Journal cover Journal topic
Atmospheric Measurement Techniques An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

IF value: 3.668
IF3.668
IF 5-year value: 3.707
IF 5-year
3.707
CiteScore value: 6.3
CiteScore
6.3
SNIP value: 1.383
SNIP1.383
IPP value: 3.75
IPP3.75
SJR value: 1.525
SJR1.525
Scimago H <br class='widget-line-break'>index value: 77
Scimago H
index
77
h5-index value: 49
h5-index49
Volume 6, issue 6
Atmos. Meas. Tech., 6, 1491–1501, 2013
https://doi.org/10.5194/amt-6-1491-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
Atmos. Meas. Tech., 6, 1491–1501, 2013
https://doi.org/10.5194/amt-6-1491-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 05 Jun 2013

Research article | 05 Jun 2013

Evaluating calibration strategies for isotope ratio infrared spectroscopy for atmospheric 13CO2 / 12CO2 measurement

X.-F. Wen1, Y. Meng1, X.-Y. Zhang1, X.-M. Sun1, and X. Lee2,3 X.-F. Wen et al.
  • 1Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
  • 2Yale-NUIST Center on Atmospheric Environment, Nanjing University of Information Science & Technology, Nanjing 210044, China
  • 3School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut 06511, USA

Abstract. Isotope ratio infrared spectroscopy (IRIS) provides an in situ technique for measuring δ13C in atmospheric CO2. A number of methods have been proposed for calibrating the IRIS measurements, but few studies have systematically evaluated their accuracy for atmospheric applications. In this study, we carried out laboratory and ambient measurements with two commercial IRIS analyzers and compared the accuracy of four calibration strategies. We found that calibration based on the 12C and 13C mixing ratios (Bowling et al., 2003) and on linear interpolation of the measured delta using the mixing ratio of the major isotopologue (Lee et al., 2005) yielded accuracy better than 0.06‰. Over a 7-day atmospheric measurement in Beijing, the two analyzers agreed to within −0.02 ± 0.18‰ after proper calibration. However, even after calibration the difference between the two analyzers showed a slight correlation with concentration, and this concentration dependence propagated through the Keeling analysis, resulting in a much larger difference of 2.44‰ for the Keeling intercept. The high sensitivity of the Keeling analysis to the concentration dependence underscores the challenge of IRIS for atmospheric research.

Publications Copernicus
Download
Citation