oxygen isotope and geochemical variations in the missouri river oxygen isotope ratios in streamflow of the missouri river basin vary geographically due to differences in source precipitation and the integration of waters from upstream regions average 18o values in the missouri river main stem systematically increase from less than 17 in the headwaters to about 9 in the lower basin seasonal variations at a given location result from fluctuations in meteoric precipitation residence time in reservoirs and groundwater systems evaporation and snowmelt average water chemistry values are successfully predicted for the upstream stations of two reaches on the lower missouri river based on changes in discharge along each reach and water quality measurements collected at the downstream stations source regions for some dissolved ions found in the lower missouri river are also identified sodium and sulfate originate predominantly from the basin above sioux city iowa while nitrate is largely derived from agricultural regions below sioux city

migration of chlorinated hydrocarbon solvents through coventry sandstone rock columns the migration in the coventry sandstone aquifer system of aqueous solutions of various chlorinated hydrocarbon solvents chss 1 1 1 trichloroethane tca trichloroethylene tce and tetrachloroethylene tece was studied by means of percolation experiments with undisturbed rock cores the retardation factor rf was very low always less than 2 for tca less than 3 for tce and less than 5 for tece the rf varied slightly according to the nature of the solid sample but could not be related to the solid organic carbon content the solvent adsorption was always almost completely reversible and little affected by the percolation flow rate 0 08 0 56 m day 1 the chs breakthrough curves were typical of non equilibrium processes caused by sorption by the solids and possibly by diffusion between mobile and immobile water the rf values obtained experimentally were much lower than those calculated from batch adsorption studies showing that percolation experiments are necessary to evaluate the filtering properties of consolidated rocks these results indicate that in the coventry sandstone aquifer relatively high vertical and especially lateral hydraulic conductivities two carbon chs aqueous solutes should migrate readily with water with very little retardation

postscript summary of the coventry groundwater investigation and implications for the future abstract the broader implications of the coventry groundwater investigation are discussed in this postscript the complex interbedded sandstone and mudstone sequence under coventry is seriously polluted by chlorinated hydrocarbon solvents investigations in such terrain will require much greater expenditure than was available for this project if they are to describe the distribution and movement of pollutants in enough detail to evaluate quantitatively options for aquifer clean up it is not realistic to consider clean up of coventry s groundwater at the present time because of the lack of detailed knowledge it is probable at least for the present that clean up is not feasible because of hydrogeological constraints arising from the extreme variability of permeability in the system and an absence of operational techniques for clean up stronger more pro active protection of groundwater is needed a major recommendation for future investigations is a procedure to avoid open boreholes which can allow pollution to penetrate deeper into the aquifer and may confuse the results of sampling

geochemical characteristics of fluoride in groundwater of gimcheon korea lithogenic and agricultural origins the occurrence of fluoride in groundwaters can be influenced by many factors in korea the fluoride rich groundwaters are normally associated with rock types especially granite and gneiss in gimcheon high fluoride groundwaters up to a maximum of 2 15 mg l were observed with bimodal distribution of concentrations the groundwater in this area showed relatively high concentrations of anthropogenic chemicals such as nitrate chloride and sulfate statistical analysis showed that fluoride is positively correlated with ph alkalinity sodium and lithium indicating that the interaction with granite is the main cause enriching its concentration in gimcheon 18o data of groundwater showed a negative correlation with nitrate and can be used as an indicator of groundwater age the four samples of fluoride rich groundwater were plotted in the light d and 18o region showing that they were the result of long water rock reaction however other groundwater with a low fluoride concentration was evenly distributed throughout all d and 18o ranges and did not show a statistically significant correlation with nitrate indicating possible mixing with another source of fluoride considering the influence from the surface on the geochemical characteristics of groundwater in this area anthropogenic sources including phosphate fertilizer containing fluoride and pesticides may also have partly contributed to the concentrations of fluoride in the low fluoride groundwater the scattered distribution of fluoride rich groundwater and the significant correlation with lithium suggest that pegmatite is the main rock type increasing fluoride concentration in this area

the fluvial geochemistry of the rivers of eastern siberia i tributaries of the lena river draining the sedimentary platform of the siberian craton abstract the response of continental weathering rates to changing climate and atmospheric pco 2 is of considerable importance both to the interpretation of the geological sedimentary record and to predictions of the effects of future anthropogenic influences while comprehensive work on the controlling mechanisms of contemporary chemical and mechanical weathering has been carried out in the tropics and to a lesser extent in the strongly perturbed northern temperate latitudes very little is known about the peri glacial environments in the subarctic and arctic thus the effects of climate essentially temperature and runoff on the rates of atmospheric co 2 consumption by weathering are not well quantified at this climatic extreme to remedy this lack a comprehensive survey has been carried out of the geochemistry of the large rivers of eastern siberia the lena yana indigirka kolyma anadyr and numerous lesser streams which drain a pristine high latitude region that has not experienced the pervasive effects of glaciation and subsequent anthropogenic impacts common to western eurasia and north america the scale of the terrain sampled in terms of area is comparable to that of the continental united states or the amazon orinoco and includes a similarly diverse range of geologic and climatic environments in this paper the chemical fluxes from the western region the very large ancient and geologically stable sedimentary basin precambrian to quaternary of the siberian platform will be presented and compared to published results from analogous terrains in the tropical basins of china while the range in the chemical signatures of the various tributaries included here 60 sampled is large this mainly reflects lithology rather than the weathering environment the areal chemical fluxes are comparable to those of the chinese rivers being dominated by the dissolution of carbonates and evaporites the net consumption of atmospheric co 2 by aluminosilicate weathering is minor as it is in the tropical basins it is much smaller than in active orogenic belts in similar latitudes e g the fraser and yukon but comparable to those of the mackenzie tributaries that drain the eastern slope of the rockies lithology exerts the dominant influence in determining the weathering yield from sedimentary terrains and for a largely carbonate evaporite terrain climate does not have a direct effect

investigation of a solvent polluted industrial site on a deep sandstone mudstone sequence in the uk part 2 contaminant sources distributions transport and retardation abstract a single industrial site has been investigated in detail to gain information on sources and movement of chlorinated hydrocarbon solvent chs pollutants in groundwater under the industrialized city of conventry in the uk a soil gas survey identified the most polluted area of the site where two types of investigation borehole were drilled open boreholes lined with plain and slotted casing and a single dedicated borehole incorporating gas samplers and gas driven water samplers specially designed sampling techniques using pumps and packers were employed to determine vertical pollution profiles in the open boreholes core material was collected for sorption and diffusion experiments an assessment of field investigation procedures suggests that soil gas sampling is a useful method for reconnaissance surveying of pollution by volatile organic compounds but the results reflect only shallow pollution in the vertical profile open boreholes were found not to be satisfactory for accurate groundwater profile sampling and dedicated boreholes are recommended for such studies many uncertainties are involved in such a study of solvent pollution owing to the limited number of boreholes drilled and the complex spatial and temporal variations of pollutants despite the limitations of the investigation several useful conclusions are drawn concerning sources and movement of solvent pollution the main pollution source at the site is identified as the solvent storage tanks and pollution has resulted from poor use practices vertical pollution profiles indicate that the downward migration of 1 1 1 trichloroethane is following that of trichloroethene reflecting their history of use on the site the overall quality of groundwater abstracted in the system is set to deteriorate as high pollution loads presently at shallow levels in the system penetrate deeper little attenuated by sorption or degradation diffusion of pollutants between mobile fissure and immobile pore waters will result in poor quality groundwater under this site for the foreseeable future this trend is expected to be reflected throughout the urban area as a whole with most groundwaters falling below drinking water standards for chss

water geochemistry controlled by carbonate dissolution a study of the river waters draining karst dominated terrain guizhou province china concentrations of major ions and sr and sr isotopic compositions of two major river systems wujiang river and yuanjiang river in karst dominated regions and during winter were measured the rivers and their tributaries have high total dissolved solid concentrations with tz ranging from 2 1 to 6 3 meq l which are significantly higher than that of the global river average calcium and hco3 followed by mg2 and so42 dominate the chemical composition of major ions in the river waters both na k and cl si account for 5 10 of the cations and anions respectively the waters of the wujiang river have high sr2 concentrations and lower 87sr 86sr ratios 0 7077 0 7110 while those of the qingshuijiang river one of two major tributaries of the yuanjiang river system show higher sr isotopic ratios 0 7090 0 7145 and low sr concentrations the lithology and geography of the river basins largely control the chemical and isotopic compositions of these rivers analyses of the stoichiometry of the river waters show that the water chemistry is controlled by carbonate dissolution by both carbonic and sulfuric acid especially of the wujiang river and suggest an origin of sulfate mainly from atmospheric input because of coal combustion and or oxidation of sulfide minerals in the catchments we identify three main weathering sources limestone dolomite and silicates chemical and sr isotopic composition of wujiang river waters are characterized mainly by limestone weathering while those of the qingshuijiang river waters mainly by dolomite and silicate weathering chemical weathering rates of carbonate and silicate are estimated and the results indicate that the chemical weathering rates of carbonate in the catchments are remarkably high significantly higher than most large rivers it is considered that presence of sulfuric acid in the rock weathering overuse of land and deterioration of vegetation are most likely the key factors responsible for the high weathering rates of carbonate in the catchments

empirical relationships between elevation and the stable isotope composition of precipitation and surface waters considerations for studies of paleoelevation change a compilation of 68 studies from throughout many of the world s mountain belts reveals an empirically consistent and linear relationship between change in elevation and change in the isotopic composition of precipitation along altitudinal transects the isotopic composition of precipitation decreases linearly with increasing elevation in most regions of the world except in the himalayas and at elevations 5000 m there are no significant differences in isotopic lapse rates from most regions of the world 0 28 permil 100 m except at the extreme latitudes where isotopic lapse rates are higher given information on past changes in the isotopic composition of precipitation preserved in pedogenic or authigenic minerals this global isotopic lapse rate can be used to place numerical constraints on the topo graphic development of some ancient mountain belts or plateaus there are many complicating factors that can confound interpretation of paleoel evation change based on stable isotopes and many of these are unique to specific mountain belts or time periods relevant to all stable isotope based paleoelevation change studies is the temperature dependent isotope fractionation between a pedo genic or authigenic mineral and the water from which it forms in cases where isotopic proxy minerals are sampled from localities where temperature will change simulta neously with elevation change the apparent change in the isotopic composition of precipitation may be dampened by several permil this suggests that samples taken from the rainshadow side of an emerging orographic barrier may be more likely to preserve isotopic changes resulting from mountain uplift than samples taken from atop a rising mountain range or plateau

recent earth oblateness variations unraveling climate and postglacial rebound effects earth9s dynamic oblateness j2 has been decreasing due to postglacial rebound pgr however j2 began to increase in 1997 indicating a pronounced global scale mass redistribution within earth9s system we have determined that the observed increases in j2 are caused primarily by a recent surge in subpolar glacial melting and by mass shifts in the southern pacific and indian oceans when these effects are removed the residual trend in j2 2 9 x 10 11 year 1 becomes consistent with previous estimates of pgr from satellite and eclipse data the climatic significance of these rapid shifts in glacial and oceanic mass however remains to be investigated

natural and anthropogenic so4 sources in the arno river catchment northern tuscany italy a chemical and isotopic reconnaissance abstract the 34 s isotope signature of aqueous so 4 2 in the main river arno and principal tributaries was investigated along with major ion chemistry in order to check the pollution effects in the water network of a heavily industrialized and densely urbanized catchment extending in tuscany over an area of 8228 km 2 from the apennine ridge to the tyrrhenian sea major towns include florence and pisa analyses are presented for 29 water samples from the arno river and 36 water samples from the tributaries all collected in 1996 1997 during low flow hydrologic conditions samples from the arno are distributed from source to mouth and those from tributaries upstream from the confluence points the arno river solutes consist mainly of ca 2 and hco 3 but the proportions of na cl and so 4 2 increase downstream in keeping with the basically anthropogenic origin of the latter the 34 s so 4 2 signature also increases downstream with the most depleted values in the source zone the seawater ingression into the river is documented by distinctly higher chemical and isotopic parameters at about 13 km from the mouth in general the tributaries behave similarly to the arno for both their chemical and isotopic compositions with increasing 34 s na cl and so 4 2 downstream the 34 s of so 4 2 in natural inputs is estimated to range approximately between 15 and 4 from oxidation of pyrite disseminated in country rocks and between 15 and 23 from dissolution of evaporites whereas the 34 s of anthropogenic so 4 2 should be variable within the range 1 8

hydrological and isotopic characterization of river water groundwater and groundwater recharge in the heihe river basin northwestern china we used hydrochemistry and environmental isotope data 18o d tritium and 14c to investigate the characteristics of river water groundwater and groundwater recharge in china s heihe river basin the river water and groundwater could be characterized as ca2 mg2 hco3 so42 and na mg2 so42 cl types respectively hydrogeochemical modelling using phreeqc software revealed that the main hydrogeochemical processes are dissolution except for gypsum and anhydrite along groundwater flow paths from the upper to middle heihe reaches towards the lower reaches dolomite and calcite tend to precipitate the isotopic data for most of the river water and groundwater lie on the global meteoric water line gmwl or between the gmwl and the meteoric water line in northwestern china indicating weak evaporation no direct relationship existed between recharge and discharge of groundwater in the middle and lower reaches based on the isotope ratios d excess and 14c values on the basis of tritium in precipitation and by adopting an exponential piston flow model we evaluated the mean residence time of shallow groundwater with high tritium activities which was around 50 years a furthermore based on the several popular models it is calculated that the deep groundwaters in piedmont alluvial fan zone of the middle reaches and in southern part of the lower reaches are modern water whereas the deep groundwaters in the edge of the middle reaches and around juyan lake in the lower reaches of heihe river basin are old water copyright 2010 john wiley sons ltd

hydrogeology of the coventry region uk an urbanized multilayer dual porosity aquifer system abstract the coventry groundwater investigation has researched the sources and movement of chlorinated hydrocarbon solvents in the groundwater system underlying the coventry region the hydrogeological scene is set in this paper as a basis for the other aspects of the investigation which are reported in the other papers in this volume the deep intercalcated sandstones and mudstones of the permo carboniferous which underly the study area behave as a multilayer aquifer although individual aquifer units are not regionally extensive the sandstone units are fractured and behave as dual porosity aquifers with rapid tracer movement in fractures and diffusion into the low permeability but porous matrix the water balance of the groundwater system has changed from natural conditions because of man s influence although direct recharge has been reduced by the impermeable surfaces of roads and towns substantial extra recharge arises in the urban areas from leaking water mains

major ion chemistry of the ganga brahmaputra river system weathering processes and fluxes to the bay of bengal the ganga brahmaputra one of the world s largest river systems is first in terms of sediment transport and fourth in terms of water discharge a detailed and systematic study of the major ion chemistry of these rivers and their tributaries as well as the clay mineral composition of the bed sediments has been conducted the chemistry of the highland rivers upper reaches of the ganga the yamuna the brahmaputra the gandak and the ghaghra are all dominated by carbonate weathering ca mg and hco3 account for about 80 of the cations and anions in the lowland rivers the chambal the betwa and the ken hco3 excess over ca mg and a relatively high contribution of na k to the total cations indicate that silicate weathering and or contributions from alkaline saline soils and groundwaters could be important sources of major ions to these waters the chemistry of the ganga and the yamuna in the lower reaches is by and large dictated by the chemistry of their tributaries and their mixing proportions illite is the dominant clay mineral about 80 in the bedload sediments of the highland rivers kaolinite and chlorite together constitute the remaining 20 of the clays in the chambal betwa and ken smectite accounts for about 80 of the clays this difference in the clay mineral composition of the bed sediments is a reflection of the differences in the geology of their drainage basins the highland rivers weather acidic rocks whereas the others flow initially through basic effusives the ganga brahmaputra river system transports about 130 million tons of dissolved salts to the bay of bengal which is nearly 3 of the global river flux to the oceans the chemical denudation rates for the ganga and the brahmaputra basins are about 72 and 105 tons km yr 1 respectively which are factors of 2 to 3 higher than the global average the high denudation rate particularly in the brahmaputra is attributable to high relief and heavy rainfall

factors controlling carbon isotope ratios of dissolved inorganic carbon in two major tributaries of the han river korea understanding the carbon cycle of the han river system in korea is of prime interest in managing and preserving this valuable water resource for more than 20 million residents in the area as a part of a comprehensive carbon cycling study for the han river system this report focuses on the carbon isotope compositions of dissolved inorganic carbon dic in its two major tributaries the north and the south han rivers the major difference in carbonate chemistry of the tributaries originates primarily from the lithology of the catchment areas the south han river draining a carbonate dominant terrain has much higher alkalinities and dic concentrations whereas the lower concentrations in the north han river indicate little influence of carbonate weathering likewise 13cdic values in the south han river indicate that the dic input from the carbonate rocks is important in controlling carbon isotope ratios of dic for the north han river the oxidation of organic material influences the amount of riverine dic and 13cdic values to a greater extent overall remarkable seasonal and spatial variations of river chemistry and carbon isotope compositions of dic reflect the variability in geo hydrologic characteristics in the water regime and in metabolic activities in the river water and or the drainage areas copyright 2006 john wiley sons ltd

relation between sea level and bottom pressure and the vertical dependence of oceanic variability 1 the relation between large scale sea level and bottom pressure variability is studied using long 50 yr simulations of a general circulation model under realistic forcing admittance and coherence analyses are used to characterize the bottom pressure and sea level relationship as a function of period horizontal spatial scale and location at the model grid scale 1 bottom pressure is found to be essentially equivalent to sea level at periods 60 and in shallow depths 200 m elsewhere bottom pressure and sea level fields can differ significantly results indicate an increase of the importance of baroclinic signals with decreasing latitude and spatial scale with significant baroclinic signals at intra seasonal and longer periods present in many subtropical and mid latitude regions variability is clearly baroclinic at inter annual periods regardless of location and spatial scale results have broad implications for the interpretation and processing of both satellite altimetry and gravity data and for their assimilation into numerical models

investigation of a solvent polluted industrial site on a deep sandstone mudstone sequence in the uk part 1 site description and groundwater flow abstract the sources and subsurface movement of chlorinated hydrocarbon solvents have been investigated at an industrial site as part of a wider study of groundwater pollution by these solvents in the area of coventry uk this paper presents a description of the site and groundwater flow as a prelude to a second paper describing the distribution transport and fate of pollutants both open boreholes and a single borehole incorporating a multilevel sampler were constructed and pumping and tracer tests performed the latter borehole was the most successful in defining hydraulic heads for individual aquifer units the cyclic pumping of the production borehole was analysed using a computer model to gain hydraulic data for aquifer and aquitard units the tracer test defined qualitatively the role played by matrix diffusion in solute transport within the dual porosity aquifer it is concluded that horizontal groundwater flow is dominant along fissured moderately permeable sandstone layers the low permeabilities of mudstone layers maintain high vertical hydraulic gradients sorption of contaminants on to the aquifer matrix is likely to be low owing to a low fraction of organic carbon however matrix diffusion will serve to attenuate peak concentrations of pollutants and stretch pollution pulses in time

a review of central asian glaciochemical data the glaciers of central asia provide suitable locations from which to recover continuous high resolution glaciochemical records on a continental scale although the glaciochemical investigations undertaken to date in central asia are few in number and limited in terms of spatial coverage and length of record some preliminary observations can be made concerning regional and seasonal trends in snow chemistry in this region the sodium chloride ratio for most snow samples collected in central asia approaches the ratio found in sea water 0 86 in leq kg i reflecting a marine source for these constituents sodium and chloride concentrations are on average 3 10 times higher in the himalayas than in the karakoram demonstrating the greater influence of monsoonal sources of moisture in the himalayas very high sodium concentrations from khel khod glacier probably reflect a local crustal source from surrounding ice free areas low nitrate concentrations were found in snow collected from the southern margin of the himalayas and high concentrations in snow deposited on the north margin of the himalayas this strong regional trend in the spatial distribution of nitrate suggests the influx of continental aerosols rich in nitrate originating from the arid regions of central asia high calcium concentrations measured in snow from mount everest and the north west corner of china are also indicative of dust derived from the arid regions of central asia very high sulfate concentrations found in snow from the tien shan and the bogda shan most likely reflect local anthropogenic sources the altitude effect on isotopic composition is not apparent from snow samples collected in central asia understanding the processes which control the chemical content of snow the local to regiona l scale complexities

time variability of the earth s gravity field hydrological and oceanic effects and their possible detection using grace the grace satellite mission scheduled for launch in 2001 is designed to map out the earth s gravity field to high accuracy every 2 4 weeks over a nominal lifetime of 5 years changes in the gravity field are caused by the redistribution of mass within the earth and on or above its surface grace will thus be able to constrain processes that involve mass redistribution in this paper we use output from hydrological oceanographic and atmospheric models to estimate the variability in the gravity field i e in the geoid due to those sources we develop a method for constructing surface mass estimates from the grace gravity coefficients we show the results of simulations where we use synthetic grace gravity data constructed by combining estimated geophysical signals and simulated grace measurement errors to attempt to recover hydrological and oceanographic signals we show that grace may be able to recover changes in continental water storage and in seafloor pressure at scales of a few hundred kilometers and larger and at timescales of a few weeks and longer with accuracies approaching 2 mm in water thickness over land and 0 1 mbar or better in seafloor pressure

low frequency variations in global mean sea level 1950 2000 1 low frequency variability in global mean sea level gmsl is studied for the period 1950 2000 by interpolating sparse tide gauge data to a global grid using empirical orthogonal functions eofs of sea level variability determined from topex poseidon t p altimeter data results are based on data with long term trends removed the fact that the results do not have secular trends is an artifact of the analysis and should not be interpreted as an indication that sea level is not rising the eof reconstruction technique is discussed and the resulting gmsl time series is compared to gmsl time series from geosat and t p altimetry and proxy gmsl time series estimated from global sea surface temperature data the error assessment suggests the accuracy of the gmsl time series reconstructed from the tide gauge data is 2 4 mm rms for a 1 year running mean smoothing and about 1 mm for a 5 year running mean smoothing several el nino la nina events are evident in the gmsl as well as significant low frequency variability at a 10 12 year period gmsl appears to have been generally lower than normal in the late 1960s throughout the 1970s and in the 1980s gmsl appears to have been generally higher than normal in the late 1950s and early 1960s and in the early 1980s and has been rising throughout the 1990s when t p is observing the implication of the low frequency signals on the determination the secular rate of gmsl from satellite altimetry is discussed

dissolved inorganic carbon evolution in neutral discharge from mine tailings piles we measured the concentrations of dissolved inorganic carbon dic and major ions and the stable carbon isotope ratios of dic 13cdic in two creeks discharging from carbonate rich sulphide containing mine tailings piles our aim was to assess downstream carbon evolution of the tailings discharge as it interacted with the atmosphere the discharge had ph of 6 5 8 1 and was saturated with respect to carbonates over the reach of one creek the dic concentrations decreased by 1 1 mmol c l and 13cdic increased by 4 0 200 m from the seep source the decrease in the dic concentrations was concomitant with decreases in the partial pressure of co2 aq because of the loss of excess co2 aq from the discharge the corresponding enrichment in the 13cdic is because of kinetic isotope fractionation accompanying the loss of co2 g over the reach of the other creek there was no significant decrease in the dic concentrations or notable changes in the 13cdic the insignificant change in the dic concentrations and the 13cdic is because the first water sample was collected 160 m away from the discharge seep not accessible during this research in this case most of the excess co2 aq was lost before our first sampling station our results indicate that neutral discharges from tailings piles quickly lose excess co2 aq to the atmosphere and the dic becomes enrich in 13c we suggest that a significant amount of carbon cycling in neutral discharges from tailings piles occur close to the locations where the discharge seeps to the surface copyright 2015 john wiley sons ltd

a note on the representation of steric sea level in models that conserve volume rather than mass this note discusses the representation of steric sea level in ocean circulation models changes in steric sea level are caused when changes in the density of the water column imply an expansion or contraction of the column models usually make the boussinesq approximation and conserve volume rather than mass and so do not properly represent expansion or contraction this means that although expansion contraction is included in the equation of state it is not accounted for by the model dynamics in this note we examine the equation governing the time evolution of the sea level displacement it is shown that requiring conservation of mass rather than volume introduces a new term to this equation a simple example is used to show the relationship of the new term to the surface buoyancy flux the equilibrium response to the new term has two parts one part consists of the goldsbrough and stommel gyres for which in the ocean interior vortex stretching due to the local expansion contraction of the water column is balanced by changes in planetary vorticity the other part corresponds to the inverse barometer the effect is to adjust sea level by a globally uniform but timevarying factor determined by the net expansion contraction of the global ocean since this correction is globally uniform it has no dynamical significance both the goldsbrough stommel gyres and the inverse barometer solution are missing from models as currently formulated this does not represent a serious error however if comparison is made with observations of sea level model calculated sea level should be adjusted by a globally uniform time varying factor determined by the net expansion contraction of the global ocean this would be important for assessing the likely rise in sea level in response to global warming

hydrogeochemical and isotopic study of the kumho river korea implications for anthropogenic and seasonal effects the geochemical and isotopic compositions of river water are controlled by different factors the seasonal and spatial variations in the geochemical composition d 18o and 15n no3 of the kumho river were investigated to reveal the geochemical processes occurring at different seasons the kumho river which runs through different geologic terrains with different land use characteristics is the largest tributary of the nakdong river the longest river in south korea the data varied significantly according to the land use and the season each monitoring station showed the lowest concentrations of various ions during july the rainy season due to the increase of precipitation rate the ionic concentrations gradually increased downstream by the mineral weathering and anthropogenic activity at the upper regions of the river ca and hco3 which are closely associated with mineral weathering were the most dominant cation and anion respectively the relatively high si concentration of the headwater samples caused by the weathering of volcanic rocks also showed the importance of weathering in the upper regions mainly composed of volcanic rocks the downstream regions of the kumho river are mainly influenced by sedimentary rocks at the lower reaches of the river especially near the industrial complexes in daegu the third largest city in korea na cl and so4 became the dominant ions indicating that the anthropogenic pollution became more important in regulating the chemical composition of the river the increasing ca mg na k hco3 ratio downstream also indicates that the anthropogenic effects became more important as the river flows downstream the isotopic compositions of d and 18o indicate that the river waters were significantly affected by evaporation during may and july but the evaporation effect was relatively low during october the isotopic composition of 15n no3 increased downstream also confirming that anthropogenic effects became more significant at the lower reach of the river and near daegu

uranium isotopes as a tracer of sources of dissolved solutes in the han river south korea abstract the uranium u content and 234u 238u activity ratio were determined for water samples collected from korea s han river in spring summer and winter 2006 to provide data that might constrain the origin of u isotope fractionation in river water and the link between u isotope systematics in river waters and the lithological nature of the corresponding bedrock the large difference in the major dissolved loads between the two major branches of the han river the north han river nhr and south han river shr is reflected in the contrasting u content and 234u 238u activity ratio between the tributaries low u content 0 08 0 75 nm average 0 34 nm and small 234u 238u activity ratio 1 03 1 22 average 1 09 in the nhr and high u content 0 65 1 98 nm average 1 44 nm and large 234u 238u activity ratio 1 05 1 45 average 1 24 in the shr the large spatial differences in u content and 234u 238u activity ratio are closely related to both lithological differences between the two tributaries and groundwater input the low u content and small 234u 238u activity ratio in the nhr arise mainly from a combination of surface and meteoric weathering of the dominant silicate rocks in this branch and congruent dissolution of already weathered secular equilibrium materials in contrast the high u content and large 234u 238u activity ratio in the shr are ascribed to the dissolution of carbonates and black shales along with significant inputs of deep groundwater

stable isotopes in the source waters of the yamuna and its tributaries seasonal and altitudinal variations and relation to major cations water samples from the yamuna and its tributaries one of the major river systems draining the himalaya have been analysed for their stable oxygen and hydrogen isotopes during three seasons summer monsoon and post monsoon the data show clear seasonal and altitudinal variations waters from higher altitudes and those collected during monsoon season are characterized by relatively depleted isotopic composition regression analysis of d 18 o data of samples collected during summer and monsoon seasons shows that the slope of the best fit lines are nearly identical to those of precipitation at new delhi for the same period the similarity in their slopes suggests that the isotopic composition of precipitation contributing water to these rivers are reasonably well preserved in both monsoon and non monsoon seasons however during the non monsoon period both rainfall and river waters carry signatures of evaporation the deuterium excess in river waters during the three seasons though overlap with each other the values during october are higher this can be understood in terms of recycled moisture contributions to precipitation the altitude effect for 18 o in these waters is determined to be 0 11 per 100 m a factor of about two less than that reported for the ganga source waters from similar altitudinal range the variability in altitude effects in rivers draining the himalaya seems to be controlled by the amount effect associated with the monsoon the significant spatial variability in altitude effect in these river basins which are a few hundred kilometers apart suggests that reconstruction of palaeoelevation in the himalaya based on 18 o altitude gradients would depend critically on its proper assessment in the region this study has established a relationship between total cation abundance and 18 o in waters of the yamuna mainstream total cations corrected for cyclic components double for a 1 4 km decrease in altitude as the yamuna flows downstream

major element chemistry of the changjiang yangtze river the chemistry of major elements ca mg na k hco3 so4 cl and si in the river water of the changjiang yangtze river was studied based on continuously monitored data at 191 stations in the drainage basin for the period 1958 1990 the results show that the total dissolved solid tds concentration of the changjiang varies over an order of magnitude throughout the basin 49 7 518 1 mg l with a medium tds concentration of 205 9 mg l about three times the global average in contrast the tds at a given main channel station varies only slightly in different seasons with a variation factor less than 2 0 despite a substantial water dilution in the summer flood season the major element chemistry of the changjiang is mainly controlled by rock weathering with the anion hco3 and the cation ca dominating the major ion composition due to the abundance of carbonate rocks in the basin a persistently increasing trend has been observed in the concentrations of so4 and to a lesser extent cl in the changjiang a signature of considerable anthropogenic impacts e g acid deposition flux calculations at datong the most downstream main channel station without tidal influence indicate that the changjiang transports ca 154 106 tons year of tds to the sea second only to the amazon in the world

the fluvial geochemistry of the rivers of eastern siberia ii tributaries of the lena omoloy yana indigirka kolyma and anadyr draining the collisional accretionary zone of the verkhoyansk and cherskiy ranges fundamental to the global carbon cycle over geologic time scales is the control of atmospheric co2 by aluminosilicate weathering much of the information on the rates of this process comes from rivers in the tropics and subtropics to understand the possible climatic influences systematic studies are needed for the arctic subarctic regions this is the second in a series of papers addressing this problem by systematic studies of the pristine rivers of the russian far east the region to the east of the siberian platform huh et al 1998 is a geologically complex terrain formed by the mesozoic collision and accretion of the siberian and kolyma plates because of the arid continental climate it has not been glaciated in the recent past thus it is possible to study weathering processes in an arctic environment dominated solely by cryogenic interactions without contamination by heterogeneous components derived from scouring glaciers all the major rivers and their tributaries in this area have been sampled on expeditions to individual basins 100 samples on a reconnaissance basis at falling stage usually in july and august the total dissolved cation levels tz are moderate up to 3 100 eq and the major ion chemistry is indicative of ca aluminosilicate and carbonate weathering with significant contributions from black shales in some tributaries the si tz si na k and 87sr 86sr ratios indicate that the weathering is superficial i e only to cation rich secondary minerals the areal total dissolved solid fluxes range from 0 04 to 0 39 106 mol km2 yr up to an order of magnitude lower than for the amazon orinoco draining the andes in the tropics 0 6 4 1 106 mol km2 yr the co2 consumption by aluminosilicate weathering 18 230 103 mol km2 yr is also at the lower end of the range observed in the amazon orinoco headwaters 143 1 000 103 mol km2 yr however as the north american counterparts in similar latitudes and with comparable relief the mackenzie yukon and fraser draining the rockies also have high dissolved solids 0 2 2 9 106 mol km2 yr and co2 19 1 750 103 mol km2 yr fluxes these low values seem to be more a function of lithology than simply climate ice action in cold environments appears to overcome the inhibiting effects of the decreased temperatures and lack of precipitation in producing a high chemical yield but results in superficial weathering in the case of aluminosilicates

stable isotope ratios in precipitation and their relationship with meteorological conditions in the kumaon himalayas india summary for the first time environmental isotopic 2h 18o 3h data predominantly based on precipitation samples in the kumaon himalayas india have been used to understand the influence of various meteorological factors governing rainout processes in the region further the data are also used to understand the orographic effects in precipitation and to estimate the altitude effect in stable isotopic ratios in precipitation etc the interpretation of the isotopic data revealed that the source of moisture for winter october february and summer may precipitation in the kumaon himalayas is mainly from the western disturbances whereas for the remaining period the source is monsoonal southwest the 2 18o relationship in the local precipitation during the monsoon season shows a distinct seasonal effect with a slope of 7 6 the winter and summer precipitation samples measured higher environmental 3h compared to southwest monsoon samples thus indicating continental evaporated moisture there is wide range of altitude effects 18o variation per 100 m elevation 0 30 july august 0 57 september with the mean altitude effect being 2 61 and 0 36 per 100 m elevation for 2h and 18o respectively these values are different from that reported earlier for the region based on the isotopic compositions of springs rivers samples the altitude effect in successive precipitation is basically a temperature dependent phenomenon and is explained on the basis of adiabatic cooling related rainout process dry adiabatic lapse rate moist adiabatic lapse rate and saturated adiabatic lapse rate for moist air mass the altitude effect is found to be more reliable in case of 2 as deuterium is least affected by secondary evaporation the effect of secondary evaporation has been observed on the true altitude effect secondary evaporation of rainfall increases the oxygen isotopic ratios and the increase is directly proportional to the vertical distance travelled by the raindrops through air

soil n alkane δd vs altitude gradients along mount gongga china the altitude effect on the isotopic composition of precipitation and its application to paleoelevation reconstruction using authigenic or pedogenic minerals have been intensively studied however there are still no studies on variations in biomarker d along altitude transects to investigate its potential as a paleoelevation indicator although it has been observed that d of higher plant lipid may record changes in precipitation d dp here we present d values of higher plant derived c27 c29 and c31n alkanes from surface soil along the eastern slope of mount gongga china with great changes in physical variables and vegetation over a range from 1000 to 4000 m above sea level the weighted mean d values of these n alkanes dwax show significant linear correlations with predicted dp values r2 0 76 with an apparent isotopic enrichment ewax p of 137 9 indicating that soil dwax values track overall dp variation along the entire altitudinal transect leaf dwax is also highly correlated with mountain altitude by a significant quadratic relationship r2 0 80 evapotranspiration is found declining with altitude potentially lowering dwax values at higher elevations however this evapotranspiration effect is believed to be largely compensated by the opposing effect of vegetation changes resulting in less varied ewax p values over the slope transect this study therefore confirms the potential of using leaf dwax to infer paleoelevations and more generally to infer the d of precipitation

correlation of conductivity and stable isotope 18o for the assessment of water origin in river system when working on wetlands or other surface and subsurface water systems with multiple water sources it is not always easy to identify the mixing between the different waters here we have tried to adapt an easy technique i e conductivity but regularly standardised against stable natural isotope 18o to immediately give a glimpse on the field site of the percentage the two kinds of water in certain cases this method is also valid to discriminate a third source of water the first experimental site to be described is in a meander of the garonne river in south west france where there exists an interesting case of active paleo channels the second site is located in north india in the himalayas mountains garhwal at the source of the ganges river here the samples were taken to discriminate between snow and glacier melt

ocean dynamics associated with rapid j2 fluctuations importance of circumpolar modes and identification of a coherent arctic mode 1 fluctuations of the earth s dynamic oblateness j2 are a measure of global redistributions of mass between equatorial and polar regions sensitive to the component which is symmetric about the equator cox and chao recently published a time series of monthly values of j2 based on satellite orbit determination which showed rapid fluctuations from month to month as well as a large change in j2 in 1997 1998 we here investigate the ocean dynamics associated with these rapid fluctuations using a barotropic ocean model forced by atmospheric wind stress and pressure we find that the model has significant skill in reproducing the observations though not the change in 1997 1998 much of the model variability is related to coherent circumpolar fluctuations in arctic and antarctic bottom pressure which despite their apparent symmetry are forced by quite different mechanisms the antarctic mode is forced by circumpolar winds whereas the arctic mode is forced by northward winds over the entrances to the polar sea comparison with in situ observations shows that the model has skill in reproducing the polar modes arctic tide gauge records confirm the presence of a coherent mode at short periods and at long periods over at least the eurasian arctic shelf if barotropic and representative of the whole arctic this would be large enough to make a major contribution to measured j2 fluctuations but does not account for the 1997 1998 event

fe and mn levels regulated by agricultural activities in alluvial groundwaters underneath a flooded paddy field abstract iron and mn concentrations in fresh groundwaters of alluvial aquifers are generally high in reducing conditions reflecting low so4 concentrations the mass balance and isotopic approaches of this study demonstrate that reduction of so4 supplied from agricultural activities such as fertilization and irrigation is important in lowering fe and mn levels in alluvial groundwaters underneath a paddy field this study was performed to investigate the processes regulating fe and mn levels in groundwaters of a point bar area which has been intensively used for flood cultivation four multilevel groundwater samplers were installed to examine the relationship between geology and the vertical changes in water chemistry the results show that fe and mn levels are regulated by the presence of no3 at shallow depths and by so4 reduction at the greater depths isotopic and mass balance analyses revealed that no3 and so4 in groundwater are mostly supplied from the paddy field suggesting that the fe and mn rich zone of the study area is confined by the agricultural activities for this reason the geologic conditions controlling the infiltration of agrochemicals are also important for the occurrence of fe mn rich groundwaters in the paddy field area

stable isotopic variations in modern herbivore tooth enamel plants and water on the tibetan plateau implications for paleoclimate and paleoelevation reconstructions stable isotope analyses of fossil teeth and other authigenic minerals have been used to reconstruct the paleoenvironment and paleoelevation of the tibetan plateau the accuracy of such reconstructions is limited by the lack of a comprehensive modem comparative database from the region we analyzed the carbon and oxygen isotopic compositions delta c 13 and delta o 18 values of tooth enamel from modem herbivores the delta c 13 values of gasses and the delta o 18 values of water samples collected from various elevations within the tibetan plateau to examine their relationships with modem environment elevation the delta c 13 values of enamel samples from horses yaks and goats display a narrow range of variation with a mean of 10 7 1 4 parts per thousand n 301 indicating that these modem herbivores were feeding predominantly on c3 plants consistent with the current dominance of c3 vegetation in the region some of the samples have delta c 13 values between 7 3 and 10 parts per thousand although these higher delta c 13 values could suggest consumption of some c4 plants by the animals the lack of significant seasonal delta c 13 variations within individual teeth indicates that these higher enamel delta c 13 values are due to consumption of c3 plants experiencing water stress and or some cam plants rather than c4 plants our data show that the conservative cut off delta c 13 value for a pure c3 diet within the tibetan plateau should be 8 parts per thousand for modem herbivores and 7 parts per thousand or even 6 5 parts per thousand for fossils if the region was as and in the past as today in contrast to the small intra tooth delta c 13 variations within individual teeth serial enamel samples display large intra tooth delta o 18 variations reflecting seasonal variations in the delta o 18 of meteoric water the mean delta o 18 values of tooth enamel from yaks and horses show a strong correlation with water delta o 18 values confirming that the delta o 18 of tooth enamel from obligate drinker generally tracks the 6180 of meteoric water unfortunately elevation alone cannot explain most of the variance in the delta o 18 of precipitation and tooth enamel suggesting that quantitative reconstruction of the paleoelevation of the tibetan plateau using re constructed delta o 18 values of paleo meteoric water from fossil enamel or other oxygen bearing minerals is not warranted for a given environment horses have the lowest enamel delta o 18 values while goats display the highest enamel delta o 18 values among the species studied the large inter species delta o 18 variations are likely due to differences in physiology and diet drinking behavior of the animals this underscores the importance of species specific studies when interpreting delta o 18 data of fossil mammalian teeth in a stratigraphic sequence as a record of paleoclimate changes c 2008 elsevier b v all rights reserved

measuring gravity field variability the geoid ocean bottom pressure fluctuations and their dynamical implications 1 to obtain insight into bottom pressure variability and requirements for assimilating gravity data into an ocean general circulation model we use recent results from a constrained global model bottom pressure variability as contrasted to surface elevation variability is examined at the annual semiannual chandler wobble and 4 month periods surface elevation and bottom pressure variability occurs on all spatial and temporal scales resolvable by our analysis and patterns can be quite different a barotropic index developed to quantify variability character suggests the importance of steric effects at longer periods variability decomposition into standing eastward and westward traveling waves indicates a strong zonal component for both surface elevation and bottom pressure with bottom pressure showing a greater overall tendency toward eastward propagation and surface elevation showing a greater overall tendency toward westward propagation bottom pressure variability signals are estimated to be recoverable from space to spherical harmonic degree 27 for the annual cycle and 14 for the semiannual and chandler wobble cycles mass exchange arising from model approximations is detectable to about degree 7 polar motion excitation by ocean seafloor loading is found to be quantitatively important spurious oscillations encountered in using spherical harmonics to represent oceanic fields are suppressed using lanczos factors

weathering processes in the ganges brahmaputra basin and the riverine alkalinity budget abstract we present river chemistry data for a network of rivers draining the western and central nepal himalaya our sampling locations cover the system from the sources of rivers in tibet to the gangetic plain water samples were collected throughout the year including the monsoon season for rivers in nepal and for the ganges and brahmaputra in bangladesh rivers draining the north himalaya are characterized by low discharge under a cold and arid climate main stream waters have 13 c dic near 0 and high so42 so42 hco3 ratios xso4 with values around 40 eq and high cl ca is the dominant cation ca2 cations 55 to 75 eq after correction of sodium by chloride dissolved sulfate is produced in waters from the tethian sedimentary series whereas chlorine is related to thermal waters dissolved sulfate is primarily derived from sulfide oxidation rather than evaporite dissolution 13 c dic values of up to 3 9 show that metamorphic co2 is an important weathering agent rivers of the north himalayan basins have about 50 of their alkalinity derived from carbonate dissolution 20 from biogenic activity and 30 from metamorphic co2 on the south flank of the himalaya rivers are more depleted in 13 c and have on average lower xso4 most rivers have 13 c dic and xso4 values compatible with a simple mixing between soil co2 and sulfate derived from sulfide oxidation during the monsoon discharge increases by a factor 20 but the total dissolved concentration is only slightly reduced xso4 and 13 c decrease while ca cations increases implying enhanced dissolution of pedogenic calcite as a whole the g b riverine flux of alkalinity derived from silicate weathering is around 2 7 1011 mol year modest at the global scale sulphuric acid controls 20 30 of the weathering reaction in the brahmaputra and 6 to 9 in the ganges na and k balance 60 to 65 of the silicate derived alkalinity flux and the long term co2 consumption by ganges and brahmaputra is near 6 4 1010 mol year the flux of metamorphic co2 converted to alkalinity via weathering reactions is ca 1 1010 mol year

δ18o and δd systematics in the surficial waters of the gaula river catchment area kumaun himalaya india abstract the 18 o and d measurements of surface waters streams springs lakes and precipitation from the gaula river catchment area of kumaun himalaya are reported the d and 18 o values are positively correlated as has been the case with waters from several other regions the lake waters are found to be enriched in 18 o and d compared with the neighbouring regions owing to evaporation estimates of mean total evaporation during the dry season range from 10 to 25 spring water samples collected from various altitudes from 915 m to 2150 m display variations in values showing an altitude effect of 0 1491 per 100m elevation

predicting paleoelevation of tibet and the himalaya from δ18o vs altitude gradients in meteoric water across the nepal himalaya the 18o value of meteoric water varies with elevation providing a means to reconstruct paleoelevation if the 18o values of paleowater are known in this study we determined the 18o values of water 18omw from small tributaries along the seti river and kali gandaki in the nepal himalaya we found that 18omw values decrease with increasing altitude for both transects 18omw vs altitude along the kali gandaki in west central nepal fit a second order polynomial curve consistent with increasing depletion of 18o with increasing elevation as predicted by a rayleigh type fractionation process this modern 18omw vs altitude relationship can be used to constrain paleoelevation from the 18o values of miocene pliocene carbonate 18oc deposited in the thakkhola graben in the southern tibetan plateau paleoelevations of 3800 480 m to 5900 350 are predicted for the older tetang formation and 4500 430 m to 6300 330 m for the younger thakkhola formation these paleoelevation estimates suggest that by 11 ma the southern tibetan plateau was at a similar elevation to modern

using h and o isotopic data for estimating the relative contributions of rainy and dry season precipitation to groundwater example from cheju island korea abstract a comparison of deuterium excess or d values of precipitation and groundwater at cheju island korea indicates that unlike in many temperate climates precipitation during the whole year contributes to groundwater recharge this in turn suggests that evapotranspiration effects are minimal consistent with the fact that the island contains highly permeable volcanic rocks overlain by thin soils this hypothesis is contrary to current water budget models that ascribe a significant role to evapotranspiration processes three coastal springs and several streams and ponds throughout the island have enriched 18 o and d values that plot off the local meteoric water line and have relatively high cl concentrations this relationship is suggestive of seawater mixing for the coastal springs and evaporation for the streams and ponds this database thus provides a useful means for evaluation of groundwater resources of the island

variations in the earth s oblateness during the past 28 years 1 analysis of satellite laser ranging slr data indicates that the earth s dynamic oblateness j2 has undergone significant variations during the past 28 years the dominant signatures in the observed variations in j2 are 1 a secular decrease with a rate of approximately 2 75 10 11 yr 1 2 seasonal annual variations with a mean amplitude of 2 9 10 10 3 significant interannual variations with timescales of 4 6 years and 4 a variation with period of 21 years and an amplitude of 1 4 10 10 with minimum in december 1988 two large interannual variations are related to the strong el nino southern oscillation events during the periods of 1986 1991 and 1996 2002 and it appears that another interannual cycle may have started in late 2002 the superposition of the decadal variation on the interannual signal makes the j2 fluctuation appear to be anomalously large during the 1996 2002 period contemporary models of the mass redistributions in the atmosphere ocean and surface water can explain a major part of the 4 to 6 year fluctuations however the cause of the decadal variation remains unknown

characteristics of isotope in precipitation river water and lake water in the manasarovar basin of qinghai tibet plateau the stable hydrogen and oxygen of lake river rain and snow waters were investigated to understand the water cycle characteristics of the drainage basin of manasarovar lake in tibet both d and 18o of river water are larger than those of lake water and the effect of altitude on both d and 18o is not very significant this phenomenon was suggested to occur because manasarovar basin is located in qinghai tibet plateau which has low latitude high altitude abundant glaciers thin air and intensive solar radiation resulting in higher evaporation in lake water

detection of a large scale mass redistribution in the terrestrial system since 1998 earth9s dynamic oblateness j2 had been undergoing a decrease according to space geodetic observations over the past 25 years until around 1998 when it switched quite suddenly to an increasing trend that has continued to the present the secular decrease in j2 resulted primarily from the postglacial rebound in the mantle the present increase whose geophysical cause s are uncertain thus signifies a large change in global mass distribution with a j2 effect that considerably overshadows that of mantle rebound

oxygen isotope composition of fjord and river water in the sognefjorden drainage area western norway implications for paleoclimate studies abstract during two cruises and one field expedition from 1996 to 1998 32 water samples from 10 stations in sognefjorden and tributary fjords and six samples from rivers draining into the fjord were obtained for oxygen isotope measurements in addition ctd profiles were obtained from all of the fjord locations the river samples show a large gradient in the oxygen isotopic composition from the outer fjord region to the rivers at the fjord head the difference is more than 6 with highest values recorded at the fjord mouth decreasing inward along the fjord the low oxygen isotope values are found in areas with a high altitude from the watershed the gradient in the river water is explained by distance to the moisture source topographic effects and temperature of precipitation the isotopic composition of the fjord waters suggest a mixing line for sognefjorden of 0 31 for a salinity change of 1 which is slightly higher than the north sea mixing line israelson buchardt 1991 and lower than the north atlantic mixing line craig gordon 1965 the river samples are not used in the calculation of the mixing because of the large differences in the isotopic composition of river water along the fjord and large seasonal differences of precipitation

carbon fluxes pco2 and substrate weathering in a large northern river basin canada carbon isotope perspectives abstract isotopic composition of dissolved inorganic carbon 13 c dic in the ottawa river basin is about 8 and 16 for lowland carbonate and upland silicate tributaries respectively this suggests that 1 the source of dic to the ottawa river is soil respiration and carbonate weathering 2 exchange with the atmosphere is unidirectional or volumetrically unimportant and 3 in river respiration and photosynthesis are not significant influences on the river carbon budget accepting these constraints chemical and isotopic data are used to reconstitute soil pco2 for tributary catchments averages for upland silicate mixed and lowland carbonate basins are calculated to be roughly 2000 5000 and 30 000 ppm respectively these values are used as input to model the pathway of carbon through the watershed rain water to soil water to river water the flux of carbon from the ottawa river as dic is calculated to be 4 3 1010 mol c a utilizing carbon isotopes 75 and 25 of the ca2 mg2 flux is calculated to originate from carbonate and silicate weathering respectively and 61 of the dic is calculated to originate from organic respiration the latter represents some 6 of respired carbon in the basin assuming an average respiration rate of 0 5 mmol c m 2 h 1 based on a diffusion model co2 evasion to the atmosphere from the ottawa river and its tributaries is estimated to be 1 3 1010 mol c a or 30 of the dic flux

estimation of steric sea level variations from combined grace and jason 1 data abstract we estimate the mean steric sea level variations over the 60 s 60 n oceanic domain for the recent period from august 2002 to april 2006 by combining sea level data from jason 1 altimetry with time variable gravity data from grace the observed global mean sea level change from satellite altimetry results in total from steric plus ocean mass change as grace measurements averaged over the ocean represents the ocean mass change component only the difference between grace and altimetry observations provides an estimate of the mean steric sea level two different sets of grace geoid solutions the grgs eigen gl04 and the gfz eigen grace04s products have been used each grace data set ranges over approximately 3 yr or more august 2002 april 2006 for the grgs geoids and february 2003 february 2006 for the gfz geoids we first focus on the seasonal variations the two grace data sets agree very well in terms of mean annual mass variation both in amplitude approximately 7 3 mm equivalent sea level and phase maximum on october 14 for both time spans jason 1 sea level minus grace ocean mass has an annual amplitude of approximately 5 8 mm with a maximum on march 11 the latter signal compares well with the steric annual sea level estimated from the world ocean 2004 climatology and the ishii et al m ishii m kimoto k sakamoto and s i iwasaki steric sea level changes estimated from historical ocean subsurface temperature and salinity analyses journal of oceanography 62 2 2006 155 170 ocean temperature data we also examine the interannual fluctuations of the jason 1 minus grace sea level the two resulting steric sea level time series based on the two grace data sets agree well the inferred steric sea level curve exhibits an increasing trend during the last 3 5 yr august 2002 april 2006 of the same order of magnitude as the 1993 2003 steric sea level trend computed with in situ hydrographic data however over the last 3 5 yr we note a strong discrepancy between altimetry minus grace and in situ based steric sea level trend the latter exhibiting a negative slope the cause for such a discrepancy is yet unknown but may be related to inadequate sampling of in situ ocean temperature measurements

chemical weathering of carbonates and silicates in the han river basin south korea abstract a detailed investigation of the fluvial geochemistry of the han river system allows to estimate the rates of chemical weathering and the consumption of co 2 the han river drains approximately 26 000 km 2 and is the largest river system in south korea in terms of both water discharge and total river length it consists of two major tributaries the north han river nhr and the south han river shr distinct differences in basin lithology silicate vs carbonate between the nhr and shr provide a good natural laboratory in which to examine weathering processes and the influence of basin geology on water quality the concentrations of major elements and the sr isotopic compositions were obtained from 58 samples collected in both summer and winter along the han river system in both 2000 and 2006 the concentrations of dissolved loads differed considerably between the nhr and shr compared with the shr the nhr had much lower total dissolved solids tds sr and major ion concentrations but a higher si concentration and 87 sr 86 sr ratio a forward model showed that the dissolved loads in the nhr came primarily from silicate weathering 55 11 with a relatively small portion from carbonates 30 14 whereas the main contribution to the dissolved loads in the shr was carbonate weathering 82 3 with only 11 4 from silicates these results are consistent with the different lithologies of the two drainage basins silicate rocks in the nhr versus carbonate rocks in the shr sulfuric acid derived from sulfide dissolution in coal containing sedimentary strata has played an important role in carbonate weathering in the shr basin unlike in the nhr basin the silicate weathering rate swr was similar between the nhr and shr basins but the rate of co 2 consumption in the shr basin was lower than in the nhr basin due to an important role of sulfuric acid derived from pyrite oxidation

chemical and physical weathering in the min jiang a headwater tributary of the yangtze river abstract the min jiang is a major headwater tributary of the yangtze chang jiang its source is in the undeveloped eastern tibetan plateau but it flows through the heavily populated sichuan four rivers basin on its way to join the yangtze main channel the dissolved major element composition was determined in the tibetan headwaters at the rising stage and at four hydrologic stations in a monthly time series the min jiang is alkaline and has high dissolved load compared to other world rivers carbonate weathering dominates especially in the source region of the min jiang main channel and silicate weathering and evaporite dissolution gain some importance in the dadu he tributary the si na k ratios of the dissolved load and the clay mineralogy of the bed material suggest that silicate weathering in the watershed is superficial i e soluble cations are being preferentially leached many major elements show lower concentrations at high summer discharge but there is also additional input such that the concentration discharge relationship is not purely a result of dilution the discharge weighted total dissolved solid tds flux based on data from the three upstream monitoring stations is 10 10 6 tons year 6 of the yangtze at mouth and the chemical denudation rate as measured by tds yield is 115 tons km 2 year for the min jiang higher than the average yangtze basin 85 tons km 2 year the common extrapolation using annual average discharge and spot sampling of dissolved and suspended material during rising or falling stage can reasonably estimate chemical fluxes to 20 but seriously underestimate the physical flux sampling the peak flash flow is critical for the suspended particulate material concentrations of so 4 cl and ca are significantly elevated as the river debouches onto the populated sichuan basin

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

sea level response to pressure forcing in a barotropic numerical model abstract a barotropic shallow water model is used to study the large scale sea level response to realistic barometric forcing at periods ranging from 1 day to 1 year results are presented from coarse resolution open ocean experiments i e no shallow continental shelf regions or marginal seas with coastal geometries and bottom topography representative of the north atlantic and pacific basins the validity of the inverted barometer ib approximation is examined in detail including nonlocal effects which result from taking into account the constant volume of the ocean these effects are found to be important at low latitudes where a considerable part of the sea level variability is related to pressure forcing over higher latitudes root mean square deviations from an ib response in the range of 1 3 cm are typical with most of the variance occurring at high frequencies basin averaged estimates yield ib deviations of only a few percent at time scales longer than 1 week increasing to 5 20 over the

el nino southern oscillation signals in sea level surface mass redistribution and degree two geoid coefficients 1 we use a coupled earth system model to simulate and quantify the impact of the el nino southern oscillation enso on monthly to interannual variations of steric and eustatic global mean sea level gmsl surface mass loading and on the corresponding degree two geoid coefficients c21 s21 and c20 gmsl is dominated by eustatic variations on monthly to interannual timescales but less than 10 of the eustatic variance is related to enso in contrast steric gmsl correlates linearly in phase with enso with an explained variance of nearly 46 together these results imply that total gmsl variations are only weakly correlated with enso despite this small correlation we find a distinct enso pattern of sizable surface mass load anomalies over the continents this pattern is similar to typical enso related precipitation anomalies over the oceans the pattern features a global albeit weaker response with generally increased loading in the arctic and pacific oceans and decreased loading in the atlantic and indian oceans these surface loading anomalies lead to statistically significant enso related variations in the s21 and c20 geoid coefficients but not in c21 in analyzing the individual subsystem contributions we find that s21 is influenced by both ocean mass redistribution and soil moisture loading whereas c20 is mainly influenced by soil moisture loading our results highlight the importance of high amplitude regional loading anomalies that integrate to low degree geoid anomalies

water balance of the indus river basin and moisture source in the karakoram and western himalayas implications from hydrogen and oxygen isotopes in river water 1 stable isotope measurements of hydrogen and oxygen for surface waters from the indus river basin irb together with historical records for river discharge annual precipitation and groundwater levels are used to assess water balance for the basin the indus river presently drains 53 km3 yr 1 or roughly one eighth of the 398 km3 water that annually falls on the basin in the form of rain and snow with the remainder returned to the atmosphere by evapotranspiration monthly samples for the indus river close to its mouth for the water year march 1994 to february 1995 show a tight correlation in d and 18o space the slope of the linear regression is 7 5 which is not significantly different from the slopes of the local meteoric water lines lmwl 7 3 and 7 1 this observation argues against significant loss of water by direct evaporation from river surfaces or from soils in hydrologic continuum with surface waters an upper limit for evaporation from poorly drained soils is calculated to be 10 km3 yr 1 or only 2 5 of the annual precipitation flux groundwater storage in the entire canal command area received a maximum of 23 km3 yr 1 or 5 8 of the annual precipitation during the early stages of irrigation but modern recharge is probably balanced by discharge to rivers and well exploitation transpiration by natural vegetation and crops annually returns 83 of the precipitation flux and constitutes the largest pathway for the loss of water from the basin deuterium excess d excess in the irb ranges between 4 and 28 with values for 95 of the sample population exceeding 10 the indus main channel close to its mouth varies in d excess between 12 and 20 during low and high water stands respectively with a discharge weighted average of 18 these values are distinctly higher than the long term average for the indian monsoon 8 and reflect contributions from water vapor originating in the mediterranean 22 or other inland seas using these end member compositions and the discharge weighted average d excess isotope balance calculations require that up to 72 of the indus discharge close to its mouth must be derived from the mediterranean end member and implies that bulk of the indus discharge is the result of delayed runoff from the karakoram and the himalayas

stable isotope paleoaltimetry a critical review stable isotope paleoaltimetry makes use of systematic trends in the distribution and isotopic composition of modern precipitation with climate and topography and of the potential to estimate the isotopic composition of paleoprecipitation from authigenic in situ formed minerals to illustrate the usefulness as well as potential limitations of this method we review 1 processes controlling the isotopic composition of modern precipitation 2 stable isotope data from modern precipitation across regions of high topography and 3 stable isotope data from authigenic minerals that have been used to infer paleotopography from this we conclude that stable isotope studies of authigenic minerals can permit useful inferences on paleotopography with uncertainties that critically depend on a detailed understanding of local to global scale paleoclimate during the time interval of interest

geochemistry of the amazon 1 precipitation chemistry and the marine contribution to the dissolved load at the time of peak discharge analyses of precipitation and surface water are used to estimate the fluxes of marine cyclic salts through that part of the amazon river system draining past obidos 80 of the basin at the time of peak discharge in june amazon precipitation chemistry can be devided into two principal components marine and terrestrial the marine component determined from analyses of marine rain consists of na k mg ca and cl in approximately sea salt proportions with s doubly enriched the excess sulfur is probably derived from gas phase inputs the terrestrial component makes an important contribution of k ca s and n much of which can be related to biological emissions the emission of reduced sulfur in the marine and terrestrial environment and nitrogen in the terrestrial environment is responsible for a natural acid rain in the amazon region with a ph from 4 7 to 5 7 this is about one tenth the acidity of polluted urban rain the chloride content of lowland rivers which drain regions lacking significant geologic sources of chloride shows a systematic decrease in chloride with increasing distance from the ocean this trend is used to define the cyclic salt background for amazonian surface waters cyclic salts in general make only a minor contribution relative to terrestrial inputs to the chemistry of amazon basin rivers even those draining intensely weathered terrains an estimated 17 6 cl 6 9 na 1 3 mg 3 6 s 0 4 k and 0 1 ca of the dissolved load at obidos during peak discharge is cyclic

investigation of point source pollution by chlorinated solvents in two different geologies a multi layered carboniferous sandstone mudstone sequence and the chalk

reconstructing the paleotopography of mountain belts from the isotopic composition of authigenic minerals the paleorelief of mountain belts can be estimated from the 18 o value of authigenic minerals development of relief during mountain building often creates lee side rain shadows in which precipitation is depleted in 18 o and d the magnitude of this rain shadow effect is strongly correlated to relief a compilation of 18 o data from surface waters throughout the globe shows a linear relationship between net elevation change and 18 o r 2 0 79 through the use of this relationship we investigated the timing and magnitude of elevation change in the southern alps of new zealand and the sierra nevada of california the 18 o values of kaolinites from new zealand show an 6 decrease in the early pliocene that corresponds to an 2 km elevation change in the southern alps the 18 o of smectites from the sierra nevada show little change since 16 ma suggesting that these mountains have been a long standing topographic feature

the correlation between 18o 16o ratios of meteoric water and surface temperature its use in investigating terrestrial climate change over geologic time abstract correlations between mean annual temperature mat and the weighted average oxygen isotope composition of yearly precipitation 18opt are well known but the utility of modern relations to make reliable estimates of temperature change over geological time is uncertain this question has been addressed by using seasonal subsets of the global data base of temperature and isotopic measurements to represent two different climate modes a comparison of middle to high latitude 18opt temperature relations for each climate mode reveals 1 a significant offset between them and 2 a difference in the strength of their correlations the offset in relations is due to differences in temperature and water vapor budget in the tropics and can lead to serious underestimates of temperature change differences in the strength of correlations arise from the influence of climate mode specific non temperature factors on 18opt the overall result is that no single relation can be used in all cases to make unambiguous temperature estimates using a temporal record of 18opt values one way to overcome these problems is to reconstruct 18opt temperature relations for the time periods being investigated if an appropriate proxy for 18opt is available it may also be possible to estimate temperature without relying on 18opt temperature relations a promising alternative to these options is to use records of 18opt to test predictions of global climate models an approach that may allow a reliable and more complete reconstruction to be made of climate change over geologic time

worldwide distribution of continental rock lithology implications for the atmospheric soil co2 uptake by continental weathering and alkalinity river transport to the oceans 1 the silicate rock weathering followed by the formation of carbonate rocks in the ocean transfers co2 from the atmosphere to the lithosphere this co2 uptake plays a major role in the regulation of atmospheric co2 concentrations at the geologic timescale and is mainly controlled by the chemical properties of rocks this leads us to develop the first world lithological map with a grid resolution of 1 1 this paper analyzes the spatial distribution of the six main rock types by latitude continents and ocean drainage basins and for 49 large river basins coupling our digital map with the gem co2 model we have also calculated the amount of atmospheric soil co2 consumed by rock weathering and alkalinity river transport to the ocean among all silicate rocks shales and basalts appear to have a significant influence on the amount of co2 uptake by chemical weathering

modern precipitation stable isotope vs elevation gradients in the high himalaya comment on a new approach to stable isotope based paleoaltimetry implications for paleoaltimetry and paleohypsometry of the high himalaya since the late miocene by david b rowley et al earth planet sci lett 188 2001 253 268

hydrogeochemical and isotopic investigations of the han river basin south korea summary the han river the largest river in south korea draining approximately 26 000 km 2 comprises two major tributaries the north and the south han rivers seasonal and spatial variations in the major ion chemistry and isotope compositions of the han river were monitored for one year at 14 23 locations covering about 80 of the entire drainage basin compared to the south han river shr the north han river nhr was much lower in total dissolved solids tds sr and major ion concentrations but higher in si concentration 34 s so 4 values and 87 sr 86 sr ratios these observations suggest strong influence of prevailing rock types in the drainage basins on the chemical and isotopic compositions of the river waters these are silicate rocks in the nhr basin and carbonate rocks in the shr basin the headwaters of the nhr basin where several flood control dams have been constructed show enrichment in deuterium and oxygen 18 indicating evaporative loss the 34 s so 4 data suggest dissolved sulfates in the nhr and shr are mostly derived from atmospheric deposition and variable mixtures of atmospheric deposition and sulfide oxidation respectively the 87 sr 86 sr ratios are much higher in the nhr 0 71793 0 72722 than in the shr 0 71495 0 71785 with one exception indicating weathering of precambrian and mesozoic granitic rocks and marine carbonates respectively

twentieth century sea level an enigma changes in sea level relative to the moving crust are associated with changes in ocean volume mostly thermal expansion and in ocean mass melting and continental storage t steric t eustatic t recent compilations of global ocean temperatures by levitus and coworkers are in accord with coupled ocean atmosphere modeling of greenhouse warming they yield an increase in 20th century ocean heat content by 2 1023 j compared to 0 1 1023 j of atmospheric storage which corresponds to greenhouse 2000 3 cm the greenhouse related rate is accelerating with a present value greenhouse 2000 6 cm century tide records going back to the 19th century show no measurable acceleration throughout the late 19th and first half of the 20th century we take historic 18 cm century the intergovernmental panel on climate change attributes about 6 cm century to melting and other eustatic processes leaving a residual of 12 cm of 20th century rise to be accounted for the levitus compilation has virtually foreclosed the attribution of the residual rise to ocean warming notwithstanding our ignorance of the abyssal and southern oceans the historic rise started too early has too linear a trend and is too large melting of polar ice sheets at the upper limit of the intergovernmental panel on climate change estimates could close the gap but severe limits are imposed by the observed perturbations in earth rotation among possible resolutions of the enigma are a substantial reduction from traditional estimates including ours of 1 5 2 mm y global sea level rise a substantial increase in the estimates of 20th century ocean heat storage and a substantial change in the interpretation of the astronomic record