Tropospheric and total NO2 column comparison between ground-based MFDOAS and Aura/OMI retrievals in rural and polluted airsheds.

NO2 total and tropospheric columns were measured by the Washington State University Multi-Function DOAS instrument in clean and polluted conditions at the NASA JPL Table Mountain Facility, CA, rural Pullman, WA and the NASA Goddard Space Flight Center, MD during summer and fall 2007. Vertical NO2 columns were derived from both direct sun and scattered sky observations using air mass factors (AMF) calculated geometrically for direct sun observations and the LIDORT v3.3 radiative transfer model for the sky-scattered radiances. The AIRPACT-3 Pacific Northwest regional air quality forecast system was used to predict a priori NO2 profiles for LIDORT interpretation of the Pullman data. NO2 total and tropospheric columns are compared to Aura/OMI NO2 retrievals as well as in-situ measurements.