Kurihara, Y., and R. E. Tuleya, 1974: Structure of a tropical cyclone developed in a three-dimensional numerical simulation model. Journal of the Atmospheric Sciences, 31 (4), 893-919.
Abstract: A three-dimensional, 11-level, primitive equation model has been constructed
for a simulation study of tropical cyclones. The model has four levels in
the boundary layer and its 70 x 70 variable grid mesh encloses a 4000-km
square domain with a 20-km resolution near the center. Details of the model,
including the parameterization scheme for the subgrid-scale diffusion and
convection processes, are described.
A weak vortex in the conditionally unstable tropical atmosphere is given
as the initial state for a numerical integration from which a tropical cyclone
develops in the model. During the integration period of one week, the sea
surface temperature is fixed at 302K.
The central surface pressure drops to about 940 mb, while a warm moist
core is established. The azimuthal component of mean horizontal wind is
maximum at about 60 km from the center at all levels. A strong inflow is
observed in the boundary layer. At upper levels, a secondary radial-vertical
circulation develops in and around the region of negative mean absolute
vorticity. In the same region, the azimuthal perturbation of horizontal
wind is pronounced. At the mature stage, the domain within 500 km radius
is supplied with kinetic energy for asymmetric flow by both barotropic and
baroclinic processes. At 60 km radius, the temperature perturbation field
is maintained by condensation-convection heating at upper levels and by
adiabatic temperature change due to vertical motion at lower levels. An
area having an eye-like feature is found off the pressure center.
Structure of spiral bands in the outer region is extensively analyzed.
The phase relationship among the pressure, horizontal motion, vertical motion,
temperature and moisture fields is discussed. The spiral band behaves like
an internal gravity wave. Once the band is formed in an area surrounding
the center, it propagates outward apparently without appreciable further
supply of energy, as far as the present case is concerned.