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dc.contributor.authorSeifert, P.
dc.contributor.authorAnsmann, A.
dc.contributor.authorMueller, D.
dc.contributor.authorWandinger, U.
dc.contributor.authorAlthausen, D.
dc.contributor.authorHeymsfield, A. J.
dc.contributor.authorMassie, S. T.
dc.contributor.authorSchmitt, C.
dc.date.accessioned2013-08-01T10:18:05Z
dc.date.available2013-08-01T10:18:05Z
dc.date.issued2007-09-14
dc.identifier.citationSeifert , P , Ansmann , A , Mueller , D , Wandinger , U , Althausen , D , Heymsfield , A J , Massie , S T & Schmitt , C 2007 , ' Cirrus optical properties observed with lidar, radiosonde, and satellite over the tropical Indian Ocean during the aerosol-polluted northeast and clean maritime southwest monsoon ' , Journal of Geophysical Research: Atmospheres , vol. 112 , no. D17 , D17205 . https://doi.org/10.1029/2006JD008352
dc.identifier.issn2169-897X
dc.identifier.otherPURE: 1980757
dc.identifier.otherPURE UUID: 842db817-415f-434b-b040-dc055c4f8696
dc.identifier.otherWOS: 000249518800003
dc.identifier.otherScopus: 35748950139
dc.identifier.otherORCID: /0000-0002-0203-7654/work/68611610
dc.identifier.urihttp://hdl.handle.net/2299/11268
dc.description.abstractCirrus formation and geometrical and optical properties of tropical cirrus as a function of height and temperature are studied on the basis of INDOEX ( Indian Ocean Experiment) lidar and radiosonde measurements and satellite observations of deep convection causing the generation of anvil cirrus. Lidar and radiosonde measurements were conducted at Hulule ( 4.1 degrees N, 73.3 degrees E), Maldives, during four field campaigns carried out in February March 1999 and March 2000 ( northeast ( NE) monsoon season, characterized by increased concentrations of anthropogenic aerosols over the Indian Ocean) and in July and October 1999 ( southwest ( SW) monsoon season, characterized by clean maritime conditions). As a result of a stronger impact of deep convection on cirrus formation during the SW monsoon season, cirrus clouds covered the sky over the lidar site in only 35% ( NE), but 64% ( SW) of the measurement time. Subvisible cirrus ( optical depth = 0.3) were observed in 18%, 48%, and 34% ( NE) and in 8%, 52%, and 40% ( SW) out of all cirrus cases, respectively. Mean midcloud heights were rather similar with values of 12.9 +/- 1.5 km ( NE) and 12.7 +/- 1.3 km ( SW). In 25% of the cases the cirrus top height was found close to the tropopause. Mean values of the multiple- scattering- corrected cirrus optical depth, cirrus layer mean extinction coefficient, and extinction- to- backscatter ratio were 0.25 +/- 0.26 ( NE) and 0.34 +/- 0.29 ( SW), 0.12 +/- 0.09 km(-1) ( NE) and 0.12 +/- 0.10 km(-1) ( SW), and 33 +/- 9 sr ( NE) and 29 +/- 11 sr ( SW), respectively. A functional dependency of the extinction coefficient of the tropical cirrus on temperature is presented. All findings are compared with several other cirrus lidar observations in the tropics, subtropics, and at midlatitudes. By contrasting the cirrus optical properties of the different seasons, a potential impact of anthropogenic particles on anvil cirrus optical properties was examined. Differences in the cirrus extinction- to- backscatter ratio suggest that NE monsoon anvil cirrus originating from deep- convection cumulus clouds had more irregularly shaped and thus slightly larger ice crystals than respective SW monsoon anvil cirrus. Because the meteorological conditions were found to vary significantly between the seasons, an unambiguous identification of the influence of Asian haze on cirrus optical properties is not possible.en
dc.format.extent14
dc.language.isoeng
dc.relation.ispartofJournal of Geophysical Research: Atmospheres
dc.subjectRAMAN
dc.subjectSCATTERING
dc.subjectCLOUD CLIMATOLOGY
dc.subjectRADIATIVE PROPERTIES
dc.subjectICE PARTICLES
dc.subjectMICROPHYSICAL PROPERTIES
dc.subjectTROPOPAUSE
dc.subjectPARTICLE PROPERTIES
dc.subjectCOLD CIRRUS
dc.subjectEQUATORIAL CIRRUS
dc.titleCirrus optical properties observed with lidar, radiosonde, and satellite over the tropical Indian Ocean during the aerosol-polluted northeast and clean maritime southwest monsoonen
dc.contributor.institutionCentre for Atmospheric and Climate Physics Research
dc.contributor.institutionSchool of Physics, Engineering & Computer Science
dc.contributor.institutionDepartment of Physics, Astronomy and Mathematics
dc.description.statusPeer reviewed
rioxxterms.versionofrecordhttps://doi.org/10.1029/2006JD008352
rioxxterms.typeJournal Article/Review
herts.preservation.rarelyaccessedtrue


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