internal structure of an alpine rock glacier based on crosshole georadar traveltimes and amplitudes rapid melting of permafrost in many alpine areas has increased the probability of catastrophic rock slides in an attempt to provide critical structural information needed for the design and implementation of suitable mitigation procedures we have acquired low frequency 22 mhz cross hole radar data from within a fast moving rock glacier an important form of alpine permafrost since the ice rock and pockets of water and air found in the underground of high alpine areas have very different dielectric permittivities and electrical conductivities the radar method was well suited for investigating the structure and state of the rock glacier our interpretation of the radar velocities and attenuations was constrained by geomorphological observations borehole lithological logs and the results of a surface seismic survey the radar data revealed the existence of a discontinuous 7 11 m thick ice rich zone distinguished by high velocities 0 14 0 17 m ns and low attenuations 0 04 0 09 m 1 and a thin underlying ice free zone characterized by moderate velocities 0 11 0 12 m ns and low attenuations 0 04 0 09 m 1 beneath these two zones we observed a prominent band of high velocities 0 14 0 17 m ns and moderately high attenuations 0 10 0 20 m 1 associated with unconsolidated glacial sediments and numerous large air filled voids which in the past were probably filled with ice at greater depths the variably dry to water saturated sediments were represented by generally lower velocities 0 08 0 10 m ns and higher attenuations 0 16 0 24 m 1 the bedrock surface was represented by an abrupt 0 03 m ns velocity increase we speculate that the disappearance of ice both laterally and with depth occurred during the past one to two decades

on the use of combined geophysical methods to assess water content and water conductivity of near surface formations abstract we propose to deepen the interpretation of combined geophysical methods georadar seismic and electric to assess physical properties characterizing the near surface porous formations especially the influence of water velocity analysis of multioffset georadar data are used together with seismic methods to estimate lateral and vertical ground water fluctuations this enables us to identify transitions from non saturated to fully saturated porous layers with certainty furthermore the accurate knowledge of seismic velocities helps to estimate the porosity of the ground water formations finally we show how the radar technique may be useful in solving the problem of trade off between bulk resistivity which is deduced from electrical measurements and that of water ionic conductivity and water content these theoretical considerations are illustrated using various measurements conducted at the same test site our interpretation is compared with a few laboratory measurements on water and soil samples this study displays the impact of combined geophysical approaches for providing models of water and ionic transfers down to a depth of several metres

ocean wave slope observations using radar backscatter and laser altimeters abstract combination of laser and radar aboard an aircraft is used to directly measure long gravity wave surface tilting simultaneously with nadir viewing microwave backscatter from the sea surface the presented dataset is extensive encompassing varied wind conditions over coastal and open ocean wave regimes laser derived slope statistics and ka band 36 ghz radar backscatter are detailed separately to document their respective variations versus near surface wind speed the slope statistics measured for 1 2 m show good agreement with cox and munk s oil slickened sea measurements a notable exception is elevated distribution peakedness and an observed wind dependence in this likely proxy for nonlinear wave wave interactions aircraft ka band radar data nearly mimic ku band satellite altimeter observations in their mean wind dependence the present calibrated radar data along with relevant observational and theoretical studies suggest a large 5 db bias in previous ka band results next wave

momentum transfer over the coastal zone spatial variations of surface stress over the coastal shoaling zone are studied offshore of duck north carolina by the longez research aircraft equipped to measure both atmospheric turbulence and oceanic waves we find that the spatial variation of the friction velocity with offshore distance is much larger with offshore flow than with onshore flow in general the mean square slope of the short waves wavelength shorter than 2 m decreases with offshore distance while the mean square slope of the long waves wavelength longer than 2 m increases with offshore distance with onshore flow the friction velocity is strongly correlated with surface waves in addition the variation of the neutral drag coefficient is well correlated with the atmospheric bulk richardson number with offshore flow the observed momentum flux significantly decreases with offshore distance within the first few kilometer offshore the relationship between the friction velocity and the mean square slope of the short waves and the relationship between the neutral drag coefficient and the atmospheric bulk richardson number are obscured by the direct influence of the upstream land surface on the measured turbulence these relationships for offshore flow agree well with those for onshore flow if the fetch is beyond the immediate influence of the land surface the results in this study suggests that the effects of the strong turbulence advected from over the nearby land surface in offshore flow may lead to ambiguous physical interpretation of the correlation between the momentum flux and the wave state

the use of the natural gamma log in engineering geological investigations the natural gamma log is widely used in both cased and uncased boreholes to identify changes in lithology down the length of a borehole this is particularly important in the ground investigation process where 100 core recovery is often not achieved in the borehole programme in this paper the use of the gamma log to provide additional information from the ground investigation boreholes is examined and illustrated by a number of case histories it is shown that the gamma log can be used to study both the lithological variations within an individual borehole and changes in geological structure across a construction site it is also demonstrated that a geological formation or sequence can be classified in terms of its natural gamma signature which enables the geologist to observe its presence over large distances on a regional basis the importance of the calibration of the gamma sonde and the use of the correct logging speed is emphasised in the paper the successful calibration of the log against a quarry wall using a known observed geological structure as a reference is also described together with the use of the resulting information to obtain a geological log for boreholes drilled behind the quarry face its use in extrapolating between boreholes to detect and trace the presence of a particular geological formation to estimate its vertical and lateral extent for possible extraction is also discussed

geostatistical analysis of aquifer heterogeneity from the core scale to the basin scale a case study this study examines the spatial variability of conductivity within the sandstone wabiskaw member of the lower cretaceous middle mannville in the alberta basin the wabiskaw is an important regional hydrostratigraphic unit vertical variability within the aquifer is characterized by downhole variograms of log conductivity from core measurements they are found to exhibit pseudoperiodic structures due to alternating sand and shale layers horizontal spatial variability is characterized using variograms of log transmissivity and indicator data these variograms show a steady increase in spatial variability over length scales ranging from 400 m to 100 km characteristic of self similar or fractal behavior they also reveal distinct correlation structures related to both high and low transmissivity depositional features this study also considers the upscaling of conductivity vertically from the core to the well scale and horizontally from the well to the basin scale it is shown that traditional vertical upscaling of conductivities by arithmetic averaging causes an overestimation of transmissivity in two dimensional areal flow models an alternative approach based on power averaging is proposed transmissivities derived by vertical upscaling of core measurements are compared with values derived from drill stem tests in the same well no correlation between these quantities is observed an average transmissivity for the wabiskaw in the study area is determined by geometric spatial averaging however the highly clustered spatial distribution of well locations requires a weighting of sample values using ordinary kriging

atmospheric boundary layer adjustment to the synoptic cycle at the brazil malvinas confluence south atlantic ocean 1 this study analyzes and discusses atmospheric boundary layer vertical profiles of potential temperature specific humidity and wind speed at each of the sides of the brazil malvinas confluence in the southwestern atlantic ocean such confluence is characterized by the meeting of water masses with very different characteristics the southern waters of the malvinas current can be several degrees colder and appreciably less salty than the northern brazil current waters at the same time a synoptic cycle can be identified at the region marked by the successive passages of frontal systems and extratropical cyclones the different phases of the synoptic cycle lead to different thermal advections at the confluence causing respective different patterns of atmospheric boundary layer adjustment to the surface heterogeneity induced by the confluence in the present study this adjustment along the synoptic cycle is analyzed using data from five experiments performed across the confluence from 2003 to 2008 in each of the campaigns a number of soundings were launched from a ship at both sides of the confluence a climatological analysis with respect to the closest frontal passage is presented and it suggests that the observations collected at each of the years analyzed are referent to a different day of the synoptic cycle the average profiles at each side of the confluence are in agreement with previous modeling studies of warm and cold thermal advection patterns over an oceanic front furthermore our study shows that peculiar transitional characteristics are also observed between the conditions of well established warm and cold advection at many phases of the synoptic cycle a strongly stratified boundary layer occurs at one or both sides of the confluence some of the observed characteristics such as a large moisture accumulation near the surface suggest that existing sensible and latent heat fluxes parameterizations fail under very strong stratifications and the consequences of this deficiency are analyzed

the evolution of the southern margin of the east european craton based on seismic and potential field data abstract this paper presents an integrated geophysical study of the southern margin of the east european craton eec in the karpinksy swell north caucasus area it presents new interpretations of deep refraction and wide angle reflection deep seismic sounding dss data as well as conventional seismic and cdp profiling and new analyses of potential field data including three dimensional gravity and magnetic modelling an integrated model of the physical properties and structure of the earth s crust and partially upper mantle displays distinct features that are related to tectonic history of the study area the voronezh massif vm the ukrainian shield and rostov dome rd of the eec as well as the donbas foldbelt df karpinsky swell ks scythian plate sp and precaspian basin pcb constitute the geodynamic ensemble that developed on the southern margin of the continent baltica there proposed evolutionary model comprises a stage of rifting during the middle to late devonian post rift extension and subsidence during carboniferous early permian times synchronous with and related to the southward displacement of the rostov dome and extension in a palaeo scythian back arc basin and subsequent mesozoic and younger evolution a pre ordovician possibly riphean mafic magmatic complex is inferred on a near vertical reflection seismic cross section through the western portion of the astrakhan dome in the southwest part of the precaspian basin this complex combined with evidence of a subducting slab in the upper mantle imply the presence of pre ordovician riphean island arc with synchronous extension in a precaspian back arc basin is suggested a middle palaeozoic back arc basin ensemble in what is now the western karpinsky swell was more than 100 km to the south from its present location the stavropol high migrated northwards dislocating and moving fragments of this back arc basin sometime thereafter linear positive magnetic anomalies reflect the position of associated faults which define the location of the eastern segment of the karpinsky swell these faults which dip northward are recognised on crustal dss profiles crossing the donbas foldbelt and scythian plate they are interpreted in terms of compressional tectonics younger than the hercynian stage of evolution i e post palaeozoic

joint application of surface electrical resistivity and gpr measurements for groundwater exploration on the island of spiekeroog northern germany geophysical surveys have been carried out on the east frisian island of spiekeroog at the german north sea coast in 1996 so called freshwater lenses lying on top of saltwater saturated layers because of their lower density provide most of the freshwater supply on the frisian islands the major goal of the present study is to show the possibilities of a joint application of surface electrical resistivity soundings and ground penetrating radar gpr for the hydrogeological investigation of the island it is shown that a comprehensive interpretation of large scale gpr profiling data in a sandy aquifer provides valuable hydrogeological information especially if there is not any other information available such as from boreholes or groundwater measuring points applying the techniques of surface electrical resistivity and ground penetrating radar jointly we were able to construct a groundwater contour map for the entire island of spiekeroog in addition we were able to delineate hydrogeologically important changes in grain size and stratigraphical features and to indicate temporal changes of the spatial extent of the freshwater reservoir in comparison to earlier less complete investigations finally we located an area previously unknown in the eastern part of the island where precipitation appears to be developing a substantial new freshwater lens

quantitative integration of hydrogeophysical data conditional geostatistical simulation for characterizing heterogeneous alluvial aquifers high resolution geophysical parameter information as it can be provided for example by crosshole georadar and seismic tomography has proven to provide useful spatial information to complement traditional hydrological methods such as core analyses logging techniques and tracer or pumping tests quantitative integration of these diverse database components is one of the major challenges in the field of high resolution hydrogeophysics because of their different scales of measurement and the usually weak petrophysical relations among the measurements in this study we systematically explore the usefulness of a conditional stochastic simulation approach based on simulated annealing for this purpose first we generate a realistic model of an alluvial aquifer consisting of a 2d scale invariant porosity field on the basis of this model we generate synthetic neutron porosity logs and crosshole georadar tomographic surveys we then use the proposed geostatistical simulation approach to integrate this hydr

along shore variations of offshore flow 1 using eddy correlation data collected by the longez research aircraft the adjustment of atmospheric flow downstream from a coastline is examined along shore variation of the turbulence over the water is generated by the varying width of the upstream land strip between the sea and inland water over the coastal zone the turbulence is strongest downstream from the widest part of land the along shore variation of the turbulence decreases with increasing sea fetch due to horizontal mixing in other terms the footprint of the flux farther offshore includes a larger width of upstream land beyond 5 km sea fetch the along shore variation becomes small

structure and formation of the highly stable marine boundary layer over the gulf of maine 1 a shallow stable boundary layer is ubiquitous over the cool waters of the gulf of maine in summer this layer affects pollutant transport throughout the region by isolating overlying flow from the surface in this paper we explore how the stable boundary layer is formed and describe its characteristics the temperature profile of the lowest 1 2 km of the atmosphere over the gulf of maine is remarkably similar regardless of transport time over water or the time of day when the flow left the land provided only that the flow is offshore this similarity is forced by the roughly constant water temperature and the roughly constant temperature of the free troposphere over the continent however the processes leading to the similar profiles are quite different depending on the time of day when the flow crosses the coast air leaving the coast at night already has a stable profile whereas air leaving the coast at midday or afternoon has a deep mixed layer in the latter case the stable layer formation over the water is of interest using observations of surface fluxes profiles and winds on the noaa research vessel ronald h brown from the 2004 international consortium for atmospheric research in transport and transformation icartt new england air quality study we show that the formation of the stable layer which involves cooling a roughly 50 to 100 m deep layer by 5 15 k occurs within 10 km and a half hour after leaving the coast the internal boundary layer near shore is deeper than predicted by standard relationships historical data are explored and also show deeper internal boundary layers than predicted we also describe one exceptional case where a 200 m deep neutral layer was observed and discuss the degree of isolation of the stable boundary layer and its duration

structure of offshore flow abstract the horizontal and vertical structure of the mean flow and turbulent fluxes are examined using aircraft observations taken near a barrier island on the east coast of the united states during offshore flow periods the spatial structure is strongly influenced by the surface roughness and surface temperature discontinuities at the coast with offshore flow of warm air over cool water the sea surface momentum flux is large near the coast and decreases rapidly with increasing offshore distance or travel time the decrease is attributed to advection and decay of turbulence from land the rate of decrease is dependent on the characteristic timescale of the eddies in the upstream land based boundary layer that are advected over the ocean as a consequence the air sea momentum exchange near the coast is influenced by upstream conditions and similarity theory is not adequate to predict the flux the vertical structure reveals an elevated layer of downward momentum flux and turbulence energy maxima over

multivariate analysis of cross hole georadar velocity and attenuation tomograms for aquifer zonation 1 we have investigated the potential of combining cross hole georadar velocity and attenuation tomography as a method for characterizing heterogeneous alluvial aquifers a multivariate statistical technique known as k means cluster analysis is used to correlate and integrate information contained in velocity and attenuation tomograms cluster analysis allows us to identify objectively the major common trends in the tomographic data and thus to reduce the information to a limited number of characteristic parameter combinations the application of this procedure to two synthetic data sets indicates that it is a powerful tool for converting the complex relationships between the tomographically derived velocity and attenuation structures into a lithologically and hydrologically meaningful zonation of the probed region in addition these synthetic examples allow us to evaluate the reliability of further petrophysical parameter estimates we find that although absolute values of the tomographically inferred petrophysical parameters often differ significantly from the actual parameters the clustering approach enables us to reliably identify the major trends in the petrophysical properties finally we have applied the approach to a cross hole georadar data set collected in a well studied alluvial aquifer a comparison of the clustered tomographic section with well log data demonstrates that our approach delineates the hydrostratigraphic zonation

turbulence adjustment and scaling in an offshore convective internal boundary layer a casper case study abstractthe characteristics of a convective internal boundary layer cibl documented offshore during the east coast phase of the coupled air sea processes and electromagnetic ducting research cas

characterization of heterogeneous near surface materials by joint 2d inversion of dc resistivity and seismic data 1 we have developed a robust 2d joint inversion scheme incorporating the new concept of cross gradients of electrical resistivity and seismic velocity as constraints so as to investigate more precisely the resistivity velocity relationships in complex near surface environments the results of joint inversion of dc resistivity and seismic traveltime data from collocated experiments suggest that one can distinguish between different types or facies of unconsolidated and consolidated materials refining a previously proposed resistivity velocity interrelationship derived from separate inversions of the respective data sets a consistent interpretive structural model can be obtained from the joint inversion models

stochastic modeling of seafloor morphology inversion of sea beam data for second order statistics at scale lengths less than 100 km or so statistical descriptions of seafloor morphology can be usefully employed to characterize ridge crest processes off ridge tectonics and vulcanism sedimentation and postdepositional transport we seek to develop methods for the estimation of seafloor statistics that take into account the finite precision resolution and sampling obtained by actual echo sounding systems in this initial paper we restrict our attention to the problem of recovering second order statistics from data sets collected by multibeam devices such as sea beam the seafloor is modeled as a stationary zero mean gaussian random field completely specified by its two point covariance function we introduce an anisotropic two point covariance function that has five free parameters describing the amplitude orientation characteristic wave numbers and hausdorff fractal dimension of seafloor topography we formulate the general forward problem relating this model to the statistics of an ideal multibeam echo sounder in particular the along track autocovariance functions of individual beams and the cross covariance functions between beams of arbitrary separation using these second moments as data functionals we then pose the inverse problem of estimating the seafloor parameters from realistic noisy data sets with finite sampling and beamwidth and we solve this inverse problem by an iterative linearized least squares method the inversion method is applied to sea beam transit data from both the pacific and atlantic oceans sea beam system noise stands out as a sharp spike on the along track autocovariance function and can be modeled as a white noise process whose amplitude generally increases with beam angle the five parameters in our second order model can be estimated from the inversion of data sets comprising 100 200 km of track length in general the cross track wave number is the most poorly determined although uncertainties in the assumed sea beam response may bias the values of the fractal dimension using the assumed beamwidth the measured noise values and the seafloor parameters recovered from the inversion we generate sea beam synthetics whose statistical character can be directly compared with raw sea beam data for most of the track segments we have processed thus far the synthetics are similar to the data in the case of one atlantic profile however the comparison clearly indicates the necessity of incorporating higher order statistics the space domain procedures described in this paper can be extended for this purpose

a numerical modeling study of warm offshore flow over cool water abstract numerical simulations of boundary layer evolution in offshore flow of warm air over cool water are conducted and compared with aircraft observations of mean and turbulent fields made at duck north carolina two models are used a two dimensional high resolution mesoscale model with a turbulent kinetic energy closure scheme and a three dimensional large eddy simulation les model that explicitly resolves the largest turbulent scales both models simulate general aspects of the decoupling of the weakly convective boundary layer from the surface as it is advected offshore and the formation of an internal boundary layer over the cool water two sets of experiments are performed which indicate that complexities in upstream surface conditions play an important role in controlling the observed structure the first land sea experiments examine the transition from a rough surface having the same temperature as the ambient lower atmosphere to a smooth ocean surface that is 5 c cooler in the seco

coastal atmospheric circulation around an idealized cape during wind driven upwelling studied from a coupled ocean atmosphere model abstract the study analyzes atmospheric circulation around an idealized coastal cape during summertime upwelling favorable wind conditions simulated by a mesoscale coupled ocean atmosphere model the domain resembles an eastern ocean boundary with a single cape protruding into the ocean in the center of a coastline the model predicts the formation of an orographic wind intensification area on the lee side of the cape extending a few hundred kilometers downstream and seaward imposed initial conditions do not contain a low level temperature inversion which nevertheless forms on the lee side of the cape during the simulation and which is accompanied by high froude numbers diagnosed in that area suggesting the presence of the supercritical flow formation of such an inversion is likely caused by average easterly winds resulting on the lee side that bring warm air masses originating over land as well as by air warming during adiabatic descent on the lee side of the topographic obstacle mountain leeside

integration of diverse physical property models subsurface zonation and petrophysical parameter estimation based on fuzzy c means cluster analyses inversions of an individual geophysical data set can be highly nonunique and it is generally difficult to determine petrophysical parameters from geophysical data we show that both issues can be addressed by adopting a statistical multiparameter approach that requires the acquisition processing and separate inversion of two or more types of geophysical data to combine information contained in the physical property models that result from inverting the individual data sets and to estimate the spatial distribution of petrophysical parameters in regions where they are known at only a few locations we demonstrate the potential of the fuzzy c means fcm clustering technique after testing this new approach on synthetic data we apply it to limited crosshole georadar crosshole seismic gamma log and slug test data acquired within a shallow alluvial aquifer the derived multiparameter model effectively outlines the major sedimentary units observed in numerous boreholes and provides plausible estimates

refraction tomography over a buried waste disposal site determining the depth and geometry of a landfill s lower boundary is a difficult task potential field methods generally lack the necessary depth resolution and seismic reflection data are usually contaminated by source generated noise in the time range of interest 50 ms to address this problem we have developed a surface 2 d tomographic refraction scheme that is based on a fast finite difference eikonal solver and an inversion method that incorporates appropriate damping and smoothing constraints this new scheme has been applied to a first arrival traveltime data set collected across adjacent landfills in northern switzerland high quality seismic data were collected along five profiles that crossed the landfills and two that sampled undisturbed natural sediments seismic waves generated from multiple shots were recorded on large numbers of closely spaced receivers during quiet evening periods reliability of the resultant velocity tomograms was estimated on the basis of 1 ray diagrams 2 plot

early arrival waveform tomography on near surface refraction data we develop a waveform tomography method for estimating the velocity distribution that minimizes the waveform misfit between the predicted and observed early arrivals in space time seismograms by fitting the waveforms of early arrivals early arrival waveform tomographyewt naturally takes into account more general wave propagation effects compared to the high frequency method of traveltime tomography meaning that ewt can estimate a wider range of slowness wavenumbers another benefit of ewt is more reliable convergence compared to full waveform tomography because an early arrival misfit function contains fewer local minima synthetic test results verify that the waveform tomogram is much more accurate than the traveltime tomogram and that this algorithm has good convergence properties for marine data from the gulf of mexico the statics problem caused by shallow gassy muds was attacked by using ewt to obtain a more accurate velocity model using the waveform tomogram to correct for statics the stacked section was significantly improved compared to using the normal moveout nmo velocity and moderately improved compared to using the traveltime tomogram inverting high resolution land data from mapleton utah showed an ewt velocity tomogram that was more consistent with the ground truth trench log than the traveltime tomogram our results suggest that ewt can provide supplemental shorter wavelength information compared to the traveltime tomogram for both shallow and moderately deep seismic data

surface stress in offshore flow and quasi frictional decoupling aircraft data collected at approximately 15 m above the sea surface in the coastal zone are analyzed to examine the spatial distribution of surface stress advection of stronger turbulence from land dominates the near surface turbulence for the first few kilometers offshore with offshore flow of warm air over cold water strong stratification leads to very small surface stress because the stability restricts the momentum transfer to the waves the aerodynamic surface roughness decreases to very small values which in turn decreases atmospheric mixing the redevelopment of the boundary layer farther downstream is examined computation of fluxes from observations for stable cases is difficult due to a variety of errors including large random flux errors possible instrumental loss of small scale flux difference between the surface flux and that at the observational level and inadvertent capture of mesoscale motions in the computed turbulent fluctuations although the errors appear to be substantial the aircraft momentum fluxes compare favorably with those from sonic anemometers on two buoys and a tower at the end of a 570 m pier even with near collapse of the turbulence