‘Doppler locates clouds 250km away’

After a year of struggling with water cuts and food inflation, thanks to last year’s inadequate rainfall, the city is now hoping for a monsoon that will fill up its lakes and help the country’s food production. With the city receiving over 2,000mm rainfall since June 11, the official onset of the monsoon, Sathi Devi, director of Mumbai Met Department, spoke to DNA about favourable conditions of the south west monsoon and its progress in the state.

Last year’s erratic and weak monsoon left citizens worried about a repeat this year. In your estimation, what are the chances of a normal monsoon over the next three months?
In 2009, just before the onset of the monsoon, a cyclone formation over the Arabian Sea considerably weakened it. But, this year, there were no fears as the rains hit Kerala on May 31, and reached the city by June 11. Its progress was briefly halted by June 17 around Mumbai and Pune, but now it is well on its way to covering the entire country before July 15. The low pressure system formed over the country will bring in plenty of rains this year. However, the city will experience a few dry spells in between heavy showers over the next three months. Citizens should not panic thinking the monsoon has weakened due to this.

Has there been any change in the pattern of rainfall since the last few monsoons? How will the high summer temperature help this monsoon?
During the summer, the land gets warmer than water, creating a low pressure system. The more heat on land, the warmer the temperature. This enables a strong pull from the low pressure system over land. High summer temperatures always help the progress of the monsoon. There were brief concerns over the sudden halting of monsoon on June 17. However, it has since moved and is progressing on its set course. The whole of Maharashtra, including Konkan, Marathwada and Vidharbh regions are fully covered by rain clouds.

The Doppler Radar currently being installed is said to bring better forecast ability. When can we expect it to be operational and what benefits will be seen in forecast?
We are expecting that the radar will be fully operational by mid-July. Currently, we are using satellite pictures and numerical weather prediction models to forecast the rains. Once the radar is installed, we will be able to understand the height of the clouds, direction, speed, wind activity inside the cloud, etc. The radar will be able to locate cloud activity around 250km from the area. We will also be able to accurately predict the intensity of the rainfall. The regional centres located in the eastern coast of the country such as Kolkata, Chennai, Vishakapatnam are predicting weather using the doppler radar. It is immensely helpful and will bring more information to us enabling better forecast.

Will there be more additions in the form of sophisticated devices to enable better weather forecasting?
Recently, our request for a Public Weather System (PWS) has been approved by the Delhi headquarters. We will soon be getting it at the Mumbai centre. The PWS is a system which enables timely and easy dissemination of information, weather alerts, coastal warnings, etc, to the public. Currently, we coordinate with the BMC’s disaster management, traffic control, ports, fishermen, news channels and other government bodies through fax, email, website, etc. With PWS, there will be minimal manual labour. Once scheduled, the system will send the information to all offices on its own every few hours.