TY - JOUR A1 - Hu, Y. A1 - Zang, Z. A1 - Ma, X. A1 - Li, Y. A1 - Liang, Y. A1 - You, W. A1 - Pan, X. A1 - Li, Z. T1 - Four-dimensional variational assimilation for SO2 emission and its application around the COVID-19 lockdown in the spring 2020 over China JO - Atmos. Chem. Phys. J1 - ACP VL - 22 IS - 19 SP - 13183 EP - 13200 Y1 - 2022/10/14 PB - Copernicus Publications SN - 1680-7324 UR - https://acp.copernicus.org/articles/22/13183/2022/ L1 - https://acp.copernicus.org/articles/22/13183/2022/acp-22-13183-2022.pdf DO - 10.5194/acp-22-13183-2022 ER -