correcting the cenozoic δ18o deep sea temperature record for antarctic ice volume abstract the oxygen isotope signal in benthic foraminifera from deep sea cores is mainly determined by deep ocean temperature and land ice volume separating the temperature and ice volume signals is a key step in understanding the evolution of cenozoic climate except for the last few million years fluctuations in land ice volume were determined mainly by the size of the antarctic ice sheet here a simplified antarctic ice sheet model and composite deep sea oxygen isotope records are used to derive a deep sea temperature history for the cenozoic the ice sheet model is forced with the oxygen isotope record which is instantaneously corrected for the calculated ice volume therefore the resulting deep sea temperature and antarctic ice volume curves are mutually consistent the temperature record of lear et al science 287 2000 269 derived from the mg ca ratio in benthic calcite is also used to force the ice sheet model the resulting ice volume does not agree well with the ice volume history inferred by lear et al from a comparison of mg ca and 18 o records the most important points emerging from this study are the cenozoic 18 o record from benthic forams is a truly mixed signal ice volume and deep sea temperature contribute equally to the variance for the period of 45 to 30 ma ago 18 o temperatures are significantly lower than mg ca temperatures rapid nonlinear build up of a continental scale ice sheet on the antarctic continent can easily occur for a linear cooling rate it is unlikely that the method of lear et al provides a reliable measure of ice volume the cooling rate at the beginning of the pliocene is much larger in the 18 o temperature curves than in the mg ca temperature curve

quantitative assessment of in situ salt karstification using shear wave velocity dead sea abstract the dead sea ds coastal areas have been dramatically affected by sinkhole formation since around 1990 such sinkholes along both israeli and jordanian shores are linked to karst cavities that form through slow salt dissolution a quantitative estimate of such in situ salt karstification would be an important indicator of sinkhole hazard one of the indications of salt karstification is its increased hydraulic conductivity caused by the development of dissolution cavities forming conducting channels within the salt layer we measured the hydraulic conductivity k versus shear wave velocity vs of ds salt in situ for estimating the actual salt karstification in areas of sinkhole development these parameters were measured with the magnetic resonance sounding mrs and multichannel analysis of surface waves masw methods respectively understanding of the field relationships was augmented by similar inter relations obtained in the laboratory on samples of ds salt in situ salt velocities vs vary from 750 m s to over 1650 m s while hydraulic conductivity k in the same zones varies between about 10 4 m s to slightly over 10 8 m s both field and laboratory k and vs values fit the exponential function ln k 0 0045 vs 5 416 with a determination coefficient r2 of 0 88 a classification based on vs and k was generated for salt conditions and the corresponding degrees of sinkhole hazard which was verified in the mineral beach sinkhole development area the mapping of sinkhole sites shows that they form within highly conductive zones with k 5 5 10 5 it is suggested that this methodology with some modification can be used for evaluating the conductive properties of karstified rock and associated sinkhole hazards

quasi 2d block inversion of large scale surface nuclear magnetic resonance profile data using a laterally constrained model abstractthe water content of underground structures can be imaged using surface nuclear magnetic resonance nmr in one dimension two dimensions or recently three dimensions the maximum efficiency can be obtained with a coincident loop configuration in a large scale area although the resolution is limited we have developed a quasi 2d block inversion to characterize a horizontal continuous underground aquifer using a laterally constrained model to improve the resolution of thin aquifers and deep aquifers through the simulation of flat surface and irregular surface models a horizontally layered aquifer with continuously variable water content and t2 can be imaged through quasi 2d block inversion which is more optimized than the traditional 1d block or 1d or 2d smooth inversion methods finally using a series of profile data obtained from surface nmr field measurements in mongolia we determine that quasi 2d block inversion based on a laterally constrained model can significantly improve the disco

spatial expression of enso drought and summer monsoon in seasonal δ13c of ponderosa pine tree rings in southern arizona and new mexico 1 major climatic impacts from enso and the north american monsoon in the u s southwest provide fortuitous circumstances for exploring the suitability of stable carbon isotope 13c composition of tree rings to represent and reconstruct interannual climate variability we sampled ponderosa pine tree rings at eight sites in seven mountain ranges over a 500 km transect in southern arizona and new mexico we developed 13c chronologies for 1985 1995 by subdividing rings into pre and post monsoon onset segments based on the presence of a false latewood band in each ring induced by the arid period immediately preceding the summer monsoon pooling these segments from multiple trees at each site and analyzing the cellulose component chronologies from two subsets of trees from the same site and separate chronologies from two different sites in the same mountain range indicate strong coherence and signal reproducibility additionally the seasonal 13c patterns showed remarkable coherence across the transect with the spatially disjunct easternmost chronology tending to be most frequently dissimilar the 13c values of ring subdivisions before the false latewood band are generally positively correlated with winter southern oscillation indices soi resulting from the enso teleconnection with southwestern winter early spring precipitation the 13c from these sites correlates with monthly palmer drought severity indices pdsi with the strongest correlations occurring in progressively later months from first formed to last formed subdivisions the post false latewood subdivision 13c was particularly strongly correlated with summer precipitation amount these results confirm the strong influence of moisture on tree ring 13c and support their use in both temporal and spatial modes to infer past climate variability

the pacific decadal oscillation air sea interaction and central north pacific winter atmospheric regimes prominent and persistent anomalies in the atmospheric flow troughs and ridges occur sporadically over the central north pacific and can have profound consequences for the weather of north america we have examined how these events are associated with large scale central north pacific sea surface temperature sst anomalies using an index for the pacific decadal oscillation pdo the anomalies in turbulent air sea heat fluxes and low level baroclinity associated with the pdo are manifested differently during troughs than during ridges in their effects on the transient eddies storms these effects may help explain why prominent troughs ridges occur about 3 2 5 times more frequently during periods when the pdo is significantly positive negative than of opposite sign our results suggest that the state of the mid latitude pacific ocean more fundamentally affects the atmosphere than has been thought

the modeled atmospheric response to midlatitude sst anomalies and its dependence on background circulation states abstract the atmospheric response to a midlatitude sst anomaly in the north pacific and its dependence on background flow are examined in a gcm experiments are conducted using the same warm sst anomalies but two different model states perpetual january and perpetual february the atmospheric responses to the sst anomalies are statistically significant in both january and february but are completely different the anomalous circulation in january is characterized by a trough decaying with height immediately downstream of the sst anomalies in february the anomalous circulation is dominated by a downstream ridge growing with height the patterns of the anomalous heights in the two months are nearly orthogonal vorticity and thermodynamic budgets are diagnosed to illustrate how the anomalous circulations are maintained over the sst anomalies low level convergence and ascent are observed in both months in january the anomalous convergence is balanced by a residual due primarily to the forcing by submont

locating water filled karst caverns and estimating their volume using magnetic resonance soundings magnetic resonance sounding mrs is a geophysical technique developed for groundwater exploration this technique can be used for investigating karst aquifers generally the study ofakarstrequiresa3dfieldsetupandcorrespondingmultichannel data acquisition instruments now only single channel mrs equipment is available i e the time needed for a 3d mrs field survey is multiplied by a factor of four or five where karst caverns are natural hazards as in the dead sea coastal area at nahal hever israel even an approximate localization of potentially dangerous zones and a corresponding estimation of the hazard dimensions are useful we studied numerically the accuracy of mrs estimations of the volume of different 3d targets around nahalhever shiftinga3dtargetinsidethemrsloopandcalculating the volume estimation errors for each target position the calculations covered targets of different sizes the size and position of a target being unknown factors in a field survey the numerical data were considered as random values to be analyzed statistically using a 1d approximation of the mrs solution and assuming a 100 100 m 2 mrs loop the volume of a 3d target under nahal hever conditions is estimated within a 75 error when the target is smaller than the mrs loop and within a 50 error when the target size is about the same as the mrs loop the lower threshold of karst cavity detection with mrs is about 6500 m3 for such estimation only one sounding is

multispectral imaging contributions to global land ice measurements from space global land ice measurements from space glims is an international consortium established to acquire satellite images of the world s glaciers analyse them for glacier extent and changes and assess change data for causes and implications for people and the environment although glims is making use of multiple remote sensing systems aster advanced spaceborne thermal emission and reflection radiometer is optimized for many needed observations including mapping of glacier boundaries and material facies and tracking of surface dynamics such as flow vector fields and supraglacial lake development software development by glims is geared toward mapping clean ice and debris covered glaciers terrain classification emphasizing snow ice water and admixtures of ice with rock debris multitemporal change analysis visualization of images and derived data and interpretation and archiving of derived data a global glacier database has been designed at the national snow and ice data center nsidc boulder colorado parameters are compatible with and expanded from those of the world glacier inventory wgi these technology efforts are summarized here but will be presented in detail elsewhere our presentation here pertains to one broad question how can aster and other satellite multispectral data be used to map monitor and characterize the state and dynamics of glaciers and to understand their responses to 20th and 21st century climate change our sampled results are not yet glaciologically or climatically representative our early results while indicating complexity are generally consistent with the glaciology community s conclusion that climate change is spurring glacier responses around the world mainly retreat whether individual glaciers are advancing or retreating the aggregate average of glacier change must be climatic in origin as nonclimatic variations average out we have discerned regional spatial patterns in glaciological response behavior these patterns are best attributed to climate change variability and to regional differences in glacier size and response times in many cases glacier length changes under represent the magnitude of glacier ablation because thinning sometimes without immediate length changes is also important an expanded systematic uniform analysis of many more glaciers is needed to isolate the glacier response components due to climatic and nonclimatic perturbations to produce quantitative measures of regional variation in glacier changes and to predict future regional glacier trends relevant to water resources glaciological hazards and global sea level this comprehensive assessment to be completed in stages is expected to lend a critically needed filter to identify successful climate models that explain recent glacier changes and change patterns and hence are apt to describe future changes and to eliminate unsuccessful models

a comparison of em induction and gpr methods in areas of karst abstract electromagnetic em induction and ground penetrating radar gpr methods have been used extensively in areas of karst to detect and delineate major structural and solution features and to improve site assessments these methods do not work equally well in all soils and the amount of practical information derived from surveys has varied the choice of the most appropriate method often depends on the electrical properties of the soils this study characterized the use of gpr and em at two contrasting sites in florida and pennsylvania the florida site is underlain by relatively thick layers of electrically resistive sands overlying loamy marine sediments and limestone bedrock gpr was effectively used to determine the thickness of surface layers and the locations of buried solution features multiple contrasting soil horizons and layers weakened relationships and created non unique interpretations for em the pennsylvania site is was underlain by clayey residuum and limestone bedrock the clayey residuum is opaque to gpr and observation depths are severely restricted em induction effectively characterized the depths to bedrock within the pennsylvania site the integrated use of both methods supported by commensurate ground truth verifications helped to increase confidence in interpretations

magnetic resonance sounding and radiomagnetotelluric measurements used to characterize a limestone aquifer in gotland sweden summary almost all drinking water in gotland is groundwater and is mainly found in karst limestone however the unpredictable location and geometry of the karst cracks and caverns makes it very difficult to estimate groundwater storage and movement as well as contaminant transport the aim of this study was to test the performance of different geophysical techniques like magnetic resonance sounding mrs radiomagnetotelluric rmt vertical electrical sounding ves and ground penetrating radar gpr to characterize aquifers in gotland in respect to geometry and storage as well as connectivity over a wider area the investigated area is located on the south eastern part of gotland the geology here is dominated by 50 60 m thick successions of limestone that gradually turn into marlstone the use of multiple techniques has shown to give a more coherent interpretation however the shallow penetration depth of gpr and the lack of soil cover in some places of the investigated area limit the use of geoelectrical methods and gpr with mrs water are found down to 60 m in depth with a maximum water content at depths of 20 30 m this coincides with the most resistive sections of the limestone the water content varies between 0 and 3 with a relaxation time t1mrs less than 400 ms suggesting that the aquifer is hosted in small fractures molds and vugs rather than larger karst fractures and caverns two potential aquifers were identified with mrs possibly separated by marlstone from modeling it can be seen that such boundary separating two aquifer apart can be more easily discriminated in the n s than in the e w direction in summary mrs is therefore the only method in this survey that can detect and determine the vertical and lateral distribution of water within the aquifer together with the total volume of free water the rmt method has shown to be effective in characterizing the limestone marl interface but also to locate anomalous low resistive zones possibly associated with salt water rmt also helps to constrain the final mrs model by choosing a suitable regularization for the mrs 3d inversion all together the combination of mrs and rmt seems most efficient of the tested methods and therefore most promising for future groundwater explorations in geological environments like in eastern gotland

the role of transient disturbances in the dynamics of the pacific north american pattern abstract a 25 yr dataset is used to investigate the role of transient eddies in the dynamics of the pacific north american pna pattern monthly mean vorticity and sensible heat flux divergences associated with submonthly transients are computed over the northern hemisphere for each winter month these fields are composited over months with strong pna patterns and the average over all winter months is subtracted to obtain anomaly fields the vorticity flux divergence anomaly is found to be well correlated with the pna height field particularly in the upper troposphere where an eddy vorticity flux convergence divergence is found in the low high height regions of the pna anomaly the sensible heat flux divergence on the other hand is negatively correlated with the pna temperature anomaly so that the transient eddies produce a sensible heat flux out of the warm regions of the pna and into the cold regions thus tending to destroy the temperature anomaly a linear quasi nondivergent global steady s

detection of a subglacial lake in glacier de tete rousse mont blanc area france the processes that form intraglacial lakes are poorly understood because of the difficulty in detecting and assessing such hidden lakes extensive geophysical surveys were performed between 2007 and 2010 in order to reassess the risk of an outburst flood from glacier de tete rousse where outburst flooding from an intraglacial lake caused 175 fatalities in 1892 our geophysical survey combined ground penetrating radar measurements and nuclear magnetic resonance imaging we found a subglacial water filled reservoir with a volume of 55 000 m 3 artesian outpourings occurred when the subglacial cavity was reached by two borehole drillings indicating that the hydrostatic water pressure exceeded the ice pressure at the bottom of the cavity on the basis of these geophysical and glaciological findings we warned the public authorities in july 2010 of the risk facing the 3000 inhabitants downstream of the glacier the subglacial reservoir was drained artificially this example demonstrates how geophysical surveys can be used to detect this type of hazard when it is suspected in particular when no hydraulic outlet from the snout exists numerous ice temperature measurements have shown that the tongue of this glacier is cold based this thermal regime could explain the accumulation of water in this glacier

persistent anomalies of the extratropical northern hemisphere wintertime circulation structure abstract in a previous study of the extratropical northern hemisphere wintertime circulation significant variations were described in the occurrence of anomalies that persist beyond the durations associated with synoptic scale variability persistent anomalies the present study extends that work by identifying the typical structures of persistent anomalies focusing on whether persistent occur in certain key regions the central north pacific pac the eastern north atlantic atl and the northern soviet union nsu are related to recurrent large scale flow patterns for each region detailed comparisons are provided of the flow patterns associated with persistent positive and negative anomaly cases and with the patterns obtained in other observations and theoretical studies of persistent phenomena the results provide evidence for the recurrence of certain preferred anomaly patterns to a first approximation the composite anomaly patterns of the positive and negative cases for a region can be de

enso like interdecadal variability 1900 93 a number of recent studies have reported an enso like eof mode in the global sea surface temperature sst field whose time variability is marked by an abrupt change toward a warmer tropical eastern pacific and a colder extratropical central north pacific in 1976 77 the present study compares this pattern with the structure of the interannual variability associated with the enso cycle and documents its time history back to 1900 the analysis is primarily based on the leading eofs of the sst anomaly and anomaly deviation fields in various domains and the associated expansion coefficient or principal component time series which are used to construct global regression maps of sst sea level pressure slp and a number of related variables the use of anomaly deviations i e departures of local sst anomalies from the concurrent global mean sst anomaly reduces the influence of global mean sst trends upon the structure of the eofs and their expansion coefficient time series an important auxiliary time series used in this study is a southern oscillation index based on marine surface observations by means of several different analysis techniques the time variability of the leading eof of the global sst field is separated into two components one identified with the enso cycle related variability on the interannual timescale and the other a linearly independent residual comprising all the interdecadal variability in the record the two components exhibit rather similar spatial signatures in the global sst slp and wind stress fields the sst signature in the residual variability is less equatorially confined in the eastern pacific and it is relatively more prominent over the extratropical north pacific the corresponding slp signature is also stronger over the extratropical north pacific and its counterpart in the cold season 500 mb height field more closely resembles the pna pattern the amplitude time series of the enso like pattern in the residual variability reflects the above mentioned shift in 1976 77 as well as a number of other prominent features including a shift of opposite polarity during the 1940s

storminess and surges in the south western approaches of the eastern north atlantic the synoptic climatology of recent extreme coastal storms abstract the climatology of intense winter cyclone events in the eastern north atlantic responsible for high magnitude surge generation top 1 of events within the region of the south western approaches to northwest france and southwest england is extracted from daily sea level and 500 hpa level atmospheric pressure analyses cluster analysis yields discrete cyclone track regimes linked to upper airflow patterns being responsible for the generation of intense storms central pressure at sea level 990 hpa which promote severe surge events 60 cm along the french coast of the south western approaches fluctuations in storminess are strongly influenced by the southward intrusion and strengthening of the jet stream in mid atlantic these occurrences are often associated with negative sea surface temperature sst anomalies near newfoundland and a strengthening of the thermal gradient across the atlantic well to the south of its normal position resultant cyclogenesis promotes storms displaying a delay in minimum central pressure attainment until well east of 14 w encouraging enhancement of surge flow stepwise multiple regression analysis indicates that the most influential variables in promoting severe surge events in the south western approaches are trans atlantic sea surface temperature gradients the most important influence is the prevailing west east sea surface temperature gradient during the month of the storm followed by that for the prior month of the storm and thirdly the north south sea surface temperature gradient prevailing during the month of the event other influential variables reflect the character of the cyclone storm duration mean deepening rate of storm central pressure the value of the outermost closed isobar around the storm centre and the longitudinal position of the outermost closed isobar to the right of the cyclone track in contrast the north atlantic oscillation nao is not very effective as a discriminator of surge activity this may reflect the greater intra month volatility of parameters used to derive the nao index than of other monthly variables considered in the study the lack of resolvability at the individual storm level probably also arises because of the monthly detailing of the nao against storms of 2 3 days duration this behavioural model of extreme storminess in the south western approaches to northwest france provides the basis by which extremes of coastal susceptibility can be calibrated

mechanisms of subglacial cavity filling in glacier de tete rousse french alps the deadliest outburst flood from an englacial cavity occurred on glacier de tete rousse in the mont blanc area french alps in 1892 a subglacial reservoir was discovered in the same glacier in 2010 and drained artificially in 2010 2011 and 2012 to protect the 3000 inhabitants downstream the mechanism leading to the spontaneous refilling of the cavity following these pumping operations has been analyzed for this purpose the subglacial water volume changes between 2010 and 2013 were reconstructed the size of the cavity following the pumping was found to have decreased from 53 500 m 3 in 2010 to 12 750 m 3 in 2013 creep and the partial collapse of the cavity roof explain a large part of the volume loss analysis of cavity filling showed a strong relationship between measured surface melting and the filling rate with a time delay of 4 6 hours a permanent input of 15 m 3 d 1 not depending on surface melt was also found the meltwater and rain from the surface is conveyed to bedrock through crevasses and probably through a permeable layer of rock debris at the glacier bed the drainage pathway permeability was estimated at 0 054 m s 1 from water discharge measurements and dye tracing experiments

crosshole seismic ct data field experiments and interpretation for karst caves in deep foundations abstract foundations at karstic terrains often cause instability problems for the supporting piles of upper buildings resulting in uneven settlement and or rock failure borehole investigation of the study site showed that the limestone cavities existed from 77 0 m to 100 1 m below the surface with the mean dimension of 1 52 m and maximum of 8 0 m however it is difficult to characterize these deeply buried karst caves accurately and completely in this study we used crosshole seismic ct techniques to image the p wave velocities of the limestone stratum field experiments were designed to acquire seismic data from 44 boreholes and 113 survey lines at depths of 75 m the inverted p wave velocities were iterated by combining the shortest path raytracing method and the damped least square qr decomposition lsqr method on the basis of the initial model issues including the inverted velocities uncertainty stability and resolution of the results and ray coverage were evaluated from the synthetic model as bases for the interpretation of cavities fractures and fillings the quantitative relationship between p wave velocities and geological anomalies was consequently obtained through correlating the results of field tomography and ultrasonic tests to the borehole data and limestone samples from karst foundations respectively representative p wave velocity maps were shown and the interpreted cavities were projected onto horizontal planes two sampling boreholes and in situ water injection pumping tests verified the interpretations regarding the number and scale of cavities each area was divided into three engineering geological zones providing references for the grouting proposals of different zones

subsurface initiation of tafoni in granite terrains geophysical evidence from ne spain geomorphological implications abstract granite cavities in the north east of spain which developed below the weathering front are reported these cavities up to 3 m across and probably filled with water saturated weathered granite have been detected by electrical resistivity tomography ert as low resistivity anomalies enclosed in high resistivity media corresponding to unweathered granite rock the caverns appear as hyperbolic reflections in a radargram obtained by ground penetrating radar gpr and show similar shape and size to the tafoni found in the surrounding granite outcrops data gathered in this study support a subterranean origin of some of the tafoni a new conceptual model for the initiation and growth of granite cavities under subsurface conditions is proposed groundwater flow through vertical and sheet fractures triggers preferential weathering at points where meter sized spheroidal pockets of weathered granite develop erosion of the rock mass leads to the exposure of these pockets evolving under subaerial conditions as typical tafoni

atmospheric sensitivity to sst near the kuroshio extension during the extratropical transition of typhoon tokage abstract it is hypothesized that the tropical to extratropical transition of a cyclone in the western north pacific can be sensitive to the underlying sea surface temperature sst distribution this hypothesis was tested through a case study of typhoon tokage using a series of high resolution simulations by the weather research forecast wrf numerical weather prediction model simulations were carried out for a control sst distribution and for sst distributions with imposed warm and cold perturbations of 1 5 c maximum amplitude in the vicinity of the kuroshio extension the simulations with the warm sst perturbation yielded a cyclone slightly weaker than in the control sst case about 2 days after transition in contrast the cold sst perturbation case yielded a cyclone with a central pressure 10 hpa lower than in the control case at the same point in the storm s life cycle apparently due to its more northward track and hence closer proximity to an approaching upper level trough and perhaps in associati

using 2d inversion of magnetic resonance soundings to locate a water filled karst conduit a new methodology for magnetic resonance sounding mrs data acquisition and interpretation was developed for locating water filled karst cavities this methodology was used to investigate the ouysse karst system in the poumeyssens shaft in the causse de gramat france a new 2d numerical mrs response model was designed for improved accuracy over the previous 1d mrs approach a special survey performed by cave divers confirmed the accuracy of the mrs results field results demonstrated that in favourable conditions a low em noise environment and a relatively shallow large target the mrs method used with a coincident transmitter receiver loop can be an effective tool for locating a water filled karst conduit it was shown numerically that because an a priori orientation of the mrs profile with the karst conduit is used in the inversion scheme perpendicular for instance any error in this assumption introduces an additional error in locating the karst however the resulting error is within acceptable limits when the deviation is less than 30 the mrs results were compared with an electrical resistivity tomography ert survey it was found that in poumeyssens ert is not able to locate the water filled karst on the other hand ert provides additional information about heterogeneities in the limestone

time lapse electrical resistivity imaging of solute transport in a karst conduit the use of electrical resistivity surveys to locate karst conduits has shown mixed success however time lapse electrical resistivity imaging combined with salt injection improves conduit detection and can yield valuable insight into solute transport behaviour we present a proof of concept above a known karst conduit in the kentucky horse park lexington kentucky a salt tracer solution was injected into a karst window over a 45 min interval and repeat resistivity surveys were collected every 20 min along a 125 m transect near a monitoring well approximately 750m downgradient from the injection site in situ fluid conductivity measurements in the well peaked at approximately 25 of the initial value about 3 h after salt injection time lapse electrical resistivity inversions show two broad zones at the approximate conduit depth where resistivity decreased and then recovered in general agreement with in situ measurements combined salt injection and electrical resistivity imaging are a promising tool for locating karst conduits the method is also useful for gaining insight into conduit geometry and could be expanded to include multiple electrical resistivity transects

contribution of magnetic resonance soundings for characterizing water storage in the unsaturated zone of karst aquifers understanding the role of the unsaturated zone in aquifer recharge and contaminant attenuation processes is a major challenge for the protection and management of karstic water resources we present the potential of the magnetic resonance soundings mrs geophysical method for characterizing the vadose zone of karst aquifers composed of epikarst and infiltration layers to investigate the hydraulic functioning of the durzon karst system located on the larzac plateau southern france we used the mrs method at 16 sites the mrs results have been compared with available geologic information and to core water content measurements the remarkable spatial variability of the mrs response observed in the study area makes it possible to determine ranges of water storage properties in relation to the lithology of the investigated carbonate formations dolomite marly and siliceous limestone all soundings found either constant or increasing mrs water content with depth which demonstrates that the infiltration zone might be the major water storage entity for permanent water storage with important consequences for recharge quality and quantity these results show the feasibility and potential of the mrs method for the characterization of the karst unsaturated zone and for understanding the vertical distribution of water content which impacts the overall functioning of karst systems read more http library seg org doi 10 1190 geo2015 0411 1

seismic study of the low permeability volume in southern france karst systems locating groundwater in deep seated karst aquifers is inherently difficult with seismic methods we studied the upper epikarst and the underneath low permeability volume lpv of several karst systems located in the southern quercy and larzac regions of france and found that refraction tomography was effective only in the epikarst and not in the lpv we evaluated a 3d case study using a combination of surface records and downhole receivers to overcome this limitation this 3d approach unveiled a set of elongated furrows at the base of the epikarst and identified heterogeneities deep inside the lpv that may represent high permeability preferred pathways for water inside the karst to achieve the same result when no borehole was available we studied seismic amplitudes of the wavefield recognizing that wave induced fluid flow in low permeability carbonates is a driving mechanism of seismic attenuation we developed a workflow describing the heterogeneity of the lpv with spectral attributes derived from surface consistent decomposition principles and we validated its effectiveness at benchmark locations we applied this workflow to the 3d study and found a low amplitude signal area at depth we interpreted this anomaly as a water saturated body perched above the aquifer

spatial patterns of atmosphere ocean interaction in the northern winter abstract the variability of monthly mean sea surface temperature sst anomalies over the extratropical north atlantic and pacific and its relation to atmospheric circulation anomalies over the northern hemisphere during wintertime is investigated by applying eigenvector analysis to a 39 year dataset and correlating the time series of the resulting expansion coefficients with the hemispheric 500 mb height and sea level pressure fields in agreement with previous studies the simultaneous correlation between the tone series of the expansion coefficient of the first empirical orthogonal function eof 1 of north pacific sea surface temperature sst and the hemispheric 500 mb height field resembles the pacific north american pattern and the corresponding pattern for atlantic sst resembles the north atlantic oscillation in the vicinity of the conters of action of thew patterns the sst fluctuations associated with these modes explain on the order of half the variance of 500 mb height and slightly less of