Abstract
Abstract. We demonstrate the capability of the Sentinel-2 MultiSpectral Instrument (MSI) to detect and quantify anomalously large methane point sources with fine pixel resolution (20 m) and rapid revisit rates (2–5 d). We present three methane column retrieval methods that use shortwave infrared (SWIR) measurements from MSI spectral bands 11 (∼ 1560–1660 nm) and 12 (∼ 2090–2290 nm) to detect atmospheric methane plumes. The most successful is the multi-band–multi-pass (MBMP) method, which uses a combination of the two bands and a non-plume reference observation to retrieve methane columns. The MBMP method can quantify point sources down to about 3 t h−1 with a precision of ∼ 30 %–90 % (1σ) over favorable (quasi-homogeneous) surfaces. We applied our methods to perform high-frequency monitoring of strong methane point source plumes from a well-pad device in the Hassi Messaoud oil field of Algeria (October 2019 to August 2020, observed every 2.5 d) and from a compressor station in the Korpezhe oil and gas field of Turkmenistan (August 2015 to November 2020, observed every 5 d). The Algerian source was detected in 93 % of cloud-free scenes, with source rates ranging from 2.6 to 51.9 t h−1 (averaging 9.3 t h−1) until it was shut down by a flare lit in August 2020. The Turkmen source was detected in 40 % of cloud-free scenes, with variable intermittency and a 9-month shutdown period in March–December 2019 before it resumed; source rates ranged from 3.5 to 92.9 t h−1 (averaging 20.5 t h−1). Our source-rate retrievals for the Korpezhe point source are in close agreement with GHGSat-D satellite observations for February 2018 to January 2019, but provide much higher observation density. Our methods can be readily applied to other satellite instruments with coarse SWIR spectral bands, such as Landsat-7 and Landsat-8. High-frequency satellite-based detection of anomalous methane point sources as demonstrated here could enable prompt corrective action to help reduce global methane emissions.
Highlights
Methane is a potent greenhouse gas that is responsible for roughly one quarter of the climate warming experienced since preindustrial times (IPCC, 2013)
We present case studies illustrating high-frequency monitoring of methane emissions from venting at two oil and gas facilities in the Hassi Messaoud oil field of Algeria and the Korpezhe oil and gas field of Turkmenistan, inferring source rates for more than 160 methane plumes observed by Sentinel-2 at these sites between 2015 and 2020
Water vapor and CO2 are generally not co-emitted with methane from large point sources, so their concentrations can be assumed uniform across a given scene, and we show in Sect. 3.1 that they have negligible effects on the methane point source retrieval
Summary
Methane is a potent greenhouse gas that is responsible for roughly one quarter of the climate warming experienced since preindustrial times (IPCC, 2013). Hyperspectral imaging spectrometers designed to observe land surfaces at 1–10 nm spectral resolution with 30 m pixel resolution can detect large methane plumes (Thompson et al, 2016; Cusworth et al, 2019), as was recently demonstrated with the Italian Space Agency’s PRISMA instrument (Cusworth et al, 2021) Revisit times for these targeting instruments are limited by spatial coverage, tasking constraints, and the number of satellites; achieving frequent revisits will require a constellation. This work demonstrates how spaceborne multispectral imaging instruments can facilitate global high-frequency mapping of large methane point sources by combining fine pixel resolution with rapid revisit rates
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
