a simple multicloud parameterization for convectively coupled tropical waves part i linear analysis abstract recent observational analysis reveals the central role of three multicloud types congestus stratiform and deep convective cumulus clouds in the dynamics of large scale convectively coupled kelvin waves westward propagating two day waves and the madden julian oscillation a systematic model convective parameterization highlighting the dynamic role of the three cloud types is developed here through two baroclinic modes of vertical structure a deep convective heating mode and a second mode with low level heating and cooling corresponding respectively to congestus and stratiform clouds a systematic moisture equation is developed where the lower troposphere moisture increases through detrainment of shallow cumulus clouds evaporation of stratiform rain and moisture convergence and decreases through deep convective precipitation a nonlinear switch is developed that favors either deep or congestus convection depending on the relative dryness of the troposphere in particular a dry troposphere

multi level slug tests in highly permeable formations 1 modification of the springer gelhar sg model a multi level slug test model and a method for the evaluation of vertical profiles of hydraulic conductivity in highly permeable formations are developed a double packer system is employed to estimate local hydraulic conductivity depending on the formation and double packer system parameters the water level recovery in the tested well can exhibit a monotonic or oscillatory response to discern information on aquifer properties from artifacts introduced by the measurement system the theory of flow in an aquifer and a double packer system is developed the mathematical model incorporates features of the springer and gelhar 1991 model and reduces to the bouwer and rice 1976 model in a special case the model involves equations of momentum and mass conservation for the double packer system with quasi steady well aquifer interaction equations the method is uniformly applicable for both monotonic and oscillatory well responses and can produce profiles of hydraulic conductivity for the tested well the criterion is given to determine the type of well response for given slug test conditions

messinian evaporite deposition during sea level rise in the gulf of lions western mediterranean the messinian salinity crisis resulted from desiccation of the mediterranean sea after its isolation from the atlantic ocean at the end of the miocene stratal geometry tied to borehole data in the gulf of lions show that the pre crisis continental shelf has been eroded during a major sea level fall and that sediments from this erosion have been deposited in the basin this detrital package is onlapped by high amplitude seismic reflectors overlain by the messinian salt and the upper evaporites towards the shelf the transition between regressive deposits and overlying onlapping sediments is characterised by a wave ravinement surface suggesting that a significant part of the onlapping reflectors and overlying messinian evaporites were deposited during a relatively slow landward migration of the shoreline the clear boundary between the smooth wave ravinement surface and the subaerial messinian erosional surface observed on the gulf of lions shelf and onshore in the rhone valley is interpreted to have resulted from a rapid acceleration of the mediterranean sea level rise at the end of the messinian salinity crisis numerical simulation of this cycle of sea level change during the messinian salinity crisis and of precipitation of thick evaporites during the slow sea level rise shows that this scenario can be modelled assuming a value of evaporation minus precipitation of 1 75 m3 m2 yr in the deep mediterranean basins

messinian erosional and salinity crises view from the provence basin gulf of lions western mediterranean abstract though the late miocene messinian salinity crisis has been intensely researched along the circum mediterranean basins few studies have focused on the central part of the mediterranean basin and especially the pre salt deposits to improve our knowledge of the messinian events it is imperative to better understand this domain in this study we provide a more complete understanding of this central domain in the provence basin we were able to recognize a thick marine detrital series up to 1000 m derived from the messinian subaerial erosion which is partly prolongated in the distal part by b a thick unit of deep marine deposits up to 800 m prior to the evaporites c a thick presumed alternation of detritals and evaporites 1500 m below the mobile halite and d a two step transgression at the end of the messinian spatially we document the eroded shelf to the deep basin and from the western to the eastern parts of the gulf of lions and temporally we extend the interpretations from the early deposition of detritic sediments to the final sea level rise the results provide a new basis for discussion not only for the development of the messinian salinity crisis but also for the reconstruction of the subsidence history of the provence basin

multi scale aquifer characterization and groundwater flow model parameterization using direct push technologies direct push dp technologies are typically used for cost effective geotechnical characterization of unconsolidated soils and sediments in more recent developments dp technologies have been used for efficient hydraulic conductivity k characterization along vertical profiles with sampling resolutions of up to a few centimetres until date however only a limited number of studies document high resolution in situ dp data for three dimensional conceptual hydrogeological model development and groundwater flow model parameterization this study demonstrates how dp technologies improve building of a conceptual hydrogeological model we further evaluate the degree to which the dp derived hydrogeological parameter k measured across different spatial scales improves performance of a regional groundwater flow model the study area covers an area of 60 km2 with two overlying mainly unconsolidated sand aquifers separated by a 5 7 m thick highly heterogeneous clay layer in north eastern belgium the hydrostratigraphy was obtained from an analysis of cored boreholes and about 265 cone penetration tests cpts the hydrogeological parameter k was derived from a combined analysis of core and cpt data and also from hydraulic direct push tests a total of 50 three dimensional realizations of k were generated using a non stationary multivariate geostatistical approach to preserve the measured k values in the stochastic realizations the groundwater model k realizations were conditioned on the borehole and direct push data optimization was performed to select the best performing model parameterization out of the 50 realizations this model outperformed a previously developed reference model with homogeneous k fields for all hydrogeological layers comparison of particle tracking simulations based either on the optimal heterogeneous or reference homogeneous groundwater model flow fields demonstrate the impact dp derived subsurface heterogeneity in k can have on groundwater flow and solute transport we demonstrated that dp technologies especially when calibrated with site specific data provide high resolution 3d subsurface data for building more reliable conceptual models and increasing groundwater flow model performance

spatial characterization of the hydraulic conductivity using direct push injection logging 1 detailed information on the spatial structure of hydraulic conductivity k is important for understanding and predicting groundwater flow and transport direct push injection logging dpil is a promising technology for rapid measurement of k in unconsolidated formations this technology was used to gain information on the highly heterogeneous aquifer at the lauswiesen test site in germany using a large body of dpil and direct push slug testing measurements we characterize the structure of k on scales not previously possible two new applications of dpil are put forward 1 use of raw dpil measurements of relative conductivity kr to characterize the spatial distribution of k and 2 transformation of kr measurements to k values based on their statistical moments the dpil results are compatible to those obtained using more conventional methodologies the main achievement of the methodology is the possibility to delineate deterministic aquifer subunits as well as the identification of the statistical parameters of the log conductivity for each subunit in particular the horizontal integral scale i a parameter affecting solute transport is difficult and costly to identify using other approaches nevertheless further studies are needed to clarify questions on low kr measurements and the nature of the relationship between kr and k

zonal and vertical structure of the madden julian oscillation abstract a statistical study of the three dimensional structure of the madden julian oscillation mjo is carried out by projecting dynamical fields from reanalysis and radiosonde data onto space time filtered outgoing longwave radiation olr data mjo convection is generally preceded by low level convergence and upward motion in the lower troposphere while subsidence cooling and drying prevail aloft this leads to moistening of the boundary layer and the development of shallow convection followed by a gradual and then more rapid lofting of moisture into the middle troposphere at the onset of deep convection after the passage of the heaviest rainfall a westerly wind burst region is accompanied by stratiform precipitation where lower tropospheric subsidence and drying coincide with continuing upper tropospheric upward motion the evolution of the heating field leads to a temperature structure that favors the growth of the mjo the analysis also reveals distinct differences in the vertical structure

a possible new mechanism for northward propagation of boreal summer intraseasonal oscillations based on trmm and merra reanalysis boreal summer intraseasonal oscillations bsisos manifest in the active and break spells and act as the primary building block of the indian summer monsoon although recent research has evolved a basic framework for understanding the scale selection and northward propagation of the bsiso the role of different hydrometeors in modulating these processes remains poorly explored in this study trmm 2a12 retrievals and modern era retrospective analysis for research and applications reanalysis data are examined to establish relationship between cloud hydrometeors and other atmospheric dynamical parameters with the northward propagation of the bsisos the study reveals that the cloud liquid water leads the deep convection during the northward propagation of bsisos in the lower troposphere while the cloud ice slightly lags the convection this distribution indicates the occurrence of a possible mechanism of the lower level moistening through the large scale moisture advection in lower atmosphere and boundary layer pbl convergence followed by triggering of the deep convection the analyses of moisture advection and the dynamical fields with respect to the convection center show that low level moistening is a manifestation of the barotropic vorticity and pbl convergence of moisture anomaly north of the convection center a new internal dynamical thermodynamical mechanism is unraveled to understand the reason behind the middle tropospheric heating maximum and its role on the northward propagation it is shown that the enhanced moisture perturbation in lower levels together with the heat transport by the sub grid scale eddies within the pbl induces lower level instability required to precondition the lower atmosphere for triggering the deep convection vigorous upward motion inside the deep convection uplifts the liquid hydrometeors to upper levels and the formation of precipitable ice leads to the heating maxima in the middle troposphere to check the robustness of the proposed hypothesis similar analysis is performed for the weak northward propagating bsiso cases

stochastic parameterization of convective area fractions with a multicloud model inferred from observational data abstractobservational data of rainfall from a rain radar in darwin australia are combined with data defining the large scale dynamic and thermodynamic state of the atmosphere around darwin to develop a multicloud model based on a stochastic method using conditional markov chains the authors assign the radar data to clear sky moderate congestus strong congestus deep convective or stratiform clouds and estimate transition probabilities used by markov chains that switch between the cloud types and yield cloud type area fractions cross correlation analysis shows that the mean vertical velocity is an important indicator of deep convection further it is shown that if conditioned on the mean vertical velocity the markov chains produce fractions comparable to the observations the stochastic nature of the approach turns out to be essential for the correct production of area fractions the stochastic multicloud model can easily be coupled to existing moist convection parameterization schemes used in ge

three dimensional model of modern channel bend deposits 1 we present a three dimensional model of heterogeneous modern channel bend deposits developed through purely structure imitating interpolation kriging of hydraulic properties this model augmented with ground penetrating radar data and directional variograms agrees with detailed observations in similar modern environments and leads to a process based interpretation of the presented hydraulic conductivity structure integration of all available information permitted delineation and characterization of the modern streambed as a distinct hydrostratigraphic unit without coring or outcrop studies our results imply that the modern streambed is commonly oversimplified in available analytical and numerical models of groundwater surface water interactions where it is assumed to be homogeneous and isotropic and characterized by a constant width and thickness this three dimensional approach that integrates concepts and principles developed in sedimentology hydrogeology geophysics and geostatistics has potential implications on model development of stream aquifer systems

sea level and climatic controls on turbidite occurrence for the past 26 kyr on the flank of the gaoping canyon off sw taiwan submarine canyons are major conduits for delivery of sediments originating from the continental margin into the deep sea here we analyze the effects of changing sea levels and climate e g sediment supply on the frequency of turbidites over the last 26 kyr our study is based on high resolution age controls for turbidites in core md178 10 3291 from a water depth of 2070 m on the flank of the gaoping canyon offshore in sw taiwan unlike most other submarine canyons worldwide the head of the gaoping canyon has remained connected to the river mouth during the recent flooding of the continental shelf our results reveal that turbidity currents are less frequent during periods of sea level lowstand in contrast turbidity currents have been more frequent since 12 kyr bp during the final stage of rising sea level and sea level highstands this may be the result of increased terrestrial sediment delivery due to enhanced rainfall intensity moreover comparing to other source to sink systems the turbidite occurrence in the flank of gaoping canyon through the last glacial cycle might have been more strongly influenced by climatic changes due to short sediment storage response time

twin lake tracer tests setting methodology and hydraulic conductivity distribution following evaluation of three potential sites a fluvial sand aquifer with high 0 7 1 6 m d 1 linear average groundwater flow velocities was instrumented with a fully penetrating injection well and 82 monitoring installations over a 40 m flow path length two natural gradient tracer migration experiments have employed pulse injections of a nonreactive radioisotope 131i in a study of hydraulic conductivity structure and dispersive characteristics of the flow system the use of a gamma emitting radionuclide in these experiments allowed measurement of tracer distribution by scanning fully penetrating boreholes with a scintillation detector this technique provided many advantages in data collection over conventional tracers including unprecedented resolution of the vertical distribution of tracer measurements without pumping and the attendant concerns for flow system perturbation and minimal manpower for sample analysis tracer breakthroughs at monitors along the axis of flow revealed the presence of heterogeneities in aquifer hydraulic conductivity at two scales over the 40 m path length six regions with hydraulic conductivities substantially different from adjacent strata were identified thicknesses of these regions varied from 0 2 to more than 3 m their lateral extents in the direction of groundwater flow ranged from 15 m to more than 40 m smaller strata with an average thickness of 0 34 m and lengths of less than 10 m were detected within all six of the hydraulic conductivity regions but there was no evidence of increases in local dispersivity with increased transport distance as a result of these variations the six hydraulic conductivity regions do however have measurable effects on whole aquifer dispersion stratification characteristics of the tested aquifer believed to have been deposited in a sandy braided river are consistent with those observed in similar modern environments estimation of the magnitude and spatial structure of hydraulic conductivity variations in aquifers of concern would be greatly aided by studies of the stratification characteristics in well exposed modern or lithified sedimentary analogues

monsoon convection in the himalayan region as seen by the trmm precipitation radar three dimensional structure of summer monsoon convection in the himalayan region and its overall variability are examined by analyzing data from the tropical rainfall measuring mission trmm precipitation radar over the june september seasons of 2002 and 2003 statistics are compiled for both convective and stratiform components of the observed radar echoes deep intense convective echoes 40 dbz echo reaching heights 10 km occur primarily just upstream south of and over the lower elevations of the himalayan barrier especially in the northwestern concave indentation of the barrier the deep intense convective echoes are vertically erect consistent with the relatively weak environmental shear they sometimes extend above 17 km indicating that exceptionally strong updraughts loft graupel to high altitudes occasionally scattered isolated deep intense convective echoes occur over the tibetan plateau wide intense convective echoes 40 dbz echo 1000 km2 in horizontal dimension also occur preferentially just upstream of and over the lower elevations of the himalayas most frequently in the northwestern indentation of the barrier the wide intense echoes have an additional tendency to occur along the central portion of the himalayas and they seldom if ever occur over the tibetan plateau the wide intense echoes exhibit three mesoscale structures amorphous areas lines parallel to the mountain barrier and arc shaped squall lines perpendicular to and propagating parallel to the steep himalayan barrier the latter are rare generally weaker than those seen in other parts of the world and occur when a midlevel jet is aligned with the himalayan escarpment deep and wide intense convective echoes over the northwestern subcontinent tend to occur where the low level moist layer of monsoon air from the arabian sea meets dry downslope flow in a manner reminiscent of severe convection leeward of the rocky mountains in the central usa as the low level layer of moist air from the sea moves over the hot arid northwestern subcontinent it is capped by an elevated layer of dry air advected off the afghan or tibetan plateau the capped low level monsoonal airflow accumulates instability via surface heating until this instability is released by orographically induced lifting immediately adjacent to or directly over the foothills of the himalayas broad 50 000 km2 in area stratiform echoes occur in the eastern and central portions of the himalayan region in connection with bay of bengal depressions their centroids are most frequent just upstream of the himalayas in the region of the concave indentation of the barrier at the eastern end of the range the steep topography apparently enhances the formation and longevity of the broad stratiform echoes monsoonal depressions provide a moist maritime environment for the convection evidently allowing mesoscale systems to develop larger stratiform echoes than in the western himalayan region copyright 2007 royal meteorological society

a walk down the cap de creus canyon northwestern mediterranean sea recent processes inferred from morphology and sediment bedforms the cap de creus canyon northwestern mediterranean sea belongs to a complex network of submarine canyons cutting the western gulf of lion continental shelf and opening into the larger sete canyon swath bathymetry data mak 1m deep towed side scan sonar imagery and 5 khz high resolution seismic reflection profiles show striking morphologies in the cap de creus canyon floor and walls as a consequence of the canyon head and the upper reach severe incision the continental shelf dramatically narrows in front of the creus cape promontory the upper canyon has a flat bottomed thalweg incised in a mega scale sediment furrow field displaying hyperbolic seismic facies the tens of kilometres long linear furrows extend also over the middle canyon down to 1400 m of water depth the furrows on either side of the canyon are not parallel but oblique and display varying degrees of excavation mid channel sediment bars are locally present in the thalweg which is made of sandy lag deposits as revealed by its acoustic response and verified by sediment samples the middle canyon is linear and steep with an up to 700 m high southern wall contrasting with the sinuous smooth lower canyon which is controlled by flowage of the underlying messinian evaporites large sections of the canyon are affected by sediment instability processes the lower cap de creus canyon hangs up to 260 m over its distalmost reach and the sete canyon through a narrow less than 1 km wide gorge numerous scours up to 10 m deep suggesting bed load transport occupy the lower sete canyon immediately downstream of the cap de creus canyon mouth the data set provides the first complete very high resolution imaging of a submarine canyon from its upper part down to its distalmost reach the observations evidence a wide set of erosion transport and deposition processes along the cap de creus canyon including sediment entrapment at the canyon head furrow generating dense water cascading through the southern wall along channel currents strong enough to excavate specific sections of the channel floor and bed load sediment transport as demonstrated by the presence of mega ripples crescent scours and grooves in the lower canyon

a new method for the determination of in situ hydraulic properties by pressure pulse tests and application to the higashi hachimantai geothermal field a new method is proposed to evaluate in situ hydraulic properties of formations using the so called pressure pulse test over short test intervals the analysis utilizes the continuous distribution of instantaneous ring sources of fluid over the well bore surface in order to reduce the problem to a set of singular integral equations for a homogeneous and isotropic porous medium when the ratio of the test interval length to well bore diameter is small or the specific storage is small the flow parallel to the well bore axis becomes significant and the shape of the type curves obtained from the present analysis is different from that of the conventional type curves use of the conventional type curves should be restricted to intervals that are more than 20 times longer than the well bore diameter finally the present method is applied to evaluate the in situ hydraulic properties of the higashi hachimantai geothermal model field of hot dry rock tohoku university

a model for convectively coupled tropical waves nonlinearity rotation and comparison with observations abstract recent observational analysis of both individual realizations and statistical ensembles identifies moist convectively coupled kelvin waves in the tropics with supercluster envelopes of convection this observational analysis elucidates several key features of these waves including their propagation speed of roughly 15 m s 1 and many aspects of their dynamical structure this structure includes anomalously cold temperatures in the lower troposphere and warm temperatures in the upper troposphere below 250 hpa within and sometimes leading the heating region and strong updrafts in the wave and an upward and westward tilting structure with height below roughly 250 hpa other key features in the wave are that anomalous increases in convective available potential energy cape and surface precipitation lead the wave while the trailing part of the supercluster is dominated by stratiform precipitation the main result in this paper is the development of a simple model convective parameterization with n

the structural evolution of the messinian evaporites in the levantine basin abstract the levantine basin in the south eastern mediterranean sea is a world class site for studying the initial stages of salt tectonics driven by differential sediment load because the messinian evaporites are comparatively young the sediment load varies along the basin margin they are hardly tectonically overprinted and the geometry of the basin and the overburden is well defined in this study we analyse depositional phases of the evaporites and their structural evolution by means of high resolution multi channel seismic data the basinal evaporites have a maximum thickness of about 2 km precipitated during the messinian salinity crisis 5 3 5 9 ma ago the evaporite body is characterized by 5 transparent layers sequenced by four internal reflections we suggest that each of the internal reflection bands indicate a change of evaporite facies possibly interbedded clastic sediments which were deposited during temporal sea level rises all of these internal reflections are differently folded and distorted proving that the deformation was syn depositional thrust angles up to 14 are observed backstripping of the pliocene quaternary reveals that salt tectonic is mainly driven by the sediment load of the nile cone the direction of lateral salt displacement is mainly ssw nne and parallel to the bathymetric trend apparent rollback anticlines off israel result rather from differential subsidence than from lateral salt displacement in the south eastern basin margin the deposition of the isreali slump complex isc is coeval with the onset of salt tectonic faulting suggesting a causal link between slumping processes and salt tectonics the superposition of thin skinned tectonics and thick skinned tectonics becomes apparent in several locations the fold belt off the israeli mediterranean slope mainly results from active strike slip tectonics which becomes evident in faults which reach from the seafloor well below the base of the evaporites owing to the wrenching of the crustal segments which are bounded by deep rooted fault lines like the damietta latakia pelusium and shelf edge hinge line the setting is transpressional south of 32 n where the fault lines bend further towards the west this adds a component of thick skinned transpression to the generally thin skinned compressional regime in the basin above 1 5 km of evaporites a mud volcano is observed with the mud source seemingly within the evaporite layer at the eastern cyprus arc the convergence zone of the african and the anatolian plates deep rooted compression heavily deformed the base of the evaporites whereas at the eratosthenes seamount mainly superficial compression affecting the post messinian sediments and the top of the evaporites is observed

correlation between onshore and offshore pliocene quaternary systems tracts below the roussillon basin eastern pyrenees france abstract the western part of the gulf of lions was chosen for conducting the first correlative studies between the terrestrial pliocene quaternary sedimentary formations roussillon basin and their extension on the adjacent continental shelf the work was based on a study of 32 wells drilled onshore and elf aquitaine seismic lines offshore the correlations are based on equivalence between the two domains in terms of stacking patterns biostratigraphy and geometry the post messinian sedimentation within the study area is characterised by eight equivalent order stacking patterns represented by eight dominantly prograding systems tracts furthermore comparison of the spatial positions of offlap breaks on several seismic profiles provides a better understanding of the roles of tectonism eustasy and sedimentary supply in the stacking of the identified sequences

realistic initiation and dynamics of the madden julian oscillation in a coarse resolution aquaplanet gcm 1 the main mechanisms for the initiation and propagation of the madden julian oscillation mjo are still widely debated the capacity of operational global climate models gcms to correctly simulate the mjo is hindered by the inadequacy of the underlying cumulus parameterizations here we show that a coarse resolution gcm coupled to a simple multicloud model parameterization mimicking the observed dynamics and physical structure of organized tropical convection simulates the mjo in an idealized setting of an aquaplanet without ocean dynamics we impose a fixed nonhomogeneous sea surface temperature replicating the indian ocean western pacific warm pool this results in a succession of mjos with realistic phase speed amplitude and physical structure each mjo event is initiated at a somewhat random location over the warm pool and dies sometimes near the eastern boundary of the warm pool and sometimes at a random location way beyond the warm pool also occasionally the mjo events stall at the center of maximum heating this is reminiscent of the fact that in nature some mjos stall over the maritime continent while others reach the central pacific ocean and beyond the initiation mechanism in the model is believed to be a combination of persistent intermittent convective events interacting with observed large scale flow patterns and internal tropical dynamics the large scale flow patterns are associated with planetary scale dry kelvin waves that are triggered by preceding mjo events and circle the globe while congestus cloud decks on the flanks of the warm pool are believed to force rossby gyres which then funnel moisture toward the equatorial region

new multiscale models and self similarity in tropical convection abstract one of the unexplained striking features of tropical convection is the observed statistical self similarity in clusters superclusters and intraseasonal oscillations through complex multiscale processes ranging from the mesoscales to the equatorial synoptic scales to the intraseasonal planetary scales here new multispatial scale multitime scale simplified asymptotic models are derived systematically from the equatorial primitive equations on the range of scales from mesoscale to equatorial synoptic to planetary intraseasonal which provide a useful analytic framework for addressing these issues new mesoscale equatorial synoptic dynamical mesd models and balanced mesd bmesd models are developed for the multitime multispace interaction from mesoscales to equatorial synoptic scales new multitime versions of the intraseasonal planetary equatorial synoptic dynamics ipesd models are developed for multiple spatiotemporal interactions on equatorial synoptic scales and planetary scales the m

a method to estimate hydraulic conductivity from bulk geochemical compositions a new method has been developed to estimate the hydraulic conductivity in unconsolidated aquifers the method uses bulk geochemical compositions correlated with hydraulic conductivities measured by pumping tests the concept is based on a general rule that hydraulic conductivity is principally controlled by grain size distribution and particle shape both of which relate to mineralogical composition using a minlith algorithm normative mineralogical compositions can be derived from bulk geochemical compositions economically and expediently and then correlated to the hydraulic conductivity determined by pumping tests in the field in this study 202 sediment samples from nine unconsolidated aquifers were analyzed by x ray fluorescence although hydraulic conductivity does not show a definite relationship with geochemical compositions it does demonstrate a linear logarithmic equation to the content of normative earthy minerals however linear regressed equations should not be applied to aquifers composed of medium to coarse sand and gravel sizes due to interference from lithic fragments in addition this equation tends to overestimate hydraulic conductivity possibly because the effect of compaction is ignored in this study

a method to estimate hydraulic conductivity while drilling abstract a field test and analysis method has been developed to estimate the vertical distribution of hydraulic conductivity in shallow unconsolidated aquifers the field method uses fluid injection ports and pressure transducers in a hollow auger that measure the hydraulic head outside the auger at several distances from the injection point a constant injection rate is maintained for a duration time sufficient for the system to become steady state exploiting the analogy between electrical resistivity in geophysics and hydraulic flow two methods are used to estimate conductivity with depth a half space model based on spherical flow from a point injection at each measurement site and a one dimensional inversion of an entire dataset the injection methodology conducted in three separate drilling operations was investigated for repeatability reproducibility linearity and for different injection sources repeatability tests conducted at 10 levels demonstrated standard deviations of generally less than 10 reproducibility tests conducted in three closely spaced drilling operations generally showed a standard deviation of less than 20 which is probably due to lateral variations in hydraulic conductivity linearity tests made to determine dependency on flow rates showed no indication of a flow rate bias in order to obtain estimates of the hydraulic conductivity by an independent means a series of measurements were made by injecting water through screens installed at two separate depths in a monitoring pipe near the measurement site these estimates differed from the corresponding estimates obtained by injection in the hollow auger by a factor of less than 3 5 which can be attributed to variations in geology and the inaccurate estimates of the distance between the measurement and the injection sites at depth

spatial variability of hydraulic conductivity of an unconfined sandy aquifer determined by a mini slug test abstract the spatial variability of the hydraulic conductivity in a sandy aquifer has been determined by a mini slug test method the hydraulic conductivity k of the aquifer has a geometric mean of 5 05 10 4 m s 1 and an overall variance of 1n k equal to 0 37 which corresponds quite well to the results obtained by two large scale tracer experiments performed in the aquifer a geological model of the aquifer based on 31 sediment cores proposed three hydrogeological layers in the aquifer concurrent with the vertical variations observed with respect to hydraulic conductivity the horizontal correlation length of the hydraulic conductivity has been determined for each of the three hydrogeological layers and is found to be small 1 2 5 m the asymptotic longitudinal dispersivity of the aquifer has been estimated from the variance in hydraulic conductivity and the horizontal correlation length to be in the range of 0 3 0 5 m compared with a value of 0 42 m obtained in one of the tracer tests performed

multi level slug tests in highly permeable formations 2 hydraulic conductivity identification method verification and field applications abstract using the developed theory and modified springer gelhar sg model an identification method is proposed for estimating hydraulic conductivity from multi level slug tests the computerized algorithm calculates hydraulic conductivity from both monotonic and oscillatory well responses obtained using a double packer system field verification of the method was performed at a specially designed fully penetrating well of 0 1 m diameter with a 10 m screen in a sand and gravel alluvial aquifer msea site shelton nebraska during well installation disturbed core samples were collected every 0 6 m using a split spoon sampler vertical profiles of hydraulic conductivity were produced on the basis of grain size analysis of the disturbed core samples these results closely correlate with the vertical profile of horizontal hydraulic conductivity obtained by interpreting multi level slug test responses using the modified sg model the identification method was applied to interpret the response from 474 slug tests in 156 locations at the msea site more than 60 of responses were oscillatory the method produced a good match to experimental data for both oscillatory and monotonic responses using an automated curve matching procedure the proposed method allowed us to drastically increase the efficiency of each well used for aquifer characterization and to process massive arrays of field data recommendations generalizing this experience to massive application of the proposed method are developed

using the stochastic multicloud model to improve tropical convective parameterization a paradigm example abstractdespite recent advances in supercomputing current general circulation models gcms poorly represent the variability associated with organized tropical convection a stochastic multicloud convective parameterization based on three cloud types congestus deep and stratiform introduced recently by khouider biello and majda in the context of a single column model is used here to study flows above the equator without rotation effects the stochastic model dramatically improves the variability of tropical convection compared to the conventional moderate and coarse resolution paradigm gcm parameterizations this increase in variability comes from intermittent coherent structures such as synoptic and mesoscale convective systems analogs of squall lines and convectively coupled waves seen in nature whose representation is improved by the stochastic parameterization furthermore simulations with a sea surface temperature sst gradient yield realistic mean walker cell circulation with plausible

record of the messinian salinity crisis in the sw mallorca area balearic promontory spain the current interpretation of the messinian salinity crisis msc involves the deposition of the so called peripheral or marginal evaporites in onshore basins as well as the erosion of the margins and the formation of thick evaporites in the deep parts of the basins the present study focuses on intermediate depth basins i e located between the onshore outcrops and the deep basins indeed the balearic promontory shows small stepped basins filled with msc deposits between its western extremity on the alicante shelf and its eastern end around the menorca block new and already available seismic reflection profiles and onshore data allow us to investigate the nature and geometrical relationships of these deposits in the area between the islands of ibiza and mallorca our observations suggest the existence of three msc related units in this area the lowermost transparent seismic unit can be interpreted as a 100 to 200 m thick salt layer deposited in the deepest part of the central mallorca depression these evaporites pass laterally and upward into a thin bedded seismic unit which could be lithologically equivalent to the upper evaporites of the deep basins all around the borders of the central mallorca depression this bedded seismic unit onlaps a slope unit which shows bedded to chaotic and rafted facies the messinian continental shelf is eroded and incised by a valley extending from the palma onshore area to the mallorca downslope domain our results suggest the presence offshore of at least two generations of diachronous msc deposits the observation of salt on a continental high and the widespread msc deposits on the margins of the central mallorca depression call into question the location of halite preferentially in the deep abyssal basins and the significance of the deep basin msc units that onlap onto the margin erosional surface mes as observed all around the passive margins of the northwest mediterranean basin the dual terminology used for peripheral deep msc evaporites cannot be applied to any of the msc units found in the study area

how normal faulting and sedimentation interact to produce listric fault profiles and stratigraphic wedges abstract in a series of scale experiments we generated listric normal faults by extending models composed of colored sand layers deposited at regular time intervals throughout deformation during syntectonic sedimentation progressive bulk extension along a single set of faults caused domino type tilting of fault blocks underlying tilted faults propagated upwards with constant dips into newly sedimented layers hence fault profiles become progressively more listric tilting of the free surface resulted in asymmetrical depressions and in fan shaped deposits stepwise or continuous geometric models of domino tilting and synchronous sedimentation yield the same structural and stratigraphic features as observed in the sand models the continuous geometric model shows that a critical parameter governing fault curvature is the ratio r between rates of bulk strain and sedimentation both types of models reveal that synchronous sedimentation and bulk extension are capable by themselves of generating listric normal faults

radial gravitational gliding on passive margins abstract gravitational gliding of uppermost sediments down a passive margin is possible if there is a basal layer of evaporite or other soft material to allow detachment in examples from the gulf of mexico and the brazilian margin gliding has produced three main structural domains an uppermost domain of downdip extension an intermediate domain of rigid gliding and a lowermost domain of downdip contraction domain boundaries are established by changes in slope in this paper we examine three kinds of gravitational gliding depending on the paths followed by material particles in ideal parallel gliding particle paths are parallel straight lines trending downslope this should occur where the margin is perfectly straight in ideal radial gliding particle paths are radii of a circle and the margin is shaped like a circular cone natural margins will not have ideal shapes but divergent gliding will tend to occur off coastal salients convergent gliding off coastal re entrants a simple kinematic model based on ductile behaviour illustrates some essential features of radial gliding changes in radius during divergent gliding produce strike parallel extension during convergent gliding they produce strike parallel contraction vertical strains also differ divergent gliding produces an uppermost domain of strong vertical thinning balanced by extensions in all horizontal directions similarly convergent gliding produces a lowermost domain of strong vertical thickening balanced by contractions in all horizontal directions these deformed states cannot be restored by simple techniques based on section balancing we have done three experiments using analogue materials sand to model the brittle behaviour of sediments silicone putty to model the ductile behaviour of basal layers of evaporite the experiments were properly scaled to account for gravitational forces experiment i reproduced convergent gliding above a basement with a conical upper surface strike parallel contraction was responsible for radial folds on the lower slopes the lowermost domain had a complex fold pattern indicating contraction in all horizontal directions experiment 2 reproduced divergent gliding above a basement with a pyramidal upper surface strike parallel extension produced radial rifts on the upper slopes the uppermost domain had a complex polygonal pattern of normal faults indicating extension in all horizontal directions experiment 3 also reproduced divergent gliding but due to non uniform sediment thickness we have examined the many seismic profiles both downdip and alongstrike available for the brazilian margin alongstrike profiles show structures which we attribute to strike parallel strains around the santos re entrant syn sedimentary growthfolds indicate strike parallel contraction increasing downslope this argues for a mechanism of convergent gliding in contrast around the campos salient normal growth faults and associated salt rollers indicate strike parallel extension decreasing downslope this argues for a mechanism of divergent gliding the pattern of oil fields in the campos area including the giant marlim field seems to be closely controlled by divergent gravitational gliding and associated processes radial gliding should occur on other passive margins as well especially where the coastline is sinuous structures around the western gulf of of mexico seem to indicate convergent gliding at the scale of the entire gulf structures at a smaller scale around the mississippi delta seem to indicate divergent gliding

the late messinian salinity crisis and late miocene tectonism interaction and consequences on the physiography and post rift evolution of the gulf of lions margin the interpretation of rhone maritime seismic profiles and the accurate mapping of all the structural features affecting the miocene cover made it possible for us to develop herein a new structural model for the top of the eroded miocene of the gulf of lions platform late miocene extensional faults exerted a considerable structural control on the messinian erosion in particular mapping of transfer zones has shown that these structures controlled retrogressive erosion of the platform this late miocene extension could have been caused by gravity driven destabilization of the platform associated with base level lowering at the onset of the messinian salinity crisis

detailed morphology sedimentary structure and evolution of the continental margin of the western provencal basin south of france since the late miocene abstract seabeam bathymetry and high resolution seismic profiles allow the study of different sedimentary units existing off western provence and to establish their continuity throughout the continental margin from the shelf to the rise the morphology of the slope is greatly controlled by gravity processes leading to phenomena such as canyon piracy or channel avulsion this morphology quite accurately expresses the configuration of the old underlying sedimentary and tectonic structures the sedimentary structure of this domain is the result of the complex arrangement of lobes and ridges that originated from different continental sources and were deposited during different epochs of the plio quaternary knowledge of the old hydrographic networks draining provence during the different quaternary climatic stages allows palaeogeographic reconstructions to be proposed linking these sedimentary units to their continental sources

the west african monsoon dynamics part i documentation of intraseasonal variability intraseasonal variability in the west african monsoon is documented by using daily gridded datasets of rainfall and convection and reanalyzed atmospheric fields over the period 1968 90 rainfall and convection over west africa are significantly modulated at two intraseasonal timescales 10 25 and 25 60 day leading to variations of more than 30 of the seasonal signal a composite analysis based on the dates of the maximum minimum of a regional rainfall index in wet dry sequences shows that these sequences last on average 9 days and belong to a main quasiperiodic signal of about 15 days a secondary periodicity of 38 days is present but leads to a weaker modulation during a wet dry sequence convection in the itcz is enhanced weakened and its northern boundary moves to the north south while the speed of the african easterly jet decreases increases the speed of the tropical easterly jet increases decreases and the monsoon flow becomes stronger weaker all these features being similar to the ones associated with interannual variability characterizing wet and dry years this modulation of convection at intraseasonal timescales is not limited to west africa but corresponds to a westward propagating signal from eastern africa to the western tropical atlantic an enhanced monsoon phase is associated with stronger cyclonic activity in the low levels over the sahel associated with stronger moisture advection over west africa five days before the full development of the wet phase a stronger cyclonic circulation at 20 e induces enhanced southerly winds along 25 e where convection enhances while another westwardpropagating cyclonic circulation is located at 0 this atmospheric pattern is linked to the enhancement of the subsiding branch of the northern hadley cell at 35 n northerly advection of drier air over west africa and to increased dry convection in the heat low at 20 n it propagates westward leading to a zonally extended area of enhanced monsoon winds over west africa consistent with the occurrence of the wet phase

evaluation of the homme dynamical core in the aquaplanet configuration of ncar cam4 rainfall abstractthe ncar community climate system model version 4 ccsm4 includes a new dynamical core option based on ncar s high order method modeling environment homme homme is a petascale capable high order element based conservative dynamical core developed on the cubed sphere grid initial simulations have been completed in an aquaplanet configuration of the community atmosphere model version 4 cam4 the atmospheric component of ccsm4 the authors examined the results of this simulation and assessed its fidelity in simulating rainfall which is one of the most important components of the earth s climate system for this they compared the results from two other dynamical cores of cam4 the finite volume fv and eulerian eul instantaneous features of rainfall in homme are similar to fv and eul similar to eul and fv homme simulates a single peak intertropical convergence zone itcz over the equator the strength of the itcz is found to be almost the same in homme and eul but more in fv it is ob

oligo miocene rotation of sardinia kar ages and paleomagnetic data of tertiary volcanics abstract conventional k ar dating was carried out on mineral separates mostly plagioclases from middle tertiary volcanics of sardinia along with paleomagnetic studies the close agreement of dates from the two methods establishes the rotation age of sardinia relative to europe within a rather short time span of 1 5 ma between 20 5 and 19 ma from correlation of our results with the geomagnetic time scale it is suggested that the rotation took place shortly after the magnetic anomaly 6

the messinian salinity crisis past and future of a great challenge for marine sciences forty years after the image of the mediterranean transformed into a giant salty lake was first conceived the fascinating history of the messinian salinity crisis msc still arouses great interest across a large and diverse scientific community early outcrop studies which identified severe palaeoenvironmental changes affecting the circum mediterranean at the end of the miocene were followed by investigations of the marine geology during the 1950s to 1970s these were fundamental to understanding the true scale and importance of the messinian event now after a long period of debate over several entrenched but largely untested hypotheses a unifying stratigraphic framework of msc events has been constructed this scenario is derived mainly from onshore data and observations but incorporates different perspectives for the offshore and provides hypotheses that can be tested by drilling the deep mediterranean basins the msc was an ecological crisis induced by a powerful combination of geodynamic and climatic drivers which had a great impact on the subsequent geological history of the mediterranean area and on the salinity of the global oceans these changed the mediterranean s connections with both the atlantic ocean and the freshwater paratethyan basins causing high amplitude fluctuations in the hydrology of the mediterranean the msc developed in three main stages each of them characterized by different palaeoenvironmental conditions during the first stage evaporites precipitated in shallow sub basins the msc peaked in the second stage when evaporite precipitation shifted to the deepest depocentres and the third stage was characterized by large scale environmental fluctuations in a mediterranean transformed into a brackish water lake the very high resolution timescale available for some late miocene intervals in the mediterranean makes it possible to consider environmental variability on extremely short time scales including in some places annual changes despite this fundamental questions remain some of which could be answered through new cores from the deepest mediterranean basins improvements in seismic imaging and drilling techniques over the last few decades make it possible to plan to core the entire basinal messinian succession for the first time the resulting data would allow us to decipher the causes of this extreme environmental change and its global scale consequences

heat flow in the western mediterranean thermal anomalies on the margins the seafloor and the transfer zones the western mediterranean basin has been formed by miocene back arc extension and is underlain by a thin and young lithosphere this young lithosphere is warm as testified by an overall elevated offshore heat flow heat flow within the western mediterranean is however highly variable and existing data are unevenly distributed and poorly studied in the central part of the liguro provencal and algero balearic basins this central part is floored by a young oceanic crust bordered by different continental margins cut by transform faults and filled by up to 8 km of sediments we present a total of 148 new heat flow data collected during the medsalt and westmedflux cruises in 2015 and 2016 and aligned along seven regional profiles that show an important heat flow variability on the basin scale but also locally on the margins a new heat flow map for the western mediterranean outlines the following regional features 1 a higher average heat flow in the algero balearic basin compared to the liguro provencal basin 94 13 mw m2 and 78 16 mw m2 respectively and 2 a regional thermal asymmetry in both basins but with opposed heat flow trends up to 20 of this heat flow difference can be explained by sediment blanketing but age and heterogeneity of ocean crust due to an asymmetric and polyphased opening of the basins are believed to have given the major thermal imprint estimates of the age of the oceanic crust based on the new heat flow suggest a considerably younger west algerian basin 16 23 ma compared to the east algerian basin and the west sardinia oceanic floor 31 37 ma on the margins and ocean continent transitions of the western mediterranean the new heat flow data point out the existence of two types of local anomalies length scale 5 30 km 1 locally increased heat flow up to 153 mw m2 on the gulf of lion margin results from thermal refraction of large salt diapirs and 2 the co existing of both low 110 mw m2 heat flow areas on the south balearic margin suggests a heat redistribution system we suspect the lateral heat advection is resulting from a regional fluid circulation in the sediments associated to the widespread plio pleistocene volcanism on the south balearic margin

field evaluation of methods for determining hydraulic conductivity from grain size data summary determination of hydraulic conductivity k and its variation in space is often a major objective of hydrogeological site investigations however measurement of k at a high spatial resolution in sedimentary aquifers is a challenge there are a number of field methods that can be used to determine k although they differ greatly in terms of their spatial resolution one commonly used approach is to estimate k from grain size analyses but the reliability of the resulting k estimates is unclear the aims of this study are to compare frequently used formulas for the determination of k from grain size data for a broad range of sediment types and to evaluate how well these methods predict k sonic sampling was used to obtain minimally disturbed cores in a highly heterogeneous sedimentary aquifer and k values of grain size analyses from 108 core samples were calculated despite the high correlation of calculated k derived from different formulas mean k values differed by several orders of magnitude between the formulas for the evaluation of the reliability of the k estimates high resolution direct push slug tests dpsts were also performed in the close vicinity of the cores a high correlation between ln k dpst and ln k grain size was found for most of the applied formulas nevertheless sample heterogeneity i e the presence of small clay layers in a generally highly permeable sample led to k grain size estimates that were significantly smaller than the k dpst estimates based on these results the applied formulas appear to be suitable for an initial assessment of aquifer k however considering the difference in calculated k mean values results are not sufficiently reliable for the high resolution analyses of k variations needed for flow or transport modeling

permeability underpressures and convection in the oceanic crust near the costa rica rift eastern equatorial pacific in situ permeability and pore pressures were measured 200 m deep beneath the top of the oceanic crust at dsdp site 504b these measurements have relevance for the transition from convective to conductive heat flow on the south flank of the costa rica rift conventional slug and constant rate injection tests were made below a hydraulic packer set at various depths in the hole the packer was first set in a massive flow unit 37 m below the sediment basement interface the bulk permeability of the 172 5 m of pillow basalts and basaltic flows below the packer was found to be about 40 millidarcys 4 10 10 cm2 measurements over 3 and 15 m intervals at the bottom of the hole in an altered pillow zone indicated a bulk permeability of 2 4 millidarcys these values are thought to be accurate to 30 formation pore pressures were found to be approximately 8 bars 2 below hydrostatic interpretation of the data with respect to simple numerical convection models suggests that the transition from convective to conductive heat flow is controlled by the cessation of convective heat transport through the sedimentary layer rather than the cessation of convection in the sediment furthermore the agreement between observed and modeled underpressures implies that hole 504b penetrated an active ocean crustal convection system the thick sedimentary layer layers of basal chert and massive flow basalts above the layer 2a pillow flows apparently form an impermeable lid effectively isolating the convection system from the ocean

morphostructure growth patterns and tectonic control of the rhone and nile deep sea fans a comparison the rhone and the nile rivers shape the sediment distribution of the ligurian and the levantine basins in the mediterranean sea respectively both rivers cut huge canyons in their bed rock during the messinian desiccation of the mediterranean and the subsequent early pliocene marine transgression reached far inland both in france and in egypt the sediment supply of both rivers was affected by climatic variations during the pleistocene but whereas glacial periods were associated with reduced water flow in the rhone they can be correlated with enhanced flow of the nile the sediment distribution and accumulation patterns of both rivers built large deltas on their continental shelves during high sea level stands during lowstands both rivers flowed as far as the shelf e ge and transported their sedimentary load through the continental slopes directly to their deep sea fans the patterns of sediment distribution and accumulation in the marine basins of the ligurian and the levantine seas were affected also by pliocene quaternary tectonic activity and halokinetic offsets that led to sediment instability the present hydrographic and sedimentological regimes of both rivers do not represent their natural potential due to artificial interference the principal economic significance of the deep sea fan accumulation process is the transportation of medium and coarse grained sediments into the deep marine basin considering the effect of these sediments on stratal permeabilities and hydrocarbon potential the presented comparative overview emphasizes recent and subrecent sedimentological aspects that are critical to petroleum exploration in active and extinct deep sea depositional environments

chronology causes and progression of the messinian salinity crisis the messinian salinity crisis is widely regarded as one of the most dramatic episodes of oceanic change of the past 20 or so million years 1 3 earliest explanations were that extremely thick evaporites were deposited in a deep and desiccated mediterranean basin that had been repeatedly isolated from the atlantic ocean1 2 but elucidation of the causes of the isolation whether driven largely by glacio eustatic or tectonic processes have been hampered by the absence of an accurate time frame here we present an astronomically calibrated chronology for the mediterranean messinian age based on an integrated high resolution stratigraphy and tuning of sedimentary cycle patterns to variations in the earth s orbital parameters we show that the onset of the messinian salinity crisis is synchronous over the entire mediterranean basin dated at 5 96 0 02 million years ago isolation from the atlantic ocean was established between 5 59 and 5 33 million years ago causing a large fall in mediterranean water level followed by erosion 5 59 5 50 million years ago and deposition 5 50 5 33 million years ago of non marine sediments in a large lago mare lake sea basin cyclic evaporite deposition is almost entirely related to circum mediterranean climate changes driven by changes in the earth s precession and not to obliquity induced glacio eustatic sea level changes we argue in favour of a dominantly tectonic origin for the messinian salinity crisis although its exact timing may well have been controlled by the 400 kyr component of the earth s eccentricity cycle

enkf coupled with groundwater flow moment equations applied to lauswiesen aquifer germany summary we describe a field application of a new data assimilation method recently proposed by panzeri et al 2013 2014 the method couples a modified ensemble kalman filter enkf algorithm with stochastic moment equations mes governing space time variations of theoretical ensemble mean and covariance values of groundwater flow state variables hydraulic heads and fluxes whereas traditional enkf entails monte carlo mc simulations and suffers from inbreeding our approach obviates both synthetic case studies have shown the me based approach to be computationally efficient and accurate when compared to mc based results here we use our me based method to assimilate drawdown data recorded during cross hole pumping tests in the heterogeneous alluvial lauswiesen aquifer near tubingen germany our results include an estimate of log transmissivity distribution throughout the aquifer and corresponding measures of estimation error we validate our calibrated model by using it to predict drawdowns recorded during another pumping test at the site and compare its performance with that of standard mc based enkf

erosional processes and paleo environmental changes in the western gulf of lions sw france during the messinian salinity crisis abstract current interpretation of the messinian salinity crisis msc involves partial desiccation of the mediterranean sea coupled with the deposition of thick evaporites in the deep basins new sets of seismic reflection profiles in the western part of the gulf of lions confirm the basinward extension of the messinian erosion and enable the mapping of distinctive seismic markers indicating the messinian erosional surface or messinian unconformity the basin margin detrital deposits and the deep evaporite sequence the geometrical relationship between these three elements and their relationship to the paleogeography of the margin during the msc provide new information about the evolution of the study area during the messinian the messinian erosional surface mes commonly correlated with the desiccation phase and the deposition of deep evaporites during the apogee of the event is generally interpreted as a subaerial feature in the gulf of lions it is a complex diachronic polygenic erosional surface observed at the base of the prograding plio quaternary sequence beneath the shelf and slope it extends downslope beneath the deep basin upper evaporites and the salt and possibly correlates conformably with the base of the so called deep lower evaporites the whole morphology of the mes reflects a buried drainage pattern supporting the interpretation of fluvial erosion driven by a substantial drop in sea level our results also suggest that large submarine gravity flows occurred prior to any significant accumulation of salt in the basin and prior to the upper evaporites consequently interbedded clastic deposits may partly account for the parallel reflectors of the lower evaporites since river erosion persisted throughout the msc the salt and upper evaporite units may also contain a large amount of detrital sediments the good quality of the new seismic data clearly reveals fan shaped messinian deposits in the downstream part of the main messinian valleys i e the nile var and spanish rivers the depositional scenarios generally involve a substantial sea level fall coupled with deltaic prodeltaic accumulations a chaotic seismic unit unit d filling messinian lows and extending beneath the salt within the study area is interpreted as a messinian clastic unit we propose a polyphase scenario of detrital fan deposition involving pre syn and post salt deposition in subaqueous subaerial environments in the gulf of lions a late miocene tectonic phase that affected the western shelf also played an important role in controlling a the pattern of the messinian fluvial network b the location of maximum erosion on the shelf and c the location of the detrital fan depocentre downslope

high resolution aquifer characterization using crosshole gpr full waveform tomography comparison with direct push and tracer test data limited knowledge about the spatial distribution of aquifer properties typically constrains our ability to predict subsurface flow and transport here we investigate the value of using high resolution full waveform inversion of cross borehole ground penetrating radar gpr data for aquifer characterization by stitching together gpr tomograms from multiple adjacent crosshole planes we are able to image with a decimeter scale resolution the dielectric permittivity and electrical conductivity of an alluvial aquifer along cross sections of 50 m length and 10 m depth a logistic regression model is employed to predict the spatial distribution of lithological facies on the basis of the gpr results vertical profiles of porosity and hydraulic conductivity from direct push flowmeter and grain size data suggest that the gpr predicted facies classification is meaningful with regard to porosity and hydraulic conductivity even though the distributions of individual facies show some overlap and the absolute hydraulic conductivities from the different methods direct push flowmeter grain size differ up to approximately one order of magnitude comparison of the gpr predicted facies architecture with tracer test data suggests that the plume splitting observed in a tracer experiment was caused by a hydraulically low conductive sand layer with a thickness of only a few decimeters because this sand layer is identified by gpr full waveform inversion but not by conventional gpr ray based inversion we conclude that the improvement in spatial resolution due to full waveform inversion is crucial to detect small scale aquifer structures that are highly relevant for solute transport

analytical models of slug tests in the present paper attempts are made to develop solutions to various models of slug tests that may be applicable in analyzing the results of such tests where existing solutions are inadequate various geometries that may be encountered in heterogeneous systems such as fractured rocks are considered solutions are presented for linear flow radial flow with boundaries two layer and concentric composite models with different flow geometries between the inner and outer region solutions are obtained in laplace space and inverted back to real space numerically type curves are presented for each solution analyses of the type curves and derivative response curves reveal that many curves have unique shapes only for certain combination of the flow parameters and the distance other sets of type curves are similar in shape although log log plots and derivative plots may emphasize some features that may not be apparent in semilog plots these results show that slug tests suffer problems of nonuniqueness to a greater extent than other well tests

simulation of monsoon intraseasonal oscillations in a coarse resolution aquaplanet gcm the skill of the global climate models gcms to realistically simulate the monsoon intraseasonal oscillations misos is related to the sensitivity of their convective parameterization schemes here we show that by coupling a simple multicloud parameterization to a coarse resolution aquaplanet gcm realistic misos can be simulated we conduct three different simulations with a fixed nonhomogeneous sea surface temperature mimicking the indian ocean western pacific warm pool wp centered at the three latitudes 5 n 10 n and 15 n respectively to replicate the seasonal migration of the tropical convergence zone tcz this results in the generation of mean circulation resembling the monsoonal flow pattern in boreal summer succession of eastward propagating madden julian oscillation mjo disturbances with phase speed amplitude and structure similar to summer mjos are simulated when the wp is at 5 n when the wp is located over 10 n northward and eastward propagating misos are simulated this case captures the meridional seesaw of convection between continental and oceanic tcz observed during boreal summer over south asia westward propagating rossby wave like disturbances are simulated when the wp is over 15 n congruous with the synoptic disturbances seen over the monsoon trough the initiation of intraseasonal oscillations in the model can occur internally through organization of convective events above the wp associated with internal dynamics

field characterization and data integration to define the hydraulic heterogeneity of a shallow granular aquifer at a sub watershed scale providing a sound basis for aquifer management or remediation requires that hydrogeological investigations carried out to understand groundwater flow and contaminant transport be based on representative data that capture the heterogeneous spatial distribution of aquifer hydraulic properties this paper describes a general workflow allowing the characterization of the heterogeneity of the hydraulic properties of granular aquifers at an intermediate scale of a few km2 the workflow involves characterization and data integration steps that were applied on a 12 km2 study area encompassing a decommissioned landfill emitting a leachate plume and its main surface water receptors the sediments composing the aquifer were deposited in a littoral sublittoral environment and show evidence of small scale transitional heterogeneities cone penetrometer tests cpt combined with soil moisture and electrical resistivity smr measurements were thus used to identify and characterize spatial heterogeneities in hydraulic properties over the study area site specific statistical relationships were needed to infer hydrofacies units and to estimate hydraulic properties from high resolution cpt smr soundings distributed all over the study area a learning machine approach was used due to the complex statistical relationships between colocated hydraulic and cpt smr data covering the full range of aquifer materials application of this workflow allowed the identification of hydrofacies units and the estimation of horizontal hydraulic conductivity vertical hydraulic conductivity and porosity over the study area the paper describes and discusses data acquisition and integration methodologies that can be adapted to different field situations while making the aquifer characterization process more time efficient and less labor intensive

the catalan margin during the messinian salinity crisis physiography morphology and sedimentary record abstract the messinian salinity crisis msc drastically affected the physiography morphology and sedimentation all along the mediterranean area at the end of the miocene this paper presents an analysis of the effects of the msc on the catalan continental margin based on a broad database of seismic reflection profiles from the oil industry and academy we study the sedimentary processes and their controlling factors and the correlation with the nearby and well known gulf of lions because of the complexity of the msc we define the margin erosion surface top erosion surface mes tes as the surface marking the end of the messinian event which allows differentiating three domains along the catalan margin the creus girona and barcelona domains separated by the palamos and blanes canyons the creus domain shows an important structural control on the mes tes physiography while the girona and barcelona domains are characterized by wide and flat msc platforms below the present day shelf the entire margin developed a series of complex drainage systems as the result of the messinian sea level drop the location of the main valleys cap de creus paleo drainage system palamos and blanes paleo canyons and the downslope trending valleys on the barcelona domain was directly controlled by the structural framework in contrast the barcelona paleo drainage system and the tributaries of the blanes and palamos systems were excavated by direct subaerial erosion by meteoric rain in the basins limited by basement blocks and were afterwards totally filled by the pliocene quaternary sedimentation regarding the msc depositional features the major part of the eroded sediment was deposited as detrital deposits on the foot of the slope the distribution of detrital bodies and evaporites was also structurally controlled a zanclean sea level rise occurring in at least two phases is confirmed by this study in correlation with interpretations from the gulf of lions

sea valleys and related depositional systems in the gulf of lion and ebro continental margins 1 four main types of sea valleys submarine canyons gullies channels of turbidite systems and a mid ocean channel have been characterized in the ebro and the gulf of lion distal margins in the catalan sea together with three main types of depositional bodies pyrenean canyon deep sedimentary body pcdsb apron deposits and channel levee complexes related to the development of these sea valleys erosion and deposition mainly during the quaternary have formed the majority of these sea valleys although some structurally controlled sea valleys also exist as an example a messinian entrenchment has been confirmed in the petit rhone canyon the evolution of the drainage patterns is established from the detailed analysis of the sedimentary structure this analysis revea s the presence of buried sedimentary bodies and older drainage systems differing from those observed in the bathymetric charts specific factors determine the evolutionary differences between both margins including the absence or presence of underlying evaporitic messinian layers and the regional geodynamic evolution during and after the alpine orogeny we propose a dual evolutionary model from the end of the miocene to the quaternary

the impeller meter for measuring aquifer permeability variations evaluation and comparison with other tests a knowledge of the variation of horizontal hydraulic conductivity with vertical position k z is important in understanding the transport and dispersive properties of aquifers using an impeller meter to measure the discharge distribution in a screened well while pumping at a constant rate is a promising technique for obtaining the k z function such an application is described herein and the resulting k z functions are compared with those obtained previously using tracer tests and multilevel slug tests impeller meter data were the most convenient to obtain and tracer data the most difficult the k z functions obtained by the three methods were not identical but quite similar overall this similarity between both borehole tests and the larger scale tracer test showed that nonstationary hydraulic conductivity trends in a stochastic hydrologic sense exist in the test aquifer the impeller meter method was better able to detect the higher k layers than was the multilevel slug approach overall the results suggest that a practical strategy for fitting impeller meter tracer or multilevel slug test data to a given aquifer is to use the selected testing procedure to obtain a dimensionless distribution and then a standard pumping test to measure combining both types of information enables dimensional values for k z to be calculated in low permeability aquifers or near the bottom of a test well the fluid velocity due to pumping may be below the stall velocity of an impeller thus there is a definite need for the commercial development of more sensitive flow measuring devices such as heat pulse flowmeters hess 1986 which will extend the resolution of this field method

analytic representation of the large scale organization of tropical convection the pivotal role of mesoscale organization on the large scale coherence of tropical convection is represented by a nonlinear dynamical model the general model consists of two interlocked systems a mesoscale parameterization of organized convection and a two layer model of large scale equatorial dynamics the lower layer dynamics is rossby gyre like whereas outflow from organized convection maintains the upper layer circulation the transports of zonal momentum in the vertical and meridional directions are key processes an archetype of the general model in spite of being brutally simplified represents the convective organization momentum transport and equatorial superrotation realized by the cloud resolving convection parameterization or superparameterization explicit approach developed by grabowski the mesoscale parameterization is an analytic equivalent of the cloud system resolving models used in this computational approach finally issues in parameterizing convective organization are discussed

mesoscale organization and cloud microphysics in a bay of bengal depression abstract airborne radar and cloud microphysical data were obtained throughout a monsoon depression observed over the bay of bengal on 3 8 july 1979 during the summer monsoon experiment of the global atmospheric research programme the precipitation in the disturbance occurred in mesoscale rain areas 100 300 km in horizontal dimension with the largest areas tending to be elongated in the east west or northwest southeast direction these mesoscale precipitation features resembled the rain areas of equatorial cloud clusters each mesoscale precipitation feature contained intense convective cells but the area covered by rain was predominantly stratiform the convective cells in the mesoscale features were sometimes arranged in rapidly moving rather narrow arc shaped east west lines with the stratiform precipitation trailing the line in other cases the convective cells were more randomly embedded in the stratiform rain ice particle images obtained at flight level temperatures of 5 to 25 c indicated the

the role of tilted heating in the evolution of the mjo there has been much discussion about the role of tilted heating in the evolution of the mjo it is believed that the inability of many general circulation models to produce a robust mjo is directly related to deficiencies in the model produced tropical heating distributions given the mjo s importance in tropical climate we need to better understand what heating distributions are required in climate models to produce strong mjos this study addresses the role of tilted heating in the community atmospheric model version 4 cam4 idealized and observed heating distributions are added to the tropical atmosphere in cam4 these include heating that tilts westward with height in the lower and upper atmosphere as well as various tilted and untilted heating in the form of either idealized blobs or observations derived from the tropical rainfall measuring mission precipitation radar and the international satellite cloud climatology project we find that low level heating ahead of the mjo convective center is critical for the initial strengthening and later maintenance of the mjo however tilted heating is not necessary to simulate a realistic mjo in addition excess upper level heating whether tilted or not appears to degrade the mjo signal although rossby wave modes are evident only in runs with additional upper level heating kelvin waves are evident during strong mjos for all simulations but are only visible over the central pacific results suggest that accurate shallow convective parameterizations may be more important than deep convective ones in the evolution of the mjo

recent sedimentary events in the western gulf of lions western mediterranean abstract analysis of very high resolution data 3 5 khz profiles and em12d acoustic imagery collected during the calmar catalono languedocian margin cruise 1997 highlighted the occurrence of two very recent but previously unknown erosional sedimentary events on the continental rise between the rhone fan and the pyreneo languedocian ridge these events preserved as unconformable very thin lobes observable on acoustic imagery but not on 3 5 khz echo soundings relate to erosional processes linked to near bottom currents that seem to characterize the holocene hydrodynamical conditions in the deep gulf of lions they follow a pleistocene regime when gravity sedimentation dominated on the gulf of lions margin either through aggradational turbidite deposition rhone fan and pyreneo languedocian ridge or through remobilization of sediments by regional mass movements processes

a global climatology of monsoon low pressure systems the first global climatology of monsoon low pressure systems is presented here based on the era interim reanalysis low pressure systems are classified into three intensity categories and particular focus is given to systems in the category corresponding to a traditional definition of monsoon depressions vortex tracks are identified using an automated algorithm applied to the distributions of 850 hpa relative vorticity sea level pressure and surface wind speed for 1979 2012 roughly two to three times as many monsoon low pressure systems form in the northern hemisphere as in the southern hemisphere during local summer the frequency of genesis typically peaks in local summer but low pressure systems form throughout the year in every monsoon region interannual variability is weak with standard deviations of summer counts typically being below 10 of the long term summer mean regional composites reveal that monsoon depressions in india the western pacific and northern australia share a common structure consisting of a warm over cold core and a top heavy column of potential vorticity that extends from the surface to the upper troposphere a separate class of monsoon low pressure systems develops over dry regions of west africa and western australia with a shallow composite structure having a warm core in the lower troposphere and cyclonic potential vorticity confined to a thin near surface layer low pressure systems in nearly all monsoon regions are estimated to account for a large fraction from about 40 to more than 80 of summer precipitation on the poleward edge of the climatological mean precipitation maxima

role of stratiform rainfall in modifying the northward propagation of monsoon intraseasonal oscillation 1 the stratiform and convective rain rate measurement from the tropical rainfall measuring mission trmm satellite data can give a realistic idea of the latent heating distribution in the tropics the vertical profile of diabatic heating related to the convective and the stratiform rain is known to modulate the dynamical response of atmosphere and also the vertical structure of madden julian oscillation in this study the contribution of the stratiform and convective rain rate to the total rain rate during different phases of the northward propagating boreal summer monsoon intraseasonal oscillation iso is examined using the trmm data two new insights have emerged from this analysis first unlike conventional wisdom the convective component shows weak northward propagation and grows and decays in situ during the evolution of active and break phases while the northward propagation of the monsoon iso is largely achieved by organized movement of the stratiform component second the trademark meridional dipole pattern of total rainfall between the monsoon trough zone and the southern equatorial indian ocean also arises largely from the contribution of stratiform anomalies as the northward propagation of the monsoon iso is known to be due to the anomalous response of the atmosphere to heating in the presence of mean easterly vertical shear modification of the vertical profile of heating due to a contribution from stratiform rain could influence the northward propagation of the monsoon iso this hypothesis is tested using a simple global atmospheric circulation model to study the response of the convective and stratiform heating profiles on the modification of the mean condition modification in the large scale response of the atmosphere as a result of proper specification of convective and stratiform heating anomalies indicates that the presence of stratiform heating favors the northward propagation of the heat source thereby facilitating the positive feedback leading to northward propagation of the monsoon iso these results underline the importance of simulating the partitioning of convective and stratiform rain by cumulus parameterization in climate models if they have to get the space time structure of the summer isos correct

gravity waves in shear and implications for organized convection abstract it is known that gravity waves in the troposphere which are often excited by preexisting convection can favor or suppress the formation of new convection here it is shown that in the presence of wind shear or barotropic wind the gravity waves can create a more favorable environment on one side of preexisting convection than the other side both the nonlinear and linear analytic models developed here show that the greatest difference in favorability between the two sides is created by jet shears and little or no difference in favorability is created by wind profiles with shear at low levels and no shear in the upper troposphere a nonzero barotropic wind or equivalently a propagating heat source is shown to also affect the favorability on each side of the preexisting convection it is shown that these main features are captured by linear theory and advection by the background wind is the main physical mechanism at work these processes should play an important role in the organization of

geostatistical analysis of centimeter scale hydraulic conductivity variations at the made site 1 spatial variations in hydraulic conductivity k provide critical controls on solute transport in the subsurface recently new direct push tools were developed for high resolution characterization of k variations in unconsolidated settings these tools were applied to obtain 58 profiles vertical resolution of 1 5 cm from the heavily studied macrodispersion experiment made site we compare the data from these 58 profiles with those from the 67 flowmeter profiles that have served as the primary basis for characterizing the heterogeneous aquifer at the site overall the patterns of variation displayed by the two data sets are quite similar in terms of both large scale structure and autocorrelation characteristics the direct push k values are on average roughly a factor of 5 lower than the flowmeter values this discrepancy appears to be attributable at least in part to opposite biases between the two methods with the current versions of the direct push tools underestimating k in the highly permeable upper portions of the aquifer and the flowmeter overestimating k in the less permeable lower portions the vertically averaged k values from a series of direct push profiles in the vicinity of two pumping tests at the site are consistent with the k estimates from those tests providing evidence that the direct push estimates are of a reasonable magnitude the results of this field demonstration show that direct push profiling has the potential to characterize highly heterogeneous aquifers with a speed and resolution that has not previously been possible

a mini slug test method for determination of a local hydraulic conductivity of an unconfined sandy aquifer abstract a new and efficient mini slug test method for the determination of local hydraulic conductivities in unconfined sandy aquifers is developed the slug test is performed in a small diameter 1 inch driven well with a 0 25 m screen just above the drive point the screened drive point can be driven from level to level and thereby establish vertical profiles of the hydraulic conductivity the head data from the test well are recorded with a 10 mm pressure transducer and the initial head difference required is established by a small vacuum pump the method described has provided 274 spatially distributed measurements of a local hydraulic conductivity at a tracer test site at vejen denmark the mini slug test results calculated by a modified dax slug test analysing method applying the elastic storativity in the dax equations instead of the specific yield are in good accordance with the results from two natural gradient tracer experiments performed at the test site the original dax the bouwer and rice and the chirlin analysing methods all led to an underestimation of the effective hydraulic conductivity by a factor of more than 2 when compared with the tracer tests in contrast the spherical flow model of karasaki et al overestimated the results of the tracer tests by approximately a factor 1 4 the dax and the cooper et al methods assuming only radial flow to the partially screened well yielded a better approximation of the horizontal hydraulic conductivity than the chirlin method which also considers axial flow this fact is suggested to be a result of aquifer anisotropy as a significant higher horizontal than vertical hydraulic conductivity may suppress the significance of the axial flow component

multicloud models for organized tropical convection enhanced congestus heating abstract despite the recent advances in supercomputing the current general circulation models gcms poorly represent the large scale variability associated with tropical convection multicloud model convective parameterizations based on three cloud types congestus deep and stratiform introduced recently by the authors have been revealed to be very useful in representing key features of organized convection and convectively coupled waves here a new systematic version of the multicloud models is developed with separate upper and lower troposphere basis functions for the congestus and stratiform clouds it naturally leads to a new convective closure for the multicloud models enhancing the congestus heating in order to better pinpoint the congestus preconditioning and moistening mechanisms the models are studied here for flows above the equator without rotation effects first the new model results consist of the usual synoptic scale convectively coupled moist gravity wave packets moving at 15 20 m

salt flow by aggrading and prograding overburdens the mechanisms responsible for segmentation of salt sheets and their emplacement into higher stratigraphic levels are not separable and act simultaneously three sets of centrifuge models with strongly planar anisotropic anisotropy the ratio between the effective viscosities in pure and simple shear ranging between 4 8 and 16 4 microlaminate overburdens are used to study the effect of aggradation and progradation on segmentation and emplacement of allochthonous salt sheets in the first set of models a tabular buoyant source layer was overlain by tabular anisotropic overburden simulating aggradation during centrifuging the underlying ductile source layer was segmented into individual wall like diapirs by the subsiding blocks formed due to extension and faulting of the overburden the extensional zone in these models started at the spreading edge free face of the model and migrated backwards in the second set of models a tabular buoyant source layer was overlain successively by wedges of anisotropic overburdens simulating progradation during centrifuging the buoyant layer was displaced from the back of the model where loading was higher towards the free face in the front of the model where overburden units were thinner overburden units extended at the back and the middle of the model while contractional structures dominated at the front where asymmetric diapirs formed overhangs that spread basinward to form salt sheets in the third set of models a wedge shaped buoyant source layer was overlain successively by wedges of anisotropic overburden simulating progradation the overburden wedge created a lateral pressure gradient ranging from 144 pa at the back of the model to 80 pa at the front when deformed in the centrifuge in these models as in the second set of models the underlying buoyant mass was displaced basinward by the subsiding thicker overburden units at the back of the model contractional structures dominated the deformation at the leading edge of the wedge comparison of model results suggests that progradation as in the second and third sets of models loads underlying salt differentially displaces it downdip and segments it as it segments at the back the salt flows laterally to areas of lower loading by intruding through the thinner overburden units and forming secondary salt sheets at the front on the other hand aggradation of uniform overburden segments a buoyant sheet into two dimensional salt walls or stocks as in the first set of models

the mjo and convectively coupled waves in a coarse resolution gcm with a simple multicloud parameterization abstract the adequate representation of the dominant intraseasonal and synoptic scale variability in the tropics characterized by the madden julian oscillation mjo and convectively coupled waves is still problematic in current operational general circulation models gcms here results are presented using the next generation ncar gcm the high order methods modeling environment homme as a dry dynamical core at a coarse resolution of about 167 km coupled to a simple multicloud parameterization the coupling is performed through a judicious choice of heating vertical profiles for the three cloud types congestus deep and stratiform that characterize organized tropical convection important control parameters that affect the types of waves that emerge are the background vertical gradient of the moisture and the stratiform fraction in the multicloud parameterization which set the strength of large scale moisture convergence and unsaturated downdrafts in the wake of deep convection respectively three

gregarious tropical convection abstract a beat source with a vertical profile like that of observed tropical mesoscale convective systems mcss is shown to cause through inviscid gravity wave dynamics upward displacement at low levels in a mesoscale region surrounding the heating typical values are 10 30 area contraction at the surface everywhere within 270 km of the heating 6 h after it starts as a result conditions near an existing mcs but beyond the area of mcs outflow become more favorable for the development of additional convection this theory predicts that cloud clusters should be gregarious infrared satellite imagery confirms that almost half of the cold cloudiness observed in a month over the oceanic warm pool region was contributed by just 14 objectively defined multiday supercluters

overpressure within upper continental slope sediments from cptu data gulf of lion nw mediterranean sea data from in situ piezocone tests cptu and laboratory analyses are utilized for the interpretation of the stress history of quaternary sedimentary sequences in the upper continental slope of the gulf of lion northwestern mediterranean sea a cptu based preconsolidation pressure profile referenced to the current effective stress indicates that the deposit is underconsolidated from 12 meters below the seafloor mbsf down to at least 150 mbsf excess pore pressure below 12 mbsf is further supported by results from oedometer and dissipation tests subseafloor pockmarks and indications of free gas in seismic reflection profiles reveal four main overpressure sources si siv with overpressure ratios 0 3 at subseafloor depths coinciding with levels where the dominantly silty clayey sediment contains increased proportions of sand we relate the excess pore pressure related to free gas due to gas exsolution processes and sea level variations driven by pleistocene sea level changes

implications of salt sediment interactions on the architecture of the gulf of lions deep water sedimentary systems western mediterranean sea we integrated structural analysis of multichannel seismic data and isopach maps of the quaternary sedimentary cover to evaluate how salt tectonics has influenced the stratigraphic evolution offshore the gulf of lions the interplay between salt tectonics and sedimentation occurs at two scales at local scale listric normal faults create bathymetric relief able to deviate sediment transport axes with implications on depocenters configuration at depocenter scale overburden vertical movements due to salt evacuation or salt diapiric rise create sub basins providing accommodation space for clastic deposition these mechanisms have significant implications on the architecture and the internal organization of turbidite systems offshore the gulf of lions

effect of stratiform heating on the planetary scale organization of tropical convection abstractit is widely recognized that stratiform heating contributes significantly to tropical rainfall and to the dynamics of tropical convective systems by inducing a front to rear tilt in the heating profile precipitating stratiform anvils that form from deep convection play a central role in the dynamics of tropical mesoscale convective systems the wide spreading of downdrafts that are induced by the evaporation of stratiform rain and originate from in the lower troposphere strengthens the recirculation of subsiding air in the neighborhood of the convection center and triggers cold pools and gravity currents in the boundary layer leading to further lifting here aquaplanet simulations with a warm pool like surface forcing based on a coarse resolution gcm of approximately 170 km grid mesh coupled with a stochastic multicloud parameterization are used to demonstrate the importance of stratiform heating for the organization of convection on planetary and intraseasonal scales when the model paramet

role of stratiform heating on the organization of convection over the monsoon trough it has been recently demonstrated that stratiform heating plays a critical role in the scale selection of organized tropical convection in an aquaplanet version of a coarse resolution atmospheric general circulation model coupled to a stochastic multicloud cumulus parameterization scheme it is shown that madden julian oscillation like organization dominates when the model is tuned to produce strong and long lived stratiform heating while it gives rise to mostly convectively coupled waves in the case of weak and short lived stratiform clouds the study is extended here to the case of an asymmetric forcing mimicking the migration of the intertropical convergence zone itcz during summer to understand the impact of changes in stratiform heating on the monsoon dynamics consistent with the equatorial itcz case strong and long lived stratiform heating promotes northward and eastward moving intraseasonal disturbances while weak and short lived stratiform heating yields mostly westward propgating synoptic scale low pressure systems moreover the underlying intraseasonal versus low pressure system activity seems to impact the strength and extend of the monsoon trough mt in the regime with intraseasonal activity the mt is much stronger and extends northward while in the low pressure system case mt is some what weaker in strength but extends further westward in the low pressure dominated regime the background vorticity and zonal wind profiles over the monsoon trough are consistent with the observations

the usefulness of outcrop analogue air permeameter measurements for analyzing aquifer heterogeneity quantifying outcrop hydraulic conductivity and its spatial variability saturated hydraulic conductivity k is one of the most important parameters determining groundwater flow and contaminant transport in both unsaturated and saturated porous media although several well established laboratory methods exist for determining k in situ measurements of this parameter remain very complex and scale dependent often the limited accessibility of subsurface sediments for sampling means an additional impediment to our ability to quantify subsurface k heterogeneity one potential solution is the use of outcrops as analogues for subsurface sediments this paper investigates the use of air permeameter measurements on outcrops of unconsolidated sediments to quantify k and its spatial heterogeneity on a broad range of sediment types the neogene aquifer in northern belgium is used as a case study for this purpose to characterize the variability in k 511 small scale air permeability measurements were performed on outcrop sediments representative over five of the aquifer s lithostratigraphic units from these measurements outcrop scale equivalent k tensors were calculated using numerical upscaling techniques validation of the air permeameter based k values by comparison with laboratory constant head k measurements reveals a correlation of 0 93 overall the results indicate that hand held air permeameters are very efficient and accurate tools to characterize saturated k as well as its small scale variability and anisotropy on a broad range of unconsolidated sediments the studied outcrops further provided a qualitative understanding of aquifer hydrostratigraphy and quantitative estimates about k variability at the centimetre scale to metre scale copyright 2013 john wiley sons ltd

the mjo in a coarse resolution gcm with a stochastic multicloud parameterization abstractthe representation of the madden julian oscillation mjo is still a challenge for numerical weather prediction and general circulation models gcms because of the inadequate treatment of convection and the associated interactions across scales by the underlying cumulus parameterizations one new promising direction is the use of the stochastic multicloud model smcm that has been designed specifically to capture the missing variability due to unresolved processes of convection and their impact on the large scale flow the smcm specifically models the area fractions of the three cloud types congestus deep and stratiform that characterize organized convective systems on all scales the smcm captures the stochastic behavior of these three cloud types via a judiciously constructed markov birth death process using a particle interacting lattice model the smcm has been successfully applied for convectively coupled waves in a simplified primitive equation model and validated against radar data of

large scale natural gradient tracer test in sand and gravel cape cod massachusetts 1 experimental design and observed tracer movement a large scale natural gradient tracer experiment was conducted on cape cod massachusetts to examine the transport and dispersion of solutes in a sand and gravel aquifer the nonreactive tracer bromide and the reactive tracers lithium and molybdate were injected as a pulse in july 1985 and monitored in three dimensions as they moved as far as 280 m down gradient through an array of multilevel samplers the bromide cloud moved horizontally at a rate of 0 42 m per day it also moved downward about 4 m because of density induced sinking early in the test and accretion of areal recharge from precipitation after 200 m of transport the bromide cloud had spread more than 80 m in the direction of flow but was only 14 m wide and 4 6 m thick the lithium and molybdate clouds followed the same path as the bromide cloud but their rates of movement were retarded about 50 relative to bromide movement because of sorption onto the sediments

sea level control on turbidite activity in the rhone canyon and the upper fan during the last glacial maximum and early deglacial abstract the timing routing and processes of sediment transfer from the continents to the oceans at millennial time scale are still largely unknown the potential of turbidite systems dominantly deposited during sea level lowstands to record global or regional environmental fluctuations is usually under exploited because of the difficulty to obtain robust chronostratigraphic constraints in turbiditic deposits and therefore to tie changes in sedimentary processes to environmental fluctuations we were able to obtain a millennial scale chronostratigraphy based on oxygen isotopes of the scarce foraminifera preserved in turbiditic deposits of the rhone turbidite system within the western mediterranean our results show that 1 objective criteria can be defined for the selection of foraminifera preserved within the pelagic intervals between the turbiditic sequences in order to obtain a reliable isotope stratigraphy 2 turbidites triggered by hyperpycnal currents are described for the first time within the rhone turbidite system they are related to the periods of direct fluvial connection with the canyon head during the sea level lowstand and early rise and to a period of high sediment flux in relation to the massive recession of the rhone glaciers in the alps 3 the lithofacies change passing from hyperpycnal to bouma type is dated at ca 19 cal ka bp which might correspond to an acceleration of sea level rise 19 ka meltwater pulse