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  • Coastal aquifer system in late Pleistocene to Holocene deposits at Horonobe in Hokkaido, Japan

    Peer Reviewed Literature
    Water Isotope Analyzers

    The groundwater flow systems and chemistry in the deep part of the coastal area of Japan have attracted attention over recent decades due to government projects such as geological disposal of radioactive waste. However, the continuous groundwater flow system moving from the shallow to deep parts of the sedimentary soft rock has not yet been characterized.

  • Recent accumulation variability in northwest Greenland from ground-penetrating radar and shallow cores along the Greenland Inland Traverse

    Peer Reviewed Literature
    Water Isotope Analyzers

    Accumulation is a key parameter governing the mass balance of the Greenland ice sheet. Several studies have documented the spatial variability of accumulation over wide spatial scales, primarily using point data, remote sensing or modeling. Direct measurements of spatially extensive, detailed profiles of accumulation in Greenland, however, are rare. We used 400 MHz ground-penetrating radar along the 1009 km route of the Greenland Inland Traverse from Thule to Summit during April and May of 2011, to image continuous internal reflecting horizons.

  • Stable Isotope Analysis of Precipitation Samples Obtained via Crowdsourcing Reveals the Spatiotemporal Evolution of Superstorm Sandy

    Peer Reviewed Literature
    Water Isotope Analyzers

    Extra-tropical cyclones, such as 2012 Superstorm Sandy, pose a significant climatic threat to the northeastern United Sates, yet prediction of hydrologic and thermodynamic processes within such systems is complicated by their interaction with mid-latitude water patterns as they move poleward. Fortunately, the evolution of these systems is also recorded in the stable isotope ratios of storm-associated precipitation and water vapor, and isotopic analysis provides constraints on difficult-to-observe cyclone dynamics.

  • Carbon Sequestration and Fertility after Centennial Time Scale Incorporation of Charcoal into Soil

    Peer Reviewed Literature
    Carbon Isotope Analyzers

    The addition of pyrogenic carbon (C) in the soil is considered a potential strategy to achieve direct C sequestration and potential reduction of non-CO2 greenhouse gas emissions. In this paper, we investigated the long term effects of charcoal addition on C sequestration and soil physico-chemical properties by studying a series of abandoned charcoal hearths in the Eastern Alps of Italy established in the XIX century. This natural setting can be seen as an analogue of a deliberate experiment with replications.

  • CO2 and CH4 in sea ice from a subarctic fjord

    Peer Reviewed Literature
    Gas Concentration Analyzers

    We present CH4 concentration [CH4] and the partial pressure of CO2 (pCO2) in bulk sea ice from subarctic, land-fast sea ice in the Kapisillit fjord, Greenland. The bulk ice [CH4] ranged from 1.8 to 12.1 nmol L−1, which corresponds to a partial pressure range of 3 to 28 ppmv. This is markedly higher than the average atmospheric methane content of 1.9 ppmv. Most of the trapped methane within the sea ice was evidently contained inside bubbles, and only a minor portion was dissolved in the brine.

  • Understanding mean transit times in Andean tropical montane cloud forest catchments: combining tracer data, lumped parameter models and uncertainty analysis

    Peer Reviewed Literature
    Water Isotope Analyzers

    Weekly samples from surface waters, springs, soil water and rainfall were collected in a 76.9 km2 mountain rain forest catchment and its tributaries in southern Ecuador. Time series of the stable water isotopes δ18O and δ2H were used to calculate mean transit times (MTTs) and the transit time distribution functions (TTDs) solving the convolution method for seven lumped parameter models.

  • An attempt at estimating Paris area CO2 emissions from atmospheric concentration measurements

    Peer Reviewed Literature
    Gas Concentration Analyzers

    Atmospheric concentration measurements are used to adjust the daily to monthly budget of CO2 emissions from the AirParif inventory of the Paris agglomeration. We use 5 atmospheric monitoring sites including one at the top of the Eiffel tower. The atmospheric inversion is based on a Bayesian approach, and relies on an atmospheric transport model with a spatial resolution of 2 km with boundary conditions from a global coarse grid transport model.

  • Toward a better understanding and quantification of methane emissions from shale gas development

    Peer Reviewed Literature
    Gas Concentration Analyzers

    The identification and quantification of methane emissions from natural gas production has become increasingly important owing to the increase in the natural gas component of the energy sector. An instrumented aircraft platform was used to identify large sources of methane and quantify emission rates in southwestern PA in June 2012. A large regional flux, 2.0–14 g CH4 s−1 km−2, was quantified for a ∼2,800-km2 area, which did not differ statistically from a bottom-up inventory, 2.3–4.6 g CH4 s−1 km−2.

  • Drilling and sampling a natural CO2 reservoir: Implications for fluid flow and CO2-fluid-rock reactions during CO2 migration through the overburden

    Peer Reviewed Literature
    Water Isotope Analyzers

    This paper presents the initial results of a scientific drilling project to recover core and pressurized fluid samples from a natural CO2 reservoir, near the town of Green River, Utah. The drilling targeted a stacked sequence of CO2-charged Jurassic sandstone reservoirs and caprocks, situated adjacent to a CO2-degassing normal fault. This site has actively leaked CO2 from deep supercritical CO2 reservoirs at depth > 2 km within the basin for over 400,000 years.

  • Stable isotopes in river waters in the Tajik Pamirs: regional and temporal characteristics

    Peer Reviewed Literature
    Water Isotope Analyzers

    The Gunt River catchment in the Central Pamirs is a representative of the headwater catchments of the Aral Sea Basin. It covers 14,000 km2, spanning altitudes between 2000 and 6700 m a.s.l. In a monitoring network, water samples were taken at 30 sampling points every month and analysed for the stable water isotopes (18O and 2H). Our first results show δ2H values in the range from−131.2 to−94.9 ‰ and δ18O values from−18.0 to−14.0 ‰.

  • A first chronology for the North Greenland Eemian Ice Drilling (NEEM) ice core

    Peer Reviewed Literature
    Gas Concentration Analyzers

    A stratigraphy-based chronology for the North Greenland Eemian Ice Drilling (NEEM) ice core has been derived by transferring the annual layer counted Greenland Ice Core Chronology 2005 (GICC05) and its model extension (GICC05modelext) from the NGRIP core to the NEEM core using 787 match points of mainly volcanic origin identified in the electrical conductivity measurement (ECM) and dielectrical profiling (DEP) records.

  • Paleoclimate record in the Nubian Sandstone Aquifer, Sinai Peninsula, Egypt

    Peer Reviewed Literature
    Water Isotope Analyzers

    Sixteen groundwater samples collected from production wells tapping Lower Cretaceous Nubian Sandstone and fractured basement aquifers in Sinai were analyzed for their stable isotopic compositions, dissolved noble gas concentrations (recharge temperatures), tritium activities, and 14C abundances.

  • Origin and evolution characteristics of geothermal water in the Niutuozhen geothermal field, North China Plain

    Peer Reviewed Literature
    Water Isotope Analyzers

    Statistical study of analyses of water from 43 samples from geothermal wells, three groundwater wells, and one sample of local rainwater along with rainwater data from the Global Network of Isotopes in Precipitation has been used to identify the origin and evolution of geothermal water in the Niutuozhen (牛驼镇) geothermal field and estimate the renewability rate of its geothermal resource.

  • Performance assessment of a cavity ring-down laser spectrometer: achieving better precision and accuracy in the measurement of δ18O and δ2H in liquid water samples

    Peer Reviewed Literature
    Water Isotope Analyzers

    The development of new isotopic laser-based analyzers currently represents a clear alternative to conventional isotope ratio mass spectrometers. However, this analytical technique also suffers some disadvantages such as the memory effect, problems related to the overall stability of the equipment and other issues associated with the injection system, essentially regarding the syringe's longevity. This paper aims to minimize these disadvantages in order to increase the overall performance, in terms of precision and accuracy, of these kinds of analyzers.

  • Spatial and Temporal Variation of Stable Isotopes in Precipitation across Costa Rica: An Analysis of Historic GNIP Records

    Peer Reviewed Literature
    Water Isotope Analyzers

    The location of Costa Rica on the Central American Isthmus creates unique microclimate systems that receive moisture inputs directly from the Caribbean Sea and the Pacific Ocean. In Costa Rica, stable isotope monitoring was conducted by the International Atomic Energy Agency and the World Meteorological Association as part of the worldwide effort entitled Global Network of Isotopes in Precipitation. Sampling campaigns were mainly comprised of monthly-inte- grated samples during intermittent years from 1990 to 2005.

  • Guano-derived d13C-based paleo-hydroclimate record from Gaura cu Musca Cave, SW Romania

    Peer Reviewed Literature
    Carbon Isotope Analyzers

    The δ13C values of 23 unevenly spaced guano samples from a 17-cm long clay sediment profile in Gaura cu Musca Cave (GM), in SW Romania, made it possible to preliminarily characterize the Medieval Warm Period summer hydroclimate regime. The beginning of the sequence (AD 990) was rather wet for more than a century, before becoming progressively drier.

  • A multitower measurement network estimate of California’s methane emissions

    Peer Reviewed Literature
    Gas Concentration Analyzers

    We present an analysis of methane (CH4) emissions using atmospheric observations from five sites in California’s Central Valley across different seasons (September 2010 to June 2011).

  • The nocturnal water cycle in an open-canopy forest

    Peer Reviewed Literature
    Water Isotope Analyzers

    The movement of moisture into, out-of, and within forest ecosystems is modulated by feedbacks that stem from processes which couple plants, soil, and the atmosphere. While an understanding of these processes has been gleaned from Eddy Covariance techniques, the reliability of the method suffers at night because of weak turbulence.

  • A test of the advection-condensation model for subtropical water vapor using stable isotopologue observations from Mauna Loa Observatory, Hawaii

    Peer Reviewed Literature
    Water Isotope Analyzers

    Subtropical humidity plays a critical role in the radiative balance of the planet, and there is a need for adequate description of the controls on water vapor distributions. This study tests whether an advection-condensation model, combined with Rayleigh distillation, can describe observed humidity and water vapor isotope ratios of the subtropical free troposphere. A field campaign, from 9 October to 6 November, 2008, included continuous in situ measurement of water vapor stable isotope ratios at the NOAA Mauna Loa Observatory (MLO), Hawaii.

  • Root niche partitioning among grasses, saplings, and trees measured using a tracer technique

    Peer Reviewed Literature
    Water Isotope Analyzers

    Niche partitioning of resources by plants is believed to be a fundamental aspect of plant coexistence and biogeochemical cycles; however, measurements of the timing and location of resource use are often lacking because of the difficulties of belowground research. To measure niche partitioning of soil water by grasses, planted saplings, and trees in a mesic savanna (Kruger National Park, South Africa), we injected deuterium oxide into 102,000 points in 15, 154-m2 plots randomly assigned to one of five depths (0–120 cm) and one of three time periods during the 2008/2009 growing season.

  • Water isotopic variability in response to mesoscale convective system over the tropical ocean

    Peer Reviewed Literature
    Water Isotope Analyzers

    In tropical regions, the empirical negative relationship between the isotopic content of precipitation and rainfall amount, known as the 'amount effect', has been used as a rationale for paleo-hydroclimate reconstruction from isotope records. However, there is still no comprehensive physical explanation for this empirical effect. Here, we reconsider the well-known amount effect using newly available isotope data for both surface water vapor and precipitation obtained from shipboard observations.

  • Estimation of soil water evaporative loss after tillage operation using the stable isotope technique

    Peer Reviewed Literature
    Water Isotope Analyzers

    Application of stable isotopes in soil studies has improved quantitative evaluation of evaporation and other hydrological processes in soil. This study was carried out to determine the effect of tillage on evaporative loss of water from the soil. Zero tillage and conventional tillage were compared. Suction tubes were installed for soil water collection at the depths 0.15, 0.50, and 1.0 m by pumping soil water with a peristaltic pump. Soil water evaporation was estimated using stable isotopes of water.

  • Vegetation induced changes in the stable isotope composition of near surface humidity

    Peer Reviewed Literature
    Water Isotope Analyzers

    Obtaining the d-excess parameter from the oxygen (O) and hydrogen (H) stable isotope composition of meteoric waters has the potential power to reconstruct changes in atmospheric water pools (e,g, sources, origins and overall balance) and the climatic conditions that prevail during surface evaporation. Only recently have plant and ecosystem scientists turned their attention to using d-excess information to inform questions at these scales.

  • A synthesis of hydrogen isotope variability and its hydrological significance at the Qinghai–Tibetan Plateau

    Peer Reviewed Literature
    Water Isotope Analyzers

    Hydrogen isotope ratios of sedimentary biomarkers are known to record the climatic variability in terrestrial and marine environments. However, there is still a lack of calibration studies that can quantitatively retrace the driving forces, especially at the Tibetan Plateau. Here, we elaborate the actual influence of environmental parameters such as temperature, evapotranspiration, salinity and biosynthetic fractionation on δD values of n-alkanes.

  • Monthly d18O, dD and Cl- characteristics of precipitation in the Ndop plan, Northwest Cameroon: Baseline data

    Peer Reviewed Literature
    Water Isotope Analyzers

    Knowledge of stable isotopes and chemical tracers in meteoric water has been used as a valuable tool in various environmental studies. A systematic monthly sampling of precipitation, in the Ndop plain, was carried out to generate basic data on δ18, δD and Cl−, determine their seasonal variations and controlling factors to be used as baseline data in hydrological and climatological studies. The δ18O–δD relationship of rainfall gives a regression line: δD = 7.93 δ18O + 13.26 (R2 = 0.99), which represents the Ndop Meteoric Water Line (NMWL).

  • Dissolved organic carbon loss from Yedoma permafrost amplified by ice wedge thaw

    Peer Reviewed Literature
    Water Isotope Analyzers

    Pleistocene Yedoma permafrost contains nearly a third of all organic matter (OM) stored in circum-arctic permafrost and is characterized by the presence of massive ice wedges. Due to its rapid formation by sediment accumulation and subsequent frozen storage, Yedoma OM is relatively well preserved and highly biologically available (biolabile) upon thaw. A better understanding of the processes regulating Yedoma degradation is important to improve estimates of the response and magnitude of permafrost carbon feedbacks to climate warming.

  • Quantification of long-term wastewater fluxes at the surface water/groundwater-interface: An integrative model perspective using stable isotopes and acesulfame

    Peer Reviewed Literature
    Water Isotope Analyzers

    The suitability of acesulfame to trace wastewater-related surface water fluxes from streams into the hyporheic and riparian zones over long-term periods was investigated. The transport behavior of acesulfame was compared with the transport of water stable isotopes (δ18O or δ2H). A calibrated model based on a joint inversion of temperature, acesulfame, and piezometric pressure heads was employed in a model validation using data sets of acesulfame and water stable isotopes collected over 5 months in a stream and groundwater.

  • Characterizing moisture exchange between the Hawaiian convective boundary layer and free troposphere using stable isotopes in water

    Peer Reviewed Literature
    Water Isotope Analyzers

    The subtropical convective boundary layer (CBL) plays a critical role in climate by regulating the vertical exchange of moisture, energy, trace gases, and pollutants between the ocean surface and free troposphere. Yet bulk features of this exchange are poorly constrained in climate models. To improve our understanding of moisture transport between the boundary layer and free troposphere, paired measurements of water vapor mixing ratio and the stable isotope ratio 18O/16O are used to evaluate moist convective mixing and entrainment processes near the Big Island of Hawai′i.

  • Ice-vapor equilibrium fractionation factor of hydrogen and oxygen isotopes: Experimental investigations and implications for stable water isotope studies

    Peer Reviewed Literature
    Water Isotope Analyzers

    RATIONALE

    The equilibrium fractionation factors govern the relative change in the isotopic composition during phase transitions of water. The commonly used results, which were published more than 40 years ago, are limited to a minimum temperature of –33°C. This limits the reliability in cold regions. With recent instrumental developments it is now possible to test the accuracy of the earlier results as well as extend the temperature range.

  • Origin of sulfur and mode of gypsum formation in central Iraqi soils

    Peer Reviewed Literature
    Water Isotope Analyzers

    The δ18O and δD values of gypsum crystallization water together with δ18O and δ34S of sulfates were used as reliable techniques to study source of sulfur and mode of gypsum formation in selected central Iraqi soils. Six representative pedons on different geologic units were studied. The slope of 3.2 for δ18O and δD plot of gypsum crystallization water showed that evaporation was the major process of gypsum deposition in the study area. The mean δ34S value of +17.58 ‰ showed that Cretaceous sea sulfate followed by Tertiary is the source of sulfur in studied soils.

  • A depth-controlled tracer technique measures vertical, horizontal and temporal patterns of water use by trees and grasses in a subtropical savanna

    Peer Reviewed Literature
    Water Isotope Analyzers
    • As described in the two-layer hypothesis, woody plants are often assumed to use deep soils to avoid competition with grasses.
  • Increased stray gas abundance in a subset of drinking water wells near Marcellus shale gas extraction

    Peer Reviewed Literature
    Carbon Isotope Analyzers

    Horizontal drilling and hydraulic fracturing are transforming energy production, but their potential environmental effects remain controversial. We analyzed 141 drinking water wells across the Appalachian Plateaus physiographic province of northeastern Pennsylvania, examining natural gas concentrations and isotopic signatures with proximity to shale gas wells. Methane was detected in 82% of drinking water samples, with average concentrations six times higher for homes <1 km from natural gas wells (P = 0.0006).

  • Geochemical and isotopic variations in shallow groundwater in areas of the Fayetteville Shale development, north-central Arkansas

    Peer Reviewed Literature
    Carbon Isotope Analyzers

    Exploration of unconventional natural gas reservoirs such as impermeable shale basins through the use ofhorizontal drilling and hydraulic fracturing has changed the energy landscape in the USA providing a vastnew energy source. The accelerated production of natural gas has triggered a debate concerning thesafety and possible environmental impacts of these operations. This study investigates one of the criticalaspects of the environmental effects; the possible degradation of water quality in shallow aquifers overlyingproducing shale formations.

  • Interannual variation of water isotopologues at Vostok indicates a contribution from stratospheric water vapor

    Peer Reviewed Literature
    Water Isotope Analyzers

    Combined measurements of water isotopologues of a snow pit at Vostok over the past 60 y reveal a unique signature that cannot be explained only by climatic features as usually done. Comparisons of the data using a general circulation model and a simpler isotopic distillation model reveal a stratospheric signature in the 17O-excess record at Vostok.

  • Quantifying sources of methane using light alkanes in the Los Angeles basin, California

    Peer Reviewed Literature
    Gas Concentration Analyzers

    Methane (CH4), carbon dioxide (CO2), carbon monoxide (CO), and C2–C5 alkanes were measured throughout the Los Angeles (L.A.) basin in May and June 2010. We use these data to show that the emission ratios of CH4/CO and CH4/CO2in the L.A. basin are larger than expected from population-apportioned bottom-up state inventories, consistent with previously published work.

  • Precise and accurate δ13C analysis of rock samples using Flash Combustion–Cavity Ring Down Laser Spectroscopy

    Peer Reviewed Literature
    Carbon Isotope Analyzers

    The ratio of 13C to 12C in marine sedimentary rocks holds important clues to the evolution of the carbon cycle through Earth history. Isotopic analyses are traditionally carried out using isotope ratio mass spectrometry (IRMS), but this technique is labor-intensive, expensive and requires expert know-how.

  • Using cavity ringdown spectroscopy for continuous monitoring of δ13C(CO2) and ƒCO2 in the surface ocean

    Peer Reviewed Literature
    Carbon Isotope Analyzers

    The role of the global surface ocean as a source and sink for atmospheric carbon dioxide and the flux strengths between the ocean and the atmosphere can be quantified by measuring the fugacity of CO2 (ƒCO2) as well as the dissolved inorganic carbon (DIC) concentration and its isotopic composition in surface seawater. In this work, the potential of continuous wave cavity ringdown spectroscopy (cw-CRDS) for autonomous underway measurements of ƒCO2 and the stable carbon isotope ratio of DIC [δ13C(DIC)] is explored.

  • Positive and negative impacts of five Austrian gravel pit lakes on groundwater quality

    Peer Reviewed Literature
    Water Isotope Analyzers

    Groundwater-fed gravel pit lakes (GPLs) affect the biological, organic, and inorganic parameters of inflowing groundwater through combined effects of bank filtration at the inflow, reactions within the lake, and bank filtration at the outflow. GPLs result from wet dredging for sand and gravel and may conflict with groundwater protection programs by removing the protective soil cover and exposing groundwater to the atmosphere.

  • Eemian interglacial reconstructed from a Greenland folded ice core

    Peer Reviewed Literature
    Gas Concentration Analyzers

    Efforts to extract a Greenland ice core with a complete record of the Eemian interglacial (130,000 to 115,000 years ago) have until now been unsuccessful. The response of the Greenland ice sheet to the warmer-than-present climate of the Eemian has thus remained unclear. Here we present the new North Greenland Eemian Ice Drilling (‘NEEM’) ice core and show only a modest ice-sheet response to the strong warming in the early Eemian. We reconstructed the Eemian record from folded ice using globally homogeneous parameters known from dated Greenland and Antarctic ice-core records.

  • Secondary Organic Aerosol Formation from Gasoline Vehicle Emissions in a New Mobile Environmental Reaction Chamber

    Peer Reviewed Literature
    Gas Concentration Analyzers

    We present a new mobile environmental reaction chamber for the simulation of the atmospheric aging of aerosols from different emissions sources without limitation from the instruments or facilities available at any single site. The chamber can be mounted on a trailer for transport to host facilities or for mobile measurements. Photochemistry is simulated using a set of 40 UV lights (total power 4 KW). Characterisation of the emission spectrum of these lights shows that atmospheric photochemistry can be accurately simulated over a range of temperatures from −7–25 °C.

  • Rapid Transformation of Inorganic to Organic and Plant-Available Phosphorous in Soils of a Glacier Forefield

    Peer Reviewed Literature
    Water Isotope Analyzers

    Chemical weathering of rocks or sediments is extremely important for the generation of soils, for the evolution of landscape, and as a main source of inorganic nutrients for plant growth and therefore for life. Temporal trends in weathering mechanisms, plant succession and nutrients availability in cold environments can be successfully studied in soil chronosequences along a glacier forefield. In the present paper, this was carried out in the pro-glacial area of Morteratsch. Different forms of phosphorous in the soil, stream and spring water chemistry were investigated.

  • Tracing Atmospheric Nitrate in Groundwater Using Triple Oxygen Isotopes: Evaluation Based on Bottled Drinking Water

    Peer Reviewed Literature
    Water Isotope Analyzers

    The stable isotopic compositions of nitrate dissolved in 49 types of bottled drinkingwater collected worldwide were determined, to trace the fate of atmospheric nitrate(NO−3 atm) that had been deposited into subaerial ecosystems, using the17O anomalies(∆175 O) of nitrate as tracers. The use of bottled water enables collection of groundwaterrecharged at natural, background watersheds. The nitrate in groundwater had small∆17O values ranging from −0.2 ‰ to +4.5 ‰ (n = 49).

  • Mixing of Rhone River Water in Lake Geneva (Switzerland-France) Inferred from Stable Hydrogen and Oxygen Isotope Profiles

    Peer Reviewed Literature
    Water Isotope Analyzers

    Depth profiles were sampled at different locations throughout Lake Geneva on a monthly and seasonal basis over the course of two years and analyzed for their stable hydrogen and oxygen isotope compositions. The isotopic composition indicates an isotopic stratification in the metalimnion during summer and fall. This is related to mixing of Rhône River water, which in summer is dominated by snow and glacier melt waters, and lake water, with the latter having a homogenous isotopic composition.

  • Direct Determination of δ(D) and δ(18O) in Water Samples Using Cavity Ring Down Spectrometry: Application to bottled mineral water

    Peer Reviewed Literature
    Water Isotope Analyzers

    The repeatability, reproducibility and accuracy of the direct measurement of δ(D) and δ(18O) isotopes inwater samples were evaluated using Cavity Ring-Down Spectrometry, and values comparable with the Isotopic Ratio Mass Spectrometry were obtained. Memory effect correction was negligible after five successive injections, and the time for each sample analysis was approximately 70 minutes. Application of the method toBrazilian bottled mineral water has shown that it is possible to trace the origin of the water to at least thestate level within Brazilian geographical regions.

  • A Comparison of in-situ Aircraft Measurements of Carbon Dioxide to GOSAT Data Measured Over Railroad Valley Playa, Nevada, USA

    Peer Reviewed Literature
    Gas Concentration Analyzers

     In this paper we report vertical profiles of CO2 measured with a cavity ring-down spectrometer (CRDS, Picarro, Inc., 2301-m) on a research aircraft from near ground level to 8 km above mean sea level (a.m.s.l.). The airborne platform employed in this study is an Alpha Jet aircraft operated from NASA Ames Research Center. Flights were undertaken to Railroad Valley, Nevada, USA, to coincide with overpasses of the Greenhouse Gases Observing Satellite (GOSAT).

  • Extreme Short-Term Stable Isotope Variability Revealed by Continuous Rainwater Analysis

    Peer Reviewed Literature
    Water Isotope Analyzers

    Continuous real-time analysis, at 30 sec intervals, of precipitation at an Australian tropical location revealed extreme and rapidly changing δ18O and δD values related to variations in moisture source areas, transport paths and precipitation histories. The range of δ18O (−19.6 to +2.6 ‰) and δD (−140 to +13 ‰) values from 5948 measurements of nine rain events over 15 days during an 8 month period at a single location was comparable to the range measured in 1532 monthly samples from all seven Australian GNIP stations from 1962–2002.

  • Hydrogeochemical and isotopic evidence for trans-formational flow in a sedimentary basin: implications for CO2 storage

    Peer Reviewed Literature
    Water Isotope Analyzers

    Deep saline aquifers are considered as the most promising option for geologic disposal of CO2. One of the main concerns, however, is the integrity of the caprocks between and above the storage formations. Here, a hydrogeochemical and isotopic investigation is presented, using ionic chemistry, stable isotopes (δ18O, δ2H and 87Sr/86Sr) and radiocarbon dating, on five saline aquifers on a regional scale, namely: Neogene Minghuazhen, Guantao, Ordivician, Cambrian and Precambrian, all found in the Bohai Bay Basin in North China.

  • Accurate measurements of carbon monoxide in humid air using the cavity ring-down spectroscopy (CRDS) technique

    Peer Reviewed Literature
    Gas Concentration Analyzers

    Accurate measurements of carbon monoxide (CO) in humid air have been made usingthe cavity ring-down spectroscopy (CRDS) technique. The measurements of CO molefractions are determined from the strength of its spectral absorption in the near infraredregion (∼ 1.57 µm) after removing interferences from adjacent carbon dioxide (CO25 )and water vapor (H2O) absorption lines. Water correction functions that account forthe dilution and pressure-broadening effects as well as absorption line interferencesfrom adjacent CO2 and H2O lines have been derived for CO2 mole fractions between360–390 ppm.

  • Evaluation of a Cavity Ring-Down Spectrometer for In-Situ Observations of 13CO2

    Peer Reviewed Literature
    Carbon Isotope Analyzers

    With the emergence of wide-spread application of cavity ring-down spectrometers (CRDS) to monitor δ13C in atmospheric CO2 there is a growing need to ensure well calibrated measurements. We characterized a cavity ring-down spectrometer system used for continuous in-situ monitoring of atmospheric 13CO2. We found no concentration dependency of the δ13C ratio within the range of 303–437 ppm.