Sinlung /
21 March 2011

‘Recce' of Northeast Over For Study Of Deadly Thunderstorms

By Vinson Kurian

Thiruvananthapuram, Mar 21 :  Even as heavy to very heavy thundershowers are pounding Cherrapunji in Assam, India Meteorological Department (IMD) and India Space Research Organisation (ISRO) will launch a combined experiment to track seasonal thunderstorms in east and northeast India.

Cherrapunji saw an exceptional 46 cm of rain being recorded overnight on Sunday morning while the previous day's figure stood at 32 cm.

PILOT INITIATIVE

A pilot initiative to track thunderstorms has been on form last year, according to Dr P. V. Joseph, renowned meteorologist and a former director of IMD. The meteorological parameters need to be checked and analysed to see whether the Cherrapunji events heralds the beginning of the annual thunderstorm season.

Meanwhile, the nationally coordinated programme is being called ‘Severe Thunderstorm Observation and Regional Modelling (STORM).'

Dr Joseph would lead a dedicated team of experts in the experiment to be carried out from its base at IIT-Kharagpur from April 15. This is a comprehensive observational and modelling effort to improve understanding and prediction of severe thunderstorms.

Thus the proposed programme is expected to improve both understanding and prediction of these local storms, Dr Joseph told Business Line. An elaborate plan to track thunderstorm development has been laid out, which has seen the deployment of sophisticated instruments in the entire northeast.

The IMD alone has set up 300 automatic weather gauges while ISRO has lined up another 100. This would facilitate a study of surface conditions at close intervals. The Doppler Radar at Kolkata and a counterpart coming up at Guwahati, apart from a fleet of mobile Doppler radars, would help track the storms down. According to Dr Joseph, the experiment would be equipped to study the inside of a thunderstorm and look at the cloud from various angles.

“TINDER BOX”

Hot and dry northwest to southeast winds flow in a southeast direction over the plains of northwest India towards east and northeast India and confronts moisture-laden easterlies from the Bay of Bengal. This sets up ‘tinder box' conditions, fuelling intense convection to spark thunder, lightning and heavy to very heavy localised showers, which are seasonal in nature.

Hail-storms, dust-storms, surface wind squalls, down-bursts and tornadoes also get thrown up in the process, which can cause heavy damage to life and property. During the pre-monsoon season of April and May, north India witnesses severe thunderstorms.

SEVERE DAMAGE

Downsteam to the east and southeast, Gangetic West Bengal and surrounding areas also get severe thunderstorms called Nor'westers, locally called Kal Baisakhi. Northwest India gets convective dust storms, called locally andhi.

Severe thunderstorms create lot of damage to property and standing crops. The strong surface wind squalls, large hail and occasional tornadoes accompanying them cause human and animal fatalities. They also pose serious hazards to aviation activities.

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