Marvin Knapp and colleagues demonstrate how to image carbon dioxide exhaust plumes from powerplants and other localized sources using a hyperspectral camera. The instrument collects skylight in the shortwave infrared spectral range. The absorption fingerprint of carbon dioxide is then used to determine the column enhancements due to the exhaust plumes. Knapp et al. combine radiative transfer modelling with imaging processing techniques for the spectral analysis and they employ Gaussian plume modelling to derive average emission rates with roughly hourly resolution. Correlating the known powerplant emission rates provided by the facility operators with the estimated ones shows that the spectroscopic technique is accurate to within 20%. Heterogeneous illumination conditions such as under cloudy skies pose particular challenges but typically such cases can be filtered reliably.
Highlight paper in Atmospheric Measurement Techniques: Knapp, M., Kleinschek, R., Vardag, S. N., Külheim, F., Haveresch, H., Sindram, M., Siegel, T., Burger, B., and Butz, A.: Quantitative imaging of carbon dioxide plumes using a ground-based shortwave infrared spectral camera, Atmos. Meas. Tech., 17, 2257–2275, https://doi.org/10.5194/amt-17-2257-2024, 2024.