Bender, M. A., I. Ginis, and Y. Kurihara, 1993: Numerical simulations
of tropical cyclone-ocean interaction with a high-resolution coupled model.
Journal of Geophysical Research, 98(D12), 23,245-23,263.
Abstract: The tropical cyclone-ocean interaction was investigated
using a high-resolution tropical cyclone ocean coupled model. The model
design consisted of the NOAA Geophysical Fluid Dynamics Laboratory tropical
cyclone prediction model which was coupled with a multilayer primitive
equation ocean model. Coupling between the hurricane and the ocean models
was carried out by passing into the ocean model the wind stress, heat,
and moisture fluxes computed in the hurricane model. The new sea surface
temperature (SST) calculated by the ocean model was then used in the tropical
cyclone model. A set of idealized numerical experiments were performed
in which a tropical cyclone vortex was embedded in both easterly and westerly
basic flows of 2.5, 5, and 7.5 m s-1 with
a fourth experiment run with no basic flow specified initially. The profile
of the trangential wind for Hurricane Gloria at 1200 UTC 22, September
1985 was used as the initial condition of the tropical cyclone for each
of the experiments. The model ocean was initially horizontally homogenous
and quiescent. To clarify the impact of the ocean response to the hurricane's
behavior, analogous experiments were also carried out with the SST kept
constant (control cases). The experiments indicated that the cooling of
the sea surface induced by the tropical cyclone resulted in a significant
impact on the ultimate storm intensity due to the reduction of total heat
flux directed into the tropical cyclone above the regions of decreased
SST. The sea surface cooling produced by the tropical cyclones was found
to be larger when the storms moved slower. In the experiments run without
an initial basic flow,the maximum SST anomaly was about -5.6°C
with a resulting difference in the minimum sea level pressure and maximum
surface winds of 16.4 hPa and -7 m s-1,
respectively. In contrast, in the experiments run with the 7.5 ms-1
basic flow, the maximum SST anomalies ranged from about 2.6° to
3.0°C with a difference in the minimum sea level pressure and maximum
surface winds of about 7.3 hPa and -2.7 m s-1.
The tropical cyclone-ocean coupling significantly influenced the storm
track only for the case with no basic flow and the 2.5 m s-1
easterly flow. In these cases the storm with the ocean interaction turned
more to the north and east (no basic flow) or the north (2.5 m s-1
easterly flow) of the experiments with constant SST. In the first case,
the storm by 72 hours was located over 70 km to the east-southeast of the
control case. A possible explanation for this track deviation is related
to a systematic weakening of the mean tangential flow at all radii of the
storm due to the interaction with the ocean and resulting alteration of
the beta drift.