Novel Approaches for Monitoring of Water Vapor Isotope Ratios: Plants, Lasers and Satellites

Helliker, Brent R.; Noone, David

doi:10.1007/978-90-481-3354-3_4

Cited by 18 publications

(17 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Stable isotopes have been less extensively measured in water vapour than in the liquid phase, mainly because such measurements have been very laborious and error-prone until recently (Helliker and Noone, 2010), involving cryogenic trapping with vacuum flasks (e.g. Yakir and Wang, 1996;Gat et al, 2003;Yepez et al, 2003;Strong et al, 2007) or collection with molecular sieves (Han et al, 2006) followed by isotope ratio mass spectrometric (IRMS) analysis.…”

Section: F Aemisegger Et Al: Characterisation Of Water Vapour Isotomentioning

confidence: 99%

Measuring variations of δ18O and δ2H in atmospheric water vapour using two commercial laser-based spectrometers: an instrument characterisation study

et al. 2012

View full text Add to dashboard Cite

Abstract. Variations of stable water isotopes in water vapourhave become measurable at a measurement frequency of about 1 Hz in recent years using novel laser spectroscopic techniques. This enables us to perform continuous measurements for process-based investigations of the atmospheric water cycle at the time scales relevant for synoptic and mesoscale meteorology. An important prerequisite for the interpretation of data from automated field measurements lasting for several weeks or months is a detailed knowledge about instrument properties and the sources of measurement uncertainty. We present here a comprehensive characterisation and comparison study of two commercial laser spectroscopic systems based on cavity ring-down spectroscopy (Picarro) and off-axis integrated cavity output spectroscopy (Los Gatos Research). The uncertainty components of the measurements were first assessed in laboratory experiments, focussing on the effects of (i) water vapour mixing ratio, (ii) measurement stability, (iii) uncertainties due to calibration and (iv) response times of the isotope measurements due to adsorption-desorption processes on the tubing and measurement cavity walls. Based on the experience from our laboratory experiments, we set up a one-week field campaign for comparing measurements of the ambient isotope signals from the two laser spectroscopic systems. The optimal calibration strategy determined for both instruments was applied as well as the correction functions for water vapour mixing ratio effects. The root mean square difference between the isotope signals from the two instruments during the field deployment was 2.3 ‰ for δ 2 H, 0.5 ‰ for δ 18 O and 3.1 ‰ for deuterium excess. These uncertainty estimates from field measurements compare well to those found in the laboratory experiments. The present quality of measurements from laser spectroscopic instruments combined with a calibration system opens new possibilities for investigating the atmospheric water cycle and the land-atmosphere moisture fluxes.

show abstract

Section: F Aemisegger Et Al: Characterisation Of Water Vapour Isotomentioning

confidence: 99%

Measuring variations of δ18O and δ2H in atmospheric water vapour using two commercial laser-based spectrometers: an instrument characterisation study

et al. 2012

View full text Add to dashboard Cite

show abstract

“…This particularly holds with regard to complex and heterogeneous processes, such as infiltration and shallow subsurface flow in the vadose zone subject to strong gradients and fluxes of energy and matter, demanding stable isotope data with high spatial and temporal resolution to complement traditional observations. Instead, a major limitation to the extent and scope of stable isotope applications was imposed by the available techniques for sampling and analysis (e.g., Kerstel and Meijer, 2005;Helliker and Noone, 2010;Munksgaard et al, 2011). Conventionally, measurement of water stable isotopic composition was relatively labor-, time-, and cost-intensive and constrained to laboratory-bound analysis of previously collected and processed discrete samples based on gas source isotope ratio mass spectrometry (IRMS) (Horita and Kendall, 2004).…”

Section: T H M Volkmann and M Weiler: Pore Water Stable Isotopes mentioning

confidence: 99%

“…In recent years, major advances in analyzing techniques have come with the advent of commercially available, portable, and field-deployable laser spectroscopic instruments for isotopic analysis of water vapor (see reviews by Kerstel and Meijer, 2005;Kerstel and Gianfrani, 2008;Helliker and Noone, 2010). Available instruments based on, for instance, wavelength-scanned cavity ring-down spectroscopy (WS-CRDS) allow for direct simultaneous highfrequency measurements of oxygen and hydrogen stable isotopic composition of water vapor at a precision and accuracy approaching that of IRMS (Berden et al, 2000;Crosson, 2008;Kerstel and Gianfrani, 2008;Gupta et al, 2009).…”

Section: T H M Volkmann and M Weiler: Pore Water Stable Isotopes mentioning

confidence: 99%

Continual in situ monitoring of pore water stable isotopes in the subsurface

Volkmann

Weiler

2014

Hydrol. Earth Syst. Sci.

113

129

View full text Add to dashboard Cite

Abstract. Stable isotope signatures provide an integral fingerprint of origin, flow paths, transport processes, and residence times of water in the environment. However, the full potential of stable isotopes to quantitatively characterize subsurface water dynamics is yet unfolded due to the difficulty in obtaining extensive, detailed, and repeated measurements of pore water in the unsaturated and saturated zone. This paper presents a functional and cost-efficient system for nondestructive continual in situ monitoring of pore water stable isotope signatures with high resolution. Automatic controllable valve arrays are used to continuously extract diluted water vapor in soil air via a branching network of small microporous probes into a commercial laser-based isotope analyzer. Normalized liquid-phase isotope signatures are then obtained based on a specific on-site calibration approach along with basic corrections for instrument bias and temperature dependent isotopic fractionation. The system was applied to sample depth profiles on three experimental plots with varied vegetation cover in southwest Germany. Two methods (i.e., based on advective versus diffusive vapor extraction) and two modes of sampling (i.e., using multiple permanently installed probes versus a single repeatedly inserted probe) were tested and compared. The results show that the isotope distribution along natural profiles could be resolved with sufficiently high accuracy and precision at sampling intervals of less than four minutes. The presented in situ approaches may thereby be used interchangeably with each other and with concurrent laboratory-based direct equilibration measurements of destructively collected samples. It is thus found that the introduced sampling techniques provide powerful tools towards a detailed quantitative understanding of dynamic and heterogeneous shallow subsurface and vadose zone processes.

show abstract

“…Laser-based spectroscopic analyzers, being easily deployable for field measurements, could sample continuously and, thus, offer novel potential for improved measurement density. In addition, its precision and accuracy are almost comparable to that of the laboratory-based IRMS [45]. For example, new gas analyzers based on off-axis integrated cavity output spectroscopy (OA-ICOS) lasers are attractive instruments for long-term shipborne isotope measurements [46].…”

Section: Long-term Isotopicmentioning

confidence: 99%

“…High-quality isotope measurements over the oceans would be extremely valuable for physical understanding and model developments and validation. As Helliker and Noone [45] put it, successful deployment of this new technology could potentially "revolutionize water isotope science. "…”

Section: Long-term Isotopicmentioning

confidence: 99%

A Review of Water Isotopes in Atmospheric General Circulation Models: Recent Advances and Future Prospects

2014

International Journal of Atmospheric Sciences

View full text Add to dashboard Cite

Stable water isotopologues, mainly1 H 2 O, 1 H 2 HO (HDO), and 1 H 2 18 O, are useful tracers for processes in the global hydrological cycle. The incorporation of water isotopes into Atmospheric General Circulation Models (AGCMs) since 1984 has helped scientists gain substantial new insights into our present and past climate. In recent years, there have been several significant advances in water isotopes modeling in AGCMs. This paper reviews and synthesizes key advances accomplished in modeling (1) surface evaporation, (2) condensation, (3) supersaturation, (4) postcondensation processes, (5) vertical distribution of water isotopes, and (6) spatial 18 O-temperature slope and utilizing (1) spectral nudging technique, (2) higher model resolutions, and (3) coupled atmosphereocean models. It also reviews model validation through comparisons of model outputs and ground-based and spaceborne measurements. In the end, it identifies knowledge gaps and discusses future prospects of modeling and model validation.

show abstract

Novel Approaches for Monitoring of Water Vapor Isotope Ratios: Plants, Lasers and Satellites

Cited by 18 publications

References 44 publications

Measuring variations of δ<sup>18</sup>O and δ<sup>2</sup>H in atmospheric water vapour using two commercial laser-based spectrometers: an instrument characterisation study

Measuring variations of δ<sup>18</sup>O and δ<sup>2</sup>H in atmospheric water vapour using two commercial laser-based spectrometers: an instrument characterisation study

Continual in situ monitoring of pore water stable isotopes in the subsurface

A Review of Water Isotopes in Atmospheric General Circulation Models: Recent Advances and Future Prospects

Contact Info

Product

Resources

About

Novel Approaches for Monitoring of Water Vapor Isotope Ratios: Plants, Lasers and Satellites

Cited by 18 publications

References 44 publications

Measuring variations of δ&lt;sup&gt;18&lt;/sup&gt;O and δ&lt;sup&gt;2&lt;/sup&gt;H in atmospheric water vapour using two commercial laser-based spectrometers: an instrument characterisation study

Measuring variations of δ&lt;sup&gt;18&lt;/sup&gt;O and δ&lt;sup&gt;2&lt;/sup&gt;H in atmospheric water vapour using two commercial laser-based spectrometers: an instrument characterisation study

Continual in situ monitoring of pore water stable isotopes in the subsurface

A Review of Water Isotopes in Atmospheric General Circulation Models: Recent Advances and Future Prospects

Contact Info

Product

Resources

About

Measuring variations of δ<sup>18</sup>O and δ<sup>2</sup>H in atmospheric water vapour using two commercial laser-based spectrometers: an instrument characterisation study

Measuring variations of δ<sup>18</sup>O and δ<sup>2</sup>H in atmospheric water vapour using two commercial laser-based spectrometers: an instrument characterisation study