estimating thermal inflow to el chichon crater lake using the energy budget chemical and isotope balance approaches abstract el chichon crater lake appeared immediately after the 1982 catastrophic eruption in a newly formed 1 km wide explosive crater during the first 2 years after the eruption the lake transformed from hot and ultra acidic caused by dissolution of magmatic gases to a warm and less acidic lake due to a rapid magmatic to hydrothermal transition input of hydrothermal fluids and oxidation of h 2 s to sulfate chemical composition of the lake water and other thermal fluids discharging in the crater stable isotope composition d and 18 o of lake water gas condensates and thermal waters collected in 1995 2006 were used for the mass balance calculations cl so 4 and isotopic composition of the thermal flux from the crater floor the calculated fluxes of thermal fluid by different mass balance approaches become of the same order of magnitude as those derived from the energy budget model if values of 1 9 and 2 mmol mol are taken for the catchment coefficient and the average h 2 s concentration in the hydrothermal vapors respectively the total heat power from the crater is estimated to be between 35 and 60 mw and the co 2 flux is not higher than 150 t day or 200 gm 2 day 1

estimating groundwater exchange with lakes 1 the stable isotope mass balance method groundwater inflow and outflow contributions to the hydrologic budget of lakes can be determined using a stable isotope 18o 16o mass balance method the stable isotope method provides a way of integrating the spatial and temporal complexities of the flow field around a lake thereby offering an appealing alternative to the traditional time and labor intensive methods using seepage meters and an extensive piezometer network in this paper the method is applied to a lake in northern wisconsin demonstrating that it can be successfully applied to lakes in the upper midwest where thousands of similar lakes exist inflow and outflow rates calculated for the wisconsin lake using the isotope mass balance method are 29 and 54 cm yr respectively which compare well to estimates derived independently using a three dimensional groundwater flow and solute transport model of 20 and 50 cm yr such a favorable comparison lends confidence to the use of the stable isotope method to estimate groundwater exchange with lakes in addition utilization of stable isotopes in studies of groundwater lake systems lends insight into mixing processes occurring in the unsaturated zone and in the aquifer surrounding the lake and verifies assumed flow paths based on head measurements in piezometers

influence of solar and lunar tides on the mesopause region as observed in polar mesosphere summer echoes characteristics long term observations of polar mesosphere summer echoes pmse from 2002 to 2012 are investigated with the aim to statistically study the effects of solar thermal migrating and lunar gravitational tides on aerosol layers and their environment at altitudes 80 90 km the solar and lunar tidal periodicities are clearly present in pmse data for the first time both amplitudes and phases of solar and lunar tides are estimated using pmse data from the esrad radar located at esrange sweden the diurnal semidiurnal and terdiurnal solar migrating tides show pronounced periodicities in the pmse strength and wind velocity components lunar tides demonstrate clear oscillations in the pmse strength and wind velocities as well canonical lunar gravitational tides corresponding to the lunar gravitational potential produce rather large amplitudes and are comparable to the solar thermal tides whereas noncanonical lunar oscillations have minor effects on pmse layers but are still statistically significant the influence of diurnal semidiurnal tides and monthly semimonthly tidal components is studied separately our estimations of solar thermal and lunar tidal amplitudes are in good agreement with those of previous model and experimental studies a new mechanism of quadratic demodulation of the solar semidiurnal and lunar semidiurnal tides is shown to be valid at the summer mesopause and can explain periodical pmse oscillations due to the lunar synodic semimonthly tide with period of 14 77 days two harmonics with periods of 27 0 and 13 5 days supposedly representing the solar rotation cycle are also clearly present in pmse data

a global view of the atmospheric lunar semidiurnal tide 1 atmospheric lunar semidiurnal tides are studied using 10 years of temperature data collected by the thermosphere ionosphere mesosphere energetics and dynamics sounding of the atmosphere using broadband emission radiometry satellite the amplitudes and phases in the temperature field are calculated by performing least mean square fit in a data set of about 60 day interval combining ascending and descending data together the mean tidal structures are studied for the height range from 20 to 120 km between 50 latitude and centered on each month from february 2002 to january 2012 a clear signature of the 12 42 h lunar semidiurnal tide is observed in the data characteristic of propagating waves is observed in the vertical amplitude and phase profiles in almost all heights the best conditions of propagation for the lunar semidiurnal tide are reached in the lower thermosphere region asymmetry between the hemispheres and seasonal variability is observed in the amplitudes of the tide longitudinal variations are also observed which reveals the existence of nonmigrating components in addition to the dominant migrating lunar tide

the use of environmental tracers to determine focused recharge from a saline disposal basin and irrigation channels in a semiarid environment in southeastern australia summary lake tutchewop in southeastern australia is a former ephemeral wetland that has been used as a saline disposal basin since 1968 forming part of the salinity management of the murray river the extent of saline focused recharge from lake tutchewop and fresh recharge from nearby unlined irrigation channels was determined using pore water and groundwater stable isotope and major ion chemistry which were able to separate the influence of lake water irrigation water and regional groundwater in 45 years saline water from lake tutchewop has infiltrated only up to 165 m from the lake edge in most directions due to the underlying relatively impermeable clay rich sediments and a maximum of 700 m due to preferential groundwater flow along a sandy palaeochannel the saline leakage has had limited if any impact on surrounding agricultural land use fresh water leakage from unlined irrigation channels extends up to 10 m deep validating the current program to replace these channels with pipelines this study demonstrates that focused recharge from different sources can be positively identified where the recharge waters have distinctive compositions and that underlying clay rich sediments restrict the extent of seepage therefore management of focused recharge sources particularly those that could decrease groundwater quality requires a detailed knowledge of both the groundwater composition around the site and the underlying geology

the water balance of a small lake using stable isotopes and tritium abstract a small maar lake known as the blue lake set in a karstic region of southeastern australia provides the municipal water supply for a population of 20 000 the lake has a volume of 3 6 10 7 m 3 of which 10 15 is pumped from it each year the lake is recharged almost entirely from groundwater and the main objective of this study was to estimate the total groundwater inflow and outflow rates estimation of groundwater throughflow in a lake is difficult to assess using classical hydrological techniques and an alternative method involving measurement of the concentrations of the environmental isotopes 3 h 18 o 2 h and 14 c in the lake water and in the recharging groundwater was used to establish the lake water balance the water balance calculations indicated a total groundwater inflow to blue lake of between 5 0 10 6 and 6 5 10 6 m 3 yr 1 corresponding to a residence time of water in the lake of 6 yr it was not possible to derive the relative proportions of inflow to the lake from the two possible source aquifers using these isotopes because their concentrations did not show a sufficiently large contrast to distinguish the two water sources

onshore geologic storage of co2 the possibility that substantial quantities of co2 can be injected into subsurface porous rock formations has been investigated sufficiently to show that pore space available to contain the co2 is abundant multiple rock types and physical mechanisms can be used to trap the co2 indefinitely with careful site selection and operations leakage to the near surface region can be avoided the next step is to test these injection processes at the scale of a large power plant

multiscale solute transport upscaling for a three dimensional hierarchical porous medium a laboratory generated hierarchical fully heterogeneous aquifer model fhm provides a reference for developing and testing an upscaling approach that integrates large scale connectivity mapping with flow and transport modeling based on the fhm three hydrostratigraphic models hsms that capture lithological static connectivity at different resolutions are created each corresponding to a sedimentary hierarchy under increasing system lnk variances 0 1 1 0 4 5 flow upscaling is first conducted to calculate equivalent hydraulic conductivity for individual connectivity or unit of the hsms given the computed flow fields an instantaneous conservative tracer test is simulated by all models for the hsms two upscaling formulations are tested based on the advection dispersion equation ade implementing space versus time dependent macrodispersivity comparing flow and transport predictions of the hsms against those of the reference model hsms capturing connectivity at increasing resolutions are more accurate although upscaling errors increase with system variance results suggest 1 by explicitly modeling connectivity an enhanced degree of freedom in representing dispersion can improve the ade based upscaled models by capturing non fickian transport of the fhm 2 when connectivity is sufficiently resolved the type of data conditioning used to model transport becomes less critical data conditioning however is influenced by the prediction goal 3 when aquifer is weakly to moderately heterogeneous the upscaled models adequately capture the transport simulation of the fhm despite the existence of hierarchical heterogeneity at smaller scales when aquifer is strongly heterogeneous the upscaled models become less accurate because lithological connectivity cannot adequately capture preferential flows 4 three dimensional transport connectivities of the hierarchical aquifer differ quantitatively from those analyzed for two dimensional systems

a shifting hydrological regime a field investigation of snowmelt runoff processes and their connection to summer base flow sunshine coast british columbia the annual hydrographs of british columbian rivers are either characterized by glacial nival pluvial or hybrid both pluvial and nival sources of runoff climate change scenarios for the 2050s indicate that snow water equivalent swe could diminish by 50 to 80 in lower snowfeddominated basins in the south coastal region of b c compared to historical values this could trigger a shift from a hybrid to a pluvial regime for many creeks originating in the coastal mountains including streams used as primary water supply such as chapman creek on the sunshine coast it has been suggested in previous studies that this change in runoff regime will negatively impact summer low flows due to an earlier onset of snowmelt and a prolonged summer recession period however the connection between groundwater recharge during snowmelt and late summer water yield remains unclear a local headwater catchment stephen s creek was instrumented and monitored from the fall of 2008 to the fall of 2009 a two and a threecomponent isotopic hydrograph separation 2 3 ihs method was developed by adapting the runoff corrected model runce to a semi distributed environment in order to account for spatial variability in snowmelt and in isotopic release from the snowpack ihss results show that event water snowmelt and soil water composed most of the streamflow both at the headwater site 66 19 and at the mouth 62 23 during the peak of the freshet while the contribution of event water to streamflow was significantly different in july 34 11 at the headwater site vs 7 4 at the mouth hydrometric isotopic and geochemical data suggest that saturated throughflow was the predominant flow path taken by melt water during freshet preliminary streamflow recession analysis revealed that the snowmelt recharged headwater catchment can support a steadier summer baseflow than robert s creek a much larger but rainfed dominated watershed it is concluded that the large input of melt water during the spring was sufficient to over turn the shallow subsurface reservoir of the headwater catchment and recharge deeper flow paths at a rate that can not be matched by rainfed dominated systems the results are of interest to water resource planning in the south coastal region

determination of groundwater flow through regimes of shallow lakes and wetlands from numerical analysis of stable isotope and chloride tracer distribution patterns a numerical model previously developed to systematically examine groundwater flow in vertical section near shallow surface water bodies such as lakes wetlands and ponds is further developed to include simulation of the distribution patterns of hydrogeochemical and stable isotopic tracers in relation to the surface water body and the geometry of distribution patterns of the tracers in the groundwater release zone of the lake many different possible flow regimes are identified however in this paper attention is focused on flow through water bodies as these are the flow regimes observed in field validation two shallow lakes on the swan coastal plain of south west western australia are the subject of field studies where hydrogeochemical and stable isotopes are used to validate the flow through groundwater flow regime predicted by the modelling confirming the validity of the approach the flow regime transition diagrams introduced in earlier papers are extended to include consideration of the hydrogeochemical and stable isotopic indices cl l cl and 1000 l 1000 these ratios are introduced as an additional two of nine non dimensional ratios that are necessary to analyse the problem the ratios represent the chloride and isotopic composition ci l and l respectively in the groundwater release zones of the lakes relative to these parameters in the groundwater capture zone cl and for the lake field data from the case studies plotted on appropriately configured transition diagrams demonstrates the overall validity of the modelling approach and its underlying assumptions it is concluded that isotopic and hydrogeochemical data are invaluable in interpreting the interaction between lakes or wetlands and regional aquifers as it is very difficult to make physical or hydraulic measurements in the field that allow an understanding of lake aquifer interaction the tools and concepts developed that are summarized in the presented transition diagrams are invaluable starting points for the consideration and analysis of other case specific examples of groundwater surface water interaction and will improve the scientific basis of decision making concerning lake and wetland management and groundwater interaction by water resource and environmental managers

lunar tidal winds measured in the upper atmosphere 78 105 km at saskatoon canada abstract six years of winds data measured by the partial reflection drifts technique have been analyzed for lunar tides data are available at 3 km intervals of height and are separately analyzed in two year datasets to cheek consistency a month by month seasonal variation is derived largest amplitudes of the lunar tide occur in january february with a smaller maximum in summer the vertical wavelength is longest in summer and the tide then resembles that predicted for a pure 2 2 mode in winter vertical wavelengths range from 25 to 81 km in different years several of these results do not agree with the model of forbes an o1 component of the lunar tide could not be detected

isotope and minor element geochemistry of high arsenic groundwater from hangjinhouqi the hetao plain inner mongolia abstract high as groundwater is widely distributed in the northwestern hetao plain an arid region with slow groundwater flow arsenic concentration in groundwater ranges from 1 to 1000 g l most water samples have elevated salinities with cl and or hco 3 as the dominant anions and na as the dominant cation high concentrations of as in shallow aquifers are associated with strongly reducing conditions as evidenced by high concentrations of dissolved organic c doc nh 4 dissolved sulfide arsenite and dissolved ch 4 and relatively low concentrations of no 3 and so 4 2 results of the hydrochemical and h and o isotope geochemical studies indicate that evapotranspiration is an important process controlling the enrichment of na and cl as well as trace elements such as as b f and br in groundwater in na hco 3 dominated groundwaters as b and f were enriched decades of irrigation using yellow river water has resulted in elevation of the groundwater level which has accelerated salt accumulation in shallow groundwater and surface soil in addition irrigation is responsible for the release of some components from aquifer materials and mixing with saline groundwaters as indicated by minor element and isotope geochemical data used to trace groundwater flow paths sr isotope composition also indicates that bedrock weathering is one of the primary sources of as in groundwater in the study area

streamline based simulation of carbon dioxide storage in a north sea aquifer 1 we model carbon dioxide co2 storage into a deep north sea aquifer using streamline based simulation we assume incompressible flow of liquid like co2 and aqueous phases we simulate dissolution of co2 and a rate limited precipitation reaction advective transport and reactions are solved along streamlines while dispersion and flow due to gravity segregation of the phases are solved on the underlying grid geological storage is modeled on a one million cell model the distribution of co2 after injection is dominated by advective transport due to multiphase flow and co2 moves preferentially through high permeability channels without reaction the regional groundwater flow causes the co2 to continue to migrate until it reaches residual saturation where it continues slowly to dissolve precipitation leads to a decrease in porosity and permeability while co2 is stored in the solid phase the storage efficiency is low around 2 because of aquifer heterogeneity

stable oxygen and hydrogen isotopes as indicators of lake water recharge and evaporation in the lakes of the yinchuan plain the yinchuan plain has more than 2000 years of history of irrigation by diverting water from the yellow river currently the amount of water diverted from the yellow river is about 21 7 times the water formed on the plain as a result of precipitation and inflow of groundwater under the intensive influence of irrigation the plain changed from a desert into a rich and populous area earning its name as south china beyond the great wall with lakes scattered across the yinchuan plain just as stars in the sky in this research 17 representative lakes were sampled to analyze and study 2h and 18o content the results showed that lakes on the plain have undergone obvious non equilibrium evaporation recharges of the lakes can be divided into three types recharge from the yellow river from groundwater and from both of these the craig gordon non equilibrium evaporation model for isotope fractionation was used to estimate the evaporation proportion of each lake the results showed that evaporation from lakes on yinchuan plain is generally extensive under the dry climatic conditions most lakes have an evaporation proportion of over 25 with the largest originating from shahu lake and gaomiaohu lake in the northern part of the plain at 42 5 and 42 8 respectively the evaporation proportions calculated on the basis of 18o and 2h are very close to each other this shows that the method used in this paper is feasible for estimating the evaporation proportions of lakes in areas with a heavy anthropogenic influence copyright 2013 john wiley sons ltd

quantifying closed basin lake temperature and hydrology by inversion of oxygen isotope and trace element paleoclimate records lake systems are important paleoclimate archives that preserve ecosystem and hydrologic responses to critical periods in earth history such as carbon cycle perturbations and glacial interglacial cycles geochemical measurements of biogenic carbonate for example 18o 13c 87sr 86sr li u sr and mg are indicators of hydrologic variability in lake systems throughout the geologic record in this study we present a new closed basin lake modeling approach hybim the hydrologic balance inverse model that employs a system of total differential equations and uses the measured 18o sr ca and mg ca of biogenic carbonate to determine changes in temperature runoff and lake evaporation using equally spaced time steps these equations are simultaneously solved to constrain the hydrologic parameters of the lake as recorded in biogenic carbonate we use a monte carlo approach to account for uncertainty in the input parameters such as 18o temperature relationships partition coefficient uncertainty and watershed solute chemistry for illustrative purposes we apply the model to two ostracod valve datasets covering different timescales 1 the cretaceous songliao basin northeast china and 2 holocene lake miragoane haiti modern water measurements of water isotopes and cation concentrations from each location are required as model inputs we compare our modeling results with author interpretations and geologic observations the modeling approach presented in this study can be applied to other closed basin lake records can be modified for other calcifying species for example gastropods or mollusks or with calibration to inorganic lacustrine carbonate in addition this approach holds promise for extension with additional proxy measurements that is d u ca or li ca and changing source area on tectonic timescales using proxies that reflect changing source lithology that is sr and pb isotopes future incorporation of age model uncertainty in the monte carlo approach will also provide utility by quantifying temporal uncertainty on the hydrologic response recorded by lake sediments

distribution of oxygen and hydrogen isotopes in shallow groundwaters from southern india influence of a dual monsoon system oxygen and hydrogen isotopic investigation of groundwater and river water samples from the southern indian peninsula was undertaken to characterise the isotopic nature of the near surface water sources and provide basic framework for future hydrological studies it is assumed that the shallow groundwater retains the isotopic signature of the local precipitation averaged over a few tens of years except in a few cases where the same gets modified by post precipitation evaporation and or recharge contribution from surface water bodies therefore isotopic character of the groundwater can in principle be used to determine the relative influence of the different vapour sources contributing to the local regional precipitation and to characterise the modifications before groundwater recharge in the present context vapour sources for two rainy seasons namely southwest sw and northeast ne monsoon are respectively the indian ocean arabian sea and the asian continental sources together with the bay of bengal this study shows that i the regions dominated by ne monsoon have distinctly depleted isotopic composition compared to those dominated by sw monsoon ii the 18o d regression line slope of 6 in the east coast region is lower than that expected for local precipitation suggesting secondary evaporation iii the orography of the western ghats hill ranges plays a significant role in controlling the isotopic distribution along the west coast region iv the low d excess values in most part of study area indicate secondary evaporation v the high d excess values over the deccan plateau region in the nw part of the study area suggest admixture of recycled moisture with the inflowing oceanic vapour

handbook of environmental isotope geochemistry vol 1 the terrestrial environment a p fritz and j ch fontes editors elsevier amsterdam 1980 xii 532 pp u s 90 25 dfl 185 00

polar mesosphere summer echoes at wasa antarctica 73 s first observations and comparison with 68 n 1 polar mesosphere summer echoes pmse have been observed for the first time at wasa antarctica 73 s 13 w 61 geomagnetic a new 54 5 mhz radar mara operated first in kiruna 68 n during late summer 2006 and then at wasa between 18 january and 5 february 2007 operation in kiruna allowed accurate cross calibration with the permanent 52 mhz radar esrad pmse at 73 s are found to have very similar characteristics to pmse at 68 n when observations from the same part of the summer season are compared volume reflectivities show very similar distributions over different intensities over height and over local time pmse at 68 n 65 geomagnetic are stronger in the midnight sector likely due to the different geomagnetic latitudes above 85 km altitude weak pmse have a higher occurrence rate at 73 s the height of peak pmse occurrence is 1 km higher at 73 s compared to 68 n

an assessment of the seawater effect by geochemical and isotopic data on the brackish karst groundwater from the karaburun peninsula izmir turkey the study area is located in the center of the karaburun peninsula turkey where several karstic springs discharge near the coast 0 2 m above the sea level the most important discharge points are the ildiri and gerence springs groundwater obtained from ildiri springs and several drill wells provide water to the region during the summer periods the electrical conductivity values are between 1900 and 3900 s cm springs are slightly salty and are not used directly as drinking water salinity was observed in the spring waters under natural flow conditions the salinity values of the drillings and springs were measured in dry and wet seasons spring waters have conductivity values between 3000 and 4000 s cm preliminary surveys reveal that seawater contribution to ildiri springs is 6 5 maximum gerence spring waters discharge to the surface from a region very close to the sea the dominant cation is na and the dominant anion is cl conductivity values were between 7000 and 13 000 s cm gerence spring waters discharge to the sea with seawater contributions ratios between 8 5 and 20 3 depending on the seasonal changes while some spring waters discharge 0 5 1 0 m above sea level the rest of them discharge directly into the sea salinization of gerence spring water is higher than the other springs

atmospheric tide 2 the solar and lunar semidiurnal components solar and lunar semidiurnal wind and temperature oscillations from the surface to 400 km are simulated for average solar activity conditions utilizing the numerical tidal model described in part 1 hough mode decomposition of the solstitial solar semidiurnal tide excited by h2o and o3 insolation absorption below 80 km indicates that it is characterized by a predominance of 2 2 below 60 km about equal contributions of 2 2 2 3 and 2 4 between 70 and 90 km mostly 2 4 with some 2 5 and 2 2 between 90 and 120 km and a predominance of 2 2 above 140 km with secondary contributions from 2 3 and 2 5 the solstitial lunar semidiurnal tide is characterized by a predominance of 2 2 below 70 km 2 4 with secondary contributions from 2 2 2 3 and 2 5 between 80 and 110 km and by 2 2 with a fairly strong secondary contribution from 2 3 above 120 km similar descriptions for both the solar and lunar oscillations apply at equinox except that the asymmetric 2 3 and 2 5 modes are absent relative to the solar component lunar temperature and wind amplitudes are sufficiently large 20 in the lower and upper thermosphere to account for some of the observed variability previously attributed to the solar tide amplitudes of the 2 4 and 2 5 modes above 100 km are significantly affected by mesospheric eddy diffusion coefficients in excess of 2 106 cm s 1 the total solar semidiurnal exospheric temperature oscillation for average solar conditions ranges from 10 20 k poleward of 40 n to 40 60 k equatorward of 30 n and has its origin in three sources of excitation all of comparable importance 1 euv solar radiation absorption in the lower thermosphere 100 200 km 2 in situ momentum coupling due to the interaction of diurnal winds and diurnally varying ion drag and 3 tides propagating upwards from below 100 km in addition the calculations are compared with rocket meteor radar partial reflection thomson scatter and satellite data to evaluate the consistency of the model with observations

evaporative fractions and elevation effects on stable isotopes of high elevation lakes and streams in arid western himalaya summary isotopes of oxygen and hydrogen in water from streams snow and lakes were used to model the ratio of evaporation to total inflow e i of four high elevation lakes in closed basins in the indian himalaya air temperature and relative humidity h data from meteorological stations and global climate grids gmao merra were used as input to the model a second model of the volume of inflow during snowmelt constrained the magnitude of seasonal variability in isotopic composition similar to other areas of the himalaya elevation was a strong determinant of isotopic composition of stream water suggesting that heavier isotopes rain out at lower elevations deuterium excess d in stream water suggests that summer precipitation originating from the bay of bengal rather than winter precipitation from central asia is the dominant source of precipitation for the largest and deepest lakes 15 m e i was 77 87 and 18 50 for two shallow lakes

seasonality and the isotope hydrology of lochnagar a scottish mountain lake implications for palaeoclimate research the relationship between isotope ratios in precipitation and lake waters was monitored by bi weekly measurements taken over a five and a half year period between may 2000 and september 2005 a period of 1964 days at lochnagar a remote mountain lake in eastern scotland short term changes in the oxygen isotope composition of lake water 18ol at lochnagar follow a seasonal pattern similar to isotopes in local precipitation 18op however changes in catchment residence time snow accumulation lake ice cover and lake stratification modify the temporal structure of 18ol over the seasonal cycle of particular importance is precipitation amount which controls catchment and lake residence times and determines the degree of phase lag and amplitude change between 18ol and 18op a simple mass balance model replicates these effects and demonstrates that the degree of phase lag and amplitude reduction is predictable given known input volume ratio the implications of these observations for the use of 18o

geologic modeling and fluid flow simulation of acid gas disposal in western wyoming the moxa arch anticline is a regional scale northwest trending uplift in western wyoming where geologic storage of acid gas carbon dioxide methane nitrogen hydrogen sulfide ethane is under consideration nugget sandstone a deep saline aquifer at depths exceeding 17 000 ft 5180 m is a candidate formation this study builds three dimensional local to regional scale geologic and fluid flow models for the nugget sandstone and its neighboring formations geologic and engineering characterization data were assembled and screened for accuracy using geostatistical simulations first sequential indicator simulation of facies then the sequential gaussian simulation of porosity the data were integrated to create a regional scale geologic model from which a local scale simulation model surrounding the proposed injection si te was extracted using this model acid gas injection was simulated for 50 yr followed by 1950 yr of monitoring a sensitivity analysis was conducted exploring the impact of geologic and engineering variables on model predictions results suggest that at the simulation time scale low dissolved solids in formation water large gas phase relative permeability krg hysteresis and low vertical to horizontal intrinsic permeability k anisotropy all contribute to enhanced storage of acid gas in both residual trapped and dissolved forms the parameter that exerts the largest control on gas storage is relative permeability hysteresis however given parameter uncertainty the total predicted gas storage varies significantly prediction uncertainty increases in the order of dissolved gas trapped gas and mobile gas in comparison petrophysical uncertainty as represented by multiple realizations has limited impact on prediction although future work is needed to expand the uncertainty analysis by developing alternative facies models for the storage formations

reply to comment on estimating groundwater exchange with lakes 1 the stable isotope mass balance method and estimating groundwater exchange with lakes 2 calibration of a three dimensional solute transport model to a stable isotope plume by david p krabbenhoft et al

environmental isotope hydrology of salinized experimental catchments deuterium oxygen 18 tritium and chloride concentrations were used in three salinized experimental catchments to gain insight into the mechanism of solute concentration and flow processes in the saturated and unsaturated zones the three experimental catchments were studied because of their location in different rainfall regions their status with respect to clearing of native vegetation and with respect to secondary salinization two uncleared catchments have average annual rainfalls of approximately 820 and 1220 mm respectively the third cleared catchment has an annual rainfall of 650 750 mm this catchment was in an advanced state of secondary salinization and displayed large areas of saline groundwater discharge with halite encrustation at the ground surface the stable isotope compositions of the solution phase in solute bulge profiles in the unsaturated zone showed a close agreement with the amount weighted mean isotopic composition of rainfall and only surficial evidence of isotopic enrichment due to evaporation evaporation from the soil surface plays a minor role as a mechanism of solute concentration in the unsaturated zone the dominant process of solute concentration in the unsaturated zone was ion exclusion during uptake of water by tree roots which was evidently a solute but not isotope fractionating process tritium analyses of unsaturated zone water and grondwater indicated movement of recent recharge to 7 10 m depth at the low rainfall site but over the full depth of the 15 m unsaturated zone at the higher rainfall site the variability in 18o and 2h values of groundwaters was used in association with chloride concentrations to provide information on mixing characteristics of groundwaters within the catchments

transient hydrogeological controls on the chemistry of a seepage lake a solute mass balance method was used to estimate groundwater inflow and outflow rates for nevins lake michigan a seepage lake in the upper peninsula that historically has shown extremely variable water chemistry compared with most other seepage lakes a 4 year study 1989 1992 of the hydrology and geochemistry of nevins lake and its contiguous groundwater system revealed that changes in the mass of dissolved solutes are the result of annual hydraulic gradient reversals a pronounced acidification of nevins lake from 1986 to 1988 was likely caused by drought induced diminished groundwater inflow rates in this study dissolved calcium the major cation in water of nevins lake groundwater and precipitation was used for estimating mass flow rates during the 1989 1992 period nevins lake showed a reproducible annual cycle in calcium mass immediately following spring snowmelt and the resulting hydraulic gradient reversal the mass of dissolved calcium in the lake increases rapidly and then it decreases steadily throughout the summer and early fall at which time the lake becomes hydraulically mounded and receives no groundwater inflow groundwater flow rates estimated by the solute mass balance method are sensitive to assumed solute concentrations in discharging groundwater pore water samples from the lake bed are shown to be more representative of water discharging to the lake than are samples from piezometers near the lake shore but spatial and temporal variability in pore water chemistry must be considered stable isotope analyses 18o and 2h of lake water groundwater and pore water samples show that water discharging to nevins lake in the spring is entirely recycled lake water and no groundwater derived from terrestrial recharge reaches the lake the conceptual model formulated during this study linking lake chemistry and the contiguous groundwater system and general groundwater flow patterns surrounding highly transient lake systems are likely transferable to other similar systems

terdiurnal tide in the extended canadian middle atmospheric model cmam 1 we use the extended canadian middle atmosphere model cmam a general circulation model gcm to investigate the nature of the terdiurnal tide temperature and horizontal winds from a model run are analyzed to delineate the character of this tide for zonal wave numbers s 5 to 5 descriptions of the annual mean amplitudes seasonal variations and total tide superposed from the migrating and 10 nonmigrating components are provided the amplitudes and vertical wavelengths of the various components and the total terdiurnal tide are found to depend strongly on season latitude and altitude the migrating terdiurnal component maximizes at mid and high latitudes with significant amplitudes annual mean amplitude in wind temperature 10 m s k in the upper mesosphere and lower thermosphere mlt region between 80 and 100 km maximum amplitudes occur in winter in both hemispheres whereas above 100 km maximum amplitudes occur during solstices for the zonal wind field the nonmigrating terdiurnal components te5 te3 te4 tw4 and tw5 tend to peak at 50 n s with amplitudes between 2 and 8 m s the other nonmigrating components maximize in the polar regions with amplitudes of 2 10 m s possible generation mechanisms solar heating and nonlinear interactions for the migrating terdiurnal tide in the mlt region are also examined correlation analysis indicates that nonlinear interactions between the migrating diurnal and semidiurnal tides are unlikely to be the source of the migrating terdiurnal tide

the springs of lake patzcuaro chemistry salt balance and implications for the water balance of the lake abstract lake patzcuaro the center of the ancient tarascan civilization located in the mexican altiplano west of the city of morelia has neither river input nor outflow the relatively constant lake salinity over the past centuries indicates the lake is in chemical steady state springs of the south shore constitute the primary visible input to the lake so influx and discharge must be via sub lacustrine ground water the authors report on the chemistry and stable isotope composition of the springs deeming them representative of ground water input the springs are dominated by ca mg and na whereas the lake is dominated by na combining these results with previously published precipitation rainfall measurements on the lake the authors calculate the chemical evolution from spring water to lake water and also calculate a salt balance of the ground water lake system comparing cl and 18o compositions in the springs and lake water indicates that 75 80 of the spring water is lost evaporatively during evolution toward lake composition during evaporation ca and mg are lost from the water by carbonate precipitation each liter of spring water discharging into the lake precipitates about 18 7 mg of caco3 salt balance calculations indicate that ground water input to the lake is 85 9 106 m3 a and ground water discharge from the lake is 23 0 106 m3 a thus the discharge is about 27 of the input with the rest balanced by evaporation a calculation of time to reach steady state ab initio indicates that the cl concentration of the present day lake would be reached in about 150 a

a study of conceptual model uncertainty in large scale co2 storage simulation 1 in this study multiscale permeability upscaling is combined with a sensitivity study of model boundary condition to identify an optimal heterogeneity resolution in developing a reservoir model to represent a deep saline aquifer in co2 storage simulation a three dimensional fully heterogeneous reservoir model is built for a deep saline aquifer in western wyoming where each grid cell is identified by multiple material tags on the basis of these tags permeability upscaling is conducted to create three increasingly simpler site models a facies model a layered model and a formation model accuracy of upscaling is evaluated first before co2 simulation is conducted in all models since at the injection site uncertainty exists in the nature of the reservoir compartment end member boundary conditions are evaluated whereby brine production is introduced to control formation fluid pressure the effect of conceptual model uncertainty on model prediction is then assessed for each boundary condition results suggest that for the spatial and temporal scales considered without brine production optimal complexity of the upscaled model depends on the prediction metric of interest the facies model is the most accurate for capturing plume shape fluid pressure and co2 mass profiles while the formation model is adequate for pressure prediction the layered model is not accurate for predicting most of the performance metrics moreover boundary condition impacts fluid pressure and the amount of co2 that can be injected for the boundary conditions tested brine production can modulate fluid pressure affect the direction of mobile gas flow and influence the accuracy of the upscaled models in particular the importance of detailed geologic resolution is weakened when viscous force is strengthened in relation to gravity force when brine production is active variability of the predictions by the upscaled models becomes smaller and the predictions are more accurate suggesting a subtle but important interplay between heterogeneity resolution fluid driving forces and model predictions

practical characterization of eolian reservoirs for development nugget sandstone utah wyoming thrust belt abstract the jurassic eolian nugget sandstone of the utah wyoming thrust belt is a texturally heterogeneous formation with anisotropic reservoir inherited primarily from the depositional environment original reservoir quality has been reduced somewhat by cementation and slightly enhanced by dissolution low permeability gouge filled micro faults compartmentalize the formation whereas intermittently open fractures provide effective permeability paths locally where productive the nugget sandstone ranges from approximately 800 to 1050 ft 244 320 m thick at subsurface depths of 7500 to 15 000 ft 2286 4572 m porosity ranges from several percent to 25 and permeability covers five orders of magnitude from hundredths of millidarcies to darcies some nugget reservoirs are fully charged with hydrocarbons different stratification types have unique depositional textures primary and diagenetic mineralogies and deformational fabrics resulting in characteristic porosity permeability permeability directionality and pore geometry attributes such characteristics can be determined from core analysis mercury injection nuclear magnetic resonance conventional log dipmeter and production data nugget dune deposits good reservoir facies primarily consist of grainflow and wind ripple cross strata the former of which have the better reservoir quality and the lesser heterogeneity in bedding texture high permeability facies are commonly affected by local quartz and nodular carbonate cementation chlorite and lesser illite precipitation and minor framework and cement dissolution gouge filled micro faults are the predominant deformational overprint interdune sand sheet and other water associated deposits poor reservoir facies are characterized by low angle wind ripple laminae and more irregular bedding some of which is associated with damp or wet conditions water associated nugget stratification generally contains the finest grained depositional textures and has the poorest reservoir properties these non dune facies contain intergranular micritic carbonate and illite precipitates and are most affected by compaction and pressure solution phenomena open types of fractures are somewhat more likely in this lower permeability rock depositional models incorporating dune morphologies facies distribution permeability directionality and theoretical concepts regarding dune migration through time are useful in delineating correlative intervals most likely to have continuity and potential communication of reservoir properties stratigraphic models can be adapted for reservoir simulation studies and also can be utilized in solving structural resolution problems if correlatable vertical sequences and relatively consistent cross strata orientations exist

constraining groundwater discharge in a large watershed integrated isotopic hydraulic and thermal data from the canadian shield or a thin veneer of coarse grained sediments natural conservative d 2 h d 18 o cl and specific conductance radioactive 222 rn and thermal tracers are integrated with streamflow measurements and a steady state advective model to delimit the discharge locations and quantify the discharge fluxes to lakes wetlands creeks and the tay river the groundwater discharge rates to most surface water body types are low indicating that the groundwater and surface water system may be largely decoupled in this watershed compared to watersheds underlain by porous media groundwater discharge is distributed across the watershed rather than localized around lineaments or high density zones of exposed brittle fractures the results improve our understanding of the rate localization and conceptualization of discharge in a large fractured rock watershed applying hydraulic isotopic or chemical hydrograph separation techniques would be difficult because the groundwater discharge signal is small compared to the background surface water inflows or volumes of the surface water bodies although this study focuses on a large watershed underlain by fractured bedrock the methodology developed is transferable to any large regulated or unregulated watershed the low groundwater discharge rates have significant implications for the ecology sustainability and management of large crystalline watersheds

investigating the interaction between crescent spring and groundwater in a chinese dune lake environment using hydraulic gradient and isotope analysis methods this paper investigates the interaction between groundwater and groundwater dominated crescent spring in an aeolian sand environment to determine the drainage source of groundwater for the lake using hydraulic gradient and isotope analysis methods the precipitation is found to have an insignificant effect on the lake in an arid climate environment hydrogen and oxygen isotopic evidence presents at least two aquifer contributions that recharge 87 and 13 water supply of the lake respectively the flow direction of groundwater is theoretically established based on the hydraulic gradient and isotope analysis methods

estimating groundwater exchange with lakes 2 calibration of a three dimensional solute transport model to a stable isotope plume a three dimensional groundwater flow and solute transport model was calibrated to a plume of water described by measurements of 18o and used to calculate groundwater inflow and outflow rates at a lake in northern wisconsin the flow model was calibrated to observed hydraulic gradients and estimated recharge rates calibration of the solute transport submodel to the configuration of a stable isotope 18o plume in the contiguous aquifer on the downgradient side of the lake provides additional data to constrain the model a good match between observed and simulated temporal variations in plume configuration indicates that the model closely simulated the dynamics of the real system the model provides information on natural variations of rates of groundwater inflow lake water outflow and recharge to the water table inflow and outflow estimates compare favorably with estimates derived by the isotope mass balance method krabbenhoft et al this issue model simulations agree with field observations that show groundwater inflow rates are more sensitive to seasonal variations in recharge than outflow

a six year isotopic record of lake evaporation at a mine site in the canadian subarctic results and validation an isotopic method is applied in conjunction with a water balance method and the penman combination method to estimate evaporation from a small high closure low outflow lake near yellowknife northwest territories canada 62803 0 n 111824 0 w the study provides baseline hydrological information for assessment of tailings pond design and management at nearby mine sites and notably enables intercomparison of several field based evaporation methods and a standard climate approach in a subarctic setting a non steady isotope mass balance method is applied to estimate evaporation over time intervals ranging from five days to three weeks based on isotopic surveys of lakewater groundwater precipitation and atmospheric moisture during the open water periods of 1991 to 1996 use of a relatively high precision non steady technique in contrast to the commonly employed approach assuming steady state is feasible in the present setting owing to pronounced seasonal evaporative enrichment in lake water 20 30 times analytical uncertainty of d 18 o a comparative analysis reveals that the isotopic method is conservative relative to the penman combination method but less conservative than standard water balance although estimates for the open water period are in agreement to within 20 in both cases interannual variability in evaporation is revealed to be 30 50 greater than predicted from standard pan to lake algorithms and of the same order of magnitude as the annual snow water equivalent 155 175 mm which has important implications for the design and management of tailings ponds in the area 1998 john wiley sons ltd