Doppler radar – UPSC Prelims

It is a device which uses electromagnetic waves in the microwaves region to detect location (range & direction), altitude, intensity and movement of moving and non-moving objects.

Doppler radar is an observational tool used for precisely monitoring and predicting severe weather events such as hailstorms, thunder storms, cyclones and tornados.

It uses Doppler effect by bouncing microwave signal off desired target to produce velocity data.

This data helps in analysing object’s motion by altered frequency of returned signal.

It mainly gives information about wind velocity and precipitation.

Doppler radar has radius of 250 km and helps in issuing forecasts two-three hours prior to severe weather conditions.

It can provide area specific rain and storm warnings which are beneficial for disaster management and emergency response, aviation and related services.

It can be used for wind speed measurements during cyclones and thunderstorms which is not possible in conventional weather radar.

When the source and the signal are in relative motion to each other there is a change in the frequency observed by the observer. If they are moving closer frequency increases and vice versa.

It does this by bouncing a microwave signal off a desired target and analysing how the object’s motion has altered the frequency of the returned signal.

This variation gives direct and highly accurate measurements of the radial component of a target’s velocity relative to the radar.