Context

• The India Meteorological Department (IMD) will install seven new doppler radars in Maharashtra, including Mumbai, this year.

Key Details about Doppler Radars

• Doppler radars of varying frequencies — S-band, C-band and X-band — are commonly used by the IMD to detect and track the movement of weather systems, 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.
• 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.

Back to Basics

About Doppler Radars

• 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.
• The electromagnetic pulse strikes an object such as a raindrop or a snowflake and the wave reflects back to the radar with data that can be analyzed by meteorologists.
• The meteorologists can use this information to determine specific areas where dangerous weather conditions exist.
• Weather radar utilizes either a solid-state or tube transmitter to send energy pulses (also known as radar beams) into the air to detect precipitation.

What is X-Band Radar?

• They have a smaller wavelength that makes them more sensitive to lighter particles.
• The X-band radar is used to detect thunderstorms and lightning.
• These radars are also more susceptible to attenuation as the smaller wavelength does not allow the radar beam to penetrate through heavy precipitation bands.
• The X-Band radar generally uses a smaller antenna dish and therefore is much less expensive than C- and S-Band radars.

What is C-Band Radar?

• The C-Band radars are often intended for short-range weather observation but can be used in medium- to long-range precipitation analysis.
• The C-band guides at the time of cyclone tracking.
• The beam does attenuate much more than the longer wavelength S-Band and therefore does not recognize precipitation rates as accurately as the S-Band.
• They are generally smaller and less expensive than S-Band weather radars, but more expensive than the smaller X-Band radar.

What is S-Band Radar?

• Its longer wavelength allows the beam to penetrate through several bands of precipitation, expanding the range for analysis further than the C-Band radar.

Source: IE

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