equatorward pathways of solomon sea water masses and their modifications the solomon sea is a key region of the southwest pacific ocean connecting the thermocline subtropics to the equator via western boundary currents wbcs modifications to water masses are thought to occur in this region because of the significant mixing induced by internal tides eddies and the wbcs despite their potential influence on the equatorial pacific thermocline temperature and salinity and their related impact on the low frequency modulation of el nino southern oscillation modifications to water masses in the solomon sea have never been analyzed to our knowledge a high resolution model incorporating a tidal mixing parameterization was implemented to depict and analyze water mass modifications and the solomon sea pathways to the equator in a lagrangian quantitative framework the main routes from the solomon sea to the equatorial pacific occur through the vitiaz and solomon straits in the thermocline and intermediate layers and mainly originate from the solomon sea south inflow and from the solomon strait itself water mass modifications in the model are characterized by a reduction of the vertical temperature and salinity gradients over the water column the high salinity of upper thermocline water subtropical mode water stmw is eroded and exported toward surface and deeper layers whereas a downward heat transfer occurs over the water column consequently the thermocline water temperature is cooled by 0 15 0 3 c from the solomon sea inflows to the equatorward outflows this temperature modification could weaken the stmw anomalies advected by the subtropical cell and thereby diminish the potential influence of these anomalies on the tropical climate the solomon sea water mass modifications can be partially explained 60 by strong diapycnal mixing in the solomon sea as for stmw about a third of this mixing is due to tidal mixing

surface circulation in the solomon sea derived from lagrangian drifter observations abstractvelocity measurements from satellite tracked surface drifters collected between 1994 and 2010 are used to map the surface circulation in the solomon sea the last passageway for waters of subtropical origin flowing northward toward the equator where they replenish the pacific warm pool pseudo eulerian statistics of the drifter observations show a strong seasonal cycle in both the mean circulation and the eddy kinetic energy in the region the circulation is characterized by a strong northward flow from june to november the season of strong southeasterly trade winds over the solomon sea and a mostly southward flow with increased variability from december to may when the winds over the sea are weak the seasonal velocity signal has the largest magnitude narrowly along the double western boundary formed by the eastern coastlines of new guinea and the solomon islands suggesting that direct wind driving with its much larger spatial scales is not the main influence in addition the surface circu

reconstruction of the fire history in the siedlungskammer burgweinting bavaria germany in relation to settlement and environmental history palaeoenvironmental investigations were carried out in the siedlungskammer prehistoric settlement area burgweinting regensburg bavaria germany to reveal past settlement conditions and human impact on the environment two sequences were obtained from the islinger muhlbach fen in close proximity to the archaeological excavation site in burgweinting which documents an almost continuous settlement history since the neolithic period the analyses of the sequences comprise stratigraphic geochemical and microscopic charcoal analyses for chronological information radiocarbon dating was conducted on a total of 10 samples thus the first long term fire record was reconstructed for the investigation area and the results were correlated based on radiocarbon dating with the available environmental information and settlement history in the siedlungskammer burgweinting the fire record reveals an almost continuous but alternating fire history furthermore it shows that fire played an important role in the siedlungskammer burgweinting and that most probably as early as the mesolithic hunterer gatherers deliberately used fire

the southwest pacific ocean circulation and climate experiment spice the southwest pacific ocean circulation and climate experiment spice is an international research program under the auspices of clivar the key objectives are to understand the southwest pacific ocean circulation and the south pacific convergence zone spcz dynamics as well as their influence on regional and basin scale climate patterns south pacific thermocline waters are transported in the westward flowing south equatorial current sec toward australia and papua new guinea on its way the sec encounters the numerous islands and straits of the southwest pacific and forms boundary currents and jets that eventually redistribute water to the equator and high latitudes the transit in the coral solomon and tasman seas is of great importance to the climate system because changes in either the temperature or the amount of water arriving at the equator have the capability to modulate the el nino southern oscillation while the southward transports influence the climate and biodiversity in the tasman sea after 7 years of substantial in situ oceanic observational and modeling efforts our understanding of the region has much improved we have a refined description of the spcz behavior boundary currents pathways and water mass transformation including the previously undocumented solomon sea the transports are large and vary substantially in a counter intuitive way with asymmetries and gating effects that depend on time scales this paper provides a review of recent advancements and discusses our current knowledge gaps and important emerging research directions

the origin of the pacific equatorial 13 c water abstract examination of the vertical distributions of temperature salinity oxygen and nutrient salts in the thermostad of the equatorial 13 c water in the eastern pacific ocean indicates that local vertical mixing is unimportant in creating the thermostad and the characteristics of the 13 c water maps are presented that show the oceanwide distributions of depth geostrophic flow salinity oxygen phosphate silica and nitrate on the 160 cl t 1 isanosteric surface which nearly coincides with the core of the 13 c water the maps suggest that the original characteristics of the 13 c water are acquired in the surface and thermocline layers to the northeast of new zealand and in the tasman sea by winter convection and vertical mixing the acquired characteristics are advected to the thermostad in the eastern pacific via a long route starting from the source region the flow is first eastward in high latitudes and then returns westward in low latitudes around the anticyclonic subtropical gyre of the sout

iron age wood usage at an enclosure in northern germany the first known iron age enclosure in the northern german state of schleswig holstein was discovered in 2010 archaeological excavation revealed a trench a palisade and an occupation layer the function of the wall and trench system remains unknown but there are several possibilities it could have been used for protection as a type of symbolic separation or to demarcate a cult site the enclosure was constructed around the year zero charcoal samples were taken in a spatially detailed manner during excavation as well as a new pollen core from a small spring mire directly next to the site anthracological analysis showed that quercus oak was the main type of wood used in the construction of this enclosure thirteen additional wood taxa were identified of which the next best represented is corylus hazel and surprisingly a significant amount of ilex holly was found the samples did not contain fagus beech or carpinus hornbeam which are both common in the area today according to pollen data fagus had begun to establish in the local woodland during the time of the enclosure but did not gain importance before the migration period by diameter analysis of the charcoals the size of the used wood branch or trunk was reconstructed in addition mean annual tree ring widths of the used wood especially quercus show that the wood comes from young stems and or branches of older trees and probably not from coppiced wood the study shows that even small scale archaeological excavations can yield important new data on wood utilization with a high spatial precision which contributes to the reconstruction of local woodland composition

interdisciplinary characterisation and environmental imprints of mining and forestry in the upper durance valley france during the holocene the upper durance valley contains the largest silverelead mines of the french southern alps we investigated the characterisation and impact of these mining activities and associated forestry in the argentiere l argentiere la bessee and faravel freissinieres districts using a multidisciplinary approach that includes archaeological palynological geochemical anthracological and dendrochrono logical studies applied to mining remnants and a peat bog fangeas in the faravel district more specifically we studied the occurrence of lead contamination episodes the chronology of mining activities and their link to the evolution in woodland cover our chronology is based on mining archaeology radiocarbon dating of about thirty charcoal samples and the dendrochronological analysis of more than 170 specimens of exhumed waterlogged wood the anthracological analysis was established with more than 10 000 charcoals from firesetting the main geochemical approach was based on the analysis of lead and its stable isotopes in sediment fractions from a peat core the combination of palynological records and lead isotope imprints were used to characterise i a roman contamination episode unknown to archaeology ii the development of medieval mining activities and iii the reactivation of mining during the modern period and the industrial revolution medieval mining coincides with an extension of the high mountain agropastoral areas the in situ continuous human activities in the same industrial territory led to rational communal management of subalpine forests but also to their parcelling that reached its peak in the high middle ages mining during the modern period coincides with significant stress on woodland areas that also appears to be related to lumber and fuel timber production for shipyards french royal navy as well as the functioning of several military fortresses the mining reactivation during the 19th c matched public measures of forest protection that took shape in the afforestation programme of the uplands

oceanic transports through the solomon sea the bend of the new guinea coastal undercurrent 1 thermocline waters of the tropical southwest pacific can be traced back to the center of the south pacific basin and have a potential influence on equatorial surface conditions and on the characteristics of the el nino southern oscillation on decadal timescales the solomon sea is traversed by this influential flow and therefore is an optimal place for exploring this oceanic connection to the equator from a high resolution hydrographic survey at which we applied an inverse box model we describe the main pathways at the entrance of the solomon sea and more particularly the extremely sharp bend of the western boundary current around the south east tip of papua new guinea of the 30 sv subtropical waters transported into the coral sea from the east above 1300 m 29 5 sv makes its way through the solomon sea with a large part transported in a boundary current at the entrance of the solomon sea around the south east tip of papua new guinea the gulf of papua current turns abruptly to the north in a very sharp bend as it merges into the new guinea coastal undercurrent on its way toward the equator the warm currents transport large amounts of internal energy with a total of 1 0 0 3 1015w entering the solomon sea from the south

intermediate zonal jets in the tropical pacific ocean observed by argo floats abstractargo float data in the tropical pacific ocean during january 2003 august 2011 are analyzed to obtain lagrangian subsurface velocities at their parking depths maps of mean zonal velocities at 1000 and 1500 m are presented at both depths a series of alternating westward and eastward zonal jets with a meridional scale of 1 5 is seen at the basin scale from 10 s to 10 n these alternating jets with mean speeds about 5 cm s 1 are clearly present in the western and central parts of the basin but weaken and disappear approaching the eastern coast they are stronger in the southern hemisphere along the equator at both 1000 and 1500 m a westward jet is seen the jets closer to the equator are remarkably zonally coherent across the basin but the jets farther poleward appear broken in several segments in the western half of the basin the 1000 m zonal jets appear to slant slightly poleward from east to west at the western boundary in the south east of solomon islands and papua new guinea the al

fuel origin and firing product preservation in archaeological occupation contexts abstract we intend here to examine the range of factors involved in the preservation at short to long term of firing byproducts with respect to the nature of combustion processes and the fuel origin our objective is to refresh the cultural and palaeoenvironmental relevance of combustion deposits the study is based on the comparison of two recent situations of natural fires and a selection of well preserved firing records from rockshelters and caves in diverse geographical and cultural contexts the recent analogues comprise a two year investigation of the 2012 july large forest fire at alt emporda northern cataluna spain and a study of the 2014 lightning struck pine tree allanche cantal france in situ characterization at micro to nanoscale of firing products has been performed using the sem eds in backscatter mode on individual grains and composite aggregates which were extracted by gentle water sieving from combustion microstrata and firing products meticulously sampled in the field the survey of the alt emporda firing record confirms the rapid loss of intact ashes and heating scars leaving after two years a regenerated soil without any obvious evidence of this fire except for scattered charcoal the study of allanche lightning struck pine tree shows that lightning produces a suite of robust components diagnostic of flash heating and plasma assisted combustion polymer filaments vitreous char metal coatings and singular minerals their durability expresses the refractory and hydrophobic properties of materials formed by transient heating and plasma processes the identification of similar robust components in all the firing products of the archaeological contexts tested here shows that plasma assisted combustion and flash heating exert a major role on the durability of firing records the archaeological combustion contexts are separated into two types of intact firing records 1 the ones with abundant mineralised charcoal vitreous char and metal coatings would trace the use of fuel acquired from wood affected by a lightning strike 2 the thick white ash with polymer films refractory minerals and metal coatings would indicate wood fuel collected during periods of active aeroplasma processes in the atmosphere due to increased dust loading and intense ionization the study is suggested to offer a challenging perspective to elucidate further the role that lightning and plasma processes exerted on ancestral pyrotechnology by occasionally providing wood fuel resources of long durability low degradability and high calorific power

the annual cycle of circulation of the southwest subtropical pacific analyzed in an ocean gcm abstract an ocean gcm interpreted in light of linear models and sparse observations is used to diagnose the dynamics of the annual cycle of circulation in the western boundary current system of the southwest pacific ocean the simple structure of annual wind stress curl over the south pacific produces a large region of uniformly phased stationary thermocline depth anomalies such that the western subtropical gyre spins up and down during the year directing flow anomalies alternately toward and away from the boundary at its northern end near 10 s the response of the western boundary currents is to redistribute these anomalies northward toward the equator and southward to the subtropical gyre a redistribution that is determined principally by linear rossby processes not boundary dynamics when the subtropical gyre and south equatorial current sec are strong in the second half of the year the result is both increased equatorward transport of the new guinea coastal current and poleward transport a

complementary use of glider data altimetry and model for exploring mesoscale eddies in the tropical pacific solomon sea mesoscale activity is an important component of the solomon sea circulation that interacts with the energetic low latitude western boundary currents of the south tropical pacific ocean carrying waters of subtropical origin before joining the equatorial pacific mixing associated with mesoscale activity could explain water mass transformation observed in the solomon sea that likely impacts el nino southern oscillation dynamics this study makes synergetic use of glider data altimetry and high resolution model for exploring mesoscale eddies especially their vertical structures and their role on the solomon sea circulation the description of individual eddies observed by altimetry and gliders provides the first elements to characterize the 3d structure of these tropical eddies and confirms the usefulness of the model to access a more universal view of such eddies mesoscale eddies appear to have a vertical extension limited to the surface waters sw and the upper thermocline water utw i e the first 140 150 m depth most of the eddies are nonlinear meaning that eddies can trap and transport water properties but they weakly interact with the deep new guinea coastal undercurrent that is a key piece of the equatorial circulation anticylonic eddies are particularly efficient to advect salty and warm sw coming from the intrusion of equatorial pacific waters at solomon strait and to impact the characteristics of the new guinea coastal current cyclonic eddies are particularly efficient to transport south pacific tropical water sptw anomalies from the north vanuatu jet and to erode by diapycnal mixing the high sptw salinity

exploring the mesoscale activity in the solomon sea a complementary approach with a numerical model and altimetric data the solomon sea is an area of high level of eddy kinetic energy eke and represents a transit area for the low latitude western boundary currents llwbcs connecting the subtropics to the equatorial pacific and playing a major role in enso dynamics this study aims at documenting the surface mesoscale activity in the solomon sea for the first time our analysis is based on the joint analysis of altimetric data and outputs from a 1 12 model simulation the highest surface eke is observed in the northern part of the basin and extends southward to the central basin an eddy tracking algorithm is used to document the characteristics and trajectories of coherent mesoscale vortices cyclonic eddies generated in the south basin are advected to the north by the llwbcs before merging with stationary mesoscale structures present in the mean circulation anticyclonic eddies are less numerous they are generated in the southeastern basin propagate westward reach the llwbcs and dissipate the seasonal and interannual modulations of the mesoscale activity are well marked at seasonal time scale maximum minimum activity is in may june september at interannual time scale the mesoscale activity is particularly enhanced during la nina conditions if instabilities of the regional circulations seem to explain the generation of mesoscale features the modulation of the mesoscale activity seems to be rather related with the intrusion at solomon strait of the surface south equatorial current rather than to the llwbcs by modulating the horizontal and vertical shears suitable for instabilities

plant landscape reconstruction above the current timberline at the monte cimone and corno alle scale mountain areas northern apennines italy during the late holocene the evidence from soil charcoal this paper presents the first pedoanthracological study carried out on two mountains of the northern apennines monte cimone and corno alle scale where the results provided new palaeoenvironmenta

interpreting palaeofire evidence from fluvial sediments a case study from santa rosa island california with implications for the younger dryas impact hypothesis fluvial sequences from the late pleistocene to the holocene are exposed in arlington canyon santa rosa island northern channel islands california usa including one outcrop that features centrally in the controversial hypothesis of an extra terrestrial impact at the onset of the younger dryas the fluvial sequence in arlington canyon contains a significant quantity and range of organic material much of which has been charred the purpose of this study was to systematically describe the key outcrop of the arlington sequence provide new radiocarbon age control and analyse organic material in the arlington sediments within a rigorous palaeobotanical and palaeo charcoal context these analyses provide a test of previous claims for catastrophic impact induced fire in arlington canyon carbonaceous spherular materials were identified as predominantly fungal sclerotia carbon elongates are predominantly arthropod coprolites including termite frass glassy carbon formed from the precipitation of tars during charcoalification none of these materials indicate high temperature formation or combustion charcoal and other materials in arlington canyon document widespread and frequent fires both before and after the onset of the younger dryas recording predominantly low temperature surface fires in summary we find no evidence in arlington canyon for an extra terrestrial impact or catastrophic impact induced fire

x ray microtomographic imaging of charcoal we assess the potential of x ray microtomography as a tool for the non destructive three dimensional examination of the internal structure of charcoal microtomographic analysis of a series of charcoals produced by the experimental pyrolysis of pine wood at temperatures from 300 and 600 c in nitrogen only and in nitrogen mixed with 2 oxygen indicates that despite substantial shrinkage observed porosity pore size and pore connectivity are all increased by pyrolysis and also by chemical oxidation analysis of a number of altered and unaltered archaeological and geological charcoals has demonstrated the capacity of the technique to identify and map the distribution of authigenic mineral contamination within charcoal fragments the results are of significance to radiocarbon dating in that they provide insights into the mechanisms by which charcoal can be contaminated by extraneous carbon in the natural environment

an eddy permitting model of the atlantic circulation evaluating open boundary conditions as part of the french clipper project an eddy permitting model of the atlantic circulation has been run for 22 years the domain has open boundaries at drake passage and at 30 e from africa to antarctica the simulated mean circulation as well as the eddy activity is satisfactory for a 1 3 model resolution and the meridional heat transport at 30 s is within the range estimated from observations we use the mixed open boundary algorithm of barnier et al 1998 which has both a radiation condition and a relaxation to climatology the climatological boundary forcing strongly constrains the solution in the whole domain the model heat balance adjusts through the surface heat flux retroaction term more than the open boundaries the radiation phase velocities calculated within the algorithm are analyzed this shows quite surprisingly that both the eastern and western boundaries have a similar behavior regardless of the preferred directions for advection mainly eastward and wave propagation mainly westward our results confirm that open boundary algorithms behave differently according to the dynamics of the region considered the passive boundary condition that penduff et al 2000 applied successfully in the north eastern atlantic does not work in the present south atlantic model we emphasize the need for a careful prescription of the climatology at the open boundary for which a new approach based on synoptic sections is implemented

anthracology and taphonomy from wood gathering to charcoal analysis a review of the taphonomic processes modifying charcoal assemblages in archaeological contexts abstract a discussion on the representativeness of charcoal from archaeological contexts and their potential for palaeoecological reconstruction is presented the charcoal deposits studied are the result of human activities and natural processes difficult to separate on the basis of their effects only this is why taphonomy should not be limited to the study of charcoal after the extinction of fire as a result our questioning has been widened to include the entire succession of processes from past vegetation to the anthracological diagram we propose a review of the taphonomic processes affecting anthracological assemblages in archaeological contexts from wood gathering to the analysis of charcoal results human practices appear clearly as the first filter determining or conditioning the assemblage the combustion process can induce a double filter by limiting the taxonomic information and by falsifying the initial quantity of burned wood post depositional agents represent a third level of filters between the vegetation and the anthracological assemblage finally sampling and quantification methods can also induce a distortion of the assemblage the aim of this paper is to present the state of the discipline today the problems already solved and the questions that remain to be studied

impact of carbonization on growth rings dating by dendrochronology experiments on oak charcoals collected from archaeological sites abstract to understand the impact of carbonization on the acquisition of dendrochronological dating several experiments were conducted the shrinkage of ring widths from woods measured before and after carbonization was first characterized to determine whether the dendrochronological signal was affected by carbonization joists from a 16th century building were dated both before and after carbonization case studies on archaeological charcoals were also carried out using a protocol developed to enhance the visibility of growth rings the fragmentation inherent to charcoal required in some cases a more complex approach to reconstruct the growth of charred wood from the pith to the periphery these experiments were used to characterize the dating potential of dendrochronology based on charcoals from archaeological excavations

human settlement and vegetation climate relationships in the greenland stadial 5 at the piovesello site northern apennines italy the gravettian settlements of europe are considered as an expression of human adaptation to harsh climates in southern europe however favorable vegetation climate conditions supported hunters gatherer subsistence and the maintenance of their large scale networks this was also the case of the north adriatic plain and the apennine mountain ridge in italy traditionally considered lacking evidence the northern part of the apennine ridge has recently yielded the early gravettian site of piovesello located at 870 m a s l survey and excavation revealed lithic artifacts in primary position embedded in loamy sediments radiocarbon dating anthracological and extended palynological and microcharcoal analyses have been integrated to reconstruct the palaeoecological context of this camp which was probably positioned above the timberline in an arid rocky landscape bounding the fronts of local glaciers close to their maximum expansion at the time of greenland stadial gs 5 32 04 28 9 ka cal bp human activity left ephemeral traces represented by lithic artefacts charcoal and the introduction of radiolarites from sources in proximity to the site and of chert from very far western sources evidence from piovesello contributes to the reconstruction of human and vegetation ecology during late pleistocene glaciations and also provides hints for the historical biogeography of petrophytic plants and their orographic relics in the northern apennine

wood uses at el mirador cave atapuerca burgos based on anthracology and dendrology abstract el mirador cave contains a continuous sedimentary deposit of burnt sediments identified as fumier layers corresponding to burnt sheep and goat dung this sediment infilling has yielded a large number of charcoal remains the general objective of this study is to contribute to the knowledge of western mediterranean holocene vegetation and land use history by combining classical wood charcoal analysis with dendrological charcoal studies a specific aim of this work is to characterize the origin of the anthracological assemblage anthracological analyses show a continuous sequence dominated by oaks in which deciduous oaks exhibit higher values during the early neolithic with an increase in evergreen oaks from the middle neolithic onwards the anthracological data suggests that human activities and climatic variations throughout the holocene caused changes in the forests the dendrology results on a small quercus sp deciduous sample suggests that the wood used corresponds to young branches bearing tree rings with a rapid growth rate which might indicate that the trees were regularly shredded both approaches suggest that oak was probably used as leafy fodder and its remains were burnt during repeated combustion processes

a new bathymetry of the northeast greenland continental shelf constraints on glacial and other processes a new digital bathymetric model dbm for the northeast greenland neg continental shelf 74 n 81 n is presented the dbm has a grid cell size of 250 m 250 m and incorporates bathymetric data from 30 multibeam cruises more than 20 single beam cruises and first reflector depths from industrial seismic lines the new dbm substantially improves the bathymetry compared to older models the dbm not only allows a better delineation of previously known seafloor morphology but in addition reveals the presence of previously unmapped morphological features including glacially derived troughs fjords grounding zone wedges and lateral moraines these submarine landforms are used to infer the past extent and ice flow dynamics of the greenland ice sheet during the last full glacial period of the quaternary and subsequent ice retreat across the continental shelf the dbm reveals cross shelf bathymetric troughs that may enable the inflow of warm atlantic water masses across the shelf driving enhanced basal melting of the marine terminating outlet glaciers draining the ice sheet to the coast in northeast greenland knolls sinks and hummocky seafloor on the middle shelf are also suggested to be related to salt diapirism north south orientated elongate depressions are identified that probably relate to ice marginal processes in combination with erosion caused by the east greenland current a single guyot like peak has been discovered and is interpreted to have been produced during a volcanic event approximately 55 ma ago

late holocene history of woodland dynamics and wood use in an ancient mining area of the pyrenees ariege france this paper focuses on past woodland changes and land uses in an ancient mining area of the eastern pyrenees ari ege france the area discussed is located at the western entrance of the vicdessos a valley with significant steel production and it is crossed by the road used from the 14th c to the end of the 18th c for the iron charcoal exchange with the forest province of couserans the introduction of this singular exchange and the silver ore mining history of this border area raise the question of their impact on forest cover changes and changes in human practices and their link with anthropisation processes to deal with this issue we put in place an interdisciplinary approach involving archaeology charcoal analysis ecological history and geochemistry the archaeological investigations and fourteen radiocarbon ages allowed characterising and dating of mining and charcoal making remains they situate the emergence of metal ore mining during the second iron age and charcoal making activity between the 15th and 17th c the geochemical analysis of 9 galena samples showed some different isotopic signatures between ores extracted in ancient times and those mined during the modern period the charcoal analysis of i 2442 charcoals from 31 charcoal kilns ii 500 from one pedoarchaeological pit excavated in a waste heap related to firesetting and iii 250 from two pedoanthracological sampling points carried out in the charcoal burning forest permits a detailed reconstruction of the woodland cover changes from the second iron age to the 19th c furthermore the combination of data from different disciplines allows for a long term reconstruction of human practices history and woodland management for different uses in particular the results show the transformation of the fir beech forest still dominated by fir around the turn of the roman era into pure beech wood managed on northern slopes for human daily needs occasionally mining lumber and mainly charcoal production until the 19th c the elimination of fir dates back to the 17th c this assumes the end of lumber activities in that period pedoanthracological and palynological data suggest that southern slopes progressively deforested since the bronze age were entirely devoted to permanent agropastoral activities probably at least since the end of the medieval period

the international bathymetric chart of the southern ocean ibcso version 1 0 a new bathymetric compilation covering circum antarctic waters the international bathymetric chart of the southern ocean ibcso version 1 0 is a new digital bathymetric model dbm portraying the seafloor of the circum antarctic waters south of 60 degrees s

mesoscale to submesoscale transition in the california current system part i flow structure eddy flux and observational tests in computational simulations of an idealized subtropical eastern boundary upwelling current system similar to the california current a submesoscale transition occurs in the eddy variability as the horizontal grid scale is reduced to o 1 km this first paper in a series of three describes the transition in terms of the emergent flow structure and the associated time averaged eddy fluxes in addition to the mesoscale eddies that arise from a primary instability of the alongshore wind driven currents significant energy is transferred into submesoscale fronts and vortices in the upper ocean the submesoscale arises through surface frontogenesis growing off upwelled cold filaments that are pulled offshore and strained in between the mesoscale eddy centers in turn some submesoscale fronts become unstable and develop submesoscale meanders and fragment into roll up vortices associated with this phenomenon are a large vertical vorticity and rossby number a large vertical velocity relatively flat horizontal spectra contrary to the prevailing view of mesoscale dynamics a large vertical buoyancy flux acting to restratify the upper ocean a submesoscale energy conversion from potential to kinetic a significant spatial and temporal intermittency in the upper ocean and material exchanges between the surface boundary layer and pycnocline comparison with available observations indicates that submesoscale fronts and instabilities occur widely in the upper ocean with characteristics similar to the simulations

the effect of subtropical cooling on the amplitude of enso a numerical study the effect of an enhanced subtropical surface cooling on el nino southern oscillation enso through the ocean tunnel is investigated using a coupled model here the term ocean tunnel refers to the water pathway that connects the equatorial upwelling water to the subtropical extratropical surface water the subtropical cooling is introduced through a reduction of the radiative convective equilibrium sst sstp in that region the sstp for the equatorial region is kept fixed it is found that an enhanced cooling in the subtropics results in a regime with stronger enso this is because an enhanced subtropical cooling reduces the temperature of the water feeding the equatorial undercurrent through the ocean tunnel the resulting larger difference between the warm pool sst and the temperature of the equatorial thermocline water the source water for the equatorial upwelling tends to increase the equatorial zonal sst contrast between the western and the eastern pacific in response to this destabilizing forcing to the coupled equatorial ocean atmosphere a stronger enso develops enso is found to regulate the time mean difference between the warm pool sst and the temperature of the equatorial undercurrent the findings provide further support for the heat pump hypothesis for enso which states that enso is an instability driven by the meridional differential heating over the pacific ocean and that enso regulates the long term stability of the coupled equatorial pacific climate the results also substantiate the notion that surface variability from higher latitudes may influence equatorial sst variability through the ocean tunnel

enso and short term variability of the south equatorial current entering the coral sea abstracthistorical section data extending to 1985 are used to estimate the interannual variability of transport entering the coral sea between new caledonia and the solomon islands typical magnitudes of this variability are 5 8 sv sv 106 m3 s 1 in the 0 400 m layer relative to 400 m and 8 12 sv in the 0 2000 m layer relative to 2000 m on a mean of close to 30 sv relative to 2000 m transport increases a few months after an el nino event and decreases following a la nina interannual transport variability is well simulated by a reduced gravity long rossby wave model vigorous westward propagating mesoscale eddies can yield substantial aliasing on individual ship or glider surveys since transport variability is surface intensified and well correlated with satellite derived surface geostrophic currents a simple index of south equatorial current transport based on satellite altimetry is developed

ssh wavenumber spectra in the north pacific from a high resolution realistic simulation abstractfollowing recent studies based on altimetric data this paper analyses the spectral characteristics of the sea surface height ssh using a new realistic simulation of the north pacific ocean with high resolution in the horizontal and 100 vertical levels this simulation resolves smaller scales down to 10 km than altimetric data limited to 70 km because of the noise level in high eddy kinetic energy eke regions as in the western part ssh spectral slope almost follows a k 4 with k the wavenumber or slightly steeper law in agreement with altimeter studies the new result is that unlike altimeter studies such a k 4 slope is also observed in low eke regions as in the eastern part in these regions this slope mostly concerns scales not well resolved by altimetric data such k 4 ssh spectral slopes are weaker from what is expected from quasigeostrophic turbulence theory but closer to surface quasigeostrophic sqg turbulence theory the consequence is that the small scales concerned

do altimeter wavenumber spectra agree with the interior or surface quasigeostrophic theory in high eddy energy regions it is generally assumed that sea level wavenumber spectra compare well with quasigeostrophic qg turbulence models and that spectral slopes are close to the expected k 5 law this issue is revisited here sea level wavenumber spectra in the gulf stream kuroshio and agulhas regions are estimated using the most recent altimeter datasets the ocean topography experiment topex poseidon jason 1 the environmental satellite envisat and the geosat follow on the authors show that spectral slopes in the mesoscale band are significantly different from a k 5 law in disagreement with the qg turbulence theory however they very closely follow a k 11 3 slope which indicates that the surface quasigeostrophic theory sqg is a much better dynamical framework than the qg turbulence theory to describe the ocean surface dynamics because of the specific properties of the sqg theory these results offer new perspectives for the analysis and interpretation of satellite data

a stability analysis of tropical ocean atmosphere interactions bridging measurements and theory for el nino abstract interactions between the tropical oceans and atmosphere permit a spectrum of natural modes of oscillation whose properties period intensity spatial structure and direction of propagation depend on the background climatic state i e the mean state this mean state can be described by parameters that include the following the time averaged intensity of the pacific trade winds the mean depth h of the thermocline and the temperature difference across the thermocline t a stability analysis by means of a simple coupled ocean atmosphere model indicates two distinct families of unstable modes one has long periods of several years involves sea surface temperature variations determined by vertical movements of the thermocline that are part of the adjustment of the ocean basin to the fluctuating winds requires a relatively deep thermocline and corresponds to the delayed oscillator the other family requires a shallow thermocline has short periods of a year or two has sea surface tempe

seasonal modulations in the eddy field of the south pacific ocean abstract decade long satellite altimeter data from the ocean topography experiment topex poseidon and european remote sensing satellite 1 and 2 ers 1 2 missions are analyzed to investigate the eddy signals in the south pacific ocean high eddy kinetic energy eke bands with well defined annual cycles are detected along the eastward flowing surface currents of the south tropical countercurrent stcc between 21 29 s and the south equatorial countercurrent secc centered near 9 s overriding the westward flowing south equatorial current sec the stcc layer has the sign of its mean potential vorticity gradient opposite to that in the sec layer subjecting the vertically sheared stcc sec system to baroclinic instability in austral winter the stcc sec system is baroclinically more unstable than in other seasons because of the large vertical shear and weak stratification this seasonal variation in the intensity of baroclinic instability is responsible for the seasonal modulation of the stcc s eke fi

multiscale dynamical analysis of a high resolution numerical model simulation of the solomon sea circulation a high 1 36 resolution numerical model is used to study the ocean circulation in the solomon sea an evaluation of the model with the few available observation shows that the 1 36 resolution model realistically simulates the solomon sea circulations the model notably reproduces the high levels of mesoscale eddy activity observed in the solomon sea with regard to previous simulations at 1 12 resolution the average eddy kinetic energy levels are increased by up to 30 40 in the present 1 36 simulation and the enhancement extends at depth at the surface the eddy kinetic energy level is maximum in march april may and is minimum in december january february the high subsurface variability is related to the variability of the western boundary current new guinea coastal undercurrent moreover the emergence of submesoscales is clearly apparent in the present simulations a spectral analysis is conducted in order to evidence and characterize the modeled submesoscale dynamics and to provide a spectral view of scales interactions the corresponding spectral slopes show a strong consistency with the surface quasi geostrophic turbulence theory

late pleistocene human occupation of the hyperarid core in the atacama desert northern chile abstract few archeological sites in south america contain uncontroversial evidence for when the first peopling of the continent occurred largely ignored in this debate extreme environments are assumed either as barriers to this early wave of migration or without potential for past habitability here we report on a rare 12 13 ka human occupation from quebrada mani site qm12 a plantless near rainless landscape 1240 m asl and 85 km from the pacific ocean located in the hyperarid core of the atacama desert this location harbored wetlands and riparian woodlands that were fed by increased rainfall further east in the central andes during the latest pleistocene excavations at qm12 yielded a diverse cultural assemblage of lithics burned and cut bones marine gastropods pigments plant fibers and wooden artifacts alongside a prepared fireplace sixteen radiocarbon dates from site qm12 on charcoal marine shells animal dung plant remains and wood reveal that the occupation took place between 12 8 and 11 7 ka these results demonstrate that the atacama desert was not a barrier to early american settlement and dispersal and provide new clues for understanding the cultural complexity and diversity of the peopling of south america during the last glacial interglacial transition

inferring dynamics from the wavenumber spectra of an eddying global ocean model with embedded tides 1 the slopes of the wavenumber spectra of sea surface height ssh and kinetic energy ke have been used to infer interior or surface quasi geostrophic qg or sqg dynamics of the ocean however inspection of spectral slopes for altimeter ssh in the mesoscale band of 70 to 250 km shows much flatter slopes than the qg or sqg predictions over most of the ocean comparison of altimeter wavenumber spectra with spectra from an eddy resolving global ocean circulation model the hybrid coordinate ocean model hycom at 1 12 5 equatorial resolution which has embedded tides suggests that the flatter slopes of the altimeter ssh may arise from three possible sources 1 presence of strong internal tides 2 shift of the inertial sub range to smaller scales and 3 altimeter noise artificially adding noise to the model tends to flatten the spectra for low ke regions near internal tide generating regions spectral slopes in the presence of internal waves are much flatter than qg or sqg predictions separating the variability into high and low frequency around periods of 2 days then a different pattern emerges with a flat high frequency wavenumber spectrum and a steeper low frequency wavenumber spectrum for low mesoscale ke the inertial sub range defined by the nearly flat enstrophy band moves to smaller scales and the mesoscale band of 70 to 250 km no longer represents the inertial sub range the model wavenumber spectra are consistent with qg and sqg theory when internal waves and inertial sub range shifts are taken into consideration

re evaluating the origins of late pleistocene fire areas on santa rosa island california usa abstract at the close of the pleistocene fire regimes in north america changed significantly in response to climate change megafaunal extinctions anthropogenic burning and possibly even an extraterrestrial impact on california s channel islands researchers have long debated the nature of late pleistocene fire areas discrete red zones in sedimentary deposits interpreted by some as prehistoric mammoth roasting pits created by humans further research found no evidence that these red zones were cultural in origin and two hypotheses were advanced to explain their origin natural fires and groundwater processes radiocarbon dating x ray diffraction analysis and identification of charcoal from six red zones on santa rosa island suggest that the studied features date between 27 500 and 11 400 cal yr bp and resulted from burning or heating not from groundwater processes our results show that fire was a component of late pleistocene channel island ecology prior to and after human colonization of the islands with no clear evidence for increased fire frequency coincident with paleoindian settlement extinction of pygmy mammoths or a proposed younger dryas impact event

gliders measure western boundary current transport from the south pacific to the equator abstract spray gliders most launched from small boats near shore have established a sustainable time series of equatorward transport through the solomon sea the first 3 5 years mid 2007 through 2010 are analyzed coast to coast equatorward transport through the solomon sea fluctuates around a value of 15 sv 1 sv 106 m3 s 1 with variations approaching 15 sv transport variability is well correlated with el nino indices like nino 3 4 with strong equatorward flow during one el nino and weak flow during two la ninas mean transport is centered in an undercurrent focused in the western boundary current variability has a two layer structure with layers separated near 250 m near the core of the undercurrent that fluctuate independently the largest variations are in midbasin confined to the upper layer and are well correlated with enso analysis of velocity and salinity on isopycnals shows that the western boundary current within the solomon sea consists of a deep core coming from the coral sea

charcoal analysis and dendrology data from archaeological sites in north western france during the last 15 years charcoal analysis of archaeological sites in north western france has been carried out in conjunction with systematic and detailed dendrological examination by considering these extrinsic criteria in association with the analytical results palaeo ethnographic and palaeo environmental information can be obtained the charcoals are classically identified under the microscope on the basis of their cellular structure this examination is associated with an observation of the ligneous structure on transverse sections using a binocular lens when charcoal fragments are large enough the growth ring widths are measured tree ring curvature is also noted finally alteration by fusion or radial cracks the presence of fungal hyphae and insect degradation are also recorded results are thus obtained on the nature of fuel used in domestic fireplaces and kilns the selection of timbers and their catchment areas are also revealed the average width of the growth rings in oak charcoal from domestic hearths coming from about forty sites in north western france shows a significant increase from 6000 to 2000 bp there is a similar increase in the number of heliophilic taxa used from the neolithic to the iron age this implies that the environment became more and more open because of use by society the interpretation of the dendrology results applied to charcoal analyses is obtained through a convergence of criteria thus charcoal analysis can provide more than just an identification of the species used and can yield fundamental information on the interaction of society with the environment

global variability of the wavenumber spectrum of oceanic mesoscale turbulence abstractthe wavenumber spectra of sea surface height from satellite altimeter observations have revealed complex spatial variability that cannot be explained by a universal theory of mesoscale turbulence near the edge of the core regions of high eddy energy agreement is observed with the prediction of the surface quasigeostrophic sqg turbulence theory which has fundamental differences from that of the traditional quasigeostrophic qg turbulence theory in the core regions of high eddy energy the spectra are consistent with frontogenesis that is not fully accounted for by the sqg theory however the observations in the vast ocean interior of low eddy energy exhibit substantial differences from the predictions of existing theories of oceanic mesoscale turbulence the spectra in these regions may reflect the ocean s response to short scale atmospheric forcing and air sea interaction the observations presented in this paper serve as a test bed for new theories and ocean general circulation models

burning wood or burning bone a reconsideration of flotation evidence from upper palaeolithic gravettian sites in the moravian corridor abstract this paper compares archaeobotanical and other data from new excavations at two upper palaeolithic sites dolni v stonice ii and p edmosti i in the moravian corridor czech republic both contain the traces of broadly contemporary gravettian occupations during the warmer episodes of the pleistocene which preceded the last glacial maximum yet their archaeobotanical remains show striking differences those from dolni v stonice ii being dominated by large quantities of conifer wood charcoal while those from p edmosti i are much more scanty and dominated by vitrified plant remains in association with large quantities of burnt bone we argue that these differences between these two datasets arise from different uses of fuel at either site bone at p edmosti i and wood at dolni v stonice ii subsequently we explore the possible reasons for this difference and argue that once likely taphonomic distinctions are accounted for these data on fuel use offer fresh insights into the functions and durations of these upper palaeolithic occupations of the moravian corridor and some possible implications for how archaeobotanical data from such sites should be interpreted

spatial patterns of mixing in the solomon sea the solomon sea is a marginal sea in the southwest pacific that connects subtropical and equatorial circulation constricting transport of south pacific subtropical mode water and antarctic intermediate water through its deep narrow channels marginal sea topography inhibits internal waves from propagating out and into the open ocean making these regions hot spots for energy dissipation and mixing data from two hydrographic cruises and from argo profiles are employed to indirectly infer mixing from observations for the first time in the solomon sea thorpe and finescale methods indirectly estimate the rate of dissipation of kinetic energy and indicate that it is maximum in the surface and thermocline layers and decreases by 2 3 orders of magnitude by 2000 m depth estimates of diapycnal diffusivity from the observations and a simple diffusive model agree in magnitude but have different depth structures likely reflecting the combined influence of both diapycnal mixing and isopycnal stirring spatial variability of is large spanning at least 2 orders of magnitude within isopycnal layers seasonal variability of reflects regional monsoonal changes in large scale oceanic and atmospheric conditions with increased in july and decreased in march finally tide power input and topographic roughness are well correlated with mean spatial patterns of mixing within intermediate and deep isopycnals but are not clearly correlated with thermocline mixing patterns

holocene vegetation changes in nw iberia revealed by anthracological and palynological records from a colluvial soil macroscopic charcoal pollen and non pollen palynomorphs were isolated from a colluvial soil located on a small hill in campo lameiro nw spain in order to elucidate the vegetation history of the area and its relation to fire and human activities the presence of macroscopic charcoal throughout the 2 10 m thick soil 42 samples is evidence of frequent fires during the last c 6300 years the charcoal record was dominated by quercus probably q robur ericaceae probably arbutus unedo and erica arborea and fabaceae mainly genista type abrupt changes in the charcoal assemblage are less explicit in the pollen sequence probably as a result of pollen inflow from the downhill surroundings of the study site combined results indicated that the original oak woodland was gradually replaced by pyrophytic shrubs ericaceae and fabaceae as a result of fire recurrence non pollen palynomorphs strongly suggested that vegetation was deliberately ignited by past human societies to facilitate grazing no evidence of local agricultural practices was found episodes of accel erated shrubland expansion occurred c 6000 5500 cal bp c 4000 3500 cal bp and c 1700 cal bp the latter of which caused the definitive settlement of shrublands dominated by ericaceae and fabaceae which are nowadays widespread in nw iberia

topographic and mixed layer submesoscale currents in the near surface southwestern tropical pacific abstractthe distribution and strength of submesoscale sm surface layer fronts and filaments generated through mixed layer baroclinic energy conversion and submesoscale coherent vortices scvs generated by topographic drag are analyzed in numerical simulations of the near surface southwestern pacific north of 16 s in the coral sea a strong seasonal cycle in the surface heat flux leads to a winter sm soup consisting of baroclinic mixed layer eddies mles fronts and filaments similar to those seen in other regions farther away from the equator however a strong wind stress seasonal cycle largely in sync with the surface heat flux cycle is also a source of sm processes sm restratification fluxes show distinctive signatures corresponding to both surface cooling and wind stress the winter peak in sm activity in the coral sea is not in phase with the summer dominance of the mesoscale eddy kinetic energy in the region implying that local surface layer forcing effects are more important for sm gene