With Doppler radar, city may get more accurate forecasts

This monsoon, you will probably be able to plan your movements within the city better as you will get more precise forecasts and early warnings on heavy rainfall. Nikhil M Ghanekar reports.

This monsoon, you will probably be able to plan your movements within the city better as you will get more precise forecasts and early warnings on heavy rainfall.

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Mumbai’s first Doppler radar, which gives accurate, real-time monsoon forecast, is expected to become fully functional by the end of June, said officials with the India Meteorological Department (IMD).

The radar’s readings will help the city airport make more precise reschedules and plans and allow the Brihanmumbai Municipal Corporation (BMC) to sound out alerts and mitigate the impact of heavy rainfall.

The radar, which cost Rs10 crore, was installed in October 2010, but owing to technical glitches is not yet functional. “During the test run last November, the radar’s output had echoes and noises that showed inaccurate predictions,” said SG Kamble, director, Doppler Weather Radar, IMD, Mumbai.

Officials said the radar has been repaired by its Bangalore-based manufacturer, Bharat Electronics Limited (BEL), and will become operational after IMD conducts a 15-day endurance test. “We don’t want to risk giving out false warnings,” said Kamble.

“The radar is a value addition to our observatory, but not a magic wand that will solve all problems. It will measure the speed of approaching clouds, its height and in how much time the clouds will bring rainfall to the city,” said VK Rajeev, director, IMD, western region.

The idea to install a Doppler radar was mooted after the city received 994mm of rainfall on July 26, 2005, leading to large-scale death and devastation.

Surface rainfall intensity (SRI), a feature of the radar, will help measure the amount of rainfall the approaching clouds hold and predict the precipitation accumulation, which will help the BMC issue specific warnings about areas that may flood.

“A Doppler radar is efficient in tracking clouds that cause thunderstorms. The real-time forecasting helps give out accurate information on areas where it may rain heavily,” said Professor FN Karnekar, head, geography department, SP College, Pune.