Home Radio waves Making waves: how a third radar can help the capital weather the storm better | Delhi News

Making waves: how a third radar can help the capital weather the storm better | Delhi News

New Delhi: In July last year, the INA settlement in South Delhi was flooded in a few areas after heavy rains. On the other hand, no rain was recorded at the meteorological observatories of Safdarjung, which is the city’s base station, and Lodhi Road, both nearby. To predict these localized flash floods and alert the public in real time, India’s Meteorological Department has now installed Doppler Weather Radar (DWR) in Ayanagar, making Delhi the first Indian city to have three such devices.
The radar antenna, which looks like a giant ball on a tower, detects weather systems like rain, thunderstorms, hail and cyclonic storms using radio waves, also known as radar beams. Radio waves travel at the speed of light and when the beam hits rain or hail, it bounces back to the radar. Meteorologists analyze the strength and time it took for the beam to return to predict the type of precipitation or other weather patterns and also measure their distance from the source radar.
In Delhi, IMD operates three DWRs using microwaves in the S, C and X bands. Met officials said the wavelength and frequency of the radar played an important role in determining the effective range of the radar to detect a meteorological phenomenon. The Delhi Airport S-band radar with a wavelength of 7.5-15cm has an effective radar range of 400 km. C-band DWR at the top of Mausam Bhawan on Lodhi Road with a wavelength of 3.8-7.5cm and can detect rain and thunderstorms over Delhi-NCR up to 250km away. “Polarimetric radar can tell if hail has formed in clouds,” said RK Jenamani, senior scientist at IMD. Delhi’s third DWR, Ayanagar’s X-band device, has a wavelength of 2.4 to 3.8 cm and can detect severe weather within a radius of 100 km around NCR.
According to Met officials, Delhi airport radar is used to detect severe weather and aerodrome warnings and forecast aviation weather hazards such as thunderstorms, dust storms, height and areas of cumulonimbus (associated with clouds that can produce thunder or lightning) and wind shear. . The Lodhi Road radar is used to detect thunderstorms and heavy rain over the Delhi-NCR region and to identify the type of precipitation – rain or hail – and to determine the intensity of the winds.
Met officials said the Ayanagar radar will help predict localized flash floods and identify flood areas and depths in real time at those locations. It will facilitate impact-based forecasting and warn markets, neighborhoods or streets of risks related to winds, thunderstorms and heavy rains. “The main difference between Lodhi Road and Ayanagar radars is the resolution. As the wavelength is shorter in Ayanagar, the resolution is high and will be useful in the three-hour weather warnings issued by IMD,” Jenamani said.
He said: ‘As this will help identify flood locations in real time, we can issue warnings of rain, dust storms or thunderstorms to the public. Say there is flooding in parts of Dhaula Kuan due to heavy rain, we can immediately issue a public advisory and the police can divert traffic to other roads.
TOI previously reported how IMD was developing an urban weather service for Delhi/NCR to forecast the impact of weather in specific locations, including flood hotspots in the city.