Figure 11.

Impact of dynamic PV scaling parameterization on model performance for surface-level seasonal mean maximum daily 8-hour average O₃ (MD8O₃) at CASTNET sites in the U.S. The model estimated stratospheric contribution is estimated as the difference between the simulation with the dynamic PV scaling and one without. The bias change is estimated as the difference between the absolute bias in the simulation with a constant-PV (20 PV) scaling and the absolute bias in the dynamic-PV scaling simulations. Positive changes in bias represent reduction in bias due to dynamic-PV, while negative changes represent an increase in bias in simulated surface MD8O₃. Seasonal means are computed based on model-observed pairs when the observed MD8O₃ >40 ppb.