HR: 0800h
AN: A21E-0769    [Abstracts]
TI: A numerical study of tropical cross-tropopause transport by convective overshoots
AU: Mascart, P J
EM: Patrick.Mascart@aero.obs-mip.fr
AF: University of Toulouse, Laboratoire d'Aerologie, OMP 14 avenue Belin, Toulouse, 31400, France
AU: * Chaboureau, J
EM: Jean-Pierre.Chaboureau@aero.obs-mip.fr
AF: University of Toulouse, Laboratoire d'Aerologie, OMP 14 avenue Belin, Toulouse, 31400, France
AB: Observations obtained during the Tropical Convection, Cirrus and Nitrogen Oxides (TROCCINOX) golden day have revealed the presence of ice particles up to 410 K (18.2 km) 2 km above the local tropopause. The case was investigated using a three-dimensional quadruply nested non-hydrostatic simulation and Meteosat Second Generation (MSG) observations. The simulation reproduced the measurements along the flight track fairly well. A reasonable agreement with MSG observations was also achieved: the 10.8-micron brightness temperature (BT) minimum of 187 K was reproduced (a value 6 K colder than the environmental cold-point temperature) as was the positive BT difference between the 6.2- and 10.8-micron bands, an overshoot signature. The simulation produced several overshooting plumes up to 410 K yielding an upward transport of water vapour of a few tons per second across the tropical tropopause. The estimated mass flux agrees with those derived from over tracer budgets, indicating that convection transports mass across the tropopause.
UR: http://mesonh.aero.obs- mip.fr/chaboureau/PUB
DE: 3334 Middle atmosphere dynamics (0341, 0342)
DE: 3362 Stratosphere/troposphere interactions
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting