Greifswald 2024 – scientific programme

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UP: Fachverband Umweltphysik

UP 3: Remote Sensing

UP 3.4: Talk

Tuesday, February 27, 2024, 11:45–12:00, ELP 6: HS 4

Portable ground-based scattered sunlight spectrometer for carbon dioxide and methane measurements — •Lukas Weis¹, Benedikt Löw¹, Ralph Kleinschek¹, Tobias Schmitt¹, Frank Hase², and André Butz¹ — ¹Institute of Environmental Physics, Heidelberg University, Germany — ²Institute for Meteorology and Climate Research, Karlsruhe Institute of Technology, Germany

As atmospheric greenhouse gases continue to increase, there is a strong interest in understanding their sources and sinks. Quantifying urban emissions is vital to mitigating human-induced climate change. Our ground-based ’reflected sunlight’ approach offers sensitivity to horizontal greenhouse gas distributions across kilometers, bridging the gap between localized in-situ and regional total column measurements.

We’ve adapted a portable EM27/SUN Fourier transform spectrometer (EM27/SCA) for carbon dioxide (CO₂) and methane (CH₄) retrieval from ground-scattered sunlight within the NIR spectral range. Deployed in an elevated position the EM27/SCA points into a source region along a multi-kilometer horizontal slant path. In 2022 the prototype demonstrated good agreement with CLARS-FTS during side-by-side measurements overlooking the Los Angeles Basin in California, USA.

We present results from this campaign and ongoing work on our second-generation instrument. The most notable improvement is a modular tracking system with optical fiber coupling, enhancing both flexibility and field of view homogenization to reduce the impact of target inhomogeneity on retrievals.

Keywords: Remote Sensing; Fourier Transform Spectroscopy; urban emissions; greenhouse gases; modular tracking system