Articles | Volume 22, issue 19
https://doi.org/10.5194/acp-22-13183-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/acp-22-13183-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
14 Oct 2022
Research article |
| 14 Oct 2022
| 14 Oct 2022
Four-dimensional variational assimilation for SO2 emission and its application around the COVID-19 lockdown in the spring 2020 over China
Yiwen Hu
Key Laboratory for Aerosol–Cloud–Precipitation of China Meteorological
Administration, Nanjing University of Information Science & Technology,
Nanjing 210044, China
College of Meteorology and Oceanography, National University of
Defense Technology, Changsha 410073, China
Zengliang Zang
CORRESPONDING AUTHOR
College of Meteorology and Oceanography, National University of
Defense Technology, Changsha 410073, China
Key Laboratory for Aerosol–Cloud–Precipitation of China Meteorological
Administration, Nanjing University of Information Science & Technology,
Nanjing 210044, China
Yi Li
College of Meteorology and Oceanography, National University of
Defense Technology, Changsha 410073, China
Yanfei Liang
No. 32145 Unit of PLA, Xinxiang 453000, China
Wei You
College of Meteorology and Oceanography, National University of
Defense Technology, Changsha 410073, China
Xiaobin Pan
College of Meteorology and Oceanography, National University of
Defense Technology, Changsha 410073, China
Zhijin Li
Department of Atmospheric and Oceanic Sciences, Fudan University,
Shanghai 200031, China
Joint Institute for Regional Earth System Science and Engineering, University of California, Los Angeles, California 91109, USA
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Cited
13 citations as recorded by crossref.
- Improved hourly estimate of aerosol optical thickness over Asian land by fusing geostationary satellites Fengyun-4B and Himawari-9 Y. Cheng et al. https://doi.org/10.1016/j.scitotenv.2024.171541
- The Impact of Firework Ban Relaxation on Variations in SO2 Emissions in China During the 2023 Chinese New Year X. He et al. https://doi.org/10.3390/rs16224191
- Satellite-Based Emission Inversion for Air Pollutants and Greenhouse Gases: A Review Z. Jiang et al. https://doi.org/10.1007/s13351-025-4914-7
- Sensitivity and uncertainties assessment in radiative forcing due to aerosol optical properties in diverse locations in China F. Lu et al. https://doi.org/10.1016/j.scitotenv.2022.160447
- Unbalanced emission reductions of different species and sectors in China during COVID-19 lockdown derived by multi-species surface observation assimilation L. Kong et al. https://doi.org/10.5194/acp-23-6217-2023
- Updating and evaluating the NH3 gas-phase chemical mechanism of MOZART-4 in the WRF-Chem model G. Li et al. https://doi.org/10.1016/j.envpol.2023.122070
- Exploring aerosol–cloud interactions in liquid-phase clouds over eastern China and its adjacent ocean using the WRF-Chem–SBM model J. Zhao et al. https://doi.org/10.5194/acp-24-9101-2024
- The optimization of SO2 emissions by the 4DVAR and EnKF methods and its application in WRF-Chem Y. Hu et al. https://doi.org/10.1016/j.scitotenv.2023.163796
- How meteorological conditions influence aerosol-cloud interactions under different pollution regimes J. Zhao et al. https://doi.org/10.5194/acp-25-17701-2025
- Near-real-time inversion of SO₂ emission via coupled three-dimensional variational assimilation and deep learning surrogate framework over China H. Ye et al. https://doi.org/10.1016/j.atmosres.2026.109151
- Thermal comfort and air pollution nexus: A spatiotemporal perspective on China’s urbanization trajectory, 2014–2022 H. Wei et al. https://doi.org/10.1016/j.gr.2026.06.008
- Spatiotemporal optimization of NOx and VOC emissions using a hybrid inversion framework and implications for ozone sensitivity-regime diagnosis J. Moon et al. https://doi.org/10.5194/acp-26-10379-2026
- Next Generation Air Quality Models: Dynamical Mesh, New Insights into Mechanism, Datasets and Applications J. Li et al. https://doi.org/10.1007/s40726-025-00355-9
13 citations as recorded by crossref.
- Improved hourly estimate of aerosol optical thickness over Asian land by fusing geostationary satellites Fengyun-4B and Himawari-9 Y. Cheng et al. https://doi.org/10.1016/j.scitotenv.2024.171541
- The Impact of Firework Ban Relaxation on Variations in SO2 Emissions in China During the 2023 Chinese New Year X. He et al. https://doi.org/10.3390/rs16224191
- Satellite-Based Emission Inversion for Air Pollutants and Greenhouse Gases: A Review Z. Jiang et al. https://doi.org/10.1007/s13351-025-4914-7
- Sensitivity and uncertainties assessment in radiative forcing due to aerosol optical properties in diverse locations in China F. Lu et al. https://doi.org/10.1016/j.scitotenv.2022.160447
- Unbalanced emission reductions of different species and sectors in China during COVID-19 lockdown derived by multi-species surface observation assimilation L. Kong et al. https://doi.org/10.5194/acp-23-6217-2023
- Updating and evaluating the NH3 gas-phase chemical mechanism of MOZART-4 in the WRF-Chem model G. Li et al. https://doi.org/10.1016/j.envpol.2023.122070
- Exploring aerosol–cloud interactions in liquid-phase clouds over eastern China and its adjacent ocean using the WRF-Chem–SBM model J. Zhao et al. https://doi.org/10.5194/acp-24-9101-2024
- The optimization of SO2 emissions by the 4DVAR and EnKF methods and its application in WRF-Chem Y. Hu et al. https://doi.org/10.1016/j.scitotenv.2023.163796
- How meteorological conditions influence aerosol-cloud interactions under different pollution regimes J. Zhao et al. https://doi.org/10.5194/acp-25-17701-2025
- Near-real-time inversion of SO₂ emission via coupled three-dimensional variational assimilation and deep learning surrogate framework over China H. Ye et al. https://doi.org/10.1016/j.atmosres.2026.109151
- Thermal comfort and air pollution nexus: A spatiotemporal perspective on China’s urbanization trajectory, 2014–2022 H. Wei et al. https://doi.org/10.1016/j.gr.2026.06.008
- Spatiotemporal optimization of NOx and VOC emissions using a hybrid inversion framework and implications for ozone sensitivity-regime diagnosis J. Moon et al. https://doi.org/10.5194/acp-26-10379-2026
- Next Generation Air Quality Models: Dynamical Mesh, New Insights into Mechanism, Datasets and Applications J. Li et al. https://doi.org/10.1007/s40726-025-00355-9
Saved (final revised paper)
Latest update: 06 Aug 2026
Short summary
This study developed a four-dimensional variational assimilation (4DVAR) system based on WRF–Chem to optimise SO2 emissions. The 4DVAR system was applied to obtain the SO2 emissions during the early period of the COVID-19 pandemic over China. The results showed that the 4DVAR system effectively optimised emissions to describe the actual changes in SO2 emissions related to the COVID lockdown, and it can thus be used to improve the accuracy of forecasts.
This study developed a four-dimensional variational assimilation (4DVAR) system based on...
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