A Hierarchical Modeling Approach to Understanding Tropospheric Ozone

Abstract

Tropospheric ozone is crucial for the oxidative capacity of the atmosphere and for surface air pollution. Today, a number of uncertainties exist regarding the behavior of ozone, which greatly reduces our ability to make predictions on the impact of climate change on tropospheric ozone. Current state of the art chemistry models do not consistently model chemical transport, and changes to transport due to climate change are likewise inconsistent between models. I propose a new approach to evaluating ozone trends: employing idealized general circulation models to drive chemical transport models. I use the Isca idealized modeling framework to produce meteorological fields which are imported into GEOS-Chem, a comprehensive chemical transport model. By altering the parameters of the idealized model, I am able to force changes in the meteorological fields and evaluate their impact on the chemistry produced within GEOS-Chem. My results exhibit statistically significant differences in ozone concentrations as well as ozone chemistry between the simulations. They highlight the importance of stratospheric injection and chemical transport on ozone behavior. Additionally, the results demonstrate that evaluation of the impact of atmospheric dynamics on ozone behavior within chemical transport models is possible through a hierarchical modeling approach. This approach has the potential to improve understanding of the factors critical to the tropospheric ozone budget. This work provides a proof of concept for a new framework to understand the interactions of atmospheric chemistry and atmospheric physics.