modelling the hydrogeochemical evolution of mine water in a decommissioned opencast coal mine abstract a method for the geochemical modelling of transient contaminant release from rehabilitated opencast coal mines including calibration against existing data is proposed the need for such a methodology is illustrated by a directive received by a decommissioned opencast coal mine in mpumalanga south africa groundwater monitoring data geochemical analyses numerical flow modelling and geochemical modelling are used to model the hydrogeochemical evolution of mine water over time models presented in this study are based on a conceptual model detailing groundwater levels and flow directions hydraulic conductivities groundwater chemistry precipitation evaporation surface water bodies and potential sources additional to this mineralogical analyses leaching tests and acid base accounting were performed to obtain a better understanding of the site geochemistry a geochemical model was constructed which was used to obtain a statistically representative mineral assemblage based on laboratory data which was calibrated against leaching test data this assemblage was simulated in field conditions as input to a numerical flow and transport model the transport of sulfate was modelled accordingly and sulfate concentrations from monitoring data were used for chemical calibration following this long term contaminant release was simulated calibration graphs from the transport model indicated concentrations within a 20 mg l error margin showing that the proposed methodology can be used to calculate contaminant concentrations in an aquifer over time within an acceptable range this approach could provide an improved estimate of the duration of the first flush which upon completion will transform decommissioned collieries into large scale reservoirs of utilisable groundwater

a study of the dynamics of the equatorial lower stratosphere by use of ultra long duration balloons 2 gravity waves in the late southern winter of 1998 centre national d etudes spatiales cnes the french space agency released six 10 m diameter superpressure balloons from a location near quito ecuador three balloons collapsed soon after launching but the remaining three drifted westward for a few weeks at altitudes between 19 and 20 km two of those balloons crossed the pacific ocean before falling above the maritime continent while the other completed a revolution around the earth and crossed the pacific for a second time before its final fall despite the small number and the relatively short duration of the flights the balloons provided a unique in situ data set for the lower equatorial stratosphere this part 1 of a two part paper describes this data set and analyzes outstanding features in the planetary scales part 2 focuses on gravity wave scale it is argued that balloon trajectories over the pacific are primarily determined by the westward drift during the easterly phase of the equatorial quasi biennial oscillation qbo and the meridional velocity field of a mixed rossby gravity yanai wave with an apparent period of 4 days and zonal wave number 4 this wave appears to have two episodes of amplification during the balloon flights it is also argued that the balloons show evidence of oscillations with periods between 2 and 4 days and of a kelvin wave with an apparent period close to 10 days and zonal wave number 1 in this way the balloon behavior provided a pictorial view of air parcel trajectory in the equatorial lower stratosphere it is stated that larger balloon campaigns can provide excellent in situ data sets for studies on the dynamics and composition of the middle atmosphere

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

the thermal evolution of chinese central tianshan and its implications insights from multi method chronometry abstract the chinese tianshan is located in the south of the central asian orogenic belt and formed during final consumption of the paleo asian ocean in the late palaeozoic in order to further elucidate the tectonic evolution of the chinese tianshan we have established the temperature time history of granitic rocks from the chinese tianshan through a multi chronological approach that includes u pb zircon 40ar 39ar biotite and k feldspar and u th he zircon and apatite dating our data show that the central tianshan experienced accelerated cooling during the late carboniferous to early permian multiple sequences of complex multiple accretionary subduction and collisional events could have induced the cooling in the tianshan orogenic belt the new 40ar 39ar and u th he data in combination with thermal history modeling results reveal that several tectonic reactivation and exhumation episodes affected the chinese central tianshan during middle triassic 245 210 ma early cretaceous 140 100 ma late oligocene early miocene 35 20 ma and late miocene 12 9 ma the middle triassic cooling dates was only found in the central tianshan strong uplift and deformation in the chinese tianshan has been limited and localized it have been concentrated in around major fault zone and the foreland thrust belt since the early cretaceous the middle triassic and early cretaceous exhumation is interpreted as distal effects of the cimmerian collisions i e the qiangtang and kunlun qaidam collision and lhasa qiangtang collision at the southern eurasian margin the cenozoic reactivation and exhumation is interpreted as a far field response to the india eurasia collision and represents the beginning of modern mountain building and denudation in the chinese tianshan

hydrogeochemical processes governing the origin transport and fate of major and trace elements from mine wastes and mineralized rock to surface waters abstract the formation of acid mine drainage from metals extraction or natural acid rock drainage and its mixing with surface waters is a complex process that depends on petrology and mineralogy structural geology geomorphology surface water hydrology hydrogeology climatology microbiology chemistry and mining and mineral processing history the concentrations of metals metalloids acidity alkalinity cl f and so 4 2 found in receiving streams rivers and lakes are affected by all of these factors and their interactions remediation of mine sites is an engineering concern but to design a remediation plan without understanding the hydrogeochemical processes of contaminant mobilization can lead to ineffective and excessively costly remediation furthermore remediation needs a goal commensurate with natural background conditions rather than water quality standards that might bear little relation to conditions of a highly mineralized terrain this paper reviews hydrogeochemical generalizations primarily from us geological survey research that enhance our understanding of the origin transport and fate of contaminants released from mined and mineralized areas mobility of potential or actual contaminants from mining and mineral processing activities depends on 1 occurrence is the mineral source of the contaminant actually present 2 abundance is the mineral present in sufficient quantity to make a difference 3 reactivity what are the energetics rates and mechanisms of sorption and mineral dissolution and precipitation relative to the flow rate of the water and 4 hydrology what are the main flow paths for contaminated water estimates of relative proportions of minerals dissolved and precipitated can be made with mass balance calculations if minerals and water compositions along a flow path are known combined with discharge these mass balance estimates quantify the actual weathering rate of pyrite mineralization in the environment and compare reasonably well with laboratory rates of pyrite oxidation except when large quantities of soluble salts and evaporated mine waters have accumulated underground quantitative mineralogy with trace element compositions can substantially improve the identification of source minerals for specific trace elements through mass balances post dissolution sorption and precipitation attenuation reactions depend on the chemical behavior of each element solution composition and ph aqueous speciation temperature and contact time with mineral surfaces for example little metal attenuation occurs in waters of low ph

global measurements of stratospheric mountain waves from space temperatures acquired by the cryogenic infrared spectrometers and telescopes for the atmosphere crista during shuttle mission sts 66 have provided measurements of stratospheric mountain waves from space large amplitude long wavelength mountain waves at heights of 15 to 30 kilometers above the southern andes mountains were observed and characterized with vigorous wave breaking inferred above 30 kilometers mountain waves also occurred throughout the stratosphere 15 to 45 kilometers over a broad mountainous region of central eurasia the global distribution of mountain wave activity accords well with predictions from a mountain wave model the findings demonstrate that satellites can provide the global data needed to improve mountain wave parameterizations and hence global climate and forecast models

quasi lagrangian superpressure balloon measurements of gravity wave momentum fluxes in the polar stratosphere of both hemispheres 1 superpressure balloons were flown in 2002 and 2005 in the winter polar vortices of both hemispheres the balloons can drift for months in the stratosphere acting as quasi lagrangian tracers of air parcel motions the meteorological datasets acquired are used to retrieve small scale internal atmospheric gravity wave parameters using wavelet techniques for the first time gravity wave momentum fluxes are estimated over wide geographical areas and the results will help constrain gravity wave parameterization schemes used in general circulation climate models the importance of mountain waves is confirmed with largest fluxes observed in the lee of greenland and the antarctic peninsula however significant momentum fluxes are also observed over the oceans showing the importance of other wave generation mechanisms

identification of hydrogeochemical processes and pollution sources of groundwater resources in the marand plain northwest of iran the main aims of the present study are to identify the major factors affecting hydrogeochemistry of groundwater resources in the marand plain nw iran and to evaluate the potential sources of major and trace elements using multivariate statistical analysis such as hierarchical clustering analysis hca and factor analysis fa to achieve these goals groundwater samples were collected in three sampling periods in september 2013 may 2014 and september 2014 and analyzed with regard to ions e g ca2 mg2 na and k hco3 so4 2 cl f and no3 and trace metals e g cr pb cd mn fe al and as the piper diagrams show that the majority of samples belong to na cl water type and are followed by ca hco3 and mixed ca na hco3 cross plots show that weathering and dissolution of different rocks and minerals ion exchange reverse ion exchange and anthropogenic activities especially agricultural activities influence the hydrogeochemistry of the study area the results of the fa demonstrate that 6 factors with 81 7 of total variance are effective in the overall hydrogeochemistry which are attributed to geogenic and anthropogenic impacts the hca categorizes the samples into two clusters samples of cluster c1 which appear to have higher values of some trace metals like pb and as are spatially located at the eastern and central parts of the plain while samples of cluster c2 which express the salinization of the groundwater are situated mainly westward with few local exceptions

observations and simulations of a large amplitude mountain wave breaking over the antarctic peninsula 1 a case study of a large amplitude orographic gravity wave occurring over the antarctic peninsula is presented based on observations from the vorcore balloon campaign and on mesoscale numerical simulations the vorcore campaign september 2005 to february 2006 consisted in the flight of 27 superpressure balloons in the core of the southern hemisphere stratospheric polar vortex at altitudes of 16 19 km from september 2005 to february 2006 on 7 october 2005 one of the balloons exploded as it was flying above the antarctic peninsula the observations collected by another balloon that was flying during the same time period above the peninsula suggest the presence of a very intense gravity wave peak to peak amplitude of the order of 25 30 m s 1 in zonal and meridional velocity disturbances the wave packet is likely undersampled in the balloon observations because of its high intrinsic frequency but the balloon data set is complemented with high resolution numerical simulations carried out with the weather research and forecast model the simulations are validated by comparison with the balloon measurements and show that the wave was breaking in the lower stratosphere at the time and height where the balloon exploded the simulations highlight several consequences of the mountain wave on the stratosphere forcing of the mean flow generation of secondary inertia gravity waves and turbulence and mixing in particular the momentum fluxes are calculated and are found to compare well with the estimates from balloon measurements the large values found are likely extreme values which raises the issue of their representativity to discuss this the balloon measurements are used in conjunction with operational analyses to estimate the frequency of such large amplitude gravity waves i e to provide an estimate of their intermittency

estimation of gravity wave momentum flux and phase speeds from quasi lagrangian stratospheric balloon flights part i theory and simulations a methodology for estimating gravity wave characteristics from quasi lagrangian observations provided by long duration superpressure balloon flights in the stratosphere is reviewed wavelet analysis techniques are used to detect gravity wave packets in observations of pressure temperature and horizontal velocity an emphasis is put on the estimation of gravity wave momentum fluxes and intrinsic phase speeds which are generally poorly known on global scales in the atmosphere the methodology is validated using monte carlo simulations of time series that mimic the balloon measurements including the uncertainties associated with each of the meteorological parameters while the azimuths of the wave propagation direction are accurately retrieved the momentum fluxes are generally slightly underestimated especially when wave packets overlap in the time frequency domain or for short period waves a proxy is derived to estimate by how much momentum fluxes are reduced by the analysis retrievals of intrinsic phase speeds are less accurate especially for low phase speed waves a companion paper part ii implements the methodology to observations gathered during the vorcore campaign that took place in antarctica between september 2005 and february 2006

estimation of gravity wave momentum flux and phase speeds from quasi lagrangian stratospheric balloon flights part ii results from the vorcore campaign in antarctica the stratospheric gravity wave field in the southern hemisphere is investigated by analyzing observations collected by 27 long duration balloons that flew between september 2005 and february 2006 over antarctica and the southern ocean the analysis is based on the methods introduced by boccara et al in a companion paper special attention is given to deriving information useful to gravity wave drag parameterizations employed in atmospheric general circulation models the balloon dataset is used to map the geographic variability of gravity wave momentum fluxes in the lower stratosphere this flux distribution is found to be very heterogeneous with the largest time averaged value 28 mpa observed above the antarctic peninsula this value exceeds by a factor of 10 the overall mean momentum flux measured during the balloon campaign zonal momentum fluxes were predominantly westward whereas meridional momentum fluxes were equally northward and southward a local enhancement of southward flux is nevertheless observed above adelie land and is attributed to waves generated by katabatic winds for which the signature is otherwise rather small in the balloon observations when zonal averages are performed oceanic momentum fluxes are found to be of similar magnitude to continental values 2 5 3 mpa stressing the importance of nonorographic gravity waves over oceans last gravity wave intermittency is investigated mountain waves appear to be significantly more sporadic than waves observed above the ocean

evaluation of momentum and sensible heat fluxes in constant density coordinates application to superpressure balloon data during the vorcore campaign 1 expressions for momentum and heat fluxes using density as the vertical coordinate are derived these are applied in the evaluation of fluxes using data from super pressure balloons drifting on constant density surfaces in the antarctic lower stratosphere during the vorcore campaign september 2005 to february 2006 we focus on the core months of october and november vertical fluxes of zonal and meridional momentum are calculated using wind pressure and height data and the vertical flux of sensible heat is calculated using temperature and height data calculations were performed in three band passes covering 1 13 h we find that the largest fluxes are in the vicinity of the antarctic peninsula in october the fluxes in the low period band pass 1 5 h account for the main part of the total flux of zonal momentum consistent with topographically forced waves during november the vertical fluxes of zonal momentum are found mainly in longer period band passes consistent with weaker winds the peak campaign averaged flux of zonal momentum in the vicinity of the antarctic peninsula is 30 mpa these values are 60 larger over the peninsula than those inferred by other authors the flux of zonal momentum provides a zonal body force of 5 m s 1 day 1 assuming a saturated spectrum we infer downward sensible heat fluxes of 3 w m 2 the corresponding cooling rates assuming a saturated spectrum are 0 6 k day 1 a significant fraction of the net radiative imbalance in the springtime antarctic lower stratosphere

acoustic waves generated by gusty flow over hilly terrain 1 we examine the generation of acoustic waves by gusty flow over hilly terrain we use simple theoretical models of the interaction between terrain and eddies and a linear model of acoustic gravity wave propagation the calculations presented here suggest that over a dense array of geographically extensive sources orographically generated vertically propagating acoustic waves can be a significant cause of thermospheric heating this heating may account in good part for the thermospheric hot spot near the andes reported by meriwether et al 1996 1997

control of coal facies to adsorption desorption divergence of coals a case from the xiqu drainage area gujiao cbm block north china abstract adsorption and desorption of coal to methane are substantially related to coal facies referring to the production potential of a coalbed methane cbm well based on analyses of the stratified channel samples from coal seams no 2 no 4 and no 9 in the xiqu drainage area gujiao cbm block north china the relationship between coal facies and adsorption desorption behaviors was first proposed and discussed using the coal facies diagrams suggested by previous investigators four types of coal facies were distinguished in the coal seams including the upper delta plain wet forest swamp i the lower delta plain fen ii the lower delta plain marsh iii and the back barrier low moor iv the upper delta plain wet forest swamp occurred dominantly developing at the bottom and top of all the coal seams both the ash yield and groundwater index gwi tend to increase from coal facies i to iv whereas the volatile compounds fixed carbon organic sulfur total sulfur micropore volume and specific surface area tissue preservation index tpi and vegetation index vi decreased which indicates changes in the vegetation types water supplements and disturbance acid base properties and redox conditions in the paleomires paleomire evolution accompanied the rise and drop of the sea level with a transgression or regression process that could be represented by the coal facies sequence coal seams no 2 no 4 and no 9 were discriminated into two three and two evolving stages respectively and these stages were characterized by complete cycles except stage 4 i from the lower delta plain marsh mudstone partings in the coal seams deposited during the highest sea level collectively paleomire environments especially the variation of vegetation types and mire water condition result in adsorption and desorption divergences among different coal facies arborescent plants decrease from coal facies i to iv as the hydrodynamic intensity increases leading to corresponding changes in botanical tissue preservation medium oxidizability mineral content and ultimately adsorption and desorption behaviors in view of the gas content and desorption capacity of the coal layers in the same coal seam the layers from the upper delta plain wet forest swamp may have the best potential for cbm drainage followed by those from the lower delta plain fen and marsh while those from the back barrier low moor may have the worst potential

lidar observations of a breaking mountain wave associated with extreme turbulence observations from a doppler lidar which are enhanced by stratospheric aerosols from mount pinatubo s eruption provide unique measurements of mountain waves over the rocky mountains including nearly instantaneous observations of wave breaking in the lower stratosphere the wave breaking is revealed by a flow reversal aloft that marks a localized critical layer created when the wave amplitude was great enough to cause overturning the altitude spatial scale and duration of this wave induced critical layer are documented the mountain waves led to turbulence affecting commercial aircraft including one accident in which a cargo jet lost an engine and part of a wing in extreme turbulence at the same time the lidar was making observations nearby although earlier observations of mountain wave drag assumed wave stationarity over 3 5 h significant changes over less than 2 h are documented here such nonstationarity could contribute to discrepancies remaining between observations and simulations of mountain wave drag

large amplitude mountain wave breaking over greenland abstract a large amplitude mountain wave generated by strong southwesterly flow over southern greenland was observed during the fronts and atlantic storm track experiment fastex on 29 january 1997 by the noaa g iv research aircraft dropwindsondes deployed every 50 km and flight level data depict a vertically propagating large amplitude wave with deep convectively unstable layers potential temperature perturbations of 25 k that deformed the tropopause and lower stratosphere and a vertical velocity maximum of nearly 10 m s 1 in the stratosphere the wave breaking was associated with a large vertical flux of horizontal momentum and dominated by quasi isotropic turbulence the coupled ocean atmosphere mesoscale prediction system coamps nonhydrostatic model with four nested grid meshes with a minimum resolution of 1 7 km accurately simulates the amplitude location and timing of the mountain wave and turbulent breakdown finescale low velocity plumes that resemble wakelike structures emanate from highl

gravity wave breaking over the central alps role of complex terrain abstract the characteristics of gravity waves excited by the complex terrain of the central alps during the intensive observational period iop 8 of the mesoscale alpine programme map is studied through the analysis of aircraft in situ measurements gps dropsondes radiosondes airborne lidar data and numerical simulations mountain wave breaking occurred over the central alps on 21 october 1999 associated with wind shear wind turning and a critical level with richardson number less than unity just above the flight level 5 7 km of the research aircraft ncar electra the electra flew two repeated transverses across the otztaler alpen during which localized turbulence was sampled the observed maximum vertical motion was 9 m s 1 corresponding to a turbulent kinetic energy tke maximum of 10 5 m2 s 2 spectrum analysis indicates an inertia subrange up to 5 km wavelength and multiple energy containing spikes corresponding to a wide range of wavelengths manual analysis of gps dropsonde data indic

observation and analysis of a large amplitude mountain wave event over the antarctic peninsula 1 we use measurements from the atmospheric infrared sounder airs on the aqua satellite to observe the 3 dimensional structure of a gravity wave event over the antarctic peninsula and determine the horizontal and vertical wavelengths propagation direction and temperature amplitude and from these we estimate wave momentum flux using theoretical knowledge of the weighting functions and radiative transfer for airs radiance measurements at temperature sensitive channels in the infrared we derive a method of estimating wave temperature amplitude directly from the radiance measurements comparison of the radiance based temperature amplitudes to the temperature amplitude in airs retrieved temperature fields shows close agreement because the radiances have 3 times better horizontal resolution than the retrievals our analysis suggests we can routinely observe important geophysical properties of waves with horizontal wavelengths as short as 80 km using airs radiances we further analyze a nearly identical wave event appearing in the european centre for medium range forecasts ecmwf temperature and wind fields from both assimilation and forecast data analysis of the ecmwf data and nearby radiosonde wind profiles allows the interpretation as a mountain wave event forced by flow over the topography of the antarctic peninsula

the behavior of wave 2 in the southern hemisphere stratosphere during late winter and early spring abstract a detailed analysis is presented of the behavior of the zonal wavenumber 2 component of the flow wave 2 for july through october in the southern hemisphere stratosphere wave 2 in the stratosphere is characterized by a broad meridional structure peaking between 55 and 65 s and regular eastward propagation with periods ranging from 5 to 40 days maximum geopotential height amplitudes for a year range from approximately 600 to 1000 m examination of vertical structure suggests that during episodes of largest growth wave 2 propagates upward from the upper troposphere regular eastward propagation is however evident only within the stratosphere there are also episodes of wave 2 growth that do not appear connected with the troposphere in general the wave 2 amplitude is not as large in these cases there are several years when wave 1 and wave 2 amplitudes are strongly anticorrelated in time during september and october there are also years with strong positive correlation during august and

determining the factors controlling the chemical composition of groundwater using multivariate statistics and geochemical methods in the xiqu coal mine north china studying the hydrogeochemical processes that control groundwater quality in different aquifers helps to identify the sources of inrush water into coal mines in this paper 65 mine water samples were collected from xiqu coal mine during 2016 and 2017 to determine the hydrogeochemical processes and controlling factors of mine water using hydrochemical methods and multivariate statistical analysis the mine water is acidic to alkaline in nature the dominant anions in the mine water are so42 and hco3 and cations were dominated by ca2 na and mg2 the dominant hydrochemical facies of groundwater were so4 na ca and so4 ca mg water types based on multivariate statistical analysis four principal components and two clusters were obtained concentrations of so42 showed significant positive correlations with ca2 mg2 fe2 and fe3 and strong negative correlations with hco3 and ph the mine water chemistry was dominated by the oxidation of iron bearing sulfide minerals cation exchange and the dissolution of silicate carbonate and sulfate minerals in addition human activities such as agriculture are also likely to have influences groundwater chemistry at the mine site

small scale gravity waves in the upper mesosphere and lower thermosphere generated by deep tropical convection a time dependent nonlinear fully compressible axisymmetric plane numerical model is used to simulate the generation of small scale gravity waves in the upper mesosphere and lower thermosphere by intense deep convection in the troposphere the simulations show that major convective storms in the tropics excite a broad spectrum of upper mesosphere lower thermosphere gravity waves above the storm centers the wave field includes a component that is guided in a thermal duct in the lower thermosphere and propagates horizontally outward from above the storm storms excite oscillations over the source which are initially confined to a stratospheric duct but leak into the thermospheric duct over time generating a long train of small scale ducted waves this ringing phenomenon persists for several hours after the storm has ended the ducted disturbances may propagate large distances from the source and explain observations of a strong summertime anisotropy favoring southward propagation of small scale waves observed in the airglow over adelaide more than 2000 km to the south of the storm events