On the 148th Foundation Day of the India Meteorological Department (IMD), the Ministry of Earth Science inaugurated the Doppler Weather Radar (DWR) Systems in Jammu & Kashmir, Uttarakhand, and Himachal Pradesh. This recent development has been a significant topic of discussion across India. The Ministry of Earth Science is also gearing up to establish an expansive Doppler weather radar network across the entire country by 2025. This nationwide setup aims to enhance the accuracy of forecasts related to extreme weather events.
Doppler Weather Radars: An Overview
The Doppler Weather Radars are designed based on the Doppler principle. The primary objective behind this radar system is to amplify the precision in long-range weather forecasting and surveillance. Each radar system is equipped with a parabolic dish antenna and a foam sandwich spherical radome. Among the pivotal roles of the DWR includes measuring rainfall intensity, wind shear and velocity, determining a storm centre, and tracking the direction of a tornado or gust front.
Simplifying Radar Concept
Radar, an acronym for Radio Detection and Ranging, is a device that harnesses electromagnetic waves in the microwaves region. It detects the location, altitude, intensity, and movement of moving and non-moving objects. More specifically, Doppler Radar is a sophisticated type of radar that uses the Doppler effect to gather velocity data about distant objects. The Doppler effect comes into play when the source and the signal relate to each other in motion, causing a change in the frequency observed by an observer. The device bounces a microwave signal off a designated target and analyses how the object’s motion has altered the frequency of the returned signal. This variation yields direct and highly accurate measurements of a target’s radial velocity relative to the radar.
Exploring Types of Doppler Radars
Doppler radars can be segmented into different categories based on the wavelength they operate at. These categories include L, S, C, X, K wavelengths. Among these, X band radars operate on a wavelength of 2.5-4 cm and a frequency of 8-12 GHz. They are more sensitive due to the smaller wavelength and hence can detect smaller particles.
Applications of X Band Radars
X band radars are widely used in studies related to cloud development. Their sensitivity towards tiny water particles makes them ideal for detecting light precipitation, such as snow. However, X-band radars attenuate easily, meaning their effectiveness reduces over long distances. Hence, they are primarily used for short-range weather observations. Their compact size allows for portability, as seen with the Doppler on Wheels (DOW). Major airplanes are often equipped with an X band radar to detect turbulence and other weather phenomena. This band is also shared by some police speed radars and some space radars.
