Mesoscale Modelling for Tropical Cyclone Forecasting over the North Indian Ocean - Monitoring and Prediction of Tropical Cyclones in the Indian Ocean and Climate Change - page 270

2012b). Studies such as Gao et al. (1999) and Xiao et al. (2007) showed
improvement in the simulation of mesoscale events with assimilation of Doppler
weather radar (DWR) data.
The main objective of this study is to evaluate the impact of assimilation
of different sources of observations into the initial conditions of customized
ARW and Non-hydrostatic mesoscale model (NMM) of Weather Research and
Forecasting (WRF) over the NIO. The section 2 describes models configuration,
while section 3 provides results and discussion and finally section 4 gives
broad conclusions of the study.
2. Models Configuration
In this section, a brief description of both ARW and NMM modelling systems
are illustrated.
2.1 ARW Model
The single domain is fixed to 3º N-28º N, 78º E-103º E, centered at 15.5º N
and 89.5º E for BoB TCs and 5º N-30º N, 48º E-78º E with centre at 17.5º N
and 63º E for AS TCs. The model follows Arakawa C-grid staggering. ARW
model is customized for NIO basin and it has shown better performance in the
real time prediction of 2008 cyclones (Osuri et al., 2012a). ARW model follows
Kain-Fristch convection scheme, Yonsei University (YSU) planetary boundary
layer (PBL) scheme, WRF single-moment 3-class (WSM3) microphysics
scheme, Monin-Obukhov surface scheme, thermal diffusion land-surface
scheme and the Rapid Radiative Transfer Model (RRTM) for long wave and
Goddard for short wave atmospheric radiation schemes.
2.2 NMM Model
The WRF-NMM is a fully compressible, state-of-the-art, Eulerian non-
hydrostatic model with a hydrostatic option (Janjic, 2001, 2003a, 2003b). The
horizontal rotated latitude-longitude coordinate and the vertical terrain-
following hybrid sigma-pressure coordinate system is used. The NMM
model is integrated in a single domain with the horizontal resolution of 9 km
covering the domain 3º N-28º N, 78º E-103º E for BoB TCs and 8º N-28º N,
55º E-75º E for AS TC. The model has 51 levels up to a height of 30 km in the
vertical and the model is integrated with time step of 20 sec. The optimum
combination of the physical parameterization schemes (Pattanayak et al., 2012)
in simulation of TCs over NIO is used in this study. The combination of
Simplified Arakawa Schubert (SAS) cumulus convection, YSU PBL, NMM
land surface physics, Ferrier microphysics and the GFDL long wave/short wave
radiation schemes is the optimum configuration for the simulation/prediction
of tropical cyclones over NIO. The brief description of both ARW and NMM
models are illustrated in Table 1.