Analysis of Variability in Formaldehyde and Ozone Column Densities

Abstract:

Recent analysis of data collected during the DISCOVER-AQ field campaign has shown a strong correlation between lower-tropospheric integrated column densities of formaldehyde (HCHO) and ozone (O₃). In order for this knowledge to be applicable to the monitoring of near-surface pollution from satellites, further analysis must be undertaken to understand variability in this relationship as the length of the vertical column is changed (for example, is the correlation still evident if we use total tropospheric columns?). Proposed analysis will use in-situ measurements of HCHO and O₃ collected onboard the NASA P-3B and varying column depths to investigate this trend. This will necessitate an accurate approximation of the boundary layer height, as nearly all of the HCHO vertical column is contained therein. VOCs measured at surface sites during the California and Colorado employments will be used to analyze the contribution of different emissions sources over these study regions, which may provide valuable insight into variabilities into the HCHO/O₃ column relationship. Furthermore, surface measurements of HCHO were taken at one site in Colorado, and will be used to analyze variability in the surface-column relationship for HCHO. An accurate understanding of the variabilities in these trends (i.e. the relationship between HCHO and O₃ columns, the relationship between column densities and the contribution of different emission sources, and the surface-column relationship for HCHO) in the four DISCOVER-AQ study regions (Maryland, Houston, California, and Colorado) will provide insight into how effective HCHO could potentially be in understanding surface pollution during different seasons and under different atmospheric composition regimes.