Wayanad’s new X-band radar

Following severe floods and landslides in Kerala's Wayanad district, the Union Ministry of Earth Sciences has approved the installation of an X-band radar in the region. This advanced radar technology aims to enhance monitoring and forecasting capabilities, thereby improving disaster preparedness.

What is a Radar?

• Radar stands for "Radio Detection and Ranging." It is a technology that utilizes radio waves to detect the distance, speed, and physical characteristics of objects in its vicinity.
• How It Works:
  • A transmitter emits radio signals towards an object (e.g., clouds in meteorology).
  • The signal reflects off the object and returns to the radar device.
  • A receiver then analyzes the echoed signal to extract information about the object's properties.
• Applications: Weather radar, also known as a Doppler radar, is a common application of this device. The Doppler effect is the change in frequency of sound waves as their source moves towards and away from a listener. In meteorology, Doppler radars can reveal how fast a cloud is moving and in which direction based on how the cloud’s relative motion changes the frequency of the radiation striking it.
• Pulse-Doppler Radar A pulse-Doppler radar can measure the intensity of, say, rainfall by emitting radiation in pulses and tracking how often they’re reflected to the receiver.

What is an X-Band Radar?

• Doppler radar relies on Rayleigh scattering, when the scatterer is much smaller than the wavelength of the radiation.
• A radar trying to ‘see’ smaller particles like rain droplets or fog will need to use radiation of lower wavelengths, like in the X-band.
• An X-band radar is radar that emits radiation in the X-band of the electromagnetic spectrum: 8-12 GHz, corresponding to wavelengths of around 2-4 cm (this is in the microwave part of the spectrum.)
• The smaller wavelengths allow the radar to produce images of higher resolution. However, the greater the frequency of some radiation, the faster it will be attenuated. So X-band radars have a relatively shorter range.
• Functionality in Wayanad: In Wayanad, the X-band radar is expected to monitor particle movements, particularly soil, to provide early warnings for landslides. Its ability for high temporal sampling allows for rapid monitoring, crucial in detecting changes over short time frames.

Current Radar Infrastructure in India

• Historical Context: The India Meteorological Department (IMD) began utilizing radar technology in the 1950s, with the first indigenous X-band radar installed in 1970.
• Current Capabilities: India operates a network of X-band radars for storm detection and wind-finding, complemented by S-band radars for long-range observations.
• Future Expansion: As of September 2024, plans are in place to add 56 additional Doppler radars under the 'Mission Mausam' initiative, which aims to enhance meteorological infrastructure with an investment of ?2,000 crore.
• NISAR: NISAR (NASA-ISRO Synthetic Aperture Radar) is a joint project between NASA and ISRO, set to produce high-resolution Earth maps using radar imaging. The satellite is slated for launch in 2025, with total costs estimated at $1.5 billion, largely funded by NASA.
  • Technical Composition:
    • L-band Radar: Built by NASA (1.25 GHz, 24 cm).
    • S-band Radar: Developed by ISRO (3.2 GHz, 9.3 cm).