Doppler Weather Radar Network

Union Minister of State for Earth Sciences has said that the entire country will be covered by Doppler Weather Radar Network by 2025 to predict extreme weather events more accurately.

Details –

• IMD has announced to cover the entire country under sophisticated radar network by deploying 25 additional Doppler Weather Radars (DWRs).
• To establish 720 District Agro Meteorological Units (DAMUs) to provide more precise farm-related advisories and forecasts to farmers by 2025.
  • The IMD also decided to increase its agro-meteorological service facilities from 3,100 blocks in 2023 to 7,000 blocks in 2025.
• It also announced to bring Delhi, Kolkata and Guwahati under its urban flood warning system in coming years.
  • The urban flood warning system, introduced in Mumbai in July 2020, is currently operational in two cities including Chennai.

Significance of this move –

• It can prove to be an important tool to avert disasters in many states, specifically the ones struck by thunderstorms lightning, floods and heavy rains. In 2022, thunderstorms and lightning claimed the highest 1,285 lives (58% of total casualties of 2,227) followed by floods and heavy rains (835) in India.
• Besides protecting lives, warning and advisory services will help farmers and fishermen to improve their income.

What is a ‘weather radar’?

• Weather radar is also known as Doppler weather radar.
  • It is different from normal radar as it uses the Doppler Effect principle to provide information about weather forecast.
    • Doppler Effect refers to the change in wave frequency during the relative motion between a wave source and its observer.
  • Doppler radar systems provide accurate information regarding the movement of targets as well as their position.
• It is an instrument that sends pulses of electromagnetic energy into the atmosphere to find precipitation, determine its motion and intensity, and identify the precipitation type such as rain, snow or hail.
• When the electromagnetic pulse strikes an object such as a raindrop or a snowflake, the wave reflects back to the radar with data that can be analysed by meteorologists.

How does it work?

• Weather radar utilises either a solid-state or tube transmitter to send energy pulses (also known as radar beams) into the air to detect precipitation.
• This focused beam radiates outward from an antenna (also known as a radar dish).
• If the radar beam bounces off precipitation such as rain or hail, the beam will return to the weather disk, where the data is processed into various parameters.
• This enables a meteorologist to analyse and interpret the type of weather occurring dozens of miles away from the radar.

Doppler radars in India –

• In India, Doppler radars of varying frequencies — S-band, C-band and X-band — are commonly used by the IMD to track the movement of weather systems and cloud bands, and gauge rainfall over its coverage area of about 500 km.
• The radars guide meteorologists, particularly in times of extreme weather events like cyclones and associated heavy rainfall. An X-band radar is used to detect thunderstorms and lightning whereas C-band guides in cyclone tracking.
• With the radar observations, updated every 10 minutes, forecasters can follow the development of weather systems as well as their varying intensities, and accordingly predict weather events and their impact.