DLOC Principles of Meteorological Doppler Radar:
WSR-88D Fundamentals

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Radar Sensitivity

The minimum detectable signal by a radar is related to its sensitivity. Radar sensitivity depends on several factors, including transmitted power, received power, antenna size, and signal-to-noise ratio. For instance, if two radars transmitted the same amount of power but had different beamwidths, then the one with the narrower beam would have greater sensitivity due to its greater power density. This would result in the detection of smaller targets at greater ranges.

Reflectivity products can report a minimum value as low as -32 dBZ. However, it's very rare (even in long pulse mode) that the radar will be sensitive enough to detect targets with such weak power returns. For instance, the dual-polarization upgrade to the WSR-88D resulted in a loss of sensitivity of approximately 3 dB. However, comparisons of Reflectivity products with and without this sensitivity loss resulted in no operational impacts based on forecaster assessment.

Next Page: Practice Exercise #1
or proceed on to: Section 2: Radar Equation and Reflectivity