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Case study of a tropopause fold and of subsequent mixing in the subtropics of the Southern Hemisphere

dc.contributor.authorGouget, H.
dc.date2000
dc.date.accessioned2017-05-05T12:33:42Z
dc.date.available2017-05-05T12:33:42Z
dc.identifier.urihttps://orfeo.belnet.be/handle/internal/5335
dc.descriptionAircraft measurements of ozone, methane, carbon monoxide, relative humidity and equivalent potential temperature were performed during the TROPOZ II campaign. During the descent down to Buenos Aires (34°S, 58°W) at 19:00 UTC on 22 January 1991, a double-peaked layer of elevated ozone was observed. Both a physico-chemical interpretation of each peak and diagnoses based on potential vorticity and ageostrophic circulations indicate the stratospheric origin of the ozone maxima. The relative minimum of ozone and significant increase of relative humidity present in the shallow layer between the peaks, in a region of wind shear, is identified as the signature of real mixing. This intermediate layer shows that ozone originating in the stratosphere was subsequently mixed into the troposphere by folding processes associated with the jet. This result suggests the relative importance of stratosphere-troposphere exchanges to the ozone budget in the Southern Hemisphere, due to a lesser extent of anthropogenic sources in this hemisphere. Copyright (C) 2000 Elsevier Science B.V.Aircraft measurements of ozone, methane, carbon monoxide, relative humidity and equivalent potential temperature were performed during the TROPOZ II campaign. During the descent down to Buenos Aires (34°S, 58°W) at 19:00 UTC on 22 January 1991, a double-peaked layer of elevated ozone was observed. Both a physico-chemical interpretation of each peak and diagnoses based on potential vorticity and ageostrophic circulations indicate the stratospheric origin of the ozone maxima. The relative minimum of ozone and significant increase of relative humidity present in the shallow layer between the peaks, in a region of wind shear, is identified as the signature of real mixing. This intermediate layer shows that ozone originating in the stratosphere was subsequently mixed into the troposphere by folding processes associated with the jet. This result suggests the relative importance of stratosphere-troposphere exchanges to the ozone budget in the Southern Hemisphere, due to a lesser extent of anthropogenic sources in this hemisphere.
dc.languageeng
dc.titleCase study of a tropopause fold and of subsequent mixing in the subtropics of the Southern Hemisphere
dc.typeArticle
dc.subject.frascatiPhysical sciences
dc.audienceScientific
dc.subject.freeAtmospheric chemistry
dc.subject.freeAtmospheric composition
dc.subject.freeAtmospheric humidity
dc.subject.freeAtmospheric movements
dc.subject.freeAtmospheric temperature
dc.subject.freeCarbon monoxide
dc.subject.freeMethane
dc.subject.freeOzone
dc.subject.freeTropics
dc.subject.freeTroposphere
dc.subject.freeUpper atmosphere
dc.subject.freeVortex flow
dc.subject.freeEquivalent potential temperature
dc.subject.freeStratosphere-troposphere exchanges (STE)
dc.subject.freeTropopause
dc.subject.freeAir pollution
dc.subject.freeozone
dc.subject.freeatmospheric dynamics
dc.subject.freefold
dc.subject.freemixing
dc.subject.freeSouthern Hemisphere
dc.subject.freesubtropical region
dc.subject.freetropopause
dc.subject.freeArgentina
dc.subject.freearticle
dc.subject.freehumidity
dc.subject.freemeteorology
dc.subject.freeozone layer
dc.subject.freepriority journal
dc.subject.freestratosphere
dc.subject.freetemperature
dc.subject.freetroposphere
dc.source.titleAtmospheric Environment
dc.source.volume34
dc.source.issue16
dc.source.page2653-2658
Orfeo.peerreviewedYes
dc.identifier.doi10.1016/S1352-2310(99)00508-7
dc.identifier.scopus2-s2.0-0034079172


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