experimental investigations on the thermal conductivity characteristics of beishan granitic rocks for china s hlw disposal abstract crystalline rocks are potential host rock types for the construction of high level radioactive waste hlw repositories a better understanding of thermal conductivity of rocks is essential to safe evaluation and engineering optimization of a hlw disposal system in the rock at depth in the present study experimental investigations on the thermal conductivity characteristics of 47 pairs of granitic rock specimens were conducted using the transient plane source tps method the specimens were collected from borehole cores in the beishan area which is being considered as the most potential candidate area for china s hlw repository to evaluate geological nature of the rocks mineralogical compositions of the rocks were identified and porosity of the specimens was measured the thermal conductivities of the specimens under dry and water saturated conditions were determined and the effect of water saturation on the thermal conductivity was investigated in addition the influence of temperature and axial compression stress on the thermal conductivity of dry specimens was studied the results revealed that the thermal conductivity of tested rocks was dependent on water saturation temperature and compression stress based on the obtained data some models considering porosity were established for describing the thermal conductivity characteristics of the tested rocks furthermore when the rocks have a similar porosity the quartz content dominates the thermal conductivity and there exists an obvious increase of the thermal conductivity with increasing quartz content the test results constitute the first systematic measurements on the beishan granitic rocks and can further be used for the development of thermal models for predicting thermal response near the underground excavations for hlw disposal

elevated arsenic in deeper groundwater of the western bengal basin india extent and controls from regional to local scale the deeper groundwater depending on definition of the bengal basin ganges brahmaputra delta has long been considered as an alternate safe drinking water source in areas with as enrichment in near surface groundwater the present study provides the first collective discussion on extent and controls of elevated as in deeper groundwater of a regional study area in the western part of the bengal basin deeper groundwater is defined here as non brackish potable cl 250 mg l groundwater available at the maximum accessed depth similar to 80 300 m the extent of elevated as in deeper groundwater in the study area seems to be largely controlled by the aquifer aquitard framework arsenic enriched deeper groundwater is mostly encountered north of 22 75 degrees n latitude where an unconfined to semi confined aquifer consisting of holocene to early neogene age gray sand dominates the hydrostratigraphy to 300 m depth below land surface aquifer sediments are not abnormally enriched in as at any depth but sediment and water chemistry are conducive to as mobilization in both shallow and deeper parts of the aquifer s the biogeochemical triggers are influenced by complex redox disequilibria results of numerical modeling and profiles of environmental tracers at a local scale study site suggest that deeper groundwater abstraction can draw as enriched water to 150 m depth within a few decades synchronous with the advent of wide scale irrigational pumping in west bengal india

climate control of decadal scale increases in apparent ages of eogenetic karst spring water abstract water quantity and quality in karst aquifers may depend on decadal scale variations in recharge or withdrawal which we hypothesize could be assessed through time series measurements of apparent ages of spring water we tested this hypothesis with analyses of various age tracers 3h 3he sf6 cfc 11 cfc 12 cfc 113 and selected solute concentrations dissolved oxygen do no3 mg and so4 from 6 springs in a single spring complex ichetucknee springs in northern florida over a 16 yr period these springs fall into two groups that reflect shallow short group 1 and deep long group 2 flow paths some tracer concentrations are altered with cfc 12 and cfc 113 concentrations yielding the most robust apparent ages these tracers show a 10 20 yr monotonic increase in apparent age from 1997 to 2013 including the flood recession that followed tropical storm debby in mid 2012 this increase in age indicates most water discharged during the study period recharged the aquifer within a few years of 1973 for group 2 springs and 1980 for group 1 springs inverse correlations between apparent age and do and no3 concentrations reflect reduced redox state in older water positive correlations between apparent age and mg and so4 concentrations reflect increased water rock reactions concentrated recharge in the decade around 1975 resulted from nearly 2 m of rain in excess of the monthly average that fell between 1960 and 2014 followed by a nearly 4 m deficit to 2014 this excess rain coincided with two major el nino events during the maximum cool phase in the atlantic multidecadal oscillation although regional water withdrawal increased nearly 5 fold between 1980 and 2005 withdrawals represent only 2 5 of ichetucknee river flow and are less important than decadal long variations in precipitation these results suggest that groundwater management should consider climate cycles as predictive tools for future water resources

assessing impact of irrigation water on groundwater recharge and quality in arid environment using cfcs tritium and stable isotopes in the zhangye basin northwest china summary environmental tracers cfcs 18o 2h and tritium were used to determine the natural groundwater recharge and the impact of irrigation activity on the groundwater system in the semi arid zhangye basin of china groundwaters in the irrigated areas have been identified as mixtures containing fractions recharged in different periods of time the cfc and 3h data show that the oldest fraction in the groundwater was recharged before 1950 whereas the younger fractions were recharged in different periods of time since 1950 stable isotope 18o 2h cfc and electrical conductivity data show that most of the samples can be regarded as binary mixtures with the river irrigation water presents the younger fraction and the regional groundwater presents the older fraction binary mixing model is used to estimate the age and fraction of the younger component most of the younger fraction was recharged after 1980s in response to the increasing irrigation activities compared to local precipitation surface water plays a major role in recharging the aquifer in the irrigated area the irrigation activity had more impact on the aquifer under thin unsaturated zone no 3 concentration in groundwater combined with a proper mixing model however they can provide evidences that the cfcs found in groundwater were introduced by infiltrating irrigation return flow and therefore reveal that human activities can produce a much localized water circulation and influence groundwater vulnerability

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

the thermal conductivity for granite with various water contents the thermal conductivities of granite were measured under different conditions of porosity and water content to investigate the effects of the porosity and water content on the thermal conductivity for the dry samples the thermal conductivities range from 2 12 w mk for the rocks with a high porosity to 3 12 w mk for the ones with a low porosity water sorbed samples have greater thermal conductivities than dry samples of the same granite the thermal conductivities range from 2 99 w mk for granites with a high porosity to 3 62 w mk for ones with a low porosity under saturated condition

role of the boundary layer moisture asymmetry in causing the eastward propagation of the madden julian oscillation the moisture budget associated with the eastward propagating madden julian oscillation mjo was diagnosed using 1979 2001 40 yr ecmwf re analysis era 40 data a marked zonal asymmetry of the moisture relative to the mjo convection appears in the planetary boundary layer pbl below 700 hpa creatingapotentiallymoreunstablestratificationtotheeastofthemjoconvectionandfavoringtheeastward propagation of mjo the pbl integrated moisture budget diagnosis indicates that the vertical advection of moisture dominates the low level moistening ahead of the convection a further diagnosis indicates that the leading term in the vertical moisture advection is the advection of the background moisture by the mjo ascending flow associated with pbl convergence the cause of the zonally asymmetric pbl convergence is further examined it is found that heating induced free atmospheric wave dynamics account for 75 90 of the total pbl convergence while the warm sst anomaly induced by air sea interaction contributes 10 25 of the total pbl convergence the horizontal moisture advection also plays a role in contributing to the pbl moistening ahead of the mjo convection the leadingterm in the moistureadvectionis the advectionacross the backgroundmoisture gradient by the mjo flow in the western indian ocean maritime continent and western pacific the meridional moisture advection by the mjo northerly flow dominates while in the eastern indian ocean the zonal moisture advection is greater the contribution of the moisture advection by synoptic eddies is in generalsmall ithas a negativeeffect overthetropicalindianoceanand westernpacificandbecomespositive in the maritime continent region

hydrological factors in the interpretation of stable isotopic proxy data present and past a european perspective in the context of this paper stable isotopic proxies are those preserving directly or via known or calculable fractionation factors a record of 18o 16o and or 2h 1h in the water which contributed to their growth suitable proxies include amongst others tree ring cellulose bone phosphate lake sediment minerals and speleothem fluid inclusions a principal aim of studying isotopic proxies is to gain more information about past climates through a knowledge of how rainfall isotope compositions have changed over time however converting back from proxy to rainfall is not necessarily straightforward because however well the isotopic fractionation due to proxy growth or formation is understood a variety of modifying processes may have intervened between this and the actual rainfall events three main reservoirs of environmental water may contribute to the isotopic compositions of terrestrial proxy indicators surface waters soil moisture and groundwater each of these can in principle be isotopically modified compared to rainfall in the locality this review examines these effects and how they may change under different european climate types at the present day it is concluded that while groundwater isotopic compositions typically represent closely the bulk composition of rainfall under a variety of climatic regimes soil and particularly lake waters require detailed study if their isotope systematics are to be adequately understood the review also finds that to a large extent the present is the key to the past in terms of recharge processes during the late pleistocene though glaciation may have had profound isotopic consequences in certain areas while a more general aridity led to the apparent absence of recharge in most areas for much of the late devensian

geochemistry of surface and ground water in guiyang china water rock interaction and pollution in a karst hydrological system the chemical compositions of the surface ground water of guiyang the capital city of guizhou province china are dominated by ca2 mg2 hco3 andso42 which have been derived largely from chemical weathering of carbonate rocks limestone and dolomite the production of so42 has multiple origins mainly from dissolution of sulfate evaporites oxidation of sulfide minerals and organic s in the strata and anthropogenic sources most ground water is exposed to soil co2 and therefore the h2co3 which attacks minerals contains much soil c in addition the h2so4 produced as a result of the oxidation of sulfides in s rich coal seams and or organic s is believed to be associated with the chemical weathering of rocks the major anthropogenic components in the surface and ground water include k na cl so42 andno3 with cl and no3 being the main contributors to ground water pollution in guiyang and its adjacent areas the seasonal variations in concentrations of anthropogenic components demonstrate that the karst ground water system is liable to pollution by human activities the higher content of no3 in ground water compared to surface water during the summer and winter seasons indicates that the karstic ground water system is not capable of denitrification and therefore does not easily recover once contaminated with nitrates

propagation mechanisms for the madden julian oscillation the madden julian oscillation mjo is examined using 20 years of outgoing long wave radiation and national centers for environmental prediction national center for atmospheric research re analysis data two mechanisms for the eastward propagation and regeneration of the convective anomalies are suggested the first is a local mechanism operating over the warm pool region at the phase of the mjo with a dipole structure to the convection anomalies there is enhanced tropical convection over the eastern indian ocean and reduced convection over the western pacific over the equatorial western indian ocean the equatorial rossby wave response to the west of the enhanced convection includes a region of anomalous surface divergence associated with the anomalous surface westerlies and pressure ridge this lends to suppress ascent in the boundary layer and shuts off the deep convection eventually leading to a convective anomaly of the opposite sign over the indonesian sector the equatorial kelvin wave response to the east of the enhanced convection includes a region of anomalous surface convergence into the anomalous equatorial surface easterlies and pressure trough which will tend to favour convection in this region the indonesian sector is also influenced by an equatorial rossby wave response of opposite sign to the west of die reduced convection over the western pacific which also has a region of anomalous surface convergence associated with its anomalous equatorial surface easterlies and pressure trough hence convective anomalies of either sign tend to erode themselves from the west and initiate a convective anomaly of opposite sign via their equatorial rossby wave response and expand to the east via their equatorial kelvin wave response the second mechanism is global involving an anomaly completing a circuit of the equator enhanced convection over the tropical western pacific excites a negative mean sea level pressure m s l p anomaly which radiates rapidly eastward as a dry equatorial kelvin wave at approximately 35 m s 1 over the eastern pacific it is blocked by the orographic barrier of the andes and central america for several days before propagating through the gap at panama after rapidly propagating as a dry equatorial kelvin wave over the atlantic the m s l p anomaly is delayed further by the east african highlands before it reaches the indian ocean and coincides with the development of enhanced convection at the start of the next mjo cycle

systematic decomposition of the madden julian oscillation into balanced and inertio gravity components we present a new method for the three dimensional multivariate decomposition of the mjo into balanced and inertio gravity ig components the method analyzes global fields with no filtering involved and it provides a quantitative comparison between the contribution of the rossby kelvin and other balanced and ig modes to the mjo circulation and its teleconnections results based on the era interim reanalysis data and the multivariate mjo index show that the rossby mode with the lowest meridional index is the largest contributor to the mjo circulation over the pacific a smaller role of the kelvin mode is diagnosed over the indian ocean and the maritime continent the mjo teleconnections in the polar stratosphere appear associated with the leading balanced vertical modes the presented method shows new ways of evaluating the mjo structure and its global impacts in weather and climate models

propagating and nonpropagating mjo events over maritime continent abstractthe observed outgoing longwave radiation olr and era interim data during 1979 2008 from november to april were analyzed to reveal fundamental differences between eastward propagating ep and nonpropagating np mjo events across the maritime continent mc it was found that when the maximum mjo convection arrives near 120 e a positive moisture tendency lies in a longitudinal zone 10 s 10 n 130 170 e for the ep cases whereas a negative tendency appears in the same region for the np cases in the latter cases there are clearly detectable westward propagating rossby wave type dry signals over the equatorial central western pacific the dry rossby wave signal may hinder the development of new convection to the east of the mjo convective center preventing the eastward propagation of the mjo a moisture budget analysis shows that the positive tendency of specific humidity in the ep composite is mainly attributed to the advection of the mean moisture by an intraseasonal ascending motion ano

dynamics oriented diagnostics for the madden julian oscillation abstractrealistic simulations of the madden julian oscillation mjo by global climate models gcms remain a great challenge to evaluate gcm simulations of the mjo the u s clivar mjo working group developed a standardized set of diagnostics providing a comprehensive assessment of statistical properties of the mjo here a suite of complementary diagnostics has been developed that provides discrimination and assessment of mjo simulations based on the perception that the mjo propagation has characteristic dynamic and thermodynamic structures the new dynamics oriented diagnostics help to evaluate whether a model produces eastward propagating mjos for the right reasons the diagnostics include 1 the horizontal structure of boundary layer moisture convergence blmc that moistens the lower troposphere to the east of a convection center 2 the preluding eastward propagation of blmc that leads the propagation of mjo precipitation by about 5 days 3 the horizontal structure of 850 hpa zonal wind and its

use of tritium and helium to define groundwater flow conditions in everglades national park the concentrations of tritium 3 h and helium isotopes 3 he and 4 he were used as tracers of groundwater flow in the surficial aquifer system sas beneath everglades national park enp south florida from ages determined by 3 h 3 he dating techniques groundwater within the upper 28 m originated within the last 30 years below 28 m waters originated prior to 30 years before present with evidence of mixing at the interface interannual variation of the 3 h 3 he ages within the upper 28 m was significant throughout the 3 year investigation corresponding with varying hydrologic conditions in the region of taylor slough bridge younger groundwater was consistently detected below older groundwater in the biscayne aquifer suggesting preferential flow to the lower part of the aquifer an increase in he with depth in the sas indicated that radiogenic 4 he produced in the underlying hawthorn group migrates into the sas by diffusion higher 4 he values in brackish groundwaters compared to fresh waters from similar depths suggested a possible enhanced vertical transport of 4 he in the seawater mixing zone groundwater salinity measurements indicated the presence of a wide 6 28 km seawater mixing zone comparison of groundwater levels with surface water levels in this zone indicated the potential for brackish groundwater discharge to the overlying everglades surface water

geochemical and statistical evidence of recharge mixing and controls on spring discharge in an eogenetic karst aquifer summary information about sources of recharge distributions of flow paths and the extent of water rock reactions in karst aquifers commonly result from monitoring spring chemistry and discharge to investigate the relationship between spring characteristics and the complexities of karst aquifers we couple variations in surface and groundwater chemistry to physical conditions including river stage precipitation and evapotranspiration et within a sink rise system through a 6 km portion of the upper floridan aquifer ufa in north central florida principal component analysis pca of time series major element compositions suggests that at least three sources of water affect spring discharge including allogenic recharge into a swallet diffuse recharge through a thin vadose zone and water upwelling from deep within the aquifer the deep water source exerts the strongest influence on water chemistry by providing a majority of na mg2 k cl and so 4 2 to the system anomalously high temperature at one of several monitoring wells reflects vertical flow of about 1 m year mass balance calculations suggest diffuse recharge and deep water upwelling can provide up to 50 of the spring discharge however their contributions depend on head gradients between the conduit and surrounding aquifer matrix which are influenced by variations in precipitation et and river stage our results indicate that upwelling from deep flow paths may provide significant contributions of water to spring discharge and that monitoring only springs limits interpretations of karst systems by masking critical components of the aquifer such as water sources and flow paths these results also suggest the matrix in eogenetic aquifers is a major pathway for flow even in a system dominated by conduits

a unified moisture mode framework for seasonality of the madden julian oscillation abstractthe madden julian oscillation mjo exhibits pronounced seasonality while it is largely characterized by equatorially eastward propagation during the boreal winter mjo convection undergoes marked poleward movement over the asian monsoon region during summer producing a significant modulation of monsoon rainfall in classical mjo theories that seek to interpret the distinct seasonality in mjo propagation features the role of equatorial wave dynamics has been emphasized for its eastward propagation whereas coupling between mjo convection and the mean monsoon flow is considered essential for its northward propagation in this study a unified physical framework based on the moisture mode theory is offered to explain the seasonality in mjo propagation moistening and drying caused by horizontal advection of the lower tropospheric mean moisture by mjo winds which was recently found to be critical for the eastward propagation of the winter mjo is also shown to play a dominant role in operating t

snow control on active layer thickness in steep alpine rock walls aiguille du midi 3842 m a s l mont blanc massif since the early 2000s a remarkable amount of rockfalls has been observed in permafrost areas of the mid latitude mountain ranges concurrently to hot summers this study explores the seasonal thaw st in permafrost rock walls of the aiguille du midi site 3842 m a s l mont blanc massif we first analyse six years of temperature records in three 10 m deep boreholes against air temperature at and a four year time series of pictures showing the snow conditions on two rock faces then we test the sensitivity of the active layer against eight snow fall scenarios using the 1 d surface energy balance and heat conduction model cryogrid 3 forced by in situ measurements from a vertical face snow falls occur all the year round at this elevation and play an important role for the active layer thickness alt but the snow cover and its control are highly heterogeneous a long lasting of a snow cover during spring early summer delays the st and reduces the alt the thicker and the more spatially continuous is the snow cover the stronger are the delay and alt reduction convective clouds could also reinforce this pattern the summer at and heat waves are the dominant controlling factors of the alt but summer snow falls can sometimes persist for several days on the rock surface and reduce the effect of the heat waves active layer can thicken during the early fall except if the snow starts to accumulate on the rock surface and favours the refreezing the timing of the snow fall is the most critical parameter to determine the snow effect on the alt this study suggests that the characteristics of the bedrock and snow accumulation steepness surface roughness and sun exposure must be taken into account to better understand the formation and changes of the active layer and its possible implications for rockfall triggering

flow of river water into a karstic limestone aquifer 2 dating the young fraction in groundwater mixtures in the upper floridan aquifer near valdosta georgia abstract tritium helium 3 3h 3he and chlorofluorocarbon cfcs cfc 11 cfc 12 cfc 113 data are used to date the young fraction in groundwater mixtures from a karstic limestone aquifer near valdosta georgia where regional paleowater in the upper floridan aquifer receives recharge from two young sources the flow of withlacoochee river water through sinkholes in the river bed and leakage of infiltration water through post eocene semi confining beds above the upper floridan aquifer in dating the young fraction of mixtures using cfcs it is necessary to reconstruct the cfc concentration that was in the young fraction prior to mixing the 3h 3he age is independent of the extent of dilution with older 3h free and 3hetrit free water the groundwater mixtures are designated as type 1 for mixtures of regional paleowater and regional infiltration water and type 2 for mixtures containing more than approximately 4 of river water the fractions of regional paleowater regional infiltration water and withlacoochee river water in the groundwater mixtures were determined from cl and 18o data for water from the upper floridan aquifer at valdosta georgia the chlorofluorocarbons cfc 11 and cfc 113 are removed by microbial degradation and or sorption processes in most anaerobic type 2 groundwater at valdosta but are present in some aerobic type 1 water cfc 12 persists in both so4 reducing and methanogenic water the very low detection limits for cfcs approximately 0 3 pg kg 1 permitted cfc 11 and cfc 12 dating of the fraction of regional infiltration water in type 1 mixtures and cfc 12 dating of the river water fraction in type 2 mixtures overall approximately 50 of the 85 water samples obtained from the upper floridan aquifer have cfc 12 based ages of the young fraction that are consistent with the 3h concentration of the groundwater because of uncertainties associated with very low 3h and 3he content in dilute mixtures 3h 3he dating is limited to the river water fraction in type 2 mixtures containing more than about 10 river water of the 41 water samples measured for 3h 3he dating dilution of 3h and low 3he concentration limited 3h 3he dating to 16 mixtures in which 3h 3he ages are defined with errors ranging from 2 to 7 5 a 1 after correction for dilution with assumed cfc free regional infiltration water and regional paleowater in the upper floridan aquifer adjusted cfc 12 ages agree with 3h 3he ages within 5 a or less in 7 of the 9 co dated type 2 mixtures tritium data and dating based on both cfc 11 and cfc 12 in type 1 mixtures indicate that travel times of infiltration water through the overlying post eocene semi confining beds exceed 35 a the cfc and 3h 3he dating indicate that the river fraction in most groundwater entered the groundwater reservoir in the past 20 to 30 a few domestic and municipal supply wells sampled intercept water younger than 5 a calculated velocities of river water in the upper floridan aquifer downgradient of the sinkhole area range from 0 4 to 8 2 m d radiocarbon data indicate that ages of the regional paleowater are on the 10 000 a time scale an average lag time of approximately 10 to 25 a is determined for discharge of groundwater from the surficial and intermediate aquifers above the upper floridan aquifer to the withlacoochee river

ice temperature and high geothermal flux at siple dome west antarctica from borehole measurements a verlical temperature profile through the west antarctic ice sheet wais at the summit of siple dome reveals an elevated geothermal flux this could be the root cause for the existence of a dynamic ice stream system in the wais siple dome is still frozen on its bed but adjacent ice streams have bed temperatures at the pressure melting point of ice although present day temperature increases due to climatic change do not have an immediate effect on the basal conditions that control the velocity of the ice indirect ellbcts like a rapid disintegration of the floating ice shelves or additional melt water input at the surface could give rise to speed up of the ice streams with an ensuing rise in sea level ongoing melt at the base of the ice and changes at the margins will allow continued rapid flow of the ice streams with a possibility of disintegration within a relatively short period of time of at least part of the wais

thermal and depositional history of early permian rio bonito formation of southern parana basin brazil abstract the parana basin is a large volcano sedimentary basin with a complex depositional history from ordovician to the cretaceous period during permian significant amounts of organic rich beds accumulated within the rio bonito and irati formations representing deposition in coastal deltaic and barrier lagoon and shallow marine environments respectively in this work the thermal history of these beds is examined from 16 vitrinite reflectance analyses of coal beds rio bonito formation integrated with previous data on coal rank and 21 apatite fission track aft analyses collected from 17 well profiles in the south of the parana basin coal samples showed three different maturity levels two with reflectances of 0 4 0 6 and 0 6 0 8 rr formed by the natural burial history of the basin the latter is restricted to the torres syncline area in contrast the third group reached much higher values 1 0 5 0 rr related to intrusive igneous rocks the aft data show thermal consistency with the reflectance values the sandstone samples related to the two lower reflectance patterns were partially reset preserving aft ages older than the stratigraphic age of the bed otherwise the samples severely affected by the magmatism have cretaceous and early cenozoic ages but some were much younger than the last magmatic event implying deep burial before cooling onset the mean track length distribution of the partially reset samples is short due to the inheritance of tracks preserved from basement cooling history however the population of fully reset samples gives crucial information on the maximum temperature reached and the age when cooling started at these conditions around 1 0 to 3 0 km of the parana basin sequences would have been removed from the surface of the studied areas by erosion since cretaceous regional variations in the amounts of removed sections were controlled by the structural framework mostly regional nw se and ne sw oriented structures

chemical evolution of groundwater near a sinkhole lake northern florida 1 flow patterns age of groundwater and influence of lake water leakage leakage from sinkhole lakes significantly influences recharge to the upper floridan aquifer in poorly confined sediments in northern florida environmental isotopes oxygen 18 deuterium and tritium chlorofluorocarbons cfcs cfc 11 ccl3f cfc 12 ccl2f2 and cfc 113 c2cl3f3 and solute tracers were used to investigate groundwater flow patterns near lake barco a seepage lake in a mantled karst setting in northern florida stable isotope data indicated that the groundwater downgradient from the lake contained 11 67 lake water leakage with a limit of detection of lake water in groundwater of 4 3 the mixing fractions of lake water leakage which passed through organic rich sediments in the lake bottom were directly proportional to the observed methane concentrations and increased with depth in the groundwater flow system in aerobic groundwater upgradient from lake barco cfc modeled recharge dates ranged from 1987 near the water table to the mid 1970s for water collected at a depth of 30 m below the water table cfc modeled recharge dates based on cfc 12 for anaerobic groundwater downgradient from the lake ranged from the late 1950s to the mid 1970s and were consistent with tritium data cfc modeled recharge dates based on cfc 11 indicated preferential microbial degradation in anoxic waters vertical hydraulic conductivities calculated using cfc 12 modeled recharge dates and darcy s law were 0 17 0 033 and 0 019 m d for the surficial aquifer intermediate confining unit and lake sediments respectively these conductivities agreed closely with those used in the calibration of a three dimensional groundwater flow model for transient and steady state flow conditions

groundwater residence time downgradient of trench no 22 at the chernobyl pilot site constraints on hydrogeological aquifer functioning following the explosion of reactor 4 at the chernobyl power plant in northern ukraine in 1986 contaminated soil and vegetation were buried in shallow trenches dug directly on site in an aeolian sand deposit these trenches are sources of radionuclide rn pollution the objective of the present study is to provide constraints for the chernobyl flow and rn transport models by characterising groundwater residence time a radiochronometer 3h 3he method t1 2 12 3 a and anthropogenic tracers including cfc and sf6 are investigated along with the water mass natural tracers na cl 18o and 2h the groundwater is stratified as evidenced by na and cl concentrations and stable isotopes 18o 2h in the upper aeolian layer the na cl relationship corresponds to evapotranspiration of precipitation while in the underlying alluvial layer an increase in na and cl with depth suggests both water rock interactions and mixing processes the 3h 3he and cfc apparent groundwater ages increase with depth ranging from recent 1 3 a at a 2 m depth below the groundwater table to much higher apparent ages of 50 60 a at 27 m depth below the groundwater table discrepancies in 3h 3he and cfc apparent ages 20 25 a and 3 10 a respectively were observed during the 2008 campaign at an intermediate depth immediately below the aeolian alluvial sand limit which were attributed to the complex water transfer processes extremely high sf6 concentrations well above equilibrium with the atmosphere and up to 1112 pptv are attributed to significant contamination of the soils following the nuclear reactor explosion in 1986 the sf6 concentration vs the apparent groundwater ages agrees with this interpretation as the high sf6 concentrations are all more recent than 1985 the persistence of the sf6 concentration suggests that sf6 was introduced in the soil atmosphere and slowly integrated in the groundwater moving along the hydraulic gradient the apparent age distribution in the lumped parameter models suggests an exponential or piston flow model in the upper geological section followed by more pronounced mixing processes in the lower section

age distribution estimation for karst groundwater issues of parameterization and complexity in inverse modeling by convolution summary convolution modeling is useful for investigating the temporal distribution of groundwater age based on environmental tracers the framework of a quasi transient convolution model that is applicable to twodomain flow in karst aquifers is presented the model was designed to provide an acceptable level of statistical confidence in parameter estimates when only chlorofluorocarbon cfc and tritium 3 h data are available we show how inverse modeling and uncertainty assessment can be used to constrain model parameterization to a level warranted by available data while allowing major aspects of the flow system to be examined as an example the model was applied to water from a pumped well open to the madison aquifer in central usa with input functions of cfc 11 cfc 12 cfc 113 and 3 h and was calibrated to several samples collected during a 16 year period a bimodal age distribution was modeled to represent quick and slow flow less than 50 years old the effects of pumping and hydraulic head on the relative volumetric fractions of these domains were found to be influential factors for transient flow quick flow and slow flow were estimated to be distributed mainly within the age ranges of 0 2 and 26 41 years respectively the fraction of long term flow 50 years was estimated but was not dateable the different tracers had different degrees of influence on parameter estimation and uncertainty assessments where

circulation factors determining the propagation speed of the madden julian oscillation abstractthe eastward propagating madden julian oscillation mjo events exhibit various speeds ranging from 1 to 9 m s 1 but what controls the propagation speed remains elusive this study attempt

deducing the distribution of terminal electron accepting processes in hydrologically diverse groundwater systems the distribution of microbially mediated terminal electron accepting processes teaps was investigated in four hydrologically diverse groundwater systems by considering patterns of electron acceptor nitrate sulfate consumption intermediate product hydrogen h sub 2 concentrations and final product ferrous ion sulfide and methane production in each hydrologic system a determination of predominant teaps could be arrived at but the level of confidence appropriate for each determination differed in a portion of the lacustrine aquifer of the san joaquin valley for example all three indicators sulfate concentrations decreasing h sub 2 concentrations in the 1 2 nmol range and sulfide concentrations increasing along flow paths identified sulfate reduction as the predominant teap leading to a high degree of confidence in the determination in portions of the floridan aquifer and a petroleum hydrocarbon contaminated aquifer sulfate reduction and methanogenesis are indicated by production of sulfide and methane and hydrogen concentrations in the 1 4 nmol and 5 14 nmol range respectively however because electron acceptor consumption could not be documented in these systems less confidence is warranted in the teap determination in the black creek aquifer no pattern of sulfate consumption and sulfide production were observed but h sub 2 concentrations indicated sulfate reduction as the predominant teap in this case more where just a single line of evidence is available the least confidence in the teap diagnosis is justified because this methodology is based on measurable water chemistry parameters and upon the physiology of microbial electron transfer processes it provides a better description of predominant redox processes in groundwater systems than more traditional eh based methods less

propagating versus nonpropagating madden julian oscillation events abstractbasinwide convective anomalies over the indian ocean io associated with the madden julian oscillation mjo sometimes propagate eastward and reach the west pacific wp but sometimes do not long term observations and reanalysis products are used to investigate the difference between the propagating and nonpropagating mjo events io convection onset events associated with the mjo are grouped into three categories based on the strengths of the simultaneous dry anomalies over the eastern maritime continent and wp the io convection anomaly preferentially makes eastward propagation and reaches the wp when the dry anomaly is stronger analysis of the column integrated moist static energy mse budget shows that horizontal advection moistens the atmosphere to the east of the positive mse anomaly associated with the active convection over the io and is of sufficient magnitude to explain the eastward propagation of the positive mse anomaly interpretation is complicated however by lack of closure in

circulation response to fast and slow mjo episodes abstractfast and slow madden julian oscillation mjo episodes have been identified from 850 and 200 hpa zonal wind and outgoing longwave radiation olr for 32 winters 16 october 17 march 1980 81 2011 12 for 26 fast cases the olr took no more than 10 days to propagate from phase 3 convection over the indian ocean to phase 6 convection over the western pacific for 8 slow cases the propagation took at least 20 days fast episode composite anomalies of 500 hpa height z500 show a developing rossby wave in the mid pacific with downstream propagation through mjo phases 2 4 changes in the frequency of occurrence of the nao weather regime are modest this rossby wave is forced by anomalous cooling over the maritime continent during phases 2 and 3 seen in phase independent wave activity flux the upper level anticyclonic response to phase 3 heating is a secondary source of wave activity the z500 slow episode composite response to mjo phases 1 and 2 is an enhanced aleutian low followed by a north a

the onset of convection in the madden julian oscillation abstract an observational study of the onset of convection in the madden julian oscillation mjo was performed composites of radiosonde data from the comprehensive aerological reference data set were constructed for an ensemble of tropical stations located in the indian ocean maritime continent and western pacific ocean the composites suggest that for the off equatorial stations used in this study the mjo period may be set by the buildup and discharge of the low level moist static energy this result supports the discharge recharge hypothesis of blade and hartmann mjo events appear to begin when the off equatorial atmosphere has been destabilized through a combination of low level moist static energy buildup and concurrent drying of the middle troposphere by subsidence in the wake of the previous cycle of mjo convection the low level moist static energy buildup is controlled by a corresponding increase in low level moisture the increase in low level moisture is not caused by the 1000 mb convergen

use of chemical and isotopic tracers to assess nitrate contamination and ground water age woodville karst plain usa concerns regarding ground water contamination in the woodville karst plain have arisen due to a steady increase in nitrate n concentrations 0 25 0 90 mg l during the past 30 years in wakulla springs a large regional discharge point for water 9 6 m3 s from the upper floridan aquifer ufa multiple isotopic and chemical tracers were used with geochemical and lumped parameter models exponential mixing em dispersion and combined exponential piston flow to assess 1 the sources and extent of nitrate contamination of ground water and springs and 2 mean transit times ages of ground water delta 15n no3 values 1 7 13 8 indicated that nitrate in ground water originated from localized sources of inorganic fertilizer and human animal wastes nitrate in spring waters 15n no3 5 3 8 9 originated from both inorganic and organic n sources nitrate n concentrations 1 0 mg l were associated with shallow wells open intervals less than 15 m below land surface elevated nitrate concentrations in deeper wells are consistent with mixtures of water from shallow and deep zones in the ufa as indicated from geochemical mixing models and the distribution of mean transit times 5 90 years estimated using lumped parameter flow models ground water with mean transit times of 10 years or less tended to have higher dissolved organic carbon concentrations lower dissolved solids and lower calcite saturation indices than older waters indicating mixing with nearby surface water that directly recharges the aquifer through sinkholes significantly higher values of ph magnesium dolomite saturation index and phosphate in springs and deep water 45 m relative to a shallow zone 45 m were associated with longer ground water transit times 50 90 years chemical differences with depth in the aquifer result from deep regional flow of water recharged through low permeability sediments clays and clayey sands of the hawthorn formation that overlie the ufa upgradient from the karst plain

groundwater flow system under a rapidly urbanizing coastal city as determined by hydrogeochemistry abstract in the jakarta area indonesia excessive groundwater pumping due to the rapidly increasing population has caused groundwater related problems such as brackish water contamination in coastal areas and land subsidence in this study we adopted multiple hydrogeochemical techniques to demonstrate the groundwater flow system in the jakarta area although almost all groundwater existing in the jakarta basin is recharged at similar elevations the water quality and residence time demonstrates a clear difference between the shallow and deep aquifers due to the rapid decrease in the groundwater potential in urban areas we found that the seawater intrusion and the shallow and deep groundwaters are mixing a conclusion confirmed by major ions br cl ratios and chlorofluorocarbon cfc 12 analysis spring water and groundwater samples collected from the southern mountainside area show younger age characteristics with high concentrations of 14 c and ca hco 3 type water chemistry we estimated the residence times of these groundwaters within 45 years under piston flow conditions by tritium analysis also these groundwater ages can be limited to 20 30 years with piston flow evaluated by cfcs moreover due to the magnitude of the cfc 12 concentration we can use a pseudo age indicator in this field study because we found a positive correlation between the major type of water chemistry and the cfc 12 concentration

mjo propagation shaped by zonal asymmetric structures results from 24 gcm simulations abstracteastward propagation is an essential characteristic of the madden julian oscillation mjo yet simulation of mjo propagation in general circulation models gcms remains a major challenge and understanding the causes of propagation remains controversial the present study explores why the gcms have diverse performances in mjo simulation by diagnosis of 24 gcm simulations an intrinsic linkage is found between mjo propagation and the zonal structural asymmetry with respect to the mjo convective center the observed and realistically simulated mjo eastward propagations are characterized by stronger kelvin easterly waves than rossby westerly waves in the lower troposphere which is opposite to the gill pattern where rossby westerly waves are 2 times stronger than kelvin easterly waves the gcms simulating stronger rossby westerly waves tend to show a stationary mjo mjo propagation performances are robustly correlated with the quality of simulated zonal asymmetries in the 850 hpa equatorial zonal w

determination of groundwater recharge regime and flowpath in the lower heihe river basin in an arid area of northwest china by using environmental tracers implications for vegetation degradation in the ejina oasis abstract environmental tracers cfcs stable isotopes 18o 2h and 3h and major ions were employed to study river infiltration and groundwater recharge in the aquifer system in the basin of the lower heihe river northwest china three groups of waters have been recognized 1 young groundwater connected to the river with large variation of cfc apparent ages ranging from 40 a and being depleted in 18o and 2h compared with the river water and 3 groundwater in gurinai a grassland located about 100 km from the river in which the predominant discharge is from the badain jaran desert with cfc apparent ages ranging from 25 to 50 a and being enriched in 18o and 2h compared to the river water the groundwater along the river contains cfcs and 3h down to depths of about 120 m and the shallow groundwater exhibits cfc apparent ages in a wide range which are not dependent on the well depth groundwaters along the river show a similar trend of enrichment in 18o and 2h as the river water whereas groundwaters in depression cones are depleted in heavier isotopes and have low cfc and 3h concentrations the cfc apparent age of the groundwater increases with increasing distance downstream indicating that the dominant part of the groundwater is from infiltration of river water in the upper reaches modifications of groundwater recharge are reflected in variations of stable isotope compositions as well as cfc and 3h concentrations in the groundwater that was recharged from the river over the last decades despite recharging from river water groundwater abstraction has induced a water balance deficit the riparian ecosystem in the ejina oasis is constrained by both decreased river flow and increased groundwater abstraction the vegetation degradation in the ejina oasis is controlled not only by natural aridification but also worsened by heavy groundwater abstraction and decreased river flow

thermal conductivity anisotropy of metasedimentary and igneous rocks 1 thermal conductivity anisotropy was determined for three sets of metasedimentary and igneous rocks from central utah usa most conductivity measurements were made in transient mode with a half space line source instrument oriented in two orthogonal directions on a flat face cut perpendicular to bedding one orientation of the probe yields thermal conductivity parallel to bedding kpar directly the other orientation of the probe measures a product of conductivities parallel and perpendicular to bedding from which the perpendicular conductivity kperp is calculated some direct measurements of kpar and kperp were made on oriented cylindrical discs using a conventional divided bar device in steady state mode anisotropy is defined as kpar kperp precambrian argillites from big cottonwood canyon have anisotropy values from 0 8 to 2 1 with corresponding conductivity perpendicular to bedding of 2 0 to 6 2 w m 1 k 1 anisotropy values for price canyon sedimentary samples are less than 1 2 with a mean of 1 04 although thermal conductivity perpendicular to bedding for the samples varied from 1 3 to 5 0 w m 1 k 1 the granitic rocks were found to be essentially isotropic with thermal conductivity perpendicular to bedding having a range of 2 2 to 3 2 w m 1 k 1 and a mean of 2 68 w m 1 k 1 the results confirm the observation by deming 1994 that anisotropy is negligible for rocks having kperp greater than 4 0 w m 1 k 1 and generally increases for low conductivity metamorphic and clay rich rocks there is little evidence however for his suggestion that thermal conductivity anisotropy of all rocks increases systematically to about 2 5 for low thermal conductivity rocks

geometry of a large scale low angle midcrustal thrust woodroffe thrust central australia the musgrave block in central australia exposes numerous large scale mylonitic shear zones developed during the intracontinental petermann orogeny around 560 520 ma the most prominent structure is the crustal scale over 600 km long e w trending woodroffe thrust which is broadly undulate but generally dips shallowly to moderately to the south and shows an approximately top to north sense of movement the estimated metamorphic conditions of mylonitization indicate a regional variation from predominantly midcrustal circa 520 620 c and 0 8 1 1 gpa to lower crustal 650 c and 1 0 1 3 gpa levels in the direction of thrusting which is also reflected in the distribution of preserved deformation microstructures this variation in metamorphic conditions is consistent with a south dipping thrust plane but is only small implying that a 60 km long n s segment of the woodroffe thrust was originally shallowly dipping at an average estimated angle of 6 the reconstructed geometry suggests that basement cored thick skinned midcrustal thrusts can be very shallowly dipping on a scale of many tens of kilometers in the direction of movement such a geometry would require the rocks along the thrust to be weak but field observations e g large volumes of syntectonic pseudotachylyte argue for a strong behavior at least transiently localization on a low angle near planar structure that crosscuts lithological layers requires a weak precursor such as a seismic rupture in the middle to lower crust if this was a single event the intracontinental earthquake must have been large with the rupture extending laterally over hundreds of kilometers

geochemical and isotopic evidence for palaeo seawater intrusion into the south coast aquifer of laizhou bay china this research aims to improve the current knowledge of groundwater salinisation processes in coastal aquifers using combined hydrochemical and isotopic parameters and inverse hydrochemical modelling field investigations were conducted in laizhou bay which is the area most seriously affected by seawater intrusion in north china during three sampling campaigns along a vertical transect in the changyiliutuan area 95 ground and surface water samples were collected for major ion and isotope analysis

tritium and helium isotopes as hydrologic tracers in a shallow unconfined aquifer measurements of tritium and 3he in groundwater can be used to calculate the age of tritium in groundwater such combined measurements on water samples thus provide a powerful tool towards understanding fluid flow in the near surface saturated zone we report tritium and helium isotope measurements on waters from an unconfined aquifer associated with a low level nuclear waste storage area these values are used to calculate ages of tritium in groundwater from 0 1 to 6 years from the groundwater ages and a three dimensional flow net hydraulic conductivities of 3 3 10 6 to 5 5 10 6 ms 1 for five wells and extreme values from a single well of 18 10 6 and 97 10 6ms 1 are calculated these values agree with hydraulic conductivities obtained from conventional aquifer tests the high conductivity value may indicate an area of preferred fluid flow

thermal conductivity of water saturated rocks from the ktb pilot hole at temperatures of 25 to 300 c the conductivitites of selected gneiss two and amphibolite one core samples have been measured under conditions of elevated temperature and pressure with a needle probe water saturated thermal conductivity measurements spanning temperatures from 25 to 300 c and hydrostatic pressures of 0 1 and 34 mpa confirm the general decrease in conductivity with increasing temperature but deviate significantly from results reported from measurements on dry samples over the same temperature range the thermal conductivity of water saturated amphibolite decreases with temperature at a rate approximately 40 less than the rate for dry amphibolite and the conductivity of water saturated gneiss decreases at a rate approximately 20 less than the rate for dry gneiss the available evidence points to thermal cracking as the primary cause of the more rapid decrease in dry thermal conductivity with temperature the effects of thermal cracking were also observed in the water saturated samples but resulted in a net decrease in room temperature conductivity of less than 3 these results highlight the importance of duplicating in situ conditions when determining thermal conductivity for the deep crust

effects of enhanced front walker cell on the eastward propagation of the mjo abstractwell organized eastward propagation of the madden julian oscillation mjo is found to be accompanied by the leading suppressed convection lsc over the maritime continent mc and the wes

barrier effect of the indo pacific maritime continent on the mjo perspectives from tracking mjo precipitation abstractexplanations for the barrier effect of the indo pacific maritime continent mc on the mjo should satisfy two criteria first they should include specific features of the mc namely its intricate land sea distributions and elevated terrains second they should include mechanisms for both the barrier effect and its overcoming by some mjo events guided by these two criteria a precipitation tracking method is applied to identify mjo events that propagate across the mc mjo c and those that are blocked by the mc mjo b about a half of mjo events that form over the indian ocean propagate through the mc most of them 75 become weakened over the mc the barrier effect cannot be explained in terms of the strength horizontal scale or spatial distribution of mjo convection when it approaches the mc from the west a distinction between mjo b and mjo c is their precipitation over the sea versus land in the mc region mjo c events rain much more over the sea than over land whereas rainfall over

thermophysical properties of coal measure strata under high temperature thermophysical properties such as specific heat capacity thermal conductivity and thermal diffusivity of coal measure strata at a wide range of temperatures are important to coal in situ gasification with environmental treatments these thermophysical properties have been investigated for different rocks but few are available for the rocks from coal measure strata this study experimentally investigated the specific heat capacity and the thermal conductivity of six types of rock samples from coal measure strata including sandy mudstone 1 and 2 mudstone siltstone coarse sandstone and fine sandstone when the testing temperature varies from 100 to 1000 c two critical temperatures 500 c for sandy mudstone 1 and 400 c for the other five types of rock samples were observed the test results show that both the specific heat capacity and the thermal conductivity decrease with the increase of temperature when the testing temperature is below the critical temperature when the testing temperature is over the critical temperature the specific heat capacity is almost constant and the thermal conductivity still continues decreasing these test results further show that the classical physics theory can well predict the experimental data for both specific heat capacity and thermal conductivity of six rocks

use of isotopic tracers to characterize the interaction of water components and nitrate contamination in the arid rasafeh area syria chemical and isotopic data in atmospheric precipitation surface water and groundwater in arid rasafeh area northeast syria are used to clarify the status of groundwater quality the interaction of water components groundwater dating and vulnerability to anthropogenic contamination interpretation of chemical data with thermodynamic calculation reveals that the dissolution of evaporate mineral is the main factor of high salinity the 18o and 2h relationships indicate that the groundwater is fed by mixing water from euphrates river and precipitation and the isotope balance equation were used to estimate the contribution of the euphrates river to the aquifers recharge high tritium content together with high 14c activity in the majority of groundwater samples indicate shorter residence times and consequently potentially greater recharge the presence of high nitrate concentration associated with high tritium concentration in both shallow and deep aquifer units indicates the presence of high permeability so that groundwater is highly susceptible to anthropogenic contamination nitrate seems to derive exclusively from the application of n fertilizers the high nitrate values are characteristic of the areas with intensive agricultural activity indicating the importance of irrigated return flow on the groundwater

mineralogy porosity and fluid control on thermal conductivity of sedimentary rocks summary estimates of thermal conductivity of the main non clay and clay sedimentary minerals are presented especially for the case of argillaceous ones these estimates are averaged estimates based on the interpretation of laboratory conductivity porosity and mineralogy measurements performed on small volumes of the order of 100cm3 of water saturated moist and air saturated samples the sampling is representative of the main sedimentary rocks sandstones carbonates evaporites and shales and it is composed of samples considered as structurally isotropic material first we experimentally verify the first order control of mineralogy porosity and fluid content on bulk conductivity and we demonstrate that such influences may be predicted accurately using a geometric mean model as long as isotropic samples are used then we interpret the data using an inverse method in order to estimate the average mineral conductivities of the main non clay and clay minerals which give the best fit to the individual laboratory measurements through the geometric mean model the analysis is based on measurements on 82 non clay samples and 29 clay samples taken on oil well cores or cuttings on outcrops and on artificially recompacted samples estimates of average mineral conductivities returned by the inversion process for the main non clay minerals are similar to generally admitted values 7 7 w m k for quartz 3 3 w m i k for calcite 5 3 w m l k for dolomite and 6 3 w m k for anhydrite values obtained for the clay minerals are systematically lower than those obtained for non clay ones they are of the order of 1 9 w m k for illite and smectite 2 6 w m k for kaolinite and 3 3 w m l k for chlorite these estimates combined with porosity and mineralogy data are used with the geometric mean model in order to verify its first order validity for predicting thermal conductivity of small volumes of porous isotropic sedimentary rocks the bulk conductivity is predicted with an accuracy of the order of f10 per cent for moist or water saturated samples and of the order of f20 per cent for air saturated samples

effect of water saturation and temperature in the range of 193 to 373 k on the thermal conductivity of sandstone abstract the thermal conductivity of porous media is crucial for many geological and engineering projects although the thermal conductivity at low temperatures is often overlooked it is of great significance to calculate the amount of heat that the ice sheet absorbs from the earth in this study the thermal conductivity of dry and water saturated sandstone was measured in the temperature range of 193 to 373 k using a transient hot wire method all samples were collected from east china with a sample porosity distribution of 5 to 13 the effects of temperature water saturation and phase transition of fluid in the pores were investigated the results indicate that the thermal conductivity decreases with an increase in temperature and that the decrease is steeper when the temperature is below 273 k moreover it is found that the thermal conductivity of the saturated sandstone is larger than that of the dry sandstone with an increase in porosity the thermal conductivity significantly increases in saturated sandstone but remains almost the same or even decreases in dry sandstones finally it is revealed that the effect of phase transformation on the thermal conductivity is significant when the water in pores becomes ice the thermal conductivity increases significantly and increases further as the temperature decreases

frictional moisture convergence in a composite life cycle of the madden julian oscillation abstract a composite life cycle of the madden julian oscillation mjo is constructed using an index based on the first two eofs of the bandpass filtered 20 80 days 850 mb zonal wind averaged from 5 n to 5 s every 2 5 around the equator precipitation 1000 mb convergence 850 mb wind and 200 mb wind are composited for the period 1979 95 water vapor integrated from the surface to 300 mb is composited for the period 1988 92 frictional moisture convergence at the equator is shown to play an important role in the life cycle of the madden julian oscillation mjo regions of boundary layer convergence foster growth of positive water vapor anomalies to the east of convection this convergence coincides with 850 mb easterly wind anomalies as is consistent with kelvin wave dynamics drying of the atmosphere occurs rapidly after the passage of convection with the onset of 850 mb westerly perturbations possible mechanisms for this drying include boundary layer divergence and subsidence or horizontal advect

transport and degradation of chlorofluorocarbons cfcs in the pyritic rabis creek aquifer denmark 1 vertical profiles of the chlorofluorocarbons cfc 11 cfc 12 and cfc 113 penetrating aerobic and anaerobic parts of a shallow sandy aquifer show that the cfc gases are degraded in the 1 m thick transition zone from aerobic to anaerobic groundwater in a pyritic sand aquifer at rabis creek denmark two dimensional solute transport simulations with either zero order or first order degradation in the anaerobic zone corroborate this interpretation the transport model was previously calibrated against detailed tritium profiles in the same wells first order degradation is found to best match the observed cfc profiles yielding an approximate half life of a few months for cfc 11 degradation is not as clearly recognized for cfc 12 and cfc 113 but it may occur with rates corresponding to a half life of a few years or more data indicate a geochemical control of the cfc concentration gradient at the redox front and that denitrification and denitrifiers are not of major importance for the observed cfc degradation the responsible mechanism behind the observed degradation is not known but we suggest that reductive dehalogenation by surface bound fe ii on pyrite possibly enhanced by the presence of fe iii bearing weathering products green rust may be a plausible mechanism the observed data and the performed simulations confirm the potential application of the cfc gases as age dating tools in the aerobic part of the investigated aquifer but also that cfc data must be analyzed carefully before it is used as a dating tool in reducing aquifers because degradation may have occurred the use of multiple or alternative tracers should be considered in anaerobic environments

a mass flux scheme view of a high resolution simulation of a transition from shallow to deep cumulus convection in this paper an idealized high resolution simulation of a gradually forced transition from shallow nonprecipitating to deep precipitating cumulus convection is described how the cloud and transport statistics evolve as the convection deepens is explored and the collected statistics are used to evaluate assumptions in current cumulus schemes the statistical analysis methodologies that are used do not require tracing the history of individual clouds or air parcels instead they rely on probing the ensemble characteristics of cumulus convection in the large model dataset they appear to be an attractive way for analyzing outputs from cloud resolving numerical experiments throughout the simulation it is found that 1 the initial thermodynamic properties of the updrafts at the cloud base have rather tight distributions 2 contrary to the assumption made in many cumulus schemes nearly undiluted air parcels are too infrequent to be relevant to any stage of the simulated convection and 3 a simple model with a spectrum of entraining plumes appears to reproduce most features of the cloudy updrafts but significantly overpredicts the mass flux as the updrafts approach their levels of zero buoyancy a buoyancy sorting model was suggested as a potential remedy the organized circulations of cold pools seem to create clouds with larger sized bases and may correspondingly contribute to their smaller lateral entrainment rates our results do not support a mass flux closure based solely on convective available potential energy cape and are in general agreement with a convective inhibition cin based closure the general similarity in the ensemble characteristics of shallow and deep convection and the continuous evolution of the thermodynamic structure during the transition provide justification for developing a single unified cumulus parameterization that encompasses both shallow and deep convection

key processes for the eastward propagation of the madden julian oscillation based on multimodel simulations as a prominent climate variability mode with widespread influences on global weather extremes the madden julian oscillation mjo remains poorly represented in the latest generation of general circulation models gcms with a particular challenge in simulating its eastward propagating convective signals in this study by analyzing multi model simulations from a recent global mjo model evaluation project an effort is made to identify key processes for the eastward propagation of the mjo through analyses of moisture entropy me processes under a moisture mode framework for the mjo the column integrated horizontal me advection is found to play a critical role for the eastward propagation of the mjo in both observations and good mjo models with a primary contribution through advection of the lower tropospheric seasonal mean me by the mjo anomalous circulations by contrast the horizontal me advection effect for the eastward propagation is greatly underestimated in poor mjo gcms due to model deficiencies in simulating both the seasonal mean me pattern and mjo circulations leading to a largely stationary mjo mode in these gcms these results thus pinpoint an important guidance towards improved representation of the mjo in climate and weather forecast models while this study mainly focuses on fundamental physics for the mjo propagation over the indian ocean complex influences by the maritime continent on the mjo and also me processes associated with the mjo over the western pacific warrant further investigations

initial thermal conditions around an underground research tunnel at shallow depth the initial thermal conditions around a shallow research tunnel in korea were investigated based on the data analysis of rock properties in situ observation and a computer simulation the measured thermal conductivity data were used for evaluating different theoretical estimations based on mineral composition porosity and saturation with a consideration of total porosity which was assumed to be twice of effective porosity the prediction with geometric mean could be improved in the case of three phase system consisted of minerals water and air however geometric mean overestimated especially in low saturation condition by using the chaudhary and bhandari equation for three phase system we could predict the measured thermal conductivity with about 10 error in low saturation condition with the data of porosity variation and saturation expected at kurt it was possible to predict the thermal conductivity increases with depth and stabilized at 3 2 w mk below 50 m considering the surface topography around kurt sequential tunnel excavation depth dependent rock properties and seasonal temperature variation of the air the time and depth dependent thermal conditions around kurt were predicted by a three dimensional computer simulation using flac3d

recharge sources and hydrochemical evolution of an urban karst aquifer sete lagoas mg brazil the current water supply for the city of sete lagoas brazil is almost entirely groundwater from the sete lagoas karst aquifer with a small contribution from a fractured basement rock aquifer characterizing the hydrogeologic processes is important for proper water resource management avoiding contamination and other future issues the main goal of this study is to identify active hydrogeological processes such as possible surface ground water interactions sources of recharge and the hydrochemical evolution of groundwater through the use of stable isotopes 18o and 2h and major ion data the groundwater samples were collected from the karst aquifer central urban area and from the fractured aquifer southern part of the city surface water samples were collected from the seven main lakes and rainwater was sampled over a period of one year the stable isotope results indicated the groundwater origin is directly from local precipitation having a limited recharge period and locally receiving surface water contributions groundwater quality in the central urban area may be influenced by surface water infiltration where the karst aquifer is in contact with overlying unconsolidated sediments some samples with nitrate concentration of 10 mg l or higher indicates the natural composition of the groundwater has been altered by urban sewage contamination the highest concentrations of major ions were found in the central region where the most karstified area from the sete lagoas formation is located these data suggest a longer residence time for this water indicating more mineralization in accordance with the geological information

a model for the boreal summer intraseasonal oscillation abstract the tropical intraseasonal oscillation iso exhibits pronounced seasonality the boreal summer iso is more complex than its winter counterpart due to the coexistence of equatorial eastward off equatorial westward and northward propagating low frequency modes and their interactions based on observational evidence and results obtained from numerical experiments a mechanism is proposed for the boreal summer iso in which the northern hemisphere summer monsoon nhsm circulation and moist static energy distribution play essential roles with a climatological july mean basic state the life cycle of model low frequency waves consists of four processes an equatorial eastward propagation of a coupled kelvin rossby wave packet an emanation of moist rossby waves in the western pacific a westward propagation and amplification of the rossby waves in south asian monsoon regions and a reinitiation of the equatorial disturbances over the central indian ocean the life cycle spans about one month and p

isotope signatures and hydrochemistry as tools in assessing groundwater occurrence and dynamics in a coastal arid aquifer groundwater from the la paz arid coastal aquifer in baja california mexico is essentially the only source of drinking water for the local population and tourists as well as irrigation water for agricultural needs the intensive exploitation of the aquifer and water cycling has resulted in groundwater abatement up to 10 m and high salinity up to 5800 mg l 1 a study using hydrochemistry isotopic deuterium oxygen 18 and carbon 14 and gaseous tracers chlorofluorocarbons cfc 11 cfc 12 cfc 113 as well as multivariate statistics was developed to elucidate groundwater composition flow and occurrence groundwater is of meteoric origin and a large proportion is subject to evaporation the primary natural recharge is generated in the el novillo and las cruces ranges and groundwater subsequently flows in a se nw direction toward the coast the initial water type is the result of discordant dissolution of silicate minerals and ion exchange on soils in the lower plain portion the aquifer system is recharged from irrigation return flow and seawater intrusion which significantly affects groundwater chemistry nitrate and chloride concentrations indicate that groundwater is highly affected by an overuse of fertilizers in agricultural activities but there is little effect from urban activities seawater intrusion has progressed rapidly during the past decade and the impact currently extends 13 km inland radiocarbon residence time calculations suggest that groundwater is modern with the exception of chametla and el centerario sites in the central and western lowlands with ages of up to 5000 years these waters indicate an additional recharge source for the upconing of fossil groundwater or regional flow

estimation of the thermal conductivity anisotropy of rock with application to the determination of terrestrial heat flow a moderately large data set of mostly sedimentary and metamorphic rocks compiled from the literature shows an inverse correlation between thermal conductivity anisotropy and thermal conductivity perpendicular to bedding the empirical relationship can be represented by a simple two component end member mixing model one end member is anisotropic x z 2 5 and has a relatively low thermal conductivity perpendicular to bedding z 1 w m k the other end member is isotropic and has a relatively high thermal conductivity perpendicular to bedding 4 w m k the proposed model may be used to derive a correction for anisotropic effects observed during thermal conductivity measurements on mixtures of randomly oriented aggregates although the accuracy and reliability of a universal correction procedure remain to be determined the proposed correction scheme should enhance our ability to estimate accurately heat flow in sedimentary basins where generally only borehole cuttings are available for thermal conductivity measurements

thermal conductivity characterisation of shallow ground via correlations with geophysical parameters abstract thermal conductivity is an important physical property of geological formations for example a comprehensive assessment of the thermal conductivity variations in the shallow ground surrounding a heat exchanger borehole can be used to determine the installation parameters of a ground source heat pump however in some locations it is not possible to measure thermal conductivity directly one of the most common methods to indirectly infer thermal conductivity is to establish correlations between thermal conductivity and various geophysical parameters by utilising test data acquired from drilling sites and ascertaining the corresponding geophysical parameters via non invasive geophysical methods such correlations can be obtained at 11 test sites the thermal conductivities were measured in situ via thermal response testing and the corresponding values for the s wave velocity and density were calculated using the microtremor survey method msm the correlations between the thermal conductivity s wave velocity and density in the tested shallow ground were built by exponential fitting by utilising the established correlations two dimensional 2d cross sections along the microtremor survey line were created to illustrate the thermal conductivity variations in the shallow ground these results demonstrate that this approach can be used to infer the thermal conductivities of areas that cannot be tested directly

using hydrochemical stable isotope and river water recharge data to identify groundwater flow paths in a deeply buried karst system the deeply buried river connected xishan karst aquifer xka in western beijing china has been suffering from diminishing recharge for several decades which in turn leads to the disappearing of spring water outflows and continuously lowering of groundwater level in the area thus it is important to correctly recognize the groundwater recharge and flow paths for the sustainable development of the xka to investigate these issues the hydrochemical and isotopic compositions are analysed for both surface water and groundwater samples collected over an area of about 280 km2 results show that a the river water is characterized by high na contents b the 2h and 18o values in the river water are distinctively higher than those of groundwater samples after experiencing the long time evaporative enrichment in the upstream reservoir c the sr concentrations and 87sr 86sr ratios of groundwater clearly indicated the interaction between water and carbonate minerals but excluded the water silicate interaction and d the groundwater samples in the direct recharge area of the xka have the lowest na concentrations and the 2h and 18o values based on the large differences in the na contents and 18o values of groundwater and surface water a simple two component mixing model is developed for the study area and the fractions of the river water are estimated for groundwater samples we find that the distribution pattern of the river water fractions in the xka clearly shows a change of directions in the preferential flow path of the groundwater from its source zone to the discharge area overall our results suggest that the recharged surface water can be a useful evidence for delineating the groundwater flow path in river connected karst aquifer this study improves our understanding of the heterogeneity in karst groundwater systems