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

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

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

northern monterey bay upwelling shadow front observations of a coastally and surface trapped buoyant plume 1 during the upwelling season in central california northwesterly winds along the coast produce a strong upwelling jet that originates at point ano nuevo and flows southward across the mouth of monterey bay a convergent front with a mean temperature change of 3 77 0 29c develops between the warm interior waters and the cold offshore upwelling jet to examine the forcing mechanisms driving the location and movement of the upwelling shadow front and its effects on biological communities in northern monterey bay oceanographic conditions were monitored using cross shelf mooring arrays drifters and hydrographic surveys along a 20 km stretch of coast extending northwestward from santa cruz california during the upwelling season of 2007 may september the alongshore location of the upwelling shadow front at the northern edge of the bay was driven by regional wind forcing through an alongshore pressure gradient buoyancy forces due to the temperature change across the front and local wind forcing the diurnal sea breeze the upwelling shadow front behaved as a surface trapped buoyant current which is superimposed on a poleward barotropic current moving up and down the coast up to several kilometers each day we surmise that the front is advected poleward by a preexisting northward barotropic current of 0 10 m s 1 that arises due to an alongshore pressure gradient caused by focused upwelling at point ano nuevo the frontal circulation onshore surface currents breaks the typical two dimensional wind driven cross shelf circulation offshore surface currents and introduces another way for water and the material it contains e g pollutants larvae to go across the shelf toward shore

statistics of internal tide bores and internal solitary waves observed on the inner continental shelf off point sal california abstractmoored observations of temperature and current were collected on the inner continental shelf off point sal california between 9 june and 8 august 2015 the measurements consist of 10 moorings in total 4 moorings each on the 50 and 30 m isobaths covering a 10 km along shelf distance and an across shelf section of moorings on the 50 40 30 and 20 m isobaths covering a 5 km distance energetic highly variable and strongly dissipating transient wave events termed internal tide bores and internal solitary waves isws dominate the records simple models of the bore and isw space time behavior are implemented as a temperature match filter to detect events and estimate wave packet parameters as a function of time and mooring position wave derived quantities include 1 group speed and direction 2 time of arrival time duration vertical displacement amplitude and waves per day and 3 energy density energy flux and propagation loss in total over 1000 bore events and over 9000 isw events

the influence of diurnal winds on phytoplankton dynamics in a coastal upwelling system off southwestern africa abstract at a coastal upwelling zone near 30 s latitude diurnal wind variability forced energetic inertial current oscillations 0 5 m s 1 that materially influenced phytoplankton distribution and productivity the diurnal inertial band resonance found at this latitude in the benguela upwelling system allowed rapid efficient transfer of energy from counterclockwise rotating winds into anticyclonic currents upon the onset of the transition from relaxation to upwelling conditions these inertial band oscillations caused regular pycnocline outcropping at the surface and the vertical advection of nutrient rich waters in the coastal zone vertical pycnocline outcropping was coincident with the vertical redistribution of chlorophyll a fluorescence from a subsurface maximum to entrainment into the surface mixed layer in effect turning vertical phytoplankton gradients into horizontal ones the shear caused by the vertical structure of the inertial oscillations during and after the onset of wind forcing was intense enough to erode the strong stratification established during a prior relaxation period according to richardson number and strain analyses this diapycnal mixing also had the consequence of mixing heat and chlorophyll downwards and nutrient rich water upwards such that the surface nitrate concentration became non zero chlorophyll concentrations thereafter increased in what qualitatively appeared to be a phytoplankton bloom this diurnal inertial resonance driven mechanism for mixing driven nutrient flux embedded within the low frequency advective vertical flux forced by ekman dynamics enhanced the efficiency of wind forcing to produce high phytoplankton productivity and is likely to be of first order importance in bloom dynamics in the study area including harmful algal blooms our results argue that in general high frequency physical dynamics should be considered when studying the bottom up forcing of algal blooms and red tide events

changing depths of magma fractionation and stagnation during the evolution of an oceanic island volcano la palma canary islands la palma canary islands represents an oceanic island volcano with an active rift zone inferred to have formed during the last 800 ka following southward growth of the former radial symmetrical stratovolcano taburiente we carried out clinopyroxene melt thermobarometry and microthermometry of fluid inclusions to reconstruct the evolution of the magma plumbing systems over time and to understand the genetic relationship between taburiente and the presently active cumbre vieja rift zone clinopyroxene melt equilibria of phenocryst rims and glassy groundmass indicate pressures of 0 60 1 04 gpa 19 34 km depth for taburiente 0 47 1 17 gpa 16 40 km for the former cumbre nueva rift arm of taburiente and 0 50 0 78 gpa 16 26 km for bejenado volcano that formed after collapse of the cumbre nueva rift these pressures are interpreted to reflect depths of magma storage and major crystal fractionation co2 dominated fluid inclusions hosted by clinopyroxenes and olivines indicate pressures of formation or re equilibration within an overall range of 0 25 0 61 gpa 8 19 km depth respective frequency maxima are at 0 41 0 50 gpa for taburiente dunite xenoliths 0 26 0 43 gpa for cumbre nueva ankaramites and 0 26 0 32 gpa for bejenado cumulate xenoliths these pressures are interpreted to reflect levels of temporary magma stagnation during ascent our data show that the magma pathways during all volcanic phases including the presently active cumbre vieja rift klugel a hansteen t h galipp k 2005 magma storage and underplating beneath cumbre vieja volcano la palma canary islands earth and planetary science letters 236 211 226 are characterized by two distinct storage levels a system of prolonged storage within the upper mantle and a system of short term stagnation within the lower crust or near to the moho both the mantle and crustal storage systems show a migration to shallower levels from 1 0 ma to present probably as a result of changing thermomechanical properties of the mantle and crust and possibly stoping our combined barometric data and field observations suggest that the extinct taburiente cumbre nueva and the active cumbre vieja represent two distinct volcanoes with separate magma plumbing systems in this case the present rift configuration does not reflect continuous growth of the taburiente shield volcano during the last 800 ka none of the la palma volcanoes shows any indicators of a long lived shallow magma reservoir where magmas fractionate and from which rift zones emanate which is an important difference to hawaiian shield volcanoes characterized by shallow subcaldera magma chambers

seasonal differences in the current and temperature variability over the northern california shelf during the coastal ocean dynamics experiment a long term moored array was maintained over the northern california continental shelf from april 1981 to april 1983 as part of the coastal ocean dynamics experiment to determine the seasonal differences in the current and water temperature characteristics the array consisted of two midshelf moorings and one upper slope mooring from april 1981 through july 1982 and one midshelf mooring from august 1982 to april 1983 the two summers were characterized by southeastward mean wind stresses upwelling favorable cold water isotherms sloping upward toward the coast and a sheared equatorward mean shelf current the intervening fall and winter were characterized by a weak mean wind stress relatively warm shelf water level isotherms and a more barotropic poleward mean shelf current in contrast to the differences in the characteristics of the means many of the characteristics of the current and temperature variability are the same for the summer and winter the vertical structure of the largest current empirical orthogonal functions eofs for each of the shelf moorings which account for more than 75 of the subtidal variance do not vary with season the current is vertically sheared oriented 15 20 clockwise relative to local isobaths near the surface and along isobaths near the bottom currents at the two shelf moorings alongshore separation 29 37 km are correlated with each other and with the local wind stress and these relationships do not exhibit a seasonal variation denser arrays of wind and current sensors during the two summers indicated that there were strong persistent variations in the wind field over relatively small scales tens of kilometers with corresponding variations in the shelf current field during the summer of 1981 but not during the summer of 1982 over the slope the largest eofs account for 56 72 of the current variance and have a vertical structure which is relatively uniform with depth during the summer fall and winter of 1981 but is strongly sheared in the upper 100 m during the summer of 1982 current observations over the slope are not correlated with either the shelf currents or the local wind stress during any season in contrast the temperature variability as described by eofs does exhibit a seasonal variation in vertical structure with the variability concentrated in the upper 20 30 m in summer and more uniform with depth in winter the near surface temperature variability over the slope is correlated with the shelf temperature variability estimates of the cross shelf heat flux due to the wind driven ekman transport accounts for a large part of the shelf temperature variability observations from the midshelf mooring maintained through the fall and winter of 1982 1983 showed evidence of the 1982 1983 el nino with persistent onshore and poleward currents and water temperatures typically above 12 c

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

buoyant gravity currents along a sloping bottom in a rotating fluid author posting cambridge university press 2002 this article is posted here by permission of cambridge university press for personal use not for redistribution the definitive version was published in journal of fluid mechanics 464 2002 251 278 doi 10 1017 s0022112002008868

deep intrusions lateral magma transport and related uplift at ocean island volcanoes abstract oceanic intraplate volcanoes grow by accumulation of erupted material as well as by coeval or discrete magmatic intrusions dykes and other intrusive bodies within volcanic edifices are comparatively well studied but intrusive processes deep beneath the volcanoes remain elusive although there is geological evidence for deep magmatic intrusions contributing to volcano growth through uplift this has rarely been demonstrated by real time monitoring here we use geophysical and petrological data from el hierro canary islands to show that intrusions from the mantle and subhorizontal transport of magma within the oceanic crust result in rapid endogenous island growth seismicity and ground deformation associated with a submarine eruption in 2011 2012 reveal deep subhorizontal intrusive sheets sills which have caused island scale uplift of tens of centimetres the pre eruptive intrusions migrated 15 20 km laterally within the lower oceanic crust opening pathways that were subsequently used by the erupted magmas to ascend from the mantle to the surface during six post eruptive episodes between 2012 and 2014 further sill intrusions into the lower crust and upper mantle have caused magma to migrate up to 20 km laterally resulting in magma accumulation exceeding that of the pre eruptive phase a comparison of geobarometric data for the 2011 2012 el hierro eruption with data for other atlantic intraplate volcanoes shows similar bimodal pressure distributions suggesting that eruptive phases are commonly accompanied by deep intrusions of sills and lateral magma transport these processes add significant material to the oceanic crust cause uplift and are thus fundamentally important for the growth and evolution of volcanic islands we suggest that the development of such a magma accumulation zone in the lower oceanic crust begins early during volcano evolution and is a consequence of increasing size and complexity of the mantle reservoir system and potentially the lithospheric stresses imposed by increasing edifice load

poleward propagating subinertial alongshore surface currents off the u s west coast 1 the network comprising 61 high frequency radar systems along the u s west coast uswc provides a unique high resolution and broad scale view of ocean surface circulation subinertial alongshore surface currents show poleward propagating signals with phase speeds of o 10 and o 100 300 km d 1 that are consistent with historical in situ observations off the uswc and that can be possibly interpreted as coastally trapped waves ctws the propagating signals in the slow mode are partly observed in southern california which may result from scattering and reflection of higher mode ctws due to curvature of shoreline and bathymetry near point conception california on the other hand considering the order of the phase speed in the slow mode the poleward propagating signals may be attributed to alongshore advection or pressure driven flows a statistical regression of coastal winds at national data buoy center buoys on the observed surface currents partitions locally and remotely wind forced components isolates footprints of the equatorward propagating storm events in winter off the uswc and shows the poleward propagating signals year round

sub mesoscale coastal eddies observed by high frequency radar a new mechanism for delivering nutrients to kelp forests in the southern california bight 1 sub mesoscale eddies are described along the mainland coast of the santa barbara channel based on observations from a network of high frequency hf current measuring radars and near shore moorings the eddies are 4 15 km in diameter and typically last about 2 days although some last up to 6 days most eddies within the radar coverage area are anti cyclonic with relative vorticities of 0 4 f to 0 8 f where f is the coriolis parameter but cyclonic eddies are also observed moored observations over the inner shelf 12 m water depth of a sequence of two eddies in december 2001 show an increase in nitrate plus nitrite from the background levels of 1 2 m to a maximum of 10 12 m when the eddies are present we speculate that these eddies are an important transport mechanism for nutrients and biogenic particles to inner shelf ecosystems of the southern california bight

density changes of fluid inclusions in high pressure low temperature metamorphic rocks from crete a thermobarometric approach based on the creep strength of the host minerals abstract the densities of fluid inclusions in quartz from high pressure low temperature metamorphic rocks are generally inconsistent with the p t conditions derived from solid phase equilibria therefore some process of change must regularly have occurred during exhumation however evidence of decrepitation is frequently lacking consideration of the rates of change of p and t in metamorphic rocks shows that very low strain rates are sufficient for volume adaptation dislocation creep appears to be a feasible deformation mechanism allowing for continuous ballooning driven by a small differential pressure during decompression down to temperatures of about 300 c in quartz decrepitation requires a higher differential pressure in natural rocks it is therefore restricted to relatively low temperatures this concept was tested on inclusions in the phyllite quartzite unit of crete in these rocks cooling to below ca 300 c at confining pressures of 3 to 4 kbar is indicated corresponding to depths of 10 to 13 km it is anticipated that in metamorphic rocks the isochores of all fluid inclusions in quartz that have been formed at higher temperatures and remain unaffected by decrepitation should intersect close to the 300 c isotherm thereby defining a point on the p t paths rarely accessible by other methods extension of this concept to other minerals with known mechanical properties is straightforward and can under favourable circumstances be used to fix several points on p t paths

internal wave attenuation by coastal kelp stands abstract coastal kelp stands are a unique physical environment having high drag distributed throughout the water column temperature records from locations at increasing distances into the kelp show a damping of high frequency variance and a slowing of wave propagation at low frequencies this behavior at low frequencies is more a diffusion than a wave process linearized internal wave models incorporating linear drag successfully explain the frequency response of phase velocity but are less successful with the attenuation coefficient the attenuation coefficient is well explained by the model of the outer area of the kelp but is overestimated in the kelp stand interior in the outer area phase velocity is about 0 12 m s 1 at 100 cpd cycles per day a third of that at 1 cpd attenuation coefficient is 7 5 km 1 at 100 cpd 1 5 km 1 at 1 cpd

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

experimental stretching of fluid inclusions in calcite implications for diagenetic studies homogenization temperatures of fluid inclusions trapped in calcite crystals may change with increased heating beyond the homogenization temperature fluid inclusions trapped in calcite during basin subsidence will tend to yield homogenization temperatures approaching maximum burial temperatures diagenetic studies that depend on these data will be biased coarse crystalline calcite containing saline fluid inclusions was used to examine the influence of increased temperatures and pressures on measured homogenization temperatures stepped heating experiments were conducted at 1 atm over a temperature range of 90 to 245 c along with hydrothermal experiments at confining pressures of 173 and 691 bar and temperatures of 160 250 and 350 c in all cases significant increases in the homogenization temperatures of the inclusion population were recorded presumably stresses generated during heating of the fluid inclusions exceeded the combined strength of the calcite crystal and the external pore pressure and thus caused fluid inclusion stretching size is a secondary factor that controls fluid inclusion reequilibration

poleward along shore current pulses on the inner shelf of the bay of biscay abstract we analyzed strong events of coastal poleward along shore currents above 10 cm s 1 and up to more than 50 cm s 1 on the inner shelf 50 80 m depth of the bay of biscay bob from the spanish coast to the brittany coast we used data from four acoustic doppler current profilers adcps deployed from july 2009 to august 2011 the goal of this study was to analyze current variability at meso and subinertial scales and its generation mechanism these currents occurred all year long and were classified into three types events occurring principally in the southern part of the bob were classified as southern events bay scale events were defined when strong poleward currents were detected over all the shelf typically stronger on the spanish and the southern brittany shelves strong events were characterized by depth averaged current velocities over 40 cm s 1 in the southern part of the bob at short time lags the along shore currents were clearly related to along shore wind stress at upstream locations an explanation is provided for longer time lags in terms of coastal trapped wave ctw dynamics the first ctw mode phase speeds were in agreement with the propagation speeds of the fastest events 5 m s 1 while inner shelf modes could explain the slowest events 1 3 m s 1 the cross shelf density gradient and the extension of the ipc were also associated with strong coastal poleward along shore currents the duration of the events the vertical structure of the currents and the associated coastal trapped waves were studied in relation with the stratification

local diurnal wind driven variability and upwelling in a small coastal embayment the oceanic response to high frequency local diurnal wind forcing is examined in a small coastal embayment located along an understudied stretch of the central california coast we show that local diurnal wind forcing is the dominant control on nearshore temperature variability and circulation patterns a complex empirical orthogonal function ceof analysis of velocities in san luis obispo bay reveals that the first mode ceof amplitude time series which accounts for 47 9 of the variance is significantly coherent with the local wind signal at the diurnal frequency and aligns with periods of weak and strong wind forcing the diurnal evolution of the hydrographic structure and circulation in the bay is examined using both individual events and composite day averages during the late afternoon the local wind strengthens and results in a sheared flow with near surface warm waters directed out of the bay and a compensating flow of colder waters into the bay over the bottom portion of the water column this cold water intrusion into the bay causes isotherms to shoal toward the surface and delivers subthermocline waters to shallow reaches of the bay representing a mechanism for small scale upwelling when the local winds relax the warm water mass advects back into the bay in the form of a buoyant plume front local diurnal winds are expected to play an important role in nearshore dynamics and local upwelling in other small coastal embayments with important implications for various biological and ecological processes

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

micromechanical modeling of healed crack orientations as a paleostress indicator application to precambrian granite from illinois and wisconsin we have used a micromechanical four grain model to simulate intragranular cracks produced during primary cooling of a granitic pluton in a horizontally anisotropic stress field the orientations of vertical intragranular cracks were obtained using the criterion that they are perpendicular to the maximum principal tensile stress when it exceeds the local tensile strength the preferred orientation was always parallel to the maximum regional compressive stress direction the sharpness of the distribution peak increases with the ratio of the maximum to minimum horizontal stress we applied the model results to new and previous data on precambrian granites from wisconsin and illinois our new data are healed crack orientations and fluid inclusion properties in unoriented granite core from illinois borehole uph 2 the fluid inclusion measurements and isotopic age dates indicate that most healed cracks were formed during the primary cooling of the pluton the fluid inclusion characteristics and shape of the crack orientation distribution were almost identical to those previously determined for uph 3 1 km away kowallis et al 1987 suggesting that the preferred orientation of healed cracks in granite from uph 2 is the same as for uph 3 n25 w 5 the orientation distribution from the micromechanical model for a stress ratio of 4 is very similar to the healed crack orientation distribution measured in several precambrian granites from the midcontinent region we conclude that healed crack orientations are useful indicators of the paleostress field and that they may be used as a tool for orienting core in stable structurally simple regions

characterizing storm water dispersion and dilution from small coastal streams characterizing the dispersion and dilution of storm water from small coastal creeks is important for understanding the importance of land derived subsidies to nearby ecosystems and the management of anthropogenic pollutants in southern california creek runoff is episodic intense and short lived while the plumes are buoyant all of which make the field sampling of freshwater plumes challenging numerical modeling offers a viable way to characterize these systems the dilution and dispersion of freshwater from two creeks that discharge into the santa barbara channel california is investigated using regional ocean modeling system roms simulations with a horizontal resolution of 100 m tight coupling is found among precipitation hydrologic discharge wind forcing and submesoscale flow structures which all contribute to plume evolution during flooding plumes are narrow and attached to the coast due to downwelling onshore wind forcing and intense vorticity filaments lying parallel to the shelf as the storm passes the winds typically shift to offshore upwelling favorable conditions and the plume is advected offshore which enhances its dilution plumes reach the bottom nearshore while they form thin layers a few meters thick offshore dilution field of passive tracers released with the runoff is strongly anisotropic with stronger cross shelf gradients than along shelf dispersion analysis of statistical moments of the passive tracer distribution results in scale dependent diffusivities consistent with the particle pair analysis of romero et al 2013 model validation the roles of submesoscale processes and wind forcing on plume evolution and application to ecological issues and marine resource management are discussed

rheology of the plate interface dissolution precipitation creep in high pressure metamorphic rocks abstract subduction zone models invoke deformation to be concentrated along the plate interface in a region of particularly low temperature geophysical observations do not provide constraints on temperature stress and deformation patterns with desired resolution in contrast the record of high pressure metamorphic rocks exhumed from subduction zones provides details on p t history deformation mechanisms and stress state albeit not readily correlated with the former dynamic situation on larger scale here we review available information on dissolution precipitation creep dpc in high pressure metamorphic rocks which if representative for subduction zones in general can pose constraints on conditions rheology and flow patterns along the plate interface the key observations and conclusions are that 1 deformation is typically highly inhomogeneous and localized into shear zones 2 stresses are generally too low to drive crystal plastic deformation 3 microfabrics suggest dissolution precipitation creep to be the predominant deformation mechanism 4 an aqueous fluid at quasi lithostatic pressure is available throughout allowing for tensile fracturing and crack healing or sealing 5 low stress combined with high strain rates required for localized deformation at typical subduction rates implies low viscosity and 6 contribution of shear heating to the thermal budget of subduction zones should be moderate the dominant deformation mechanism dpc is reviewed in some detail including experimental and theoretical approaches various examples of dpc in high pressure metamorphic rocks are illustrated emphasizing the role of interphase boundaries as sites of dissolution rheology governed by dpc is proposed to control interplate coupling and development of a subduction channel with return flow being a likely candidate for rapid exhumation of high pressure metamorphic rocks

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

relaxation from upwelling in the coastal ocean dynamics experiment a relaxation of the upwelling system on the northern california shelf occurs when upwelling favorable winds decay or reverse observations from the coastal ocean dynamics experiment are used to investigate this process with emphasis on the near surface temperature evolution models of relaxation warming are tested for the surface layer 0 30 m over midshelf with the result that the surface heat flux and poleward alongshelf advection can account for the observed temperature behavior onshore advection of the upwelled isopycnal field is a relatively unimportant contribution the warming patterns that are observed and which provide the gradients for the advective process have wedgelike shapes warmest inshore and in the south of the experimental area these patterns appear to be related to a topographic influence of point reyes possibly through the generation of gradients in the wind field remote advection of warm water from as far south as san francisco occasionally occurs as well the nature of the relaxation mechanism has general implications a new warm saline nutrient rich water mass may be formed in the surface layer since the warming processes are not the reverse of the cooling an important asymmetry is present it causes time variable upwelling to generate conditions very different from steady upwelling a new upwelling front is created during each event with upwelled water seaward of it and reversed alongshelf flow contributes to the warming and exchange mechanisms the system cannot be described or understood without the irreversible processes during upwelling and relaxation or without a mixed layer

water mass circulation on the continental shelf of the gulf of cadiz acoustic doppler current profiler data collected during three successive surveys in the gulf of cadiz in may june 2001 have been used to analyse the surface circulation on the continental shelves of the gulf of cadiz and how this circulation matches the circulation in the ocean side of the gulf the wider and larger eastern continental shelf holds a cyclonic circulation bounded at the south by a shelf break jet that is identified with the huelva front the coastal current that closes the gyre at the north is identified with the warm counterflow mentioned in the literature under westerly winds this counter current recirculates toward the east while recent upwelled water near cape santa maria is advected downstream by the shelf break jet leaving the cold signature at the surface that has been identified historically with the huelva front under easterlies part of the coastal counterflow invades the western continental shelf while the remaining recirculates eastward to close the cyclonic cell the western continental shelf and slope is occupied by a larger scale cyclonic eddy that extends into the deep ocean this eddy has vertical length scale of hundreds of metres and is linked to the general wind forcing in the area both cyclonic structures are bounded at the south by a jet that enters in the gulf of cadiz moving around the second eddy and eastward to feed the atlantic inflow through the strait of gibraltar r 2006 elsevier ltd all rights reserved

a modeling study of shelf circulation off northern california in the region of the coastal ocean dynamics experiment response to relaxation of upwelling winds 1 a two part modeling study of the wind forced flow on the continental shelf off northern california in the region 37 40 n of the coastal ocean dynamics experiment code is pursued this paper involves a process oriented study with idealized wind stress forcing gan and allen 2002 involves forcing with observed winds and heat flux for april may 1982 and comparison of model results with code observations a characteristic but previously unexplained response observed during code following the weakening or relaxation of southward upwelling favorable winds is the time dependent development of northward currents over the inner shelf next to the coast the presence of northward winds is not necessary for this occurrence the objective in this paper is to investigate the dynamics of the shelf flow response to upwelling wind relaxation events under idealized conditions in the basic case experiment a spatially uniform upwelling favorable southward wind stress of 0 1 pa is applied to the ocean initially at rest the stress is held constant for 10 days and then decreased linearly to zero over 3 days in response to the southward wind stress southward alongshore currents develop on the shelf accompanied by upwelling of cold dense water near the coast considerable spatial variability in the shelf flow clearly related to the alongshore variations in coastline and bottom topography is found the alongshore currents tend to separate from the coast south of capes and the coldest surface water is found at those locations as the winds decrease northward currents similar to those observed develop on the inner shelf next to the coast at many alongshore locations examination of the alongshore momentum balances shows that the northward currents are forced by a northward pressure gradient force associated with negative alongshore pressure gradients these pressure gradients are set up by the interaction of the wind forced flow with the alongshore variations in shelf topography in general negative alongshore pressure gradients intensified off pt reyes and pt arena by the gradient wind balance are found south of capes the negative pressure gradients geostrophically balance onshore flow at depth and upwelling is strengthened in these locations north of capes positive pressure gradients that are primarily in balance with nonlinear advective effects are found after the winds cease the forced across shelf circulation weakens and the resulting unbalanced negative pressure gradients south of the capes accelerate the alongshore currents northward processes with similar dynamics are found embedded in the more complex coastal ocean response to observed time varying winds by gan and allen 2002

deformation by solution deposition and re equilibration of fluid inclusions in crystals depending on temperature internal pressure and stress abstract changes of shape and density of fluid inclusions in crystals were demonstrated when these crystals were subjected to temperatures and internal pressures greater than those of their growth experimental relations have been established between the rate of length change of the inclusions and the different parameters of the experiment nature of the crystal temperature and internal pressure state of stress on the crystal geometric characters of the inclusion length width orientation of the inclusion with respect to the optical axes of host mineral it is essentially the effect of the variation of surface energy with the curvature around the cavity which causes a mass transfer of the host crystal by diffusion through the fluid under pressure the rate of length change is limited by the rate of dissolution at the median part of elongate inclusions this change of shape and density is known to occur in naturally deformed crystals an example of such a behaviour is given which allowed us to use the inclusions as markers of the conditions of temperature and pressure subsequent to the growth of crystal

the influence of wind forcing on the chesapeake bay buoyant coastal current observations of the buoyant coastal current that flows southward from chesapeake bay are used to describe how the thickness width and propagation speed vary in response to changes in the along shelf wind stress three basic regimes were observed depending on the strength of the wind for weak wind stresses from 0 02 to 0 02 pa the buoyant coastal current was relatively thin the front slope was not steep and the width was variable 1 20 km for moderate downwelling southward wind stresses 0 02 0 07 pa wind driven cross shelf advection steepened the front causing the plume to narrow and thicken for stronger downwelling wind stresses greater than 0 07 pa vertical mixing dominated bulk richardson numbers were approximately 0 25 isopycnals were nearly vertical and the plume front widened but the plume width did not change plume thickness and width were normalized by the theoretical plume scales in the absence of wind forcing normalized plume thickness increased linearly from 1 to 2 as downwelling wind stresses increased from 0 to 0 2 pa normalized plume widths were approximately 1 for downwelling wind stresses from 0 02 to 0 2 pa the observed along shelf propagation speed of the plume was roughly equal to the sum of the theoretical propagation speed and the wind driven along shelf flow

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

internal tide pools prolong kelp forest hypoxic events this study uses field observations within a single kelp bed in southern monterey bay california to evaluate the retention of cold hypoxic water within depressions in the rocky reef following relaxation of internal wave events just as tide pools in the rocky intertidal zone persist in depressions following the relaxation of surface waves and tides internal tide pools persist in depressions in the subtidal reef following the relaxation of internal waves when internal waves contain low dissolved oxygen do water the duration of hypoxic events can be extended for organisms within the pooling zone additionally we suggest that internal wave run up can cause the early arrival of cold hypoxic water in these same areas thereby extending hypoxic events further together internal tide pools and wave run up extend event durations by 20 on average however some events are extended up to 160 of the regional scale event length which may be more ecologically relevant than the mean extension when internal waves contain other environmental covariates e g low ph nutrients internal tide pools are expected to create a similar time extension and patchy landscape in these quantities we attribute the slowing of the relaxation of sub thermocline water within pooling zones to retention within the reef itself rather than a drag effect of the kelp bed following hypoxic internal bores internal tide pools cause a period of extreme spatial variability in the do and temperature field which is likely to impact the distribution and behavior of local organisms

a simple theory for the fate of buoyant coastal discharges abstract a simple theory that predicts the vertical structure and offshore spreading of a localized buoyant inflow onto a continental shelf is formulated the theory is based on two competing mechanisms that move the buoyant fluid offshore 1 the radial spread of the lighter water over the ambient water being deflected by the coriolis force and producing an anticyclonic cyclostrophic plume and 2 offshore transport of buoyant water in the frictional bottom boundary layer that moves the entire plume offshore while maintaining contact with the bottom the surface expression of the cyclostrophic plume moves offshore a distance ys 2 3g h0 2i 2g h0 2i 1 2f where g is reduced gravity based on the inflow density anomaly h0 is the inflow depth i is the inflow velocity and f is the coriolis parameter the plume remains attached to the bottom to a depth given by hb 2l ih0f g 1 2 where l is the inflow width both scales are based solely on parameters of the buoyant inflow at its source there

large scale structure in wind forcing over the california current system in summer abstractthe wind that drives oceanic eastern boundary upwelling systems is highly variable in many locations the standard deviation of wind velocity on time scales of days to weeks is larger than the mean in the 1600 km long california current system ccs the spatial decorrelation scale of the wind fluctuations is 400 800 km suggesting wind fluctuations in the north and south ends of the system are not related yet there is also the suggestion in the literature of a larger scale structure in the fluctuations here empirical orthogonal function eof analysis of buoy and satellite wind velocities confirms the existence of that structure this analysis covers a larger spatial domain than previous eof studies in the ccs and to allow for propagation of the wind fluctuations includes an approach for calculating hilbert eofs from time series with gaps the large scale structure in the wind fluctuations is a quasi dipole pattern spanning the coastline from washington through california it accounts f

mechanical re equilibration of fluid inclusions in san carlos olivine by power law creep fluid inclusions in san carlos olivine stretch via plastic mechanisms when heat treated at 1400 c and 0 1 mpa in controlled f o 2 atmospheres for several days measurable changes in both inclusion dimensions and fluid densities occur densities decrease from 1 0 to 0 7 g cc stretching is fastest along 100 and slower along 001 and 010 the dislocation microstructure around the inclusions suggests that creep mechanisms operate uncertainties in the experimental determinations of stretching rates result from optical resolution limits errors inherent in measuring homogenization temperatures uncertainties in the fluid equation of state and changes in fluid chemistry during the heat treatment inclusion stretching by dislocation creep can be treated using a model developed for hot isostatic pressing in this model we assume spherical symmetry of plastic flow that the material yields by steady state power law creep and that the parameters for the constitutive law and fluid equation of state are known stretching rates are predicted to depend on the difference between the fluid pressure and the external pressure the temperature the constitutive law governing power law creep and geometry predicted stretching rates show fair but not exact agreement with experimentally measured rates the amount of stretching predicted by the model is in rough agreement with estimates based on dislocation microstructures around natural inclusions if xenolith ascent rates are of the order of 1 cm s or faster

the structure and variability of the marine atmosphere around the santa barbara channel the santa barbara channel is a region characterized by coupled interaction between the lower level atmosphere the underlying ocean and the elevated topography of the coastline the nature of these interactions and the resulting weather patterns vary between summer and winter during summer synoptic winds are largely controlled by the combined effect of the north pacific anticyclone and the thermal low located over the southwestern united states resulting in persistent northwesterly winds a well defined marine atmospheric boundary layer mabl with properties distinct from the free atmosphere above is a conspicuous feature during the summer the wind has different characteristics in each of three zones maximum winds occur in the area extending south and east from pt conception zone 1 where they initially increase as they turn to follow the coast then decrease farther east winds are usually weak in zone 2 located in the easternmost part of the channel offshore from the oxnard plain winds are also weak in zone 3 sometimes reversing to easterly at night in a narrow band located along the mainland coast summer air temperature at the surface follows the sst closely and varies significantly with location summer sea level pressure gradients are large with the lowest pressure occurring on the northeast end of the santa barbara channel diurnal variations are strongest in summer although the modulation is weakest in zone 1 the diurnal variation is parallel to the coast in all of zone 3 but the oxnard plain where it is perpendicular to the coast the height of the marine layer varies between 300 m in late afternoon and 350 m in late morning in winter synoptic conditions are driven by traveling cyclones and sometimes accompanied by fronts these are usually preceded by strong southeast winds and followed by strong northwest winds atmospheric parameters are distributed more uniformly than in summer and diurnal variations are greatly reduced sea level air temperature and pressure are more spatially uniform than in the summer spatial variations in the observed fields in the summer are consistent with a hydraulic model of the mabl as a transcritical expansion fan the summertime situation is governed by a coupled interaction between the atmosphere and the underlying water the ocean influences the density of the mabl to the extent that it behaves distinctly from the free atmosphere above resulting in strong winds polarized in the direction parallel to the coast in turn these winds provoke an upwelling response in the coastal ocean which in part determines the surface properties of the water

tidal exchange at the bay ocean boundary for bays and inlets with narrow entrances tidal exchange with the ocean is often characterized by an ebb flood asymmetry in which the ebb flow exits the bay as a jet while the flood flow is drawn in approximately as a radial sink a process often termed tidal pumping in this paper the importance of tidal pumping in controlling the exchange of water at the bay ocean boundary is examined based on observations at the mouth of san diego bay the observations are novel in combining the use of shipboard acoustic doppler current measurements with a unique bay water tracer technique to provide visualization of the exchange as well as exchange budgets visualization of the tidal evolution of flow and tracers suggests that in accordance with the classical tidal pumping model the horizontal dynamics at the mouth of san diego bay are governed by an asymmetry between the jet like nature of the ebb flow and the sink like nature of the flood flow this asymmetry results in strong tidal velocity and phase gradients similar to those observed in previous numerical modeling studies a one dimensional trajectory model based on the observations indicates that the combined influence of the residual circulation and offshore gradients in the tidal velocity and phase provides the mechanism by which water from the bay is exchanged with water from the ocean both bottom friction and thermal gradients affect the dynamics of the vertical exchange the resulting asymmetry in the offshore flow leads to a vertical mode of pumping similar to that observed in the horizontal view this horizontal and vertical pumping of the offshore flow is shown to produce a strong correlation between the sectionally averaged velocity and bay water concentration resulting in a significant net tidal exchange between the bay and ocean

synthetic fluid inclusions xv tem investigation of plastic flow associated with reequilibration of fluid inclusions in natural quartz the nature and abundance of dislocations in quartz surrounding fluid inclusions were studied to obtain a better understanding of processes associated with fluid inclusion reequilibration synthetic fluid inclusions containing 10 wt nacl aqueous solution were formed in three samples at 700 c and 5 kbar one of the samples was quenched along an isochore to serve as a reference sample the other two samples were quenched along a p t path that generated internal pressures in excess of the confining pressure the two samples were held at the final reequilibration p t conditions of 625 c and 2 kbar for 30 and 180 days respectively following the experiments microstructures associated with fluid inclusions were examined with the tem quartz in healed fractures in the reference sample that was quenched isochorically shows a moderate dislocation activity quartz adjacent to reequilibrated fluid inclusions in the other two samples however showed a marked increase in dislocation activity compared to the un reequilibrated sample deformation of the inclusion walls occurred anisotropically by expansion of mobile dislocations in their slip systems dislocation expansion was controlled by glide in the rhombohedral planes 1 0 1 1 that was restricted to narrow zones 3 m in the immediate vicinity of the fluid inclusion walls outside of the healed fracture plane these plastic zones were observed after both short term 30 days and long term 180 days experiments and are attributed to hydrolytic weakening of quartz around fluid inclusions owing to diffusion of water into the quartz matrix during the experiment the close spatial association of submicroscopic water bubbles with dislocations and the rarity of water bubbles in the reference sample show clearly that in both the 30 and 180 day experiments reequilibration involves water loss from the fluid inclusions our results indicate that synthetic fluid inclusions in this study recover chemically and volumetrically even at relatively fast experimental loading rates such that internal stresses never reach the point of brittle failure the driving force for fluid inclusion deformation involves two related mechanisms plastic deformation of hydrolytically weakened wet quartz in the healed fracture and water leakage associated with preexisting and strain induced dislocations

the effect of porosity on the strength of quartz aggregates experimentally deformed in the dislocation creep regime abstract the presence of porosity results in significant although transient strengthening of quartz aggregates experimentally deformed in the dislocation creep regime experiments were conducted on four quartz aggregates with porosities of

a mechanism for preferential h 2 o leakage from fluid inclusions in quartz based on tem observations preferential leakage of h2o from fluid inclusions containing multiple gas components has been suspected in natural metamorphic rocks and has been demonstrated experimentally for synthetic h2o co2 rich inclusions in natural quartz knowledge of the physical and chemical characteristics of the leakage mechanism which may be very complex increases the value of natural fluid inclusions to metamorphic geology it is proposed that crystal defects play a major role in nondecrepitative preferential h2o leakage through quartz and remain effective during metamorphism inclusions with either an internal overpressure or underpressure produce strain in the adjacent quartz crystal via the nucleation of many dislocations and planar defects like dauphine twin boundaries these defects allow preferential loss of h2o from h2o co2 rich inclusions at supercritical conditions the transport capacity of this leakage mechanism is enhanced by nucleation of small bubbles on defect structures the nucleation of these bubbles seems to be a recovery process in strained crystals solubility gradients of quartz in water in a crystal with internally underpressurized inclusions may result in optical visible implosion halos in a three dimensional spatial arrangement caused by the growth of small bubbles at the expense of the larger original fluid inclusion natural fluid inclusions from naxos greece are always associated with numerous interlinked dislocations these dislocations may have been produced by plastic derormation or by crystal growth related processes e g crack healing the presence of small bubbles on these dislocations indicates that a similar leakage mechanism for h2o must have occurred in these rocks

mesoscale patterns in the cape sao vicente iberian peninsula upwelling region 1 the coastal upwelling region near cape sao vicente the southwestern tip of the iberian peninsula where the southern zonal coast meets the meridional western coast was studied using over 1200 advanced very high resolution radiometer avhrr satellite images of sea surface temperature and time series of sea level height wind velocities and nearshore sea surface temperature recorded at coastal sites within 200 km of the cape summer upwelling is more intense and persistent off the western coast than off the southern coast where a recurrent warm coastal countercurrent flows westward and at times turns northward along the western coast after reaching the cape in this region the equatorward current jet of cold water upwelled off the western coast is no longer bounded by a coast three preferred directions for the spreading of this water are identified the most persistent is eastward along the southern shelf break and slope possibly merging with waters previously upwelled locally which becomes separated from shore by the coastal progression of the warmer counterflow the second preferred direction results in the southward development of a cold filament feature fed by cold waters upwelled farther north and represents the southernmost extent of the intense coastal upwelling jet which overshoots the cape the least frequent feature to develop is a cold filament that grows westward at the latitude of the cape appearing to result from the meandering of the equatorward jet the coastal countercurrent is seen to interact with the equatorward jet at times of relaxation not only by separating the cold upwelled water from the coast but when it is energetic enough breaking westward offshore through the equatorward cold flow and separating the eastward and southward cold features from the upcoast cold waters empirical evidence shows the presence of an alongshore pressure gradient stronger in summer driving the coastal progression of the warm counterflow wind forcing plays an important role in the circulation by augmenting or diminishing the effect of the preexisting alongshore pressure gradients the extent of the progression of the warm coastal countercurrent along the southern and western coast is dictated by the the strength of the upwelling favorable wind stress which is able to balance and reverse the alongshore flow at least in the upper layers

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

experimental decrepitation and re equilibration of fluid inclusions in synthetic quartz abstract strong discrepancies between densities of the fluids trapped in fluid inclusions f i and p tp couples deduced from other geological considerations are common so it was decided to test experimentally the possible f i re equilibrations when bringing the host crystal in p tp conditions different from trapping conditions runs were conducted on synthetic quartz in a gas apparatus and in a griggs solid medium apparatus the following modifications of the f i were observed 1 1 drastic shape changes of the primary f i and appearance of clusters or trails of small secondary inclusions sometimes related to a crack 2 2 lowering of the fluid densities such a re equilibration is a decrepitation phenomenon first hydraulic fracturing then sealing of the cracks with appearance of secondary inclusions when using the gas apparatus the new measured densities are in very good accordance with the nominal p tp conditions when using the solid medium apparatus the new densities are surprisingly low relative to the nominal p t conditions probably due to a strongly anisotropic stress state in the apparatus

mesoscale surveys over the shelf and slope in the upwelling region near point arena california repeated mesoscale surveys of a 40 km wide 100 km long coastal region near point arena california were conducted during the upwelling season april august in 1981 and 1982 each survey included conventional conductivity temperature depth casts at standard locations over the continental shelf and slope between 38 n and 39 10 n and continuous operation of a doppler acoustic log to obtain velocity profiles in the 20 to 150 m depth range synoptic surveys covered the entire grid in 2 3 days winds were strongly favorable for upwelling during the three 1981 surveys and were weak or variable during the three 1982 surveys surface temperature and salinity fields reflect the influence of both the seasonal winds and day to day variations in the wind persistently low surface salinities offshore reflect the general southward advection of subarctic waters and sporadic low salinities over the inner shelf reflect north ward advection of local runoff through an intermittent narrow countercurrent along the coast circulation patterns during all but one of the surveys were very complex and included meandering equatorward flow cyclonic and anticyclonic eddies and inshore countercurrents the simple two dimensional equatorward baroclinic coastal jet usually associated with coastal upwelling was observed during only one of our surveys overall average fields are relatively simple they show broad equatorward surface flow a very weak inshore countercurrent and a definite poleward undercurrent at the shelf break average temperature salinity and density fields are generally congruent with the average flow pattern average isotherms and isohalines are not strictly parallel to the coastline south of the coastline bend at point arena they diverge gradually from the coast comparison of average sections calculated from 10 matched pairs of central and arena lines separated by 50 km shows there are systematic differences between them warmer fresher waters lie nearer shore and in shallower water off point arena than on the central line this suggests that the surface waters flowing past point arena have sufficient southward momentum to cross isobaths comparison of average velocity sections on these two lines shows some differences in structure since the variability is large these may not be significant comparison of the measured and geostrophic average shears suggests there is a significant ageostrophic component in the upper layers above 40 m it may be the signature of an average wind driven ekman spiral

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