Key Laboratory for Ecological Environment in Coastal Areas, National Marine Environmental Monitoring Center, Ministry of Ecology and Environment, Dalian, China.
State Key Laboratory of Severe Weather & Key Laboratory of Atmospheric Chemistry of China Meteorological Administration (CMA), Chinese Academy of Meteorological Sciences, Beijing, China.
Environ Pollut. 2020 Aug;263(Pt B):114486. doi: 10.1016/j.envpol.2020.114486. Epub 2020 Apr 2.
Although oil and gas explorations contribute to atmospheric methane (CH) emissions, their impact and influence along the shelf seas of China remain poorly understood. From 2012 to 2017, we conducted four ship-based surveys of CH in the seawater column and boundary layer of the Bohai Sea, China, and further measured CO and several meteorological parameters. The average observed CH mixing ratios in the boundary layer and its concentrations in seawater column were 1950 ± 46 ppb in November 2012 (dissolved CH was not observed in this survey), 2222 ± 109 ppb and 13.0 ± 5.9 nmol/L in August 2014, 2014 ± 20 ppb and 5.4 ± 1.4 nmol/L in February 2017, and 1958 ± 25 ppb and 5.3 ± 3.8 nmol/L in May 2017, respectively. The results demonstrated that the CH emissions from the oil and gas platforms accounted for approximately 72.5 ± 27.0% of the increase in the background atmospheric CH in the local area. The remaining emissions were attributed to land-sea air mass transportation. Conversely, the influence of the air-sea exchange was negligible, measuring within the 10 ppb range. For carbon balance calibration, the mean flaring efficiency of the oil-associated gas based on the enhancement of CO (ΔCO) and enhancement sum of CO and CH (ΔCO + ΔCH) was 98.5 ± 0.5%. Furthermore, the CH emission rate from the oil and gas platforms was 0.026 ± 0.017 Tg/year, which was approximately 7.2 times greater than the sea-to-air CH flux over the entire Bohai Sea area. Thus, oil and gas platforms must be recognized as important artificial hotspot sources of atmospheric CH in the Bohai Sea.
尽管石油和天然气勘探会导致大气甲烷（CH）排放，但它们在中国近海的影响和作用仍未得到充分了解。2012 年至 2017 年，我们在中国渤海进行了四次基于船舶的海水柱和边界层 CH 调查，并进一步测量了 CO 和一些气象参数。2012 年 11 月（本次调查未观测到溶解态 CH），边界层中观测到的平均 CH 混合比和海水柱中的浓度分别为 1950 ± 46 ppb 和 13.0 ± 5.9 nmol/L；2014 年 8 月，2222 ± 109 ppb 和 13.0 ± 5.9 nmol/L；2017 年 2 月，2014 ± 20 ppb 和 5.4 ± 1.4 nmol/L；2017 年 5 月，1958 ± 25 ppb 和 5.3 ± 3.8 nmol/L。结果表明，油气平台的 CH 排放量约占当地背景大气 CH 增加量的 72.5 ± 27.0%。其余的排放归因于陆海气团输送。相反，海气交换的影响可以忽略不计，在 10 ppb 范围内。为了碳平衡校准，基于 CO（ΔCO）增强和 CO 和 CH 增强总和（ΔCO + ΔCH）的油相关气体的平均火炬效率为 98.5 ± 0.5%。此外，油气平台的 CH 排放量为 0.026 ± 0.017Tg/年，约为整个渤海海域海气 CH 通量的 7.2 倍。因此，油气平台必须被视为渤海大气 CH 的重要人工热点源。
