Water vapor δ<sup>2</sup>H and δ<sup>18</sup>O measurements using off-axis integrated cavity output spectroscopy
We present a detailed assessment of a commercially available water vapor isotope analyzer (WVIA, Los Gatos Research, Inc.) for simultaneous in-situ measurements of δ<sup>2</sup>H and δ<sup>18</sup>O in water vapor. This method, based on off-axis integrated...
Main Authors: | , |
---|---|
Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2010-01-01
|
Series: | Atmospheric Measurement Techniques |
Online Access: | http://www.atmos-meas-tech.net/3/67/2010/amt-3-67-2010.pdf |
id |
doaj-f3a1c143406e4810a3b4e52823a13606 |
---|---|
record_format |
Article |
spelling |
doaj-f3a1c143406e4810a3b4e52823a136062020-11-24T23:49:56ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482010-01-0131677710.5194/amt-3-67-2010Water vapor δ<sup>2</sup>H and δ<sup>18</sup>O measurements using off-axis integrated cavity output spectroscopyP. Sturm0A. Knohl1Institute of Plant, Animal and Agroecosystem Sciences, ETH Zürich, Universitätsstrasse 2, 8092 Zürich, SwitzerlandInstitute of Plant, Animal and Agroecosystem Sciences, ETH Zürich, Universitätsstrasse 2, 8092 Zürich, SwitzerlandWe present a detailed assessment of a commercially available water vapor isotope analyzer (WVIA, Los Gatos Research, Inc.) for simultaneous in-situ measurements of δ<sup>2</sup>H and δ<sup>18</sup>O in water vapor. This method, based on off-axis integrated cavity output spectroscopy, is an alternative to the conventional water trap/isotope ratio mass spectrometry (IRMS) techniques. We evaluate the analyzer in terms of precision, memory effects, concentration dependence, temperature sensitivity and long-term stability. A calibration system based on a droplet generator is used to characterize the performance and to calibrate the analyzer. Our results show that the precision at an averaging time of 15 s is 0.16‰ for δ<sup>2</sup>H and 0.08‰ for δ<sup>18</sup>O. The isotope ratios are strongly dependent on the water mixing ratio of the air. Taking into account this concentration dependence as well as the temperature sensitivity of the instrument we obtained a long-term stability of the water isotope measurements of 0.38‰ for δ<sup>2</sup>H and 0.25‰ for δ<sup>18</sup>O. The accuracy of the WVIA was further assessed by comparative measurements using IRMS and a dew point generator indicating a linear response in isotopic composition and H<sub>2</sub>O concentrations. The WVIA combined with a calibration system provides accurate high resolution water vapor isotope measurements and opens new possibilities for hydrological and ecological applications.http://www.atmos-meas-tech.net/3/67/2010/amt-3-67-2010.pdf |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
P. Sturm A. Knohl |
spellingShingle |
P. Sturm A. Knohl Water vapor δ<sup>2</sup>H and δ<sup>18</sup>O measurements using off-axis integrated cavity output spectroscopy Atmospheric Measurement Techniques |
author_facet |
P. Sturm A. Knohl |
author_sort |
P. Sturm |
title |
Water vapor δ<sup>2</sup>H and δ<sup>18</sup>O measurements using off-axis integrated cavity output spectroscopy |
title_short |
Water vapor δ<sup>2</sup>H and δ<sup>18</sup>O measurements using off-axis integrated cavity output spectroscopy |
title_full |
Water vapor δ<sup>2</sup>H and δ<sup>18</sup>O measurements using off-axis integrated cavity output spectroscopy |
title_fullStr |
Water vapor δ<sup>2</sup>H and δ<sup>18</sup>O measurements using off-axis integrated cavity output spectroscopy |
title_full_unstemmed |
Water vapor δ<sup>2</sup>H and δ<sup>18</sup>O measurements using off-axis integrated cavity output spectroscopy |
title_sort |
water vapor δ<sup>2</sup>h and δ<sup>18</sup>o measurements using off-axis integrated cavity output spectroscopy |
publisher |
Copernicus Publications |
series |
Atmospheric Measurement Techniques |
issn |
1867-1381 1867-8548 |
publishDate |
2010-01-01 |
description |
We present a detailed assessment of a commercially available water vapor
isotope analyzer (WVIA, Los Gatos Research, Inc.) for simultaneous in-situ
measurements of δ<sup>2</sup>H and δ<sup>18</sup>O in water vapor. This method, based on off-axis
integrated cavity output spectroscopy, is an alternative to the conventional
water trap/isotope ratio mass spectrometry (IRMS) techniques. We evaluate the
analyzer in terms of precision, memory effects, concentration dependence,
temperature sensitivity and long-term stability. A calibration system based
on a droplet generator is used to characterize the performance and to
calibrate the analyzer. Our results show that the precision at an averaging
time of 15 s is 0.16‰ for δ<sup>2</sup>H and 0.08‰ for δ<sup>18</sup>O. The isotope
ratios are strongly dependent on the water mixing ratio of the air. Taking
into account this concentration dependence as well as the temperature
sensitivity of the instrument we obtained a long-term stability of the water
isotope measurements of 0.38‰ for δ<sup>2</sup>H and 0.25‰ for δ<sup>18</sup>O. The
accuracy of the WVIA was further assessed by comparative measurements using
IRMS and a dew point generator indicating a linear response in isotopic
composition and H<sub>2</sub>O concentrations. The WVIA combined with a calibration
system provides accurate high resolution water vapor isotope measurements and
opens new possibilities for hydrological and ecological applications. |
url |
http://www.atmos-meas-tech.net/3/67/2010/amt-3-67-2010.pdf |
work_keys_str_mv |
AT psturm watervapordeltasup2suphanddeltasup18supomeasurementsusingoffaxisintegratedcavityoutputspectroscopy AT aknohl watervapordeltasup2suphanddeltasup18supomeasurementsusingoffaxisintegratedcavityoutputspectroscopy |
_version_ |
1725480760170774528 |