Pyra: Automated EM27/SUN Greenhouse Gas Measurement Software

Abstract

The human activity of burning fossil fuels is the driving factor of global warming (Arias et al., 2021). To promote global climate change mitigation policies, a profound greenhouse gases (GHG) observational data basis is required to understand and quantify the sources and sinks of GHG emissions (Arias et al., 2021). Ground-based remote sensing instruments that analyze direct sunlight using, for example, EM27/SUN fourier-transform infrared spectrometers (FTIR) (Gisi et al., 2011) fill the gap between ground-based in situ measurements and space-based measurements by satellites (Hase et al., 2015; Rißmann et al., 2022). Due to its dependency on direct sunlight and clear skies, the EM27/SUN generally requires a trained operator on site. Depending on the weather conditions, the operator needs to manually control the instrument and measurement times. This is time and cost-intensive, in particular, if more than one instrument is involved. However, state-of-the-art EM27/SUN networks consist of up to 6 instruments to estimate the emissions of cities (Che et al., 2022; Dietrich et al., 2021; Hase et al., 2015; Ionov et al., 2021; Jones et al., 2021; Tu et al., 2022; Vogel et al., 2019) or local and regional GHG sources (Chen et al., 2016, 2020; Klappenbach F. et al., 2022; Luther et al., 2022; Toja-Silva et al., 2017; Tu et al., 2020, 2022). These setups generally require at least one operator to operate and closely monitor each instrument. Pyra is an automation software that does not require a trained operator and enables the user to perform EM27/SUN measurements with a workload limited to system monitoring. This also guarantees continuous measurements during weekends, holidays, and at remote locations resulting in an optimized data yield while saving time and human resources. Pyra’s open-source code and documentation will reduce operator training efforts.