Systematic Analysis of DISCOVER-AQ Nitrogen Dioxide Observations for Improved Column-to-Surface Relationship Diagnosis

Can surface air quality be estimated from satellite column observations of trace gases? What factors influence the relationship between column and surface observations? How do boundary layer dynamics and chemistry interact to determine the spatial and vertical distribution and evolution of nitrogen dioxide (NO₂)? How do these factors affect NO₂ retrievals from orbital and sub-orbital observations? To address these questions, we conduct a systematic analysis of concurrent, integrated observations of column abundances from orbital (Ozone Monitoring Instrument (OMI)) and suborbital sensors, vertical profiling from aircraft, and in situ surface concentrations during the DISCOVER-AQ campaigns. We explore the impact of atmospheric chemistry and meteorological parameters for influencing the relationship between column and surface-level NO₂. We use high-resolution meteorological (Weather Research and Forecasting (WRF)) and air quality modeling (Community Multi-scale Air Quality (CMAQ)) simulations of each DISCOVER-AQ campaign to interpret these observations, provide a priori information for NO₂ retrievals, and diagnose both chemistry and meteorology affecting column-to-surface relationship, as well as potential model deficiencies.