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Estimating Surface NO2 and SO2 Mixing Ratios from Fast-Response Total Column Observations and Potential Application to Geostationary Missions
Citation:
Knepp, T., M. Pippin, J. Crawford, Jim Szykman, R. Long, L. Cowen, A. Cede, N. Abuhassan, J. Herman, R. Delgado, J. Compton, T. Berkoff, J. Fishman, D. Martins, R. Stauffer, A. Thompson, A. Weinheimer, D. Knapp, D. Montzka, D. Lenschow, AND D. Neil. Estimating Surface NO2 and SO2 Mixing Ratios from Fast-Response Total Column Observations and Potential Application to Geostationary Missions. JOURNAL OF ATMOSPHERIC CHEMISTRY. Springer, New York, NY, 0(0):1-26, (2014).
Impact/Purpose:
Use of satellite and aircraft remote sensing observations to diagnose aerosol and trace gas gradients and concentrations associated with National Ambient Air Quality Standards (PM, NO2, O3, etc.)
Description:
Total-column nitrogen dioxide (NO2) data collected by a ground-based sun-tracking spectrometer system 21 (Pandora) and an photolytic-converter-based in-situ instrument collocated at NASA’s Langley Research Center in 22 Hampton, Virginia were analyzed to study the relationship between total-column and surface NO2 measurements. 23 The measurements span more than a year and cover all seasons. Surface mixing ratios are estimated via application 24 of a planetary boundary-layer (PBL) height correction factor. This PBL correction factor effectively corrects for 25 boundary-layer variability throughout the day, and accounts for up to ≈75% of the variability between the NO2 data 26 sets. Previous studies have made monthly and seasonal comparisons of column/surface data, which has shown 27 generally good agreement over these long average times. In the current analysis comparisons of column densities 28 averaged over 90 seconds and one hour are made. Applicability of this technique to sulfur dioxide (SO2) is briefly 29 explored. The SO2 correlation is improved by excluding conditions where surface levels are considered background. 30 The analysis is extended to data from the July 2011 DISCOVER-AQ mission over the greater Baltimore, MD area to 31 examine the method’s performance in more-polluted urban conditions where NO2 concentrations are typically much 32 higher.