Constraining the Mechanistic Effects of Spatial Resolution on Global Air Quality Modeling

The investigators in this project will perform a series of chemical transport model simulations in order to study the errors that arise in model simulations due to coarse horizontal resolution. Many modern chemical transport models, which are used to study atmospheric chemistry in our atmosphere, are computationally expensive, and as such many research groups continue to rely on relatively coarse resolution simulations. However, recent advancements have enabled higher spatial resolution simulations, and the investigators in this project will study biases and differences in model simulations that arise from different spatial resolutions. The knowledge gained in this project will enhance our ability to simulate and study smaller-scale atmospheric chemistry phenomena, is likely to increase confidence in and usage of high-resolution models in the future, and would enable more atmospheric chemistry research relevant to communities at the local and regional scale. In this proposed work, the investigators will utilize a high-performance implementation of GEOS-Chem (GCHP) that has recently developed distributed-memory parallelization that enables just this type of scale-varying research. There are three primary research goals in this proposed work: (1) to quantify and interpret the mechanistic resolution-dependence of non-linear chemistry with a focus on nitrogen oxide, ozone, and nitric acid; (2) to quantify and interpret the mechanistic resolution-dependence of emission segregation with a focus on nitrate aerosols; and (3) to quantify and interpret the errors in simulated air quality trends due to inadequate or too-coarse spatial resolution. Success in this work is therefore likely to have a positive impact on the GEOS-Chem, atmospheric chemistry, and climate-chemistry communities, as well as policy makers that could use these simulation results to make decisions regarding air quality within their own communities. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.