process studies on the po river plume north adriatic sea the coastal processes in the adriatic sea and in particular the development and evolution of the po river plume are studied with a three dimensional primitive equation model experiments are performed to examine the buoyancy driven flow and the interaction with topography wind stress and ambient stratification the pathways of particles released from the po are computed to simulate the transport of land drained materials in the absence of wind forcing the po river plume consists of an offshore bulge that occupies most of the north part of the basin and a southward coastal current that is confined within the narrow coastal region along the italian peninsula when all adriatic rivers are included basinwide buoyancy driven cyclonic coastal flow is established that diminishes the seaward removal of po waters and promotes their southward advection through the coastal current wind stress modifies the above winds that are downwelling favorable for the po discharge site like bora restrict offshore plume development enhance the southward coastal current and confine the plume within the narrow western adriatic shelf conversely upwelling favorable winds like scirocco eliminate the baroclinic coastal current and advect low salinity po waters toward the shallow parts of the northern adriatic when preexisting stratification of basin waters is described the density field is influenced by both temperature and salinity during winter when the coastal waters tend to be colder and fresher than offshore waters the cyclonic circulation is sustained owing to input from rivers and particularly the po the intense spatial and temporal variability of wind stress and river runoff and the resulting variability in the circulation of the coastal adriatic sea are elaborated through a realistic simulation during january 1994

on the genesis of archean granite through two stage melting of the quetico accretionary prism at a transpressional plate boundary regional geologic relationships and geochemical data support the idea that late stage biotite granite of the lac la croix type may have formed by partial melting of previously migmatized metasedimentary rocks in the quetico subprovince of the superior craton the proposed parent material is an intimately layered rock composed of approximately half to two thirds biotite schist and half to one third granitoid leucosome the bulk chemical attributes of such a material were estimated from detailed mapping and drilling of two large outcrops near pearl lake minnesota previous work has demonstrated that the granitoid leucosome of the layered migmatite is the intrusively injected product of partial melting of a metasedimentary protolith therefore the proposed derivation of the younger lac la croix type granite from layered migmatite in effect represents a second distillation of granitic liquid from meta sedimentary rocks that had been enriched ingranitic components in the first cycle of partial melting and melt migration it is postulated that the implied two stage melting of metasedimentary rocks was related to thermal consequences within the quetico accretionary complex as tectonism along the quetico wabigoon boundary alternated between subduction and transform kinematics during late archean time

landform effect on rockfall and hazard mapping in cappadocia turkey the cappadocia region has unique geomorphological features resulting from differential erosional processes which make it very attractive to tourists besides the fairy chimneys for which the area is best known there are also impressive buttes and mesas buttes and mesas are formed in regions having flat lying strata in which the uppermost levels are composed of well cemented limestones and granular ignimbrites whereas the lower parts and slopes consist of low durability tuff and ignimbrites this durability difference results in serious rockfall events this study involves two dimensional rockfall analyses in and near the avanos zelve and cavusini areas where volcano sedimentary units of neogene age outcrop to provide a rockfall hazard map in which areas of tourism activity are also considered

estuarine plume a case study by satellite sar observations and in situ measurements estuary plumes on the western louisiana continental shelf in the gulf of mexico outside of constricted channels of the sabine and calcasieu lakes were observed on two radarsat 1 synthetic aperture radar sar images the in situ data showed a change in salinity of 2 3 psus across the front on the northwest edge of the plume corresponding to locations of vertical salinity variation of 5 5 7 5 psu velocity magnitude outside of the inlet reached more than 2 3 ms mathrm 1 seaward and a brackish lens in the upper 4 5 m of the water column the spread of which contributed to the development of a plume the volume of brackish water within the plume was estimated an order of magnitude larger than the volume output from the calcasieu river within an entire ebb tidal period this implies that the plume was formed during multiple tidal cycles and it sustained during the flood tides because only weak diurnal tides exist both satellite and in situ observations showed an interesting western intensification of the plume an analysis to the momentum vorticity equations suggests that the western intensification is due to the asymmetry of the vorticity divergence relationship under the coriolis force this can also be enhanced by an ambient coastal current that strengthens the convergence at the front estuary plumes are shown as bright and dark features in two sar images results from a radar model simulation and in situ water temperature data showed that the sar observed plume features were dominated by the water temperature differences

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

river plume sedimentation modeling for sequence stratigraphy application to the eel margin northern california abstract sediment deposition in the coastal zone from riverine input is of key importance in understanding the construction of sediment sequences through time a turbulent jet model is used to simulate sediment input to the continental margin from a riverine source turbulent jet models track the momentum which is the first order force carrying most of the sediment flowing into the ocean the froude number at the river mouth remains supercritical during floods of the eel river justifying the use of a jet model for the initial dispersion of the sediment laden plume sediment is deposited from the plume prior to the centerline froude number decreasing to its critical value empirically derived first order removal rate constants are used for each grain size in an advection diffusion equation to predict the areal extent of sediment deposition one strength of using a jet model is its ability to simulate deposits on a daily time step over intermediate time scales thousands of years using a limited number of input parameters a number of simulations of the eel river plume are shown for conditions of the present day and 18 000 yr bp during the last glacial maximum the model results for modern conditions show that a majority of the deposition occurs within 20 km north of the river mouth and is typically confined to within 10 km of the coastline corresponding well with the shelf sands on the eel margin however the initial mud deposit from a 1995 flood was farther offshore and northward additional advection of the mud fraction must occur after it leaves the surficial plume and prior to its initial deposition the model runs of 18 000 yr bp with 100 m lower sea level wetter and colder climate and the river mouth assumed to be at the canyon show that the plume is able to transport sand silt and clay out of the canyon and onto the continental slope

coastal circulations driven by river outflow in a variable density 1 layer model a variable density 1 layer model is used to investigate the dynamics of the fresher water plumes generated by river outflow solutions are found in a north south channel and the transport mr and salinity sr of the outflow are specified as boundary conditions along a 25 km wide segment of the western boundary in most cases the river water discharges into a preexisting oceanic mixed layer with thickness h1 when mr is sufficiently low plumes remain coastally trapped immediately after the outflow is switched on a coastal kelvin wave is excited at the river mouth that establishes a southward current of oceanic water along the right hand coast in contrast all the river water first bends to the left as it exits the river mouth and the resulting plume advances northward along the left hand coast at the plume nose some of the fresher water reverses direction and this water together with some oceanic water flows southward on either side of the offshore density front between the fresher and salty waters two processes cause this upstream movement geostrophic adjustment generates the southward frontal current and kelvin wave propagation from the nose thins the layer within the plume thereby establishing the northward geostrophic coastal jet when mr is sufficiently high coastally trapped plumes no longer exist if the rossby number of the outflow is also large enough the river water flows directly offshore and only a portion of it recirculates to form a northward propagating coastal plume the angle at which the outflow leaves the river mouth becomes more southward as mr and sr increase and as h1 decreases the strength of the northward propagating plume is weakened as h1 decreases and sr increases when h1 0 so that there is no ambient oceanic layer there is no northward plume at all likewise the plume is weakened when the model includes entrainment a process that acts to prevent the layer thickness from thinning appreciably

aegean surface circulation from a satellite tracked drifter array a pilot experiment using an array of 45 drifters to explore the circulation in the north and central aegean sea is described the global positioning system drifters with holey sock drogues provide positions every hour with data recovery through the argos system the drifters were launched in four separate deployments over a 1 yr period the resulting trajectories confirm the existence of a current around the rim of the basin consistent with a buoyancy plume created by the outflow of black sea waters through the dardanelles strait of canakkale in turkish the degree to which this is augmented by an ekman response to the dominant northerly winds is not obvious in the dataset owing to mesoscale dynamics that obscure the existence of any westward ekman flow the mesoscale eddy field involves anticylonic eddies in the current around the rim of the basin consistent with eddies with low salinity water cores cyclones are also seen with the most prominent forming over deep regions in the basin topography the array also documents the interaction of the currents with the straits through the sporades and cyclades island groups these interactions are complicated by the nature of the mesoscale flow and in some trajectories suggest a bernouilli acceleration in straits in others the flow through the island groups appears to be more diffusive and involves deceleration and eddy motions the rapid sampling by the drifters reveals an extremely nonlinear submesoscale eddy field in the basin with length scales less than 4 km and rossby numbers of order 1 a better understanding of the dynamics of these features is of importance for understanding the circulation of the basin

pattern of sediment transport in a microtidal river mouth using geostatistical sediment trend analysis abstract we perform a grain size trend analysis gsta to investigate sediment transport mechanisms in the grand rhone microtidal mouth during various hydroclimatic conditions the objective is to determine the efficiency of this method to explain the directions of residual transport pattern and mode of distribution of the fluvial sediment input in an environment that is very difficult to equip with instrumentation during extreme events the known biases of this sedimentological approach are reduced by using enriched geostatistical processing and choosing periods of sampling subject to unequivocal hydrodynamic forcings the modeling results and grain size distributions of surface sediments clearly show three vector fields during periods of low river discharge the first vector field corresponds to an upstream zone under fluvial influence the second field is characteristic of a mixing zone confined inside the river mouth and marked by heterogeneous sedimentation this sector is interpreted as the confrontation zone between alluvial and marine dynamics farther offshore the vectors are oriented towards the river and at counter slope in deeper zones the vectors reflect the sediment transport generated by wave refraction at the top of the mouth bar at the delta front bathymetry from 5 m to 20 m the vectors are interpreted as representing a lag deposit the periods of medium and extreme floods are associated with storms the marine dynamic regime generates a longshore drift current which brings sediments onto the mouth bar during medium flood events only the inner part of the mouth bar is highly influenced by the river during extreme flood events the river influences both the eastern part of the mouth and the wave regime in the central part consequently the gsta method shows that even during flood events the river solid discharge is not transferred towards the adjoining upper shoreface in the context of a wave dominated delta the distribution of surface sedimentation in a microtidal mouth remains controlled mainly by the swell even in periods of flood when the intensity of river dynamics is exacerbated finally all these results are similar to the known hydro sedimentological behaviours of the rhone river mouth nevertheless gsta results seem not self sufficient to explain all the processes but this method proposes an alternative approach to traditional methods used to measure bed load sediment transfer during extreme events

dynamics of an equatorial river plume theory and numerical experiments applied to the congo plume case abstractthe congo river has the second largest rate of flow in the world and is mainly responsible for the broad tongue of low salinity water that is observed in the gulf of guinea despite their importance near equatorial river plumes have not been studied as thoroughly as midlatitude plumes and their dynamics remain unclear using both theory and idealized numerical experiments that reproduce the major characteristics of the region the authors have investigated the dynamics of the congo river plume and examine its sensitivity to different forcing mechanisms it is found that near equatorial plumes are more likely to be surface trapped than midlatitude plumes and the importance of the effect in describing the strong offshore extent of the low salinity tongue during most of the year is demonstrated it is shown that the buoyant plume constrained by the geomorphology is subject to the pulling of nonlinear structures and wavelike equatorial dynamics the wind is found to strengthen the intrinsic buoy

river forced estuarine plumes abstract the development maintenance and dissipation of river forced estuarine plumes with and without seaward sloping bottom are studied by use of a three dimensional primitive equation model inside the estuary discussion is focused on how the coriolis force induces lateral asymmetries in the circulation four physical processes dictate the transient as well as the quasi steady circulation in moderately stratified estuaries 1 upper layer convergence during the transient spinup phase 2 upward entrainment leading to the two layer steady circulation pattern 3 upward stretching of the lower layer vortex during the spindown period and 4 in the presence of a seaward bottom slope the left bounded tendency of the landward undercurrent for all phases of development deviations from the laterally averaged circulation pattern caused by these processes are discussed over the shelf various types of plumes are defined according to the visual appearance of the surface salinity field the four types of p

tidal modulation on the changjiang river plume in summer 1 tide effects on the structure of the near field changjiang river plume and on the extension of the far field plume have often been neglected in analysis and numerical simulations which is the focus of this study numerical experiments highlighted the crucial role of the tidal forcing in modulating the changjiang river plume without the tidal forcing the plume results in an unrealistic upstream extension along the jiangsu coast with the tidal forcing the vertical mixing increases resulting in a strong horizontal salinity gradient at the northern side of the changjiang river mouth along the jiangsu coast which acts as a dynamic barrier and restricts the northward migration of the plume furthermore the tidal forcing produces a bidirectional plume structure in the near field and the plume separation is located at the head of the submarine canyon a significant bulge occurs around the head of the submarine canyon and rotates anticyclonically which carries a large portion of the diluted water toward the northeast and merges into the far field plume a portion of the diluted water moves toward the southeast which is mainly caused by tidal rectification this bidirectional plume structure is more evident under certain wind conditions during the neap tide with the reduced tidal energy the near field plume extends farther offshore and the bulge becomes less evident these dynamic behaviors are maintained and are fundamentally important in the region around the river mouth even under the summer monsoon and the shelf currents although in the far field the wind forcing and shelf currents eventually dominate the plume extension

the columbia river plume study subtidal variability in the velocity and salinity fields a comprehensive study of the strongly wind driven midlatitude buoyant plume from the columbia river located on the u s west coast demonstrates that the plume has two basic structures during the fall winter season namely a thin 5 15 m strongly stratified plume tending west to northwestward during periods of southward or light northward wind stress and a thicker 10 40 m weakly stratified plume tending northward and hugging the coast during periods of stronger northward stress the plume and its velocity field respond nearly instantaneously to changes in wind speed or direction and the wind fluctuations have timescales of 2 10 days frictional wind driven currents cause the primarily unidirectional flow down the plume axis to veer to the right or left of the axis for northward or southward winds respectively farther downstream currents turn to parallel rather than cross salinity contours consistent with a geostrophic balance in particular during periods when the plume is separated from the coast currents tend to flow around the mound of fresher water at distances exceeding about 20 km from the river mouth the along shelf depth averaged flow over the inner to midshelf is linear and depth averaged acceleration is governed to lowest order by the difference between surface and bottom stress alone in this region along shelf geostrophic buoyancy driven currents at 5 m calculated from surface density and along shelf geostrophic wind driven currents computed from a depth averaged linear model are comparable in magnitude 10 25 cm s 1

bathymetric effects on estuarine plume dynamics 1 the influence of bathymetry on an estuary plume at an estuary shelf transition is studied with a three dimensional ocean circulation model to understand the response of the plume to bathymetry several types of estuarine shapes and shelf geometries were adopted in this numerical study the channel s shape and its width to depth aspect ratio affected the fate of the plume by determining flow characteristics inside the estuary moreover the bathymetry of the shelf such as the shelf slope and the direction of a submarine channel defined the plume characteristics on the shelf an estuarine channel with a triangular cross section generated relatively stronger exchange flows at midestuary than a rectangular cross section which resulted in a larger surface plume over the shelf the extension of the submarine channel onto the shelf favored increased plume water transport out to the shelf a result of reduced frictional effects on the shelf the orientation of the submarine channel changed the direction of the plume over the shelf with no additional external forces two fronts developed at the edges of the submarine channel because of enhanced lateral shears in the flow when the estuary was relatively wide compared to the internal rossby radius kelvin number ke 5 or when the relative strength of the freshwater discharge compared to the estuary width was weak rossby number ro 0 05 the coastal plume did not expand up shelf in fact results indicated that freshwater up shelf transport in a coastal current moving against coriolis accelerations was proportional to ro

circulation on the western south atlantic continental shelf 1 numerical process studies on buoyancy 1 buoyancy driven currents are investigated in the western south atlantic ocean where a major river plume la plata interacts with a minor one patos lagoon a series of simulations were performed with a three dimensional free surface numerical model to better understand the processes which control both plumes evolution and their interaction the simulations are focused on the importance of turbulent mixing to the evolution of the la plata plume and its downshelf penetration toward the patos lagoon satellite observations and historical data show that the la plata plume has a tendency to expand along the river southern margin before it turns north in the direction of coastal trapped waves propagation our results on the other hand show that in the absence of the tides and the wind this plume tends to leave the estuary attached to its northern margin downstream unless the model parameters are tuned to produce unrealistically high turbulent mixing we then address the role of each parameter that controls mixing and show that by tuning the model parameters we can get plumes similar to those observed in nature however the plumes produced in the experiments with excessively high mixing parameters showed unbounded southward upstream expansion by introducing the tides we show that the plumes produced in the presence of tidal stirring and normally set mixing parameters are more realistic suggesting that tidal stirring is more effective than artificially tuned turbulent mixing on causing the plume lateral expansion

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

scaling analysis for the interaction between a buoyant coastal current and the continental shelf experiments and observations abstract this paper addresses how the geometrical parameters ambient ocean depth h bottom slope of coastal bathymetry affect the evolution of buoyant coastal currents flowing over a sloping continental shelf scaling arguments are presented that show the coastal current dynamics can be classified by a two variable nondimensional parameter space the ambient depth parameter h h and the bottom slope parameter r yb the ratio h h is the fraction of the available depth occupied by the buoyant layer the bottom slope parameter is the ratio of two horizontal length scales the internal rossby radius r to the bottom trapped width yb the scale depth h is derived from geostrophic dynamics and is representative of the depth of the buoyant layer of the coastal current the resulting parameter space is delineated by surface advected currents that do not depend upon the bottom slope parameter and bottom trapped currents that do for bottom trapped coastal currents the across shore width and downstream velo

wind forcing controls on river plume spreading on a tropical continental shelf the berau continental shelf is located close to the equator in the indonesian archipelago hosting a complex of coral reefs along its oceanic edge the berau coral reefs have a very high biodiversity but the area is under serious risk due to river derived nutrients and sediments the region is characterized by weak winds moderate tides and almost absent coriolis forcing existing knowledge about river plume behavior in tropical environments is limited the aim of this paper is to investigate the influence of the subtle physical forcing on the dynamics of the berau river plume a three dimensional model ecomsed was calibrated with observational data the model was forced by freshwater input from the berau river distributaries tides at the open boundaries and measured hourly wind the model reproduces the freshwater dynamics on the shelf adequately and highlights that the river plume spreads symmetrically for river forcing only tides cause vertical mixing and suppress the cross shelf spreading of the river plume however the spreading of the river plume over the shelf is mainly controlled by the weak monsoonal winds resulting in a seasonal development during the southeast monsoon the southerly winds push the plume northeastward and cause a stratified water column in the northern part of the continental shelf northerly winds during the northwest monsoon disperse the plume to the south promoting a vertically well mixed water column the results can be used to predict the possible impact of land use changes in the steadily developing berau region on coral reef health

the siberian coastal current a wind and buoyancy forced arctic coastal current we describe circulation and mixing in the siberian coastal current scc using fall shipboard measurements collected between 1992 and 1995 in the western chukchi sea the scc forced by winds siberian river outflows and ice melt flows eastward from the east siberian sea it is bounded offshore by a broad 60 km front separating cold dilute siberian coastal water from warmer saltier bering sea water the alongshore flow is incoherent because the current contains energetic eddies and squirts probably generated by frontal baroclinic instabilities these enhance horizontal mixing and weaken the cross shore density gradient along the scc path eventually the scc converges with the northward flow from bering strait whereupon it deflects offshore and mixes with that inflow deflection occurs where the alongshore pressure gradient vanishes that location varies on synoptic and seasonal timescales because this gradient depends on the winds buoyancy fluxes and the sea level difference between the pacific and arctic oceans deflection usually occurs on the chukchi shelf but the scc occasionally flows southward through bering strait such events are short lived 1 10 days and occur mainly in fall and winter under northerly winds scc transport is likely small 0 1 sv but its dilute waters could substantially freshen the bering strait inflow and affect the disposition of pacific waters in the arctic ocean arctic river outflows should preferentially form surface advected fronts rather than bottom advected fronts because vertical mixing energy is low on arctic shelves surface advected fronts are more susceptible to upwelling winds and for the scc the pressure gradient between the pacific and arctic oceans than bottom advected fronts the scc never developed in fall 1995 because of anomalously steady upwelling winds the western chukchi shelf could have formed upper halocline source water in the winter of 1995 1996

water and sediment dynamics in the red river mouth and adjacent coastal zone abstract the coastline of the red river delta is characterized by alternating patterns of rapid accretion and severe erosion the main branch of the red river the ba lat is presently expanding seaward with a main depositional area several km downstream and offshore the ba lat river mouth sediment deposition rates are approximately 6 m in the past 50 years field measurements were done to determine the processes that regulate marine dispersal and deposition of sediment supplied by the ba lat these measurements reveal that the waters surrounding the ba lat delta are strongly stratified with a pronounced southward flowing surface layer this southward flowing surface layer is a coastal current which is generated by river plumes that flow into the coastal zone north of the ba lat however outflow of turbid river water is not continuous and most sediment enters the coastal zone when the alongshore surface velocities are low as a consequence most sediment settles from suspension close to the river mouth in addition to the southward surface flow the southward near bottom currents are also stronger than northward currents contrasting with the residual flow near surface this southward flow component near bottom is caused by tidal asymmetry because most sediment is supplied by the ba lat when wave heights are low sediment is able to consolidate and therefore the long term deposition is southward of but still close to the ba lat mouth

straining and advection contributions to the mixing process of the patos lagoon coastal plume brazil 1 the southern brazilian shelf is a region influenced by freshwater and the evolution of stratification can present important ecological consequences in this area the aim of this paper was to investigate the importance of straining and advection processes that affect the stratification and destratification of the water column along the southern brazilian inner shelf a region that is influenced by the patos lagoon coastal plume the study was carried out through 3 d numerical modeling experiments and the results were analyzed using the potential energy anomaly equation and wavelet analysis results showed that the potential energy anomaly showed strong variability over a time scale of several days and followed the wind pattern over the study region and was accompanied by the monthly modulation of river discharge and remote effects associated with variability in oceanic circulation however the most important events in synoptic time scales occurred in periods shorter than 20 days and were coincident with the passage of meteorological systems over the study region straining and advection were the most important mechanisms for the evolution of stratification in the adjacent coastal region nonlinearities and dispersion terms were as important as modulation effects mainly during periods of high fluvial discharge close to the patos lagoon mouth vertical advection explained most of the stratification evolution due to the morphological characteristics in this region in the frontal region and far field of the plume the following two regions must be considered the northeast part which is characterized by the convergence of the coastal currents and ebb flows associated with the freshwater discharge that promote the domination of the cross shore straining and advection and the southwest part which is controlled by the coastal currents that result in the domination by alongshore straining and advection and cross shore advection terms close to the mouth of the patos lagoon the occurrence of downward velocities generated downward displacement of the isopycnals which decreases the potential energy anomalies and vice versa near the frontal region the anomalies were dependent on the intensity of the fluvial discharge during moderate to high discharge events the northeastward currents intensified mixing along shore which decreased the potential energy anomalies in the same way the southwestward currents intensified the spreading of freshwater and increased the stratification and the potential energy anomalies

impact of variable inflow on the dynamics of a coastal buoyant plume the impact of buoyant discharge variations on the dynamics of coastal buoyancy driven currents is studied using a primitive equation numerical model spem5 first variable discharge is introduced as harmonic fluctuations of the inflow velocity at the tidal period 12 hours and subinertial period 10 days frequencies tidal fluctuations produce only minor effects on the buoyant plume compared to the case of constant inflow while subinertial fluctuations substantially modify the anticyclonic bulge a partially detached anticyclonic plume forms when discharge subsides after reaching its peak value such a plume has maximum offshore extension some distance downstream of the mouth with the lightest water separated from the coast a secondary bulge forms during the low runoff interval when high discharge resumes this secondary bulge is shifted offshore and enhanced for some time an individual high discharge event is next considered where both the net transport of the inflow and the absolute value of its density anomaly increase and then return to their initial background values over 5 and 10 day time intervals this event also generates a partially detached plume especially with the 10 day duration in this case the lightest water occupies the downstream part of the bulge and is separated not only from the coast but also from the mouth the effect of variable discharge is more dramatic with a uniform downstream current of 0 1 m s under such conditions constant buoyant discharge does not form a well pronounced anticyclonic bulge in contrast variable discharge produces an almost circular anticyclone during the high runoff interval as runoff decreases this anticyclone separates from the source and either continues to propagate downstream as an individual eddy or is modified by the next cycle of increasing discharge observational evidence for both the partially detached bulge near the mouth and the anticyclone propagating downstream from its source is presented in this study one feature was observed at the mouth of the columbia river estuary the second feature was observed off the southern new jersey coast 150 km south of its source the hudson estuary

subtidal flow structure at the turning region of a wide outflow plume 1 a series of underway current velocity profiles and near surface temperature and salinity measurements were combined with temperature and salinity profiles to characterize the subtidal flow structure at the turning region of a wide plume the chesapeake bay outflow plume in this context wide refers to the ratio of lateral plume expansion to internal radius of deformation being greater than one observations were obtained in september and november of 1996 and in february and may of 1997 with the idea of capturing the variability in forcing conditions typically associated with these seasons however regional precipitation patterns yielded similar buoyancy forcing conditions for the four surveys and among the wettest years on record this buoyancy forcing produced a well delineated outflow plume that separated from the coast on its way out the estuary the plume separation acted in conjunction with frictional effects to delineate an inshore front in addition to the customarily described offshore front the outflow plume was markedly constrained by the chesapeake channel which was also the main conduit of shelf waters toward the estuary the bathymetric influence was also evident in the surface salinity field the mean flows and the volume fluxes the offshore extent of the plume was found between the scale predicted by geostrophic dynamics internal rossby radius and that predicted by cyclostrophic dynamics such offshore extent was most likely linked to the plume interactions with the bathymetrically steered up estuary flow this was corroborated by an analytical solution that explored the dynamical balance among pressure gradient coriolis accelerations and friction in addition to being influenced by bathymetry the chesapeake bay outflow plume was modified by local and remote effects related to atmospheric forcing

evolution of a buoyant outflow in the presence of complex topography the dardanelles plume north aegean sea 1 the outflow of waters of black sea origin bsw through the dardanelles strait is the strongest buoyant input for the north aegean sea nas two opposing flows exist across the dardanelles exit a lighter upper layer outflow bsw and a denser deeper layer inflow waters of mediterranean origin this study examines the processes influencing the plume development and evolution the complex topography of the receiving basin nas plays a significant role on the preferred bsw pathways that are controlled by the buoyancy and wind forcing a high resolution numerical model the nas hycom hybrid coordinate ocean model is implemented to perform process oriented experiments that examine the relative role of the forcing factors and topographic effects three major pathways are identified in the absence of wind an anticyclonic bulge is formed inducing a westward jet that is topographically guided between two islands near the outflow topography also controls the development of a buoyancy driven coastal current and a rim current along the north aegean shelf areas comparison of model results to analytical calculations suggests that topography modifies the formation and the ballooning of the anticyclonic bulge which are controlled by the outflow rate the resulting stratification and coriolis experiments also employ several wind directions and magnitudes in combination with different outflow characteristics the study elucidates the importance of the aegean morphology on the processes controlling the coupling to the black sea the bsw are found to influence both deep and shelf aegean basins along their overall cyclonic pathway toward the eastern mediterranean

influence of a river plume on coastal upwelling dynamics importance of stratification abstractsatellite images show that the pearl river plume is entrained into the upwelling front in the northeastern south china sea to understand the processes and extend to other coastal zones an