Tohjima Yasunori, Niwa Yosuke, Patra Prabir K, Mukai Hitoshi, Machida Toshinobu, Sasakawa Motoki, Tsuboi Kazuhiro, Saito Kazuyuki, Ito Akihiko
National Institute for Environmental Studies (NIES), 16-2 Onogawa, Tsukuba, Ibaraki 305-8506 Japan.
Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 3173-25 Showa-Machi, Kanazawa-Ku, Yokohama, Kanagawa 236-0001 Japan.
Prog Earth Planet Sci. 2023;10(1):10. doi: 10.1186/s40645-023-00542-6. Epub 2023 Mar 2.
We developed a near-real-time estimation method for temporal changes in fossil fuel CO (FFCO) emissions from China for 3 months [January, February, March (JFM)] based on atmospheric CO and CH observations on Hateruma Island (HAT, 24.06° N, 123.81° E) and Yonaguni Island (YON, 24.47° N, 123.01° E), Japan. These two remote islands are in the downwind region of continental East Asia during winter because of the East Asian monsoon. Previous studies have revealed that monthly averages of synoptic-scale variability ratios of atmospheric CO and CH (ΔCO/ΔCH) observed at HAT and YON in JFM are sensitive to changes in continental emissions. From the analysis based on an atmospheric transport model with all components of CO and CH fluxes, we found that the ΔCO/ΔCH ratio was linearly related to the FFCO/CH emission ratio in China because calculating the variability ratio canceled out the transport influences. Using the simulated linear relationship, we converted the observed ΔCO/ΔCH ratios into FFCO/CH emission ratios in China. The change rates of the emission ratios for 2020-2022 were calculated relative to those for the preceding 9-year period (2011-2019), during which relatively stable ΔCO/ΔCH ratios were observed. These changes in the emission ratios can be read as FFCO emission changes under the assumption of no interannual variations in CH emissions and biospheric CO fluxes for JFM. The resulting average changes in the FFCO emissions in January, February, and March 2020 were 17 ± 8%, - 36 ± 7%, and - 12 ± 8%, respectively, (- 10 ± 9% for JFM overall) relative to 2011-2019. These results were generally consistent with previous estimates. The emission changes for January, February, and March were 18 ± 8%, - 2 ± 10%, and 29 ± 12%, respectively, in 2021 (15 ± 10% for JFM overall) and 20 ± 9%, - 3 ± 10%, and - 10 ± 9%, respectively, in 2022 (2 ± 9% for JFM overall). These results suggest that the FFCO emissions from China rebounded to the normal level or set a new high record in early 2021 after a reduction during the COVID-19 lockdown. In addition, the estimated reduction in March 2022 might be attributed to the influence of a new wave of COVID-19 infections in Shanghai.
The online version contains supplementary material available at 10.1186/s40645-023-00542-6.
我们基于对日本波照间岛（HAT，北纬24.06°，东经123.81°）和与那国岛（YON，北纬24.47°，东经123.01°）的大气CO和CH观测，开发了一种近实时估算方法，用于估算中国化石燃料CO（FFCO）排放3个月[1月、2月、3月（JFM）]的时间变化。由于东亚季风，这两个偏远岛屿在冬季处于东亚大陆的下风区域。先前的研究表明，在JFM期间在HAT和YON观测到的大气CO和CH的天气尺度变率比（ΔCO/ΔCH）的月平均值对大陆排放变化敏感。通过基于包含CO和CH通量所有成分的大气传输模型的分析，我们发现ΔCO/ΔCH比与中国的FFCO/CH排放比呈线性相关，因为计算变率消除了传输影响。利用模拟的线性关系，我们将观测到的ΔCO/ΔCH比转换为中国的FFCO/CH排放比。计算了2020 - 2022年排放比相对于前9年（2011 - 2019年）的变化率，在此期间观测到相对稳定的ΔCO/ΔCH比。在假设JFM期间CH排放和生物圈CO通量无年际变化的情况下，这些排放比的变化可解读为FFCO排放变化。相对于2011 - 2019年，2020年1月、2月和3月FFCO排放的平均变化分别为17±8%、 - 36±7%和 - 12±8%（JFM总体为 - 10±9%）。这些结果与先前的估计总体一致（2021年1月、2月和3月的排放变化分别为18±8%、 - 2±10%和29±12%，JFM总体为15±10%；2022年分别为20±9%、 - 3±10%和 - 10±9%，JFM总体为2±9%）。这些结果表明，中国的FFCO排放在新冠疫情封锁期间减少后，于2021年初反弹至正常水平或创下新的高纪录。此外，2022年3月估计的减排可能归因于上海新一轮新冠感染的影响。
在线版本包含可在10.1186/s40645 - 023 - 00542 - 6获取的补充材料。
