# Measuring Gas Flaring in Russia with Multispectral VIIRS Nightfire
## 4 Discussion
### Seasonality in Observation and Effect of COVID-19 Pandemic on Gas Flaring  
In Russia, approximately 65% of all detected gas flares are located north of 60\({}^{\circ}\)N latitude, while approximately 23% of them are situated to the north of the Arctic Circle (66.562\({}^{\circ}\)N), with major oil fields being commissioned in the higher latitudes in recent years. This fact makes the flaring situation in Russia unique, as other regions in the world with gas flaring occurring above the 60\({}^{\circ}\) latitude--such as the Norwegian Sea, northern parts of the Northern Sea and Alaska--are estimated to flare significantly lower volumes of gas and, excluding Alaska, are located to the south of the Arctic Circle. Our normalization approach to correct the annual mean \(RH\)' for cloud-free observations is robust against the summer detection dropouts in northern Russia. However, the monthly flared gas volumes in Russia for the months May-July will be underestimated if they are based on night-time observations. For example, flares that remained detectable in June 2019 comprised 45% of the total flare count in Russia, with the northernmost detectable flares situated at 60.8\({}^{\circ}\)N. These flares accounted for 38% of the estimated flared BCM in January or December in 2019, i.e., the raw June BCM estimate of approximately 0.73 BCM should be recalculated to approximately 2.5 BCM based on December gas flare activity. In the seasonality analysis below, we interpolate the May-July volumes from other months using non-smoothing Akima splines [59]. Later in this section, we also discuss another possibility to fill the summer months with daytime observations using the Active Fire Product. We decompose the monthly flaring time series into three components: trend, seasonal and residual. To extract smooth estimates of the three components, we utilize locally estimated scatterplot smoothing algorithm (LOESS) [60]. In Figure 12, we compare seasonal-trend decompositions for the national-level upstream monthly flared gas volumes for Russia and the US in 2012-2020. In Russia, we observe higher seasonal variations relative to the long-term trend. In both countries, the peak of the flaring season is observed in summer, and the lowest flaring is observed in winter. A possible interpretation of this phenomenon is that in winter, a large volume of gas is used for heating and increased power generation. Figure 11: (a) VIIRS Nightfire gas flares’ mean temperature (in K) relative frequency distribution in Russia for gas flares located at oil and natural gas/gas condensate upstream facilities. Relative frequencies are calculated independently. (b) Gas flaring volume (in BCM) distribution by mean temperature (in K). Figure 12: Comparison of VIIRS Nightfire-estimated monthly fluctuations in gas flaring in Russia (**a**) and the USA (**b**). The charts present, from top to bottom, monthly variations in flaring volume (in BCM) and its decomposition into the seasonal component, trend, and residuals. Summer data for Russia are interpolated (dashed line). (**c**,**d**) show the highest and lowest monthly flaring rates observed in Russia and USA, respectively (dots correspond to annual data, with line being the average date). The COVID-19 pandemic has strong implications on the world oil and gas market. In Figure 13, we compare the monthly flared gas volumes in Russia and the US in 2020. We observe a significant drop in the US flaring starting from March, which is opposite to the seasonal variations in previous years. By contrast, in Russia, the 2020-2021 flaring season is not different from the past observations, with the peak of the long-term trend happening in summer 2020. Several oil fields in Russia have shown a decline in flaring (namely Priobskoye, the largest oil producing field in Russia in recent years [45]), while Odoptu field in Sakhalin was forced to completely shut down its production in July 2020 [61]. For the latter, the last flaring event was observed in November, with a major decrease in monthly flaring volumes in June 2020.