Space-based observations of tropospheric ethane map emissions from fossil fuel extraction
Jared F. Brewer, Dylan B. Millet, Kelley C. Wells, Vivienne H. Payne, S. S. Kulawik, Corinne Vigouroux, Karen Cady‐Pereira, Rick Pernak, Minqiang Zhou
Abstract
Ethane is the most abundant non-methane hydrocarbon in the troposphere, where it impacts ozone and reactive nitrogen and is a key tracer used for partitioning emitted methane between anthropogenic and natural sources. However, quantification has been challenged by sparse observations. Here, we present a satellite-based measurement of tropospheric ethane and demonstrate its utility for fossil-fuel source quantification. An ethane spectral signal is detectable from space in Cross-track Infrared Sounder (CrIS) radiances, revealing ethane signatures associated with fires and fossil fuel production. We use machine-learning to convert these signals to ethane abundances and validate the results against surface observations (R2 = 0.66, mean CrIS/surface ratio: 0.65). The CrIS data show that the Permian Basin in Texas and New Mexico exhibits the largest persistent ethane enhancements on the planet, with regional emissions underestimated by seven-fold. Correcting this underestimate reveals Permian ethane emissions that represent at least 4-7% of the global fossil-fuel ethane source. The authors have developed a satellite-based method that detects tropospheric ethane, revealing major sources like fires and fossil fuels. It agrees with ground-based observations and shows Permian Basin emissions of ethane are higher than estimated.