Doppler Weather Radar (DWR)

In News 

• Recently, the Union Minister of State (Independent Charge) Science & Technology inaugurated the latest upgraded state-of-the-art Doppler Weather Radar (DWR) & Indigenous GPS based Pilot Sonde at Indian Meteorological Office in Jammu.

Significance of the move

• The  X-Band Doppler Weather Radar will help in providing real-time monitoring and reporting of weather events affecting the Jammu region.
• It will be helpful in providing weather forecasts in different sectors including agriculture and tourism forecasts especially for the pilgrims of Mata Vaishno Devi.

What is Doppler Weather Radar (DWR)?

• It is a specialized radar that uses the Doppler effect to produce velocity data about objects at a distance.
• It is designed to improve precision in long-range weather forecasting and surveillance using a parabolic dish antenna and a foam sandwich spherical radome.
• It has the equipment to measure rainfall intensity, wind shear and velocity and locate a storm centre and the direction of a tornado or gust front.
• It provides advanced information, enhancing the lead-time so essential for saving lives and property, in the event of natural disaster associated with severe weather. 
• Division of  Doppler Radars and their applications: Doppler radar can be divided into several different categories according to the wavelength which are L, S, C, X, K.

                                           Image Courtesy:engineeringsadvice.com

• L Band Radars: Operate on a wavelength of 15-30 cm and a frequency of 1-2 GHz.
  • Mostly used for clear air turbulence studies.
• S-band radars: They operate on a wavelength of 8-15 cm and a frequency of 2-4 GHz. Because of the wavelength and frequency, S-band radars are not easily attenuated. This makes them useful for near and far range weather observation. 
  • The drawback to this band of radar is that it requires a large antenna dish and a large motor to power it.

• C band radars: They operate on a wavelength of 4-8 cm and a frequency of 4-8 GHz. Because of the wavelength and frequency, the dish size does not need to be very large. 
  • This makes C band radars affordable for TV stations. The signal is more easily attenuated, so this type of radar is best used for short-range weather observation.
• X-band radars: They operate on a wavelength of 2.5-4 cm and a frequency of 8-12 GHz. Because of the smaller wavelength, the X band radar is more sensitive and can detect smaller particles.
  • It is used to detect thunderstorms and lightning.

• K band radars: They operate on a wavelength of .75-1.2 cm or 1.7-2.5 cm and a corresponding frequency of 27-40 GHz and 12-18 GHz. This band is split down the middle due to a strong absorption line in water vapour. This band is similar to the X band but is just more sensitive.

Source: PIB