6533b856fe1ef96bd12b1d66
RESEARCH PRODUCT
Dehydration potential of ultrathin clouds at the tropical tropopause
Leopoldo StefanuttiHeini WernliAxel ThomasG. Di DonfrancescoJohan StrömStephan FueglistalerChristoph KiemleV. RudakovC. M. VolkStephan BorrmannAlberto AdrianiB. P. LuoV. KhattatovV. SantacesariaHarald FlentjeVladimir YushkovKenneth S. CarslawThomas PeterMartin WirthThomas TrautmannR. MackenzieValentin MitevGuido TociJ. BeuermannP. MazzinghiCornelius SchillerFrancesco CairoKevin J. Noonesubject
Ice cloudMaterials scienceIce crystalsparticle micro-physicsdehydrationtropical tropopauseRadiusAtmospheric sciencesJTroposphereGeophysicsAltitudeddc:550General Earth and Planetary SciencesCirrussubvisible cirrus cloudsTropopauseStratospheredescription
[1] We report on the first simultaneous in situ and remote measurements of subvisible cirrus in the uppermost tropical troposphere. The observed cirrus, called UTTCs ( ultrathin tropical tropopause clouds), are the geometrically (200-300 m) and optically (t approximate to 10(-4)) thinnest large-scale clouds ever sampled (approximate to10(5) km(2)). UTTCs consist of only a few ice particles per liter with mean radius approximate to5 mum, containing only 1-5 % of the total water. Yet, brief adiabatic cooling events only 1-2 K below mean ambient temperature destabilize UTTCs, leading to large sedimenting particles (r approximate to 25 mm). Due to their extreme altitude above 17 km and low particle number density, UTTCs may efficiently dehydrate air during its last encounter with the ice phase before entering the stratosphere.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2003-01-01 |