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Airborne DOAS limb measurements of tropospheric trace gas profiles: Case studies on the profile retrieval of O 4 and BrO

dc.contributor.authorPrados-Roman, C.
dc.contributor.authorButz, A.
dc.contributor.authorDeutschmann, T.
dc.contributor.authorDorf, M.
dc.contributor.authorKritten, L.
dc.contributor.authorMinikin, A.
dc.contributor.authorPlatt, U.
dc.contributor.authorSchlager, H.
dc.contributor.authorSihler, H.
dc.contributor.authorTheys, N.
dc.contributor.authorVan Roozendael, M.
dc.contributor.authorWagner, T.
dc.contributor.authorPfeilsticker, K.
dc.date2011
dc.date.accessioned2016-03-29T12:43:53Z
dc.date.available2016-03-29T12:43:53Z
dc.identifier.urihttps://orfeo.belnet.be/handle/internal/3117
dc.descriptionA novel limb scanning mini-DOAS spectrometer for the detection of UV/vis absorbing radicals (e.g., O3, BrO, IO, HONO) was deployed on the DLR-Falcon (Deutsches Zentrum für Luft- und Raumfahrt) aircraft and tested during the ASTAR 2007 campaign (Arctic Study of Tropospheric Aerosol, Clouds and Radiation) that took place at Svalbard (78° N) in spring 2007. Our main objectives during this campaign were to test the instrument, and to perform spectral and profile retrievals of tropospheric trace gases, with particular interest on investigating the distribution of halogen compounds (e.g., BrO) during the so-called ozone depletion events (ODEs). In the present work, a new method for the retrieval of vertical profiles of tropospheric trace gases from tropospheric DOAS limb observations is presented. Major challenges arise from modeling the radiative transfer in an aerosol and cloud particle loaded atmosphere, and from overcoming the lack of a priori knowledge of the targeted trace gas vertical distribution (e.g., unknown tropospheric BrO vertical distribution). Here, those challenges are tackled by a mathematical inversion of tropospheric trace gas profiles using a regularization approach constrained by a retrieved vertical profile of the aerosols extinction coefficient EM. The validity and limitations of the algorithm are tested with in situ measured EM, and with an absorber of known vertical profile (O4). The method is then used for retrieving vertical profiles of tropospheric BrO. Results indicate that, for aircraft ascent/descent observations, the limit for the BrO detection is roughly 1.5 pptv (pmol mol−1), and the BrO profiles inferred from the boundary layer up to the upper troposphere and lower stratosphere have around 10 degrees of freedom. For the ASTAR 2007 deployments during ODEs, the retrieved BrO vertical profiles consistently indicate high BrO mixing ratios (∼15 pptv) within the boundary layer, low BrO mixing ratios (≤1.5 pptv) in the free troposphere, occasionally enhanced BrO mixing ratios (∼1.5 pptv) in the upper troposphere, and increasing BrO mixing ratios with altitude in the lowermost stratosphere. These findings agree reasonably well with satellite and balloon-borne soundings of total and partial BrO atmospheric column densities.
dc.languageeng
dc.titleAirborne DOAS limb measurements of tropospheric trace gas profiles: Case studies on the profile retrieval of O 4 and BrO
dc.typeArticle
dc.subject.frascatiEarth and related Environmental sciences
dc.audienceScientific
dc.subject.freeaircraft
dc.subject.freealgorithm
dc.subject.freeatmospheric chemistry
dc.subject.freeballoon observation
dc.subject.freecloud radiative forcing
dc.subject.freehalogen
dc.subject.freemixing ratio
dc.subject.freeozone
dc.subject.freeradiative transfer
dc.subject.freeradical
dc.subject.freespatiotemporal analysis
dc.subject.freespectrometer
dc.subject.freestratosphere-troposphere interaction
dc.subject.freetrace gas
dc.subject.freeultraviolet radiation
dc.subject.freevertical profile
dc.subject.freevisible spectrum
dc.subject.freeArctic
dc.subject.freeSvalbard
dc.subject.freeSvalbard and Jan Mayen
dc.subject.freeFalconidae
dc.source.titleAtmospheric Measurement Techniques
dc.source.volume4
dc.source.issue6
dc.source.page1241-1260
Orfeo.peerreviewedYes
dc.identifier.doi10.5194/amt-4-1241-2011
dc.identifier.scopus2-s2.0-80052691138


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