BENGALURU: The India Meteorological Department (IMD) is looking for space on the rooftop of the city’s tall skyscrapers to set up a Doppler Weather Radar (DWR) as it is unable to find an area without any structures in its 30-40 km radius. The presence of a structure interrupts accurate weather readings and forecasts that the radar puts out every three hours.
Given the varying weather conditions of Bengaluru, the city needs its own DWR for accurate and timely weather readings. Currently, IMD is using data available from the radars installed in Goa and Tamil Nadu, and via satellites. “Earlier, when space was available, the head office did not give permission. Now when we have permission, location is a problem. Since there are no large vacant spaces in Bengaluru, we have suggested using the rooftop of a tall building. We are requesting private companies and the government for space,” said an IMD official.
For DWR, 10x10 metres of space is needed. However, the dome of the radar has to be at the lowest elevation angle of 0.2 degrees. This angle is ideal for long-distance weather evaluations, to read clouds at low levels and other conditions, and to give accurate weather readings. But for installation at this angle, there should not be any high-rise structures within a radius of 30-40 km as the DWR’s coverage range would then get obstructed.
“As it is not possible in the city, we are looking for space atop a building that is 25 storeys and above. Once allotted, the government will have to ensure that no other building higher than that comes up within its range, as readings will be affected. A Large, clear area is needed to see the long echo (the electronic signals that reflect back to the radar’s antenna),” the official said.
“A DWR is needed to study thunderstorms, cloud locations, their depth, direction and wind pattern. Once installed, accurate location-wise nowcasts (very short-term forecasts) can be obtained every three hours. We had earlier thought of GKVK, but that did not fit our requirements. We then zeroed in on Hessarghatta, but there is no guarantee from the government on prohibiting further development around the site in the future.” IMD is facing a similar space problem in Chennai. Although a DWR is installed near the coast, its 360-degree coverage is affected on one side because of tall buildings in the vicinity.