J.-L Redelsperger1, P. R. A. Brown2, F. Guichard1, C. Hoff1, M. Kawasima3, S. Lang4, T. Montmerle5, K. Nakamura6, K. Saito7, C. Seman8, W.-K. Tao4 and L. J. Donner8
1CNRM /GAME( CNRS & Météo-France),
Toulouse, France
2UK Met Office/JCMM, Reading, United Kingdom
3ILTS, Sapporo, Japan
4GSFC, Greenbelt, USA
5CETP, Velizy, France
6ORI, Tokyo, Japan
7MRI, Tsukuba, Japan
8GFDL, Princeton, USA
Quarterly Journal of the Royal Meteorological Society, 2000, vol. 126, pp. 823-864.
Summary: Results from 8 CloudResolving models are compared
for the first time for the case of an oceanic tropical squall line observed
during TOGA COARE. There is broad agreement between all the models
in describing the overall structure and propagation of the squall line
and some quantitative agreement in the evolution of rainfall. There is
also a more qualitative agreement between models in describing the vertical
structure of the apparent heat and moisture sources. 3D experiments with
an active ice phase and open lateral boundary conditions along the direction
of system propagation show good agreement for all parameters. The comparison
of 3D simulated fields with those obtained from two different analyses
of airborne Doppler radar data indicates that the 3D models are able to
simulate its dynamical structure. The doublepeaked updraft structure
observed by Doppler radar is thus simulated. The second peak around 10
km in height is obtained only when the ice phase is represented. 2D simulations
with an ice phase parameterization also exhibit this structure although
with a larger temporal variability. In 3D simulations, the evolution of
the mean wind profile is in the sense of decreasing the shear. 2D simulations
are unable to reproduce this behaviour.