CU to help weather thunderstorms

Mou Chakraborty
Kolkata, March 23, 2007
Predicting the occurrence of thunderstorms that wreak havoc in the land, especially to farmers, has been a bone of contention among weather scientists. Now, experts promise to do just using sophisticated radar systems.
Severe afternoon thunderstorms, called kalbaisakhis or nor’westers have caused disaster on the eastern Gangetic plains since time immemorial. Now, under the programme — Severe Thunderstorms: Observation and Regional Modelling (STORM), Calcutta University (CU) has purchased a special radar which can study the nor’wester clouds and help meteorologists to predict the locality, time and intensity of the storms accurately.
STORM, a nationally coordinated programme was launched on April 15, 2006 and is being done jointly conducted by CU, IIT Kharagpur, regional metrology department, Indian Air Force and DST.
CU has purchased a mobile Doppler radar, which will chase the nor’wester cloud from the time of its origin. The radar costing over a crore can cover a 100 sq-km radius and will be mounted on a mini truck.
“The tropical storms like the kalbaisakhi are distinctly different from the thunder storms in European countries. But sadly, since most research done in India is based on the European thunderstorm, nor’westers cannot be predicted correctly. To predict the storms we will have to study its characteristics independently and that is what this mobile Doppler radar will help us to do,” said Sutapa Chaudhuri, head of atmospheric science and principal investigator of STORM.
“When you want to forecast nor’westers, you need to understand its dynamics otherwise, the forecast will not be accurate. And for the first time, we will come to know what is happening inside the cloud with the help of this radar. With the help of this information researchers would better understand when and where the nor’wester would strike,” said Chaudhuri.
The signals and images picked up by the mobile Doppler will be sent to the automatic mesonet network grid. These grids will further analyse the signal, which covers the most nor’wester-prone area between Kolkata and Asansol, and then will send it to the static Doppler radar over Secretariat Building in Kolkata.
“The nor’wester is a small-scale thunder storm which takes places within a small geographical area and for a very limited time period. If we do not have observatories in key areas, it becomes very difficult for metrologists to predict it. We will be studying the storm from this year. And if everything goes well, by 2009 the metrological department would be in a position to forecast the exact time, place and speed of the nor’westers,” said Chaudhuri.
To make students and researchers aware of how the nor’wester should be analysed, the atmospheric science department organised a 5-day basic training programme on thunderstorm research on March 12. “The objective was to create awareness among researchers about thunderstorms and analyse the physics, chemistry and numerical methods that goes behind it to make an accurate forecast,” said Chaudhuri.
mou.hindustantimes@gmail.com