Relationship between column-density and surface mixing ratio: Statistical analysis of O₃ and NO₂ data from the July 2011 Maryland DISCOVER-AQ mission

Abstract

To investigate the ability of column (or partial column) information to represent surface air quality, results of linear regression analyses between surface mixing ratio data and column abundances for O₃ and NO₂ are presented for the July 2011 Maryland deployment of the DISCOVER-AQ mission. Data collected by the P-3B aircraft, ground-based Pandora spectrometers, Aura/OMI satellite instrument, and simulations for July 2011 from the CMAQ air quality model during this deployment provide a large and varied data set, allowing this problem to be approached from multiple perspectives. O₃ columns typically exhibited a statistically significant and high degree of correlation with surface data (R² > 0.64) in the P-3B data set, a moderate degree of correlation (0.16 < R² < 0.64) in the CMAQ data set, and a low degree of correlation (R² < 0.16) in the Pandora and OMI data sets. NO₂ columns typically exhibited a low to moderate degree of correlation with surface data in each data set. The results of linear regression analyses for O₃ exhibited smaller errors relative to the observations than NO₂ regressions. These results suggest that O₃ partial column observations from future satellite instruments with sufficient sensitivity to the lower troposphere can be meaningful for surface air quality analysis.