The COVID-19 pandemic caused disruptions of public life and imposed lockdown measures in 2020 resulted in considerable reductions of anthropogenic aerosol emissions. It still remains unclear how the associated short-term changes in atmospheric chemistry influenced weather and climate on regional scales. To understand the underlying physical mechanisms, we conduct ensemble aerosol perturbation experiments with the Community Earth System Model, version 2. In the simulations reduced anthropogenic aerosol emissions in February generate anomalous surface warming and warm-moist air advection which promotes low-level cloud formation over China. Although the simulated response is weak, it is detectable in some areas, in qualitative agreement with the observations. The negative dynamical cloud feedback offsets the effect from reduced cloud condensation nuclei. Additional perturbation experiments with strongly amplified air pollution over China reveal a nonlinear sensitivity of regional atmospheric conditions to chemical/radiative perturbations. COVID-19-related changes in anthropogenic aerosol emissions provide an excellent testbed to elucidate the interaction between air pollution and climate.
【저자키워드】 Climate sciences, Atmospheric science, 【초록키워드】 observations, lockdown, COVID-19 pandemic, China, sensitivity, Model, Air pollution, mechanisms, Climate, experiment, weather, Interaction, life, in some, reduction, Emissions, atmospheric conditions, cloud condensation nuclei, measure, Version, perturbations, emission, earth, System, physical, nuclei, amplified, caused, detectable, generate, reduced, changes in, promote, anthropogenic, atmospheric, atmospheric condition, offset, 【제목키워드】 COVID-19, lockdown, China, measure, East Asian,