a methodology for the study of the relation between coastal cliff erosion and the mechanical strength of soils and rock masses abstract a methodology is proposed to make approximate estimates of the destructive force of waves at the bottoms of cliffs where no accurate bathymetric data are available by means of correlation between the erosion rate of rocky coasts and the mechanical strength of soils and rock masses the correlation used makes it possible to obtain a linear semi logarithmic expression between the long term average erosion rate from an engineering standpoint of coasts consisting of different lithologies wave energy and the uniaxial compressive strength of soils and rock masses forming the cliffs the uniaxial compressive strength of soils consisting of landslide debris was measured using a pocket penetrometer and the rock mass index rmi method was used for rock masses these methods were chosen after critical analysis of the methodologies currently available the proposed approach was tested in the cilento area of southern italy and in particular along a 6 km stretch of coast typified by rock masses and landslide debris that are particularly susceptible to erosion this coastline is exposed to south westerly waves which in deep water reach significant heights between 1 and 3 m and significant wave periods between 4 and 7 s estimates of the coastal erosion rates were made by studying the variations especially in restricted headland areas occurring over two time spans 30 and 45 years respectively by comparing topographic maps and aerial photographs taken at different times these comparisons give approximate indications of retreats of 15 m over the time span of 30 years average erosion rate of 0 5 m year 1 and of 35 m over the time span of 45 years average erosion rate of ca 0 8 m year 1 these data do have a local significance but clearly show how quick these processes sometimes are lastly the study of a notch incised by wave action on a concrete sea wall built to protect a terrace made it possible to quantify the impact of erosion on concrete it was possible to obtain rmi values through field observations furthermore it was possible to obtain the constants of the hoek and brown failure criterion using rmi on the basis of rmi values the rock masses studied were defined as moderately strong to strong and according to the hoek and brown criterion as poor to fair a semilogarithmic linear relation was found between the strength of landslide debris rock masses and concrete as well as their respective long term erosion consequently a rough estimate of the destructive force of waves ca 24 mpa was calculated this value is given by the product of the mean value of their hydraulic pressure for a non dimensional constant which in turn takes into account the sandy pebbly beach sediment at the foot of the cliffs that acts as an abrasive on the rock mass

microseismic measurement of wave energy delivery to a rocky coast rocky coasts are attacked by waves that drive sea cliff retreat and etch promontories and embayments into the coastline understanding the evolution of such coastlines requires knowledge of the energy supplied by waves which should depend upon both the deep water waves and the coastal bathymetry they cross we employ microseismic measurements of the wave induced shaking of sea cliffs near santa cruz california as a proxy for the temporal pattern of wave energy delivery to the coast during much of the winter 2001 storm season visual inspection of the time series suggests that both deep water wave heights and tide levels exert considerable control on the energy delivered we test this concept quantitatively with two models in which synthetic time series of wave power at the coast are compared with the shaking data in the first model deep water wave power is linearly scaled by a fitting parameter because this model fails to account for the strong tidal signal it fits poorly in the second model the wave transformation associated with shoaling and refraction diminishes the nearshore wave power and dissipation associated with bottom drag and wave breaking is parameterized by exponential dependencies on two length scales this model reduces the variance by 32 45 and captures the essence of the full signal shoaling and refraction greatly modulate the wave power delivered to the coast energy dissipated by bottom drag across the shelf is relatively small the dissipation length scale is many times the path length across the shelf in contrast much energy is dissipated in the surf zone the tidal dissipation depth scale is of the same order as the tidal range 1 2 m which accounts for the strong dependence of the cliff shaking on the tide

postdepositional losses of methane sulfonate nitrate and chloride at the european project for ice coring in antarctica deep drilling site in dronning maud land antarctica nitrate and typically 51 20 of msawere lost while for chloride no significant depletion could be observed in firn older than one year assuming a first order exponential decay rate the characteristic e folding time for msais 6 4 3 years and 19 6 years for nitrate it turns out that for nitrate and msathe typical mean concentrations representative for the last 100 years were reached after 5 4 and 6 5 years respectively indicating that beneath a depth of around 1 2 1 4 m postdepositional losses can be neglected in the area of investigation only msaconcentrations and postdepositional losses showed a distinct dependence on snow accumulation rate consequently msa concentrations archived at this site should be significantly dependent on the variability of annual snow accumulation and we recommend a corresponding correction with a simple approach we estimated the partial pressure of the free acids msa hno3 and hcl on the basis of henry s law assuming that ionic impurities of the bulk ice matrix are localized in a quasi brine layer qbl in contrast to measurements this approach predicts a nearly complete loss of msa n o3 and cl index terms 0322 atmospheric composition and structure constituent sources and sinks 0330 atmospheric composition and structure geochemical cycles 0365 atmospheric composition and structure troposphere composition and chemistry 1827 hydrology glaciology 1863 1863 hydrology snow and ice 1827 keywords postdepositional loss snow chemistry methane sulfonate

ice core reconstruction of sea ice change in the amundsen ross seas since 1702 a d antarctic sea ice has been increasing in recent decades but with strong regional differences in the expression of sea ice change declining sea ice in the bellingshausen sea since 1979 the satellite era has been linked to the observed warming on the antarctic peninsula while the ross sea sector has seen a marked increase in sea ice during this period here we present a 308 year record of methansulphonic acid from coastal west antarctica representing sea ice conditions in the amundsen ross sea we demonstrate that the recent increase in sea ice in this region is part of a longer trend with an estimated 1 northward expansion in winter sea ice extent sie during the twentieth century and a total expansion of 1 3 since 1702 the greatest reconstructed sie occurred during the mid 1990s with five of the past 30 years considered exceptional in the context of the past three centuries

nearcom tvd a quasi 3d nearshore circulation and sediment transport model article i nfo the newly developed nearshore circulation model shorecirc using a hybrid finite difference finite volume tvd type scheme is coupled with the wave model swan in the nearshore community model nearcom sys tem the new modeling system is named nearcom tvd and the purpose of this study is to report the capability and limitation of nearcom tvd for several coastal applications for tidal inlet applications the model is verified with the semi analytical solution of keulegan 1967 for an idealized inlet bay system to further evaluate the model performance in predicting nearshore circulation under intense wave current interaction over complex bathymetry modeled circulation patterns are validated with measured data during rcex field experiment macmahanetal 2010 forsedimenttransport applications two sedimenttransportmodelsare applied topre dict three sandbar migration events at duck nc during august to october 1994 gallagher et al 1998 the model of kobayashi et al 2008 incorporates wave induced onshore sediment transport rate as a function of the standard deviation of wave induced horizontal velocities the modeled beach profile evolution for two off shore events and one onshore event agrees well with the measured data the second model investigated here combines two published sediment transport models namely the total load model driven by currents under the effect of wave stirring soulsby 1997 and the wave driven sediment transport model due to wave asymmetry skewness van rijn et al 2011 the model study with limited field data suggests that the parame terization of wave stirring is appropriate during energetic wave conditions however during low energy wave conditions the effect of wave stirring needs to be re calibrated

study of a rockfall in a limy conglomerate canyon covarrubias burgos n spain in this paper a rockfall of some tenths of cubic metres of rock occurred in a conglomerate canyon in the northern castilian plateau n central spain is described in detail this includes the basic data geology mapping meteorological data and rock involved the mechanical mechanism of the instability the propagation and reach of the fallen rock boulders and the final location of the pieces the study is based on detailed geological aerial photography and geotechnical studies and advance topographical measurements geological engineering techniques are used to analyze the instability initiation and rockfall propagation this study contributes to a better understanding of the geological processes leading to the occurrence of calcareous canyons and cliffs in the drainage network of the upper castilian plateau it is also helpful to improve our knowledge on natural rockfall phenomena for risk engineering purposes aiming to quantify control and mitigate associated hazards

coastal and inland karst morphologies driven by sea level stands a gis based method for their evaluation sea level is the base level for groundwater circulation in coastal aquifers the evolution of karst surface landforms and subsurface drainage systems in these aquifers has been conditioned in geological time by tectonics and glacio eustatic sea level changes present morpho structural settings and the type distribution of karst surface and subsurface forms have developed in different carbonate formations according to differences in lithology climate and exposure time all driving the intensity of morphologic and karst processes the repeated and significant changes of groundwater level linked to sea level changes have had the most important role in driving the continuous evolution of karstic drainage systems and has resulted in most cases in a multiphase karst this study aims at defining a general method for identifying in karst coastal settings the elevations of flat or low topographic gradient surfaces using morphometric analysis of digital elevation models dems and geographical information systems giss and their comparison with elevations of distinctive karstic levels passages lateral solution cavities observed in vertical shafts and horizontal caves of the elevations of flat or low topographic gradient surfaces only those agreeing within 10 m or 20 m with elevation ranges marked by the high frequency of distinctive karst levels were considered as representative of the more probable past sea level stands the method is applied to a regional coastal carbonate formation in southern italy by using a 10 m dem and information on 140 complex caves and 85 shafts of the 15 elevations indicated by dem analysis 620 600 470 450 425 385 355 315 270 250 205 180 150 110 and 70 m above sea level a s l 13 match clearly those highlighted by significant frequencies of distinctive karstic levels these elevations are validated by comparison to the elevation of terraces and karst plains indicated in the literature copyright 2012 john wiley sons ltd

seasonality of sulfur species dimethyl sulfide sulfate and methanesulfonate in antarctica inland versus coastal regions 1 to gain a better understanding of sulfate and methanesulfonate ms signals recorded in central antarctic ice cores in terms of past atmospheric changes an atmospheric year round study of these aerosols was performed in 2006 at the concordia station 75 s 123 e located on the high antarctic plateau in addition a year round study of dimethyl sulfide dms the gaseous precursor of sulfur aerosol was conducted in 2007 the dms mixing ratio remains below 1 pptv from october to january and exhibits a maximum of 10 pptv during the first half of winter from april to july surprisingly the well marked maximum of sulfur aerosol recorded in january at coastal antarctic sites is observed at concordia for sulfate but not for ms which peaks before and after sulfate in november and march respectively this first study of dms and of its by oxidation aerosol species conducted at inland antarctica points out the complex coupling between transport and photochemistry of sulfur species over antarctica the findings highlight the complexity of the link between ms ice core records extracted at high antarctic plateau sites and dms emissions from the southern ocean

seismic precursory patterns before a cliff collapse and critical point phenomena 1 we analyse the statistical pattern of seismicity before a 1 2 103 m3 chalk cliff collapse on the normandie ocean shore western france we show that a power law acceleration of seismicity rate and energy in both 40 hz 1 5 khz and 2 hz 10khz frequency range is defined on 3 orders of magnitude within 2 hours from the collapse time simultaneously the average size of the seismic events increases toward the time to failure these in situ results are derived from the only station located within one rupture length distance from the rock fall rupture plane they mimic the critical point like behavior recovered from physical and numerical experiments before brittle failures and tertiary creep failures our analysis of this first seismic monitoring data of a cliff collapse suggests that the thermodynamic phase transition models for failure may apply for cliff collapse

concurrent correction method for modeling morphological response to dredging an offshore sandpit abstract in modeling the morphological impact of an offshore dredging pit using a process based model the hydrodynamic conditions often derived from regional scale models and sometimes incomplete measurements may not be in equilibrium with the initial bathymetry profile before dredging this lack of equilibrium causes a fast profile adjustment toward an equilibrium which may bias the model results representing the direct effect of the pit in this study a method is described which uses the parallel computing technique and evaluates only the morphological changes due to a single factor i e the dredging of a pit the hydrodynamics and morphodynamics are assumed to be in equilibrium before initial dredging of the pit the morphological evolution is computed based on the change of sediment flux due to the presence of the pit the model can avoid the computational demanding spin up period necessary to reach equilibrium conditions in particular the concurrent correction method is efficient for scenario testing with a large amount of morphological settings and hydrodynamic conditions

in situ evaluation of air sea gas exchange parameterizations using novel conservative and volatile tracers measurements of air sea gas exchange rates are reported from two deliberate tracer experiments in the southern north sea during february 1992 and 1993 a conservative tracer spores of the bacterium bacillus globigii var niger was used for the first time in an in situ air sea gas exchange experiment this nonvolatile tracer is used to correct for dispersive dilution of the volatile tracers and allows three estimations of the transfer velocity for the same time period the first estimation of the power dependence of gas transfer on molecular diffusivity in the marine environment is reported this allows the impact of bubbles on estimates of the transfer velocity derived from changes in the helium sulphur hexafluoride ratio to be assessed data from earlier dual tracer experiments are reinterpreted and findings suggest that results from all dual tracer experiments are mutually consistent the complete data set is used to test published parameterizations of gas transfer with wind speed a gas ex change relationship that shows a dependence on wind speed intermediate between those ofliss and merlivat 1986 and wanninkhof 1992 is found to be optimal the dual tracer data are shown to be reasonably consistent with global estimates of gas exchange based on the uptake of natural and bomb derived radiocarbon the degree of scatter in the data when plotted against wind speed suggests that parameters not scaling with wind speed are also influencing gas exchange rates

snow chemistry across antarctica un updated compilation of published and new data of major ion ca cl k mg na no3 so4 and methylsulfonate ms concentrations in snow from 520 antarctic sites is provided by the national itase international trans antarctic scientific expedition programmes of australia brazil china germany italy japan korea new zealand norway united kingdom the united states and the national antarctic programme of finland the comparison shows that snow chemistry concentrations vary by up to four orders of magnitude across antarctica and exhibit distinct geographical patterns the antarctic wide comparison of glaciochemical records provides a unique opportunity to improve our understanding of the fundamental factors that ultimately control the chemistry of snow or ice samples this paper aims to initiate data compilation and administration in order to provide a framework for facilitation of antarctic wide snow chemistry discussions across all itase nations and other contributing groups the data are made available through the itase web page http www2 umaine edu itase content syngroups snowchem html and will be updated with new data as they are provided in addition recommendations for future research efforts are summarized

covariation of sea ice and methanesulphonic acid in wilhelm ii land east antarctica sea ice plays an important role in ocean atmosphere heat exchange global albedo and the marine ecosystem knowledge of variation in sea ice extent is essential in order to understand past climates and to model possible future climate scenarios this paper presents results from a short firn core spanning 15 years collected from near mount brown wilhelm ii land east antarctica variations of methanesulphonic acid msa at mount brown were positively correlated with sea ice extent from the coastal region surrounding mount brown 60 1208 e and from around the entire antarctic coast 0 3608 e previous results from law dome identified this msa sea ice relationship and proposed it as an antarctic sea ice proxy curran and others 2003 with the strongest results found for the local law dome region our data provide supporting evidence for the law dome proxy at another site in east antarctica but a deeper mount brown ice core is required to confirm the sea ice decline suggested by curran and others 2003 results also indicate that this deeper record may also provide a more circum antarctic sea ice proxy

rocky coast geomorphology and erosional processes a case study along the murgia coastline south of bari apulia se italy many sites along the apulian coast se italy are composed of weathered and fractured carbonate rocks affected by intense erosion and the development of slope instabilities here coastal morphology was mostly produced by quaternary tectonics the severe and selective action of modern erosion by sea waves and locally was strongly conditioned by human influences in addition due to the carbonate nature of rock masses the role exerted by karst processes has to be considered this paper provides a critical review of the common eroding processes and factors affecting coastal morphology in a typical mediterranean coastal carbonate environment a stretch of the murgia coastline south of bari between san vito and polignano a mare made up of cliffs and shore platforms interrupted by small pocket beaches was considered for qualitative and quantitative assessment of shoreline recession the coastal stretch was monitored by means of field surveys between 1997 and 2003 furthermore a comparison of vertical aerial photographs covering the period 1966 1997 scales 1 33 000 1 10 000 and 1 5000 topographic maps scales 1 5000 year 1987 1 2000 year 1982 and archival terrestrial photographs taken since the 1930s was also employed in some zones characterised by a gently sloping shore platform a significant shoreline retreat was calculated at about 20 m in the last 100 years 0 2 myr 1 which was caused above all by human activity here in fact the presence of small ancient coastal quarries

effect of local geology on ground motion in the city of palermo italy as inferred from aftershocks of the 6 september 2002 mw 5 9 earthquake on 6 september 2002 a m w 5 9 earthquake occurred in the southern tyrrhenian sea 40 km off the coast of palermo italy in the days after the mainshock eight temporary stations were installed in the city to record aftershocks on different geological formations seismograms of about 30 earthquakes with magnitude 2 8 are analyzed the data analysis confirms the role of near surface geology in causing locally significant variations of the ground shaking level as already inferred by guidoboni et al 2003 from historical damage scenario studies the largest spectral variations estimated through aftershock recordings result in a factor of 10 difference between stiff and soft sites in frequency bands varying from 1 to 3 5 hz the geological structure of the study area is reconstructed by using data from more than 2000 boreholes organized in a geographic information system specifically dedicated to the assessment of natural hazards in urban areas vertically varying velocity models are used for a comparison with the observed data in general 1d transfer functions fit the largest amplification frequency but underestimate amplitudes of observations probably because of 2d and 3d complexity because the seismic stations were not installed in free field but at ground or underground level inside buildings a possible influence of the structure was also investigated simultaneous ambient noise measurements were performed on the top at the base and outside the buildings where stations were installed for all but one site this analysis shows that the estimated ground motion amplifications do not reflect the building vibration modes and therefore in these cases soil structure interaction does not bias the free field response of the study sites finally speculations on the effect of the local geology in terms of response spectra of the m w 5 9 mainshock are discussed in the framework of the eurocode 8 prescriptions

ice core evidence for antarctic sea ice decline since the 1950s the instrumental record of antarctic sea ice in recent decades does not reveal a clear signature of warming despite observational evidence from coastal antarctica here we report a significant correlation p

marine aerosol source regions to prince of wales icefield ellesmere island and influence from the tropical pacific 1979 2001 using a coastal ice core collected from prince of wales pow icefield on ellesmere island we investigate source regions of sea ice modulated chemical species methanesulfonic acid msa and chloride cl to pow icefield and the influence of large scale atmospheric variability on the transport of these marine aerosols 1979 2001 our key findings are 1 msa in the pow icefield core is derived primarily from productivity in the sea ice zone of baffin bay and the labrador sea with influence from waters within the north water now polynya 2 sea ice formation processes within the now polynya may be a significant source of sea salt aerosols to the pow core site in addition to offshore open water source regions primarily in hudson bay and 3 the tropical pacific influences the source and transport of marine aerosols to pow icefield through its remote control on regional winds and sea ice variability regression analyses during times of msa deposition reveal sea level pressure slp anomalies favorable for opening of the now polynya and subsequent oceanic dimethyl sulfide production regression analyses during times of cl deposition reveal slp anomalies that indicate a broader oceanic region of sea salt sources to the core site these results are supported by scanning multichannel microwave radiometer and special sensor microwave imager based sea ice reconstructions and air mass transport density analyses and suggest that the marine biogenic record may capture local polynya variability while sea salt transport to the site from larger offshore source regions in baffin bay is likely regression analyses show a link to tropical dynamics via an atmospheric rossby wave

methanesulfonic acid in south polar snow layers a record of strong el nino in this paper we present a detailed study of methanesulfonic acid msa and non sea salt sulfate nss so4 content in recent south polar precipitation these two species are major oxidation products of dimethylsulfide dms which is mainly produced by marine biota the nss so4 content of south polar snow layers deposited over the 1922 1984 time period remained rather stable except short term increases after the mt agung 1963 and the el chichon 1982 eruptions at the opposite the msa profile shows over the same time period several sporadic 0 5 to 2 years increases 2 to 10 times background level taking into account an uncertainty of 1 3 years in the dating of snow layers all these msa events seem to be correlated to major enso el nino southern oscillation events having occured over the last sixty years 1925 26 1941 1957 58 1972 73 and 1982 83 the relatively high msa nssso4 weight ratios r observed in the corresponding snow layers suggest that these events reflect enhanced dms emissions from the antarctic ocean this suggested connection between enso and high dms marine emissions at high southern latitudes is discussed in terms of atmospheric and oceanic circulation

dynamic response of a rocky cliff under the sea wave pulse a study along the adriatic coast of polignano apulia italy the dynamic behavior of a rocky cliff under severe sea waves has been analyzed in the location of polignano facing on the adriatic coast of apulia southern italy in this area the classical and at the same time complex problem of the stability of a cliff in calcareous rocks is burdened by the presence on the top of the cliff of the ancient town to analyze the behavior of the cliff under the impulsive transfer of energy generated by the sea waves two types of measures were carried out on the rocky mass 1 ambient noise and 2 strong motion records the first type of measures which may be executed in a short time with a high spatial density has provided a recognition of the intrinsic and anisotropic dynamic behavior of the coastal cliff the accelerometric records carried out during heavy storms in december 2009 and january 2010 allowed to evaluate the energy transfer from waves to cliff in terms of maximum values and temporal and directional distribution to facilitate a correct interpretation of the measures also a geomechanical characterization of the rocky mass has been carried out through the rock mass rating system bieniawski the geomechanics classification in rock engineering applications proceedings of the 4th isrm cong montreux pp 51 58 1979 bieniawski engineering rock mass classifications wiley new york p 251 1989 and the markland s test a useful technique for estimating the stability of rock slopes when the rigid wedge sliding type of failure is expected pp 10 1972 the first allowed to classify the rocky masses in terms of quality the second one to individuate the potential failure mechanisms of the cliff

state of the antarctic and southern ocean climate system this paper reviews developments in our understanding of the state of the antarctic and southern ocean climate and its relation to the global climate system over the last few millennia climate over this and earlier periods has not been stable as evidenced by the occurrence of abrupt changes in atmospheric circulation and temperature recorded in antarctic ice core proxies for past climate two of the most prominent abrupt climate change events are characterized by intensification of the circumpolar westerlies also known as the southern annular mode between 6000 and 5000 years ago and since 1200 1000 years ago following the last of these is a period of major trans antarctic reorganization of atmospheric circulation and temperature between ad1700 and 1850 the two earlier antarctic abrupt climate change events appear linked to but predate by several centuries even more abrupt climate change in the north atlantic and the end of the more recent event is coincident with reorganization of atmospheric circulation in the north pacific improved understanding of such events and of the associations between abrupt climate change events recorded in both hemispheres is critical to predicting the impact and timing of future abrupt climate change events potentially forced by anthropogenic changes in greenhouse gases and aerosols special attention is given to the climate of the past 200 years which was recorded by a network of recently available shallow firn cores and to that of the past 50 years which was monitored by the continuous instrumental record significant regional climate changes have taken place in the antarctic during the past 50 years atmospheric temperatures have increased markedly over the antarctic peninsula linked to nearby ocean warming and intensification of the circumpolar westerlies glaciers are retreating on the peninsula in patagonia on the sub antarctic islands and in west antarctica adjacent to the peninsula the penetration of marine air masses has become more pronounced over parts of west antarctica above the surface the antarctic troposphere has warmed during winter while the stratosphere has cooled year round the upper kilometer of the circumpolar southern ocean has warmed antarctic bottom water across a wide sector off east antarctica has freshened and the densest bottom water in the weddell sea has warmed in contrast to these regional climate changes over most of antarctica near surface temperature and snowfall have not increased significantly during at least the past 50 years and proxy data suggest that the atmospheric circulation over the interior has remained in a similar state for at least the past 200 years furthermore the total sea ice cover around antarctica has exhibited no significant overall change since reliable satellite monitoring began in the late 1970s despite large but compensating regional changes the inhomogeneity of antarctic climate in space and time implies that recent antarctic climate changes are due on the one hand to a combination of strong multi decadal variability and anthropogenic effects and as demonstrated by the paleoclimate record on the other hand to multi decadal to millennial scale and longer natural variability forced through changes in orbital insolation greenhouse gases solar variability ice dynamics and aerosols model projections suggest that over the 21st century the antarctic interior will warm by 3 4 1oc and sea ice extent will decrease by 30 ice sheet models are not yet adequate enough to answer pressing questions about the effect of projected warming on mass balance and sea level considering the potentially major impacts of a warming climate on antarctica vigorous efforts are needed to better understand all aspects of the highly coupled antarctic climate system as well as its influence on the earth s climate and oceans

sulfur cycle at last glacial maximum model results versus antarctic ice core data for the first time an atmospheric general circulation and sulfur chemistry model is used to simulate sulfur deposition in antarctica at the last glacial maximum lgm dimethylsulfide dms emitted by phytoplankton is the dominant source of atmospheric sulfur in antarctica once in the atmosphere it is oxidized into sulfur aerosols which are measured in ice cores such measurements allow for validating climate and chemistry models for glacial interglacial changes our glacial simulations test the effect of a recent re evaluation of glacial sea ice coverage on dms sources and sulfur aerosol deposition using the present day oceanic concentrations of dms the model reproduces observed glacial and interglacial sulfur concentrations in the ice this result suggests that climate change at the lgm did not greatly impact on dms production in the oceanic sectors where sulfur aerosols deposited in central east antarctica originate from

ice core records as sea ice proxies an evaluation from the weddell sea region of antarctica 1 ice core records of methanesulfonic acid msa from three sites around the weddell sea are investigated for their potential as sea ice proxies it is found that the amount of msa reaching the ice core sites decreases following years of increased winter sea ice in the weddell sea opposite to the expected relationship if msa is to be used as a sea ice proxy it is also shown that this negative msa sea ice relationship cannot be explained by the influence that the extensive summer ice pack in the weddell sea has on msa production area and transport distance a historical record of sea ice from the northern weddell sea shows that the negative relationship between msa and winter sea ice exists over interannual 7 year period and multidecadal 20 year period timescales national centers for environmental prediction national center for atmospheric research ncep ncar reanalysis data suggest that this negative relationship is most likely due to variations in the strength of cold offshore wind anomalies traveling across the weddell sea which act to synergistically increase sea ice extent sie while decreasing msa delivery to the ice core sites hence our findings show that in some locations atmospheric transport strength rather than sea ice conditions is the dominant factor that determines the msa signal preserved in near coastal ice cores a cautious approach is thus required in using ice core msa for reconstructing past sea ice conditions including the need for networks of ice core records and multiproxy studies to assess the significance of past msa changes at different locations around antarctica

ice sheet record of recent sea ice behavior and polynya variability in the amundsen sea west antarctica investigation of how regional sic is recorded in the ice sheet stratigraphy over the period 2002 2010 we find that the ice sheet chemistry is significantly correlated with sic variability within the as and pine island bay polynyas based on this result we evaluate the use of icecore chemistry as a proxy for interannual polynya variability in this region one of the largest and most persistent polynya areas in antarctica msa concentrations correlate strongly with summer sic within the polynya regions consistent with msa at this site being derived from marine biological productivity during the spring and summer cl concentrations correlate strongly with winter sic within the polynyas as well as some regions outside the polynyas consistent with cl at this site originating primarily from winter sea ice formation spatial correlations were generally insignificant outside of the polynya areas with some notable exceptions ice core glaciochemical records from this dynamic region thus may provide a proxy for reconstructing as and pine island bay polynya variability prior to the satellite era

sea saltwater weakening of chalk and the impact on cliff instability chalk forms one of the major coastal cliff formations throughout northwest europe with large population centres and critical infrastructure being exposed to and at risk from cliff collapses in this rock type traditionally the two main factors leading to chalk cliff collapse have been considered to be i waves attacking and eroding the base of the cliff and ii water weakening as the chalk becomes saturated this work challenges the established view by identifying the role of salt from seawater in the degradation of porous rocks in coastal environments as a third and potentially the most important mechanism leading to chalk cliff collapse field and laboratory investigations have identified and quantified the role of sea saltwater weakening of chalk in coastal environments a series of triaxial strength tests have identified that coastal chalks are up to 55 weaker than their inland equivalents this weakening process is as a result of saltwater ingress into the chalk sem imaging has shown that seawater penetrates the porous chalk and the salt progressively concentrates forming salt crystals which disrupt the pore structure and weakening the rock material which then leads to catastrophic cliff failure saltwater weakening of cliffs could be one of the main factors leading to large and small scale collapses observed along the chalk coast line and is likely to be the primary reason for the increasing frequency of cliff failures along protected coastal sections as the sea salt progressively concentrates in the cliff reducing its mechanical strength rock strength is not usually considered to be temporally variable and is therefore rarely considered in relation to climate change however this is not true of soft rocks like chalk which weaken and collapse in short time periods as they are exposed to external factors

a review of sea ice proxy information from polar ice cores sea ice plays an important role in earth s climate system the lack of direct indications of past sea ice coverage however means that there is limited knowledge of the sensitivity and rate at which sea ice dynamics are involved in amplifying climate changes as such there is a need to develop new proxy records for reconstructing past sea ice conditions here we review the advances that have been made in using chemical tracers preserved in ice cores to determine past changes in sea ice cover around antarctica ice core records of sea salt concentration show promise for revealing patterns of sea ice extent particularly over glacial interglacial time scales in the coldest climates however the sea salt signal appears to lose sensitivity and further work is required to determine how this proxy can be developed into a quantitative sea ice indicator methane sulphonic acid msa in near coastal ice cores has been used to reconstruct quantified changes and interannual variability in sea ice extent over shorter time scales spanning the last 160 years and has potential to be extended to produce records of antarctic sea ice changes throughout the holocene however the msa ice core proxy also requires careful site assessment and interpretation alongside other palaeoclimate indicators to ensure reconstructions are not biased by non sea ice factors and we summarise some recommended strategies for the further development of sea ice histories from ice core msa for both proxies the limited information about the production and transfer of chemical markers from the sea ice zone to the antarctic ice sheets remains an issue that requires further multidisciplinary study despite some exploratory and statistical work the application of either proxy as an indicator of sea ice change in the arctic also remains largely unknown as information about these new ice core proxies builds so too does the potential to develop a more comprehensive understanding of past changes in sea ice and its role in both long and short term climate changes

a 340 year record of biogenic sulphur from the weddell sea area antarctica detailed records of methanesulphonic acid msa and non sea salt sulpha te nss so have been obtained from ice cores drilled on dolleman island on the east coast of the antarctic peninsula i0 35 2 s 60 55 5 w annual average concentrations of msa arc presented for the period i 652 1992 over this lime span the mean ann ual concen tration of msa is 0 69 eq 1 1 cr 0 33 n 340 the range is 0 13 2 35 eq 1 1 a nd the msa nss s04 2 ratio is 0 22 the high msa concentration reflects the proximity of the weddell sea believed to be a region of high marine phyt0plankton production t he overa ll mean nss so concentration is about 66 of the total sulphate d eposited in the snowfall low frequency variations of msa and oxygen isolope signals correla te closely indicat ing that they may be modulated by similar atmospheric processes positive correlations are observed between the oxygenisotope signature and both l 1sa r 0 4 1 and nss s04 2 r 0 50 signilicant at the 99 level a small negative correlation can be seen between both species and the annual duration or sea ice a t scoria bay laurie island in the south orkneys since 1902 msa r 0 23 and nss so r 0 29 significant at 95 confidence no significant link between high msa concentrations and el nino even ts is observed at this location

hydrodynamic and sediment transport modeling of new river inlet nc under the interaction of tides and waves the interactions between waves tidal currents and bathymetry near new river inlet nc usa are investigated to understand the effects on the resulting hydrodynamics and sediment transport a quasi 3 d nearshore community model nearcom tvd is used in this integrated observational and modeling study the model is validated with observations of waves and currents at 30 locations including in a recently dredged navigation channel and a shallower channel and on the ebb tidal delta for a range of flow and offshore wave conditions during may 2012 in the channels model skills for flow velocity and wave height are high near the ebb tidal delta the model reproduces the observed rapid onshore offshore decay of wave heights current velocities model results reveal that this sharp transition coincides with the location of the breaker zone over the ebb tidal delta which is modulated by semidiurnal tides and by wave intensity the modulation of wave heights is primarily owing to depth changes rather than direct wave current interaction the modeled tidally averaged residual flow patterns show that waves play an important role in generating vortices and landward directed currents near the inlet entrance numerical experiments suggest that these flow patterns are associated with the channel shoal bathymetry near the inlet similar to the generation of rip currents consistent with other inlet studies model results suggest that tidal currents drive sediment fluxes in the channels but that sediment fluxes on the ebb tidal delta are driven primarily by waves

tropical pacific influence on the source and transport of marine aerosols to west antarctica abstractthe climate of west antarctica is strongly influenced by remote forcing from the tropical pacific for example recent surface warming over west antarctica reflects atmospheric circulation changes over the amundsen sea driven by an atmospheric rossby wave response to tropical sea surface temperature sst anomalies here it is demonstrated that tropical pacific sst anomalies also influence the source and transport of marine derived aerosols to the west antarctic ice sheet using records from four firn cores collected along the amundsen coast of west antarctica the relationship between sea ice modulated chemical species and large scale atmospheric variability in the tropical pacific from 1979 to 2010 is investigated significant correlations are found between marine biogenic aerosols and sea salts and sst and sea level pressure in the tropical pacific in particular la nina like conditions generate an atmospheric rossby wave response that influences atmospheric circulation over pine island bay

modeled methanesulfonic acid msa deposition in antarctica and its relationship to sea ice 1 methanesulfonic acid msa has previously been measured in ice cores in antarctica as a proxy for sea ice extent and southern hemisphere circulation in a series of chemical transport model geos chem sensitivity experiments we identify mechanisms that control the msa concentrations recorded in ice cores sea ice is linked to msa via dimethylsulfide dms which is produced biologically in the surface ocean and known to be particularly concentrated in the sea ice zone given existing ocean surface dms concentration data sets the model does not demonstrate a strong relationship between sea ice and msa deposition in antarctica the variability of dms emissions associated with sea ice extent is small 11 30 due to the small interannual variability of sea ice extent wind plays a role in the variability in dms emissions but its contribution relative to that of sea ice is strongly dependent on the assumed dms concentrations in the sea ice zone atmospheric sulfur emitted as dms from the sea ice undergoes net transport northward our model runs suggest that dms emissions from the sea ice zone may account for 26 62 of msa deposition at the antarctic coast and 36 95 in inland antarctica though our results are sensitive to model assumptions it is clear that an improved understanding of both dms concentrations and emissions from the sea ice zone are required to better assess the impact of sea ice variability on msa deposition to antarctica

preliminary assessments on the modes of instability of the antalya sw turkey coastal cliffs cliff erosion and the consequent instabilities present a significant risk to antalya city sw turkey erosional processes include the chemical action of mixing zone water the mechanical action of waves salt erosion and biological degradation the rock properties lithology stratification strength etc are the controlling factors to this erosion the coastal cliffs of antalya are composed of tufa type carbonate rocks which occur in a wide range from collapsible soil to hard rock the instability problems of the cliffs of antalya tufa commonly involve rock fall cave collapse raveling washout of weakly lithified tufa shear failure and secondary toppling secondary toppling type instabilities culmann type failures and complex failures a combination of these two are widespread on the cliffs the occurrence of large failures are usually associated with heavy rainfall as heavy rainfall causes the saturation of pores increases pore water pressures and reduces the strength of the rock comparison between aerial photographs and topographic maps of different dates do not provide evidence of considerable retreat according to the historical data there has been little or no cliff retreat for 2 000 years therefore the erosion rate of the antalya tufa cliffs is said to be so very slow that retreat is valid only in a geological timescale however in an engineering timescale these cliffs are subjected to instabilities and to local failures causing local retreats

physical properties and textural parameters of calcarenitic rocks qualitative and quantitative evaluations abstract petrophysical and mechanical properties of sedimentary rocks are influenced by size shape and packing of grains porosity cement and matrix content all controlled strongly by depositional fabric and postdepositional processes this paper presents a study on the textural characteristics of soft and porous calcarenites and the main methods to determine petrophysical data the examined calcarenites sampled from three quarry districts located in apulia southeastern italy are fine grained and coarse grained grainstones a and d and medium grained packstones b belonging to a plio pleistocenic formation calcarenite di gravina outcropping in the whole region the study involved particularly textural analysis on thin sections using optical petrographic microscopy and evaluation of total and effective porosity by means of standard geotechnical laboratory tests mercury intrusion porosimetry and image analysis grain size frequency distribution was also carried out by traditional sieve and sedimentation analysis on disaggregated materials and image analysis computer analysis of digital images was performed on photomicrographs applying the methods of quantitative stereology to pore size and grain size distributions a comparison between results showed that each technique used has its limitations linked to the textural characteristics primarily geometry and topology of the pore network granulometry grain shape and packing of calcarenites

impacts of wave energy and littoral currents on shoreline erosion accretion along the south west coast of kanyakumari tamil nadu using dsas and geospatial technology the present study investigates the impact of wave energy and littoral current on shorelines along the south west coast of kanyakumari tamil nadu india the multi temporal landsat tm etm images acquired from 1999 to 2011 were used to demarcate the rate of shoreline shift using gis based digital shoreline analysis system the statistical analysis such as net shoreline movement and end point rate were determined from the multi temporal shoreline layers moreover the wave energy and seasonal littoral current velocity were calculated for each coastal zone using mathematical equations the results reveal that the coastal zones which include kanyakumari kovalam manavalakurichi and thengapattinam coasts consisting of maximum wave energy along with high velocity of littoral current have faced continuous erosion processes the estimated wave energy along these zones ranges from 6 5 to 8 5 kj km2 and the observed current velocity varies from 0 22 to 0 32 m s during south west and north east monsoons the cumulative effect of these coastal processes in the study area leads to severe erosion that is estimated as 300 63 69 92 54 12 and 66 11 m respectively however the coastal zones namely rajakkamangalam ganapathipuram muttam and colachel have experienced sediment deposits due to current movement during the north east monsoon however the trend changes during the south west monsoon as a result of sediment drift through backwash the spatial variation of shoreline and its impact on wave energy and the littoral current have been mapped using the geo spatial technology this study envisages the impact of coastal processes on site specific shorelines hence the study will be effective for sustainable coastal zone management

dimethylsulphide and dimethylsulphoniopropionate in the south west indian ocean sector of east antarctica from 30 to 80 e during broke west abstract we investigated the spatial and vertical variations of dimethylsulphide dms dissolved particulate and total dimethylsulphoniopropionate dmspd dmspp and dmspt in the south west indian ocean sector of east antarctica between 30 80 e and south of 62 s from january to march 2006 twenty seven sites were examined and mean concentrations in the upper 150 m of the water column were for dms 8 nm range nd 63 nm dmspd 5 nm nd 36 nm dmspp 11 nm nd 38 nm and dmspt 16 nm nd 54 nm the highest concentrations of the sulphur compounds occurred in the western sector of the study area on the antarctic shelf and across the antarctic slope front region asf of the eastern weddell gyre ewg in the cosmonaut sea concentrations were lower north of the asf region of the ewg and in the eastern sector of the antarctic circumpolar current acc and the greater prydz bay gyre pbg circulation in the cooperation sea the influence of melting pack ice on dms and dmspd concentrations was apparent in this study but was predominantly restricted to a few stations in the cosmonaut sea early in the voyage dms concentrations were extremely high at stations in the western sector of the marginal ice zone miz in the early part of the study mean 25 nm reaching concentrations as high as 63 nm at station 42 decreasing to a mean concentration of 5 5 nm in the reduced miz to the east in the seasonal mixed layer sml water 4 50 m from the acc and ewg mean dms concentrations were 5 nm whilst very low concentrations of dms occurred under forming sea ice 0 5 nm mean dmspp concentrations in the top 50 m of the miz stations across the survey were closely similar 18 20 nm and slightly higher than sml waters 13 14 nm whilst mean dmspd concentrations were 275 and 100 higher in samples from the miz stations 8 15 nm compared with sml waters 4 nm in the eastern sector the coastal region across the shelf break and asf region was largely free of ice and there was generally no elevation of dmspd mean 4 nm this suggests that biological processes associated with the pack or fast ice in the asf region of the western sector of the survey in conjunction with the oceanography of the region may have caused the high concentrations of dms and dmspd observed at latitudes 67 s whilst filtration affects did influence dmspd concentrations at a few sites it was clear that elevated dms and dmspd concentrations occurred in the top 50 m and winter water ww layers of miz stations and in high salinity shelf water hssw at specific locations on the antarctic shelf and likely reflected melting sea ice dms and dmspp were also detected below the euphotic zone in modified circumpolar deep water mcdw on the antarctic slope with dmspp possibly transported there in sedimenting detritus and faecal material the significant concentrations of dms detected in lower mcdw 0 42 1 1 nm and antarctic bottom water aabw 2 7 nm were likely to have been transported to these depths in wintertime as dense shelf water overflows from the cape darnley and prydz bay source regions the high concentrations of dms and dmspd observed in the surface waters of the miz further support the importance of the antarctic region and the sea ice zone to the global sulphur cycle

methodological study of submarine groundwater discharge from a karstic aquifer in the western mediterranean sea summary a multiproxy approach of complementary techniques is applied to localise and quantify submarine groundwater discharge sgd from el maestrazgo jurassic aquifer an example of widespread carbonate coastal aquifer of the western mediterranean sea castellon spain unconventional water resources are critical in this area where highly populated resorts have been developed the aquifer has two main features of particular interest a karstic system with a deep saturated zone reaching 450 m and with no significant surface discharge occurring within the continental area on the other hand sgd can alter the condition of coastal marine environments reducing salinities and providing nutrients that can cause eutrophication and algal blooms the applied combined techniques make it possible to detect groundwater outflows using airborne thermal infrared tir images to monitor physico chemical anomalies in the sea and to quantify the submarine groundwater discharges by means of direct measurements and radium isotopic analyses three main coastal areas affected by sgd and a submarine spring located at 3 km from the coast which seems to be associated with tectonic discontinuities were localised the calculated fresh sgd from ra isotopes 375 mm 3 y 1 is in agreement with the mean aquifer recharge obtained by hydrogeological methods 394 mm 3 y 1

influence of large scale teleconnection patterns on methane sulfonate ice core records in dronning maud land records of methane sulfonate ms in ice cores from the high plateau of dronningmaud land dml antarctica drilled in the framework of the european project for icecoring in antarctica are investigated for their potential as an environmental andclimate archive for the atlantic sector of the southern ocean despite postdepositionalchanges years of extraordinary ms concentrations can be clearly detected in the icecore records we use composite anomaly maps of atmospheric parameters from thenational centers for environmental prediction national center for atmospheric researchreanalysis fields for years of extreme ms concentration to detect atmospheric patternscausing ms variability changing atmospheric transport is shown to be an important but not exclusive parameter being conserved in the ms record in dml the oftenhypothesized direct link between high ms concentrations and el nino events is notsupported for the observed region whereas the antarctic dipole adp which ismodulated by el nino southern oscillation conditions exerts significant influence aclear 13 9 year cycle can be found throughout a 2000 year ms record that can be relatedto variations in the adp over the last 300 years a 4 6 year cycle is revealed in thems and sea salt record which vanishes in the deeper part of the ice core as aconsequence of diffusion processes from the long term perspective periods of high msconcentrations are connected to on average higher sea salt aerosol as well reflecting aseasonally independent influence of transport on both species a distinctive period ofefficient atmospheric transport probably due to a pronounced adp could be foundfrom 1200 to 1600 a d