Four-year long-path monitoring of ambient aerosol extinction at a central European urban site: Dependence on relative humidity

dc.bibliographicCitation.firstPage1863eng
dc.bibliographicCitation.issue4eng
dc.bibliographicCitation.lastPage1876eng
dc.bibliographicCitation.volume16
dc.contributor.authorSkupin, A.
dc.contributor.authorAnsmann, A.
dc.contributor.authorEngelmann, R.
dc.contributor.authorSeifert, P.
dc.contributor.authorMüller, T.
dc.date.accessioned2017-09-16T03:58:26Z
dc.date.available2019-06-26T17:22:46Z
dc.date.issued2016
dc.description.abstractThe ambient aerosol particle extinction coefficient is measured with the Spectral Aerosol Extinction Monitoring System (SÆMS) along a 2.84 km horizontal path at 30–50 m height above ground in the urban environment of Leipzig (51.3° N, 12.4° E), Germany, since 2009. The dependence of the particle extinction coefficient (wavelength range from 300 to 1000 nm) on relative humidity up to almost 100 % was investigated. The main results are presented. For the wavelength of 550 nm, the mean extinction enhancement factor was found to be 1.75 ± 0.4 for an increase of relative humidity from 40 to 80 %. The respective 4-year mean extinction enhancement factor is 2.8 ± 0.6 for a relative-humidity increase from 40 to 95 %. A parameterization of the dependency of the urban particle extinction coefficient on relative humidity is presented. A mean hygroscopic exponent of 0.46 for the 2009–2012 period was determined. Based on a backward trajectory cluster analysis, the dependence of several aerosol optical properties for eight air flow regimes was investigated. Large differences were not found, indicating that local pollution sources widely control the aerosol conditions over the urban site. The comparison of the SÆMS extinction coefficient statistics with respective statistics from ambient AERONET sun photometer observations yields good agreement. Also, time series of the particle extinction coefficient computed from in situ-measured dry particle size distributions and humidity-corrected SÆMS extinction values (for 40 % relative humidity) were found in good overall consistency, which verifies the applicability of the developed humidity parameterization scheme. The analysis of the spectral dependence of particle extinction (Ångström exponent) revealed an increase of the 390–881 nm Ångström exponent from, on average, 0.3 (at 30 % relative humidity) to 1.3 (at 95 % relative humidity) for the 4-year period.eng
dc.description.versionpublishedVersioneng
dc.formatapplication/pdf
dc.identifier.urihttps://doi.org/10.34657/970
dc.identifier.urihttps://oa.tib.eu/renate/handle/123456789/961
dc.language.isoengeng
dc.publisherMünchen : European Geopyhsical Unioneng
dc.relation.doihttps://doi.org/10.5194/acp-16-1863-2016
dc.relation.ispartofseriesAtmospheric Chemistry and Physics, Volume 16, Issue 4, Page 1863-1876eng
dc.rights.licenseCC BY 3.0 Unportedeng
dc.rights.urihttps://creativecommons.org/licenses/by/3.0/eng
dc.subjectAERONETeng
dc.subjectaerosoleng
dc.subjectaerosol propertyeng
dc.subjectextinction coefficienteng
dc.subjectmonitoring systemeng
dc.subjectphotometereng
dc.subjectrelative humidityeng
dc.subjecturban areaeng
dc.subject.ddc550eng
dc.titleFour-year long-path monitoring of ambient aerosol extinction at a central European urban site: Dependence on relative humidityeng
dc.typearticleeng
dc.typeTexteng
dcterms.bibliographicCitation.journalTitleAtmospheric Chemistry and Physicseng
tib.accessRightsopenAccesseng
wgl.contributorTROPOSeng
wgl.subjectGeowissenschafteneng
wgl.typeZeitschriftenartikeleng
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