# Measuring Gas Flaring in Russia with Multispectral VIIRS Nightfire
## 5 Conclusions  
The result of this paper is a digital catalog of the Russian gas flares observed with Suomi NPP satellite in the period of 2012-2020. For each flare, we report its geographical and economical metadata, including location, temperature, detection frequency, annual flared volume (in million cubic meters, MCM), type of facility (e.g., oil field or gas processing plant), and ownership. We provide technical details on the updated method for flare detection and characterization, including watershed of the detection probability map to define flare contours, aggregation of the VNF time series within the flare contours by month or by year, normalization of these aggregates for the cloud-free observations, correction for flare geometry and satellite view angle, non-linear correction of the Stefan-Boltzmann law for flare radiative heat, and confidence levels in calibration for the survey of gas flaring using VNF data. During the observation period of 2012-2020, 3220 unique gas flare annual detections in Russia were validated in this study. Annually, approximately 1350 gas flares have been detected on average, with a decrease in 2020 to 1241 detections. These detections correspond to 1063 unique objects-separate entities, such as oil and gas fields, exploration drillings, and midstream or downstream objects. Upstream flaring has been detected in 27 federal subjects of Russia, with downstream flaring occurring in 12 more regions. On the company level, 293 separate subsidiaries have been attributed at least one active gas flare. In the global context, gas flaring volumes in Russia are estimated to average at 23 BCM annually (15% of global estimated flaring), with 19 BCM (c. 82% on national scale) corresponding to oil upstream facilities burning associated petroleum gas (APG), which has been subject to heavy government regulations since 2013. Although initially dropping, observed flaring volumes have been on the climb since 2018 and, despite the setbacks of 2020 and a subsequent reported drop in oil production in Russia by 9%, flaring volumes are estimated to have reached their peak (25.5 BCM) this year (21 BCM in oil upstream sector), although global flaring has dropped by 5%. VIIRS Nightfire estimates were in better agreement with the official data reported by the Ministry of Energy of the Russian Federation and Rosstat (Russian Federal State Statistics Service) in 2012-2013 and 2019, while in 2015-2016, its estimates exceeded reported data by c. 70%. On a regional scale, Khanty-Mansi Autonomous Okrug, Yugra (KhMAO), as the major oil producing region in Russia, is estimated to remain the largest APG flaring region in the country, although Nightfire estimates exceed the reported data by a factor of 2.5. Flaring in the region has also dropped significantly in 2012-2017 and remains at the 4.5 BCM mark. In 2019-2020, combined upstream flaring (including natural gas and gas condensate facilities) in Yamal-Nenets Autonomous Okrug is estimated to have surpassed flaring in KhMAO (5 BCM), although approximately 50% of the flaring volume was categorized as \"natural gas upstream\" in this study. Other major flaring regions are Irkutsk Oblast (3.5 BCM in 2020), Krasnoyarsk Krai (3 BCM), and Orenburg Oblast (2.3 BCM). On the company level, the largest oil producer, Rosenft, is also the largest flaring entity, comprising 38% of the national flaring levels (estimates include joint ventures). Approximately 14% and 12% of the flaring volume is related to Gazprom Neft and Lukoil facilities, respectively, although the latter reports significantly lower flaring volumes. The major oil producers Surgutneftegas and Tatneft flare less than 0.1 BCM of their APG annually, and are confirmed to have reached the 95% APG utilization goal. Although the correlation with company-reported flaring data (see Figure 8) is strong (R\({}^{2}\) = 0.9), annual estimates for the largest companies experience significant scatter, while other companies tend to be overestimated with Nightfire.