First continuous shipboard δ18O and δD measurements in sea water by diffusion sampling—cavity ring-down spectrometry

Munksgaard, Niels C.; Wurster, Christopher M.; Bass, Adrian M.; Zagorskis, Irena; Bird, Michael I.

doi:10.1007/s10311-012-0371-5

Cited by 29 publications

(29 citation statements)

References 27 publications

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“…Second, the L2120-i has been widely used to measure δ 18 O-H 2 O and δ 2 H-H 2 O values in situations where background variation could be relevant to the calibration procedures and/or the fundamental measurements. Examples include applications to measurements of liquid water in precipitation (Munksgaard et al, 2011), plant water (West et al, 2011), soil water (Herbstritt et al, 2012), and seawater (Munksgaard et al, 2012), as well as water vapor in the terrestrial boundary layer (Berkelhammer et al, 2013) and marine boundary layer (Steen-Larsen et al, 2014). Third, it has recently been shown that the L2120-i measurements are highly sensitive to the N 2 / O 2 , N 2 / CO 2 , and CO 2 / O 2 composition of the background gas and that the magnitude of the sensitivity is relevant to many observational and experimental situations (Gralher et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Effects of variation in background mixing ratios of N2, O2, and Ar on the measurement of δ18O–H2O and δ2H–H2O values by cavity ring-down spectroscopy

Johnson

Rella

2017

Atmos. Meas. Tech.

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Abstract. Cavity ring-down spectrometers have generally been designed to operate under conditions in which the background gas has a constant composition. However, there are a number of observational and experimental situations of interest in which the background gas has a variable composition. In this study, we examine the effect of background gas composition on a cavity ring-down spectrometer that measures δ 18 O-H 2 O and δ 2 H-H 2 O values based on the amplitude of water isotopologue absorption features around 7184 cm −1 (L2120-i, Picarro, Inc.). For background mixtures balanced with N 2 , the apparent δ 18 O values deviate from true values by −0.50 ± 0.001 ‰ O 2 % −1 and −0.57 ± 0.001 ‰ Ar % −1 , and apparent δ 2 H values deviate from true values by 0.26 ± 0.004 ‰ O 2 % −1 and 0.42 ± 0.004 ‰ Ar % −1 . The artifacts are the result of broadening, narrowing, and shifting of both the target absorption lines and strong neighboring lines. While the background-induced isotopic artifacts can largely be corrected with simple empirical or semimechanistic models, neither type of model is capable of completely correcting the isotopic artifacts to within the inherent instrument precision. The development of strategies for dynamically detecting and accommodating background variation in N 2 , O 2 , and/or Ar would facilitate the application of cavity ring-down spectrometers to a new class of observations and experiments.

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Section: Introductionmentioning

confidence: 99%

Effects of variation in background mixing ratios of N2, O2, and Ar on the measurement of δ18O–H2O and δ2H–H2O values by cavity ring-down spectroscopy

Johnson

Rella

2017

Atmos. Meas. Tech.

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“…In this study, to analyse the isotopic composition of liquid water, we used a diffusion sampling cell developed by Munksgaard et al (2011) which utilised gas permeable Teflon tubing contained in an air tight, desiccated chamber to extract water vapour from a continuously refreshed water supply (Diffusion Sampling-(DS-) CRDS). This system has successfully been used to delineate carbon sources in storm flow (Bass et al, 2014a), track oceanic water mass boundaries in tropical (Munksgaard et al, 2012b) and polar waters (Bass et al, 2014b) and elucidate precipitation formation processes in a tropical cyclone (Munksgaard et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Continuous monitoring of stream δ¹⁸O and δ²H and stormflow hydrograph separation using laser spectrometry in an agricultural catchment

Tweed

Munksgaard

Marc

et al. 2015

Hydrological Processes

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A portable Wavelength Scanned-Cavity Ring-Down Spectrometer (Picarro L2120) fitted with a diffusion sampler (DS-CRDS) was used for the first time to continuously measure δ 2 H data during a storm event are highlighted from this study. First, they enabled us to separate components of the hydrograph, which was not possible using high temporal resolution electrical conductivity data that represented changes in solute transfers during the storm event rather than physical hydrological processes. The results from the hydrograph separation confirm fast groundwater contribution to the stream, with the first 5 h of increases in stream discharge comprising over 70% pre-event water. Second, the high temporal resolution stream δ 18 O and δ 2 H data allowed us to detect a short-lived reversal in stream isotopic values (δ 18 O increase by 0.4‰ over 9 min), which was observed immediately after the heavy rainfall period. Third, δ18 O values were used to calculate a time lag of 20 min between the physical and chemical stream responses during the storm event. Finally, the hydrograph separation highlights the role of event waters in the runoff transfers of herbicides and nutrients from this heavily cultivated catchment to the Great Barrier Reef.

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“…For example, in the case of salinity, where δ Ow is the proxy and salinity (S) is the 159 target variable, this would take the form δ Ow = αS + b, where the gradient α = ∆δ Ow /∆S. By definition of 160 the linear relationship, the intercept value, b, is an indicator of the freshwater end-member (δ F ), defined as 161 the value of δ Ow when S=0 (Delaygue et al, 2001;LeGrande and Schmidt, 2006;Munksgaard et al, 2012).…”

mentioning

confidence: 99%

“…During the LIG, when no ice sheet changes have been applied, changes in the δ Ow -salinity relationship river discharge (Munksgaard et al, 2012), the isotopic composition of regional precipitation (δ Op ) (Benway 412 and Mix, 2004;LeGrande and Schmidt, 2006;Abe et al, 2009), local evaporation regime (Conroy et al,413 2014), and a mixture of evaporation, precipitation and runoff (Delaygue et al, 2001 …”

mentioning

confidence: 99%

Reconstructing paleosalinity from δ18O: Coupled model simulations of the Last Glacial Maximum, Last Interglacial and Late Holocene

Holloway

Sime

Singarayer³

et al. 2016

Quaternary Science Reviews

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Reconstructions of salinity are used to diagnose changes in the hydrological cycle and ocean circulation.A widely used method of determining past salinity uses oxygen isotope (δ Ow ) residuals after the extraction of the global ice volume and temperature components. This method relies on a constant relationship between δ Ow and salinity throughout time. Here we use the isotope-enabled fully coupled General Circulation Model (GCM) HadCM3 to test the application of spatially and time-independent relationships in the reconstruction of past ocean salinity. Simulations of the Late Holocene (LH), Last Glacial Maximum (LGM), and Last Interglacial (LIG) climates are performed and benchmarked against existing compilations of stable oxygen isotopes in carbonates (δ Oc ), which primarily reflect δ Ow and temperature. We find that HadCM3 produces an accurate representation of the surface ocean δ Oc distribution for the LH and LGM. Our simulations show considerable variability in spatial and temporal δ Ow -salinity relationships. Spatial gradients are generally shallower but within ⇠50 % of the actual simulated LH to LGM and LH to LIG temporal gradients and temporal gradients calculated from multi-decadal variability are generally shallower than both spatial and actual simulated gradients. The largest sources of uncertainty in salinity reconstructions are found to be caused by changes in regional freshwater budgets, ocean circulation, and sea ice regimes. These can cause errors in salinity estimates exceeding 4 psu. Our results suggest that paleosalinity reconstructions in the South Atlantic, Indian and Tropical Pacific Oceans should be most robust, since these regions exhibit relatively constant δ Ow -salinity relationships across spatial and temporal scales. Largest uncertainties will affect North Atlantic and high latitude paleosalinity reconstructions. Finally, the results show that it is difficult to generate reliable salinity estimates for regions of dynamic oceanography, such as the North Atlantic, without additional constraints.

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First continuous shipboard δ18O and δD measurements in sea water by diffusion sampling—cavity ring-down spectrometry

Cited by 29 publications

References 27 publications

Effects of variation in background mixing ratios of N<sub>2</sub>, O<sub>2</sub>, and Ar on the measurement of <i>δ</i><sup>18</sup>O–H<sub>2</sub>O and <i>δ</i><sup>2</sup>H–H<sub>2</sub>O values by cavity ring-down spectroscopy

Effects of variation in background mixing ratios of N<sub>2</sub>, O<sub>2</sub>, and Ar on the measurement of <i>δ</i><sup>18</sup>O–H<sub>2</sub>O and <i>δ</i><sup>2</sup>H–H<sub>2</sub>O values by cavity ring-down spectroscopy

Continuous monitoring of stream δ¹⁸O and δ²H and stormflow hydrograph separation using laser spectrometry in an agricultural catchment

Reconstructing paleosalinity from δ18O: Coupled model simulations of the Last Glacial Maximum, Last Interglacial and Late Holocene

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First continuous shipboard δ18O and δD measurements in sea water by diffusion sampling—cavity ring-down spectrometry

Cited by 29 publications

References 27 publications

Continuous monitoring of stream δ18O and δ2H and stormflow hydrograph separation using laser spectrometry in an agricultural catchment

Reconstructing paleosalinity from δ18O: Coupled model simulations of the Last Glacial Maximum, Last Interglacial and Late Holocene

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Continuous monitoring of stream δ¹⁸O and δ²H and stormflow hydrograph separation using laser spectrometry in an agricultural catchment