influence of the north pacific victoria mode on the pacific itcz summer precipitation this study demonstrates the close connection between the second dominant mode of spring sea surface temperature anomalies sstas in the north pacific poleward of 20 n referred to as the victoria mode vm and the pacific intertropical convergence zone itcz precipitation during the following summer our analysis shows that strong positive vm cases are followed by positive precipitation anomalies over the central eastern pacific itcz region in association with negative precipitation anomalies over the itcz regions of the tropical western pacific and eastern north pacific the hypothesized physical mechanism through which the spring vm induces the pacific itcz summer precipitation is similar to but slightly different from the seasonal footprinting mechanism during strong positive vm cases sstas in the subtropics associated with the spring vm persist until summer and develop toward the equator where low level convergence and divergence caused by ssta gradients give rise to enhanced precipitation over the central eastern pacific itcz region and to reduced precipitation over the itcz regions of the tropical western pacific and eastern north pacific the thermodynamic ocean atmosphere coupling between the itcz and sstas associated with the vm may play a vital role in the initiation of el nino southern oscillation enso events the vm influence on tropical pacific summer precipitation can be passed on to the next year through its influence on enso a vm based linear model is established to predict the tropical pacific summer precipitation which yields skillful forecasts for summer precipitation across almost the entire tropical pacific

louann salt geochemistry gulf of mexico sedimentary basin u s a a preliminary synthesis abstract samples of jurassic salt and anhydrite were obtained from throughout the gulf of mexico sedimentary basin salt samples have been analyzed for bromide content and 87 sr 86 sr of anhydrite inclusions and anhydrite for 87 sr 86 sr most samples of diapiric salt contain 87 sr 86 sr ratios are commonly radiogenic relative to the ratio in presumed coeval jurassic callovian seawater both these observations suggest that during deformation salt undergoes extensive rock water interaction losing bromide to the reacting brines and incorporating radiogenic sr similar behavior of anhydrite during deformation with respect to sr is also observed samples of deeply buried salt exhibit bromide concentrations consistent with the precipitation of marine halite but include several samples with extremely high values few 87 sr 86 sr ratios however seem to be characteristic of coeval callovian seawater samples with normal bromide content but radiogenic sr suggest primary deposition from or recrystallization in the presence of radiogenic fluids with marine like bromide content samples with extremely high bromide content and radiogenic sr values suggest recrystallization in fluids with elevated bromide content due to loss of bittern phases or extensive rock water interaction of bedded salt during deep burial the data suggest a dynamic system in which physical modification of evaporites during deformation and deep burial is accompanied by chemical modification

convection in the east pacific intertropical convergence zone the eastern tropical pacific exhibits a strong cross equatorial sea surface temperature sst gradient which drives a southerly flow in the atmospheric boundary layer convergence in this flow is generally considered to drive deep convection in the east pacific intertropical convergence zone however results from cloud modeling and recent field programs provide an alternative thermodynamic mechanism for controlling this convection while shallow convection responds to boundary layer convergence deep convection appears to be controlled by a combination of convective inhibition surface moist entropy fluxes tropospheric relative humidity and moist convective instability these factors explain the sharp minimum in infrared brightness temperature near 8 n while boundary layer convergence occurs over a much broader range of latitudes

regional trends in water chemistry smackover formation southwest arkansas geochemical and physical controls we present results on regional geochemical analyses of formation waters from jurassic carbonate strata of the upper smackover formation from the southwest arkansas shelf gulf coast basin these formation waters have been noted in earlier studies for their exceptional salinities and abnormally br rich composition our detailed and regionally extensive database shows that chemical heterogeneities occur on a relatively small scale and have spatial relations to faults which may act as pathways for fluid migration from deeper and hotter portions of the stratigraphic section one of the most pronounced heterogeneities in water chemistry is an h 2 s rich anomaly in the center of the shelf enrichments in h 2 s are accompanied by large increases in alkali elements li k and b and b which could be produced by higher temperature diagenesis of clay minerals and feldspars in deeper seated siliciclastic strata bromide enrichments in all smackover formation waters are apparent from relations between br and cl contents as well as br and divalent cation carpenter function values as suggested by earlier studies of these waters evaporatively concentrated seawater expelled from associated thick monomineralic evaporite sections may be an important source of br cl and na whereas ca mg and sr concentrations have been modified by carbonate mineral recrystallization and dolomitization mineral equilibria exert significant controls on concentrations of ca mg sr and so 4 in these brines br enrichment likely was produced by halite recrystallization in fluids already enriched in br from seawater evaporation elevated cl br ratios occur in regional association with lower salinity water near t e south arkansas fault system consistent with halite dissolution during meteoric water recharge thus despite relatively uniform reservoir lithology and simple structural setting processes on small spatial scales have resulted in significant heterogeneity in water chemistry within a small area of the gulf coast sedimentary basin although movement of fluids along these fault systems is not demonstrated in our study the regional trends in geochemistry are strongly suggestive of their important role in controlling chemical heterogeneities in smackover formation waters

case studies of developing east pacific easterly waves this paper contains a study of developing east pacific easterly waves observed during the summer of 1991 with aircraft in situ and radar data and geosynchronous infrared satellite imagery the circulation and divergence profiles surface momentum and entropy fluxes as well as 700 mb and 975 mb saturated and actual equivalent potential temperatures were measured repeatedly for three disturbances that evolved into east pacific hurricanes as the disturbances develop the level of maximum updraught mass flux decreases which leads to increased convergence at low levels this process appears to be coupled to an increase in the mid level relative humidity which in turn suppresses the development of convective downdraughts comparison of the respective tendencies of convergence and surface friction to spin up and spin down a developing disturbance suggests that friction is unimportant in the early stages of development however as the surface circulation develops the two effects become comparable in magnitude if surface friction is deposited through a fairly deep layer of the troposphere the observations appear to rule out boundary layer ekman balance in these developing systems though more accurate observations of the eddy fluxes of absolute vorticity into such systems are needed to answer this question with certainty

daily states of the march april east pacific itcz in three decades of high resolution satellite data abstractzonally elongated areas of cloudiness that make up the east pacific intertropical convergence zone itcz can take on several configurations in instantaneous observations a novel statistical model is used to automatically assess the daily state of the east pacific itcz using infrared satellite images from 1980 to 2012 four itcz states are defined based on itcz location relative to the equator north nitcz and south sitcz of the equator simultaneously north and south of the equator ditcz for double itcz and over the equator eitcz a fifth itcz state is used to classify days when no zonally elongated area of cloudiness is present aitcz for absent itcz the itcz states can occur throughout the year except for the eitcz which is not present during june october with the nitcz state dominating in terms of frequency of occurrence interannual variability of the state distribution is large the most striking variability in itcz states is observed in spring during march april the ditcz

origin and chemical evolution of formation waters from silurian devonian strata in the illinois basin usa abstract a suite of formation water samples from silurian devonian reservoirs in the illinois basin has been analyzed for major minor and trace element concentrations and for h o and sr isotopic compositions in order to interpret origin of salinity and geochemical evolution of brine compositions in this evaporite and shale poor cratonic basin although chloride concentrations range from 2000 to 137 000 mg l cl br ratios 291 18 are consistent with those of seawater or seawater evaporated short of halite saturation cl br 292 thus during silurian devonian time subaerially evaporated penesaline brine entered the subsurface where it was chemically modified through brine rock interactions cation br ratios and mineralogy of associated strata indicate that na and k were depleted through interaction with clay minerals ca was enriched and mg depleted by dolomitization and sr was enriched as a result of caco3 recrystallization and dolomitization although significant dilution of the modified brine with meteoric water is supported by d 18o covariance original marine waters have not been completely expelled from silurian devonian strata hydrogen and oxygen isotopes exhibit covariant relations with cation and anion concentrations implying that isotopic exchange between h2o and minerals has not greatly influenced the d 18o trend brine 87 sr 86 sr ratios range from 0 7092 to 0 7108 when these ratios are plotted versus 1 sr a two component mixing trend is suggested although sr concentrations have experienced local diagenetic modification a 87sr enriched fluid may have accompanied petroleum migration from new albany shales into adjacent silurian devonian carbonates where it mixed with remnant evaporated seawater this event probably preceded the influx of meteoric water as gdd and 18o are not correlated with sr isotopic compositions of formation waters

connections between potential vorticity intrusions and convection in the eastern tropical pacific abstract the connections between intrusions of stratospheric air into the upper troposphere and deep convection in the tropical eastern pacific are examined using a combination of data analysis potential vorticity pv inversion and numerical simulations analysis of ncep ncar reanalyses and satellite measurements of outgoing longwave radiation during intrusion events shows increased cloudiness lower static stability upward motion and a buildup of convective available potential energy cape at the leading edge of the intruding tongue of high pv potential inversion inversion calculations show that the upper level pv makes the dominant contribution to the changes in the quantities that characterize convection this supports the hypothesis that upper level pv anomalies initiate and support convection by destabilizing the lower troposphere and causing upward motion ahead on the pv tongue the dominant role of the upper level pv is confirmed by simulations using the fifth generation pennsylvania state u

detecting the itcz in instantaneous satellite data using spatiotemporal statistical modeling itcz climatology in the east pacific abstract a markov random field mrf statistical model is introduced developed and validated for detecting the east pacific intertropical convergence zone in instantaneous satellite data from may through october the mrf statistical model uses satellite data at a given location as well as information from its neighboring points in time and space to decide whether the given point is classified as itcz or non itcz two different labels of itcz occurrence are produced ir only labels result from running the model with 3 hourly infrared data available for a 30 yr period 1980 2009 all data labels result from running the model with additional satellite data visible and total precipitable water available from 1995 to 2008 ir only labels detect less area of itcz than all data labels especially where the itcz is shallower yet qualitatively the results for the two sets of labels are similar the seasonal distribution of the itcz through the summer half year is presented showing typical location and e

marine boundary layers associated with ocean upwelling over the eastern equatorial pacific ocean this paper deals with structure and processes in the marine boundary layer along air mass trajectories over and in the vicinity of the cold water tongue of the eastern equatorial pacific ocean the study is based on three nasa p3 b aircraft missions from guayaquil ecuador part of the nasa pacific exploratory mission tropics experiment the observations were made during september 1996 which is part of the cold season when the lowest sea surface temperatures are expected the boundary layer and the overlying free troposphere showed several unique features not observed previously while the boundary layer was advected over the equatorial cold tongue toward the intertropical convergence zone the overlying free tropospheric air consisted of warm moist outflow from the south american continent where deep convection was taking place the specific humidity just above the inversion was typically i 2 g kg t higher than that in the boundary layer these conditions tend to suppress cloud top radiative cooling and entrainment at the boundary layer top over the coldest upwelling areas shallow thermal internal boundary layers were observed we discuss changes in cloudiness sensible and latent heat fluxes and the scale of turbulence in and above the thermal internal boundary layers and during the reestablishment of the convective boundary layer upon passing over a warmer sea surface ularly during the cold season when as will be shown the mbl displays some rather unique characteristics reflecting the influence of cold ocean upwelling and a warm moist continental outflow in the overlying free troposphere these observations provide a basis for un derstanding transport and mixing of trace species and the formation and dissipation of clouds in this area and season both of these topics have implications for cli mate research we focus on data from the nasa p3 b research air craft collected during flights from guayaquil ecuador the area covered is adjacent to and se of the area in vestigated using dropwinsondes in the first global at mospheric research program garp global experi

formation and chemical evolution of magnesium chloride brines by evaporite dissolution processes implications for evaporite geochemistry abstract the evolution of magnesium chloride brines with high bromide contents via a multistage reaction and dissolution process has been studied in brine seeps of a german potash mine the observed chemical trends and phase equilibria can be modeled and interpreted in terms of a nacl solution cap rock brine infiltrating into a potash zone characterized by the metamorphic mineral assemblage kieserite sylvite halite anhydrite establishment of a persistent stable equilibrium assemblage and constant fluid composition in the invariant point ip1 of the six component na k mg ca cl so4 h2o system of oceanic salts is prevented by the perpetually renewed input of nacl brine and by the intermittent exposure of incompatible kieserite instead the solutions develop towards the metastable invariant point ip1 gy with the mineral assemblage carnallite polyhalite sylvite halite gypsum where gypsum takes the place of anhydrite stage i the temporary exposure of kieserite and the ensuing formation of polyhalite effectively buffer the solutions along the metastable polyhalite phase boundary during stages ii and iii eventually in stage iv polyhalite becomes depleted and admixture of more nacl brine leads to low sulfate solution compositions which are now only constrained by carnallite sylvite halite and the once hexary system degenerates to a quaternary one na k mg cl h2o in point e bromide in brines shows equilibrium partitioning with respect to the wall rock minerals the pattern of evolving brine compositions may serve as a model for similar brine occurrences which in some cases may have been misinterpreted as remains of fossil highly concentrated and chemically modified seawater similar magnesium chloride brines of salt lakes e g dead sea dabusun lake show subtle differences and are constrained by fewer mineral equilibria more degrees of freedom and their low sulfate contents are due to gypsum precipitation driven by calcium chloride input from dolomitization reactions finally the observed reaction sequence is generalized and a model for the formation of magnesium sulfate depleted chloride type potash salts and bischofite deposits by leaching of sulfate type evaporites is proposed

genetic and temporal relations between formation waters and biogenic methane upper devonian antrim shale michigan basin usa abstract controversy remains regarding how well geochemical criteria can distinguish microbial from thermogenic methane natural gas in most conventional deposits has migrated from a source rock to a reservoir rarely remaining associated with the original or cogenetic formation waters we investigated an unusual gas reservoir the late devonian antrim shale in which large volumes of variably saline water are coproduced with gas the antrim shale is organic rich of relatively low thermal maturity extensively fractured and is both source and reservoir for methane that is generated dominantly by microbial activity this hydrogeologic setting permits integration of chemical and isotopic compositions of coproduced water and gas providing a unique opportunity to characterize methane generating mechanisms the well developed fracture network provides a conduit for gas and water mass transport within the antrim shale and allows invasion of meteoric water from overlying aquifers in the glacial drift steep regional concentration gradients in chemical and isotopic data are observed for formation waters and gases dilute waters grade into dense brines 300 000 ppm over lateral distances of less than 30 km radiogenic 14c and 3h and stable isotope 18o and d analyses of shallow antrim shale formation waters and glacial drift groundwaters indicate recharge times from modern to 20 000 yr bp carbon isotope compositions of methane from antrim shale wells are typical of the established range for thermogenic or mixed gas 13c 47 to 56 however the unusually high 13c values of co2 coproduced with methane 22 and dissolved inorganic carbon dic in formation waters 28 require bacterial mediation the d values of methane and coproduced formation water provide the strongest evidence of bacterial methanogenesis methane ethane propane ratios and 13c values for ethane indicate 1 the presence of a thermogenic gas component that increases basinward and 2 progressive bacterial oxidation of ethane as the antrim shale subcrop is approached multiple episodes of pleistocene glaciation over northern michigan appear critical to the development of these gas deposits loading of thick ice sheets may have provided hydraulic head that enhanced dilation of preexisting fractures and influx of meteoric water the physical erosion cycle of repeated glacial advances and retreats exhumed the antrim shale around the northern margin of the michigan basin subjecting it to near surface physiochemical and biochemical processes the chemical and hydrologic relations demonstrated in the antrim shale reservoir suggest a dynamic connection between pleistocene glacial history of the midcontinent region and development of recoverable microbially generated natural gas reserves

convective forcing in the intertropical convergence zone of the eastern pacific abstract one of the goals of the east pacific investigation of climate year 2001 process study epic2001 was to understand the mechanisms controlling the forcing of deep atmospheric convection over the tropical eastern pacific an intensive study was made of convection in a 4 4 square centered on 10 n 95 w in september and october of 2001 this is called the intertropical convergence zone itcz study region because it encompasses the eastern pacific intertropical convergence zone starting from an analysis of the theoretical possibilities and a plethora of dropsonde in situ radar and satellite data it is found that newly developing convection occurs where a deep layer of air of order 1 km deep or deeper is conditionally unstable with only weak convective inhibition shallower conditionally unstable layers are associated with numerous small clouds but do not seem to produce deep convection the occurrence of deep convection over the itcz study region is presumably related to the propensity

the interaction of clouds and dry air in the eastern tropical pacific cloud radar observations of eastern pacific intertropical convergence zone cloud vertical structure are interpreted in light of soundings 100 km scale divergence profiles calculated from precipitation radar doppler velocities and surface rain gauge data from a ship at 10 n 95 w during the 2001 east pacific investigation of climate epic experiment the transition from convective to stratiform rain is clear in all four datasets indicating a coherence from local to 100 km scale a novel finding is dry air intrusions at altitudes of 6 8 km often undercutting upper level ice clouds two distinct dry air source regions are identified one is a relatively dry area overlying the cooler waters of the costa rica oceanic thermocline dome centered approximately 400 km east northeast of the ship site the other is the even drier nearequatorial subsidence zone south of 6 7 n the former source is somewhat peculiar to this specific ship location so that the ship sample is not entirely representative of the region the 20 25 september period is studied in detail as it depicts two influences of the dry air on cloud vertical structure one is the modulation of small scale surface based convection evident as a weakening and narrowing of cloud radar reflectivity features the other springs from intense sublimation cooling as differential advection brought snowing anvil clouds over the dry layers during one half day period of strong sublimation the cooling rate is inferred to be several tens of degrees per day over a 100 hpa layer based on a heat budget estimate at 100 km scale involving the horizontal wind divergence data this is consistent with fluxing ice water contents of 0 05 0 10 g m 3 derived from the cloud radar reflectivities the temperature profile shows the dynamically expected response to this cooling a positive negative positive temperature anomaly pattern centered on the sublimating layer a buoyancy sorting diagnostic model of convection indicates that these upper troposphere temperature anomalies can cause premature detrainment of updrafts into the lower part of the cloudy layer a feedback that may actively maintain these long lasting dense anvils middle troposphere southerly dry air inflow is also evident in large scale analysis given the proximity of the dry equatorial subsidence zone to the eastern tropical pacific the differential advection of dry and cloudy air the ensuing sublimation and its dynamical aftereffects may play a role in establishing the region s climate although the extent of their significance needs to be further established

geochemistry and hydrodynamics of deep basin brines palo duro basin texas u s a abstract permeable strata of the deep basin brine aquifer system underlie bedded permian evaporites in the palo duro basin texas panhandle formation water samples collected from four u s department f of energy test wells and two independent oil and gas company wells in the basin were analyzed for chemical and isotopic compositions to characterize the geochemical environment and to determine the origin and compositional evolution of the water formation waters are na cl brines that contain 140 to 290 g l total dissolved solids tds chemical and isotopic compositions suggest grouping the brine samples into one of two types samples from western palo duro basin have high cl br ratios sr isotopic ratios that are significantly more radiogenic than permian seawater or precipitates from permian seawater and oxygen isotopic compositions that are depleted with respect to values predicted for equilibrium with calcite under in situ conditions samples from central and eastern palo duro basin have low cl br ratios sr isotopic ratios only slightly radiogenic relative to permian marine sr and oxygen isotopic compositions that suggest equilibration with calcite the concentrations of major and minor ions appear to be controlled by equilibrium with calcite dolomite anhydrite celestite low albite microcline and na smectite high na activities drive ion exchange reactions which coupled with maintenance of chemical equilibrium elevate the concentrations of divalent cations and lower the concentrations of dissolved so 4 and carbonate the origin and evolution of deep basin brines are interpreted from chemical and isotopic compositions integrated with results of previous geological and hydrogeological investigations brines from western palo duro basin acquired salinity by dissolving halite along a lateral flow path from the recharge zone radiogenic sr was derived from detrital silicate minerals and oxygen isotopic equilibrium with aquifer minerals has not been attained brines from central and eastern palo duro basin originated as either recharge that achieved chemical and isotopic equilibrium with the host rock during long residence times or as permian seawater concentrated by evaporation regional chemical and isotopic variations augment the results of hydrogeological modeling brines in the western part of the basin flow from the west and southwest where siliciclastic sedimentary rocks predominate brines in the central and eastern parts of the basin flow from the south and southwest where carbonate strata predominate

the role of environmental shear and thermodynamic conditions in determining the structure and evolution of mesoscale convective systems during toga coare abstract a collection of case studies is used to elucidate the influence of environmental soundings on the structure and evolution of the convection in the mesoscale convective systems sampled by the turboprop aircraft in the tropical ocean global atmosphere toga coupled ocean atmosphere response experiment coare the soundings were constructed primarily from aircraft data below 5 6 km and primarily from radiosonde data at higher altitudes the well documented role of the vertical shear of the horizontal wind in determining the mesoscale structure of tropical convection is confirmed and extended as noted by earlier investigators nearly all convective bands occurring in environments with appreciable shear below a low level wind maximum are oriented nearly normal to the shear beneath the wind maximum and propagate in the direction of the low level shear at a speed close to the wind maximum when there is appreciable shear at middle levels 800 400 mb convective bands form parallel to the shear with

the structure of the atmospheric boundary layer in the central equatorial pacific during january and february of fgge abstract the structure of the atmospheric boundary layer for a region between hawaii and the equator is studied using dropwindsonde data 900 soundings collected in january and february 1979 as part of the first garp global experiment these data were used to establish the longitudinal and latitudinal variations in the thermodynamic and wind structure of the boundary layer and describe differences in the structure for convectively active and inactive conditions low level inversions at a pressure of approximately 850 mb were found to be an important feature of the structure of the boundary layer for undisturbed conditions although the frequency of low level inversions decreased equatorward from hawaii the average height of the inversions observed in these regions did not vary significantly in the north south direction for convectively undisturbed conditions low level inversions are on the average of sufficient strength to suppress deep convection however it is shown they could easily be modified

spatial variability of atmospheric boundary layer structure over the eastern equatorial pacific abstract variations in the atmospheric boundary layer structure over the eastern equatorial pacific are analyzed using 916 soundings collected during the first global atmospheric research program global experiment unstable boundary layer structures are observed much more frequently in soundings north of the ocean front located near 2 5 n in the eastern equatorial pacific than in soundings south of the front an objective criterion is applied to identify the presence of the transition layer a weak stable layer near cloud base in the soundings the transition is observed in about 45 of the soundings in both the unstable and the inversion categories a comparison of soundings over the cold tongue with those over the itcz indicates that differences in static stability between these regions are limited to the layer from the surface to about 850 mb which is the mean height of the inversions capping the cloud layer over the cold tongue the cold tongue soundings on average are found to be drier from the sur

stable isotope and hydrochemical evolution of groundwater in the semi arid hamersley basin of subtropical northwest australia summary the hamersley basin in the semi arid pilbara region of northwest australia is currently subject to increasing pressure from altered hydrology associated with mining activities as well as water abstraction for regional development sustainable water management across the region must be underpinned by an understanding of the factors that constrain water supply in arid zones we measured the amount and isotopic signature of individual rainfall events over three consecutive years 2009 2011 to determine the likely processes that control surface water pools in streams and groundwater recharge across the hamersley basin we also measured concentrations of ions in particular bromide and chloride to define and quantify sources of major recharge stable isotope composition of precipitation across the basin forms a local meteoric water line lmwl defined by the equation 2h 7 03 0 17 18o 4 78 1 45 thus the slope of the lmwl was similar to the global meteoric water line gmwl however the intercept of the lmwl was significantly different to the gmwl which is attributable to the amount or rainout effect the stable isotope composition of rainfall events was highly variable and dependent on event size however the 2h and 18o values of fresh groundwater from the alluvium and fractured aquifers were similar and characterised by a very narrow range alluvium aquifer 18o 8 02 0 83 2h 55 6 6 0 n 65 fractured aquifer 18o 8 22 0 70 2h 56 9 5 0 n 207 our findings suggest that intense rainfall events of 20 mm with limited evaporation prior to infiltration contribute most to recharge in contrast the 2h and 18o values and chemical composition of the relatively saline groundwater in the terminal fortescue marsh suggest a combination of evaporation and cyclic drying and wetting of the marsh surface prior to recharge saline groundwater samples were more 18o enriched than fresh groundwater 2h and 18o values shifted to the right of the lmwl forming a straight line with a slope of 3 58 0 20 and an intercept of 25 55 0 71 r2 0 95 p

an improved real time global sea surface temperature analysis abstract the monthly global sea surface temperature sst analysis of reynolds using real time in situ and satellite sst data has now been improved by using sea ice data to simulate ssts in ice covered regions the simulated ssts now become the external boundary condition for the analysis solution this technique eliminates any high latitude satellite biases and extends the analysis to the ice edge the analysis with the ice data has been computed for the period january 1982 to present

stoichiometric saturation tests of nacl1 xbrx and kcl1 xbrx stoichiometric saturation is examined as a possible control on br contents of halite and sylvite during precipitation from binary salt solutions of nacl nabr and kcl kbr respectively experimental data at 25 c assumed to represent stoichiometric saturation were used to predict mole fractions of nabr in halite and kbr in sylvite in thermodynamic equilibrium with fluids as a function of aqueous activity ratios of br cl the predictions are based on the additional assumption that the aqueous activity product of the major salt component in the precipitated salt was independent of the trace br content in the salt lattice the extension of the predictions to diagenetic pressures and temperatures is discussed the predicted equilibrium br content of halite at initial halite saturation of evaporating seawater is in close agreement with that computed from the distribution coefficient of lutz 1975 measured in slowgrowth single crystal experiments fluid recrystallization of halite and sylvite at near surface temperatures is predicted to generally deplete the br contents in the solids bulk br contents in halite in cap rock of gulf coast salt domes generally agree with those predicted by the recrystallization of halite in the presence of evaporative concentrated seawater at a constant solution composition increasing temperature results in increasing the equilibrium br content of halite making less efficient br depletion in halite by recrystallization

geochemistry of metal rich brines from central mississippi salt dome basin u s a abstract oil field brines are the most favored ore forming solutions for the sediment hosted mississippi valley type ore deposits detailed inorganic and organic chemical and isotope analyses of water and gas samples from six oil fields in central mississippi one of the very few areas with high metal brines were conducted to study the inorganic and organic complexes responsible for the high concentrations of these metals the samples were obtained from production zones consisting of sandstone and limestone that range in depth from 1900 to 4000 m 70 120 c and in age from late cretaceous to late jurassic results show that the waters are dominantly bittern brines related to the louann salt the brines have extremely high salinities that range from 160 000 to 320 000 mg l total dissolved solids and are na ca cl type waters with very high concentrations of ca up to 48 000 mg l and other alkaline earth metals but with low concentrations of aliphatic acid anions the concentrations of metals in many water samples are very high reaching values of 70 mg l for pb 245 mg l for zn 465 mg l for fe and 210 mg l for mn the samples with high metal contents have extremely low concentrations 2 s samples obtained from the smackover formation limestone have low metal contents that are more typical of oil field waters but have very high concentrations up to 85 mg l of h 2 s computations with the geochemical code solmineq 87 give the following results 1 both pb and zn are present predominantly as aqueous chloride complexes mainly as pbcl 4 2 and zncl 4 2 respectively 2 the concentrations of metals complexed with short chained aliphatic acid anions and reduced s species are minor 3 organic acid anions are important in controlling the concentrations of metals because they affect the ph and buffer capacity of the waters at subsurface conditions and 4 galena and sphalerite solubilities control the concentrations of pb and zn in these waters

geochemical and lithium isotope tracking of dissolved solid sources in permian basin carbonate reservoir and overlying aquifer waters at an enhanced oil recovery site northwest texas usa abstract geochemistry and lithium isotope compositions 7li of permian basin produced water and potable groundwater from overlying aquifers at an enhanced oil recovery eor site in gaines county northwest texas are used to evaluate the effects of brine groundwater rock interactions identify sources of dissolved solids and characterize fluid flow and mixing processes 7li values per mil deviations from the lsvec standard 7li 6li ratio for produced water from dolostones of the san andres formation ranged from 10 9 to 15 6 and fall within the range of formation waters from other sandstone carbonate reservoir rocks in north america europe and the middle east these differ from produced waters from hydraulically fractured shales from the u s appalachian basin including the marcellus shale which tend to have lower 7li values and higher li cl possibly indicating greater interaction with a terrigenous component the san andres produced water chemistry and li isotope ratios are consistent with neogene meteoric water interacting with marine and continentally derived evaporites e g portions of the guadalupian salado formation as well as other terrestrial sources along the flow path groundwater from the triassic dockum group santa rosa aquifer 7li range of 20 6 to 23 5 is isotopically distinct from waters from the overlying ogallala formation 10 6 to 16 5 and the deeper san andres formation indicative of hydrologic isolation from both meteoric recharge and from deeper brines in the field area in addition to tracking groundwater brine mixing and water rock interaction temporal changes in the 7li composition of deep groundwater in the study area has potential use in the early detection of upward or injection induced brine migration prior to its incursion into the sensitive overlying ogallala aquifer

chlorine isotope and cl br fractionation in fluids of poas volcano costa rica insight into an active volcanic hydrothermal system abstract halogen rich volcanic fluids issued at the surface carry information on properties and processes operating in shallow hydrothermal systems this paper reports a long term record of cl br concentrations and 37cl signatures of lake water and fumaroles from the active crater of poas volcano costa rica where surface expressions of magmatic hydrothermal activity have shown substantial periodic changes over the last decades both the hyperacid water of its crater lake laguna caliente and subaerial fumaroles show significant temporal variability in cl br concentrations br cl ratios and 37cl reflecting variations in the mode and magnitude of volatile transfer the 37cl signatures of the lake covering the period 1985 2012 show fluctuations between 0 02 0 06 and 1 15 0 09 condensate samples from adjacent fumaroles on the southern shore collected during the interval 2010 2012 with strong changes in gas temperature 107 763 c display a much larger range from 0 43 0 09 to 14 09 0 08 most of the variations in cl isotope br cl and concentration signals can be attributed to interaction between magma derived gas and liquid water in the volcanic hydrothermal system below the crater the 37cl were lowest and closest to magmatic values in 1 fumarolic gas that experienced little or no interaction with subsurface water and followed a relatively dry pathway and 2 water that captured the bulk of magmatic halogen output so that no phase separation could induce fractionation in contrast elevated 37cl can be explained by partial scavenging and fractionation during subsurface gas liquid interaction hence strong cl isotope fractionation leading to very high 37cl in poas fumaroles indicates that they followed a wet pathway highest 37cl values in the lake water were found mostly in periods when it received a significant input from subaqueous fumaroles or when high temperatures and low ph caused hcl evaporation it is concluded that combined monitoring of 37cl and br cl in laguna caliente and adjacent fumaroles provides valuable information on activity in the subsurface hydrothermal system with significant relevance for volcanic surveillance of poas

what controls the transition from shallow to deep convection abstract in this study a 2d cloud system resolving model csrm is used to assess the control mechanism for the transition from shallow to deep convection in the diurnal cycle over land by comparing with a 3d csrm under conditions taken from the large scale biosphere atmosphere field study in the amazon the authors show that the 2d csrm reproduces the main features evident in previous 3d simulations reasonably well to extract the essence of the transition from shallow to deep convection the observed case is idealized to isolate two control parameters the free troposphere stability and the relative humidity the emergence of a distinct transition between shallow and deep convection shows that the convective transition is an intrinsic property of the system a transition time is defined to evaluate the key mechanism of the transition the authors show that the transition coincides with the time when the lapse rate of the virtual potential temperature of the clouds becomes larger than that of the env

tropical south america atlantic sector convective margins and their relationship to low level inflow abstract the edges or margins of tropical convective zones are hypothesized to be sensitive to low level inflow conditions the present study evaluates where and to what extent convective margin variability is sensitive to low level inflow variability using observed precipitation and reanalysis wind and total precipitable water data over the tropical south america atlantic sector in austral summer composite analysis based on an inflow measure defined by projecting low level monthly mean atmospheric boundary layer abl or lower free troposphere lft winds onto either mean horizontal precipitation or precipitable water gradients shows widespread contraction of the edges of convection zones in the direction of stronger convection for anomalously strong low level inflow such behavior is consistent with enhanced import of relatively dry air along the edges of convection zones however the distinction between abl and lft winds may be significant regionally for example along the atlantic itcz s northern m

barometric pressure variations associated with eastern pacific tropical instability waves abstract barometric pressure surface temperature and wind time series in the eastern equatorial pacific are analyzed to determine if oceanic tropical instability wave tiw sea surface temperature variations cause barometric pressure gradients large enough to influence the atmospheric boundary layer during the study period from april 2001 to september 2002 11 tiws propagated westward past 110 w causing a spectral peak at 20 30 days in the sea surface temperature sst meridional difference between 2 n 110 w and 0 110 w likewise the meridional pressure difference also had a spectral peak in the 20 30 day tiw band cross spectral analysis shows that within the tiw band sst induced pressure variations were roughly 0 1 hpa c 1 in magnitude the resulting pressure gradient force is comparable in magnitude to other terms in the meridional momentum balance implications about the role of the boundary layer capping in the adjustment to sst forcing are discussed

geochemistry of fluids from earth s deepest ridge crest hot springs piccard hydrothermal field mid cayman rise abstract hosted in basaltic substrate on the ultra slow spreading mid cayman rise the piccard hydrothermal field is the deepest currently known seafloor hot spring 4957 4987 m due to its great depth the piccard site is an excellent natural system for investigating the influence of extreme pressure on the formation of submarine vent fluids to investigate the role of rock composition and deep circulation conditions on fluid chemistry the abundance and isotopic composition of organic inorganic and dissolved volatile species in high temperature vent fluids at piccard were examined in samples collected in 2012 and 2013 fluids from the beebe vents and beebe woods black smokers vent at a maximum temperature of 398 c at the seafloor however several lines of evidence derived from inorganic chemistry cl sio2 ca br fe cu mn support fluid formation at much higher temperatures in the subsurface these high temperatures potentially in excess of 500 c are attainable due to the great depth of the system our data indicate that a single deep rooted source fluid feeds high temperature vents across the entire piccard field high temperature piccard fluid h2 abundances 19 9 mm are even higher than those observed in many ultramafic influenced systems such as the rainbow 16 mm and the von damm hydrothermal fields 18 2 mm in the case of piccard however these extremely high h2 abundances can be generated from fluid basalt reaction occurring at very high temperatures magmatic and thermogenic sources of carbon in the high temperature black smoker vents are described dissolved co2 is likely of magmatic origin ch4 may originate from a combination of thermogenic sources and leaching of abiotic ch4 from mineral hosted fluid inclusions and co abundances are at equilibrium with the water gas shift reaction longer chained n alkanes c2h6 c3h8 n c4h10 i c4h10 may derive from thermal alteration of dissolved and particulate organic carbon sourced from the original seawater source entrainment of microbial ecosystems peripheral to high temperature venting and or abiotic mantle sources dissolved hcooh in the beebe woods fluid is consistent with thermodynamic equilibrium for abiotic production via co2 reduction with h2 at 354 c measured temperature a lack of hcooh in the relatively higher temperature 398 c beebe vent fluids demonstrates the temperature sensitivity of this equilibrium abundant basaltic seafloor outcrops and the axial location of the vent field along with multiple lines of geochemical evidence support extremely high temperature fluid rock reaction with mafic substrate as the dominant control on piccard fluid chemistry these results expand the known diversity of vent fluid composition with implications for supporting microbiological life in both the modern and ancient ocean

calibration of br cl fractionation during subcritical phase separation of seawater possible halite at 9 to 10 n east pacific rise abstract experiments were conducted to assess br cl fractionatiodn during phase separation of seawater at 400 c and 250 to 275 bars these conditions are applicable to the 9 10 n epr system where low cl concentrations and low br cl rations in vent fluids have been attributed to phase separation of seawater at conditions below the critical point of seawater 408 c 300 bars the level of br cl fractionation observed in experiments is well below that needed to account for br cl systematics at epr 9 10 n based on our experimental results we propose an alternative model involving dissolution and precipitation of halite to account for the anomalous br cl data at 9 10 n halite can be predicted to form at pressure and temperature conditions prevailing during eruption of magma at mid ocean ridges subsequent changes in physical conditions however would induce halite to dissolve and thus decrease br cl ratios of vent fluids

trace element partitioning between vapor brine and halite under extreme phase separation conditions abstract experiments were conducted to investigate the partitioning of li br rb cs and b between vapor brine and halite during subcritical and supercritical phase separation in the nacl h2o system 388 550 c 250 350 bars results indicate that li and br partition preferentially into the low salinity vapor fluids while rb and cs become more enriched in the coexisting brines under more extreme conditions of pressure and temperature in the two phase region especially near the vapor brine halite boundary strong salting out effects imposed on neutral aqueous species enhance significantly partitioning of all trace elements into the low salinity fluid dissolved boron is strongly affected by this and a particularly strong enrichment into vapors is observed a trend that can be effectively correlated with changes in reduced density exclusion of li br rb cs and b from halite when precipitated further increases the solubility of these species in the coexisting cl poor fluid in general the lack of distortion in the partitioning behavior of trace elements between vapor brine and or halite with the transition from subcritical to supercritical conditions in the nacl h2o system precludes the need for special reference to the critical point of seawater when interpreting phase relations in submarine hydrothermal systems the combination of experimentally determined trace element partitioning data with constraints imposed by mineral solubility provides a means to better understand the origin and evolution of hot spring vent fluids for example in brandon hydrothermal system 21 s epr supercritical phase separation and subseafloor mixing appear to be the main heat and mass transport mechanisms fueled by a shallow magmatic intrusion with boron systematics ruling out major contributions from magmatic degassing processes accompanying the near seafloor volcanism

the itcz in the central and eastern pacific on synoptic time scales the itcz in the central and eastern pacific on synoptic time scales is highly dynamic the active season extends roughly from may through october during the active season the itcz continuously breaks down and re forms and produces a series of tropical disturbances the life span of the itcz varies from several days to 3 weeks sixty five cases of itcz breakdown have been visually identified over five active seasons 1999 2003 in three independent datasets itcz breakdown can be triggered by two mechanisms 1 interaction with westward propagating disturbances wpds and 2 the vortex rollup vr mechanism results show that the frequency of occurrence of itcz breakdown from these two mechanisms is the same the vr mechanism may have been neglected because the produced disturbances are rather weak and they may dissipate quickly the itcz shows a strong tendency to re form within 1 2 days in the same location the itcz may break down via the vr mechanism without any other support and thus it may continuously generate numerous tropical disturbances throughout the season there are two main differences between the two mechanisms 1 the wpds induced itcz breakdown tends to create one or two vortices that may be of tropical depression strength the vr induced itcz breakdown generates several nearly equal sized weak disturbances 2 the wpds tend to disturb the itcz in the eastern pacific only disturbances generally move along the mexican coast after shedding off from the itcz and do not further disturb the itcz in the central pacific therefore the vr mechanism is observed more clearly and is the dominating mechanism for itcz breakdown in the central pacific

formation waters from mississippian pennsylvanian reservoirs illinois basin usa chemical and isotopic constraints on evolution and migration we have analyzed a suite of seventy four formation water samples from mississippian and pennsylvanian carbonate and siliciclastic strata in the illinois basin for major minor and trace element concentrations and for strontium isotopic composition a subset of these samples was also analyzed for boron isotopic composition data are used to interpret origin of salinity and chemical and sr isotopic evolution of the brines and in comparison with a similar data set from an earlier study of basin formation waters from silurian devonian reservoirs systematics of cl br na show that present mississippian pennsylvanian brine salinity can be explained by a combination of subaerial seawater evaporation short of halite saturation and subsurface dissolution of halite from an evaporite zone in the middle mississippian st louis limestone along with extensive dilution by mixing with meteoric waters additional diagenetic modifications in the subsurface interpreted from cation br ratios include k depletion through interaction with clay minerals ca enrichment and mg depletion by dolomitization and sr enrichment through caco3 recrystallization and dolomitization ste genevieve limestone middle mississippian formation waters show 87sr86sr ratios in the range 0 70782 0 70900 whereas waters from the siliciclastic reservoirs are in the range 0 70900 0 71052 inverse correlations between 87sr86sr and b li and mg concentrations suggest that the brines acquired radiogenic 87sr through interaction with siliciclastic minerals completely unsystematic relations between 87sr86sr and 1 sr are observed sr concentrations in ste genevieve and aux vases middle mississippian waters appear to be buffered by equilibrium with respect to srso4 although there are many similarities in their origin and evolution these formation waters are distinguished from silurian devonian brines in the basin by elevated clbr and nabr ratios and by unsystematic sr isotope relationships thus waters from these two major segments of the illinois basin stratigraphic column form distinct geochemical regimes which are separated by the new albany shale group devonian mississippian regional aquitard geochemical evolution appears to have been influenced significantly by paleozoic and mesozoic hydrologic flow systems in the basin

low level inversions over the tropical pacific thermodynamic structure of the boundary layer and the above inversion moisture structure abstract the structure of the boundary layer over a broad region of the equatorial pacific is studied using dropwinsonde measurements made in january february may and june of 1979 low level inversions of sufficient strength to inhibit deep convection are found to be present in more than 50 of the soundings these inversions appear to play a critical role in regulating convective activity over the central and eastern pacific the tops of the inversions have an average pressure level of approximately 300 mb and show little latitudinal or longitudinal variation the majority of the inversion soundings approximately 70 have a reversal in the mixing ratio profile qreversal above the inversion that appears as a dry layer at the top of the inversion layer capped by a relatively moist layer this moist layer is on the average 2 g kg 1 more moist than the corresponding soundings that have no qreversal no systematic regional or temporal variations in the frequency of occurrence of the qreversal or the str

on the role of sea surface temperature gradients in forcing low level winds and convergence in the tropics abstract we examine the importance of pressure gradients due to surface temperature gradients to low level p 700 mb flow and convergence in the tropics over time scales 1 month the latter plays a crucial role in determining the distribution of cumulonimbus convection and rainfall our approach is to consider a simple one layer model of the trade cumulus boundary layer wherein surface temperature gradients are mixed vertically consistent with ecmwf analyzed data the top of the layer is taken at 700 mb the influence from higher levels is intentionally suppressed by setting horizontal pressure gradients and frictional stresses to zero at the top of the layer horizontal convergence within the layer is taken up by cumulonimbus mass flux however the development of the cumulonimbus mass flux is associated with a short relaxation time o hr roughly the development time for such convection during this short time horizontal convergence acts to redistribute mass so as to reduce horizontal pressur

variability in the southerly flow into the eastern pacific itcz abstract during boreal summer and fall there is a strong southerly boundary layer flow across the equator into the east pacific intertropical convergence zone itcz the modulation of this flow on synoptic to seasonal time scales is studied using an index of meridional pressure difference between the equator and the itcz along 95 w two complementary datasets from the east pacific investigation of climate epic are used to study eastern pacific variability daily measurements of sea level pressure slp from tropical atmosphere ocean toa array buoys from may to november 2001 provide temporal coverage and eight flights by a c 130 aircraft during september to october 2001 document the associated modulation of lower tropospheric vertical structure the principal mode of variability of the perturbation slp along 95 w from 1 s to 12 n derived by principal component analysis from either the eight flights pc1c 130 or from daily tao buoy observations pc1 explains 77 of the meridional pressure gradien

radar characteristics of precipitation features in the epic and tepps regions of the east pacific abstract ship based radar data are used to compare the structure of precipitation features in two regions of the east pacific where recent field campaigns were conducted the east pacific investigation of climate processes in the coupled ocean atmosphere system epic 2001 10 n 95 w in september 2001 and the tropical eastern pacific process study tepps 8 n 125 w in august 1997 corresponding july september 1998 2004 tropical rainfall measuring mission trmm precipitation radar pr data are also used to provide context for the field campaign data an objective technique is developed to identify precipitation features in the ship and trmm pr data and to develop statistics on horizontal and vertical structure and precipitation characteristics precipitation features were segregated into mesoscale convective system mcs and sub mcs categories based on a contiguous area threshold of 1000 km2 these features were required to have at least one convective pixel as well as an other nc category com

the brine underlying the oak ridge reservation tennessee usa characterization genesis and environmental implications abstract the deep hydrogeologic system underlying the oak ridge atomic reservation contains brine its origin was assessed using existing and newly acquired chemical and isotopic data the proposed model which best fits the data is modification of residual brine from which halite has been precipitated potential sources for this brine are in the appalachian mountains in the east where bedded halite is documented and where the hydraulic gradient needed to move the residual brine exists other models such as ultrafiltration and halite dissolution were also evaluated in places contaminants such as radionuclides heavy metals nitrates and organic compounds have reached the deep system the chemical and isotopic features of the brine were examined with respect to its potential discharge contaminated in places into shallow freshwater systems the observations suggest that whereas the origin of the salts in the brine may be very old influx of recent water takes place consequently the brine is not isolated in terms of recharge and discharge from the overlying active and fresh water bearing units

a laboratory study of the effect of confining pressure on permeable property in soil rock mixture this paper aims at investigating the effect of confining pressure on fluid solid properties in soil and rock mixture srm specimens with different rock block percentage self developed servo permeable testing system was used to carry out the flow stress coupling testing fifty cylindrical srm specimens 50 mm diameter and 100 mm height with staggered rock block proportions 20 30 40 50 60 and 70 by mass were produced by compaction test with different count hammers to roughly insure the same void ratio of soil matrix from the test results the effect of loading and unloading confining pressure on permeability coefficient is discussed permeability coefficient of srm presents decreasing trend with the increase of confining pressure at confining pressure descent stage permeability coefficient begins to increase from the minimum but it is smaller than the confining pressure ascent stage the decreasing rate of permeability coefficient is more rapid than increasing rate in addition the relationship between permeability coefficient and confining pressure follows quadratic polynomial function and the correlation coefficients are greater than 0 98 for all studied srm specimens test results also show that at different hydraulic gradients permeability coefficient increases with time the results show that interaction between soil matrix and rock blocks is the main reason leading to the variation of permeability coefficient

extension of the stochastic mixing model to cumulonimbus clouds abstract the stochastic mixing model of cumulus clouds is extended to the case in which ice and precipitation form a simple cloud microphysical model is adopted in which ice crystals and aggregates are carried along with the updraft whereas raindrops graupel and hail are assumed to immediately fall out the model is then applied to the 2 august 1984 case study of convection over the magdalena mountains of central new mexico with excellent results the formation of ice and precipitation can explain the transition of this system from a cumulus congestus cloud to a thunderstorm

breakdown and reformation of the intertropical convergence zone in a moist atmosphere abstract the effects of moisture on the intertropical convergence zone itcz over the eastern pacific on the synoptic time scale are investigated using an intermediate complexity atmospheric circulation model the quasi equilibrium tropical circulation model qtcm1 on an aquaplanet the dry simulation shows results consistent with those of simple dynamic models except that a slightly stronger heating rate is needed owing to different model designs in the moist simulations the most important result is the formation of a tail southwest of a vortex during and after the itcz breakdown this tail may extend zonally more than 60 longitude and last for more than two weeks in an idealized simulation in the eastern north pacific this phenomenon is often observed in cases that involve easterly waves in a sense the formation of the tail suggests a possible mechanism that forms an itcz efficiently this study shows that the surface convergent flow induced by a disturbance initializes a positive wind evapor

convectively coupled equatorial waves 1 convectively coupled equatorial waves ccews control a substantial fraction of tropical rainfall variability their horizontal structures and dispersion characteristics correspond to matsuno s 1966 solutions of the shallow water equations on an equatorial beta plane namely kelvin equatorial rossby mixed rossby gravity and inertio gravity waves because of moist processes the tilted vertical structures of ccews are complex and their scales do not correspond to that expected from the linear theory of dry waves the dynamical structures and cloud morphology of ccews display a large degree of self similarity over a surprisingly wide range of scales with shallow convection at their leading edge followed by deep convection and then stratiform precipitation mirroring that of individual mesoscale convective complexes ccews have broad impacts within the tropics and their simulation in general circulation models is still problematic although progress has been made using simpler models a complete understanding of ccews remains a challenge in tropical meteorology

the composition of permian seawater forty nine brine inclusions in marine halite from the ochoan salado formation in the delaware basin and fifteen inclusions in halite from the leonardian wellington formation in the kansas basin were extracted and their chemical compositions were determined the brines are of the na k mg cl so4 type their compositions resemble those of evaporated modern seawater the values of mcl mna mbr and mmg2 mca2 mso42 12 mmhco3 mbr of the inclusion brine from the two formations are equal to or slightly higher than those of modern seawater the original mna mbr and mcl mbr ratios of the inclusion brines were probably equal to or slightly larger than those of modern seawater the values of mmg2 mbr of the inclusion brines from the salado formation are very close to that of modern seawater the ratios of inclusion brines from the wellington formation are slightly lower probably due to the formation of dolomite magnesite the mmg2 mbr ratio in the initial seawater was probably close to the parent seawater of the salado brines the values of mso42 mca2 12mhco3 mbr of the inclusion brines appear to be reduced by the formation of dolomite magnesite and the value of this ratio in permian seawater was probably similar to that of modern seawater the mk mbr ratios of the inclusion brines are variable but the original ratios are probably close to or slightly larger than that of modern seawater if the br concentration of permian seawater was equal to that of modern seawater the composition of permian seawater can be narrowly constrained in mmol kg h2o 460 mna 630 550 mcl 730 mmg2 54 6 mk 11 mso2 4 mca2 12mmhco3 17 20 mso42 45 5 mca2 20 and 0 15 mhco3 5 the composition of permian seawater was therefore quite similar to that of modern seawater

the petrogenesis of brines in devonian potash deposits of western canada abstract recent mine level floods in some potash mines in the elk point basin of saskatchewan canada have demonstrated the need to identify accurately the source of water leaks so as to assist in remedial or preventative action most chemical constituents of the waters are inadequate tracers of the origin of these leaks because the concentrations of most elements change substantially during migration of the fluids to the mining level in marked contrast to most of the chemical constituents dissolved in the water oxygen and hydrogen isotopes are conservative elements of the water within the elk point basin d and 18 o values of basinal waters normally increase with depth because of mixing between trapped formation waters and local surface waters such that the water in each aquifer within the basin generally has a unique isotopic composition floodwaters in the potash mines of saskatchewan have chemical and stable isotopic compositions that indicate three different origins for mine level fluids 1 halite and sylvite saturated basinal brines from devonian formations directly above the deposits which are predominantly connate waters 2 undersaturated waters of predominantly meteoric origin from stratigraphically higher aquifers such as the cretaceous mannville group and 3 ca rich brines that may represent devonian fluids associated with recrystallization of the evaporites the salt undersaturated formation waters most likely are directed to lower stratigraphic units through collapse structures or related features which may be reactivated through mining

the genesis of hurricane guillermo texmex analyses and a modeling study abstract the transformation of a mesoscale convective system into hurricane guillermo was captured by aircraft and doppler wind data during the tropical experiment in mexico the early phase of the system evolves in a way very similar to previously documented mesoscale convective systems with a midlevel mesocyclone developing in the stratiform precipitation region more unusually the cyclone extends to low altitudes a weak cyclone is discernable even in the 300 m altitude wind field after another day of evolution a small surface based warm core cyclone is observed to develop within the relatively cold air associated with the mesocyclone aloft this mesocyclone develops into a hurricane over the subsequent day a nonhydrostatic axisymmetric numerical model is used to explore the evolution of the initially cold core midlevel vortex into a tropical cyclone a mesoscale midlevel showerhead is switched on in an initially quiescent tropical atmosphere overlying a warm ocean surface evaporation of t

dynamics of the intertropical convergence zone of the east pacific abstract the dynamical factors controlling the mean state and variability of the east pacific intertropical convergence zone itcz and the associated cross equatorial boundary layer flow are investigated using observations from the east pacific investigation of climate epic2001 project the tropical east pacific exhibits a southerly boundary layer flow that terminates in the itcz this flow is induced by the strong meridional sea surface temperature sst gradient in the region away from the equator and from deep convection it is reasonably well described on a day to day basis by an extended ekman balance model variability in the strength and northward extent of this flow is caused by variations in free tropospheric pressure gradients that either reinforce or oppose the pressure gradient associated with the sst gradient these free tropospheric gradients are caused by easterly waves tropical cyclones and the madden julian oscillation convergence in the boundary layer flow is often assumed to be r

vertical temperature structure associated with evaporation of stratiform precipitation in idealized wrf simulations abstracta recent study based on observations has shown that after precipitation over tropical oceans rather shallow temperature structures occur in the lower troposphere and that their magnitude de

convection and easterly wave structures observed in the eastern pacific warm pool during epic 2001 abstract during september october 2001 the east pacific investigation of climate processes in the coupled ocean atmosphere system epic 2001 intertropical convergence zone itcz field campaign focused on studies of deep convection in the warm pool region of the eastern pacific this study combines c band doppler radar sounding and surface heat flux data collected aboard the r v ronald h brown during epic to describe the kinematic and thermodynamic states of the itcz environment together with tendencies in convective structure lightning rainfall and surface heat fluxes as a function of 3 5 day easterly wave phase three easterly waves were observed at the location of the r v brown during epic 2001 wind and thermodynamic data reveal that the wave trough axes exhibited positively correlated u and winds a slight westward phase tilt with height and relatively strong weak northeasterly tropospheric shear following the trough ridge axis temperature and humidity perturbations exhibited mid to

chemical constraints and origins of four groups of gulf coast reservoir fluids pitzer s method for computing activity coefficients has been applied to reported fluid compositions in four groups of gulf coast reservoirs the mississippi and arkansas smackover formation the texas edwards group the texas frio formation and the louisiana miocene sequence the activity quotients in fluids from carbonate reservoirs imply a reaction relation between calcite and disordered dolomite in which ordering increases at higher temperatures this relationship indicates that an increasing mg ca molality ratio with decreasing temperature does not necessarily imply dolomite dissolution by an updip moving fluid instead it may reflect an approach to equilibrium between calcite and metastable dolomite activity quotients in fluids from clastic reservoirs imply a rea tion relation between chlorite illite potassium feldspar and quartz at temperatures above 100 c 212 f present fluid compositions in the smackover and the edwards appear to be related to the updip movement of louann brines from the gulf coast basin accompanied by dolomitization in particular bromide plots for the edwards fluids indicate simple dilution of louann brines with interstitial fluids similar plots for fluids from the smackover show the complicating effects of illite formation sylvite dissolution and halite recrystallization albitization may have occurred during fluid movement through clastics prior to entering the smackover and edwards present fluid compositions in the frio and miocene are apparently not related to louann brines the compositional data reflect the effects of halite dissolution the subsequent albitization of plagioclase and potassium feldspar and the dissolution of carbonates during secondary porosity formation

a hydrogeochemical approach to evaluate the occurrence and source of salinization in the shallow aquifers of the southeastern imphal valley in the indo myanmar range of northeast india the imphal valley is an intramontane basin confined within an anticlinorium of several anticlines and synclines in the disang group of rocks of tertiary age this valley of more than 2 million people is occupied by fluvio lacustrine deposits of quaternary age and is located in the central part of the indo myanmar range of northeast india the hydrogeochemical parameters of temperature ph orp tds na cl br ba b sr li 18o hco3 k mg ca no3 po4 so4 in 173 samples using ion chromatograph icp aes icp oes icp ms and 37 dugwells were studied to understand the occurrence and origin of salinization process for the first time the order of abundance of ions is identified as hco3 na cl ca mg k no3 po4 sr br b ba li so4 five hydrochemical facies na cl ca mg hco3 na hco3 ca mg hco3 cl and ca mg cl represent the types of waters the saline dominated water types na cl and na hco3 represent piedmont and the rest of the facies represent alluvial plain and flood plain groundwaters durov s diagram reveales initial and intermediate stages of groundwater evolution isotope 18o gibbs diagram and ions scatter plots suggest evaporation and crystallization processes leading to halite encrustation in the disang shales negative eh low no3 and the absence of so4 indicates reduced condition coupled with rich dissolve organic matters leading to elevation of salts in soils around piedmont where the rock type is exclusively of the disang shales trilinear plot correlation matrix and water table flow analysis suggest salinization of groundwater originates in piedmont groundwater and disseminates towards alluvial plain and flood plain along the flow path

kinematic characteristics of air flowing into and out of precipitating convection over the west pacific warm pool an airborne doppler radar survey air flowing into and out of 25 cloud systems over the west pacific warm pool was sampled by doppler radars on board two noaa wp 3d aircraft and the ncar electra aircraft during the tropical ocean global atmosphere coupled ocean atmosphere response experiment toga coare in convective cells updraught inflows and downdraught outflows tended to be positioned adjacent to each other at sharp updraught downdraught interfaces sloping at various angles and directions the updraught inflows were sometimes shallow and sometimes deep often extending well above the boundary layer downdraught outflow magnitudes were usually stronger than updraught inflows and the horizontal directions of the inflow and outflow were frequently offset from each other at angles of 90 in stratiform precipitation regions the dominant airflow features were descending mid level inflows located at the bases of anvils and often extending into the interior of the precipitation system these stratiform inflows originated at levels between 5 and 10 km and descended to about 3 km a few extended down to the surface stratiform inflows were typically strong and sandwiched between weaker stratiform outflows at upper and lower altitudes the stratiform region inflow and outflow directions were frequently offset by 90 in the horizontal the mid level inflow currents entered the stratiform regions horizontally from a direction similar to that of the large scale ambient wind the mid level stratiform inflow tended to occur in the same vertical plane as the convective downdraught outflow although the mid level stratiform inflow appeared to be slowed by horizontal pressure gradients before connecting with the convective downdraught outflow in other respects the mesoscale systems differed from a simplified two dimensional model of airflow the systems moved primarily by discrete propagation and updraughts and downdraughts tended to have orthogonal horizontal relative airflow

conceptual hydrochemical model of late pleistocene aquifers at the samario sitio grande petroleum reservoir gulf of mexico mexico carbon 14 concentrations between 0 83 and 11 79 pmc of formation water from the activo samaria sitio grande petroleum reservoir in se mexico extracted from 3500 to 4500 m b s l indicate a common infiltration event of surface water during the late pleistocene period mixing of two components meteoric water and seawater previously evaporated at the surface explain the widespread mineralization tdi 15 257 g l of na cl and na ca cl type reservoir water statistical discrimination by clustering and a heterogeneous chemical isotopic fluid composition indicate the existence of 4 different water types as part of local aquifer systems which are separated by normal and thrust faults tectonic horst and graben structures show an ambiguous individual hydraulic behaviour as permeable conduits and or as impermeable barriers causing the local limitation of aquifer extent the recent increase of water production in petroleum wells is not related to the injection of surface water but the long term extraction of oil reserves is modifying the original position and flow direction of the reservoir aquifers the rise of the initial groundwater level reflects the final stage of an exhausted petroleum reservoir with coning effects of underlying aquifer systems the flexible change towards superior production intervals could represent a feasible technique to avoid the abrupt closure of invaded production wells

hydrochemistry of the saline groundwaters of the lower mersey basin permo triassic sandstone aquifer uk saline groundwater occurs at depth in the triassic sandstones of the northern end of the cheshire basin in northwest england major and minor ion data suggest that the origin of the salinity is dissolution of evaporite deposits the salinity probably developed in an interval following the tertiary inversion of the basin which would have allowed faulted contact between the sandstones and the overlying evaporite sequence of the mercia mudstone group isotope evidence suggests the saline waters to have been considerably diluted by presumably dispersive mixing with a meteoric water recharged under cool and therefore quaternary climatic conditions comparison with other uk permo triassic basin brines suggests the merseyside waters are not unusual except in terms of the importance of exchange reactions and dilution by quaternary recharge waters these factors are due to the shallow maximum burial depth of the aquifer and the preservation of smectites and also to the geometry of the aquifer and its low permeability faults in the light of the water chemistry data it is suggested in a slight modification of the proposal of naylor et al q geol soc lond 146 685 699 1988 that the cheshire basin mineralization resulted from mixing of the relatively oxidized so4 rich evaporite brines with the reduced so4 poor metal rich barich coal measures brines which were expelled through faults from the coal measures during basin inversion some degree of oxyhydroxide stripping of the sandstones by the coal measures brines would have enhanced metal concentrations the water resulting from the mixing of brines would have been far from equilibrium and the barite and sulphide precipitation followed along the faults

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

formation waters from cambrian age strata illinois basin usa constraints on their origin and evolution abstract recently brine samples from the cambrian age mount simon formation the deepest most inaccessible sedimentary rock formation of the illinois basin and the overlying ironton galesville formation were collected as part of a major research effort evaluating the feasibility of sequestration of carbon dioxide in deep geologic formations halide and halide cation ratios especially cl br and na br ratios from groundwater samples collected during this investigation suggest that the brines of the cambrian age strata formed by the evaporation of seawater well beyond the point of halite precipitation the cl br and na br ratios the presence of mississippi valley type mvt ore mineralization in close proximity to the illinois basin and the tectonic history of the region and the illinois basin suggest that components of ore forming brines and perhaps crystalline basement brine are likely still present within the mount simon formation halide and cation halide ratio plots show that these brines have mixed with and have been diluted by subaerially evaporated seawater seawater and dilute groundwater movement of brines out of the mount simon formation and or exchange with brines of other formations is constrained by the overlying siltstone and shale rich eau claire formation a low permeability layer the most plausible interpretation of the halide and halide cation ratio data is that the brines of the cambrian age strata were introduced to the illinois basin from outside of the basin perhaps when the illinois basin was connected to the arkoma oklahoma and arkansas and black warrior basins alabama and mississippi via the reelfoot rift during cambrian and early ordovician time in addition the presence of some percentage of high nacl low cl br brines from the crystalline basement is suggested given the geochemical relationships of the halide and cation halide ratios and the tectonic history of the illinois basin finally halide and cation halide ratios determined by this investigation and regional geochemical evidence and hydrogeologic modeling by others suggest that the brines of these strata probably were affected by regional hydrothermal activity during permian time that was responsible for the mvt ore deposits of the midwestern u s thus the brines of the deepest strata of the illinois basin constitute a different more complex type of fluid than those found elsewhere in the basin halide and halide cation ratios suggest that these deep brines are dominated by residual evaporitic brine possibly originating as ore forming brines with dilution by seawater and dilute groundwater other components may include subaerially evaporated seawater and crystalline basement brines

convectively coupled kelvin waves from linear theory to global models abstractthe authors analyze composite structures of tropical convectively coupled kelvin waves cckws in terms of the theory of raymond and fuchs using radiosonde data 3d analysis and reanalysis model output and annual integrations with the ecmwf model on the full planet and on an aquaplanet precipitation anomalies are estimated using the noaa interpolated olr and trmm 3b42 datasets as well as using model olr and rainfall diagnostics derived variables from these datasets are used to examine assumptions of the theory large scale characteristics of wave phenomena are robust in all datasets and models where kelvin wave variance is large indices from the theory representing column moisture and convective inhibition are also robust the results suggest that the cckw is highly dependent on convective inhibition while column moisture does not play an important role

proposed method of hydrogeochemical exploration for salt deposits using clbr ratios eastern province kingdom of saudi arabia abstract despite the value of the salt nacl and brine used by the chemical industry geochemical prospecting techniques are not customarily employed in the search for these raw materials in this study br geochemistry is used as the basis for a proposed hydrogeochemical prospecting technique that was designed to search for shallow halite beds in the eastern province of the kingdom of saudi arabia near surface brine samples were collected at sabkhah jayb uwayyid both directly above and distant from a buried salt bed brine samples collected both directly above and offset to the north west of the salt bed had cl br ratios 8000 the regional background cl br ratio of fresh nonmarime ground water is 300 the large range in cl br ratios and the association of high cl br ratios with the buried salt body suggest that the ratio can be useful in hydrogeochemical prospecting for sibakh associated shallow salt bodies

evolution and origin of deep reservoir water at the activo luna oil field gulf of mexico mexico petroleum wells of the activo de produccion luna oil field at the mexican gulf coast are partially invaded by formation water at a production depth between 5000 and 6000 m measured 14c activities between less than 0 9 and 13 7 modern carbon reflect a homogenous late pleistocene early holocene age 40 10 ka for the regional infiltration of meteoric and marine water into the reservoir before infiltration both components were partially affected by atmospheric evaporation which explains the hypersaline composition of some formation waters very positive d18o values up to 12 5 of the formation waters are caused by strong secondary water rock interaction processes and reflect close to equilibrium conditions between the carbonate host rock and the fluids the formation of biogenic and or thermocatalytic methane in some parts of the petroleum reservoir is indicated by d13c values up to 20 4 southwest northeast directed hydraulic migration of the deep aquifer between camps sen and escuintle pijije caparroso is indicated by interference tests and pressure drawdown characteristics whereas northwest southeast trending thrust faults restrict communication toward the luna and tizon camps in the most northeastern part of the oil field on a local scale vertical zonation trends of the fluids with decreasing salinity toward upper parts of the common aquifer are related to separation processes by gravity and or by the rising of condensed vapor the migration of the fluids is mainly related to southwest northeast trending fractures and microfractures whereas northwest southeast and northeast southwest trending reverse and normal faults respectively behave irregularly as barrier or as flow conduits recently the extraction of petroleum caused an increased mobilization of the hydrodynamic aquifer system begin page 458

an air sea interaction theory for tropical cyclones part ii evolutionary study using a nonhydrostatic axisymmetric numerical model abstract in part i of this study an analytical model for a steady state tropical cyclone is constructed on the assumption that boundary layer air parcels are conditionally neutral to displacements along the angular momentum surfaces of the hurricane vortex the reversible thermodynamics implied by this assumption allows the mature storm to be thought of as a simple carnot engine acquiring heat at the high temperature ocean surface and losing heat near the low temperature tropopause although the oceanic heat source is universally recognized as the sine qua non for the mature hurricane there is also wide acceptance of conditional instability of the second kind cisk which makes no specific reference to surface heat fluxes as the formative mechanism this ambivalence is seen in that all numerical simulation studies find it essential to have transfer from the ocean surface yet all start from a conditionally unstable atmosphere the hypothesis put forward in part i based on the steady state theory is t