# Towards Carbon Dioxide imaging using Fabry-Pérot interferometer correlation spectroscopy

Moritz Sindram, Jonas Kuhn, Ralph Kleinschek, Christopher Fuchs, Marvin

Knapp, Benedikt Löw, Alexander Nies, Tobias Schmitt, André Butz

► To cite this version:

Moritz Sindram, Jonas Kuhn, Ralph Kleinschek, Christopher Fuchs, Marvin Knapp, et al. To-wards Carbon Dioxide imaging using Fabry-Pérot interferometer correlation spectroscopy. European Geosciences Union General Assembly 2024 (EGU24), Apr 2024, Vienna, Austria. 10.5194/egusphere-egu24-5711. insu-04652306

HAL Id: insu-04652306

https://insu.hal.science/insu-04652306v1

Submitted on 18 Jul 2024

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# Towards Carbon Dioxide imaging using Fabry-Pérot interferometer correlation spectroscopy

Moritz Sindram<fnref n="1" />, Jonas Kuhn<fnref n="2" />, Ralph Kleinschek<fnref n="1" />, Christopher Fuchs<fnref n="3" />, Marvin Knapp<fnref n="1" />, Benedikt Löw<fnref n="1" />, Alexander Nies<fnref n="4" />, Tobias Schmitt<fnref n="1" />, and André Butz<fnref n="1" />

Carbon dioxide (CO₂) emissions are the major driver of anthropogenic climate change. While strong point sources contribute significantly to overall emissions, their source strength is not always well quantified by bottom-up estimates or in situ measurements. Passive remote sensing of CO₂ emissions could provide a simple tool to substantially refine source strength estimates. However, current approaches from ground-based to space-borne platforms only suit exceptionally strong emitters.

We propose a ground-based CO₂ imaging technique based on Fabry-Perot interferometer (FPI) correlation spectroscopy. The free spectral range (FSR) of an FPI is matched to the spectral separation of individual rovibrational absorption lines of the CO₂ 1.57 µm absorption band. This allows to compare the radiance of sky-scattered sunlight between “online” and “offline” wavelengths, i.e., the FPI transmission spectrum correlating and anti-correlating with the CO₂ absorption lines, respectively. The advantage of a high FPI light throughput enables imaging measurements of the CO₂ column density with a resolving power of 18,000.

Instrument simulations based on available optics suggest an integration time of approximately 10 seconds to record a CO₂ plume image with 300 by 300 pixels of a medium-sized power plant (7 Mt CO₂/yr). This is about two orders of magnitude faster compared to grating-based imaging spectrometers. For recording the emission plume of a passively degassing volcano at the same spatial resolution integration times are on the order of ten minutes. Additionally, we present ongoing work on developing a prototype instrument to validate the feasibility of this CO₂ imaging technique.

<footnote n="1">¹Institute of Environmental Physics, Heidelberg University, Heidelberg, Germany (moritz.sindram@iup.uni-heidelberg.de)</footnote>

<footnote n="2">²Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA, USA</footnote>

<footnote n="3">³Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland</footnote>

<footnote n="4">⁴Laboratoire de Physique et de Chimie de l'Environnement et de l'Espace, CNRS/University Orleans, Orleans, France</footnote>