• Corpus ID: 229363325

Open-path Dual-comb Spectroscopy for Multispecies Trace Gas Detection in the 4.5 {\mu}m to 5 {\mu}m Spectral Region

@inproceedings{Giorgetta2020OpenpathDS,
  title={Open-path Dual-comb Spectroscopy for Multispecies Trace Gas Detection in the 4.5 \{\mu\}m to 5 \{\mu\}m Spectral Region},
  author={Fabrizio Raphael Giorgetta and Jeff Peischl and Daniel I. Herman and Gabriel Ycas and Ian Coddington and Nathan R. Newbury and Kevin C. Cossel},
  year={2020}
}

• F. Giorgetta, J. Peischl, +4 authors K. Cossel
• Published 23 December 2020
• Environmental Science

Open-path dual-comb spectroscopy provides multi-species atmospheric gas concentration measurements with high precision. Here, we extend open-path dual comb spectroscopy to the mid-infrared 5 {\mu}m atmospheric window, enabling atmospheric concentration retrievals of the primary greenhouse gases, N$_2$O, CO$_2$, and H$_2$O as well as the criterion air pollutants O$_3$ and CO across 600 m and 2 km round-trip paths. We demonstrate measurements over a five-day period at two-minute temporal resolution with 80% uptime. The achieved precision is sufficient to resolve the atmospheric concentration variations of the multiple gas species; retrieved dry mixing ratios of CO and N$_2$O are in good agreement with a co-located point sensor. In addition, the retrieved ratio of excess CO vs CO$_2$ agrees with similar urban studies but disagrees with the US National Emission Inventory by a factor of 3. Our retrieved ratio of excess N$_2$O vs CO$_2$ exhibits a plume-dependent value, indicating the variability of sources of the greenhouse gas N$_2$O.