Did an Increased Tropospheric Ozone Concentration Cause Atmospheric Circulation Change in Recent Decades?

Tropospheric ozone (TO3) concentration has kept increasing over the East Asia during last few decades. The related radiation change in the troposphere has been suggested to modify not only the local atmospheric circulation but also the global atmospheric circulation extending even to the Southern Hemisphere. However, due to the limited observations, these results are mostly based on the selected climate model experiments with a significant uncertainty. To better understand TO3-related circulation changes, the present study revisits this issue with two different atmospheric general circulation models that are independent with each other. Using these models, i.e., the Global and Regional Integrated Modeling System version 2 (GRIMs2) and the Community Atmospheric Model version 5 (CAM5), time slice experiments are performed for 1960s and 2000s TO3 conditions with identical surface boundary conditions and other greenhouse gas concentrations. The comparison of background flow and various climate indices (i.e., Arctic Oscillation, Asian monsoon indices, etc.) between the two experiments, however, shows no significant differences in both GRIMs2 and CAM5. These results suggest that TO3 change alone may not be able to cause atmospheric circulation changes even in regional scale.