The first evaluation of formaldehyde column observations by improved Pandora spectrometers during the KORUS-AQ field study

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dc.contributor.authorSpinei, Elena
dc.contributor.authorWhitehill, Andrew
dc.contributor.authorFried, Alan
dc.contributor.authorTiefengraber, Martin
dc.contributor.authorHerman, Jay
dc.contributor.authorAbuhassan, Nader
dc.contributor.authoret al
dc.date.accessioned2023-01-19T17:47:47Z
dc.date.available2023-01-19T17:47:47Z
dc.date.issued2018-08-31
dc.descriptionAuthors:- Elena Spinei, Andrew Whitehill, Alan Fried, Martin Tiefengraber, Travis N. Knepp, Scott Herndon, Jay R. Herman, Moritz Müller, Nader Abuhassan, Alexander Cede, Dirk Richter, James Walega, James Crawford, James Szykman, Lukas Valin, David J. Williams, Russell Long, Robert J. Swap, Youngjae Lee, Nabil Nowak, and Brett Pocheen_US
dc.description.abstractThe Korea–United States Air Quality Study (KORUS-AQ) conducted during May–June 2016 offered the first opportunity to evaluate direct-sun observations of formaldehyde (HCHO) total column densities with improved Pandora spectrometer instruments. The measurements highlighted in this work were conducted both in the Seoul megacity area at the Olympic Park site (37.5232◦ N, 27.1260◦ E; 26 m a.s.l.) and at a nearby rural site downwind of the city at the Mount Taehwa research forest site (37.3123◦ N, 127.3106◦ E; 160 m a.s.l.). Evaluation of these measurements was made possible by concurrent ground-based in situ observations of HCHO at both sites as well as overflight by the NASA DC-8 research aircraft. The flights provided in situ measurements of HCHO to characterize its vertical distribution in the lower troposphere (0–5 km). Diurnal variation in HCHO total column densities followed the same pattern at both sites, with the minimum daily values typically observed between 6:00 and 7:00 local time, gradually increasing to a maximum between 13:00 and 17:00 before decreasing into the evening. Pandora vertical column densities were compared with those derived from the DC-8 HCHO in situ measured profiles augmented with in situ surface concentrations below the lowest altitude of the DC-8 in proximity to the ground sites. A comparison between 49 column densities measured by Pandora vs. aircraft-integrated in situ data showed that Pandora values were larger by 16 % with a constant offset of 0.22 DU (Dobson units; R 2 = 0.68). Pandora HCHO columns were also compared with columns calculated from the surface in situ measurements over Olympic Park by assuming a wellmixed lower atmosphere up to a ceilometer-measured mixedlayer height (MLH) and various assumptions about the small residual HCHO amounts in the free troposphere up to the tropopause. The best comparison (slope = 1.03±0.03; intercept = 0.29±0.02 DU; and R 2 = 0.78±0.02) was achieved assuming equal mixing within ceilometer-measured MLH combined with an exponential profile shape. These results suggest that diurnal changes in HCHO surface concentrations can be reasonably estimated from the Pandora total column and information on the mixed-layer height. More work is needed to understand the bias in the intercept and the slope relative to columns derived from the in situ aircraft and surface measurements.en_US
dc.description.sponsorshipThe authors would like to acknowledge the National Institute of Environmental Research (NIER) for its tremendous effort during KOUR-AQ. In particular we would like to thank NIER for its effort in establishing the Olympic Park research site and their assistance with logistics for measurements at both Olympic Park and Mt. Taewha Forest. This work was supported under the NASA Tropospheric Chemistry Program and the EPA Air, Climate, and Energy Research Program. Although this paper has been reviewed by the EPA and approved for publication, it does not necessarily reflect EPA policies or views. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.en_US
dc.description.urihttps://amt.copernicus.org/articles/11/4943/2018/en_US
dc.format.extent19 pagesen_US
dc.genrejournal articlesen_US
dc.identifierdoi:10.13016/m2popm-5kb6
dc.identifier.citationSpinei, E., et al. “The first evaluation of formaldehyde column observations by improved Pandora spectrometers during the KORUS-AQ field study” Atmos. Meas. Tech. 11 (31 Aug 2018): 4943–4961. https://doi.org/10.5194/amt-11-4943-2018.en_US
dc.identifier.urihttps://doi.org/10.5194/amt-11-4943-2018
dc.identifier.urihttp://hdl.handle.net/11603/26671
dc.language.isoen_USen_US
dc.publisherEGUen_US
dc.relation.isAvailableAtThe University of Maryland, Baltimore County (UMBC)
dc.relation.ispartofUMBC Joint Center for Earth Systems Technology
dc.relation.ispartofUMBC Faculty Collection
dc.rightsThis work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.en_US
dc.rightsPublic Domain Mark 1.0*
dc.rights.urihttp://creativecommons.org/publicdomain/mark/1.0/*
dc.titleThe first evaluation of formaldehyde column observations by improved Pandora spectrometers during the KORUS-AQ field studyen_US
dc.typeTexten_US
dcterms.creatorhttps://orcid.org/0000-0002-9146-1632en_US
dcterms.creatorhttps://orcid.org/0000-0002-3865-657Xen_US

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