Articles | Volume 22, issue 19
Research article
14 Oct 2022
Research article |  | 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, Zengliang Zang, Xiaoyan Ma, Yi Li, Yanfei Liang, Wei You, Xiaobin Pan, and Zhijin Li

Data sets

NCEP FNL Operational Model Global Tropospheric Analyses National Centers for Environmental Prediction/National Weather Service/NOAA/US Department of Commerce

MEICv1.0-v1.3 Tsinghua University

Real-time national air quality China National Environmental Monitoring Centre

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.
Final-revised paper