enhancement of alongshore freshwater transport in surface advected river plumes by tides abstracta recent numerical study by isobe showed that imposing alongshore tidal forcing on buoyant coastal discharge enhances the net freshwater transport in the coastal currents the mechanisms for this transport enhancement are studied using a three dimensional primitive equation ocean model regional ocean modeling system roms lagrangian drifters are used to trace the freshwater transport paths it is found that the river plume bulge circulation largely follows the rigid body motion i e constant vorticity the buoyant fluid near the bulge s outer edge is thinner and faster behaving as a baroclinic jet the bulge currents then split after impinging on the coast the outer fluid feeds the downshelf flowing coastal currents while the inner fluid recirculates to form the bulge the coastal current transport estimated from the present and prior studies corresponds well to a baroclinic jet theory with the incident angle of bulge currents at the coast being a key parameter without tides the bulg

progress on upwelling studies in the china seas east asian marginal seas surrounding china exhibit rich ocean upwelling mostly in response to the southwesterly summer monsoon upwelling in the china seas namely the south china sea the taiwan strait the east china sea the yellow sea and the bohai sea has become increasingly important because the potential changes in the upwelling may have dramatic ecosystem socioeconomic and climate impacts this paper reviews the progress of upwelling studies in the china seas since the year 2000 by presenting the principal characteristics and new understanding of 12 major upwelling regions in the china seas upwelling exhibits long term variability at intraseasonal to multi decadal scales as well as short term variability frequently caused by tropical cyclones it is also associated with the el nino southern oscillation local environmental variation and biogeochemical factors the coastal upwelling around hainan island and the upwelling or cold dome northeast of taiwan island are specifically highlighted because they have attracted great interest for decades this paper summarizes upwelling mechanisms in terms of wind topography tide stratification and background flow with applications mostly to the china seas finally we propose some topics for future upwelling research i e potential intensification of coastal upwelling under global climate change downwelling intrusion of upwelling into coastal embayments and the influence of upwelling on fishery and biogeochemical processes

the dynamics of the mississippi river plume impact of topography wind and offshore forcing on the fate of plume waters 1 high resolution numerical simulations of the northern gulf of mexico region using the hybrid coordinate ocean model hycom were employed to investigate the dynamical processes controlling the fate of the mississippi river plume in particular the conditions that favor cross marginal transport the study focuses on the effects of topography wind driven and eddy driven circulation on the offshore removal of plume waters a realistically forced simulation nested in a data assimilative regional gulf of mexico hycom model reveals that the offshore removal is a frequent plume pathway eastward wind driven currents promote large freshwater transport toward the shelf break and the desoto canyon where eddies with diameters ranging from 50 to 130 km interact with the buoyant plume and effectively entrain the riverine waters our estimates show that the offshore removal by eddies can be as large as the wind driven shelf transport the proximity of eddies to the shelf break is a sufficient condition for offshore removal and shelf to offshore interaction is facilitated by the steep bottom topography near the delta strong eddy plume interactions were observed when the loop current system impinged against the shelf break causing the formation of coherent narrow low salinity bands that extended toward the gulf interior the offshore pathways depend on the position of the eddies near the shelf edge their life span and the formation of eddy pairs that generate coherent cross shelf flows this study elucidates the dynamics that initiate a unique cross marginal removal mechanism of riverine low salinity nutrient rich waters allowing their export along connectivity pathways induced by a large scale current system

reconstruction of late paleozoic heat flows and burial histories at the rhenohercynian subvariscan boundary germany the thermal and burial history of the herzkamp syncline located in the transition zone between the variscan rhenish massif and the ruhr foreland basin western germany was reconstructed using pdi pc 1d basin modelling software ies the models were calibrated with new vitrinite reflectance data measured on palaeozoic outcrop samples high sample density and quality of the calibration data allowed a 3d reconstruction of the heat flow as well as of burial and erosion history vitrinite reflectance values range from 0 8 to 4 9 rr and generally increase with increasing stratigraphic age the coalification pattern confirms pre tectonic maturation especially in the western part of the study area a low coalification zone showing stagnating decreasing coalification with increasing stratigraphic age exists however northeast of the ennepe thrust indicating synorogenic coalification this anomaly is explained by early thrusting in the northern rhenish massif resulting in restricted burial early uplift and thus lower thermal maturity one result of numerical modelling is that palaeo heat flows during maximum burial westphalian or post westphalian decreased southwards from approximately 65 to less than 50 mw m2 maximum burial depths for the base and top of the namurian also decrease southwards from 7000 to 3600 m and 4600 to 1800 m respectively resulting in southwards decreasing coalification of the respective stratigraphic horizon eroded overburden increases southwards 3100 5700 m with the exception of the low coalification zone which is characterised by lower amounts of eroded overburden 1300 2900 m and an earlier onset of erosion i e in the westphalian b rather than westphalian d or post westphalian

numerical modelling of burial and temperature history as an approach for an alternative interpretation of the bramsche anomaly lower saxony basin the lower saxony basin germany is one of the several sedimentary basins within the central european basin system in its southwestern part anomalously high maturity of organic matter has been observed to reach 4 5 vrr in upper jurassic and lower cretaceous sedimentary rocks in an area which coincides with a magnetic and a positive gravimetric anomaly this anomaly was often interpreted as the consequence of a deep seated igneous intrusion the so called bramsche massif however results obtained from calibrated numerical modelling are not in accordance with this scenario instead a burial by approximately 4 km of now eroded cretaceous rocks was revealed to be the probable cause for the anomaly data and modelling results from six boreholes and two pseudo wells support this view

a census of eddy activities in the south china sea during 1993 2007 1 numerous mesoscale eddies occur each year in the south china sea scs but their statistical characteristics are still not well documented a pacific basin wide three dimensional physical biogeochemical model has been developed and the result in the scs subdomain is used to quantify the eddy activities during the period of 1993 2007 the modeled results are compared with a merged and gridded satellite product of sea level anomaly by using the same eddy identification and tracking method on average there are about 32 9 2 4 eddies predicted by the model and 32 8 3 4 eddies observed by satellite each year and about 52 of them are cyclonic eddies the radius of these eddies ranges from about 46 5 to 223 5 km with a mean value of 87 4 km more than 70 of the eddies have a radius smaller than 100 km the mean area covered by these eddies each year is around 160 170 km2 equivalent to 9 8 of the scs area with water depths greater than 1000 m linear relationships are found between eddy lifetime and eddy magnitude and between eddy vertical extent and eddy magnitude showing that strong eddies usually last longer and penetrate deeper than weak ones interannual variations in eddy numbers and the total eddy occupied area indicate that eddy activities in the scs do not directly correspond to the el nino southern oscillation events the wind stress curls are thought to be an important but not the only mechanism of eddy genesis in the scs

dispersal of the pearl river plume over continental shelf in summer abstract satellite images of turbidity were used to study the climatological monthly and typical snapshot distributions of the pearl river plume over the shelf in summer from 2003 to 2016 these images show that the plume spreads offshore over the eastern shelf and is trapped near the coast over the western shelf eastward extension of the plume retreats from june to august monthly spatial variations of the plume are characterized by eastward spreading westward spreading or both time series of monthly plume area was quantified by applying the k mean clustering method to identify the turbid plume water decomposition of the 14 year monthly turbidity data by the empirical orthogonal function eof analysis isolated the 1st mode in both the eastward and westward spreading pattern as the time series closely related to the pearl river discharge and the 2nd mode with out of phase turbidity anomalies over the eastern and western shelves that is associated with the prevailing wind direction eight typical plume types were detected from the satellite snapshots they are characterized by coastal jet eastward offshore spreading westward spreading bidirectional spreading bulge isolated patch offshore branch and offshore filaments respectively their possible mechanisms are discussed

rock mechanical investigations of seismic events in a deep longwall coal mine seismic events i e fractures in rock that radiate detectable seismic waves are a worldwide phenomena associated with mining and reservoir exploitation longwall mining in german coal mines often causes seismic events which can be felt at surface where they can lead to a considerable annoyance of residents and sometimes even lead to minor damages of buildings and infrastructure strong seismic events are in a large part responsible for a more and more decreasing community acceptance of mining the mines therefore have to investigate the local conditions which cause the generation of seismic events to find ways of avoiding strong mining induced seismic events this paper describes the research on mining induced seismicity around a specific active longwall at 1100 m depth under several previously mined longwall panels seismic events are recorded by a local network featuring 15 surface and six subsurface stations location and fault plane solutions show the occurrence of at least three different event types which are characterized by distinct modes of failure underground core drilling and an extensive rock testing program are used to build up a rock mechanical model featuring a multi layer strata for use with numerical analyses the numerical model is able to explain the different failure mechanisms as fault activation remnant pillar punching and beam failure the use of rock mass classification rock mass strength criteria and in situ stresses together with 2d and 3d numerical analyses facilitates the evaluation of the results from seismology approaches and makes future analysis of longwall related seismic events possible

upwelling in the taiwan strait during the summer monsoon detected by satellite and shipboard measurements the taiwan strait is located at the confluence of the east china sea and the south china sea in the west pacific ocean several upwelling zones in the taiwan strait are noted for their high fisheries production these upwelling zones have been studied in the past decade but we have no overall picture on the size and temporal changes of these upwelling zones due to only limited in situ observation over short periods of time the present paper investigates upwelling in the taiwan strait with satellite remote sensing data of noaa derived sea surface temperature sst and seawifs derived chlorophyll a chl a and shipboard measurements during summer 1998 results reveal five upwelling zones 1 coastal upwelling near pingtan island ptu 2 coastal upwelling between meizhou and xiaman mxu 3 big coastal upwelling near dongshan island dsu sometimes extending to offshore 4 small occasional upwelling near the penghu island phu and 5 an intensive upwelling in the taiwan bank tbu tbu was extensively studied over summer 1998 results showed that the tbu looks like a banana in shape in the southern edge of the taiwan bank it intensifies in its southeastern edge the size of tbu was about 2500 3000 km 2 with a mean value of 2796 km 2 the temperature difference between the upwelling and non upwelling areas was about 2 5 3 5 jc for early august with a mean value of 2 3 jc on july to october series of images indicated a short term variation of tbu and showed that high chl a concentrations up to 0 8 2 mg m 3 zones coincided with low sst 25 26 jc zones in terms of location time and shape these upwelling zones change with size and intensity center from time to time field measurements of water temperature salinity and chl a in 1998 are consistent with satellite measurements d 2002 elsevier science inc all rights reserved

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

development of upwelling on pathway and freshwater transport of pearl river plume in northeastern south china sea in situ observations satellite images and numerical modeling results have shown that the pearl river plume axis extends alongshore and passes through two separate upwelling regions one off the guangdong and fujian coasts the yuedong upwelling and the other in the taiwan bank during the initial and medium stages of the yuedong upwelling while it is directed offshore when the yuedong upwelling is fully developed model experiments are conducted to examine the effects of wind strength and baroclinicity on the upwelling and the corresponding pathway and freshwater transport of the pearl river plume the baroclinic effect is important to intensifying the horizontal velocity at the upwelling front and freshwater transport in the northeastern south china sea the freshwater transport flux is further decomposed into advection vertical shear and tidal pumping components and advection is the dominant contributor as the yuedong upwelling develops the zone with a relatively high pressure gradient moves offshore due to offshore ekman transport and the shift in the upwelling front which is responsible for the offshore transport of the river plume when the river plume is transported to the outer shelf sometimes it can be further entrained into eddies allowing its export to the open sea

mesoscale eddies in the northern south china sea a fine grid resolution model with realistic bathymetry and forcing has been developed to study the characteristics of the mesoscale eddies for the northern south china sea scs the scs model derives its open boundary conditions from a larger scale model which minimizes errors related to the uncertainty of the kuroshio intrusion at the open boundaries the model results are consistent with previous observations model sea surface height anomaly demonstrates that the hydrography and circulation in the northern scs are modulated by westward propagating mesoscale eddies originating in the vicinity of the luzon strait this explains the observed intra seasonal fluctuations at the southeast asian time series study seats station the mesoscale eddies have the same propagation speed as baroclinic rossby waves 0 1 ms 1 the periods of eddy shedding estimated from strouhal number are around 40 50 days in december and 80 120 days in august respectively the seasonal variability of the kuroshio intrusion results in more eddies in winter than in summer r 2007 elsevier ltd all rights reserved

coastal upwelling in summer 2000 in the northeastern south china sea using a combination of hydrographic tide gauge near bottom mooring and satellite observations and a numerical circulation model we investigate the coastal upwelling in the northeastern south china sea nscs off the coast of fujian and guangdong provinces china in the summer of 2000 subsurface upwelling phenomenon exists mainly near the bottom boundary in the whole region investigated it is closely related to the coastal sea level fluctuations which are evidently modulated by both the local wind forcing and the large scale circulation the northeastward interior flow following the bathymetry is accelerated by the drop of coastal sea level and leads to onshore transport and subsequent cooling in the bottom boundary layer bbl over the shelf west of shantou to the east of shantou the near bottom flow veers more eastward parallel to the coastline and transports the nearshore cold water mass farther to the southern fujian coast the cross shelf advected cold water does not always penetrate through the stratification and reach the surface the local wind exhibits considerable synoptic variability the decrease in sea surface temperature sst is mostly significant near dongshan shantou intermittent in time and intensifies preferably during weather events that bring southwesterly alongshore wind to the west a freshwater tongue originating from the pearl river forms a barrier layer which results in high surface temperature in the freshwater plume the observational evidences and modeled results shown in this study provide important information for further understanding the ecological effects associated with the upwelling processes in the nscs

tide induced mixing in the amazon frontal zone the freshwater discharge from the amazon river produces a bottom salinity front on the amazon shelf that extends many hundreds of kilometers along the shelf between the 10 and 20 m isobaths strong cross shelf tidal currents cause advective excursions of the front of more than 20 km and supply the major source of kinetic energy for mixing on the shelf this mixing is manifested in spring neap variations in the frontal structure and position with weaker stratification and seaward migration of the front during periods of strong tidal currents and stronger stratification and landward migration during neap tides mixing appears to be driven by shear instability based on local estimates of gradient richardson number and bulk estimates of the water column stability maximum mixing occurs during ebb when vertical shear is greatest suspended sediment reaches such high concentrations in the frontal zone that it makes a significant contribution to the stratification thus increasing the stability of the flow and reducing the effectiveness of tide induced mixing

intensified upwelling over a widened shelf in the northeastern south china sea 1 observational and three dimensional modeling studies reveal that the intensified upwelling in the northeastern south china sea nscs is formed as a result of intensified upslope advection of dense deep waters that cross the middle shelf toward the inner shelf over a distinctly eastward widened shelf the strongest advection occurs over the converging isobaths near the head of the widened shelf as these dense deep waters advance shoreward they are advected downstream by the quickly developed upwelling current over the inner shelf and eventually outcropped at the lee of a coastal cape dynamically the shoreward cross isobath transport over the widened shelf is geostrophically enhanced by a quasi barotropic negative westward along isobath pressure gradient force as a result of the net rate of the momentum influx and by an intensified bottom frictional transport owing to the flow confluence near the head of the widened shelf a negative pressure gradient also exists at the lee of the coastal cape over the inner shelf and locally amplifies shoreward motion induced by the respective widened shelf and the coastal promontory the along isobath variations of cross isobath transport in the water column over the middle and inner shelves interactively characterize intensified upwelling in the nscs

observations and numerical modeling of the pearl river plume in summer season a cruise survey of the pearl river plume during southeasterly and southwesterly winds two typical wind patterns in summer in guangdong coastal waters is reported and the cruise data are analyzed to unveil the plume dynamics the kelvin number is derived from the in situ data revealing that the pearl river plume exhibits two different scales in response to the two kinds of the wind forcing numerical model simulations based on the regional oceanic modeling system roms with nesting domains are implemented to explore details of the plume dynamics validated by cruise observations and tidal gauge sea level data modeling results suggest that there is a subtidal anticyclonic recirculation bulge on the west side out of the estuary mouth under southeasterly winds showing a recirculating plume in the near field when the wind changes to the southwesterly however the recirculating plume vanishes the distinct supercritical tidal plume front occurs with southeasterly winds prevailing in spring tide due to the strong advection in the tidal plume the tidal salt deficit flux can reach as high as 12 5 of the mean current flux and illustrates the combined forcing of tide and wind key points the paper clarifies the pearl river plume anatomy under two typical winds spring tide facilitates the supercritical pearl river tidal plume front tide determines tidal salt deficit flux strength wind determines the direction

effects of tides on freshwater and volume transports in the changjiang river plume 1 effects of tides on the changjiang river plume are investigated using a numerical model of the east china and yellow seas in the absence of tides the buoyancy driven coastal current downstream of the river mouth is a surface trapped plume attached to the coast in the presence of tides however the plume shifts away from the coast and features a bottom boundary layer the freshwater transport by the coastal current accounts for only 35 of the changjiang river discharge without tides but increases to 80 with tides tidal currents stabilize the plume bulge near the river mouth and force the plume water to move in the direction of tidal currents thus increasing the downstream freshwater transport in contrast tidal residual currents are weak and make little contributions to the total freshwater transport tidal mixing reduces the plume s buoyancy but increases its thickness so that the freshwater transport is insensitive to the strength of turbulent mixing volume transport in the tidal affected buoyancy coastal current exceeds the river discharge by 4 to 12 times as opposed to 2 3 fold amplification in the plume without tides tidal mixing between the plume and ambient shelf waters produces higher salinity classes in the plume so that the volume flux in the downstream coastal current increases to discharge the freshwater released from the changjiang river

partial collapse of the marine carbon pump after the cretaceous paleogene boundary the impact of an asteroid at the end of the cretaceous caused mass extinctions in the oceans a rapid collapse in surface to deepocean carbon isotope gradients suggests that transfer of organic matter to the deep sea via the biological pump was severely perturbed however this view has been challenged by the survival of deep sea benthic organisms dependent on surface derived food and uncertainties regarding isotopic fractionation in planktic foraminifera used as tracers here we present new stable carbon d 13 c and oxygen d 18 o isotope data measured on carefully selected planktic and benthic foraminifera from an orbitally dated deep sea sequence in the southeast atlantic our approach uniquely combines d 18 o evidence for habitat depth of foraminiferal tracer species with species specific d 13 c eco adjustments and compares isotopic patterns with corresponding benthic assemblage data our results show that changes in ocean circulation and foraminiferal vital effects contribute to but cannot explain all of the observed collapse in surface to deep ocean foraminiferal d 13 c

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

summer monsoon induced upwelling dominated coastal sea surface temperature variations in the northern south china sea over the last two millennia the south china sea scs situated to the north of the indo pacific warm pool ipwp is under the strong influence of the asian monsoon system however coastal sea surface temperature sst reco

coalification history of the stephanian cinera matallana pull apart basin nw spain combining anisotropy of vitrinite reflectance and thermal modelling the stephanian cinera matallana basin of nw spain comprises 1 500 m of alluvial to lacustrine coal bearing sediments which were deposited in a late variscan transtensional transpressional pull apart setting the relationship between coalification pattern and rock deformation was evaluated by measurements of the anisotropy of vitrinite reflectance avr the avr ellipsoids reveal both pre tectonic elements related to the bedding fabric and syn tectonic elements related to folding producing biaxial ellipsoid shapes with the maximum reflectance parallel to fold axes the mean coalification gradient for the stephanian succession is about 0 62 rr km calculations of the mean palaeo geothermal gradient are presented on the basis of three different empirical equations a palaeo geothermal gradient of 85 c km is considered the most realistic with an overburden of about 1 000 m 1 d numerical modelling of the burial history results in two possible scenarios the most preferable involving a palaeo heat flow of 150 mw m2 and an overburden of ca 1 050 m these results indicate that maximum coalification was related to a localised but high palaeo heat flow geothermal gradient the anisotropy of vitrinite reflectance highlights the interactive and transitional nature of sedimentary compaction and rock deformation on the maturation of organic material within strike slip fault zones