India Meteorological Department plans to upgrade ageing Chennai doppler weather radar

CHENNAI:India’s oldest Doppler Weather Radar (DWR), a critical piece of infrastructure located inside the Port Trust in Chennai, has reached its fag end and is showing signs of wear and tear. On World Meteorological Day, which was celebrated on Friday, city meteorologists felt it was time the ageing radar was replaced with more advanced DWR as Chennai was a strategically important location with major ports and naval base that need radar support for operations.  

Operational since 2002, Chennai S-Band Doppler Radar is the first to be procured by India Meteorological Department (IMD) from M/S Gematronik Gmbh, Germany. A year later, another one was installed in Kolkata. By 2006, two more such facilities were installed at Visakhapatnam and Machilipatnam.

Having served for nearly 16 years, Chennai radar has reportedly suffered some mechanical damages in the antenna unit of late, but it was promptly corrected. B Arul Malar Kannan, Regional Meteorological Centre’s IT cell head and incharge of Chennai DWR, told Express that the antenna itself weighed eight tonnes.”Imagine such a heavy machinery rotating on a gear wheel and motor for over 16 years. The mechanical damage is inevitable, he said.

Normally, the life of a radar in developed countries is a maximum 15 years, after which they go for major revamp. “However, our radar is doing just fine. Experts who have come and examined the mechanical damage in antenna unit said it was minor in nature. We did thorough maintenance this year in January and February. The radar will easily serve for another 3.4 years, by which time a new radar will be procured,” he said.

Kannan said there is a plan to put up a proposal for upgrading Chennai radar into a dual-polarimetric Doppler weather radar. There have been several advancements in signal processing and way of transmission. “All the recent radars for which tenders have been floated are for dual-polarimetric DWRs, which gives constituents of cloud. Currently, we imagine that the entire cloud is made of water droplets and derive some values, which is scientifically not correct, but by correlation we come up close to reality. But we will be having some variations. For instance, there might be cloud without rainfall, but the current system is estimating the value as if there is rain. So, when we go for upgrade of hardware, we will be looking at the systems also. When a system has outlived, a substitute has to be planned,” he said.

With Tamil Nadu being prone to adverse climatic condition like tropical cyclones during northeast monsoon, a hiccup-free DWR is a bare minimum.  For instance, during December 2016, when a very severe cyclonic storm ‘Vardah’ made its landfall near Chennai with the eye exactly passing over the city, it was this radar that tracked the entire system movement and gave timely updates that minimised the damage.   

The DWR provides advance information, enhancing the lead time so essential for saving lives and property in the event of natural disaster associated with severe weather. Though the conventional radars are able to track and predict cyclones, the DWR provides detailed information on storm’s internal wind flow and structure. The severity of the weather systems can thus be quantitatively estimated more accurately than ever before and more precise advance warnings can be generated for saving lives and property.

ISRO radar on standby

K J Ramesh, Director-General of Meteorology, IMD, said Indian Space Research Organisation (ISRO) has installed a new S-Band dual-polar radar, which can act as standby for Chennai. Indigenous efforts are being made to design and develop advanced radar technology for cost effectiveness and self-reliance. Under an MoU with ISRO, Department of Space, one S-Band DWR was designed, developed and installed at Sriharikota in 2004, but it encountered a lot of problems and now a new radar is installed in Sriharikota, which will be operational very shortly.


India’s radar network

In 2007, under modernisation of IMDs observational network, 13 old analogue radars were replaced with DWRs. These radars provide additional information of shape, size and classification of hydrometeors. Three M/s Metstar-make DWRs have been installed at Karaikal, Goa and Paradeep.

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