Understanding the potential of Sentinel-2 for monitoring methane point emissions

The use of satellite instruments to detect and quantify methane emissions from fossil fuel production activities is highly beneficial to support climate change mitigation. Different hyperspectral and multispectral satellite sensors have recently shown potential to detect and quantify point-source emissions from space. The Sentinel-2 (S2) mission, despite its limited spectral design, supports the detection of large emissions with global coverage and high revisit frequency thanks to coarse spectral coverage of methane absorption lines in the shortwave infrared. Validation of S2 methane retrieval algorithms is instrumental in accelerating the development of a systematic and global monitoring system for methane point sources. Here we develop a benchmarking framework for such validation. We first develop a methodology to generate simulated S2 datasets including methane point-source plumes. These benchmark datasets have been created for scenes in three oil and gas basins (Hassi Messaoud, Algeria; Korpeje, Turkmenistan; Permian Basin, USA) under different scene heterogeneity conditions and for simulated methane plumes with different spatial distributions. We use the simulated methane plumes to validate the retrieval for different flux rate levels and define a minimum detection threshold for each case study. The results suggest that for homogeneous surfaces, the detection limit of the proposed S2 methane retrieval ranges from 1000 kg h&minus;1 to 2000 kg h&minus;1, whereas for areas with large surface heterogeneity, the retrieval can only detect plumes in excess of 5000 kg h&minus;1. The different sources of uncertainty in the flux rate estimates have also been examined. Dominant quantification errors are either wind-related or plume mask-related, depending on the surface type. Uncertainty in wind speed, both in the 10-m wind (U10) and in mapping U10 to the effective wind (Ueff ) driving plume transport, is the dominant source of error for quantifying individual plumes in homogeneous scenes. For heterogeneous scenes, the surface structure underlying the methane plume affects the plume masking and can become a dominant source of uncertainty.</p

Satellites Detect Abatable Super-Emissions in One of the World¿s Largest Methane Hotspot Regions

[EN] Reduction of fossil fuel-related methane emissions has been identified as an essential means for climate change mitigation, but emission source identification remains elusive for most oil and gas production basins in the world. We combine three complementary satellite data sets to survey single methane emission sources on the west coast of Turkmenistan, one of the largest methane hotspots in the world. We found 29 different emitters, with emission rates >1800 kg/h, active in the 2017¿2020 time period, although older satellite data show that this type of emission has been occurring for decades. We find that all sources are linked to extraction fields mainly dedicated to crude oil production, where 24 of them are inactive flares venting gas. The analysis of time series suggests a causal relationship between the decrease in flaring and the increase in venting. At the regional level, 2020 shows a substantial increase in the number of methane plume detections concerning previous years. Our results suggest that these large venting point sources represent a key mitigation opportunity as they emanate from human-controlled facilities, and that new satellite methods promise a revolution in the detection and monitoring of methane point emissions worldwide.The authors thank the team that realized the TROPOMI instrument and its data products, consisting of the partnership between Airbus Defense and Space Netherlands, KNMI, SRON, and TNO, commissioned by NSO and ESA. Sentinel-5 Precursor is part of the EU Copernicus program, Copernicus (modified) Sentinel-5P data (2018-2020) have been used. We thank the Sentinel Hub service for providing the EO Browser service. Thanks to the Environmental Defense Fund (EDF) for providing data about the O&G fields of the study area, and the Carbon Limits group for contributing to the verification of the emission sources. We thank the Italian Space Agency for the PRISMA data used in this work. Dr. Yongguang Zhang from the University of Nanjing is also thanked for his support to get access to ZY1 AHSI data, and Dr. Javier Gorrono from Universitat Politecnica de Valencia for his assistance in the uncertainty estimations. Authors Itziar Irakulis-Loitxate and Luis Guanter received funding from ESA Contract 4000134929.Irakulis-Loitxate, I.; Guanter-Palomar, LM.; Joannes D. Maasakkers; Daniel Zavala-Araiza; Ilse Aben (2022). Satellites Detect Abatable Super-Emissions in One of the World¿s Largest Methane Hotspot Regions. Environmental Science & Technology (Online). 56(4):2143-2152. https://doi.org/10.1021/acs.est.1c048732143215256

High-Resolution Methane Mapping with the EnMAP Satellite Imaging Spectroscopy Mission

Methane (CH4) mitigation from anthropogenic sources such as in the production and transport of fossil fuels has been found as one of the most promising strategies to curb global warming in the near future. Satellite-based imaging spectrometers have demonstrated to be well-suited to detect and quantify these emissions at high spatial resolution, which allows the attribution of plumes to sources. The PRecursore IperSpettrale della Missione Applicativa (PRISMA) satellite mission (ASI, Italy) has been successfully used for this application, and the recently launched Environmental Mapping and Analysis Program (EnMAP) mission (DLR/GFZ, Potsdam, Germany) presents similar spatial and spectral characteristics (30-m spatial resolution, 30-km swath, about 8-nm spectral sampling at 2300 nm). In this work, we investigate the potential and limitations of EnMAP for CH4 remote sensing, using PRISMA as a benchmark to deduce its added value. We analyze the spectral and radiometric performance of EnMAP in the 2300-nm region used for CH4 retrievals acquired using the matched-filter method. Our results show that in arid areas, EnMAP spectral resolution is about 2.7 nm finer and the signal-to-noise ratio values are approximately twice as large, which leads to an improvement in retrieval performance. Several EnMAP examples of plumes from different sources around the world with flux rate values ranging from 1 to 20 t/h are illustrated. We show plumes from sectors such as onshore oil and gas (O&G) and coal mining, but also from more challenging sectors such as landfills and offshore O&G. We detect two plumes in a close-to-sunglint configuration dataset with unprecedented flux rates of about 1 t/h, which suggests that the detection limit in offshore areas can be considerably lower under favorable conditions

UNEPs International Methane Emissions Observatory (IMEO): Bringing together policy-relevant methane emissions data

The International Methane Emissions Observatory (IMEO) was launched in 2021 at the G20 summit by the United Nations Environment Program (UNEP). UNEP’s IMEO exists to provide open, reliable, public, policy-relevant data to facilitate actions to reduce methane emissions. UNEP, through IMEO, aims to fill gaps in knowledge and refine global understanding of the location and magnitude of methane emissions across different anthropogenic sectors

A Methodology for Comparing the Surface Urban Heat Island in Selected Urban Agglomerations Around the World from Sentinel-3 SLSTR Data

[EN] Retrieval of land surface temperature (LST) from satellite data allows to estimate the surface urban heat island (SUHI) as the difference between the LST obtained in the urban area and the LST of its surroundings. However, this definition depends on the selection of the urban and surroundings references, which translates into greater difficulty in comparing SUHI values in different urban agglomerations across the world. In order to avoid this problem, a methodology is proposed that allows reliable quantification of the SUHI. The urban reference is obtained from the European Space Agency Climate Change Initiative Land Cover and three surroundings references are considered; that is, the urban adjacent (Su), the future adjacent (Sf), and the peri-urban (Sp), which are obtained from mathematical expressions that depend exclusively on the urban area. In addition, two formulations of SUHI are considered: SUHIMAX and SUHIMEAN, which evaluate the maximum and average SUHI of the urban area for each of the three surrounding references. As the urban population growth phenomenon is a world-scale problem, this methodology has been applied to 71 urban agglomerations around the world using LST data obtained from the sea and land surface temperature radiometer (SLSTR) on board Sentinel-3A. The results show average values of SUHIMEAN of (1.8 ± 0.9) °C, (2.6 ± 1.3) °C, and (3.1 ± 1.7) °C for Su, Sf, and Sp, respectively, and an average difference between SUHIMAX and SUHIMEAN of (3.1 ± 1.1) °C. To complete the study, two additional indices have been considered: the Urban Thermal Field Variation Index (UFTVI) and the Discomfort Index (DI), which proved to be essential for understanding the SUHI phenomenon and its consequences on the quality of life of the inhabitants.This research was funded by Ministerio de Ciencia, Innovacion y Universidades project ESP2017-85770-R.Sobrino, JA.; Irakulis-Loitxate, I. (2020). A Methodology for Comparing the Surface Urban Heat Island in Selected Urban Agglomerations Around the World from Sentinel-3 SLSTR Data. Remote Sensing. 12(12):1-29. https://doi.org/10.3390/rs12122052129121

Satellites Detect a Methane Ultra-emission Event from an Offshore Platform in the Gulf of Mexico

[EN] Mitigation of methane emissions from fossil fuel extraction, processing, and transport is one of the most effective ways to slow global warming. Satellite-based methods are instrumental for the detection, characterization, and quantification of this type of emissions. However, despite the rapid development of satellite-based methane plume detection methods for terrestrial surfaces, there is still an important observational gap with respect to offshore oil and gas infrastructure, which accounts for roughly 30% of global production. In this work, we have used observations from the WorldView-3 and Landsat 8 satellite missions in a particular observation-illumination geometry to image offshore methane plumes from space. The study site is an offshore oil and gas production platform in the Gulf of Mexico, near the coast of Campeche, in one of Mexico¿s major oil producing fields. Our data suggest that the platform vented high volumes of methane during a 17-day ultra-emission event, amounting to 0.04 ± 0.01 Tg of methane (equivalent to 3.36 million tons of carbon dioxide) released to the atmosphere if integrated over time. Our results illustrate how satellites can detect methane plumes from offshore infrastructure, which represents a significant breakthrough in the monitoring of industrial methane emissions from space.The authors thank the European Space Agency and European Space Imaging for access to WV3 data through the third-party mission plan. Javier Gorrono is funded by an ESA Living Planet Fellowship (ESA Contract No. 4000130980/20/I-NS). Authors Itziar Irakulis-Loitxate, Javier Gorron~o, and Luis Guanter received funding from ESA contract 4000134929. Elena Sanchez-Garcia is thanked for her support for the selection of the study site, and Maxar Technologies, Inc., for the acquisition of WV3 SWIR data for this study.Irakulis-Loitxate, I.; Gorroño-Viñegla, J.; Zavala-Araiza, D.; Guanter-Palomar, LM. (2022). Satellites Detect a Methane Ultra-emission Event from an Offshore Platform in the Gulf of Mexico. Environmental Science & Technology Letters. 9(6):520-525. https://doi.org/10.1021/acs.estlett.2c002255205259

Geostationary satellite observations of extreme and transient methane emissions from oil and gas infrastructure

We demonstrate geostationary satellite monitoring of large transient methane point sources with the US Geostationary Operational Environmental Satellites (GOES). GOES provides continuous 5- to 10-min coverage of the Americas at 1 to 2 km nadir pixel resolution in two shortwave infrared spectral bands from which large methane plumes can be retrieved. We track the full evolution of an extreme methane release from the El Encino-La Laguna natural gas pipeline in Durango, Mexico on 12 May 2019. The release lasted 3 h at a variable rate of 260 to 550 metric tons of methane per hour and totaled 1,130 to 1,380 metric tons. We report several other detections of transient point sources from oil/gas infrastructure, from which we infer a detection limit of 10 to 100 t h-1. Our results show that extreme releases of methane can last less than an hour, as from deliberate venting, and would thus be difficult to identify and quantify with low-Earth orbit satellites.ISSN:0027-8424ISSN:1091-649

Mapping methane plumes at very high spatial resolution with the WorldView-3 satellite

[EN] The detection of methane emissions from industrial activities can help enable effective climate change mitigation strategies. These industrial emissions, such as from oil and gas (O&G) extraction and coal mining, typically occur as large plumes of highly concentrated gas. Different satellite missions have recently shown the potential to map such methane plumes from space. In this work, we report on the promising potential of the WorldView-3 (WV-3) satellite mission for methane mapping. This relies on its unique very high spatial resolution (up to 3.7¿m) data in the shortwave infrared part of the spectrum, which is complemented by a good spectral sampling of the methane absorption feature at 2300¿nm and a high signal to noise ratio. The proposed retrieval methodology is based on the calculation of methane concentration enhancements from pixel-wise estimates of methane transmittance at WV-3 SWIR band 7 (2235¿2285¿nm), which is positioned at a highly-sensitive methane absorption region. A sensitivity analysis based on end-to-end simulations has helped to understand retrieval errors and detection limits. The results have shown the good performance of WV-3 for methane mapping, especially over bright and homogeneous areas. The potential of WV-3 for methane mapping has been further tested with real data, which has led to the detection of 26 independent point emissions over different methane hotspot regions, such as O&G extraction fields in Algeria and Turkmenistan, and the Shanxi coal mining region in China. In particular, the detection of very small leaks (<¿100¿kg¿h¿1) from oil pipelines in Turkmenistan shows the unique capability of WV-3 for mapping industrial methane emissions from space. The mission includes pointing capabilities that allow for a daily revisit over these oil pipelines or other critical infrastructure.This research has been supported by the ESA (contract no. 4000134929) and the ESA Living Planet Fellowship (ESA contract no. 4000130980/20/I-NS).Sánchez-García, E.; Gorroño-Viñegla, J.; Irakulis-Loitxate, I.; Varon, DJ.; Guanter-Palomar, LM. (2022). Mapping methane plumes at very high spatial resolution with the WorldView-3 satellite. Atmospheric Measurement Techniques. 15(6):1657-1674. https://doi.org/10.5194/amt-15-1657-20221657167415

Mapping methane point emissions with the PRISMA spaceborne imaging spectrometer

The authors would like to thank the Italian Space Agency, and inparticular Ettore Lopinto (Mission Director) , for the PRISMA data used in this work. Markus Foote (University of Utah) is also thanked for making the MAG1C code available to the scientific community. Javier Gorrono is funded by the ESA Living Planet Fellowship. PRISMA data can be accessed through the Data Access tab of PRISMA's website.1Guanter-Palomar, LM.; Irakulis-Loitxate, I.; Gorroño-Viñegla, J.; Sánchez-García, E.; Cusworth, DH.; Varon, DJ.; Cogliati, S.... (2021). Mapping methane point emissions with the PRISMA spaceborne imaging spectrometer. Remote Sensing of Environment. 265:1-14. https://doi.org/10.1016/j.rse.2021.112671S11426

Attribution of individual methane and carbon dioxide emission sources using EMIT observations from space.

Carbon dioxide and methane emissions are the two primary anthropogenic climate-forcing agents and an important source of uncertainty in the global carbon budget. Uncertainties are further magnified when emissions occur at fine spatial scales (&lt;1 km), making attribution challenging. We present the first observations from NASAs Earth Surface Mineral Dust Source Investigation (EMIT) imaging spectrometer showing quantification and attribution of fine-scale methane (0.3 to 73 tonnes CH4 hour-1) and carbon dioxide sources (1571 to 3511 tonnes CO2 hour-1) spanning the oil and gas, waste, and energy sectors. For selected countries observed during the first 30 days of EMIT operations, methane emissions varied at a regional scale, with the largest total emissions observed for Turkmenistan (731 ± 148 tonnes CH4 hour-1). These results highlight the contributions of current and planned point source imagers in closing global carbon budgets