Variability of cirrus clouds in a convective outflow during the Hibiscus campaign
Résumé
Light-weight microlidar and water vapour measurements
were taken on-board a stratospheric balloon during
the HIBISCUS 2004 campaign, held in Bauru, Brazil
(49W, 22 S). Cirrus clouds were observed throughout the
flight between 12 and 15 km height with a high mesoscale
variability in optical and microphysical properties. It was
found that the cirrus clouds were composed of different layers
characterized by marked differences in height, thickness
and optical properties. Simultaneous water vapour observations
show that the different layers are characterized by
different values of the saturation with respect to ice. A
mesoscale simulation and a trajectory analysis clearly revealed
that the clouds had formed in the outflow of a large
and persistent convective region and that the observed variability
of the optical properties and of the cloud structure
is likely linked to the different residence times of the
convectively-processed air in the upper troposphere.
Origine : Fichiers éditeurs autorisés sur une archive ouverte
Licence : CC BY - Paternité
Licence : CC BY - Paternité
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