Ozone Monitoring Instrument (OMI) Aura nitrogen dioxide standard product version 4.0 with improved surface and cloud treatments

Abstract. We present a new and improved version (V4.0) of the NASA standard nitrogen dioxide (NO2) product from Ozone Monitoring Instrument (OMI) on Aura satellite. This incorporates most salient improvements for OMI NO2 products suggested by expert users enhances data quality in several ways through to air mass factors (AMFs) used retrieval algorithm. The algorithm is based geometry-dependent surface Lambertian equivalent reflectivity (GLER) operational that available an pixel basis. GLER calculated using vector linearized discrete ordinate radiative transfer (VLIDORT) model, which uses as input high-resolution bidirectional reflectance distribution function (BRDF) information NASA's Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) instruments over land wind-dependent Cox–Munk wave-facet slope water, latter with contribution water-leaving radiance. combined consistently retrieved oxygen dimer (O2–O2) absorption-based effective cloud fraction (ECF) optical centroid pressure (OCP) provide AMF calculations. AMFs increase tropospheric up 50 % highly polluted areas; these differences arise both BRDF effects well biases between MODIS-based previously OMI-based climatological sets. quantitatively evaluate independent observations ground-based airborne instruments. V4.0 relevant explanatory documentation are publicly Goddard Earth Sciences Data Information Services Center (https://disc.gsfc.nasa.gov/datasets/OMNO2_V003/summary/, last access: 8 November 2020), we encourage their use previous versions products.