changes in the salinity and porosity of sea ice samples during shipping and storage a theoreti cal examination of salinity and porosity changes introduced in sea ice samples by brine expulsion and gas entrapment caused by thermal cycling during shipping and storage shows that in extreme cases such effects can be significant resulting in 15 reductions in porosity 1 more representative scenarios give porosity changes of less than 2 which assuming that ice property variations scale with n 1 2 result in property variations of less than 1

meltwater circulation and permeability of arctic summer sea ice derived from hydrological field experiments abstractpermeability and meltwater flow have been studied in sea ice in the siberian and central arctic during the summers of 1995 and 1996 a bail test technique has been adapted to allow for measurements of in situ permeability found to range between 1011 and 108 m2 permeability varied by about a factor of 2 between 1995 above normal melt rates and 1996 below normal melt rates release of fluorescent tracers fluoresceine rhodamine furthermore allowed the derivation of flow velocities and assessment of the relevant driving forces hydraulic gradients in rough ice and wind stress in ponded ice were found to be particularly important driving meltwater over distances of several m day1 the mid to late summer ice was found permeable enough to completely divert meltwater from the surface into the ice interior it could be shown however that lower permeabilities of the upper ice layers as well as refreezing of meltwater are associated with significantly lower permeabilities in particular during the early melt season fostering development of surface melt ponds

in situ measurements of the evolution of young sea ice 1 we present data from in situ measurements of the salinity evolution of young sea ice in the arctic the measurements were carried out with very high vertical and temporal resolution over the course of a few days until the ice had reached a thickness of around 20 cm the measured bulk salinity profiles show that during ice growth sea ice salinity is continuous across the ice ocean interface and that there is no instantaneous loss of salt at the advancing front measured salt fluxes emanating from the ice are as high as 90 g m 2 h 1 during the first few hours of new ice formation and are roughly half as large during later stages of the experiments the bulk salinity within the ice decreases continuously with time from the ocean water salinity to a near steady state value of around 4 parts per thousand ppt these results are interpreted with ideas from mushy layer theory using a rayleigh number to analyze gravity drainage as the driving mechanism for the observed salt loss in our experiments gravity drainage occurs for a critical rayleigh number of around 10 in close agreement with earlier theoretical and experimental studies

thermomechanics of pack ice a thermodynamic formulation for pack ice is presented that includes a means of relating stresses in floes to thermally induced strain rates the formulation combines some basic thermodynamics as detailed in previous research the mechanics component includes viscous creep and mechanically induced strain rates due to typical floes being too large to bend or twist in response to spatially varying strain rates moreover the rheology quantifies the impact of existing cracks in the floe on the overall strain rate in the floe and the resulting stress state a paradigm is proposed which specifies tensile fracturing and the resulting stress relief as proportional to the amount of existing cracks in the floe and some measure of the tensile strength of the ice this allows the thermomechanical equations to be used for both first year and multiyear floes by differentiating the two by the extent of existing cracks the thermomechanical equations are applied in an inverse fashion to solve for flaw structure for a first year floe as well as a multiyear floe this is done by matching stresses predicted by the thermomechanical equations to observed stresses in the floes the results indicate that the top two thirds of the ice in the first year floe was relatively free of cracks while the bottom third of the floe had cracks covering 50 of the ice in the multiyear floe cracks covered 70 to 90 of the ice in the top two thirds of the floe while the bottom third of the floe had cracks covering 30 of the ice

equations for determining the gas and brine volumes in sea ice samples on a etabli des equations utilisables pour determiner le taux de gaz inclus dans la glace de mer a partir de mesures de densite de salinite et de temperature dans des gammes de temperatures entre 2 c et 30 c inversement ces relations peuvent etre utilisees pour calculer la densite de la glace de mer en fonction de la temperature et de la salinite en prenant en compte a la fois la presence de gaz et de cristaux de sel dans la glace on donne aussi des equations qui permettent le calcul du volume de gaz et d eau salee dans la glace a des temperatures autres que celle pour laquelle la densite a ete determinee

stochastic fracture simulation using pixel based multiple point geostatistics by integrating seismic radial anisotropy and well data applications in two hydrology sites we propose a pixel based multiple point simulation algorithm for stochastic simulation of near surface fractures using seismic radial anisotropy as secondary information the method borrows information from the training image of the fracture and anchoring within the secondary radial anisotropy data using wavelet based multiple point simulation framework the simulation was performed sequentially by sampling from the conditional cumulative density function ccdf of fracture conditioning to radial anisotropy for faster computation instead of calculating ccdf at each unknown location a limited number of ccdfs are calculated the patterns of the multiple point representation are extracted from the training image and are classified into multiple classes using the wavelet decomposition analysis each class is represented by a class prototype and ccdf during simulation the conditioning data are compared with the class prototypes and a random sample is generated from the ccdf of the best match class we validated the proposed simulation method using a synthetic fracture dataset a sensitivity analysis was also performed to show the impact of correlation between fracture and radial anisotropy and the resolution of the radial anisotropy results demonstrated that the reproduction of the fracture depends on its correlation with the radial anisotropy it was also observed that fracture reproduction is proportional to the resolution of the radial anisotropy we successfully applied our proposed model to two hydrogeological sites in which seismic radial anisotropy was obtained using the dispersion analysis of the surface wave

windows in arctic sea ice light transmission and ice algae in a refrozen lead the arctic ocean is rapidly changing from thicker multiyear to thinner first year ice cover with significant consequences for radiative transfer through the ice pack and light availability for algal growth a thinner more dynamic ice cover will possibly result in more frequent leads covered by newly formed ice with little snow cover we studied a refrozen lead 0 27 m ice in drifting pack ice north of svalbard 80 5 82 4 n in may june 2015 during the norwegian young sea ice expedition n ice2015 we measured downwelling incident and ice transmitted spectral irradiance and colored dissolved organic matter cdom particle absorption ultraviolet uv protecting mycosporine like amino acids maas and chlorophyll a chl a in melted sea ice samples we found occasionally very high maa concentrations up to 39 mg m 3 mean 4 5 7 8 mg m 3 and maa to chl a ratios up to 6 3 mean 1 2 1 3 disagreement in modelled and observed transmittance in the uv range let us conclude that maa signatures in cdom absorption spectra may be artefacts due to osmotic shock during ice melting although observed par transmittance through the thin ice was 5 40 times that of the adjacent thicker ice with deep snow cover ice algal standing stocks were low 2 31 mg chl a m 2 and similar to the adjacent ice ice algal accumulation in the lead was possibly delayed by the low inoculum and the time needed for photoacclimation to the high light environment however leads are important for phytoplankton growth by acting like windows into the water column

a 1 d enthalpy model of sea ice we present a 1 d enthalpy based model of sea ice that allows for quantitative studies of sea ice and its interaction with radiative processes melt ponds oceanic heat and salt fluxes internal density changes and surface heat fluxes on a single computational domain the model provides new insight into the interior structure and the salinity evolution of sea ice we compare our model results with measurements from laboratory experiments and show for example that no salt is lost from sea ice by brine expulsion

numerical simulations of the profile properties of undeformed first year sea ice during the growth season a simulation scheme is developed that estimates salinity profiles for first year sea ice during the growth season as a function of the growth history of the ice the model considers the dependence of the initial ice salinity on ice growth velocity and sea water salinity and also the subsequent drainage of brine from the ice the equation for ice growth assumes a linear temperature profile within the ice and is driven by surface heat balance equations that are based on smoothed climatic data for the central arctic basin the estimated salinity profiles are in good agreement with natural profiles although temperature and salinity profiles depend upon the time of the year when ice growth is initiated the brine volume profiles which they specify are essentially a unique function of ice thickness a conclusion that holds even when the insulative effects of snow are considered the temperature and brine volume profiles are then utilized to calculate the ice strength and elastic modulus profiles which in turn specify the composite mechanical properties of the ice sheets through the application of a theory developed by assur 1967 significant differences which are largest for thin ice sheets are observed between ice sheet properties as calculated using composite plate theory and properties calculated from uniform plate theory and average ice properties these results provide a justification for the practice common within the ice modeling community of parameterizing the mechanical behavior of pack ice on the basis of the ice thickness distribution

physical and biological controls on dms p dynamics in ice shelf influenced fast ice during a winter spring and a spring summer transitions we report the seasonal and vertical variations of dimethylsulfide dms and its precursor dimethylsulfoniopropionate dmsp in fast ice at cape evans mcmurdo sound antarctica during the spring summer transition in 2011 and winter spring transition in 2012 we compare the variations of dms p observed to the seasonal evolution of the ice algal biomass and of the physical properties of the ice cover with emphasis on the ice texture and brine dynamics isolated dms and dmsp maxima were found during both seasonal episodes in interior ice and corresponded to the occurrence of platelet crystals in the ice texture we show that platelet crystals formation corresponded in time and depth to the incorporation of dinoflagellates strong dmsp producers in the ice cover we also show that platelet crystals could modify the environmental stresses on algal cells and perturb the vertical redistribution of dms p concentrations we show that during the winter spring transition in 2012 the dms p profiles were strongly influenced by the development and decline of a diatom dominated bloom in the bottom ice with dmsp variations remarkably following chl a variations during the spring summer transition in 2011 the increase in brine volume fraction influencing ice permeability on warming was shown to trigger 1 an important release of dms to the under ice water through brine convection and 2 a vertical redistribution of dmsp across the ice

identifying discrete geologic structures that produce anomalous hydraulic response an inverse modeling approach 1 subsurface hydraulic response is controlled by discrete geologic structures in a variety of aquifer settings in this work we analyze data from the well studied alluvial fan system that underlies the lawrence livermore national laboratory there subsurface flow and transport behavior is strongly influenced by discrete channel deposits which are embedded within less permeable floodplain deposits we model the distribution of these deposits using a multiple point geostatistical approach that enables simulation of geologically plausible connected permeable bodies consistent with a training image by coupling the geostatistical model with a dynamic flow model in a simulation inversion framework we identify specific channel structures that are consistent with transient aquifer test data at six observation wells we perform shortest path analysis to characterize the geometry of the simulated channels and to locate critical high permeability conduits that control the system s response to pumping in one area all successful inverse solutions identify the same set of stacked channel deposits a geologic feature that provides an explanation for anomalous response behavior observed during the aquifer test

fracture characterization at valhall application of p wave amplitude variation with offset and azimuth avoa analysis to a 3d ocean bottom data set the delineation and characterization of fracturing is important in the successful exploitation of many hydrocarbon reservoirs such fracturing often occurs in preferentially aligned sets if the fractures are of subseismic scale this may result in seismic anisotropy thus measurements of anisotropy from seismic data may be used to delineate fracture patterns and investigate their properties here fracture induced anisotropy is investigated in the valhall field which lies in the norwegian sector of the north sea this field is a chalk reservoir with good porosity but variable permeability where fractures may significantly impact production e g during waterflooding to investigate the nature of fracturing in this reservoir p wave amplitude variation with offset and azimuth avoa is analyzed in a 3d ocean bottom cable obc data set in general 3d ocean bottom seismic obs acquisition leads to patchy coverage in offset and azimuth and this must be addressed when considering such data to overcome this challenge and others associated with 3d obs acquisition a new method for processing and analysis is presented for example a surface fitting approach which involves analyzing azimuthal variations in avo gradients is used to estimate the orientation and magnitude of the fracture induced anisotropy this approach is also more widely applicable to offset azimuth analysis of other attributes e g traveltimes and any data set where there has been true 3d data acquisition land or marine using this new methodology we derive high resolution maps of p wave anisotropy from the avoa analysis for the top chalk reflection at valhall these anisotropy maps show coherent but laterally varying trends synthetic avoa modeling using effective medium models indicates that if this anisotropy is from aligned fracturing the fractures are likely liquid filled with small aspect ratios and the fracture density must be high furthermore we show that the fracture normal direction is parallel to the direction of most positive avo gradient in other situations the reverse can be true i e the fracture normal direction can be parallel to the direction of the most negative avo gradient effective medium modeling or comparisons with anisotropy estimates from other approaches e g azimuthal variations in velocity must therefore be used to resolve this ambiguity the inferred fracture orientations and anisotropy magnitudes show a degree of correlation with the positions and alignments of larger scale faults which are estimated from 3d coherency analysis overall this work demonstrates that significant insight may be gained into the alignment and character of fracturing and the stress field variations throughout a field using this high resolution avoa method

a non destructive method for measuring the salinity and solid fraction of growing sea ice in situ we describe an instrument developed to make in situ measurements of salinity and solid fraction profiles in growing sea ice the vertical resolution of the measurements is up to a few millimeters with a temporal resolution of up to fractions of a second the technique is based on impedance measurements between platinum wires around which sea ice grows data obtained using this instrument in laboratory experiments are in good agreement with theoretical predictions in a field test in the arctic the bulk salinity of growing sea ice has been measured in situ throughout the whole depth of the ice layer the data are compared with bulk salinities obtained from ice cores and confirm the general understanding that the bulk salinity in ice core studies is significantly underestimated in the lower parts of the cores the approach can also be used in other glaciological applications and for general studies of two phase two component porous media

thermal expansion coefficients for sea ice coefficients of thermal linear expansion were determined for sea ice using a michelson interferometer over a temperature range of 4 to 15 c the coefficients varied from 45 10 6 to 54 10 6 c 1 for ice with a salinity of 2 ppt and from 33 10 6 to 53 10 6 c 1 for ice with a salinity of 4 ppt initially warming the sea ice resulted in coefficients that were the same as those for fresh water ice within the limits of experimental error subsequent sea ice cooling resulted in coefficients that were initially lower than those for fresh water ice but that asymptotically approached the coefficient values for fresh water ice at colder temperatures on the second warming and cooling cycle the coefficients of thermal linear expansion exhibited hysteresis and a decrease in magnitudes we have also shown that pettersson s 1883 and malmgren s 1927 measurements of the thermal volume expansion of sea ice were the result of phase transitions that caused brine expulsion when air free sea ice was cooled and internal porosity increases when sea ice was warmed our results indicate that petterson s 1883 and malmgren s 1927 measurements of the thermal volume expansion of sea ice are in error consequently theoretical descriptions based on their results are incorrect anderson 1960 zubov and savelyev given in doronin and kheisin 1977 doronin and kheisin 1977 our results for the initial sea ice warming cycle do agree with cox s 1983 analysis

multiple point statistical prediction on fracture networks at yucca mountain in many underground nuclear waste repository systems such as yucca mountain project water flow rate and amount of water seepage into the waste emplacement drifts are mainly determined by hydrological properties of fracture network in the surrounding rock mass natural fracture network system is not easy to describe especially with respect to its connectivity which is critically important for simulating the water flow field in this paper we introduced a new method for fracture network description and prediction termed multi point statistics mps the process of multi point statistical method is to record multiple point statistics concerning the connectivity patterns of fracture network from a known fracture map and to reproduce multiple scale training fracture patterns in a stochastic manner implicitly and directly it is applied to fracture data to study flow field behavior at yucca mountain waste repository system first mps method is used to create fracture network with original fracture training image from yucca mountain dataset after we adopt a harmonic and arithmetic average method to upscale the permeability to a coarse grid thm simulation is carried out to study near field water flow in surrounding rock of waste emplacement drifts our study shows that connectivity or pattern of fracture network can be grasped and reconstructed by multi point statistical method in theory it will lead to better prediction of fracture system characteristics and flow behavior meanwhile we can obtain variance from flow field which gives us a way to quantify uncertainty of models even in complicated coupled thm simulation it indicates that multi point statistics is a potential method to characterize and reconstruct natural fracture network in a fractured rock mass with advantages of quantifying connectivity of fracture system and its simulation uncertainty simultaneously

taking into account the complexity of natural fracture systems in reservoir single phase flow modelling abstract in order to develop a methodology for reservoir flow modelling that takes into account the complexity of natural fracture systems high quality fracture datasets were collected at different scales in a well exposed clastic formation at tayma saudi arabia and used to design a multiscale fracture model incorporating both large scale faults and medium to small scale fractures joints for numerical simulation flow modelling was then conducted taking into account three scales of permeability to represent the matrix joints and faults actually the most severe situation was considered where the permeability of the joints dominates strongly the one of the matrix the results obtained with this model show that on a local scale the maximum directional flow is always horizontal along the direction of a systematic joint set in this case nw se vertical flow is only possible where joints j and bedding planes b have conductivity ratios c j c b between 0 1 and 10 the flow properties of the model were then upscaled to simulate the entire reservoir through combining the flow properties of the jointed matrix represented by an equivalent permeability tensor with those of the large scale fault system which was modelled explicitly in a dual permeability system simulation of a pumping well to illustrate the hydraulic response of the multiscale fracture system according to different permeability ratios between the faults and the jointed rock matrix i e k f k m showed that the influence of the fault system begins to be visible at a permeability ratio of 100 at a ratio of 10 000 the hydraulic potential field is controlled completely by the fault system the fault planes becoming isopotential lines of the hydraulic field this multiscale fracture flow simulation procedure which combines the hydraulic effects of small to medium scale fractures and large scale faults could be very helpful in predicting flow responses in dual permeability reservoirs

sea ice salinity and structure a winter time series of salinity and its distribution 1 we present a winter time series of antarctic sea ice salinity from eastern mcmurdo sound an area close to an ice shelf where a subice platelet layer forms below the sea ice late in winter this dramatically changes the sea ice structure as the sea ice grows into the subice platelet layer every 2 weeks during the 5 months of sea ice formation salinity profiles were measured along with detailed measurements of ice structure and growth rates once the influence of growth rate on sea ice bulk salinity is removed the data from 69 cores and the results of a basic parameterization demonstrate that bulk salinity for platelet ice is higher than that for columnar sea ice we also present measurements of the salinity profile close to the ice water interface and use these to investigate the expected regime of fluid flow within the permeable portions of the sea ice with particular reference to mushy layer and percolation theory finally we provide a new distribution of sea ice salinity from 740 measurements which can be interpreted as the sum of two spatial fields that we attribute to sea ice samples with and without brine channels and which should be reproduced by any realistic sea ice models this distribution suggests that two measurements of quantities linearly linked to sea ice salinity must differ by 29 if they are to be considered different with 90 confidence

time lapse imaging of saline tracer transport in fractured rock using difference attenuation radar tomography 1 accurate characterization of fractured rock aquifer heterogeneity remains one of the most challenging and important problems in groundwater hydrology we demonstrate a promising strategy to identify preferential flow paths in fractured rock using a combination of geophysical monitoring and conventional hydrogeologic tests cross well differenceattenuation ground penetrating radar was used to monitor saline tracer migration in an experiment at the u s geological survey fractured rock hydrology research site in grafton county new hampshire radar data sets were collected every 10 min in three adjoining planes for 5 hours during each of 12 tracer tests an innovative inversion method accounts for data acquisition times and temporal changes in attenuation during data collection the inverse algorithm minimizes a combination of two functions the first is the sum of weighted squared data residuals second is a measure of solution complexity based on an a priori space time covariance function subject to constraints that limit radarattenuation changes to regions of the tomograms traversed by high difference attenuation ray paths the time series of tomograms indicate relative tracer concentrations and tracer arrival times in the image planes from these we infer the presence and location of a preferential flow path within a previously identified zone of transmissive fractures these results provide new insights into solute channeling and the nature of aquifer heterogeneity at the site index terms 0910 exploration geophysics data processing 0915 exploration geophysics downhole methods 1829 hydrology groundwater hydrology 1832 hydrology groundwater transport 1894 hydrology instruments and techniques keywords radar tomography fractured rock ground penetrating radar geophysics hydrogeophysics

desalination processes of sea ice revisited 1 we reexamine five processes that have been suggested to be important for the loss of salt from sea ice these processes are the initial fractionation of salt at the ice ocean interface brine diffusion brine expulsion gravity drainage and flushing with surface meltwater we present results from analytical and numerical studies as well as from laboratory and field experiments that show that among these processes only gravity drainage and flushing contribute to any measurable net loss of salt we show that during ice growth the salinity field is continuous across the ice ocean interface hence there is no immediate segregation of salt at the advancing front

polarimetric characteristics of sea ice in the sea of okhotsk observed by airborne l band sar the phased array l band sar palsar aboard the advanced land observing satellite alos is capable of globally acquiring fully polarimetric data in order to confirm the ability of l band polarimetric synthetic aperture radar sar to investigate sea ice before the alos launch we conducted a field experiment using an airborne polarimetric and interferometric sar pi sar in the sea of okhotsk in 1999 this paper presents the analyzed results of data acquired in that experiment the extracted polarimetric parameters of several ice types suggested that polarimetric coherences and phase differences between right right rr and left left ll are good candidates for discriminating ice types the polarimetric anisotropy as well as the beta angle of the first eigenvector calculated in the polarimetric decomposition procedure are alternative parameters that are sensitive to ice type differences due to the low depolarization characteristics of open water it could be discriminated from sea ice by scattering entropy in all incidence angle ranges from the relation between ice thickness and the polarimetric parameters we found that backscattering coefficients and vertical vv to horizontal hh backscattering ratio are highly correlated with ice thickness since the ratio is sensitive to ice surface dielectric constants a simple simulation using the integral equation method surface model was conducted by using the physical parameters of typical sea ice a two dimensional ice thickness map was derived from an empirical relation between the vv to hh backscattering ratio and ice thickness

textural characteristics and impurity content of meteoric and marine ice in the ronne ice shelf antarctica the texture and physical properties of an ice core recovered to 215 m depth from the ronne ice shelf antarctica have been studied with regard to formation and transformation of the ice at a depth of 152 8 m a sharp discontinuity marks the transition between meteoric ice accumulated from above and marine ice accreted from below as testified by electrolytical conductivity and stable isotope measurements as well as geophysical field surveys automated image analysis of thin sections indicates that the decrease in grain boundary density and the increase in grain cross sectional area with depth is commensurate with though not necessarily caused bythermodynamically driven grain growth down to 120m depth corresponding to a vertical strain of roughly 65 as computed with a simple temperature history particle path model the observed increase of grain boundary density i e a decrease of grain size with age in the marine ice is in part explained by the thermal history of this layer sediment inclusions at the top of the marine ice layer affect the observed grain boundary density profile by inhibiting grain growth and dynamic recrystallization this may allow some conclusions on the role of temperature particulate inclusions stress and strain rate in controlling the grain size evolution of deforming ice supplementing earlier laboratory experiments conducted at much shorter time scales salinities 0 026 parts per thousand brine volumes 0 09 0 2 parts per thousand and solid salt concentrations have been computed from electrolytical conductivity measurements mean of 51 0 x 10 6 s cm 1 for the marine ice an assessment of salt incorporation and desalination rates shows that these low salinities can at present only be explained by a unique densification mechanism of under water ice crystals at the base of the ice shelf

numerical experiments on permeability tensor and its application to jointed granite at stripa mine sweden rock masses containing a large number of geological discontinuities called joints are treated as homogeneous anisotropic porous media a permeability tensor hydraulically equivalent to a flow network formed by joints is formulated in terms of two tensors and a nondimensional scalar both depending only on the geometrical aspects of joints such as the spacing size orientation and aperture two dimensional numerical analyses on seepage flow through the networks support the validity of the present theory the information about the geometry of joints which is obtained from the ventilation drift at stripa mine sweden is interpreted to give the corresponding permeability tensor the permeability tensor is compared with the result of the large scale hydraulic conductivity test with the conclusion that it provides a reasonable prediction for the hydraulic properties of stripa jointed granite

under ice noise resulting from thermally induced fracturing of the arctic ice pack theory and a test case application a theory is presented that relates thermally induced fracturing of pack ice to under ice noise level variations it begins with the governing equations for the thermomechanics of pack ice the thermomechanics relates thermally induced strain rates to the stresses within various vertical layers of the floe in addition paradigms are developed which specify the relative quantity of fracturing and stress relief in the floe as the tensile yield strength of the ice is exceeded the thermomechanics is complemented by an acoustic propagation model that relates the number of fracture events at a given time to the acoustic levels at arbitrary frequency and depth below the ice the acoustic theory assumes that each fracture acts as a simple monopole source the fractures are evenly distributed horizontally and the energy of each fracture propagates through the ice and the water column on the basis of the governing equations for elastic waves in a horizontally stratified medium the results indicate that noise episodes resulting from fracturing occurring over the top 40 cm of a 160 cm thick floe will propagate over distances of up to 100 km however noise episodes associated with fracturing occurring in the lower 100 cm of the floe will only propagate over a range of 10 km the thermomechanics and acoustic propagation theories were used to develop a numerical model for predicting under ice noise levels for a given thermal forcing of floes within the arctic ice pack the model was used to simulate stresses in a multiyear floe and under ice noise levels at 500 hz at 305 m below the floe model predicted ice stresses and under ice noise levels compare quite well to observed stresses and noise variations during the fall of 1988 in the eastern arctic ocean the model predicts that most of the thermally induced under ice noise at 500 hz was a result of fracturing occurring between 5 and 30 cm below the ice surface for a 1 6 m thick multiyear floe

salinity profiles of antarctic sea ice field data and model results in order to describe and compare sea ice salinity distributions which are of interest in the study of physical and biological ice characteristics as well as ice ocean interaction we have computed composite profiles and fitted third degree polynomials to salinity data of 129 cores from the weddell sea four characteristic profile shapes have been recognized and described through the polynomial coefficients c s i and type profiles the field data have been compared with ideal salinity profiles generated by a simulation scheme based on thermodynamic growth under climatological conditions representative of the weddell sea composite salinity profiles agree well with simulations irrespective of the growth mechanism i e frazil or congelation suggesting that ice properties which depend on salinity or porosity may evolve independent of ice growth conditions analysis of salinity and 18o data in conjunction with the simulations demonstrates that apart from meteorological conditions controlling growth velocity and temperature distribution within the ice flooding and upward brine expulsion are important in raising top salinities as frequently observed low top salinities are typical of ice that has undergone retexturing and differential desalination salinity decreases towards the bottom of a floe are a result of high oceanic heat fluxes and snow cover effects as a consequence of these processes the bulk salinity of weddell sea ice cannot be described by a simple linear age thickness relationship as characteristic of arctic first year ice