Ww. Grabowski et Mw. Moncrieff, Large-scale organization of tropical convection in two-dimensional explicit numerical simulations, Q J R METEO, 127(572), 2001, pp. 445-468
Citations number
45
Categorie Soggetti
Earth Sciences
Journal title
QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY
The large-scale organization of tropical deep convection is investigated in
idealized two-dimensional cloud-resolving simulations. A 20 000 km periodi
c computational domain allows interactions among moist convection, mesoscal
e organization, and surface exchange on a wide range of scales. A uniform 1
0 m s(-1) easterly wind and a uniform sea surface temperature of 30 C are a
ssumed. A prescribed temperature tendency mimicking the mean radiative cool
ing of the tropical troposphere is used in this pilot study. The large-scal
e organization of convection resembles the observed tropical atmosphere as
well as results from some previous numerical studies using parametrized con
vection. The simulation highlights mesoscale convective systems with horizo
ntal scales of several hundred kilometres moving east to west with speeds s
imilar to the mean flow, and an envelope of convection with a horizontal ex
tent of a few thousand kilometres and propagating west to east. The propaga
tion speed of the large-scale envelope compares well with the phase velocit
ites of convectively coupled Kelvin waves observed in the equatorial wavegu
ide. Convective momentum transport and the impact of convective systems on
temperature and moisture near the surface are key processes responsible for
the large-scale organization of convection. These results are discussed in
the context of recent observations and numerical studies of convection org
anization in the tropics.