Comparative study of GEOS-Chem and WRF-GC in the United States

GEOS-Chem is a widely used three-dimensional atmospheric chemical transport model that is driven by the GEOS reanalysis data over global to regional scales. WRF-GC is a new, online coupled model based on the regional meteorology model, WRF, and the chemical mechanisms of GEOS-Chem. This study used these two models to simulate ozone, sulfur oxides, and nitrogen oxides in the United States, and compare the results between the two models and with observations. Surface concentration observations over the same period were derived from daily observations collected over more than 2000 surface sites from the US Environmental Protection Agency Air Quality System (EPA-AQS) and the Clean Air Status and Trends Network (CASNET). Through comparative analysis, we will evaluate in detail the differences of the two models in different pollutant simulations and attribute these differences to differences in the driving meteorological fields.