Evaluation of OMI NO2 Vertical Columns Using MAX-DOAS Observations over Mexico City

Nitrogen dioxide (NO2) is a gas pollutant that can be measured from space and several operational products are now available instruments on-board of satellite-based platforms. There still, however, many unknowns about the accuracy these under different viewing surface conditions since ground-based observations generally scarce. This particularly case high-altitude sub-tropical megacities such as Mexico City Metropolitan Area (MCMA). In this study, we use more than five years data four MAX-DOAS distributed within MCMA in order to evaluate DOMINO product Ozone Monitoring Instrument (OMI) on board Aura satellite. We compare OMI against each site independently using vertical column densities (VCDs) reported by instrument. The VCDs also compared after smoothing profiles with priori Averaging Kernels satellite product. obtain an overall correlation coefficient (R) 0.6 does not improve significantly applied. However, slopes linear regressions for individual sites when applying 0.36 0.62 at UNAM, 0.26 0.49 Acatlán, 0.78 1.23 Vallejo, 0.50 0.97 Cuautitlán station. large differences observed between attributed reduced sensitivity near aerosol loading typically present mixed layer MCMA. may contribute slight overestimation measurements presents total error (random + systematic) 20%. As result comparison, find retrievals average 56% lower without any correction. near-surface concentrations estimated lowest layers well situ analyzers operated co-located air quality monitoring stations. diurnal variability station analyzed discussed relation their location city.