Open-path measurement of stable water isotopologues using mid-infrared dual-comb spectroscopy
<p>We present an open-path mid-infrared dual-comb spectroscopy (DCS) system capable of precise measurement of the stable water isotopologues H<span class="inline-formula"><sub>2</sub></span><span class="inline-formula"><sup>16</sup>...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2023-09-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | https://amt.copernicus.org/articles/16/4053/2023/amt-16-4053-2023.pdf |
| Summary: | <p>We present an open-path mid-infrared dual-comb spectroscopy (DCS) system capable of precise measurement of the stable water isotopologues H<span class="inline-formula"><sub>2</sub></span><span class="inline-formula"><sup>16</sup></span>O and HD<span class="inline-formula"><sup>16</sup></span>O. This system ran in a remote configuration at a rural test site for 3.75 months with 60 % uptime and achieved a precision of <span class="inline-formula"><</span> 2 ‰ on the normalized ratio of H<span class="inline-formula"><sub>2</sub></span><span class="inline-formula"><sup>16</sup></span>O and
HD<span class="inline-formula"><sup>16</sup></span>O (<span class="inline-formula"><i>δ</i></span>D) in 1000 s. Here, we compare the <span class="inline-formula"><i>δ</i></span>D
values from the DCS system to those from the National Ecological Observatory
Network (NEON) isotopologue point sensor network. Over the multi-month
campaign, the mean difference between the DCS <span class="inline-formula"><i>δ</i></span>D values and the NEON <span class="inline-formula"><i>δ</i></span>D values from a similar ecosystem is <span class="inline-formula"><</span> 2 ‰ with a standard deviation of 18 ‰, which demonstrates the inherent accuracy of DCS measurements over a variety of atmospheric conditions. We observe time-varying diurnal profiles and seasonal trends that are mostly correlated between the sites on daily timescales. This observation motivates the development of denser ecological monitoring networks aimed at understanding regional- and synoptic-scale water transport. Precise and accurate open-path measurements using DCS provide new
capabilities for such networks.</p> |
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| ISSN: | 1867-1381 1867-8548 |