Role of Sea Surface Temperature in Simulation of Arabian Sea Cyclone - Monitoring and Prediction of Tropical Cyclones in the Indian Ocean and Climate Change - page 334

coordinates are present. Model sigma coordinates are closer in the Planetary
Boundary Layer (PBL) (below 850 hPa) and seven sigma coordinates are present
at the surface layer. This is a primitive equation model and the equations are
solved in an Arakawa B grid. For the model integration, leapfrog time integration
scheme with time splitting is used. Several physical parameterization schemes
like PBL, cumulus, and microphysics parameterization schemes are present in
the model to take account of the physical processes. A number of studies have
been carried out to evaluate the skill of this model in simulating TCs (Mandal
et al., 2004; Ali et al., 2007) and found that the performance of this model is
satisfactory. A detailed description of the model is available in Dudhia (1993)
and Grell et al. (1995). The overview of the model used in this study is shown
in Table 1.
The Arabian Sea (AS) cyclone formed during May 2002, has an unusual
westward movement and damaged huge properties in the Oman. A low pressure
system is formed at 8.6°N/ 67.7°E on May 5, 2002 (at 18 UTC). On May 6,
this system intensifies from low pressure to deep depression and the storm is
located at 10.3°N/66.0°E which is a few hundred miles away in the west-
northwest of Maldives. The storm has a west-northwestwards movement as
deep depressions and reaches at the location 13.8°N/59.6°E till 18 UTC of 8
May. The system further intensifies and becomes cyclonic storm on May 9.
This cyclonic storm maintains its intensity till the landfall near Salalah, Oman
on 10 May. The system weakens rapidly after crossing the land at 09 UTC and
almost dissipates around the end of the same day i.e. May 10.

Table 1: Overview of the MM5 mesoscale model used in the present study

Dynamics Non-hydrostatic

Model domain 10°S-30°N, 60°E-110°E

Horizontal grid distance 30 km

Integration time step 45 s

Map projection Mercator

Horizontal grid system Arakawa B-grid

Vertical co-ordinates Terrain-following sigma co-ordinates, 23 sigma

levels (seven within boundary layer)

Time integration scheme Leapfrog scheme (with time split technique)

Spatial differencing scheme Second order centered

Lateral boundary condition Relaxation

Top boundary condition Rigid lid

Radiation parameterization NCAR CCM2 radiation scheme

Surface layer parameterization Multi-layer soil model

Cumulus parameterization Grell

PBL parameterization NCEP MRF

Microphysics Hsie's warm rain scheme