zone in central taiwan although the current rf study is limited by large interstation distance our analysis provides more notable constraints than previous studies to explicitly determine the characteristic features of moho discontinuity this detailed approach means that rather than treating the tectonic framework as a whole heterogeneous lithospheric feature clear moho boundary geometry variations indicate that active orogenic processes and differential tectonic stress loading create separate and complex crustal and subcrustal to upper mantle structural features caused by the arc continent collision

large scale structure of the spring transition in the coastal ocean off western north america past measurements off the coast of central oregon and washington have shown that the rapid change from northward monthly mean winter winds to southward summer winds forces a spring transition of the coastal ocean sea levels and temperatures drop and mean surface currents shift from northward to southward current and water temperature data from 35 n to 48 n from 1981 and 1982 and sea level and wind stress data from 1971 1975 and 1980 1983 show the transition to have a large alongshore scale typically 500 to 2000 km the large scale wind stress appears to be the forcing mechanism at latitudes north of approximately 37 n south of 37 n sea level usually falls more gradually before the northern transition event both wind and sea level events generally progress from south to north over a 3 to 10 day period but this is not always true several aspects of the spring transition reflect coastal trapped wave dynamics previous studies at 45 n found persistent vertical shear of the southward summer current associated with a cross shelf density gradient during 1982 the shear and the density front develop over the shelf break immediately after the transition at 43 n and to the south but they are much less persistent than at 48 n the stronger winds between 38 n and 42 n and the narrower shelf result in an offshore displacement of the density front and vertical shear past the shelf break leaving the water over the shelf less stratified and more subject to barotropic reversals of the current than that farther north where the front stays closer to the coast

the intraseasonal oscillation in eastern pacific sea levels how is it forced abstract daily sea level and surface winds at eastern pacific shore locations and equatorial islands together with gridded five day averages of 850 mb winds have been analyzed for the 1979 84 period to determine how the 40 60 day intraseasonal oscillation of eastern pacific sea levels is forced as described by spillane et al for 1971 75 the oscillation was also present in 1980 84 from callao peru to san francisco with maximum energy near 52 57 days and band limits of 43 and 65 days during 1980 84 there was no evidence for forcing of the large scale oscillation in the eastern pacific although a local contribution of forcing was superimposed on the remote signal at the california stations interannual fluctuations in amplitude were evident in the sea level time series consistent with those of the corresponding wind oscillation in the western equatorial pacific the oscillation was best developed in both variables in 1980 82 and became weak or nonexistent during the recovery phase of the 1982 83 e

sensitivity of coastal currents near point conception to forcing by three different winds ecmwf coamps and blended ssm i ecmwf buoy winds previous observational and modeling studies have indicated the importance of finescale winds in determining the circulation near point conception in the santa maria basin smb and the santa barbara channel sbc california there has not been a systematic attempt however to analyze and quantify the sensitivity of the near surface circulation to different wind data here a regional circulation model of the smb and sbc is driven using three wind datasets the european centre for medium range weather forecasts ecmwf 110 km 110 km horizontal grid the coupled ocean atmosphere mesoscale prediction system coamps 9 km 9 km horizontal grid and a blended wind product that combines special sensor microwave imager ssm i ecmwf and buoy and coastal wind data and that is referred to as seb a springtime period march may 1999 in which equatorward wind dominates and wind stress curls are strong is chosen for the study two groups of experiments are conducted with and without assimilating moored temperature observations the focus is on long time scales of greater than weeks and on mean currents comparisons between these experiments and between model and observation show that the circulation driven by the ecmwf wind is much weaker than that by the other two winds on the other hand the seb dataset shows locally intensified wind stress curls behind capes and coastal bends whereas these wind stress curls are weak in coamps it is found that these small scale variations in the wind field force alongshore inhomogeneous pressure gradients that in turn can significantly affect the near coast currents the result is that modeled currents forced by seb agree better with observations than do those produced by coamps empirical orthogonal function analyses were conducted on the near surface currents sea level wind and wind stress curl the mode 1 current 40 is unidirectional i e generally equatorward or poleward and correlates well with the mode 1 wind 90 the mode 2 current 20 is cyclonic in the sbc and poleward inshore and equatorward offshore in the smb it correlates well with mode 1 sea level 70 which suggests that mode 2 currents are driven by the pressure gradient it is significant that neither mode 2 current nor mode 1 sea level correlates well with mode 1 wind stress curl 70 rather they correlate well with the time integral of the mode 1 wind stress curl these conclusions support a previous theoretical idea that cyclonic circulation in the sbc and the inshore currents of the smb are both driven by alongshore pressure setup induced by the time integral of the wind stress curl rather than by the wind stress curl itself this idea of a pressure setup is consistent with the differences found between the currents driven by coamps and seb winds

effects of small scale wind on coastal upwelling with application to point conception a three dimensional limited area ocean general circulation model is used to study the response of the coastal ocean to small scale wind forcing the model considers an idealized forcing of a semi infinite upwelling favorable wind with a large positive wind curl at one end such a wind pattern is commonly found in the vicinity of capes and points where the synoptic scale wind is disturbed by coastal mountain ranges the model study includes both process and hindcast studies the process study considers the upwelling spinup and relaxation driven by a positive wind curl it also examines the model sensitivity to wind patterns and an external pressure force the model results show that a strong poleward alongshore pressure gradient is set up by a positive wind curl this pressure force drives an inshore poleward current into the upwelling region during active wind forcing and it causes a surge of warm water into the upwelling zone during wind relaxation the hindcast study is applied to the 1983 organization of persistent upwelling structures opus observations near point conception off central california the simulation uses an idealized geometry but with observed winds during opus a sudden reversal of the surface equatorward currents occurred in the midst of a steady upwelling favorable wind this unexpected coastal flow feature was faithfully reproduced in the model simulation

assimilation of surface velocity data into a primitive equation coastal ocean model summer of 1998 are 0 42 and 0 78 respectively demonstrating the effectiveness of the das our estimates of the error covariances are shown to be appropriate through a series of objective statistical tests analysis of the term balances of the model equations show that the dominant modeled dynamical balances are preserved by the das and that uncertainties in the spatial variability of the wind forcing are likely to be one source of model error by varying the relative magnitudes of the estimated forecast and observation error covariances the das is shown to be most effective when approximately 80 of the analysis is made up of the model solution index terms 4263 oceanography general ocean prediction 4219 oceanography general continental shelf processes 4255 oceanography general numerical modeling 3337 meteorology and atmospheric dynamics numerical modeling and data assimilation 4516 oceanography physical eastern boundary currents 4594 oceanography physical instruments and techniques keywords practical data assimilation numerical modeling upwelling highfrequency radar data

characteristic patterns of shelf circulation at the boundary between central and southern california 1 the coastal circulation in the santa barbara channel sbc and the southern central california shelf is described in terms of three characteristic flow patterns the upwelling pattern consists of a prevailing equatorward flow at the surface and at 45 m depth except in the area immediately adjacent to the mainland coast in the sbc where the prevailing cyclonic circulation is strong enough to reverse the equatorward tendency and the flow is toward the west in the surface convergent pattern north of point conception the surface flow is equatorward while the flow at 45 m depth is poleward east of point conception along the mainland coast the flow is westward at all depths and there results a convergence at the surface between point conception and point arguello with offshore transport over a distance on the order of 100 km beneath the surface layer the direction of the flow is consistently poleward the relaxation pattern is almost the reverse of the upwelling pattern with the exception that in the sbc the cyclonic circulation is such that the flow north of the channel islands remains eastward although weak the upwelling pattern is more likely to occur in march and april after the spring transition when the winds first become upwelling favorable and while the surface pressure is uniform the surface convergent pattern tends to occur in summer when the wind is still strong and persistently upwelling favorable and the alongshore variable upwelling has build up alongshore surface pressure gradients the relaxation pattern occurs in late fall and early winter after the end of the period of persistent upwelling favorable winds

wind relaxation and a coastal buoyant plume north of pt conception ca observations simulations and scalings in upwelling regions wind relaxations lead to poleward propagating warm water plumes that are important to coastal ecosystems the coastal ocean response to wind relaxation around pt conception ca is simulated with a regional ocean model roms forced by realistic surface and lateral boundary conditions including tidal processes the model reproduces well the statistics of observed subtidal water column temperature and velocity at both outer and inner shelf mooring locations throughout the study a poleward propagating plume of southern california bight water that increases shelf water temperatures by 5 c is also reproduced modeled plume propagation speed spatial scales and flow structure are consistent with a theoretical scaling for coastal buoyant plumes with both surface trapped and slope controlled dynamics plume momentum balances are distinct between the offshore 30 m depth region where the plume is surface trapped and onshore of the 30 m isobath within 5 km from shore where the plume water mass extends to the bottom and is slope controlled in the onshore region bottom stress is important in the alongshore momentum equation and generates vertical vorticity that is an order of magnitude larger than the vorticity in the plume core numerical experiments without tidal forcing show that modeled surface temperatures are biased 0 5 c high potentially affecting plume propagation distance and persistence

shallow groundwater surface water interactions in pond peatland complexes along a boreal plains topographic gradient shallow pond peatland complexes are important water resources and waterbird habitat on the boreal plains of canada and are potentially threatened by accelerated resource development we examined two shallow pond peatland complexes located in contrasting topographic positions within a clay rich till region one on a moraine and one on a lowland clay plain to evaluate the influence of landscape position on wetland groundwater surface water interactions hydrologic function and potential response to disturbance hydrometric and geochemical measurements indicated that precipitation and evaporation dominated the annual water balance of both ponds forested mineral uplands adjacent to the pond peatland complexes contributed no runoff inputs small recharge rates 5 mm year 1 from the ponds through low permeable clay to the underlying aquifer were measured at both topographic locations shallow groundwater fluxes to from the pond were controlled by water storage in and exchange with the adjacent riparian peatlands shallow groundwater fluxes may have contributed as much as 23 of inputs and outputs and influenced pond chemistry and permanence shallow groundwater exchange between the pond and adjacent peatlands varied seasonally and differed between the moraine and lowland complex groundwater flow reversals occurred around the entire perimeter of the moraine pond recharge from the moraine pond to the peatland during dry periods was off set by discharge to the pond from the peatland during wet periods in contrast shallow groundwater flow through conditions were observed at the lowland pond for most of the study however during a high rainfall event a groundwater flow reversal within the outflow peatland initiated discharge back into the pond these results suggest that the hydrologic regimes of some pond peatland complexes in clay rich till within the boreal plains will be more sensitive to local scale disturbances that impact flow dynamics and storage of near shore peatlands rather than larger scale disturbances of mineral upland regions

a poleward jet and an equatorward undercurrent observed off oregon and northern california during the 1997 98 el nino abstract the timing and intensity of the effects of the 1997 98 el nino on sea surface temperature sst and coastal sea level along the us west coast are examined using in situ time series measurements and the effects on upper ocean currents on the continental shelf and slope off oregon and northern california are examined using repeated shipborne adcp transects a mid shelf mooring off newport oregon and an hf surface current radar an initial transient positive anomaly was observed in both adjusted sea level and sst during may june 1997 followed by anomalously high coastal sea levels generally strongest during september 1997 through february 1998 and abruptly returned to normal in late february 1998 and by positive temperatures anomalies over the mid shelf that persisted longer into april 1998 low frequency coastal sea level anomalies propagated poleward at 2 1 m s poleward flow over the shelf and slope was enhanced at most depths during the el nino compared with following years northward currents in the upper 12 m over the continental shelf off newport oregon averaged 13 7 cm s stronger during august 1997 through february 1998 than during the same period the following year enhanced poleward flow was present at all latitudes sampled during november 1997 and february 1998 particularly over the continental slope these transects also provided clear views of a fall winter equatorward undercurrent which was both strongest and had the most alongshore similarity of form during the enso finally subsurface intensified anticyclonic eddies originating in the poleward undercurrent appear to be a recurrent feature of the circulation off newport late in the upwelling season

a forcing mechanism for the poleward flow off the southern california coast it is shown that when the wind distribution along a coast is anisotropic such that its cross shore scale is smaller than its alongshore scale the coastal sea level or the upper layer anomoly a of an ocean forced by both wind and wind curl is governed by a modified nondimensionalized kelvin wave equation a t a y k0 0 y t k1 y dtl where k0 and k1 are wind stress and wind stress curl at the coast respectively y is the alongshore distance and t is the time numerical experiments from a simple reduced gravity type with idealized forcing and coastline to a three dimensional primitive equation model with a realistic coastline bottom topography of the southern california bight and the santa barbara channel and observed wind stresses were carried out to show that the observed near coast near surface poleward flow in the region is primarily forced by the equatorward weakening of the wind curl k1 y 0 in the bight beta provides natural damping by weakening and widening the current through westward propagating rossby waves and causes the current to lead the coastal pressure field by 1 2 months which improves the agreement with observations of the phasing of the modeled currents but is otherwise not required in forcing the poleward flow

lagrangian observations of inner shelf motions in southern california can surface waves decelerate shoreward moving drifters just outside the surf zone abstractthis study explores eulerian and lagrangian circulation during weak winds at two inner shelf locations off the southern california coast where the shoreline shelf wind and wave characteristics differ from those in previous studies in agreement with recent observational studies wave driven eulerian offshore flow just outside the surf zone referred to as undertow is a substantial component of the net cross shore circulation during periods of weak winds drifter observations show onshore surface flow likely due to light onshore winds and a consistent decrease in onshore velocity of roughly 4 cm s 1 within a few hundred meters of the surf zone undertow is examined as a possible explanation for the observed lagrangian decelerations model results suggest that even when waves are small undertow can decrease the velocity of shoreward moving drifters by 2 cm s 1 roughly half the observed deceleration the coastal boundary condition also has the potential to contribute to the observed deceler

inner shelf intrusions of offshore water in an upwelling system affect coastal connectivity 1 poleward warm water flows around point conception are an important transport mechanism linking biogeographic provinces along central california these flows are initiated by relaxation of upwelling winds the intensity and duration of upwelling is an important driver of how far north warm water penetrates against the prevailing surface currents in this paper we present evidence of offshore surface water intrusions to the inner shelf 130 km north of point conception near cambria california satellite observations show that the intrusions originate as eddies generated offshore along the upwelling front these eddies may form as submesoscale instabilities or by interaction of upwelling centers with offshore waters the intrusions move southern waters to the central california inner shelf further northward than is typical for a coastal relaxation plume and therefore inner shelf connectivity and ecology may be governed over timescales and distances longer than those set by the intermittent relaxation of upwelling winds

a multi method field experiment to determine local groundwater flow in a glacier forefield we implemented multiple independent field techniques to determine the direction and velocity of groundwater flow at a specific stream reach in a glacier forefield time lapse experiments were conducted using two electrical resistivity tomography ert lines installed in a cross pattern a circular array of groundwater tubes was also installed to monitor groundwater flow via discrete salt injections both inter borehole and ert results confirmed this stream section as a losing reach and enabled quantification of the flow direction both techniques yielded advection velocities varying between 5 7 and 21 8 m day estimates of groundwater flow direction and velocity indicated that groundwater infiltrates from the stream nearby and not from the adjacent lateral moraine groundwater age estimated from radon concentration measurements supported this hypothesis despite uncertainties inherent to each of the methods deployed the combination of multiple field techniques allowed drawing consistent conclusions about local groundwater flow we thus regard our multi method approach as a reliable way to characterize the two dimensional groundwater flow at sites where more invasive groundwater investigation techniques are difficult to carry out and local heterogeneities can make single measurements unreliable copyright 2014 john wiley sons ltd

landscape controls on the hydrology of stream riparian zones abstract increased knowledge of hydrology is essential to an understanding of the water quality function of stream riparian zones we examined the effect of upland surficial aquifer size topography and riparian sediment lithology on the subsurface hydrology of eight riparian sites on glacial till and outwash landscapes in southern ontario canada riparian sites had a permanent subsurface hydrologic connection to the adjacent upland in landscapes where upland permeable sediment depths were 2 15 m in contrast a hydrologic connection was absent in summer and autumn at riparian sites with 5 where the riparian zone was level to gently sloping

on the three dimensional propagation of stationary waves abstract a locally applicable nonzonally averaged conservation relation is derived for quasi geostrophic stationary waves on a zonal flow a generalization of the eliassen palm relation the flux which appears in this relation constitutes it is argued a useful diagnostic of the three dimensional propagation of stationary wave activity this is illustrated by application to a simple theoretical model of a forced rossby wave train and to a northern hemisphere winter climatology results of the latter procedure suggest that the major forcing of the stationary wave field derives from the orographic effects of the tibetan plateau and from nonorographic effects diabatic heating and or interaction with transient eddies in the western north atlantic and north pacific oceans and siberia no evidence is found in the data for wave trains of tropical origin forcing by the orographic effects of the rocky mountains seems to be of secondary importance

seasonal cycles of currents temperatures winds and sea level over the northeast pacific continental shelf 35 n to 48 n seasonal cycles of coastal wind stress adjusted sea level asl shelf currents and water temperatures off the west coast of north america 35 n to 48 n are estimated by fitting annual and semiannual harmonics to data from 1981 1983 longer records 9 34 years of monthly asl indicate that these two harmonics adequately represent the long term monthly average seasonal cycle and that the current measurement period is long enough to estimate the seasonal cycles we characterize the differences between fall winter and spring summer as follows for fall winter monthly mean winds north of 35 n are northward for 3 6 months longer in the north than in the south south of 35 n the mean winds are near zero or weakly southward monthly mean alongshore currents are northward over midshelf and shelf break at all locations sampled at depths of 35 m and deeper and are associated with high coastal sea levels and relatively warm water temperatures for spring summer monthly mean wind stresses are southward at all latitudes for 3 6 months longer in the south than in the north sea levels are low and water temperatures are relatively cool monthly mean currents at 35 m depth over the shelf are southward for 1 6 months longer at the shelf break than over midshelf and longer in the north than in the south while the deeper currents are less southward or northward the magnitudes of the seasonal cycles of all variables are maximum between approximately 38 n and 43 n generally decreasing slightly to the north and greatly to the south at each location the seasonal cycle of the alongshore current from 35 m depth at midshelf leads the sea level slightly and both lead the wind stress and temperatures by 1 2 months the seasonal cycles of all variables show a south to north progression south leads north by 1 2 months at 48 n annual mean currents at 50 m depth over the shelf break oppose the annual mean wind northward wind and southward current similarly at 35 n annual mean currents at 35 m depth over both midshelf and shelf break are opposed to the annual mean wind southward wind and northward current from 35 n to 43 n both summer and winter regimes are dominated by strongly fluctuating currents

snow depth derived from passive microwave remote sensing data in china in this study we report on the spatial and temporal distribution of seasonal snow depth derived from passive microwave satellite remote sensing data e g smmr from 1978 to 1987 and smm i from 1987 to 2006 in china we first modified the chang algorithm and then validated it using meteorological observation data considering the influences from vegetation wet snow precipitation cold desert and frozen ground furthermore the modified algorithm is dynamically adjusted based on the seasonal variation of grain size and snow density snow depth distribution is indirectly validated by modis snow cover products by comparing the snow extent area from this work the final snow depth datasets from 1978 to 2006 show that the interannual snow depth variation is very significant the spatial and temporal distribution of snow depth is illustrated and discussed including the steady snow cover regions in china and snow mass trend in these regions though the areal extent of seasonal snow cover in the northern hemisphere indicates a weak decrease over a long period there is no clear trend in change of snow cover area extent in china however snow mass over the qinghai tibetan plateau and northwestern china has increased while it has weakly decreased in northeastern china overall snow depth in china during the past three decades shows significant interannual variation with a weak increasing trend

a global el nino southern oscillation wave in surface temperature and pressure and its interdecadal modulation from 1900 to 1997 zonal wavenumber frequency spectra of sea surface temperature sst anomalies along the equator in the indo pacific basin for the 98 years from 1900 to 1997 and of surface temperature st and sea level pressure slp anomalies extending around the globe along 10 n for the 48 years from 1950 to 1997 display significant peak spectral energy density for standing and eastward propagating waves of 3 7 year periods and 120 360 zonal wavelengths the global standing wave is the familiar southern oscillation but the global propagating wave represents a new paradigm for the el nino southern oscillation enso global distributions of the phase velocities for this global enso wave finds covarying slp and st anomalies propagating eastward along the mean path of the intertropical convergence zone itcz with the global zonal wavenumber 1 2 component taking 4 6 years to cross the tropical indian pacific and atlantic oceans at a zonal average speed of 90 60 longitude per year along this path the interannual sst and slp anomalies are directly out of phase since thermocline depth anomalies underneath the itcz in the pacific ocean propagate westward white et al 1985 we view the global enso wave as a slow coupled sst wave trapped onto the itcz separating the global enso wave from the southern oscillation using complex empirical orthogonal function analysis finds the amplitude of the propagating wave to be half that of the standing wave with the former latter accounting for one third two thirds of the interannual variability in nino 3 sst and slp indices during the 1980s the global enso wave is shown to be responsible for the eastward propagation of covarying zonal surface wind and thermocline depth anomalies across the equatorial pacific ocean and through this mechanism is able to influence both the phasing and intensity of el nino examining the persistence of the global enso wave from 1900 to 1997 finds it and the intensity of el nino in the eastern equatorial pacific ocean modulated by interdecadal change both were strong weak or absent during decades of global tropical cooling warming

the propagating response of coastal circulation due to wind relaxations along the central california coast 1 following relaxations of prevailing upwelling favorable winds warm waters from the santa barbara channel propagate poleward around point conception and along the south central california coast we examined characteristics of these relaxation flows including frontal propagation speed and temperature changes during the warm water arrivals by using multiyear time series of currents and temperatures from four moorings along the 15 m isobath surface current observations from high frequency radars and satellite sea surface temperature images propagation speeds of the warm fronts relative to ambient waters ranged from 0 04 to 0 46 m s 1 as the fronts arrived at the moorings temperature increases ranged from 0 7 c to 4 2 c in ensemble averages over many frontal arrivals alongshore flow speeds increased by 0 1 0 2 m s 1 over the water column during arrivals cross shore flows were onshore near the surface and offshore near the bottom with speeds of 0 02 0 05 m s 1 this cross shore flow structure persisted as temperature increased during arrivals and ceased when temperatures stopped increasing frontal propagation speeds were correlated with temperature increases at the moorings consistent with forcing by baroclinic pressure gradients compared to other buoyant flows such as from the chesapeake bay where density contrasts with ambient waters are 2 3k g m 3 these relaxation flows are less buoyant with density contrasts of 0 1 0 9 kg m 3 consequently the propagation of these flows is more affected by bottom friction and the speeds are closer to the slope controlled or bottom advected limit described in theoretical and laboratory work but not well studied in the ocean

data assimilation model study of wind effects in the santa barbara channel seasonal mean circulation in the santa barbara channel sbc consists of poleward flow on the northern shelf and equatorward flow on the southern shelf while the equatorward flow is in the direction of the persistent upwelling favorable wind the inshore poleward flow is against the wind the channel circulation also has a strong seasonal signal that the cyclonic circulation strengthens considerably in spring and summer a three dimensional model is used to simulate the observed currents over an 8 month period from january to august 1994 the model assimilates the moored temperature and salinity data obtained from a comprehensive circulation study in the sbc santa maria basin smb the model also incorporates surface wind forcing the mesoscale wind stress pattern is derived from a dense network of weather buoys the model simulation reproduces well the surface mean currents and their seasonal monthly variability the transient less than seasonal model velocity response consists of two fundamental modes a wind forced mode and an alongshore pressure gradient forced mode the wind driven circulation is concentrated west of the channel in the smb the alongshore pressure gradient forced motion is concentrated in the channel along the northern coast analysis of the evolution of inshore poleward current suggests that the spring transition in this region may coincide with the end of the winter storm season

hillslope riparian stream connectivity and flow directions at the panola mountain research watershed to obtain a better understanding of water s journey from the hillslope to the stream water level time series from 26 groundwater wells in a hillslope riparian study area in the panola mountain res

physical properties governing groundwater flow in a glacial till catchment abstract hydraulic conductivity surface topography and sediment thickness influence the spatial and temporal pattern of groundwater flow and stream discharge in an unconfined aquifer in a 3 7ha headwater catchment in central ontario canada groundwater levels in the soils adjacent to the stream also significantly influence the magnitude and spatial distribution of stream discharge topographic convergence in plan and decreasing sediment thickness along flowpaths result in surface saturation and groundwater discharge hillslope gradients adjacent to discharge areas determination how fluctuating groundwater levels influence the extent of spatial variations in surface saturation and saturation within the soils as a result of spatial differences in hillslope gradients the spatial patterns of both groundwater and stream discharge change with fluctuating groundwater levels unsaturated sediment s in upslope locations store water infiltrating during wet periods such that groundwater flow from upslope sediments maintains high groundwater levels near the stream and supplies baseflow during dry periods the direction of horizontal groundwater flow in harp 4 21 is not perpendicular to topographic contours so that subcatchment boundaries based on topographic divides differ by as much as 57 from their true subcatchment boundaries based on groundwater divides therefore groundwater flow models based on surface topography may incorrectly predict the spatial pattern of stream discharge

hillslope hydrology and wetland response of two small zero order boreal catchments on the precambrian shield two precambrian shield zero order catchments were monitored from january 2003 to july 2004 to characterize their hydrological and biogeochemical characteristics prior to a forest management experiment hydrometric observations were used to examine temporal trends in hillslope wetland connectivity and the hillslope runoff processes that control wetland event response the hillslope groundwater flux from the longer transect e1 was continuous throughout the study period groundwater fluxes from a shorter and steeper hillslope e0 were intermittent during the study period large depression storage elements termed micro basins located on the upper hillslope of the e1 catchment appeared to be at least partly responsible for the observed rapid wetland runoff responses these micro basins were hydrologically connected to a downslope wetland by a subsurface channel of glacial cobbles that functioned as a macropore channel during episodic runoff events the runoff response from the hilltop micro basins is controlled by antecedent water table position and water is quickly piped to the wetland fringe through the cobble channel during high water table conditions during periods of low water table position seepage along the bedrock soil interface from the hilltop micro basin and other hillslopes maintained hillslope wetland connectivity the micro basins create a dynamic variable source area runoff system where the contributing area expands downslope during episodic runoff events the micro basins occupied 30 of the e1 catchment and are a common feature on the precambrian shield copyright 2007 john wiley sons ltd

low frequency waves in the santa barbara channel observed by high frequency radar are antisymmetric with a mean propagation speed of 5k m d 1 and relative vorticity of order 0 1 f complex empirical orthogonal function decomposition in the 10 20 day passband partitions variance into two dominant modes the first mode represents the vortices with an average period of 14 4 days the second mode represents alongshore fluctuations with an average period of 13 3 days amplitude functions of the two modes correlate with in situ current time series at 5 and 45 m depths obtained from moorings at the east and west channel entrances suggesting coupling with the larger scale circulation of the northern southern california bight the observations support interpretation of mode 2 as a coastal trapped wave since the period and alongshore flow are consistent with previous observations and predictions we hypothesize that mode 1 is a resonant response of the santa barbara basin in the form of a trapped topographic rossby mode the spatial mode resembles the predicted pattern based on a simplified analytical model of the fundamental mode the amplitude of mode 1 is consistently large when the frequencies of modes 1 and 2 converge suggesting that the vortices are a basin scale resonant response to coastal trapped waves index terms 4520 oceanography physical eddies and mesoscale processes 4512 oceanography physical currents 4508 oceanography physical coriolis effects 4516 oceanography physical eastern boundary currents 4544 oceanography physical internal and inertial waves keywords propagating eddies santa barbara channel coastal trapped waves citation beckenbach e and l washburn 2004 low frequency waves in the santa barbara channel observed by high frequency radar j geophys res 109 c02010 doi 10 1029 2003jc001999

altimeter derived surface circulation in the large scale ne pacific gyres part 2 1997 1998 el nino anomalies abstract changes in the sea surface heights ssh and geostrophic transports in the ne pacific are examined during the 1997 1998 el nino using altimeter data sea level pressure slp fields proxy winds and satellite sea surface temperature sst most of the signal occurs along the boundaries of the basin from panama to the alaska peninsula changes in the ssh and alongshore transports along the boundaries are caused both by propagation of signals from the south stronger between the equator and the gulf of california and by local and basin scale winds stronger between the pacific northwest and the alaska peninsula two periods of high ssh occur at the equator may july 1997 and october 1997 january 1998 the first coastal ssh signal moved quickly polewards to approximately 24 n in early june then stalled and moved farther north during transient events in july september large scale wind forcing combined with the equatorial signals during the second period of high equatorial ssh fall 1997 to move the high ssh and poleward transports quickly around the alaska gyre a connection between the boundary currents and the interior north pacific developed as part of the large scale response to the basin scale winds after changes in the boundaries decreases in anomalies of ssh and poleward transports began in january 1998 south of 40 n and in february 1998 farther north

greenland ice sheet mass balance reconstruction part ii surface mass balance 1840 2010 abstractmeteorological station records ice cores and regional climate model output are combined to develop a continuous 171 yr 1840 2010 reconstruction of greenland ice sheet climatic surface mass balance bclim and its subcomponents including near surface air temperature sat since the end of the little ice age independent observations are used to assess and compensate errors melt water production is computed using separate degree day factors for snow and bare ice surfaces a simple meltwater retention scheme yields the time variation of internal accumulation runoff and bare ice area at decadal time scales over the 1840 2010 time span summer june august sat increased by 1 6 c driving a 59 surface meltwater production increase winter warming was 2 0 c substantial interdecadal variability linked with episodic volcanism and atmospheric circulation anomalies is also evident increasing accumulation and melt rates bare ice area and meltwater retention are driven by increasing sat as a con

storm related sedimentation influenced by coastal configuration in the stratigraphic record of a tectonically active shelf upper pleistocene le castella terrace italy abstract analysis of patterns of coastal circulation and sediment dispersal is an essential step for the study of controlling factors influencing the long term dynamics of coastal systems modern settings offer the possibility to monitor relevant parameters over relatively short time spans however geological examples complement this perspective by providing a time averaged record where longer trends and stratigraphically significant processes can be evaluated this study investigates the shallow marine deposits of le castella terrace upper pleistocene southern italy to document how patterns of circulation influenced by coastline configuration can affect the preserved millennial scale depositional record of a progradational shoreline system the regressive portion of the le castella terrace deposits developed during a relative sea level highstand and falling stage consists of a progradational wedge mainly composed of redistributed skeletal particles of a coeval shallow water carbonate factory preservation of the morphology of the paleocoastline and abundant current related sedimentary structures allow reconstruction of the predominant sediment dispersal dynamics responsible for the formation of this sedimentary wedge facies and paleocurrent analysis indicate offshore and alongshore sediment transport modes consistent with coastal circulation driven by storms normally incident to the shoreline and a sharp change in coastline orientation this coastal inflection influenced circulation patterns causing flow separation and eddy formation in the lee of the curved coastline syndepositional tectonic deformation also affected the architecture of the preserved deposits controlling the nucleation and development of a clinostratified body and determining localized lateral stratigraphic variability this study illustrates how transient but recurrent circulation patterns associated with changes in coastal orientation and related to high energy storm events can leave a predominant signature in the stratigraphic record of microtidal shallow marine successions

an enhanced temperature index glacier melt model including the shortwave radiation balance development and testing for haut glacier d arolla switzerland an enhanced temperature index glacier melt model incorporating incoming shortwave radiation and albedo is presented the model is an attempt to combine the high temporal resolution and accuracy of physically based melt models with the lower data requirements and computational simplicity of empirical melt models represented by the degree day method and its variants the model is run with both measured and modelled radiation data to test its applicability to glaciers with differing data availability five automatic weather stations were established on haut glacier d arolla switzerland between may and september 2001 reference surface melt rates were calculated using a physically based energy balance melt model the performance of the enhanced temperature index model was tested at each of the four validation stations by comparing predicted hourly melt rates with reference melt rates predictions made with three other temperature index models were evaluated in the same way for comparison the enhanced temperature index model offers significant improvements over the other temperature index models and accounts for 90 95 of the variation in the reference melt rate the improvement is lower but still significant when the model is forced by modelled shortwave radiation data thus offering a better alternative to existing models that require only temperature data input

data assimilation model study of the santa barbara channel circulation the seasonal circulation in the santa barbara channel sbc consists of a cyclonic eddy in the western basin and a poleward current along the northern coast in this study the monthly mean circulation is simulated using a three dimensional primitive equation model with data assimilation included the data are derived from the santa barbara channel and santa maria basin coastal circulation study covering an 8 month period from january to august 1994 the 6 hourly moored temperature observations in the upper 100 m water column are continuously assimilated into the model using a local correction method although salinity and wind forcing are not explicitly included comparisons with the observations indicate that the model results generate realistic flow and temperature structures inside the sbc the assimilation model faithfully reproduces the cyclonic eddy but it fails to predict the currents at the exits of the channel the issue of the data need is addressed through a sensitivity study

subtidal inner shelf circulation near point conception california 1 we discuss connections between inner shelf and mid shelf circulation near point conception california as well as the wind forcing of inner shelf circulation point conception marks the southern edge of a major upwelling zone that extends from oregon to central california the coastline makes a sharp eastward turn at point conception and the santa barbara channel to the east is generally assumed to be an upwelling shadow consistent with this regional division inner shelf currents are strongly correlated with wind north of point conception but not in the santa barbara channel one exception to this generalization is a location in the santa barbara channel near a pass that cuts through the coastal mountains where local winds have a dominant cross shore component and directly drive cross shore currents over the inner shelf inner shelf currents in the santa barbara channel when compared with mid shelf currents in that area are weaker but strongly correlated by contrast inner shelf currents north of point conception show a far greater incidence of poleward flow than is seen over the mid shelf in that area poleward flow events lasting 1 5 days transport warm water from the santa barbara channel around point conception to the central california coast these events are associated with relaxation of the generally equatorward wind but not always with mid shelf flow reversals

on enso coastal currents and sea levels abstract sea level measurements along the western coast of the americas have shown that there is a strong signal at enso frequencies approximately 2 2 yr 1 to 2 5 yr 1 that propagates poleward at about 40 to 90 cm s 1 this enso sea level signal must be associated with enso coastal currents but because adequate interannual current time series are unavailable the structure and strength of these currents are not known coastal enso currents must be fundamentally affected by bottom topography and bottom friction but previous theory has not taken these effects into account a near boundary numerical model with realistic bottom friction stratification and shelf and slope topography was therefore constructed to study enso coastal flow i at enso frequencies previous results for models with no bottom topography and no bottom friction suggest that sea level should not propagate poleward with realistic bottom friction and bottom topography coastal sea level propagates poleward at speeds similar to tho

distant effect of assimilation of moored currents into a model of coastal wind driven circulation off oregon 1 an optimal interpolation oi sequential algorithm is implemented for a threedimensional primitive equation model to assimilate current measurements from acoustic doppler profilers moored on the oregon shelf as a part of the coastal ocean advances in shelf transport coast upwelling experiment may august 2001 a stationary estimate of the forecast error covariance required by the oi is computed based on the error covariance in the model solution not constrained by data assimilation lagged model error covariances are used to account for the effect of previously assimilated data the forecast error covariance has a shorter alongshore spatial scale than the model error covariance unconstrained by the data as an effect of propagating dynamical modes assimilation of currents from one or two of the moorings located on the path of the upwelling jet helps to improve the model data rms error and correlation at the mooring sites located at an alongshore distance of 90 km south or north from the assimilation sites the coastal jet is deflected offshore over heceta bank and assimilation of data from an inner shelf mooring in the jet separation zone does not help to improve prediction in the far field larger improvements are obtained for the first part of the study period yeardays 146 190 in the second part days 191 237 the geometry of our limited area model possibly limits prediction accuracy in numerical experiments involving assimilation of data from only one mooring the actual and expected rms error improvements are compared providing a consistency test for the forecast error covariance

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

a separating coastal upwelling jet at cape blanco oregon and its connection to the california current system the coastal upwelling region near cape blanco oregon 433n o the west coast of the united states was studied using a towed ctd on seasoar a shipboard acoustic doppler current pro ler adcp satellite sea surface temperature maps and surface drifters during august 1995 the equatorward upwelling jet was inshore of the shelfbreak north of cape blanco meandered gently o shore around the cape and then veered sharply o shore just to the south of the cape analysis of vertical sections of density velocity and spicinessa con rmed the separation of an upwelling jet and front the jet was followed from over the shelfbreak north of the cape to 100 km o shore downstream of the cape the separating jet originates from the coastal upwelling jet leaving the shelf but is augmented by an o shore branching of the poleward undercurrent by combining information from adcp streamfunction maps with analysis of hydrographic data including distributions of the tracer like quantity spicinessa a conceptual model of the three dimensional circulation near the cape emerges a mid shelf upwelling jet encounters a coastal promontory then turns o shore stretching and deepening as it crosses the continental margin the jet then turns back shoreward cyclonically where the deepened equatorward ow encounters the top of the poleward undercurrent owing along the continental slope this causes a portion of the undercurrent to turn o shore to join and strengthen the equatorward transport in the separated jet throughout the separation process the coastal upwelling front and jet are continuous robust features separation of a coastal upwelling jet is an important mechanism for cross shelf transport from the coast to the deep ocean cape blanco appears to be the northernmost point where an equatorward jet regularly separates from the coast to become an oceanic jet and thus serves as the northern boundary of the region where an intense meandering current characteristic of the california current system