Validation of OMI tropospheric NO₂ column data using MAX-DOAS measurements deep inside the North China Plain in June 2006: Mount Tai Experiment 2006

Abstract. A challenge for the quantitative analysis of tropospheric nitrogen dioxide (NO₂) column data from satellite observations is posed partly by the lack of satellite-independent observations for validation. We performed such observations of the tropospheric NO₂ column using the ground-based Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) technique in the North China Plain (NCP) from 29 May to 29 June, 2006. Comparisons between tropospheric NO₂ columns measured by MAX-DOAS and the Ozone Monitoring Instrument (OMI) onboard the Aura satellite indicate that OMI data (the standard product, version 3) over NCP may have a positive bias of 1.6×10¹⁵ molecules cm⁻² (20%), yet within the uncertainty of the OMI data. Combining these results with literature validation results for the US, Europe, and Pacific Ocean suggests that a bias of +20%/−30% is a reasonable estimate, accounting for different regions.