India Has 47 Doppler Weather Radars Covering 87% Area: Govt

Union Minister of State for Earth Sciences Jitendra Singh informed Parliament during the Winter Session that India currently has 47 Doppler Weather Radars (DWRs).

• These radars are used to survey weather patterns and improve forecasting.

Coverage Status

• According to the government, DWRs currently cover about 87% of India’s total geographical area.
• The government plans to install additional radars to cover the remaining uncovered regions.

How Doppler Weather Radars Work

• A DWR emits a beam of radio waves from an antenna.
• When the beam strikes atmospheric objects like raindrops or ice particles, the energy is scattered.
• Part of the energy reflects back to the radar:
  • Larger objects reflect more energy.
• By measuring the time taken for the signal to return, meteorologists can:
  • Detect raindrops in the atmosphere.
  • Measure their distance from the radar.

What Makes DWRs Special

• Unlike conventional radars, DWRs provide information on:
  • Position of weather targets
  • Movement and velocity of these targets
• This helps in accurately tracking storm intensity, direction and speed.

Types of DWRs Used in India

• The India Meteorological Department (IMD) uses:
  • S-band radars
  • C-band radars
  • X-band radars
• These radars can monitor weather systems within a coverage radius of about 500 km.

Specific Roles of Radar Bands

• X-band radar: Used for detecting thunderstorms and lightning.
• C-band radar: Useful for cyclone tracking and monitoring heavy rainfall.
• S-band radar: Suitable for long-range weather surveillance.

Role During Extreme Weather

• DWRs are crucial during extreme weather events such as:
  • Cyclones
  • Heavy rainfall
  • Severe storms
• They help meteorologists issue early warnings and improve disaster preparedness.

Doppler Effect Explained

• DWRs operate on the principle of the Doppler effect.
• Similar to sound waves:
  • An object moving towards the observer causes wave compression (higher frequency).
  • An object moving away causes wave stretching (lower frequency).
• This explains why a train whistle sounds louder while approaching and softer while moving away.

Scientific Origin

• The Doppler effect is named after Christian Doppler, a 19th-century Austrian physicist, who first explained the phenomenon.

Source: IE