developments in monitoring and modelling small scale river bed topography recent research in fluvial geomorphology has emphasized the spatially distributed feedbacks amongst river channel topography flow hydraulics and sediment transport although understanding of the behaviour of dynamic river channels has been increased markedly through detailed within channel process studies less attention has been given to the accurate monitoring and terrain modelling of river channel form using three dimensional measurements however such information is useful in two distinct senses firstly it is one of the necessary boundary conditions for a physically based deterministic modelling approach in which three dimensional topography and river discharge drive within channel flow hydraulics and ultimately spatial patterns of erosion and deposition and therefore channel change secondly research has shown that an alternative means of estimating the medium term bedload transport rate can be based upon monitoring spatial patterns of erosion and deposition within the river channel this paper presents a detailed assessment of the distributed monitoring and terrain modelling of river bed topography using a technique that combines rigorous analytical photogrammetry with rapid ground survey the availability of increasingly sophisticated terrain modelling packages developed for civil engineering application allows the representation of topographic information as a landform surface intercomparison of landform surfaces allows visualization and quantification of spatial patterns of erosion and deposition a detailed assessment is undertaken of the quality of the morphological information acquired this allow some general comments to be made concerning the use of more traditional methods to monitor and represent small scale river channel morphology

mediterranean planktonic foraminiferal faunas during the last glacial cycle this paper highlights the planktonic foraminiferal abundance variations during the last glacial cycle from six new cores along a roughly west east transect in the mediterranean sea together with results from previous studies multivariate statistical analysis describes a first significant axis that indicates a general sea surface temperature sst gradient from west to east as expected lower sst values are recorded in glacial times but the eastern and western basins seem to have reacted differently to glacial conditions the western basin shows a sst decrease from the alboran sea to the central mediterranean whereas the eastern basin records a west to east increase that is similar to the present day eastern mediterranean gradient these new results show that 1 few almost basin wide faunal trends may be recognised but these are interrupted by local anomalies with opposing trends and 2 major abundance variations are distinctly diachronous in some species and virtually synchronous in others the implication is that over the glacial interglacial timescale concerned biostratigraphy should only be used on a local rather than basin wide scale unless it is supported by other independent dating methods

middle to late holocene palaeoenvironmental study of gialova lagoon sw peloponnese greece abstract the coastal areas of eastern mediterranean have long been the subject of research due to their rapid geomorphological changes but also because of their archaeological interest our study is focused on a shallow coastal lagoon of peloponnese gialova lagoon which for several years has attracted the scientific interest of archaeologists geomorphologists as well as sedimentologists gialova lagoon is located near the ancient city of pylos the kingdom of king nestor during the mycenaean period 1600 1100 bc the objectives of this study are a to reconstruct the middle to late holocene depositional environments of the lagoon and b to correlate our data to already existing publications in order to shed new light on the holocene evolution of the lagoon and the associated coastal palaeoenvironmental changes an 8 m deep vibracore was drilled and a multi proxy analysis was carried out on the sediment sequence including sedimentological grain size analysis and moment measures total organic carbon toc total nitrogen tn and total phosphorus tp high resolution geochemical xrf scanning and palaeontological micro and macro faunal analysis the chronological framework is based on five 14c datings forming the basis for an age depth model calculated using the oxcal software the radiocarbon dates from previous studies 6 cores 20 dates were also taken into account the data synthesis and interpretation provided robust and coherent indications regarding the palaeoenvironment shoreline changes and the rate of geomorphological changes of the coastal area of gialova lagoon as well as useful information about the palaeonvironmental and palaeoclimatic conditions that prevailed during the mycenaean period the interpretation reveal a transition from a shallow marine environment 6500 5800 yr b p to a brackish lagoonal 5800 3300 yr b p followed by a shift towards a freshwater marsh environment 3300 yr b p to present

assessment of erosion and deposition in steep mountain basins by differencing sequential digital terrain models abstract digital elevation models dems built from repeated topographic surveys permit producing dem of difference dod that enables assessment of elevation variations and estimation of volumetric changes through time in the framework of sediment transport studies dem differencing enables quantitative and spatially distributed representation of erosion and deposition within the analyzed time window at both the channel reach and the catchment scale in this study two high resolution digital terrain models dtms derived from airborne lidar data 2 m resolution acquired in 2005 and 2011 were used to characterize the topographic variations caused by sediment erosion transport and deposition in two adjacent mountain basins gadria and strimm vinschgau venosta valley eastern alps italy these catchments were chosen for their contrasting morphology and because they feature different types and intensity of sediment transfer processes a method based on fuzzy logic which takes into account spatially variable dtms uncertainty was used to derive the dod of the study area volumes of erosion and deposition calculated from the dod were then compared with post event field surveys to test the consistency of two independent estimates results show an overall agreement between the estimates with differences due to the intrinsic approximations of the two approaches the consistency of dod with post event estimates encourages the integration of these two methods whose combined application may permit to overcome the intrinsic limitations of the two estimations the comparison between 2005 and 2011 dtms allowed to investigate the relationships between topographic changes and geomorphometric parameters expressing the role of topography on sediment erosion and deposition i e slope and contributing area and describing the morphology influenced by debris flows and fluvial processes i e curvature erosion and deposition relations in the slope area space display substantial differences between the gadria and the strimm basins while in the former erosion and deposition clusters are reasonably well discriminated in the latter characterized by a complex stepped structure we observe substantial overlapping erosion mostly occurred in areas that show persistency of concavity or transformation from convex and flat to concave surfaces whereas deposition prevailingly took place on convex morphologies less expected correspondences between curvature and topographic changes can be explained by the variable sediment transport processes which are often characterized by alternation of erosion and deposition between different events and even during the same event

living planktonic foraminifera in the eastern south atlantic during spring indicators of water masses upwelling and the congo zaire river plume abstract planktonic foraminifera were collected from pumped surface water samples and net tows over the upper 150 m of the water column in the eastern south atlantic ocean during october and november 1989 of the 24 recorded species 12 occur abundantly and form 6 foraminiferal assemblages the assemblages correlate with the physico chemical properties of the 6 vapor surface water masses the correlation of species with low salinity is due to properties co variant with salinity at several locations high concentrations of planktonic foraminifera were observed caused by frontal mixing or reproduction the g sacculifer g ruber white assemblage marks the south equatorial under current minor contribution of g menardii and n dutertrei to this assemblage reflects the subsurface equatorial under current the n dutertrei g siphonifera assemblage reflects the south equatorial counter current and equatorial under current the n pachyderma g bulloides assemblage reflects the coastal upwelling over the shelf and the filaments of mixed oceanic and upwelled water in the coastal of the benguela current bc the angola benguela front at the interface of the warm currents and the bc is reflected by the g inflata g bulloides assemblage an unusual coincidence of g sacculifer g bulloides in one assemblage results from the interaction of the subtropical gyre and the oceanic branch of the bc the g rubber pink n dutertrei assemblage is attributed to the warm low saline plume in front of the congo zaire river

a high resolution record of the last deglaciation in the southern tyrrhenian sea environmental and climatic evolution a multidisciplinary study was carried out on core c106 collected in the salerno gulf southern tyrrhenian sea two tephra layers recovered in the core n 18 o record of globigerinoides ruber and globigerina bulloides and seven 14 c calibrated ages provided the stratigraphic framework the core sediments cover the last 28 kyr bp seismostratigraphic analysis of a high resolution acoustic profile integrated by the dated core samples allowed us to reconstruct the architecture and age of sedimentary bodies on the continental shelf an integrated study based on different taxonomic groups nannofossils pteropods foraminifera and palynomorphs provided palaeoclimatic trends in agreement with changes in the isotopic composition of oxygen the upper part of the last glacial period the deglaciation phase and the holocene were identified correlation between marine and continental records of palaeoenvironmental changes confirms a similar reconstruction of the last deglaciation as in the central and southern mediterranean sea the late pleistocene holocene boundary was recognised at about 11 7 kyr bp between about 9 5 and 6 kyr bpand at 3 3 kyr bpsome warmer episodes were recorded the measured lower isotopic values together with some features of the fossil assemblages recorded from 9 5 to 6 kyr bp may be related to the oceanographic setting that led to the deposition of sapropel s1 in the mediterranean basin 2002 elsevier science b v all rights reserved

an ocean general circulation model view of the glacial mediterranean thermohaline circulation reconstructions of the sea surface temperature and salinity of the mediterranean sea during the last glacial maximum lgm suggest that extremely cold winters occurred in the western basin and the aegean with highly saline conditions in the eastern basin it is shown here that forcing the lgm mediterranean sea with a representative paleoclimate model results in significantly less extreme salinity conditions than are suggested by existing reconstructions modeled sea surface salinities are at most 0 1 0 2 higher than today at the lgm rather than the previously suggested 2 3 modeled sea surface temperatures over the western basin however show similar changes to these reconstructions being 3 4 c colder than present day another major difference between the lgm and control simulations is the location and spreading of subsurface water the western basin suffers complete loss of stability in the lgm winter leading to this basin becoming the source for the lgm deep water of the eastern basin the ocean general circulation model results are shown to be qualitatively consistent with cooler drier climate along the northern coast of the mediterranean but not with higher surface salinity thus refining existing paleoclimate reconstructions in the mediterranean region

dansgaard oeschger and heinrich event imprints in alboran sea paleotemperatures past sea surface temperature sst evolution in the alboran sea western mediterranean during the last 50 000 years has been inferred from the study of c37 alkenones in international marine global change studies md952043 core this record has a time resolution of 200 years allowing the study of millennial scale and even shorter climatic changes the observed sst curve displays characteristic sequences of extremely rapid warming and cooling events along the glacial period comparison of this alboran record with 18o from greenland ice greenland ice sheet project 2 core shows a strong parallelism between these sst oscillations and the dansgaard oeschger events five prominent cooling episodes standing out in the sst profile are accompanied by an anomalous high abundance of neogloboquadrina pachyderma sinistral which is confined to the duration of these cold intervals these features and the isotopic record reflect drastic changes in the surface hydrography of the alboran sea in association with heinrich events hl 5

erosional power in the swiss alps characterization of slope failure in the illgraben landslides and rockfalls are key geomorphic processes in mountain basins their quantification and characterization are critical for understanding the processes of slope failure and their contributions to erosion and landscape evolution we used digital photogrammetry to produce a multi temporal record of erosion 1963 2005 of a rock slope at the head of the illgraben a very active catchment prone to debris flows in switzerland slope failures affect 70 of the study slope and erode the slope at an average rate of 0 39 0 03 m yr the analysis of individual slope failures yielded an inventory of 2500 failures ranging over 6 orders of magnitude in volume despite the small slope area and short study period the slope failures form a characteristic magnitude frequency distribution with a rollover and a power law tail between 200 m and 1 6 106 m with an exponent of 1 65 slope failure volume scales with area as a power law with an exponent of 1 1 both values are low for studies of bedrock landslides and rockfall and result from the highly fractured and weathered state of the quartzitic bedrock our data suggest that the magnitude frequency distribution is the result of two separate slope failure processes type 1 failures are frequent small slides and slumps within the weathered layer of highly fractured rock and loose sediment and make up the rollover type 2 failures are less frequent and larger rockslides and rockfalls within the internal bedded and fractured slope along pre determined potential failure surfaces and make up the power law tail rockslides and rockfalls of high magnitude and relatively low frequency make up 99 of the total failure volume and are thus responsible for the high erosion rate they are also significant in the context of landscape evolution as they occur on slopes above 45 and limit the relief of the slope copyright 2012 john wiley sons ltd

hydrological changes in the mediterranean sea over the last 30 000 years sea surface temperatures were reconstructed over the last 30 000 years from alkenone paleothermometry sst alk and planktonic foraminifera assemblages using the modern analog technique mat sst foram along two cores of the mediterranean sea md84 632 levantine basin and md04 2797 siculo tunisian strait oxygen isotope of planktonic foraminifera g bulloides for core md04 2797 and g ruber for core md84 632 were also determined sst alk in the levantine basin indicate colder values at the last glacial maximum lgm 14 c than earlier established from mat and a cooling amplitude of 6 7 c comparable to the central mediterranean sea climatic events such as the younger dryas yd and heinrich events 1 and 2 h1 and h2 were times of significant cooling in the two cores in the eastern basin values of local seawater oxygen isotope w indicate relatively saltier waters during the lgm and deglaciation than today with increasing w values higher salinity in the eastern basin and decreasing ones lower salinity in the central mediterranean sea during cold stadials the observed alterations of surface water properties t and w in the central and eastern mediterranean at the lgm are consistent with model experiments showing slightly lower evaporation in the mediterranean than today except for the eastern basin

northern levantine and adriatic quaternary planktic foraminifera reconstruction of paleoenvironmental gradients rohling e j jorissen f j vergnaud grazzini c and zachariasse w j 1993 northern levantine and adriatic quaternary planktic foraminifera reconstruction of paleoenvironmental gradients mar micropaleontol 21 191 218 a detailed study of the planktic foraminiferal records of three cores recovered near crete shows very consistent changes unfortunately the record of t87 2 13g our shallowest core is bioturbated too much for detailed comparisons but it can still be used to discuss the general trends the mutual record of the other two cores t87 2 20g and t87 2 27g extends back to about 125 000 yr b p principal components analyses performed on the combined records of t87 2 20g and t87 2 27g yield two axes that can be interpreted paleoecologically namely a temperature axis and an annual stability axis the latter is a measure of stratification within the euphoric layer in this study we consider t87 2 20g and t87 2 27g to be reference cores for the eastern mediterranean subsequently we interprete the faunal variation in two cores from the adriatic sea in 68 5 and in 68 9 containing records extending back to 15 000 and 18 000 yr b p in the context of these reference cores this is done by calculating scores of the adriatic records along the two relevant pca axes derived from the northern levantine records also cluster analyses of the adriatic and northern levantine records are compared on the average the adriatic sea appears to have been considerably colder than the region around crete during the past 18 000 years this temperature difference was largest during the pleniglacial and only small during the holocene we found no distinct expression of a younger dryas cooling event in the adriatic records neither on our pca axis nor in the oxygen isotope record this contradicts previous paleoclimatic reconstructions based mainly on paleobotanical evidence which suggests that the younger dryas event greatly influenced circum mediterranean areas as yet we have no ready explanation for this discrepancy low annual stability values dominate both the pleniglacial and the holocene intervals of the adriatic records this suggests that homothermal conditions were as prevalent in the adriatic euphoric layer at pleniglacial times as they are at present in the present day adriatic homothermal conditions are associated with deep convection and subsequent eastern mediterranean deep water emdw formation and therefore our data suggest that emdw formation was as effective at pleniglacial times as it is at present high annual stability values in the transitional interval from 12 700 to 9600 yr b p in the adriatic records are suggestive of low emdw formation rates at that time in combination with high productivity throughout the eastern mediterranean which has previously been inferred from the planktic foraminiferal record these low emdw formation rates may have preconditioned the eastern mediterranean for sapropel formation

improving past sea surface temperature estimates based on planktonic fossil faunas a new method of past sea surface temperature sst reconstruction based on the modern analog technique prell 1985 and on the indirect approach bartlein et al 1986 has been developed the revised analog method ram applied to planktonic foraminifera this technique leads to significant improvements in modern sst reconstruction with respect to former methods our estimates are characterized by much lower residuals and a better coverage of the observed sst range moreover the error of ram estimates of past ssts is lower than that associated with former reconstructions particularly at middle and high latitudes in low latitudes cold season ssts reconstructed by ram during glacials are 1 3 c lower than previously estimated our results tend thus to reconcile paleoestimates of glacial temperatures based on planktonic microfossils and on continental data in the tropics

monitoring of high alpine mass movements combining laser scanning with digital airborne photogrammetry abstract airborne and terrestrial laser scanning are used in combination with digital airborne photogrammetry to monitor surface changes between 2009 and 2011 on rock glaciers and landslides at three mountain permafrost sites grabengufer schafberg and fluela pass in the swiss alps 3d surface changes detected through comparison of multitemporal laser scanning data as well as horizontal creep rates determined using laser scanning data and digital airborne photogrammetry are analyzed the methods applied allow comprehensive quantification of mass movements and volumetric changes which are presented in 2 5d gps ground truths are used as reference data at the grabengufer site on the basis of this a quality estimation is developed for the sites without gps reference data for changes with an extent of about 25 m 2 a level of significance of 3 cm was obtained for both horizontal and vertical displacements under optimal measurement conditions the complex dynamics of creeping and sliding permafrost features are investigated through analysis of their surface kinematics

chronology for terraces of the nalinggele river in the north qinghai tibet plateau and implications for salt lake resource formation in the qaidam basin abstract the nalinggele river located in the northern qinghai tibetan plateau is the largest river originating from the northern slope of the eastern kunlun mountains and flowing into the enclosed qaidam basin controversy exists whether the formation of its terraces reflects the history of the plateau uplift or climate changes or both the salt lakes in the enclosed qaidam basin fed by this river bear an unusual world class enrichment of lithium and boron elements which are critical resources for regional economy the concentration of lithium is one of the highest found in brine resource in the world and sourced from the upstream water of the river the chronology of the river terraces is essential to understand the plateau uplift history the regional climate change the evolution of the terminal salt lakes and the process of enrichment of the valuable elements however the age constraint for the terraces of the rivers in the east kunlun mountains is still limited and debated and no dating work has been reported yet for terraces of the nalinggele river five terraces were identified in this river in this study the terraces were dated using quartz optically stimulated luminescence osl dating the results indicate that the osl ages 7 5 ka 9 9 ka 11 3 ka and 13 1 ka of the four terraces t1 t2 t3 and t4 are consistent with geomorphic relationship and that they formed since 13 1 ka and were probably triggered by climatic change rather than by the plateau uplift the sediment of t5 is too coarse to collect osl samples and not dated based on our dating we confirm the previous view that the lithium concentration in the terminal salt lakes should have initiated since 15 13 ka we further propose that the formation of salt lakes and the enrichment of their resources in the qaidam basin should have occurred mainly in interglacial periods e g the holocene a warm and humid period not as previously thought to be in the glacial periods a dry and cold period and that during the glacial periods the basin was mainly under wind erosion

modeling a 200 yr interruption of the holocene sapropel s1 an oceanic general circulation model previously used to simulate the conditions associated with the holocene sapropel s1 is used to simulate the effects of a climate deterioration represented as a cooling event on the sapropelic circulation mode the enhanced cooling 2 3 c induces deep convection in the adriatic and the gulf of lions and intermediate water formation in the aegean where in all cases there had previously been only stagnant unventilated waters the depths of ventilation to 1250 m are in agreement with core data from this period the short decadal timescales involved in modifying the sapropelic circulation suggest that such a climatic deterioration may be associated with the interruption of s1 between 7100 and 6900 14c yr b p which divided the sapropel into two subunits

water controls the seasonal rhythm of rock glacier flow abstract rock glaciers are creeping periglacial landforms experiencing strong acceleration during recent atmospheric warming and raising concerns with regard to their future behaviour and stability high resolution kinematic observations show strong seasonal and multi annual variations in rock glacier creep but the linking mechanisms to environmental forcing remain poorly understood and lack quantitative models here we investigate the interaction between rock glacier creep and climatic forcing temperature and precipitation by developing a novel conceptual and numerical modelling approach the model is constrained and the results are compared with data from the dirru rock glacier vallis ch we are able to reproduce the observed velocity variations both in magnitude and phase on seasonal and inter annual time scales we find that water from liquid precipitation and snow melt rather than air temperature is the main driver of variations in rock glacier creep our results imply that the influence of water on rock glacier creep is fundamental and must be considered when investigating the historic and future evolution of rock glaciers

contemporary geomorphological activity throughout the proglacial area of an alpine catchment abstract quantification of contemporary geomorphological activity is a fundamental prerequisite for predicting the effects of future earth surface process and landscape development changes however there is a lack of high resolution spatial and temporal data on geomorphological activity within alpine catchments which are especially sensitive to climate change human impacts and which are amongst the most dynamic landscapes on earth this study used data from repeated laser scanning to identify and quantify the distribution of contemporary sediment sources and the intensity of geomorphological activity within the lower part of a glaciated alpine catchment odenwinkelkees central austria spatially geomorphological activity was discriminated by substrate class activity decreased in both areal extent and intensity with distance from the glacier becoming progressively more restricted to the fluvially dominated valley floor temporally geomorphological activity was identified on annual seasonal weekly and daily timescales activity became more extensive with increasing study duration but more intense over shorter timescales thereby demonstrating the importance of temporary storage of sediment within the catchment the mean volume of material moved within the proglacial zone was 4400 m 3 yr 1 which suggests a net surface lowering of 34 mm yr 1 in this part of the catchment we extrapolate a minimum of 4 8 mm yr 1 net surface lowering across the whole catchment these surface lowering values are approximately twice those calculated elsewhere from contemporary measurements of suspended sediment flux and of rates calculated from the geological record perhaps because we measure total geomorphological activity within the catchment rather than overall efflux of material repeated geomorphological surveying therefore appears to mitigate the problems of hydrological studies underestimating sediment fluxes on decadal annual time scales further development of the approach outlined in this study will enable the quantification of geomorphological activity alpine terrain stability and persistence of landforms

multiproxy approach for the reconstruction of the glacial ocean surface margo michal kucera antoni rosell mele ralph schneider claire waelbroeck mara weinelt department of geology royal holloway university of london egham tw20 0ex uk icrea and institute of environmental science and technology universitat autonoma de barcelona 08193 bellaterra catalonia spain departement de geologie et oceanographie umr5805 epoc cnrs universite de bordeaux1 33405 talence cedex france laboratoire des sciences du climat et de l environnement laboratoire mixte cnrs cea f 91198 gif sur yvette france institute for geosciences university of kiel olshausen strasse 40 d 24098 kiel germany

effects of tidal amplitude on intertidal resource availability and dispersal pressure in prehistoric human coastal populations the mediterranean atlantic transition abstract in this paper i argue that there is a growing body of evidence supporting an increasingly central position of coastal environments in human evolution and dispersals rather than as merely peripheral habitats eustatic fluctuations during glacial cycles have meant that most prehistoric coastlines are now underwater and lack of evidence to date of a close relationship between people and the coast can be most plausibly ascribed to the limited studies so far on submerged sites coastal environments provide high diversity in food resources consisting of multiple ecotones in close proximity which reduces the need to forage widely one of the richest and most easily exploited coastal resources by human populations living on the coast are molluscs from marine rocky intertidal communities which recent evidence has highlighted as important as far back as the middle palaeolithic however the density of these resources is limited by a number of factors and this varies geographically one of the main large scale factors limiting rocky intertidal mollusc densities is tidal amplitude beyond which smaller scale local factors such as exposure to wave action and shore aspect further affect species distributions the area around the strait of gibraltar is used as a case study of an area which is affected by large variations in tidal amplitudes thus allowing for quantitative comparisons between taxonomically and climatically similar regions shorelines along the mediterranean coast with reduced tidal amplitudes exhibit compressed zonations and harbour fewer macro mollusc individuals with the reverse being the case along the atlantic coast which has significantly larger tides data from middle and upper palaeolithic sites along the strait are used to establish harvested species and present day data are used to model the potential distributions and associated variables such as calorific returns of key food species an optimal foraging model is used to explore the effects of differential levels of resource availability along these coastlines results suggest that the nature and variability of the coastline has a direct influence on the tempo and mode of subsistence strategy followed and whether certain strategies can be adopted at all the possible implications of these biogeographical distributions for foraging economics dispersals and social structures in homo are discussed

the sediment delivery problem abstract the linking of on site rates of erosion and soil loss within a drainage basin to the sediment yield at the basin outlet and improved knowledge and representation of the associated processes of sediment delivery represent a major research need within the field of erosion and sedimentation and also an important scale problem in drainage basin studies this paper reviews the limitations of the sediment delivery ratio concept by considering the problems of temporal and spatial lumping and its blackbox nature some recent advances in our understanding of the sediment delivery system and its modelling are described and the lack of detailed empirical investigations is highlighted the significance of recent concern for the role of sediments in the transport of nutrients and contaminants to sediment delivery studies is introduced and the need for further work in this field is emphasised

simmax a modern analog technique to deduce atlantic sea surface temperatures from planktonic foraminifera in deep sea sediments we present a data set of 738 planktonic foraminiferal species counts from sediment surface samples of the eastern north atlantic and the south atlantic between 87 n and 40 s 35 e and 60 w including published climate long range investigation mapping and prediction climap data these species counts are linked to levitus s 1982 modern water temperature data for the four caloric seasons four depth ranges 0 30 50 and 75 m and the combined means of those depth ranges the relation between planktonic foraminiferal assemblages and sea surface temperature sst data is estimated using the newly developed simmax technique which is an acronym for a modern analog technique mat with a similarity index based on 1 the scalar product of the normalized faunal percentages and 2 a weighting procedure of the modern analog s ssts according to the inverse geographical distances of the most similar samples compared to the classical climap transfer technique and conventional mat techniques simmax provides a more confident reconstruction of paleo ssts correlation coefficient is 0 994 for the caloric winter and 0 993 for caloric summer the standard deviation of the residuals is 0 90 c for caloric winter and 0 96 c for caloric summer at 0 m water depth the sst estimates reach optimum stability standard deviation of the residuals is 0 88 c at the average 0 to 75 m water depth our extensive database provides sst estimates over a range of 1 4 to 27 2 c for caloric winter and 0 4 to 28 6 c for caloric summer allowing sst estimates which are especially valuable for the high latitude atlantic during glacial times an electronic supplement of this material may be obtained on adiskette or anonymous ftp from kosmos agu org login toagu s ftp account using anonymous as the username and guestas the password go to the right directory by typing cd append typels to see what files are available type get and the name of the file toget it finally type exit to leave the system paper 95pa01743 simmax a modern analog technique to deduce atlantic sea surfacetemperatures from planktonic foraminifera in deep sea sediments uwepflaumann josette duprat claude pujol and laurent d labeyrie diskette may be ordered from american geophysical union 2000florida avenue n w washington dc 20009 payment mustaccompany order

abrupt cold spells in the northwest mediterranean hitherto unknown abundance peaks of left coiling l c neogloboquadrina pachyderma from a gulf of lions piston core indicate that abrupt cold spells associated with atlantic heinrich events affected the mediterranean n pachyderma l c is typical of sub polar waters in the open ocean the southern edge of its glacial north atlantic bioprovince reached south portugal only trace abundances of n pachyderma l c are known from quaternary mediterranean sediments suggesting that no significant invasions occured via the strait of gibraltar the gulf of lions abundance peaks therefore seem to reflect area specific thriving of a normally rare but indigenous taxon in the western mediterranean through local favorable habitat development the general planktonic foraminiferal record suggests that the basic hydrographic regime in the gulf of lions with wintertime deep convective overturn was relatively stable over the past 60 kyr under these conditions high abundances of n pachyderma l c would essentially imply temperature reductions of the order of 5 8 relative to the present

monitoring and modelling morphological change in a braided gravel bed river using high resolution gps based survey recent research in fluvial geomorphology has emphasized the direct monitoring of channel topography as a useful tool to better understand the interrelationship between river form and process and in particular to estimate bedload transport rates and reach scale sediment budgets until recently however this morphometric approach has been limited to comparison of repeatedly surveyed cross sections with the associated problems of low frequency sampling and an emphasis on cross stream as opposed to downstream morphological dynamics recent advances in analytical photogrammetry have however permitted the acquisition of data at sufficient resolutions to represent macroform 101 m and microform 10 m channel geometry in fully three dimensions while inherently spatially distributed the photogrammetric approach to land surveying is however restricted to observable areas of the channel and is thus of limited use in the subaqueous zone especially if flows are turbid or highly coloured this paper presents an alternative approach to the study of three dimensional morphological dynamics of a divided reach of the gravelly river feshie scotland in which topographic survey of both exposed and submerged areas of the reach was undertaken using the global positioning system gps survey results from two field programmes in 1998 and 1999 are presented in which a geotronics geotracer 2000 real time kinematic gps receiving unit was used to survey a 200 80 m reach rapid radial survey methods were employed permitting the collection of 2000 survey points per day giving a mean density over the 13 ha reach of 1 1 points per square metre a detailed assessment of survey errors and dem quality is presented and a limit of detection of c 10 cm proposed as an upper threshold for the identification of significant change between dems preliminary interpretation of channel dynamics in 1998 99 reveals relatively little change to the overall macroscale reach structure dem differencing techniques however highlight important local changes including the progradation of submerged bar fronts bar head aggradation and scour along major channel thalwegs and the erosion of fines from sloughs copyright 2000 john wiley sons ltd

sediment transfer rates of two active rockglaciers in the swiss alps abstract high mountain geosystems are characterized by an extensive transfer of mass and energy reflected in its geomorphological processes shaping the landscape within the periglacial belt rockglaciers represent important sediment storages and transport components in this study sediment transfer rates are quantified for two rockglaciers with different characteristics based on a multi method approach combining geomorphological mapping dtm analyses digital photogrammetry and geodetic survey for the first time different velocity values resulting from a kinematic monitoring over two decades are included due to the different characteristics of the landforms especially thickness and horizontal velocity a wide range of sediment transfer rates results from this study between 0 24 and 1 1 million t a with the maximum value for a rockglacier with a relatively small mass but high deformation rates

increased seasonality in the western mediterranean during the last glacial from limpet shell geochemistry the seasonal cycle is a fundamental aspect of climate with a significant influence on mean climate and on human societies assessing seasonality in different climate states is therefore important but outside the tropics very few palaeoclimate records with seasonal resolution exist and there are currently no glacial age seasonal resolution sea surface temperature sst records at mid to high latitudes here we show that both mg ca and oxygen isotope 18o ratios in modern limpet patella shells record the seasonal range of sst in the western mediterranean a region particularly susceptible to seasonal change analysis of a suite of fossil limpet shells from gibraltar shows that sst seasonality was greater during the last glacial by 2 c as a result of greater winter cooling these extra tropical seasonal resolution sst records for the last glacial suggest that the presence of large ice sheets in the northern hemisphere enhances winter cooling this result also indicates that seasonality in the mediterranean is not well represented in most palaeoclimate models which typically show little change in seasonal amplitude and provides a new test for the accuracy of climate models

modeling the distribution and seasonality of neogloboquadrina pachyderma in the north atlantic ocean during heinrich stadial 1

the geomorphic significance of rock glaciers estimates of rock glacier debris volumes and headwall recession rates in west greenland to obtain knowledge on rockwall retreat rates at sites with rock glaciers an inventory of about 400 individual rock glacier sites in west greenland was carried out by means of field studies and using aerial photographs and topographic maps a number of sites with ice cored moraines beyond normal glaciers were included in the analysis for comparative purposes the estimated debris volume was compared with the size of the source headwall the result of the inventory suggests that the presence of rock glaciers indicates extraordinary high retreat rates for rock free faces above especially headwalls above glacier derived rock glaciers are exposed to high weathering rates and thereby presumably delimit critical ranges regarding altitude for headwall retreat rates the relation of such a critical altitudinal range to other regional concepts such as glaciation level gl and glacier equilibrium line is discussed from this comments are also made on the relation between various permafrost zones and the typical regional climate within the maximum headwall weathering altitude at sites with active rock glaciers finally the potential importance of this range of maximum weathering for understanding the long term evolution of high relief cold climate landscapes is emphasised

mapping and quantifying sediment transfer between the front of rapidly moving rock glaciers and torrential gullies abstract the sedimentary connection which may occur between the front of active rock glaciers and torrential channels is not well understood despite its potential impact on the torrential activity characterizing the concerned catchments in this study dems of difference dods covering various time intervals between 2013 and 2016 were obtained from lidar derived multitemporal dems for three rapidly moving rock glaciers located in the western swiss alps the dods were used to map and quantify sediment transfer activity between the front of these rock glaciers and the corresponding underlying torrential gullies sediment transfer rates ranging between 1500 m3 y and 7800 m3 y have been calculated depending on the sites sediment eroded from the fronts generally accumulated in the upper sectors of the torrential gullies where they were occasionally mobilized within small to medium sized debris flow events a clear relation between the motion rates of the rock glaciers and the sediment transfer rates calculated at their fronts could be highlighted along with the size of the frontal areas rock glacier creep rates influence thus directly sediment availability in the headwaters of the studied torrents the frequency magnitude of debris flow events varied between sites and was mainly related to the concordance of local factors such as topography water availability sediment availability or sediment type

glacial mediterranean sea surface temperatures based on planktonic foraminiferal assemblages we present a new reconstruction of mediterranean sea surface temperatures sst during the last glacial maximum lgm a calibration data set based on census counts of 23 species of planktonic foraminifera in 129 north atlantic and 145 mediterranean core top samples was used to develop summer winter and annual average sst reconstructions using artificial neural networks anns and the revised analogue method ram prediction errors determined by cross validation of the calibration data set ranged between 0 5 and 1 1 c with both techniques being most successful in predicting winter ssts glacial reconstructions are based on a new expanded data set of 273 samples in 37 cores with consistent minimum level of age control the new lgm reconstructions suggest that the east west temperature gradient during the glacial summer was 9 c whereas during the glacial winter the gradient was 6 c both some 4 c higher than that existing today in contrast to earlier studies our results tend to suggest much cooler sst estimates throughout the glacial mediterranean particularly in the eastern basin where previous sst reconstructions indicated a decrease of only 1 c our new sst reconstructions will provide the modelling community with a detailed and updated portrayal of the mediterranean sea during the lgm setting new targets on which glacial simulations can be tested

western mediterranean planktonic foraminifera events and millennial climatic variability during the last 70 kyr abstract detailed study of associations of planktonic foraminifera in cores md95 2043 and odp 977 located in the alboran sea mediterranean sea has allowed the identification of 29 new faunal events defined by abrupt changes in the abundances of neogloboquadrina pachyderma right and left coiling turborotalita quinqueloba globorotalia scitula globorotalia inflata globigerina bulloides and globigerinoides ruber white and pink varieties the age model for odp 977 was based on that of md95 2043 cacho et al 1999 paleoceanogr 14 698 705 on the isotopic stratigraphy and on two ams 14c measurements sea surface temperatures ssts were estimated for the last 54 kyr using the modern analog technique mat and were compared with the ssts provided by the uk 37 method the uk 37 record is very similar to the mat annual mean temperature record for the last 8 kyr however for older times alkenone derived temperatures are consistently higher than the annual mat temperatures this offset may be due to an underestimation of the sst provided by the planktonic foraminiferal method for glacial times to an overestimation of the uk 37 record or to changes in the seasonal production of alkenones most of the variability in the fauna is related to the millennial variability of heinrich and dansgaard oeschger d o events during heinrich events hes and most of the other d o stadials g bulloides t quinqueloba and g scitula increased while n pachyderma right coiling g inflata and g ruber decreased by contrast n pachyderma left coiling was only abundant in the hes the main component of the associations n pachyderma right coiling follows a general trend similar to that of sea level and 18o this species reached its highest abundance during the last glacial maximum when sea level was at a lower position the occurrence of a shallower nutricline owing to a shallowing of the interface between atlantic inflowing and mediterranean outflowing waters could have favoured the development of neogloboquadrinids in the vicinity of the strait of gibraltar

inventorying slope movements in an alpine environment using dinsar differential sar interferometry dinsar is a technique that can be used to detect and characterize slope movements it is investigated here as a tool for establishing a detailed overview of complex slope movements at a regional scale in an alpine context this paper gives specific recommendations to use and to understand dinsar signals in mountainous areas located above the tree line excluding glaciated areas it proposes a systematic procedure based on accurate interpretations of interferometric signals from a large dinsar dataset to locate and estimate the displacement rate of moving zones the methodology was successfully applied in the western swiss alps where about 1500 moving objects were detected above the tree line using a large dataset of ers and jers interferograms dating from the 1990s the dinsar detected movements had a displacement rate ranging from a few centimeters to several meters per year and were attributed to various types of mass wasting phenomena rock glaciers landslides etc this kind of inventory derived from dinsar can be used as a preliminary tool for natural hazard management and process understanding in mountain areas as automatic data archiving and systematic acquisition of sar data are ensured worldwide for most sar sensors a similar methodology can basically be applied in many other parts of the globe also by using data from current sar sensors as long as a high resolution dem is available copyright 2014 john wiley sons ltd

deep sea circulation in the alboran sea alboran sea circulation between 220 and 1100 m depth is studied interaction between three types of water masses in this area causes a complicated flow pattern atlantic water flowing as a jet through the strait of gibraltar into the mediterranean often forms an anticyclonic gyre to the depth of 200 m and its features are now well documented a few works based on geostrophic calculations and bernoulli s equation treat the deep flow nine free floats were released at different depths and locations from january to may 1982 and acoustically tracked every 2 hours for 40 to 90 days acoustical tracking was done from three listening stations moored in the area the tracks of the floats at all depths from 220 to 1100 m revealed broad and slow approximately 2 5 cm s cyclonic circulation located under the surface anticyclonic gyre part of the flow following the bottom topography turned near the moroccan continental slope as a jet approximately 5 cm s to gibraltar and part turned to the east following the southern boundary of the deep channel to the isle of alboran

late quaternary changes in mediterranean intermediate water density and formation rate three recently acquired eastern mediterranean cores containing late quaternary sediments display a marked faunal contrast between the holocene and older sapropels it is suggested that the absence of neogloboquadrinids in the holocene sapropel and their abundance in older sapropels reflect differences in food availability related to the extent of development of a deep chlorophyll maximum layer dcm and the intensity of new primary production associated with this layer the depth of such a layer which consists of phytoplankton with a characteristic taxonomic composition is determined by the vertical hydrodynamical structure during deposition of the older sapropels the pycnocline was apparently positioned well above the base of the euphotic layer a situation that favors a pronounced dcm and an associated relatively high rate of new production shallowing of the pycnocline implies a relatively low density of the mediterranean intermediate water miw on the other hand during deposition of the holocene sapropel the pycnocline had apparently vanished due to termination of miw formation

tyrrhenian sea tephrochronology of the oxygen isotope record for the past 60 000 years abstract a chronology of the marine oxygen isotope record of the past 60 ka is proposed by correlating eight marine ash layers with terrestrial volcanic deposits dated by the 14c and or k ar methods detailed oxygen isotope analyses were made on the planktonic foraminifera of three cores collected in the central tyrrhenian sea the origin of the ash layers was determined by major and trace elements analyses then the major pyroclastic terrestrial deposits were sampled and analysed in order to provide land sea correlations two ash layers occurred during the warm event that followed the first step of the deglaciation and which was dated at 12 6 0 5 ka b p another ash layer is present near the last glacial maximum that we have dated at 17 5 0 3 ka b p during isotopic stage 3 five ash layers were recognized and dated which allowed us to assign ages to the isotopically light oxygen peaks warmer interstadials at 31 1 5 ka and 33 4 1 6 ka denekamp at 37 5 2 ka hengelo and successively at 49 2 ka 52 4 2 2 ka 57 2 2 ka and 60 5 2 2 ka moershoofd complex

methodological sensitivity of morphometric estimates of coarse fluvial sediment transport abstract the estimation of fluvial sediment transport rate from measurements of morphological change has received growing recent interest the revival of the morphological method reflects continuing concern over traditional methods of rate determination but also the availability of new survey methods capable of high precision high resolution topographic monitoring remote sensing of river channels through aerial digital photogrammetry is a potentially attractive alternative to labour intensive ground surveys however while photogrammetry presents the opportunity to acquire survey data over large areas data precision and accuracy particularly in the vertical dimension are lower than in traditional ground survey methods this paper presents results of recent research in which digital elevation models dems have been developed for a reach of a large braided gravel bed river in scotland using both digital photogrammetry and high resolution rtk gps ground surveys a statistical level of change detection is assessed by comparing surfaces with independent check points the methodological sensitivity of the annual channel sediment budget 1999 2000 to the threshold is presented results suggest that while the remote survey methods employed here can be used to develop qualitatively convincing moderate precision dems of channel topography rmse 0 21 m the remaining errors imply significant limits on reliable change detection which lead to important information losses tests at a 95 confidence interval for change detection show that over 60 of channel deposition and 40 of erosion may be obscured by the lower level of precision associated with photogrammetric monitoring when compared to ground survey measurements this bias reflects the difficulty of detecting the topographic signature of widespread but shallow deposition on bar tops

overview of glacial atlantic ocean mapping glamap 2000 glamap 2000 presents new reconstructions of the atlantic s sea surface temperatures sst at the last glacial maximum lgm defined at both 21 500 18 000 years b p last isotope maximum and 23 000 19 000 years b p maximum glacial sea level low stand and orbital minimum of solar insolation epilog working group see mix et al 2001 these reconstructions use 275 sediment cores between the north pole and 60 s with carefully defined chronostratigraphies four categories of core quality are distinguished more than 100 core sections provide a glacial record with subcentennial to multicentennial scale resolution sst estimates are based on a new set of almost 1000 reference samples of modern planktic foraminifera and on improved transfer function techniques to deduce sst from census counts of microfossils including radiolarians and diatoms new proxies also serve to deduce sea ice boundaries the glamap 2000 sst patterns differ significantly in crucial regions from the climap 1981 reconstruction and thus are important in providing updated boundary conditions to initiate and validate computational models for climate prediction

glacial north atlantic sea surface conditions reconstructed by glamap 2000 the response of the tropical ocean to global climate change and the extent of sea ice in the glacial nordic seas belong to the great controversies in paleoclimatology our new reconstruction of peak glacial sea surface temperatures ssts in the atlantic is based on census counts of planktic foraminifera using the maximum similarity technique version 28 simmax 28 modern analog technique with 947 modern analog samples and 119 well dated sediment cores our study compares two slightly different scenarios of the last glacial maximum lgm the environmental processes of the ice age land oceans glaciers epilog and glacial atlantic ocean mapping glamap 2000 time slices the comparison shows that the maximum lgm cooling in the southern hemisphere slightly preceeded that in the north in both time slices sea ice was restricted to the north western margin of the nordic seas during glacial northern summer while the central and eastern parts were ice free during northern glacial winter sea ice advanced to the south of iceland and faeroe in the central northern north atlantic an anticyclonic gyre formed between 45degrees and 60degreesn with a cool water mass centered west of ireland where glacial cooling reached a maximum of 12degreesc in the subtropical ocean gyres the new reconstruction supports the glacial to interglacial stability of sst as shown by climap project members climap 1981 the zonal belt of minimum sst seasonality between 2degrees and 6degreesn suggests that the lgm caloric equator occupied the same latitude as today in contrast to the climap reconstruction the glacial cooling of the tropical east atlantic upwelling belt reached up to 6degrees 8degreesc during northern hemisphere summer differences between these simmax based and published u37 k and mg ca based equatorial sst records are ascribed to strong sst seasonalities and sst signals that were produced by different planktic species groups during different seasons

environmental processes of the ice age land oceans glaciers epilog knowledge of the state of the earth at the last glacial maximum lgm an interval around 21 000 years ago is an important benchmark for understanding the sensitivity of global environmental systems to change much progress in understanding climates of the lgm has occurred in the 20 years since the end of the climap project of the 1970s climate long range investigation mapping and prediction here we review this progress based on presentations and discussion at a rst open science meeting of the epilog project environmental processes of the ice age land oceans glaciers held in delmenhorst germany may 1999 we outline key controversies and document protocols for epilog contributions so that a new synthesis of the lgm earth can emerge as an open project of the world s community of scientists 2001 elsevier science ltd all rights reserved

application of artificial neural networks to paleoceanographic data abstract artificial neural networks are computer systems that have the ability to learn a set of output or target vectors from a set of input vectors learning is achieved by self adjustment of a set of parameters to minimize the error between a desired output and the actual network output we have explored the potential of this approach in paleoceanography by application of a neural network algorithm to a problem involving prediction of sea surface water temperatures from relative abundances of planktonic foraminifer species in the southern indian ocean we employed a backpropagation bp network to assess how well it was able to predict the actual summer and winter surface water temperatures we compared the results with those obtained from statistical methods previously used for temperature predictions imbrie kipp transfer functions the modern analog technique and soft independent modelling of class analogy the efficiency of predictions was tested using the leaving one out technique in which each of the observations in the data set is left out one at a time while the remaining observations are used to generate a predictor the accuracy of the predictor is then tested on the observation left out by comparison with its actual value a set of tests using 1 2 3 4 5 and 10 neurons processing elements in a 3 layer bp network showed that a network with 3 neurons gave the smallest errors of prediction for both summer and winter temperatures 0 71 and 0 76 respectively corresponding errors for the statistical pattern recognition techniques ranged between 1 01 and 1 26 for summer temperatures and 1 05 1 13 for winter temperatures hence predictions of paleotemperatures from new data on planktonic foraminifer relative abundances in the southern indian ocean may be made with a precision of 0 7 0 8 c using the bp network and 1 0 1 3 c using the statistical pattern recognition procedures the bp network was thus the most successful among the methods employed here for temperature predictions artificial neural networks may therefore be seen as a viable alternative to more conventional approaches to data analysis in paleoceanography

comparison of statistical and artificial neural network techniques for estimating past sea surface temperatures from planktonic foraminifer census data we present the first detailed and rigorous comparison of six different computational techniques used to reconstruct sea surface temperatures sst from planktonic foraminifer census data these include the imbrie kipp transfer functions iktf the modern analog technique mat the modern analog technique with similarity index simmax the revised analog method ram and for the first time a set of back propagation artificial neural networks ann trained on a large faunal data set including a modification where geographical information was added among the input variables annd by training the techniques on an identical database we were able to explore the differences in sst reconstructions resulting solely from the use of different mathematical methods the comparison indicates that while the iktf technique consistently shows the worst performance ann and ram perform slightly better than mat and that the inclusion of the geographical information into the training database simmax and annd further improves the accuracy of modern sst estimates however when applied to an independent validation data set and an additional fossil data set the results did not conform to this ranking the largest differences in the reconstructed sst values occurred between groups of techniques with different approaches to sst reconstruction that is ann and annd produced sst reconstructions significantly different from those produced by ram simmax and mat the application of the various techniques to the validation data set which allowed comparison of sst reconstructions with instrumental records suggests that artificial neural networks might provide better paleo sst estimates than the other techniques

speleothem isotopic evidence of winter rainfall variability in northeast turkey between 77 and 6 ka an oxygen isotope record from a stalagmite that grew between 77 ka and 6 ka in northeast turkey contains both a strong precessional signal and sub orbital oscillations similar to those in greenland ice cores and chinese speleothem records of monsoon intensity fluid inclusion evidence of a negative shift in the isotopic composition of dripwater during the lateglacial supports interpretation of the isotope curve as an insolation forced record of changes in rainfall seasonality the high amplitude millennial scale fluctuations are caused by rapid changes in rainfall seasonality and or switching of moisture source areas both of which are associated with the stadial interstadial climatic oscillations linked to the changing modes of the north atlantic meridional overturning circulation moc winter rainfall maxima in northeast turkey coincide with interstadial conditions in greenland and with periods of intensified asian monsoon activity the isotopic shifts in the record are in antiphase with and are generally much larger in amplitude than published data from stalagmites in northwest turkey most likely because of differing moisture source areas carbon isotope ratios are probably kinetically enriched by partial degassing of seepage water in the epikarst but although often difficult to decypher particularly during marine isotope stage mis 2 broadly support the interpretations of the oxygen data

reconstruction of the glacial atlantic and pacific sea surface temperatures from assemblages of planktonic foraminifera multi technique approach based on geographically constrained calibration datasets

sea surface temperature during the quaternary at odp sites 976 and 975 western mediterranean abstract based on the relative abundances of the planktonic foraminifera species found in quaternary samples from odp sites 976 alboran sea and 975 menorca rise and using a modern analog technique winter and summer sea surface temperatures were estimated frequency distributions of temperatures are asymmetrical more so at odp site 976 where there is a greater abundance of samples from the warm part of the temperature range during the quaternary there is a general tendency for temperatures to fall with an overall diminution of 1 c for the winters and of more than 2 c for the summers overall mean temperatures and those of the biostratigraphic intervals identified are higher at odp site 975 than at 976 when differences are statistically significant the q1 interval i e the oldest in the quaternary is colder than the upl i e terminal pliocene and the q2 interval the q3 interval is also colder than the q2 interval and the q4 interval i e the most recent interval differences between intervals general trends and the asymmetries of frequency distributions cannot be explained as linear responses to insolation the stratigraphic series from odp site 976 was dated by correlating the relative maxima and minima of the summer temperature series with those of insolation during the month of july at 65 n it was found that 26 2 of the variance of the time series of temperatures was concentrated in the harmonics related to precession and obliquity while 19 was located in those related to eccentricity there are indications of the need to add lags and leads to the age of temperature spikes with respect to insolation but such delays and leads cannot be quantified precisely

late quaternary central mediterranean biochronology jorissen f j asioli a borsetti a m capotondi l de visser j p hilgen f j rohling e j van der borg k vergnaud grazzini c and zachariasse w j 1993 late quaternary central mediterranean biochronology mar micropaleontol 21 169 189 a high resolution biochronology is presented for the late quaternary of the central mediterranean in the late pleistocene holocene successions three assemblage zones are distinguished on the basis of frequency patterns of planktic foraminifera the age of these zones is determined by accelerator mass spectrometry ams t4c dating the zonal boundaries are dated at 12 700 yr b p the end of termination la and 9600 yr b p the start of termination ib respectively the ams dates show that major changes in the planktic and benthic realms occurred synchronously over wide areas although records of individual species may show important regional differences in the studied areas resedimentation processes revealed by anomalous successions of 14c dates play a far more important role than indicated by the sedimentological and micropaleontological data possibly these processes contribute to the very high accumulation rates in the glacial zone ill although the ams technique has increased the accuracy of lac measurements of older carbonate may still lead to substantial age differences between areas with different sedimentary regimes

modeling the paleocirculation of the mediterranean the last glacial maximum and the holocene with emphasis on the formation of sapropel s 1 an ocean general circulation model is used to simulate the thermohaline circulation in the mediterranean sea during the last glacial maximum and the holocene when the sapropel s1 was deposited the model is forced by prescribed surface temperatures and salinities where present day values lead to very realistic surface buoyancy fluxes different paleoreconstructions for the surface salinity and temperature distributions during these periods are tested in both periods under all reconstructions antiestuarine flow is maintained at gibraltar and sicily the holocene circulation has fresh intermediate water produced in the adriatic and an upward salt flux from the old waters below help maintain its outflow at sicily the depth of ventilation around the basin is broadly consistent with the shallowest sapropel layers observed shoaling of the eastern pycnocline occurs in all experiments in both periods possibly indicating enhanced productivity although the reasons for this are different in each case

controlling factors on a paleo lake oxygen isotope record yammouneh lebanon since the last glacial maximum abstract late quaternary paleoclimatic changes in the levant are difficult to extract from carbonate oxygen isotope records partly because the factors controlling the terrestrial 18 o signals are not fully understood in this region characterized by sharp climatic gradients here we address this purpose by presenting the first 14 c dated isotope record from the northern levant the record is based on oxygen isotopes from ostracod shells from lacustrine palustrine deposits accumulated in a small karstic hydrologically open basin yammouneh located on the eastern flank of mount lebanon we have first constructed a composite isotopic record obtained from three different ostracod taxa this yields an oxygen isotope record of ostracods ost related to the most widespread species ilyocypris inermis and converted to 18 o values coeval with calcite precipitated in equilibrium c with the lake water l as with other records from the mediterranean region the yammouneh profile shows maximum and minimum c values during the lgm and the early holocene respectively and a slight late holocene increase in order to discuss the potential causes of the observed 18 o values fluctuations e g changes in the isotopic composition of the moisture source temperature precipitation minus evaporation p e balance or atmospheric circulation we tentatively reconstruct the lake water isotope composition by correcting the c values for lake water temperature using regional paleotemperature estimates inferred l values were then corrected for the isotopic composition of the eastern mediterranean sea surface water the moisture source derived from planktonic foraminifera 18 o values corrected for alkenone based sea surface temperature our study suggests that holocene l fluctuations are primarily linked to changes in the sea surface water composition source effect amplified by enhanced inland rainfall during the early holocene during the lgm low l values at yammouneh are likely due to the ground temperature effect on the rainfall isotope composition possibly associated with a steeper altitudinal thermal gradient inland and with changes in air mass trajectories over the mediterranean sea

atmospheric gcm response to an idealized anomaly of the mediterranean sea surface temperature the atmospheric response to an idealized 2 k cooling of the mediterranean sea is studied in a general circulation model gcm in the downstream region from the eastern mediterranean basin to the whole asian continent following the sub tropical jet stream a baroclinic response is produced with high pressure near the surface and low pressure in the upper layers it is the direct response to the mediterranean cooling and it needs only a few days to be established teleconnections with strong zonal characteristics are found following the sub tropical jet stream to the north pacific and north america propagating further across the north atlantic towards northern europe two remarkable remote features are the deepening of the aleutian low in the north pacific and the weakening of the icelandic low in the north atlantic these two teleconnections form and grow in several days in the north pacific and several tens of days in the north atlantic both have a quasi barotropic vertical structure it is believed that they are the consequence of complex interactions between the mean flow and the transient eddies in the atmosphere

palaeoceanography of the last deglaciation in the alboran sea western mediterranean stable isotopes and planktonic foraminiferal records abstract oxygen isotope changes of the foraminiferal species globigerina bulloides and uvigerina peregrina eleven radiocarbon dates on the sediment fraction above 50 m and 13 biostratigraphical events allow us to correlate and to date the sediment record of the last climatic cycle in four cores from the alboran sea nine ecozones are recognized which differ from those previously established for atlantic sediments cored immediately west of gibraltar these ecozones can be grouped into two broad phases from the last glacial maximum up to near 9 500 yr b p cold north atlantic microfaunas are the major component of the assemblages during this interval dominant species replace each other according to the varying temperature and density stratification of the water masses from 9 500 yr b p up to the present time subtropical forms from the central atlantic dominate the northern atlantic forms an abrupt increase in the percentages of g inflata occurred near 7 000 b p this event was diachronous within the mediterranean during the last glacial g inflata was endemic inside the mediterranean and its abrupt increase near the end of the deglaciation did not result from replenishment from the atlantic between 4 000 and 5 000 yr b p percentages of g bulloides also increased abruptly warming conditions associated with the onset of a seasonal thermal stratification and a contrasting winter vertical convection are strongly suggested

prediction of sea surface temperatures in the western mediterranean sea by neural networks using satellite observations 1 we use artificial neural networks anns to predict sea surface temperatures ssts in the western mediterranean sea the anns are trained with meteorological variables as input and concurrent satellite derived ssts as target the trained anns predict well both the seasonal and the interannual variability of sst in that region we also reproduce the impact of the heat wave that occurred during the summer of 2003 on the ssts of the western mediterranean sea the ann technique allows us to predict sst maps in the western alboran sea for time coordinates before sst satellite availability the presence and later partial collapse of the western alboran gyre throughout 1980 is detected with good agreement by both the ann predictions and the concurrent results from a 3 d circulation model the same methodology is used to reconstruct incomplete sst satellite images

evidence for enhanced mediterranean thermohaline circulation during rapid climatic coolings molecular biomarkers c37 alkenones n nonacosane and n hexacosanol and toc are used together with benthic 18o and 13c data to document the hydrographic response of the western mediterranean sea to rapid climatic variability these proxies are recorded in core md 95 2043 alboran sea affording the study of the dansgaard oeschger d o and heinrich he variability during the last glacial period the results suggest that rapid changes in the western mediterranean thermohaline circulation occurred in parallel to sea surface temperature oscillations enhanced deep water ventilation occurred during cold intervals he and d o stadials probably driven by a strengthening of north westerly wind over the north western mediterranean sea in contrast decreased intensity of the thermohaline circulation is detected during warm intervals d o interstadials which led to low oxygenated deep water masses and better preservation of the organic matter in the sediment

comparison of gully erosion estimates using airborne and ground based lidar on santa cruz island california abstract gully erosion removes comparatively large volumes of soil from small areas it is often difficult to quantify the loss of soil because the footprint of individual gullies is too small to be captured by most generally available digital elevation models dems such as the usgs national elevation dataset airborne lidar light detection and ranging has the potential to provide the required data density but an even newer class of ground based sensors may provide better local resolution at lower cost in this study we compared digital elevation models produced by airborne and ground based lidar systems with ground based geomorphic and geodetic survey data to determine their utility in quantifying volumetric soil loss due to gully erosion in a heavily degraded watershed 7 55 10 2 km 2 on southwestern santa cruz island in southern california volumetric estimates of the eroded sediment were produced by comparing the lidar derived dems of the gully system to a modeled pre erosion surface average point densities were significantly higher for the ground based lidar system and provided more detailed information however its limited scanning footprint and side looking orientation presented serious challenges in collecting continuous data from deeply incised gullies making the airborne system preferable for this type of investigation and likely for most applications where heavy topographic shadowing is prevalent

linking onshore offshore sediment dispersal in the golo source to sink system corsica france during the late quaternary abstract spatial and temporal relationships between climate tectonics and sea level have a primary control on sediment transport storage and deposition in onshore and offshore depositional environments although many simplistic models have tried to predict onshore system behavior and sediment partitioning between onshore and offshore depositional environments in response to changes in these boundary conditions the alluvial response to changes in external forcings coupled with autogenic processes can be highly complex and unpredictable the golo source to sink system on the eastern margin of the island of corsica in the mediterranean sea provides an ideal laboratory to study sediment partitioning in both onshore and offshore realms the terrestrial part of the system consists of the golo river which debouches onto a narrow shelf 10 km which in turn passes into a narrow 45 km confined basin known as the corsica trough dominated by submarine fan deposits estimates on timing of late quaternary fluvial aggradation are compared with timing of sediment storage on the shelf and on the basin floor fan the results indicate that onshore deposition and storage of sediment in the fluvial system may occur both during sea level highstand transgression and lowstand volume calculations from the alluvial record show that onshore storage is relatively low 13 relative to the overall sediment budget comparing estimated deposition rates with a sediment prediction model further suggests that deep sea fan sedimentation rates at times may be up to 50 higher or 25 lower than what is being supplied by the river indicating temporary storage and release of sediment on the shelf on average however there is good agreement between predicted and calculated sediment volumes in the golo system the study demonstrates the value of investigating the entire source to sink system in order to obtain a comprehensive understanding of sediment dispersal between onshore and offshore depositional environments over 104 year timescales observations suggest that alternating periods of aggradation and degradation of the golo river are controlled by system thresholds controlled from within the catchment comparison with climate proxy data and timing of major alluviation events elsewhere in the mediterranean region supports the notion that each source to sink system has a unique threshold that must be exceeded to induce regional aggradation and subsequent terrace formation the same is also inferred for timing of sediment dispersal to the deep sea environment in addition preservation of onshore sediment is controlled by local factors such as uplift rate and its impact on the aggradational response it is therefore expected that the onshore record may be diachronous on local regional and global scales making detailed correlation difficult except for the most extreme events finally stream incision rates appear to be one to two orders of magnitude higher than regional hinterland denudation rates indicating that the golo system is characterized by increasing landscape relief

sediment connectivity a framework for understanding sediment transfer at multiple scales a major challenge for geomorphologists is to scale up small magnitude processes to produce landscape form yet existing approaches have been found to be severely limited new ways to scale erosion and transfer of sediment are thus needed this paper evaluates the concept of sediment connectivity as a framework for understanding processes involved in sediment transfer across multiple scales we propose that the concept of sediment connectivity can be used to explain the connected transfer of sediment from a source to a sink in a catchment and movement of sediment between different zones within a catchment over hillslopes between hillslopes and channels and within channels using fluvial systems as an example we explore four scenarios of sediment connectivity which represent end members of behaviour from fully linked to fully unlinked hydrological and sediment connectivity sediment travel distance when combined with an entrainment parameter reflecting the frequency magnitude response of the system maps onto these end members providing a coherent conceptual model for the upscaling of erosion predictions this conceptual model could be readily expanded to other process domains to provide a more comprehensive underpinning of landscape evolution models thus further research on the controls and dynamics of travel distances under different modes of transport is fundamental copyright 2014 john wiley sons ltd

from geotechnical analysis to quantification and modelling using lidar data a study on rockfall in the reintal catchment bavarian alps germany in the year 2007 enhanced rockfall activity was observed within the scarp of a 500 bp rockslide in the reintal catchment northern calcareous alps germany the largest of a series of events took place in august when almost 50000 m of rock were detached from the subvertical rock face and deposited on a talus cone in this case study we focus on three aspects of rockfall research first we compile detailed geomorphological and geotechnical findings to explain the causes of the recent events the results of laboratory tests and stability estimations suggest that rockfall activity will persist in the future as the old rockslide scarp still contains unstable rock masses second we use digital elevation data from a pre event airborne lidar survey als and post event terrestrial laserscanning tls to quantify landform changes and the mass balance of the rockfall event s the widespread availability of als elevation data provides a good opportunity to quantify fresh events using a comparatively inexpensive tls survey this approach is complicated by uncertainties resulting from the difficult coregistration of als and tls data and the specific geometric problems in steep als and flat tls terrain it is therefore limited to at least medium sized events third the event s is simulated using the results of the lidar surveys and a modified gis based rockfall model in order to test its capability of predicting the extent and the spatial distribution of deposition on the talus cone results show that the model generally reproduces the process domain and the spatial distribution of topographic changes but frequently under and over estimates deposition heights copyright 2011 john wiley sons ltd

response of the pelagic environment to palaeoclimatic changes in the central mediterranean sea during the late quaternary abstract three central mediterranean deep sea cores have been studied to reconstruct the palaeoclimatic history of the basin over the time interval 34 0 kyr bp the intensity and duration of the climatic events that occurred in the mediterranean sea during the last glacial postglacial transition were estimated by observing compositional changes in the planktonic foraminifera and calcareous nannoplankton coccolithophores assemblages together with a reconstruction of sea surface temperatures using the modern analogue technique and u 37 k index the 18 o signal and pteropod fluxes the application of two independent and well established techniques for the determination of the past sst led to a number of considerations about the accuracy and efficacy of the use of such methodologies in the mediterranean sea notoriously dominated by local factors and characterised by a number of independent environments the recognition of millennial to centennial climatic instabilities in both the sst and microfossil records was possible because of the high resolution of the study a succession of nine main biozones and six sub zones based on the major changes in the planktonic foraminifera records has been recognised and compared with grip and gisp2 ice cores 18 o values and with records from four other studies from the central mediterranean sea during the early phase of the holocene a period characterised by relatively higher temperatures and lighter 18 o values has been recognised as being coeval with the climatic optimum between 10 5 and 6 1 kyr bp calendar age this interval was characterised by an abrupt drop in the pteropods relative abundances and fluxes the pteropodal fossil assemblage may have been affected by a possible event of selective dissolution of the aragonite driven by the shoaling of the acd a coeval change in the position of the pycnocline may have been responsible for a strong relative increase in abundance of neogloboquadrina pachyderma r c and a decrease in the abundance of globorotalia inflata in the western sector of the mediterranean sea

promotion of meridional overturning by mediterranean derived salt during the last deglaciation we demonstrate that changes in the behavior of the mediterranean outflow water mow prior to and through the last deglaciation played an important role in promoting meridional overturning circulation moc estimation of past mow salt and heat fluxes indicates that they gradually increased through the last deglaciation between 17 5 and 14 6 thousand years ago ka b p where b p references year 1950 net evaporation from the mediterranean exported sufficient fresh water from the north atlantic catchment to cause an average salinity increase of 0 5 psu throughout the upper 2000 m of the entire north atlantic to the north of 25

fast deformation of perennially frozen debris in a warm rock glacier in the swiss alps an effect of liquid water 1 surface movement internal deformation and temperature were monitored over 5 years on buz north rock glacier a small rock glacier located at the lower limit of the permafrost belt in the swiss alps the permafrost in the rock glacier mainly consists of pebbles and cobbles filled with interstitial ice two inclinometers installed at 4 and 5 m depths showed fast deformation with large seasonal and interannual variations while the permafrost temperatures remained almost at the melting point the movement of the inclinometers coincided with changes in the surface velocities the deformation rapidly accelerated during snowmelt periods whereas it gradually decelerated below a dry snow cover in winter the frozen debris was more deformable than typical glacier ice at the melting point these phenomena suggest that the frozen debris is permeable to snowmelt water the fast deformation should result from significant annual relocation of debris particles which probably creates a network of air voids in the frozen debris that eventually allows water infiltration the meltwater infiltration accelerates the deformation by reducing effective stress resulting in the reduced strength of the frozen debris the refreezing of the pore water which depends on the cooling intensity in winter decelerates the deformation the combination of these processes controls the temporal variations in the deformation

central mediterranean mid pleistocene paleoclimatic variability and its association with global climate abstract planktonic foraminiferal assemblages were studied at high resolution in core kc01b from the ionian sea quantitative analysis allowed us to distinguish the main climatic features and associated paleoceanographic changes that occurred between marine isotopic stages mis 13 and 9 500 300 ka mis 12 and mis 10 are characterized by relatively temperate conditions and an oligotrophic oceanographic regime in the early part and by colder conditions and nutrient supply in the sub surface water masses in the upper part during these intervals small but distinct peaks of neogloboquadrina pachyderma sinistral sin are detected at times of extremely negative values of the planktonic foraminifera paleoclimatic curve their co occurrence with similar episodes in the atlantic suggests that the climate in the central mediterranean was associated with north atlantic millennial scale climate instability mis 11 and mis 9 are dominated by surficial warm water taxa the climate optimum is reached in the middle part of each of these stages as denoted by the presence of globigerinoides sacculifer and persists for approximately 20 and 6 ka during mis 11 and mis 9 respectively this warming is not constant but is characterized by three distinct intervals with elevated winter temperatures and or weak winter mixing distribution of globigerina bulloides turborotalita quinqueloba and n pachyderma dextral dex indicates that significant environmental changes occur across the transitions from glacial to interglacial mis 12 mis 11 termination v and mis 10 mis 9 termination iv the studied record documents a close linkage between mediterranean climate evolution and higher and lower latitude climate change throughout mis 13 9

geomorphological activity at a rock glacier front detected with a 3d density based clustering algorithm abstract acquisition of high density point clouds using terrestrial laser scanners tlss has become commonplace in geomorphic science the derived point clouds are often interpolated onto regular grids and the grids compared to detect change i e erosion and deposition advancement movements this procedure is necessary for some applications e g digital terrain analysis but it inevitably leads to a certain loss of potentially valuable information contained within the point clouds in the present study an alternative methodology for geomorphological analysis and feature detection from point clouds is proposed it rests on the use of the density based spatial clustering of applications with noise dbscan applied to tls data for a rock glacier front slope in the swiss alps the proposed methods allowed the detection and isolation of movements directly from point clouds which yield to accuracies in the following computation of volumes that depend only on the actual registered distance between points we demonstrated that these values are more conservative than volumes computed with the traditional dem comparison the results are illustrated for the summer of 2015 a season of enhanced geomorphic activity associated with exceptionally high temperatures

climatic forcing of eastern mediterranean deep water formation and benthic ecosystems during the past 22 000 years abstract lateglacial and holocene faunal and stable isotope records from benthic foraminifers in the eastern mediterranean sea ems suggest a high spatiotemporal variability of deep water oxygenation and biogeochemical processes at the sea floor during that time changes in the oxygenation and food availability of the deep sea ecosystems are closely linked to the hydrology of the ems borderlands they reflect orbital and suborbital climate variations of the high northern latitudes and the african monsoon system during the last glacial maximum cool surface waters and high evaporation resulted in maximum convection and oxic deep waters in all sub basins strong wind induced mixing fostered surface water production with seasonal phytodetritus fluxes during the glacial termination and the holocene oxygenation and food availability of deep sea benthic ecosystems were characterized by a pronounced regional differentiation local deep water formation and trophic conditions were particularly variable in the northern aegean sea as a response to changes in riverine runoff and black sea outflow during the interval of sapropel s1 formation in the early holocene average oxygen levels decreased exponentially with increasing water depth suggesting a basin wide shallowing of vertical convection superimposed by local signals in the northernmost aegean sea deep water ventilation persisted during the early period of s1 formation owing to temperature driven local convection and the absence of low salinity black sea outflow at the same time severe temporary anoxia occurred in the eastern levantine basin at water depths as shallow as 900 m this area was likely influenced by enhanced nutrient input of the nile river that resulted in high organic matter fluxes and related high oxygen consumption rates in the water column in the southern aegean and levantine seas we observe a gradual increase in deep water residence times preceding s1 formation by approximately 1 1 5 kyr once oxygen levels fell below a critical threshold the benthic ecosystems collapsed almost synchronously with the onset of s1 deposition the recovery of benthic ecosystems during the terminal phase of s1 formation is controlled by subsequently deeper convection and re ventilation over a period of approximately 1500 years after the re ventilation of the various sub basins had been completed during the middle and late holocene deep water renewal was more or less similar to recent rates during that time deep sea ecosystem variability was driven by short term changes in food quantity and quality as well as in seasonality all of which are linked to millennial scale changes in riverine runoff and associated nutrient input

investigating decadal scale geomorphic dynamics in an alpine mountain setting we know little about the effect of recent climate variability upon landscapes at the timescale of decades because of 1 the complex nonlinear and path dependent nature of the response of a landscape to climate forcing and 2 the difficulty of quantifying spatially distributed impacts at the timescale of decades to centuries despite this being the timescale over which significant hypotheses have been raised over human impacts upon climate change and hence geomorphic systems a unique resource to investigate the linkages between climatic variability and geomorphic response is provided by the extensive coverage of aerial imagery commonly available since the 1950s here we use archival digital photogrammetry to produce high precision digital elevation models over large spatial scales and so to reconstruct the quantitative history of surface downwasting and sediment flux in a high mountain alpine system over the timescales of decades propagation of error methods is used to identify locations of significant landscape response and to compute volumes of significant surface change orthorectified aerial images are used in an image correlation framework to detect horizontal and vertical displacements of components of the landscape results are coupled to extant climate data and modeled snow cover to show how the landscape responds to climate forcing and to geomorphological maps to understand how this response varies between landscape elements the results show distinct landscape response to both warming and cooling periods and a tendency for the acceleration of surface displacement under warming conditions precipitation and snow cover are critical in controlling glacier dynamics and rock glacier displacement velocities however while some landforms might lead to locally high sediment flux landscape heritage can disconnect zones of high change rates from the valley bottom hence the landscape response to climate forcing is not necessarily reflected in valley system processes or sediment deposits

a rock glacier pond system nw italian alps soil and sediment properties geochemistry and trace metal bioavailability abstract rock glacier sediment transfer and ice melting can impact surface waters located downstream however there is a lack of knowledge on the influence of rock glacier dynamics on the geochemical hydrochemical and ecological characteristics of adjacent impounded surface waters in the col d olen area long term ecological research site nw italian alps an intact rock glacier terminates into a pond and solute enriched waters originating from the rock glacier flow into the pond through a subsurface hydrological window in this study we performed geophysical and ground surface temperature measurements moreover we sampled soils and sediments in different compartments of the investigated rock glacier pond system and we further sampled benthic invertebrates in the pond cold ground thermal regime ground ice presence and coarse debris cover on the rock glacier together with its lithology serpentinites influence the rock glacier geochemistry and ecology with respect to surrounding areas pond geochemistry is affected by transfer of trace metal enriched fine grained debris and meltwaters from the rock glacier enhanced bioavailability of serpentinite associated trace metals was proved with concentrations of ni and cr in benthic invertebrates up to 384 and 110 mg kg 1 d w respectively potentially exerting toxic effects on pond biota the advancing movement of the rock glacier not only has delivered sediments to the pond but it has progressively filled the valley depression where the pond is located creating a dam that could have modified the level of impounded water this process likely constituted a sediment trap in which serpentinitic rock glacier sediments could be deposited at the pond bottom with related geochemical and ecological implications this study illustrates the importance of rock glaciers in influencing the characteristics of downstream freshwater bodies and highlights the need to improve our knowledge about climate change related impacts of rock glacier dynamics on alpine headwaters