Simulation of Bay of Bengal Cyclones using
Mesoscale Models
U.
C. Mohanty
Centre for
Atmospheric Sciences IIT
Abstract:
The Bay of
Bengal tropical cyclone disaster is the costliest and deadliest natural
hazard in Indian sub-continent. It has significant socio-economic
impact on the countries bordering the Bay of Bengal, in particular,
India, Bangladesh and Mayanmar. Timely and reasonably accurate
prediction of track and intensity of these storms can save loss of
lives and reduce damage to properties.
The genesis and movement of the Bay of Bengal tropical cyclones are
unique in nature compare to other region of cyclones. The high
resolution mesoscale model MM5 is extensively tested over the basin
with different parameterization schemes and different model horizontal
resolution. The optimal configuration of the model with improved
initial condition through vortex initialization and assimilation of
satellite data is used to simulate all severe cyclonic storms (eight)
over the Bay of Bengal during the period 1995-1999. The simulation
results of these storms are illustrated with performance/forecast skill
of the model. The intensity of the storms both in terms of central sea
level pressure and strength of maximum wind is simulated with
reasonable accuracy. The model simulated track of the storms followed
the observed track closely and track forecast errors indicate
reasonably good accuracy of the model.
Recently developed Hurricane Weather Research and Forecast (HWRF) model
by NCEP is adopted over the Bay of Bengal region. The HWRF model is
tested with the recently occurred tropical cyclone MALA in the Bay of
Bengal. The model simulated track and intensity of the storm are
compared with operational model forecasts of IMD and UKMO. The
performance of the forecast skill of the HWRF model is appreciably
better in this case. However, the model will extensively test in all
eight sever cyclonic storms over the Bay of Bengal during the period
1995-1999 to evaluate performance of the model.