X-band Radar 

Syllabus: GS1/Climatology/GS3/Science and Technology

Context

• After devastating floods and landslides in Kerala’s Wayanad district in July 2024, the Union Ministry of Earth Sciences approved an X-band radar to be installed in the district.

What is Radar?

• Radar is short for ‘radio detection and ranging’. The device uses radio waves to determine the distance, velocity, and physical characteristics of objects around the device. 
• Working: A transmitter emits a signal aimed at an object whose characteristics are to be ascertained (in meteorology, this could be a cloud).
  • A part of the emitted signal is echoed by the object back to the device, where a receiver tracks and analyses it.
• 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. 
• Application: 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.
  • This way, modern Doppler radars can monitor weather conditions and anticipate new wind patterns, the formation of storms, etc.

X-band Radar

• 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.
• Significance: The smaller wavelengths allow the radar to produce images of higher resolution. 

Use of Radars in India 

• The India Meteorological Department (IMD) started using radar for weather applications in the early 1950s. 
• The first indigenously designed and manufactured X-band storm detection radar was installed in 1970 in New Delhi.
  • In 1996, IMD replaced 10 outdated X-band radars with digital X-band radars.
• India also uses S-band radars (2-4 GHz) for long-range detection.
  • The first S-band cyclone detection radar was installed in Visakhapatnam in 1970 and the first locally made variant was commissioned in Mumbai in 1980.
• Mission Mausam: The Union Cabinet cleared ‘Mission Mausam’ to upgrade meteorological infrastructure in the country.
  • This includes installing up to 60 meteorological radars until 2026 under the first phase.

NISAR

• It is jointly developed by NASA and ISRO named as‘NASA-ISRO Synthetic Aperture Radar’ (NISAR).
• It will use radar imaging to produce a high-resolution map of the earth’s landmasses.
  • Its payload consists of an L-band an S-band radar, together they will track and record changes in the earth’s various natural processes.
• It is currently expected to be launched onboard an ISRO GSLV Mk II rocket in 2025.

Source: TH