What is in news : Recently, the India Meteorological Department (IMD) announced that it will install seven new doppler radars in Maharashtra, including Mumbai in 2021.

Doppler Radar:

• It is a specialized radar that uses the Doppler effect to produce velocity data about objects at a distance.
• Based on Doppler principle the radar is designed to improve precision in long-range weather forecasting and surveillance using a parabolic dish antenna and a foam sandwich spherical radome.
• DWR has the equipment to measure rainfall intensity, wind shear and velocity and locate a storm centre and the direction of a tornado or gust front.

What is doppler effect : When the source and the signal are in relative motion to each other there is a change in the frequency observed by the observer. If they are moving closer, frequency increases and vice versa.

Why the radar :

• They will guide meteorologists, particularly in times of extreme weather events like cyclones and associated heavy rainfall.
• As the radar observations will be updated every 10 minutes, forecasters will be able to follow the development of weather systems as well as their varying intensities, and accordingly predict weather events and their impact.

Existing radars

• East Coast: Kolkata, Paradip, Gopalpur, Visakhapatnam, Machilipatanam, Sriharikota, Karaikal and Chennai.
• West Coast: Thiruvananthapuram, Kochi, Goa and Mumbai.
• Other Radars: Srinagar, Patiala, Kufri, Delhi, Mukteshwar, Jaipur, Bhuj, Lucknow, Patna, Mohanbar, Agartala, Sohra, Bhopal, Hyderabad and Nagpur.