Evaluation of version 3.0B of the BEHR OMI NO2 product

Version 3.0B of the Berkeley High Resolution (BEHR) Ozone Monitoring Instrument (OMI) NO2 product is designed to accurately retrieve daily variation in the high-spatial-resolution mapping of tropospheric column NO2 over continental North America between 25 and 50 degrees N. To assess the product, we compare against in situ aircraft profiles and Pandora vertical column densities (VCDs). We also compare the WRF-Chem simulation used to generate the a priori NO2 profiles against observations. We find that using daily NO2 profiles improves the VCDs retrieved in urban areas relative to low-resolution or monthly a priori NO2 profiles by amounts that are large compared to current uncertainties in NOx emissions and chemistry (of the order of 10% to 30 %). Based on this analysis, we offer suggestions to consider when designing retrieval algorithms and validation procedures for upcoming geostationary satellites.