Sumam, Mary Idicula; Mohanty, U C; Litta, A J(Indian Academy of Sciences, April , 2012)
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Abstract:
Thunderstorm, resulting from vigorous convective activity, is one of the most spectacular weather phenomena
in the atmosphere. A common feature of the weather during the pre-monsoon season over the
Indo-Gangetic Plain and northeast India is the outburst of severe local convective storms, commonly
known as ‘Nor’westers’(as they move from northwest to southeast). The severe thunderstorms associated
with thunder, squall lines, lightning and hail cause extensive losses in agricultural, damage to structure
and also loss of life. In this paper, sensitivity experiments have been conducted with the Non-hydrostatic
Mesoscale Model (NMM) to test the impact of three microphysical schemes in capturing the severe thunderstorm
event occurred over Kolkata on 15 May 2009. The results show that the WRF-NMM model
with Ferrier microphysical scheme appears to reproduce the cloud and precipitation processes more realistically
than other schemes. Also, we have made an attempt to diagnose four severe thunderstorms that
occurred during pre-monsoon seasons of 2006, 2007 and 2008 through the simulated radar reflectivity
fields from NMM model with Ferrier microphysics scheme and validated the model results with Kolkata
Doppler Weather Radar (DWR) observations. Composite radar reflectivity simulated by WRF-NMM
model clearly shows the severe thunderstorm movement as observed by DWR imageries, but failed to
capture the intensity as in observations. The results of these analyses demonstrated the capability of
high resolution WRF-NMM model in the simulation of severe thunderstorm events and determined that
the 3 km model improve upon current abilities when it comes to simulating severe thunderstorms over
east Indian region
Description:
J. Earth Syst. Sci. 121, No. 2, April 2012, pp. 297–316