title: Estimating surface NO2and SO2mixing ratios from fast-response total column observations and potential application to geostationary missions.
abstract: Total-column nitrogen dioxide (NO2) data collected by a ground-based sun-tracking spectrometer system (Pandora) and an photolytic-converter-based in-situ instrument collocated at NASA's Langley Research Center in Hampton, Virginia were analyzed to study the relationship between total-column and surface NO2measurements. The measurements span more than a year and cover all seasons. Surface mixing ratios are estimated via application of a planetary boundary-layer (PBL) height correction factor. This PBL correction factor effectively corrects for boundary-layer variability throughout the day, and accounts for up to ≈75 % of the variability between the NO2data sets. Previous studies have made monthly and seasonal comparisons of column/surface data, which has shown generally good agreement over these long average times. In the current analysis comparisons of column densities averaged over 90 s and 1 h are made. Applicability of this technique to sulfur dioxide (SO2) is briefly explored. The SO2correlation is improved by excluding conditions where surface levels are considered background. The analysis is extended to data from the July 2011 DISCOVER-AQ mission over the greater Baltimore, MD area to examine the method's performance in more-polluted urban conditions where NO2concentrations are typically much higher.
authors.affiliation: Science Systems and Applications, Inc., Hampton, VA 23681 USA ; NASA Langley Research Center, Hampton, VA 23681 USA.
authors.forename: T
authors.initials: T
authors.lastname: Knepp
authors.affiliation: NASA Langley Research Center, Hampton, VA 23681 USA.
authors.forename: M
authors.initials: M
authors.lastname: Pippin
authors.affiliation: NASA Langley Research Center, Hampton, VA 23681 USA.
authors.forename: J
authors.initials: J
authors.lastname: Crawford
authors.affiliation: NASA Langley Research Center, Hampton, VA 23681 USA.
authors.forename: G
authors.initials: G
authors.lastname: Chen
authors.affiliation: US EPA, Research Triangle Park, Durham, NC 27701 USA.
authors.forename: J
authors.initials: J
authors.lastname: Szykman
authors.affiliation: US EPA, Research Triangle Park, Durham, NC 27701 USA.
authors.forename: R
authors.initials: R
authors.lastname: Long
authors.affiliation: NASA Langley Research Center, Hampton, VA 23681 USA.
authors.forename: L
authors.initials: L
authors.lastname: Cowen
authors.affiliation: LuftBlick, Kreith, 6162 Austria ; NASA Goddard Space Flight Center, Greenbelt, MD 20771 USA.
authors.forename: A
authors.initials: A
authors.lastname: Cede
authors.affiliation: NASA Goddard Space Flight Center, Greenbelt, MD 20771 USA ; School of Engineering, Morgan State University, Baltimore, MD 21251 USA.
authors.forename: N
authors.initials: N
authors.lastname: Abuhassan
authors.affiliation: Joint Center for Earth Systems Technology, University of Baltimore County, Baltimore, MD 21250 USA.
authors.forename: J
authors.initials: J
authors.lastname: Herman
authors.affiliation: Joint Center for Earth Systems Technology, University of Baltimore County, Baltimore, MD 21250 USA.
authors.forename: R
authors.initials: R
authors.lastname: Delgado
authors.affiliation: Joint Center for Earth Systems Technology, University of Baltimore County, Baltimore, MD 21250 USA.
authors.forename: J
authors.initials: J
authors.lastname: Compton
authors.affiliation: Joint Center for Earth Systems Technology, University of Baltimore County, Baltimore, MD 21250 USA.
authors.forename: T
authors.initials: T
authors.lastname: Berkoff
authors.affiliation: Department of Earth and Atmospheric Sciences, Saint Louis University, St. Louis, MO 63103 USA.
authors.forename: J
authors.initials: J
authors.lastname: Fishman
authors.affiliation: Department of Meteorology, Pennsylvania State University, University Park, PA 16802 USA.
authors.forename: D
authors.initials: D
authors.lastname: Martins
authors.affiliation: Department of Meteorology, Pennsylvania State University, University Park, PA 16802 USA.
authors.forename: R
authors.initials: R
authors.lastname: Stauffer
authors.affiliation: Department of Meteorology, Pennsylvania State University, University Park, PA 16802 USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Thompson
authors.affiliation: National Center for Atmospheric Research, Boulder, CO 80305 USA.
authors.forename: A
authors.initials: A
authors.lastname: Weinheimer
authors.affiliation: National Center for Atmospheric Research, Boulder, CO 80305 USA.
authors.forename: D
authors.initials: D
authors.lastname: Knapp
authors.affiliation: National Center for Atmospheric Research, Boulder, CO 80305 USA.
authors.forename: D
authors.initials: D
authors.lastname: Montzka
authors.affiliation: National Center for Atmospheric Research, Boulder, CO 80305 USA.
authors.forename: D
authors.initials: D
authors.lastname: Lenschow
authors.affiliation: NASA Langley Research Center, Hampton, VA 23681 USA.
authors.forename: D
authors.initials: D
authors.lastname: Neil
keywords: Air quality; CAPABLE; DISCOVER-AQ; GEO-CAPE; Nitrogen dioxide; Remote sensing; Sulfur dioxide